ML18348B117
| ML18348B117 | |
| Person / Time | |
|---|---|
| Issue date: | 10/31/2018 |
| From: | Kent Howard Advisory Committee on Reactor Safeguards |
| To: | |
| Howard K | |
| References | |
| NRC-3949 | |
| Download: ML18348B117 (395) | |
Text
Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION Title: Advisory Committee on Reactor Safeguards License Renewal Subcommittee Open Session Docket Number: (n/a)
Location: Rockville, Maryland Date: Wednesday, October 31, 2018 Work Order No.: NRC-3949 Pages 1-395 NEAL R. GROSS AND CO., INC.
Court Reporters and Transcribers 1323 Rhode Island Avenue, N.W.
Washington, D.C. 20005 (202) 234-4433
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2 3
4 DISCLAIMER 5
6 7 UNITED STATES NUCLEAR REGULATORY COMMISSIONS 8 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 9
10 11 The contents of this transcript of the 12 proceeding of the United States Nuclear Regulatory 13 Commission Advisory Committee on Reactor Safeguards, 14 as reported herein, is a record of the discussions 15 recorded at the meeting.
16 17 This transcript has not been reviewed, 18 corrected, and edited, and it may contain 19 inaccuracies.
20 21 22 23 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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1 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION
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ADVISORY COMMITTEE ON REACTOR SAFEGUARDS (ACRS)
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LICENSE RENEWAL SUBCOMMITTEE
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OPEN SESSION
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WEDNESDAY OCTOBER 31, 2018
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ROCKVILLE, MARYLAND
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The Subcommittee met at the Nuclear Regulatory Commission, Three White Flint North, Room 1C3 & 1C5, 11601 Landsdown Street, at 8:30 a.m., Gordon R. Skillman, Chairman, presiding.
COMMITTEE MEMBERS:
GORDON R. SKILLMAN, Chairman MICHAEL L. CORRADINI, Member RONALD G. BALLINGER, Member DENNIS C. BLEY, Member*
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2 CHARLES H. BROWN, JR., Member VESNA B. DIMITRIJEVIC, Member WALTER KIRCHNER, Member JOSE MARCH-LEUBA, Member JOY L. REMPE, Member PETER RICCARDELLA, Member ACRS CONSULTANT:
STEPHEN SCHULTZ DESIGNATED FEDERAL OFFICIAL:
- Present via telephone NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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3 AGENDA Opening Remarks ...................................4 Member Comments ..................................10 Statement from the Deputy Director of the Division of Material and License Renewal .........14 Applicant Remarks ................................17 Overview and Timeline for ASR Issue at Seabrook.................................19 ASR Presentation, Load Factors, Methodology, Field Data, Structural Evaluation...........65 NRC Review of ASR................................ 198 Public Comments.................................. 289 Adjournment...................................... 296 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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4 1 P R O C E E D I N G S 2 8:30 a.m.
3 CHAIRMAN SKILLMAN: Ladies and gentlemen, 4 good morning. This meeting will now come to order.
5 This is a meeting of the ACRS's Plant License Renewal 6 Subcommittee. I am Gordon Skillman. I'm Chairman of 7 the ACRS License Renewal Subcommittee.
8 ACRS members in attendance are Dr. Ronald 9 Ballinger, Dr. Peter Riccardella, Dr. Walter Kirchner, 10 Dr. Joy Rempe, Dr. Michael Corradini, Dr. Jose 11 March-Leuba, Dr. Vesna Dimitrijevic, and Dr. Dennis 12 Bley by phone.
13 Our colleague, Mr. Charlie Brown, will 14 attend later. We welcome Dr. Stephen Schultz as our 15 consultant on this topic, and Mr. Kent Howard of the 16 ACRS staff is the designated federal official for this 17 meeting.
18 NextEra, the licensee for Seabrook 19 station, is following the required protocol for 20 requesting a license renewal for 20 years for the 21 Seabrook Station.
22 This special meeting is convened to provide 23 focus on one unique topic effecting license renewal 24 of this nuclear power plant, and that topic is 25 alkali-silica reaction on structures, systems, and NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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5 1 components within the scope of the license renewal at 2 the Seabrook Station.
3 Because of the critical nature of this 4 topic, the ACRS considered this independent meeting 5 appropriate and important to enable stakeholder, 6 licensee, and staff participation.
7 In this Subcommittee meeting, we expect 8 the staff and NextEra to brief the Subcommittee on the 9 status of the alkali-silica reaction issue at Seabrook.
10 The Subcommittee will gather information, analyze 11 relevant issues, formulate a proposed position for 12 deliberation for deliberation for the full committee 13 if needed.
14 As we begin, I would like to emphasize 15 several points relating to this specific meeting. One 16 of Seabrook Station's required aging management 17 programs addresses structures, systems, and 18 components.
19 The AMP, Aging Management Program, that 20 addresses SSCs, structures, systems, and components, 21 must address the suitability of the SSC for the 22 mechanical loading for the period of extended 23 operation.
24 The alkali-silica reaction discovered at 25 Seabrook obligates determining its impact on those SSCs NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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6 1 within the scope of license renewal Seabrook.
2 The ASR imposes structural loadings that 3 are different than those originally addressed in 4 Seabrook's operating license. NextEra is required to 5 formally address those different structural loadings 6 through a license amendment request.
7 NextEra has submitted a license amendment 8 request to address the different loadings. The license 9 amendment request is based on research and analysis 10 and data intended to demonstrate the acceptability of 11 ASR in those SSCs that are required both for present 12 and for future plant operation.
13 This meeting is focused on determining 14 whether the SSCs affected by ASR and addressed by the 15 AMP and the license amendment request are acceptable 16 for the requested period of extended operation that 17 NextEra has requested in their license renewal 18 application for Seabrook.
19 The ACRS was established by statute and 20 is governed by the Federal Advisory Committee Act, FACA.
21 That means that the committee can only speak through 22 its published letter reports. Let me say that again 23 so that it's clear in everyone's mind. That means that 24 the committee can only speak through its published 25 letter reports.
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7 1 This meeting, a Subcommittee meeting, 2 enables the members to express their comments and 3 concerns, and those comments may or may not find their 4 way into the final letter of report. That means we 5 speak as individuals.
6 The ACRS reviews and advises the Commission 7 with regard to licensing and operation of production 8 and utilization facilities and related safety issues, 9 the adequacy of proposed reactor safety standards, 10 technical and policy issues related to the licensing 11 of evolutionary and passive plant designs, and other 12 matters referred to it by the Commission.
13 The ACRS section of the U.S. NRC public 14 website provides our charter, bylaws, letter reports, 15 and full transcripts of all Subcommittee meetings, 16 including slides presented at the meetings.
17 The rules for participation in today's 18 meeting were announced in the Federal Register. The 19 meeting was announced as open, but here it is. Portions 20 may be closed as needed to protect information 21 proprietary to NextEra or its vendors pursuant to 5 22 USC 552BC4.
23 We have, I repeat, we have received written 24 comments and requests for time to make oral statements 25 from members of the public during today's meeting.
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8 1 A transcript of the meeting is being kept 2 and will be made available as stated in the Federal 3 Register notice. Therefore, we request that 4 participants in this meeting please use the microphones 5 located throughout the meeting room when addressing 6 the Subcommittee.
7 Participants are requested for first 8 identify themselves and speak with clarity and volume 9 so that they can be readily heard.
10 A telephone bridge line has been 11 established for this meeting. We have several members 12 of the public, one ACRS member, and perhaps others from 13 the public listening in on the public bridge line.
14 This public line will be closed during the 15 closed section of the meeting and will be reopened 16 during the open session. We will close the public line 17 as necessary if that is required.
18 To preclude interruption of the meeting, 19 we ask that you please mute your individual lines during 20 the presentations, and for those in the room, we request 21 that you please silence all your phones and electronic 22 devices.
23 Before turning the meeting over to Joe 24 Donoghue of DMLR, and this is different for ACRS, I 25 want to provide opportunity for ACRS members to express NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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9 1 their expectations for this meeting. We don't normally 2 do this.
3 My concern is very often the ACRS is seen 4 as a group of individuals who are perhaps not too willing 5 to engage or perhaps not express their thoughts. Since 6 this meeting is different, I want to give the members 7 an opportunity to provide comment before we begin so 8 that NextEra and the staff can hear, if you will, how 9 the ACRS thinks.
10 I will begin by stating that I am interested 11 in both the staff's and licensee's clear statements 12 that communicates their understanding of the 13 seriousness of the ASR issue at Seabrook, clarity 14 regarding the scope of the structures, systems, and 15 components affected by ASR, clarity regarding the 16 extent of condition resolution and research of this 17 phenomenon, demonstration of the discipline related 18 to understanding the as-found state and of the 19 progression of the ASR phenomenon, and the thoroughness 20 of the licensee's plans, actions, commitments, and 21 programs to fully and comprehensively address ASR.
22 I invite my colleagues to offer their 23 opening comments. I will begin by asking Dr.
24 Dimitrijevic.
25 MEMBER DIMITRIJEVIC: So this is my first NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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10 1 meeting on this issue, so my goal of this thing is to 2 see that we have a full understanding of the issue and 3 status. So I have a very small expectation just to 4 get completely familiar and understanding of the issue, 5 okay.
6 CHAIRMAN SKILLMAN: Thank you, Vesna.
7 Dr. Corradini?
8 MEMBER CORRADINI: I also am trying to 9 learn about the issue, so my only comment is I think 10 the background information we've gotten is quite 11 comprehensive, so I think that will help.
12 CHAIRMAN SKILLMAN: Thank you, Mike. Dr.
13 Rempe?
14 MEMBER REMPE: Thank you, Dick. I, in 15 reading through the material, was very interested in 16 why there was such a long time between the 2010, 2009 17 initial observation of ASR and then the time frame 18 before another indication of it was identified in 2014.
19 20 ASR is a known phenomena in other 21 industries and applications, and I am interested in 22 that lag because I want to understand that you're not 23 only monitoring the ASR identified structures, but 24 other structures that might be susceptible, okay?
25 Thanks.
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11 1 CHAIRMAN SKILLMAN: Thank you, Joy. Dr.
2 Riccardella?
3 MEMBER RICCARDELLA: Yes, thank you, Dick.
4 I'm a mechanical engineer with a background in 5 structure strength and materials, structural analysis, 6 and probably the closest thing we have on this committee 7 to a structural engineer. I've spent a lot of times 8 in the last couple of weeks reviewing the background 9 information, which I found to be a very, very impressive 10 program and comprehensive.
11 I have some questions, and I guess my goal 12 for this meeting is to get those questions answered 13 and get all of the information we need for our full 14 committee deliberations.
15 CHAIRMAN SKILLMAN: Thank you, Pete. Dr.
16 Kirchner?
17 MEMBER KIRCHNER: Thank you, Dick. My 18 particular interest in this meeting is to see how the 19 test program that was conducted bounds the problem based 20 on the condition assessment and project impact of this 21 ASR over the applicant's, you know, the extended license 22 period. Thank you.
23 CHAIRMAN SKILLMAN: Thank you, Walt. Dr.
24 March-Leuba?
25 MEMBER MARCH-LEUBA: As opposed to my NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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12 1 members, I want to start by apologizing for two things.
2 First, it will take a little while to understand my 3 accent, so I will try to speak slowly into the 4 microphone, and second, I am not an expert on this 5 whatsoever.
6 I mean, ASR, my extent of ASR knowledge 7 is wherever there's a snow forecast, I put the snow 8 on my driveway, and when the snow is away, the driveway's 9 kind of chipped, so that's what I know.
10 So considering the questions, I wanted to 11 apologize, but the questions I will ask you during the 12 presentation, consider me an uninformed member of the 13 public and I will try to kind of inform the public 14 through my questions.
15 CHAIRMAN SKILLMAN: Thank you, Jose. Dr.
16 Ballinger?
17 MEMBER BALLINGER: Thank you, Dick. I 18 really can't add anything to what everybody else has 19 said except for the fact that I live in the EPZ for 20 Seabrook. More importantly, the Airfield Café and the 21 Max BMW motorcycle place is in the EPZ, so I have a 22 very keen interest in what's going on.
23 My area is corrosion and materials, and 24 I've actually done work related to ASR, so my 25 expectation is to understand that you folks understand NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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13 1 the process and what's going on, and in particular, 2 what Walt has to say, how the testing has bounded the 3 conditions at Seabrook.
4 CHAIRMAN SKILLMAN: Thank you, Ron. Dr.
5 Schultz?
6 MR. SCHULTZ: My experience is in 7 technical support for supporting operating reactors 8 as a licensee, and I'm sure the Committee wants to 9 develop today a full understanding of the requirements 10 of the ongoing and forward-looking plan and program 11 for addressing ASR.
12 How has it been implemented for the current 13 operation of the plant? What modifications are 14 required in the near term as a result of the license 15 amendment commitments by the licensee? What if 16 anything in the current program is still in flux?
17 And I want to, we want to assure that the 18 applicant, the Committee, and the staff will be certain 19 that the program for addressing ASR is fully in place 20 to support the application for license renewal.
21 CHAIRMAN SKILLMAN: Thank you, Steve.
22 Dr. Bley, may I ask you, please, to offer any comment 23 or expectation you might have, sir?
24 MEMBER BLEY: No, thank you, Dick. I have 25 nothing additional to add, but I am interested in how NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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14 1 the test results have proceeded. Thanks.
2 CHAIRMAN SKILLMAN: Thank you, Dennis.
3 With that, I'm going to turn the meeting over to Joe 4 Donoghue, the Deputy Director of the Division of 5 Material and License Renewal. Joe, welcome, and thank 6 you. Please proceed.
7 MR. DONOGHUE: Good morning. Thank you, 8 Chairman Skillman, members of the ACRS License Renewal 9 Subcommittee, and other ACRS members in attendance.
10 Yes, I'm Joe Donoghue. I'm the Deputy Director of the 11 Division of Materials and License Renewal.
12 We thank the Subcommittee for the 13 opportunity to present an overview of the NRC's 14 activities associated with the review of the 15 alkali-silica reaction or ASR effecting concrete 16 structures at Seabrook Station Unit 1, as well as the 17 results of the staff's review of the applicant's 18 methodology for assessing structures impacted by ASR 19 that was submitted in a license amendment request, and 20 the staff's review of the aging management programs 21 that are credited for addressing ASR in their license 22 renewal application.
23 I'll just add that there's two separate 24 actions that are affected by this, the license amendment 25 request as well as the license renewal. They depend NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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15 1 on the same methodology and the license renewal depends 2 on, it involves a program that's going to, the aging 3 management program that's going to address it.
4 The NRC has spent considerable time and 5 effort on the ASR issue to ensure that it was 6 appropriately addressed for operability as part of the 7 current licensing basis and in the aging management 8 program's credit for the license renewal.
9 Just to highlight the extent of the effort, 10 we had site resident inspectors performing regular 11 inspections to assess operability. We had Region I 12 inspection staff who were supported by headquarters' 13 technical staff conducting problem identification and 14 resolution inspections onsite, and we did inspections 15 at the testing site.
16 We had senior structural engineers from 17 the Division of Engineering assessing the aging 18 management programs for ASR, the structural assessment 19 methodology, and the large-scale testing that was 20 conducted at Ferguson Structural Engineering Lab at 21 the University of Texas. They were also supported by 22 structural engineers from Brookhaven National Lab.
23 The staff also had a team of reviewers and 24 experts that we established back in 2012 to coordinate 25 all of our activities.
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16 1 In July 2012, the staff presented the 2 safety evaluation report with open items to the ACRS 3 License Renewal Subcommittee, and of those open items 4 that existed at the time, the one associated with aging 5 management for ASR dominated the discussion.
6 Today, the staff will present its review 7 of the enhanced and newly developed aging management 8 programs that address ASR that are the basis for the 9 SAR, and that we think resolve this open item. We will 10 present the complete SER and address the remaining open 11 items in a meeting in a couple of weeks to the 12 Subcommittee.
13 The project manager for the Seabrook 14 license renewal safety review and who will lead us 15 through the presentation is Butch Burton seated 16 opposite me in the room.
17 Part of the management team that are here 18 with me today are Eric Oesterle next to me, Chief of 19 the Projects Branch in our division, Kamal Manoly who 20 is Senior Level Advisor for Structural Mechanics from 21 the Division of Engineering, and other division and 22 NRR office technical experts and managers.
23 We also have in the audience and on the 24 phone other staff who supported the review, as well 25 as Region I staff who performed the facility inspections NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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17 1 and supported the license renewal reviews, and you'll 2 be hearing from one of them in the presentations later 3 today.
4 We look forward to a productive discussion 5 with the ACRS Subcommittee, and as always, we will 6 address any questions on this review that you may have.
7 And at this time, I'd like to turn the presentation 8 to NextEra and their Regional Vice President for the 9 Northern Region, Mr. Eric McCartney, to introduce his 10 team.
11 MR. McCARTNEY: Thank you, Mr. Donoghue.
12 As he said, my name is Eric McCartney and I've been 13 the Regional Vice President for NextEra Energy 14 responsible for the Seabrook Station, Point B Station, 15 and Duane Arnold Station for the past year.
16 I've been in the commercial industry for 17 33 years now. I started my career as an unlicensed 18 operator and I have served as the plant manager or site 19 vice president at five different stations in the course 20 of that career. I was a senior reactor operator, 21 licensed operator at the Harris Nuclear Plant outside 22 of Raleigh, North Carolina.
23 We're pleased to have the opportunity to 24 discuss our structures monitoring program specifically 25 as it relates to alkali-silica reaction with the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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18 1 Committee today.
2 NextEra has expended a tremendous amount 3 of time and resources to develop a clear understanding 4 of this issue and develop a comprehensive structures 5 monitoring program that provides us assurance that we 6 can operate the plant safely and reliably not only for 7 the current license, but for the extended license that 8 we are requesting.
9 We recognize that this condition is a life 10 of the plant condition, and as a corporation, we remain 11 committed to engage in anything and all activities we 12 need to do to ensure that we operate this plant with 13 the safety margins that it's designed to operate with.
14 We have worked diligently with industry 15 leaders to ensure that we gain any expertise that we 16 may lack at our facility. We have engaged with the 17 folks that we need to, to make sure that we clearly 18 understanding this. Many of them are here today that 19 will help in the discussion.
20 We also recognize the obligation that we 21 have to the industry to share what we've learned as 22 we go forward with this process. We remain engaged 23 with INPO through our membership.
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19 1 learned to ensure that the industry and other facilities 2 in other industries can gain the knowledge that we've 3 gained as we've worked through this process.
4 Today, we'll talk about our large-scale 5 testing program. We'll talk about the development of 6 the methodologies to monitor the loads, and we'll talk 7 about our structures monitoring program, and provide 8 a comprehensive discussion of both of those, and I 9 believe we'll answer all of the questions and concerns 10 that you articulated as you went through your questions.
11 If we could go to our slide?
12 MR. BURTON: Good morning. As Joe said, 13 my name is Butch Burton. I'm the project manager for 14 the NRC staff safety review of the license renewal 15 application for Seabrook station Unit 1.
16 As was already mentioned, we're here today 17 to discuss the staff's closure of the open item related 18 to the alkali-silica reaction known as ASR related to 19 the Seabrook license renewal application.
20 The closure of this open item is documented 21 in the staff's safety evaluation report for the license 22 renewal application and is supported by the staff's 23 safety evaluation on a related license amendment 24 request. Both of these documents were issued on 25 September 18, 2018, and provided to the Subcommittee.
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20 1 We'd like to begin this meeting by 2 providing you with an overview and timeline of the NRC's 3 activities related to ASR at Seabrook. We'll then turn 4 the meeting over to representatives from NextEra Energy 5 Seabrook, which is the licensee for Seabrook, who will 6 discuss their activities on this project.
7 Following the NextEra presentation, the 8 staff will discuss its review, audit, and inspection 9 activities associated with ASR at Seabrook, and we'll 10 discuss the basis for its closure of the ASR open item 11 in the SER.
12 As we stated, portions of this meeting will 13 be closed to the public. The staff has not prepared 14 presentations for the closed portion of the meeting, 15 but will be available to answer any questions from the 16 Subcommittee during the closed portion of the meeting.
17 Seabrook is a single-unit Westinghouse 18 four-loop pressurized water reactor located just south 19 of Portsmouth, New Hampshire. Its 40-year operating 20 licensed was issued on March 15, 1990, and the unit 21 began commercial operation on August 19, 1990. NextEra 22 is the principal owner and operator of the unit.
23 On May 25, 2010, NextEra submitted a 24 license renewal application requesting renewal of its 25 operating license to allow operation for 20 years beyond NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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21 1 the expiration date of its current license. Issuing 2 a renewed license would allow the plant to operate 3 through March 15, 2050.
4 In 2009, NextEra identified pattern 5 cracking in sections of walls and certain below grade 6 structures at Seabrook. In 2010, NextEra confirmed 7 that this cracking was due to ASR. In order to address 8 this ASR issue, NextEra pursued two licensing actions.
9 10 It amended its existing license renewal 11 application to include activities to manage aging 12 resulting from ASR and it submitted a license amendment 13 request to address the nonconforming condition with 14 its current license resulting from the effects of ASR.
15 As you can see, these actions were 16 addressed along two parallel tracks. The upper track 17 shows that NextEra submitted an amendment to its license 18 renewal application and shows the staff's review and 19 the issuance of its review findings in the safety 20 evaluation report.
21 The lower track shows that NextEra 22 submitted a license amendment request to address ASR 23 in current licensing space, and shows the staff's review 24 and the issuance of its review findings as the final 25 safety evaluation.
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22 1 As shown, the identification of ASR at 2 Seabrook led to an immediate impact on the license 3 renewal application review schedule and a prolonged 4 time period of NRC oversight activities to fully 5 understand the issue. The NRC's activities will be 6 discussed in more detail during our presentation this 7 afternoon.
8 Before I turn it over to NextEra, I did 9 want to reemphasize what Chairman Skillman mentioned 10 before, that portion of NextEra's presentation will 11 be closed. During that time, we will ask members of 12 the public to leave the room and we will also close 13 the public bridge line. After the closed portion of 14 the meeting is completed, we'll bring members of the 15 public back in and reopen the public bridge line, and 16 they'll let us know when it's appropriate to do that.
17 Now I'll ask representatives from NextEra 18 to discuss their activities to address ASR at Seabrook.
19 MEMBER MARCH-LEUBA: Just a question and 20 first I'd like to inform you that we, the members, we 21 ask a lot of questions and we interrupt a lot, so you 22 know that. So I'm not sure if you are the correct person 23 to ask this, but is this a program which is specific 24 to Seabrook or is this a more generic issue? Is the 25 staff considering it in other plants?
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23 1 And I'm thinking the ASR, the S stands for 2 silica, and most concrete is done with limestone. Is 3 that the answer? Is Seabrook the only plant that used 4 silica hydrates?
5 MR. BURTON: I can say that as far as the 6 nuclear industry, I believe, and correct me if I'm 7 wrong, I believe that Seabrook is the only nuclear plant 8 that has found this problem, although my understanding 9 is that it is an issue in other areas such as, I guess, 10 transportation, but we do have some of our technical 11 folks here. I don't know the extent to which it applies 12 to other things beyond what we're seen. I don't know 13 if -
14 MEMBER MARCH-LEUBA: So the other question 15 is you don't believe it's a generic issue, but was there 16 a generic letter issued to make sure that every other 17 plant was aware of the problem?
18 MR. DONOGHUE: No, this is Joe Donoghue.
19 No, we didn't issue a generic letter on this, and this 20 is a plant specific program that was put together.
21 There is continuing research that I think you're going 22 to hear about today. I think in his opening remarks, 23 Mr. McCartney mentioned their connection with INPO, 24 so the industry is aware of the issue, but this is -
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24 1 to hear this from the staff's presentation, this is 2 the first plant that observed ASR and this is the only 3 plant that I know of that has experienced it to the 4 extent that it could affect operability, and that's 5 what we're addressing here, so other plants have not 6 experienced it to that extent.
7 MEMBER MARCH-LEUBA: I'm thinking from the 8 point of view of physics, not - I mean, you need two 9 things for this to happen. You need to be close to 10 the sea to have salty water in your basement and have 11 used concrete that is segregated with granite.
12 MR. DONOGHUE: So Angie, one of our experts 13 who you're going to hear from later today, can add to 14 my, to our answers.
15 MS. BUFORD: Sure, when the ASR issue was 16 discovered at Seabrook, the NRC staff did issue an 17 information notice which didn't require licensees to 18 provide the NRC with written feedback, but it did 19 require that licensees consider the potential for ASR, 20 and so per the process for dispositioning information 21 notices, that goes into the corrective action program, 22 and then our resident inspectors inspect to make sure 23 that the licensees have adequately considered it.
24 MEMBER MARCH-LEUBA: Excellent, so you 25 would have held the ball and considered it on a generic NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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25 1 basis and discounted it. Thank you.
2 CHAIRMAN SKILLMAN: So NextEra is up.
3 Yes, sir?
4 MR. McCARTNEY: Thank you, Mr. Chairman.
5 So I have with me today Mr. Mike Collins. He's our 6 engineering director at the Seabrook Station. Mr. Ken 7 Brown is our licensing manager. Mr. Ed Carley, Ed is 8 our program manager for license renewal. And behind 9 you is Ms. Jackie Hulbert, and Jackie is our program 10 engineer for the ASR program.
11 Before I turn it over to the team for some 12 technical discussion, I'd like to bring your attention 13 to a little about the nuclear excellence model at 14 NextEra Energy.
15 This is a model of how we use to govern 16 our operation within our fleet. It's been in our 17 protocol since 2008. It's based on a set of core 18 principles and values that have never changed. They've 19 been the same since we introduced the model.
20 You'll see at the first top value on the left, 21 it's the, we conduct all activities with a deep respect 22 for nuclear safety. This is the foundation of how we 23 operate our fleet and our enterprise.
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26 1 and you'll see through our discussion, everything that 2 we talk about in our structures monitoring program is 3 subject to our appendix B corrective action program.
4 It gets audited through our own internal 5 audit program. It's subject to audit by our nuclear 6 oversight committee. It also reports out to our 7 corporate oversight, nuclear oversight committee that 8 reports to our board of directors.
9 We also focus heavily on prevention and 10 detection, and if we can spend 80 percent of our time 11 in prevention and detection, we can find issues at the 12 early onset and deal with them quickly so that the 13 actions that we have to take at that point are relatively 14 small and manageable and easy.
15 When we get into correcting space, we're 16 now having to correct a larger issue, so we want to 17 focus heavily, 80 percent of our time, in prevention 18 and detection, and this is the foundation of how we've 19 operated our fleet since 2008 and we'll continue to 20 do so.
21 CHAIRMAN SKILLMAN: Eric, let me ask this 22 question, and I'm imagining Dr. Rempe's opening 23 question. You're a learning organization. You just 24 communicated that your vision for your company is to 25 jump on issues early and prevent them from becoming NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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27 1 worse. Why then did it take from 2010 to 2014 to really 2 get a grip?
3 MEMBER REMPE: And could I even go a bit 4 further? Wasn't it because of an NRC inspection that 5 the next indicator in 2014 was identified? And the 6 reason that I'm again raising this now is because I 7 want to have the concern addressed that you're now 8 looking for other places where something could occur.
9 It was known that ASR expansion could cause 10 buildings, to place different loads on buildings and 11 have the walls deform, and that was what caused, my 12 understanding is, the seal to quit functioning as it 13 should. Is my question clear what I'm trying to say?
14 MR. McCARTNEY: I think your question is 15 clear and I think that through the course of the 16 technical discussion today, we'll probably answer a 17 number of those questions.
18 But one of the things that is a bit unique 19 about the application of ASR at Seabrook is the small 20 growth model. Much of the science involved with ASR 21 was recognizing an early rapid growth period. The 22 testing that we did early on during construction looked 23 for fast growth ASR.
24 I think the team will speak to that in a 25 lot more detail and a lot more technically than I'm NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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28 1 able to, but that, I believe, is the foundation that 2 will speak a bit to that time lag that you asked your 3 question about, Dr. Rempe.
4 MEMBER REMPE: Thank you.
5 CHAIRMAN SKILLMAN: Eric, thank you.
6 Please proceed.
7 MR. McCARTNEY: Okay, thank you, and I'd 8 like now to turn it over to our technical team and Ms.
9 Hulbert will come up and I'll leave back to the back 10 of the room.
11 MR. BROWNE: Thank you, Eric, and thank 12 you, Mr. Chairman. I'm Ken Browne, licensing manager 13 for Seabrook Station. I've been at Seabrook for 28 14 years.
15 I've held positions in operations, 16 including a senior reactor operator's license, varying 17 positions in the control room up through ops director, 18 several years in accredited training, and then the last 19 three years, I've been involved as a regulatory 20 compliance and project management sponsor for the 21 alkali-silica reaction project at Seabrook.
22 We've prepared a very comprehensive 23 presentation for you today. I believe it will address 24 the Committee's requests and concerns that you 25 articulated at the beginning of the meeting.
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29 1 Just a bit of background, since Seabrook's 2 last presentation at the ACRS Subcommittee, NextEra 3 and its specialty contractors have been engaged in 4 industry leading research in establishing a safe, 5 reliable method for understanding the effects of ASR 6 and also how it affects concrete and safety-related 7 structures.
8 CHAIRMAN SKILLMAN: Let the record show 9 that that last interaction with the ACRS was in 2012.
10 MR. BROWNE: That is correct.
11 CHAIRMAN SKILLMAN: It's been six years.
12 MR. BROWNE: That's correct.
13 CHAIRMAN SKILLMAN: And I'm not assigning 14 any pejorative connotation to that. I'm just saying 15 it's been a while since we've had you here to explain 16 what you're doing.
17 MR. BROWNE: It has been a while, yes, sir.
18 CHAIRMAN SKILLMAN: Thank you, okay.
19 MR. BROWNE: And at the time, we had spoken 20 about our large-scale test program which we had just 21 been initiating at the University of Texas, which was 22 to perform disruptive testing on large-scale beams done 23 with specimens that were representative of Seabrook's 24 structures.
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30 1 the large-scale testing would provide data about the 2 structural capacity of ASR-affected structures at 3 Seabrook, which as we all know, has significant 4 reinforcement.
5 We had since completed that large-scale 6 testing and it has demonstrated that there is no loss 7 of structural capacity for levels of ASR expansion 8 beyond that presently observed at Seabrook. The 9 results of the large-scale programs have been 10 incorporated into our structures monitoring program 11 and into evaluations of ASR-affected structures, and 12 as part of today's presentation, we will discuss in 13 detail how we determined that ASR conditions at Seabrook 14 are within the bounds of the Texas program.
15 Another change since our presentation is 16 that we've expanded the ASR project to include the 17 monitoring of building displacement and deformation 18 caused for ASR-related expansion.
19 As noted, over the past few years, we began 20 to recognize that certain susceptible areas in the plant 21 had shown relative movement due to ASR expansion. This 22 was evident to us in components like seismic gaps, flex 23 conduits, and we do have some photographs of that as 24 part of our presentation, and in some cases, instrument 25 tubing which had become misaligned.
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31 1 At that point, we enlisted the services 2 of Simpson, Gumpertz, and Heger out of Boston, who 3 performed inspection and analysis of these effected 4 buildings to ensure that the ASR-affected displacement 5 would not alter Seabrook's compliance with its design 6 code margins.
7 As data is integrated and continues to be 8 integrated from monitoring these buildings, we will 9 continue to update these evaluations throughout the 10 period of extended operation.
11 MEMBER REMPE: So this is, I guess, a good 12 place. You clearly have identified some buildings.
13 Are you looking for other locations that you have not 14 yet identified? I think there's feedback.
15 Okay, that's what I was concerned about 16 because, you know, what's happened in the past has 17 happened, but I want to make sure you're looking at 18 other locations that have not been identified. Thank 19 you.
20 MR. BROWNE: Yes, Doctor, we do have the 21 extensive walk down program that's been in place for 22 several years, and we have that as built into our 23 presentation, our extended condition, the structural 24 analysis, and where we stand currently for evaluation 25 of those structures.
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32 1 MEMBER REMPE: Thank you.
2 CHAIRMAN SKILLMAN: If I can ask, what is 3 the connection between that walk down program and the 4 entry of data into your corrective action program?
5 MR. BROWNE: Maybe Jackie Hulbert may be 6 better to answer that one, but right now, the walk down 7 data is entered into the CAP as part of the program 8 and we'll demonstrate. We have a couple of slides later 9 on that talks about our structures monitoring program 10 and just some of the tooling we use to make sure that 11 we've captured that by building and we're able to have 12 it all in one place so we understand what's going on 13 in the building.
14 CHAIRMAN SKILLMAN: Okay, thank you.
15 MR. SCHULTZ: Just a question, there is 16 some impression that the NRC's audits have found the 17 structural deformation in certain locations in the 18 plant. Is that the case or is it just an instance where 19 it's an area of the plant once identified in the NRC 20 audit and what is the circumstance there?
21 I'm talking about 2014, the audits that 22 were performed then. It appeared from the audit report 23 that the NRC found elements of structural deformation 24 before the licensee did.
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33 1 you're talking about, Dr. Schultz, is our, and you'll 2 hear about it here, is the containment enclosure 3 building.
4 It was noted by a junior resident at the 5 time that there was, from memory, there was a fire seal 6 or a seismic gap seal that had pulled away from the 7 structure and it was recognized, you know, credit given 8 to the inspector that brought that to our attention, 9 and that is really what led us down the road to 10 understanding more about how ASR was affecting 11 deformation on the structures, so, yes, it was 12 identified by the NRC at that point.
13 MR. SCHULTZ: And that lesson has affected 14 your program that you have in place today?
15 MR. BROWNE: Absolutely, and we'll talk 16 more about that in subsequent material. Regarding 17 regulatory transmittal over the last several years, 18 we have used the information from the Texas test 19 programs to also prepare two important licensing 20 actions for Seabrook.
21 We've submitted a license amendment 22 request, as Mr. Burton has noted, since relevant design 23 codes that Seabrook was built with did not consider 24 the loads resulting from alkali-silica reaction, and 25 we'll talk about that extensively in our presentation, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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34 1 and that amendment covers the methodology for 2 evaluating ASR-affected seismic CAT 1 structures at 3 Seabrook.
4 This methodology uses the results of the 5 large-scale testing program to determine the structural 6 capacity of concrete structures at Seabrook and defines 7 the analytical methodology used to evaluate these 8 structures.
9 The methodology also includes monitoring 10 to ensure that structures remain within limits of the 11 large-scale testing program and within its design 12 margins as established in the structures analysis.
13 We have also enhanced our license renewal 14 aging management program for alkali-silica reaction, 15 which was the program we first presented back in 2012, 16 to account for the results of the large-scale testing 17 program.
18 I'm going to move to introduce our team 19 on the next several slides. We've brought a number 20 of NextEra individuals and also our specialty 21 engineering firms that have assisted us over the years 22 with getting to this point.
23 I won't go into specific details of 24 introductions on our contractors, but I will just go 25 through the highlight, the slides, and the team leads NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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35 1 just to move us into the presentation, Mr. Chairman.
2 The NextEra representatives are, as Eric 3 has mentioned, here, and all of these will be speaking 4 at some point during today's presentation.
5 We also have, excuse me, we also have MPR 6 Associates who is a well-known industry expert. They 7 are a multidisciplinary specialty firm with roots in 8 the nuclear power industry, and John Simons is here 9 leading that team from MPR.
10 We have Simpson, Gumpertz and Heger, which 11 we're lucky to have, out of the Boston office, which 12 is in close proximity to Seabrook, and they're a 13 national engineering firm that designs, investigates, 14 and rehabilitates structures, and Dr. Said Bolourchi 15 is here leading that team and he'll be making a large 16 part of our presentation today.
17 And lastly, we have some distinguished 18 technical consultants, notably Dr. Bayrak, who ran our 19 program at the University of Texas at Austin, and Dr.
20 Bruce Ellingwood of Colorado State University.
21 I'm going to turn the presentation over 22 to Mike Collins, our engineering director, to walk us 23 through the background and introduction to ASR from 24 an engineering perspective.
25 MR. COLLINS: Good morning, my name is NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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36 1 Michael Collins and I'm the Director of Engineering 2 at Seabrook Station. I have 37 years' experience in 3 the nuclear industry, 17 years with Stone and Webster 4 Engineering, with new build construction, and also 5 continuing services at operating facilities, and 20 6 years at Seabrook Station, the last four-and-a-half 7 years in which I functioned as the Director of 8 Engineering.
9 So my part of the presentation here will 10 be the background of our station and also lay out how 11 we're going to proceed today with our discussions and 12 presentations.
13 Seabrook Station is a single unit 14 Westinghouse four-loop pressurized water reactor with 15 a General Electric turbine -
16 OPERATOR: The conference is now in silent 17 mode.
18 MR. COLLINS: We're located in the town 19 of Seabrook, New Hampshire, two miles west of the 20 Atlantic Ocean, approximately two miles north of the 21 Massachusetts state line, and 15 miles south of the 22 Maine state line.
23 Our reactor is housed in a steel-lined 24 reinforced concrete containment structure which is 25 enclosed by a reinforced concrete containment enclosure NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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37 1 structure. This containment enclosure building, 2 otherwise known at the station as the CEB, is a structure 3 that actually encapsulates our containment building.
4 5 So if you're onsite and you look at the 6 rounded structures at many facilities, it is in fact 7 a containment building. That's not the case at 8 Seabrook Station. That's our containment enclosure 9 building.
10 MEMBER RICCARDELLA: Excuse me, is that 11 building also the missile shield for the containment?
12 MR. COLLINS: The containment still has 13 its analysis for missile shields, and we do have 14 protection of missile shields that we'll discuss in 15 one aspect of the presentation, to protect penetrations 16 going through that area from the containment enclosure 17 structure to containment itself.
18 MEMBER RICCARDELLA: But does the CEB also 19 function as a missile shield?
20 MR. COLLINS: That is correct.
21 MEMBER RICCARDELLA: Okay, thank you.
22 MR. COLLINS: We're at 3648 megawatt 23 thermal power and 1250 net megawatts electric. The 24 Atlantic Ocean is our ultimate heat sink. The seismic 25 category one mechanical draft cooling tower provides NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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38 1 additional safe shutdown capability for the ultimate 2 heat sink. Next slide, please.
3 This is an aerial view of our station, both 4 the unit controlled area and our protected area.
5 Again, we're two miles inland west of the open Atlantic 6 Ocean. Next slide, please.
7 And this is the - as originally designed, 8 this station was to be a two unit site. It's broken 9 down, which we call the 50-yard line, down the middle 10 of the station. This side of the station is Unit 2, 11 which construction on that Unit 2 was terminated in 12 1984. The construction permit expired in 1988. That 13 is outside our protected area as it stands.
14 Some of our major buildings that can be 15 seen is our containment structure, our fuel storage 16 building, our service water pump house, our primary 17 auxiliary building, the seismic cat one safety-related 18 cooling, mechanical draft cooling tower that was just 19 mentioned, our residual heat sink removal vaults, and 20 our controlled building which houses our emergency 21 diesel generators.
22 So just quickly going through our licensing 23 timeline, construction permit July 1986, zero power 24 operating license October 1986, low power operating 25 license in 1989, our full power operating license March NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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39 1 1990, and as was stated earlier, our commercial 2 operation August 1990, operating license transfer to 3 Florida Power and Light, now NextEra energy November 4 2002.
5 Our stretch power operate the 3587 6 megawatts was in February 2005. We went through a zero 7 power recapture which the NRC then issued amendment 8 105 to the Seabrook facility operating license 9 extending the expiration date from October 17, 2026 10 to March 15, 2030.
11 CHAIRMAN SKILLMAN: Michael, what was the 12 action undertaken for the stretch power upgrade? What 13 did you do there?
14 MR. COLLINS: It certainly wasn't the 15 magnitude of the large station's extended power to 16 operate. We placed some rotating elements in our 17 condensate pumps. We didn't replace any feedwater 18 heaters.
19 We didn't replace any feedwater pumps.
20 Rather minimal, we fit our MSRs from a two pass to a 21 four pass. It wasn't as large, again, as our facilities 22 down south such as St. Lucie and Turkey Point 23 encountered.
24 CHAIRMAN SKILLMAN: Did you change your 25 fuel or did you change your operating cycle length?
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40 1 MR. COLLINS: Yes, fuel design was changed 2 through an 18-month design of our fuel cycle.
3 CHAIRMAN SKILLMAN: Okay, thank you.
4 MEMBER RICCARDELLA: What was the prior 5 thermal power limit?
6 MR. BROWNE: The original licensed thermal 7 power was 3411 megawatts.
8 MR. COLLINS: Again, we had a slight more 9 increase in power with a two percent uncertainty up 10 rate with instrument uncertainties we took advantage 11 of. Our license reapplication was submitted in May 12 2010 and our present operating license expires March 13 15, 2030.
14 The present status of the ASR effort at 15 Seabrook Station, to date, we've completed a 16 comprehensive effort to conduct large-scale testing 17 to understand the structural implications of ASR. From 18 that, we've developed methodology for evaluation of 19 ASR-affected structures.
20 We're evaluating, presently evaluating all 21 our seismic category one structures. There's 26 of 22 those structures. And we're developing a monitoring 23 strategy of ASR-affected concrete and associated system 24 structures and components.
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41 1 seismic category structures and comply with the 2 proposed licensing basis as amended in the LAR, and 3 we have identified areas where modifications to 4 structures are underway and required.
5 And as stated earlier, we're actively 6 engaged with NEI, EPRI, and other working groups to 7 make sure we're actively tracking developments and any 8 other ASR research not conducted by ourselves.
9 NextEra Energy Seabrook has implemented 10 an effective program for evaluating and managing the 11 impacts of ASR on effected concrete structures and 12 associated system structures and components.
13 CHAIRMAN SKILLMAN: Michael, you 14 mentioned the numeric 26 structures. Is that 26 that 15 are seismic category one or is 26 the number of the 16 ASR-affected structures?
17 MR. COLLINS: 26 that are seismically 18 category one, and each one of those are being evaluated 19 via analysis as impacted by ASR as individual 20 structures.
21 CHAIRMAN SKILLMAN: Is that what the 22 station calls the ASR scope?
23 MR. COLLINS: That would be fair to say.
24 We are looking at some other structures that aren't 25 considered category one structures, but are part of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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42 1 our license renewal activity, and those will be included 2 in the ASR aging management program.
3 CHAIRMAN SKILLMAN: Yes, sir, thank you.
4 MEMBER RICCARDELLA: So I spent some time 5 reviewing the detailed evaluation of the CEB, which 6 was cited as an example of a stage three evaluation.
7 MR. COLLINS: Yes, sir.
8 MEMBER RICCARDELLA: I'm just curious as 9 to the scheduling of similar evaluations on these other 10 26 structures. Are any of the others complete? Are 11 they going to be complete prior to the period of extended 12 operation?
13 MR. COLLINS: Absolutely is the answer to 14 that question, but we'll certainly go into more depth 15 as far as the amount of structures that are evaluated.
16 Presently 19 of those structures have their 17 evaluations completed and eight structures are 18 underway. Approximately half of those are in draft 19 format at this point.
20 MEMBER RICCARDELLA: Okay, thank you.
21 MR. SCHULTZ: Will you present more 22 detail, Mike? Will you present more detail on the 23 schedule related to that later today?
24 MR. COLLINS: Yes, sir.
25 MR. SCHULTZ: Thank you.
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43 1 MR. COLLINS: You know, the buildings were 2 prioritized for evaluation with regards to the extent 3 of ASR presently identified in those buildings. The 4 point of discovery would be early for those buildings.
5 MEMBER KIRCHNER: Michael, could you give 6 us some examples of modifications to structures? How 7 extensive are these modifications and their relative 8 importance?
9 MR. COLLINS: Yes, sir, one of the 10 modifications that has taken place is there's missile 11 shield blocks that are attached to our containment 12 enclosure building as you go out towards the outside 13 of the containment structure that, with regards to 14 missile analysis, protect some of our very important 15 penetrations that go from the Seabrook into the 16 containment building.
17 With the relative movement of the 18 containment enclosure building, one of those missile 19 shield blocks actually came in contact with the ID of 20 the containment structure. With that, we remediated 21 that by reestablishing the three-inch gap between that 22 missile shield block and the outside of our containment.
23 MEMBER KIRCHNER: Thank you.
24 CHAIRMAN SKILLMAN: Michael, when you 25 mentioned the 26 buildings that are categorized, those NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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44 1 are the category one, two, and three in accordance with 2 some of your documentation?
3 MR. COLLINS: You'll see through our 4 presentation today we have several different means of 5 categorizing the extent of ASR and how we specifically 6 analyzed those buildings, so those 26 structures are 7 broken up into those three categories which we'll 8 present when we do our detailed discussion of our 9 analysis.
10 CHAIRMAN SKILLMAN: Thank you.
11 MR. COLLINS: Next slide, please. So the 12 purpose of our presentation today is to describe the 13 comprehensive approach for addressing ASR at Seabrook 14 station, provide an overview of the technical basis 15 for ASR, of the ASR management approach which certainly 16 includes our large-scale testing, and from that, the 17 methodology for evaluating ASR-affected structures, 18 and then most importantly for the long term of our 19 station, summarize implementation of the structures 20 monitoring program for aging management of the 21 ASR-affected structures. Next slide, please.
22 Our presentation outline will include my 23 present presentation of ASR background, our approach 24 to addressing ASR, our technical basis for our ASR 25 management approach via the large-scale testing NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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45 1 programs, and the structural evaluation methodology 2 of ASR-affected structures, and our implementation of 3 the ASR management approach, our structures monitoring 4 program, and present the status of our relevant 5 licensing actions, our license amendment request, and 6 our licensing renewal application. We will then 7 provide conclusions and closing remarks.
8 The background of ASR at Seabrook Station, 9 in 2009 during the Seabrook license renewal process, 10 it was identified that aggressiveness of groundwater 11 chemistry on concrete structures in contact with 12 groundwater and soil needed to be determined. Testing 13 was performed, and in August 2010, Seabrook confirmed 14 the presence of ASR degradation of concrete in below 15 grade walls of several category one structures.
16 The identified material properties that 17 were impacts, which again we'll go into detail as we 18 go forward with our presentation, was a loss of 19 compressive strength, loss of tensile strength, and 20 reduction of the modulus of elasticity.
21 What ASR is, ASR occurs in concrete when 22 reactive silica in the aggregate reacts with hydroxyl 23 ions and alkali ions in the pour solution, the cement.
24 Hydroxyl ions detach the silica anions which then 25 combine with the alkali ions. The reaction produces NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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46 1 an alkali-silica gel that expands as it absorbs 2 moisture, exerting tensile stress on the surrounding 3 concrete and results in the cracking that we'll discuss 4 in detail in our presentation today.
5 What we have behind myself here on the shelf 6 here are several samples of slices of core bores we 7 have taken, you know, to give you a feel for the size 8 of the cracking that we're discussing in the concrete 9 pour.
10 We also have an example of the extensometer 11 which is the device that we're using to measure through 12 wall expansion, which we'll call the Z direction 13 expansion of our concrete walls, and we have an optical 14 device that we use for our crack mapping, and also 15 finally petrography slides for the thin slices of the 16 material they take for the petrographer to look at to 17 determine what level of ASR we have in that core sample.
18 You're free to look at that during the breaks. If 19 you have any questions, please talk to one of the 20 individuals supporting this presentation.
21 So these are pictures looking at 22 ASR-affected structures outside of Seabrook Station.
23 These photos will look very familiar to the pattern 24 cracking that has been seen at our station and also 25 through the country's infrastructure. As you will hear NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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47 1 today, ASR is an aging effect and has been known in 2 the concrete industry since the 1930s.
3 CHAIRMAN SKILLMAN: Before you change that 4 image, this is not Seabrook. This is another place.
5 MR. COLLINS: That is correct.
6 CHAIRMAN SKILLMAN: What other places are 7 we looking at, please?
8 MR. COLLINS: These are samples. I don't 9 know if SG&H can help me with that. They're most likely 10 bridge abutments. That's correct, bridge abutments.
11 CHAIRMAN SKILLMAN: Bridge abutments in 12 Walla Walla, Washington?
13 MR. CARLEY: Commonwealth of 14 Massachusetts.
15 CHAIRMAN SKILLMAN: In the Commonwealth 16 of Massachusetts, bridges that do what?
17 MR. COLLINS: Matt, can you help me with 18 this?
19 CHAIRMAN SKILLMAN: Do they support 20 automobile traffic? Do they support railroad traffic, 21 both, neither?
22 MR. SHERMAN: This is Matthew Sherman with 23 Simpson, Gumpertz, and Heger. These were photographs 24 that we've taken on other projects where we were working 25 for the Massachusetts Department of Transportation.
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48 1 There is retaining walls there that are supporting 2 backfill on the upper right.
3 There are bridge abutments, I believe, on 4 the lower left and lower right. So we're doing the 5 same types of observations and measurements. So 6 they're carrying traffic. It's well known. ASR is 7 well known in the transportation industry.
8 CHAIRMAN SKILLMAN: Okay, those white 9 buttons on the lower left image, those are extensometer 10 penetrations out of that monolith?
11 MR. COLLINS: Matt, I'll take it from here.
12 No, sir, they're not. Those are pins that are used 13 to measure implant expansion in the X and Y direction.
14 Those will be addressed in detail from both the 15 large-scale testing program and also our structures 16 monitoring program.
17 CHAIRMAN SKILLMAN: So you're using these 18 devices in places other than at Seabrook to determine 19 the extent to which this concrete is expanding?
20 MR. COLLINS: Yes, sir.
21 CHAIRMAN SKILLMAN: Okay.
22 MEMBER RICCARDELLA: Yeah, I have a 23 related question. So you have two pictures of 24 individuals, it looks like, with calipers measuring 25 crack width. Are those the, are they applying like NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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49 1 the CI, the crack index method?
2 MR. COLLINS: Those are the pin to pin 3 measurements that are used in our component cracking.
4 MEMBER RICCARDELLA: Okay, so that's -
5 CHAIRMAN SKILLMAN: And the CCI?
6 MEMBER RICCARDELLA: And the CCI, so 7 that's not something that was just invented for 8 Seabrook. That's something that's fairly well used 9 in the concrete industry?
10 MR. COLLINS: That's correct, and you'll 11 see how we use that, although we looked at different 12 methods of what we were going to use for instrumentation 13 going forward, and that was developed during the 14 University of Texas large-scale testing. There will 15 be a section in our presentation on how we derived what 16 instrumentation we would use to track our ASR growth.
17 MEMBER RICCARDELLA: Thank you.
18 CHAIRMAN SKILLMAN: Were these images 19 taken only in the state of New Hampshire?
20 MR. COLLINS: Massachusetts, sir.
21 CHAIRMAN SKILLMAN: Oh, how about Maine?
22 MR. COLLINS: I don't have any pictures 23 from Maine.
24 CHAIRMAN SKILLMAN: If I went to Maine, 25 would I find stuff like that?
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50 1 MR. COLLINS: I would say yes.
2 CHAIRMAN SKILLMAN: And also in New 3 Hampshire?
4 MR. COLLINS: We don't want to leave New 5 Hampshire out. Yes, sir, you would find that also.
6 CHAIRMAN SKILLMAN: Thank you, okay.
7 MR. COLLINS: Next slide, please. So the 8 ASR background, causes of ASR, original plant 9 construction, preventive measures were taken during 10 plant construction to prevent the development of ASR.
11 We did aggregate, using aggregate reactivity testing 12 and we used low alkali cement.
13 Where we are today with the knowledge of 14 reactive, slow reactive, slow moving reactive 15 aggregate, the ASTMs that were used during original 16 plant construction were not effective in identifying 17 the aggregate that we had was slow reactive.
18 Today's dates, we use updated ASTMs that 19 are recommended in a modern test nuclear plants can 20 use for aggregate reactivity test data.
21 Current state of knowledge on this, ASTM 22 test methods used during plant construction were not 23 reliable as an effective means to identify slow reactive 24 aggregate, and also finally, limiting alkali content 25 of cement alone was not sufficient itself to prevent NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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51 1 the ASR phenomenon. Next slide, please.
2 So it was the visual identification of 3 pattern cracking in the 2009 time frame with the 4 identification of aggressive groundwater, which is 5 about 500 ppm chlorides, that led us to doing the 6 investigation in the walls, which led to the core bores 7 and petrography and the identification of ASR in our 8 walls.
9 MEMBER MARCH-LEUBA: So, Michael, for my 10 education again, is this an education with a bad 11 concrete mix that you bought 40 years ago, or is this 12 an issue with groundwater, or both?
13 MR. COLLINS: It's an issue with regards 14 to the aggregate we used in the construction of our 15 station.
16 MEMBER MARCH-LEUBA: Yeah, but what is the 17 source of the sodium? Is that groundwater or was it 18 in the concrete to start with?
19 MR. COLLINS: It was not in the concrete 20 to start with. We have not had any above that level 21 since 2011. The source of sodium could be as easy of 22 the rock salt we spread around the station in the winter.
23 It's not tied directly to us being on a marsh or being 24 close to the ocean, and then the issue of groundwater, 25 we'll go into that with a little more detail.
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52 1 We have buildings above grade subjected 2 to ambient humidity that have the same levels of ASR 3 as we do in the lower elevations that are impacted with 4 true wall groundwater, so we can't tie groundwater, 5 ASR directly to the presence of groundwater. It's 6 evident above grade and also below grade.
7 Again, we discussed this. This is again 8 one of the mechanisms we use which we'll discuss in 9 detail to monitor X, Y in plane expansion of the cracking 10 concrete.
11 So implications of ASR at the station, 12 you'll see in the upper right-hand corner, that's just 13 industry literature for expansion effects of ASR on 14 unreinforced concrete, so that data applies to the 15 investigation and the analysis that we've done for 16 unrestrained concrete structures which we'll, 17 unrestrained concrete cores that we'll discuss later 18 in our evaluation.
19 As I mentioned earlier, ASR impacts the 20 reduction of material properties and their effect on 21 structural capacity, again, compressive strength, 22 tensile strength, and modulus of elasticity.
23 CHAIRMAN SKILLMAN: Michael, please -
24 excuse me, go ahead.
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53 1 information that I have found, I observed that they 2 had a lot of cautions in the industry that just because 3 you don't see cracks, you need to be concerned about 4 structural deformation because it's below grade, and 5 obviously that's proven to have happened at Seabrook.
6 MR. COLLINS: Yes, it has. So thank you 7 for the lead in on effects of ASR expansion on structural 8 demands. That is being handled by our analysis we're 9 doing, and structural deformation as evident in this 10 station, you can see on the lower left.
11 That is reflecting relative movement 12 between structures, and then on the right, you'll see 13 those are electrical flex connections that are between 14 structures and reflecting relative movement between 15 the structures.
16 CHAIRMAN SKILLMAN: Michael, please explain 17 what the lower left image is portraying.
18 MR. COLLINS: The lower left image is the 19 concrete structure has pulled away from a metal, we 20 call it a kick plate, in that area of the building.
21 MEMBER MARCH-LEUBA: Sorry, I didn't get 22 that. The part moved a couple of inches to the left.
23 Is that what you're saying?
24 MR. COLLINS: That's correct.
25 CHAIRMAN SKILLMAN: Thank you.
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54 1 MR. SCHULTZ: Michael, the graph 2 information, is that showing Seabrook data, testing 3 data?
4 MR. COLLINS: It is not. It's just 5 ourselves just reflecting that what we'll present today 6 with regards to unreinforced concrete is in line with 7 industry practices.
8 MR. SCHULTZ: So we'll see more later?
9 MR. COLLINS: Yes, you will.
10 MR. SCHULTZ: Thank you.
11 MR. COLLINS: So we're going to become very 12 familiar with this slide through the presentations 13 we're going to make today. This flow chart is the 14 layout and explains the integrated approach that 15 NextEra Seabrook has developed in response to the 16 identification of ASR in our concrete structures.
17 All of the ASR related efforts fit and flow 18 together, and all results, conclusions, lessons learned 19 are incorporated into the structures monitoring 20 program.
21 Before we go into each section of our 22 detailed discussions today, we'll discuss each one of 23 these blocks shown on this flow diagram, and the 24 respective block will be presented in the front of that 25 discussion, so as you go through, you can piece our NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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55 1 process together.
2 MEMBER BALLINGER: This may not be the 3 right point to ask this question, but in all of the 4 presentations, I don't see explicit comment on any 5 interaction between the Seabrook folks and the other 6 ASR related programs that are undergoing funded by DOE.
7 NIST has a big program that's looking at concrete 8 degradation. Are you guys connected or following those 9 programs?
10 MR. COLLINS: We are knowledgeable and are 11 following. We haven't been fully engaged in those 12 programs.
13 MEMBER BALLINGER: Because they're very 14 extensive in terms of full scale testing and a lot of 15 it's being done at the University of Texas. Tennessee?
16 I thought Texas as well, but anyway, okay, so you 17 haven't been?
18 MR. COLLINS: Well, again, we're 19 knowledgeable of the activities, but we haven't had 20 teams associated with those activities.
21 So with regards to just a quick overview 22 of each one of the aspects of our overall approach, 23 we have the large-scale testing conclusions, our input 24 into our structures monitoring program. Large-scale 25 testing conclusions are input to our structural NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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56 1 evaluations. ASR load factors have been derived for 2 use in our structural analysis.
3 Our evaluation methodology and guidance 4 was developed out of both the ASR load factor 5 development and also our large-scale testing. Our 6 field data is used to feed into our structural 7 evaluation of our 26 seismic category one buildings, 8 and structural evaluation results then feed into our 9 ongoing monitoring and evaluation effort.
10 MEMBER RICCARDELLA: Tell me a little bit 11 about the ASR load factors. What are we referring to 12 there, please?
13 MR. COLLINS: I can't explain that because 14 it's over my head. You will be - I am honest on that.
15 That will be discussed in-depth by SG&H in their 16 presentation.
17 MEMBER RICCARDELLA: Thank you. I was 18 just trying to understand whether those are safety 19 factors applied to the ASR or factors that are projected 20 or allowing for projection of additional ASR in the 21 future.
22 MR. COLLINS: Those are derived safety 23 factors for the analysis.
24 MEMBER RICCARDELLA: Okay, thank you.
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57 1 answer that, but I wouldn't do it justice.
2 MEMBER RICCARDELLA: Okay.
3 CHAIRMAN SKILLMAN: Michael, let me ask 4 this question. The image that showed the displacement 5 raises in my mind my own years of being involved. Not 6 all buildings' displacements would be of concern, but 7 there are some places where a change, where a 8 displacement could be a very large concern.
9 For example, up in your spent fuel pool, 10 if you got some walk on your north/south walls, you 11 could take your fuel handling gear out of plumb or out 12 of track and out of trolley.
13 If you have movement in your primary shield 14 in your reactor cavity, you can offset the points of 15 loading for the reactor coolant systems, support for 16 the reactor vessel for your reactor coolant pumps and 17 for their capability to resist seismic loads or to be 18 aligned properly.
19 Would you say something, please, about how 20 the plumbers at the site and the operators at the site 21 really viewed differential movement relating to 22 operability and to the integrity of your license?
23 MR. COLLINS: Absolutely, so via our 24 structures monitoring program, we all monitoring all 25 of the structures at this point. That's fully NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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58 1 developed. We actually do our target surveys in the 2 fuel storage building to make sure relative movement 3 isn't impacting any of those structures. There's been 4 no, as you explained, tell-tale signs in that structure 5 of issues.
6 The containment building, there's been no 7 ASR identified within the containment building. We'll 8 talk a little later. There's been some very small areas 9 on the outside wall of containment that have been 10 addressed with ASR.
11 We've also, to have more eyes in the field, 12 we have trained both the operators and the engineering 13 staff on the aspects of ASR and what to be looking for 14 so that a daily operator round, he is looking for those, 15 so again, we will identify the issues early and put 16 them into the structures monitoring program.
17 If they're not conforming and considered 18 degraded, an AR is written and they're put into our 19 corrective action program. That gives the shift 20 manager a look at it right out of the gate to make an 21 initial operability call on that item. So all hands 22 are on deck for the station looking for the impacts 23 of ASR on our structures.
24 CHAIRMAN SKILLMAN: Will you talk about 25 this later today?
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59 1 MR. COLLINS: We'll talk about it later 2 today with regards to Jackie Hulbert's presentation 3 of our structures monitoring program.
4 CHAIRMAN SKILLMAN: Okay, thank you, all 5 right.
6 MEMBER REMPE: But just to clarify, did 7 you say, "We are now monitoring all structures on the 8 site for deformation and movement," not just the 9 category one or the ASR-affected structures, but all 10 structures? Is that what I heard you say?
11 MR. COLLINS: I believe we're focusing on 12 the category one structures at this point.
13 MS. HULBERT: We are, but our structures 14 monitoring program as well encompasses all structures, 15 so we look for that pattern cracking under, like, the 16 maintenance rule portion.
17 MEMBER REMPE: But deformation, just 18 pattern cracking or -
19 MS. HULBERT: So deformation, we're 20 monitoring seismic category one structures.
21 MEMBER REMPE: Just the category one, 22 okay. Thank you.
23 MEMBER MARCH-LEUBA: For my own education, 24 this expansion, is it overnight or is it, I mean, is 25 it a meter a year, or you go home on a Friday and Monday NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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60 1 you show up and it's moved two inches?
2 MR. COLLINS: No, sir, the progression of 3 ASR is very slow moving.
4 MEMBER MARCH-LEUBA: Okay, so if you have 5 a decent -
6 MR. COLLINS: Years.
7 MEMBER MARCH-LEUBA: - program to look for 8 it, you will see it?
9 MR. COLLINS: Yes, sir.
10 MEMBER MARCH-LEUBA: Okay.
11 MR. BROWNE: And Mr. Chairman, if I could 12 revisit your question, as a result of our root cause 13 for the containment enclosure building deformation that 14 we discuss, one of the actions coming out of that 15 corrective action was to, we had a multi-discipline 16 team which also had operators in it that did a, I think 17 the number was plant engineering guideline 98, which 18 is the comprehensive multidisciplinary walk down of 19 the site, to identify things like you're mentioning, 20 like conduit deformation, pipes that may be offset in 21 their support, safety loaded structures. So 22 that was all captured out of the initial root cause 23 coming out of CEB and then dispositioned, and it's also 24 a two-year requirement coming out of tech 98 as well, 25 but we'll talk about that as well.
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61 1 CHAIRMAN SKILLMAN: Thank you.
2 MR. SCHULTZ: Mike, you've had almost 10 3 years of experience with this now. When you say slow 4 moving, are we talking weeks, months, years, or does 5 that vary?
6 MR. COLLINS: We're talking decades.
7 MR. SCHULTZ: Thank you.
8 MEMBER DIMITRIJEVIC: But you have 9 identified, according to this, all of the potential 10 impact on plant systems and factors, right? So, and 11 you know what was potentially impacted on the safety 12 of the plant due to this, right? And did you use that 13 in prioritizing some of the problems?
14 MR. COLLINS: So we have used our walk down 15 data to prioritize the first buildings that went into 16 analysis. That's correct, and then again, the daily 17 walk downs of the building structures monitoring 18 program, if anything is new or identified as moving, 19 it goes into our corrective action system.
20 MEMBER DIMITRIJEVIC: Okay, but you're 21 having a comprehensive release of all the systems and 22 components that could be impacted?
23 MR. COLLINS: Ms. Hulbert will show the 24 comprehensive database that we maintain for all 25 buildings and building areas and the observations in NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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62 1 those areas.
2 MEMBER DIMITRIJEVIC: And you have 3 comprehensive risk assessment as I am familiar that 4 Seabrook has, and I know you have a daily observation 5 too on the daily activities, so did this in any, did 6 you do any risk analysis on this potential impact on 7 the systems and components?
8 MR. COLLINS: As far, I mean, certainly 9 if we find something that is impacting a system 10 structure or component in a degraded way, that risk 11 analysis happens at what we call T-zero, right away 12 for its impact on the station.
13 MEMBER DIMITRIJEVIC: Okay, so there is 14 nothing that you can say is in progress that can 15 potentially damage this pipe, or these cable trays, 16 or whatever connections or anything?
17 MR. COLLINS: So, you know, to be honest, 18 we have observed items that aren't perfectly straight 19 in a pipe sleeve that have pulled away from walls, but 20 those are being evaluated on a case by case basis and 21 included in the overall program. Next slide please.
22 So just in conclusion before I turn it over 23 for the full presentations that are going to be made 24 today, the large-scale test program, we have determined 25 that there is no adverse impact on ASR on structural NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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63 1 capacity within the test limits identified via the 2 University of Texas Program. Limits have been 3 established for monitoring of plant structures. Our 4 evaluation methodology define process that considers 5 the impact on ASR on both structural capacity and 6 structural demands of the respective structures.
7 Structure evaluations demonstrate the 8 seismic category one structures comply with the 9 licensing basis as amended by the LAR, and then 10 structures monitoring comprehensive program addresses 11 ASR expansion, building deformation, and impact on 12 system structures and components.
13 NextEra Energy has implemented an 14 effective program for evaluating and maintaining the 15 impacts of ASR on effected concrete structures and 16 associated system structures and components. I'll now 17 turn over the program back to Mr. Browne.
18 MR. BROWNE: Thank you, Mike. Mr.
19 Chairman, that concludes our opening remarks and 20 initial presentation for NextEra, and at this point, 21 the next section is a closed section, so that concludes 22 our remarks.
23 CHAIRMAN SKILLMAN: Kenneth, thank you 24 very much. Ladies and gentlemen, we are going to take 25 a 10-minute break. We will return at four minutes to NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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64 1 10:00 on that clock. We are going to stay on schedule 2 and we are in recess for 10 minutes.
3 (Whereupon, the above-entitled matter went 4 off the record at 9:46 a.m. and resumed at 1:17 p.m.)
5 CHAIRMAN SKILLMAN: Ladies and gentlemen, 6 let's restart our meeting. We are back in session.
7 We are in the open session and we turn the meeting over 8 to SGH. Gentlemen, please proceed.
9 MR. BROWNE: Thank you, Mr. Chairman. I'm 10 going to turn it over to Dr. Said Bolourchi who is going 11 to lead us through the SGH portion of the presentation.
12 CHAIRMAN SKILLMAN: Yes, sir, thank you.
13 DR. BOLOURCHI: Thank you very much. I'm 14 Said Bolourchi. I'm the senior principle at Simpson 15 Gumpertz & Heger in Boston.
16 I have worked in the nuclear industry since 17 the very early 1980s and I started my work with John 18 Bloom and Associates and work on many of the, started 19 at Diablo Canyon and then continue with many of the 20 other plant.
21 I will be representing the methodology 22 for the ASR affected structure. And in this 23 presentation Mr. Glenn Bell and Matt Sherman, both 24 senior principals from Simpson Gumpertz & Heger, will 25 be helping me along with Bruce Ellingwood that will NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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65 1 be introduced.
2 Each person when they come in they will 3 introduce their background for your information. Next 4 slide. The goal is to present the consistent and 5 repeatable methodology that can be applied to all 6 Category 1 structures at Seabrook.
7 And, but the basic principle in structural 8 engineering, I'm sorry that many of you may not be in 9 structural engineering. But the basic premise is the 10 equation I put on the slide.
11 The structural capacity is the strength 12 of the number that it can resist the load should be 13 greater than total load. That is the concept.
14 In the morning session it was discussed 15 that the effect of ASR will not reduce the code 16 capacities and therefore, we can apply the code equation 17 for calculating the capacity. And in doing that we 18 will keep having reliability of the code into the 19 evaluation.
20 There also, they discussed about the change 21 in the stiffness because of the pre-stressing.
22 Therefore, now on the right hand side in the load that 23 was originally designed for this structure, for all 24 the structures at Seabrook the ASR was not part of a 25 load that was listed in the UFSAR.
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66 1 Therefore, as part of this part we will 2 define the load associated with ASR and the load factor 3 associated with that. And then also we will discuss 4 the field data to identify what is the status of the 5 ASR for each individual building.
6 And that we will discuss as part of this 7 methodology. And then we will discuss the modeling 8 procedure to make sure that we will capture what was 9 observed in larger scale testing which includes the 10 pre-stressing effect.
11 Next slide. In the morning some of the 12 questions was answered. But why are we calculating 13 the demand in the structure.
14 If you start with the unreinforced concrete 15 and you expose it to ASR the number will expand but 16 it will not produce any measurable load that will affect 17 the structure.
18 But if the structure is restrained, such 19 as this structure, all the structures in Seabrook, then 20 when it wants to expand the resistance to that expansion 21 will produce imposed load on that structure and that 22 load has to be accounted.
23 And that resistance can come from a number 24 of places. It can come from reinforcement, doesn't 25 let it grow therefore it is internal balance between NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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67 1 the concrete and steel but the steel, it will produce 2 its loads.
3 Other segment of a structure if there is 4 one part of the structure is expanded and the other 5 part is not the transition between that will see a lot 6 of load in the ASR portion and in the area which is 7 not in the ASR portion where you see all this load or 8 if it's adjacent structures or a part that they are 9 holding.
10 Therefore, as a whole if you have, if you 11 are resisting this expansion then you will produce load.
12 And this load can be significant therefore it should 13 be considered in total evaluation on the right hand 14 side of the equation that we said it needs to be done.
15 Therefore, ASR affected structure must be 16 evaluated even if you don't see deformation as such.
17 But it needs to be evaluated. Go ahead, next.
18 Under methodology again we wanted to make 19 sure we calculated all Category 1 structures to make 20 sure that they will meet the UFSAR as amended by LAR.
21 And in the structural evaluation methodology there 22 are two basic segments that we need to discuss.
23 One is the ASR loading and loads factor 24 to make sure that we maintain the code reliability that 25 it was intended. The other is a document that can be NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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68 1 applied to all structures uniformly for all of that.
2 And this methodology will provide detailed 3 collection of the data and also evaluation of all 4 seismic Category 1 structures. Go ahead. And then 5 now I want to introduce Glenn Bell for discussing the 6 ASR load factors.
7 MR. BELL: Good afternoon, everyone. My 8 name is Glenn Bell. I am senior principal and chairman 9 of Simpson Gumpertz & Heger. I have 43 years' 10 experience in the design, evaluation and rehabilitation 11 of structures of all types.
12 I'm going to address the preparation of 13 the load factors for ASR loading, which as the graphic 14 on the screen shows is input into the structural 15 evaluation methodology. To my right is Professor, Dr.
16 Bruce Ellingwood.
17 Dr. Ellingwood was our independent 18 reviewer for this portion of the work. He is an eminent 19 authority on the theory of structural safety and 20 reliability and has done groundbreaking work in that 21 area not only in the nuclear industry but in structural 22 engineering in general.
23 And he'll have some comments at the end 24 of my presentation. But he reviewed and validated this 25 part of our work.
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69 1 As Dr. Bolourchi mentioned, the overall 2 objective of our methodology is to supplement the design 3 loads used in the original plant design with new ASR 4 loads. And the objective is to do that in a way that 5 maintains that level of structural performance implicit 6 in the original design criteria codes and standards.
7 So we are maintaining all of the loads and 8 load combinations of the original Seabrook design but 9 introducing new ASR loads into those load combinations.
10 Next slide, please.
11 The containment building at Seabrook was 12 designed to the ASME Boil and Pressure Vessel Code, 13 Section 3, Division 2, 1975. All of the other seismic 14 Category 1 structures at the plant were designed to 15 ACI standard 318-71 version.
16 The ASME and ACI documents are based on 17 different design philosophies. ASME is based on 18 so-called allowable stress design which I will describe 19 while the ACI standard is based on so-called strength 20 design.
21 Why were different codes and criteria used 22 for different structures? The answer is that ACI 23 318-71 is principally concerned with strength, assuring 24 that the structure's strength is adequate which is 25 appropriate for all of the Category 1 structures at NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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70 1 Seabrook but the containment building.
2 The containment building on the other hand 3 serves the dual purpose not only of structural 4 containment but also containing the radiological 5 consequences of a loss on cooling accident. So the 6 ASME code requires loading capacity criteria that 7 assure these dual purposes through provisions not 8 contained in the ACI standard.
9 In particular, the ASME code limits 10 stresses in concrete and steel reinforcing to ensure 11 the containment buildings function as a pressure 12 vessel. I go into this detail because the approaches 13 for the design standards and approaches to load factors 14 are different because of these dual purposes.
15 So I'm going to take these one at a time.
16 Next slide, please. So let's start with the ASME code, 17 again applied to the containment building. For the 18 containment building the program --
19 CHAIRMAN SKILLMAN: Glenn, let me jump in 20 here just for a second.
21 MR. BELL: Yes, sure.
22 CHAIRMAN SKILLMAN: And let me address my 23 question to Kenneth please. So I'm going to go back 24 to being a landowner within three or four miles of this 25 site.
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71 1 And I am witnessing NextEra building a 2 varsity team of extraordinarily qualified 3 professionals to defend ASR. The question is, why did 4 NextEra not specifically choose this team but why did 5 NextEra go to a strong outside consulting firm, if you 6 will, as opposed to using a group that might be located 7 in Portsmouth, New Hampshire or Manchester, New 8 Hampshire or someone real, real close to the farms and 9 to the land near the plant?
10 MR. BROWNE: Yes, I'll try to answer your 11 question. Obviously it's a complex issue. We were 12 first in the industry in needing to deal with this.
13 SGH is, I would say they are somewhat close 14 because they are out of Boston and I mentioned that 15 earlier that we are fortunate that we have the access 16 to this expertise, you know, literally an hour away.
17 We've had virtually a constant presence 18 from them on site since we started addressing the issue.
19 I'm not sure if that answers your question. But I 20 do respect that it's certainly bringing that type of 21 technology home to New Hampshire and having that locally 22 is certainly an advantage.
23 But in this case the, just the level of 24 expertise we needed in order to understand a very 25 complex problem, first in the industry really drove NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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72 1 us to reach out for this kind of expertise.
2 CHAIRMAN SKILLMAN: Fair enough. I just 3 wanted to explore for those who might say why did you 4 find it necessary to go and get a varsity team from 5 over there versus next door.
6 I think you're saying they're really not 7 that far away. They're just down in Boston and they 8 bring an expertise that is essential for this unique 9 phenomenon that this facility is experiencing.
10 MR. BROWNE: That's well characterized.
11 I agree.
12 CHAIRMAN SKILLMAN: Thank you, please 13 proceed.
14 MR. SCHULTZ: Ken, you mentioned that 15 they've been on site since the problem began. Can you 16 characterize that more deeply?
17 MR. BROWNE: Yes, Matt Sherman will talk 18 here shortly after Glenn Bell and Liying who is one 19 of our inspectors who is in the audience with us 20 virtually is on site most days and she's been performing 21 virtually all of our surface inspections for the plant.
22 She does all of our CCI measurements. And 23 so that takes several days per week of, you know, of 24 her time. So they have really helped us develop the 25 program to where it is right now.
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73 1 DR. BOLOURCHI: We already have seven 2 batch inspector in the field and almost there is no 3 week that we don't have people there since 2010.
4 CHAIRMAN SKILLMAN: Glenn, I interrupted 5 you and I apologize. Let's proceed.
6 MR. BELL: No apology necessary, sir. So 7 we're starting with the containment building under the 8 ASME code. For the containment building Matt Sherman 9 is going to describe our field program in some detail 10 following me.
11 Our work there included crack index 12 measurements at four grids but very extensive visual 13 survey employing rope access. That field survey showed 14 that in the containment building there was only limited 15 localized ASR locations on the exterior surface of the 16 containment building.
17 And I'll show you a graphic in a few slides 18 from now of the location and the extent of that. So 19 we started with a very conservative initial screening 20 approach in our view of the CB, the containment 21 building.
22 The intent was to do this initial 23 conservative screening and if the analysis did not 24 demonstrate the structure's adequacy according to the 25 criteria that we would conduct further field NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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74 1 measurements, reduce the uncertainty and rerun the 2 analysis.
3 Fortunately, the structure passed the 4 initial conservative screening. Next slide, please.
5 As I mentioned earlier, the ASME code is based on 6 allowable stress design.
7 So it's primary objective is to limit 8 stresses in the concrete and steel reinforcement. And 9 the ASME code requires code checking under so-called 10 service and load conditions and factored load 11 conditions.
12 Service load conditions are those that 13 apply to scenarios of normal operation of the plant 14 which are expected to occur frequently over the life 15 of the structure. Concrete stresses under these 16 scenarios are kept well below the concrete's ultimate 17 compressive strength and well below the yield strength 18 of the reinforcement.
19 Factored load conditions, however, apply 20 to more severe scenarios that include extreme 21 conditions that could include failure of the reactor 22 cooling system and/or environmental conditions that 23 are considered to be upper bound for the site.
24 In this case the permitted stresses are 25 higher than they are for service load conditions. But NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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75 1 they are still below the concrete compressive strength 2 and below the steel yield strength.
3 There is one exception to the statement 4 that I just made is that some local steel yielding is 5 permitted under factor load conditions when temperature 6 gradients are considered in the analysis. Next slide, 7 please.
8 So the question was asked earlier exactly 9 what load factors are. And this slide describes that.
10 Load factors along with partial safety factors are 11 key to assuring the intended structural performance.
12 As Dr. Bolourchi mentioned earlier, our 13 primary objective in structural engineering is to 14 assure that the structure has adequate capacity to the 15 load effects imposed on it. That is the capacity must 16 equal or exceed the load effects.
17 That capacity we are concerned with in 18 allowable stress design is assured through limitations 19 on stresses. The effects of the loads represented on 20 the right hand side of the equation are typically from 21 multiple sources that can include dead load, live load, 22 wind, earthquake, temperature, et cetera.
23 These multiple sources are represented by 24 the S subscript I terms on the right hand side of the 25 equation. And in the case of our present exercise we NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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76 1 are also introducing ASR as a new loading condition.
2 The terms alpha I in front of the SI load 3 effects are the load factors. These are the load 4 factors. There are different load factors for various 5 types of loads in combinations of loads that codes 6 prescribe.
7 The purpose of the load factors is to 8 account for the variability of the actual loads from 9 the values used in design and to assure that the overall 10 required reliability, r margin of the safety of the 11 structure is achieved.
12 In allowable stress design the capacity 13 side of the equation on the left is determined by an 14 allowable stress f sub a which cannot be exceeded.
15 The allowable stress is held below a certain critical 16 stress, F sub cr, by applying a partial factor of safety 17 K to the critical stress and K is less than one.
18 So in terms of overall factor safety the 19 K factor and the alpha i's produce an overall factor 20 of safety against exceeding the allowable stresses.
21 The loads and load combinations represented by the ASME 22 code are deterministic.
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77 1 performance rather is assured under various scenarios 2 of normal and extreme loading that were posited by the 3 code drafters.
4 In the ASME code most of the load factors 5 are 1.0, although some are 1.25 and 1.5 for severe 6 environmental or abnormal conditions. An example of 7 the application of a load factor higher than one is 8 in the operating basis earthquake when it is applied 9 to extreme and abnormal conditions.
10 Because the operational basis earthquake 11 is a relatively frequently occurring event it needs 12 to be scaled up by some factor larger than one to 13 represent an extreme condition. On the other hand, 14 the safe shutdown earthquake which posits a very extreme 15 condition of seismicity, seismic accelerations uses 16 a load factor of one. Next slide, please.
17 MEMBER CORRADINI: So then for ASR, I think 18 Pete had asked that early on or you had asked somebody.
19 So what is alpha, to work your simple equation 20 backwards is alpha set to essentially make the allowable 21 force equal to the load?
22 MR. BELL: No.
23 MEMBER CORRADINI: Or you're looking for 24 a margin given in alpha?
25 MR. BELL: Yes, you're looking for a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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78 1 margin.
2 MEMBER CORRADINI: So in ASR's case you're 3 going to use some additional larger than one value with 4 the ASR loading?
5 MR. BELL: There's a linkage between the 6 severity of the loading and the alpha factor that you 7 use. The more extreme the loading the lower the load 8 factor needs to be to give you the margin that you need.
9 And, excuse me, and in most cases, in almost 10 all cases in the ASME code the load factors are 1.0 11 along with an approach that targets an extreme value 12 of loading.
13 MEMBER CORRADINI: Okay.
14 MR. BELL: Okay. Which is actually a 15 segue to the next slide. So consistent with this, next 16 slide, please. Consistent with this our approach is 17 to develop ASR loads that have a very small likelihood 18 of exceedance and to use an ASR load factor of one.
19 Next slide, please. This describes how 20 we developed the ASR loads. In our structural 21 methodology we applied ASR loading to structures by 22 defining four zones of ASR severity according to this 23 graphic.
24 And this is similar but not, this is similar 25 both in the ASME application and the ACI application.
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79 1 Zone 1 which is the lowest level of ASR expansion is 2 from a cracking index of near zero to .5 millimeters 3 per meter.
4 Zone 2 is from .5 to one. Zone 3, one to 5 two and Zone 4 over two. In the case of the containment 6 building, as I mentioned earlier, we have only a limited 7 amount of ASR and that all falls within Zone 1 where 8 it does occur.
9 And so I've only highlighted with a picture 10 the box showing Zone 1 here. So our methodology for 11 an extreme and conservative application of ASR is to 12 apply to the entirety of the entire zone an ASR strain 13 corresponding to the upper limit of that zone.
14 And in the stage one analyses we increase 15 that upper limit by another factor of 1.25. So the 16 practice of applying 1.25 times the maximum limit to 17 the entire zone is conservative.
18 In this case with Zone 1 ranging from CI 19 to .1 to .5, we apply a value of .6 across the entire 20 zone.
21 CHAIRMAN SKILLMAN: Glenn, that is, at 22 least it seems to me to be a decision that's driven 23 by an assumption of the thoroughness of the inspection 24 of the containment building. You've said there is 25 little or no cracking or very little limited cracking.
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80 1 MR. BELL: Correct.
2 CHAIRMAN SKILLMAN: How should we judge, 3 if you will, the thoroughness of that inspection?
4 That's a big building.
5 MR. BELL: We have done extensive visual 6 survey all over the building that included rope access 7 all the way to the top and found only limited ASR across 8 the containment building. And the next graphic, if 9 I may, help to answer that question will illustrate 10 that.
11 CHAIRMAN SKILLMAN: I'll be happy to wait 12 until the next slide.
13 MEMBER RICCARDELLA: First is why are we 14 using the term CI here rather than CCI?
15 MR. BELL: I should explain that CI and 16 CCI we're using interchangeably with respect to the 17 application of the ASR loads.
18 MEMBER RICCARDELLA: Okay. And also I 19 did, I haven't seen the containment building analysis.
20 But I have reviewed the CEB analysis.
21 And I thought I saw in that you are 22 averaging the CI readings over regions, that you weren't 23 just picking the maximum individual value.
24 MR. BELL: You are correction application 25 to the CEB. And I'm going to go on, that's the different NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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81 1 approach that I was talking about in the ACI code and 2 I'll explain how we dealt with that there.
3 MEMBER RICCARDELLA: So for the 4 containment you're using the absolute --
5 MR. BELL: Maximum in the zone.
6 MEMBER RICCARDELLA: -- that you found?
7 MR. BELL: Maximum in the zone augmented 8 by 25 percent.
9 MEMBER RICCARDELLA: Okay. There were 10 zones and regions though in the CEB.
11 MR. BELL: We simply worked with zones in 12 the CEB.
13 MEMBER RICCARDELLA: So the containment 14 was all one region you're saying?
15 MR. BELL: If I could go to the next slide 16 that might help clarify both questions, okay. This 17 is a schematic illustration of the extent of ASR from 18 the extensive visual surveys in the containment 19 building.
20 You see a band of Zone 1 ASR that runs around 21 the base of the cylinder just above the foundation level 22 for a height of about six feet. There is also a band 23 below the equipment hatch shown schematically there.
24 And one other patch that is not shown 25 because it occurs on the back side is a three foot by NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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82 1 eight foot section of, I'm going to call it suspected 2 ASR because we were conservative in our interpretation 3 of the cracking in that particular area.
4 And that occurs at an elevation of 68 feet 5 which is higher than the level in the equipment hatch 6 that you see here roughly on the far side. So you can 7 see the vast majority of the CEB has no ASR and even 8 where it occurs it's only within Zone 1.
9 CHAIRMAN SKILLMAN: How is that captured 10 in your documentation so that a generation to come can 11 review this documentation and have a strong starting 12 point?
13 MR. BELL: We have an extensive log of all 14 of the field work and the photographs associated with 15 that tagged to particular locations over the building.
16 All of that is summarized in all of our reports running 17 all the way down to the application of loads in our 18 finite element analysis for the containment building.
19 So it's very thoroughly documented, the 20 dates, the locations, photographic documentation, et 21 cetera.
22 CHAIRMAN SKILLMAN: Thank you.
23 MR. BELL: Yes.
24 MEMBER REMPE: So I have a question that 25 will show my ignorance in this methodology. But from NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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83 1 the material I read they emphasized the point that a 2 lot of times there's below grade cracking that imposes 3 a load.
4 And yet your presentation emphasized that 5 you used this cracking measurement to base your load 6 on. How do you account for these loads that you can't 7 see?
8 MR. BELL: In this particular case if there 9 was, and we looked at this case, if there was expansion 10 to the foundation that would actually alleviate the 11 loads on the cylinder. We ran the analysis both ways.
12 MEMBER REMPE: Okay, good.
13 MR. BELL: And we only reported the worst 14 case which was the assumption of no ASR or no cracking, 15 no expansion in the foundation. But that's a more 16 severe condition because the foundation if it doesn't 17 expand tends to restrain the expansion in the cylinder 18 from the ASR.
19 MEMBER REMPE: Okay, thank you.
20 MR. BELL: Sure.
21 MEMBER BROWN: For the uninitiated again, 22 another one of my dumb questions. Why is it so local 23 as opposed to more, sorry about that. Why is it so 24 locally located as opposed to more uniformly 25 distributed?
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84 1 I mean it seems to be these very unique 2 bands over this entire thing it's all concrete.
3 MR. BELL: As others have said today and 4 I think will continue to say over the course of the 5 day the presence of ASR has some drivers. But there's 6 a lot of randomness to the process.
7 But one of the many drivers is humidity, 8 high humidity. There was a point in time when there 9 was a wet zone on top of the foundation near the base 10 of the cylinder.
11 That's been dried out now but our 12 presumption is that the humidity associated with that 13 drove that band of ASR down at the foundation level.
14 We also know at one point in time there was some leakage 15 in the equipment hatch tunnel between the CEB and the 16 equipment hatch that probably drove that band of ASR 17 down that you see just below the equipment hatch.
18 MEMBER BROWN: Okay, thank you very much.
19 MR. BELL: Sure.
20 MEMBER RICCARDELLA: Where is grade on 21 this?
22 MR. BELL: I'm sorry.
23 MEMBER RICCARDELLA: Where is grade, what 24 level is grade, right at the foundation?
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85 1 near the equipment hatch.
2 DR. BOLOURCHI: Equipment hatch.
3 MR. BELL: Any other questions before we 4 --
5 MEMBER CORRADINI: Yes, just so we're all 6 on the same page. This is the containment --
7 MR. BELL: Correct.
8 MEMBER CORRADINI: -- which is inside the 9 CEB.
10 MR. BELL: Right.
11 MEMBER CORRADINI: And the difference in 12 distance between the two that have allowed the visual 13 inspection is about two or three feet?
14 DR. BOLOURCHI: Four and a half feet.
15 MR. BELL: Four and a half feet.
16 MEMBER CORRADINI: Okay.
17 MEMBER RICCARDELLA: What was the three 18 inch clearance that I read?
19 MR. BELL: I think that was reference to 20 a seismic expansion joint earlier.
21 MEMBER RICCARDELLA: Okay.
22 PARTICIPANT: That was actually the missile 23 shield.
24 MEMBER RICCARDELLA: There's three feet 25 between.
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86 1 MR. BELL: There's three feet, four and 2 a half feet, I think, annulus between the CB and the 3 CEB.
4 MEMBER RICCARDELLA: Thank you.
5 MR. BELL: So next slide, please, 6 summarizes the approach to load factors in the 7 containment building. And next slide, please, Ken, 8 thank you.
9 We selected a conservative approach to 10 loads and load combinations by taking the highest level 11 of strain in each zone and applying it to the entire 12 zone and augmenting that by another 25 percent margin.
13 Also we know that the large-scale testing 14 program that was described earlier demonstrated on 15 average the cracking index measurements conservatively 16 predict ASR strain and furthermore the literature shows 17 that ASR strains measured at the surface of the concrete 18 significantly overpredict the strains at the 19 reinforcement depth which is the depth that we're most 20 concerned with when it comes to detecting stresses and 21 reinforcement and so forth.
22 So for each load combination for the CB 23 by the ASME code we have applied a conservative value 24 of ASR strain in combination with a load factor of one.
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87 1 other than the containment building, ACI 318-71.
2 This, as I said earlier, uses a different 3 approach to assuring structural performance than the 4 ASME code and that impacts the methodology that we use 5 for determining load factors. Next slide, please.
6 These structures, as I mentioned, were 7 designed to the ACI standard 318-71 which takes the 8 ultimate strength design approach where the primary 9 objective is to assure adequate strength.
10 We check that strength through the code 11 equations which were mentioned earlier with respect 12 to the large-scale testing program.
13 MEMBER CORRADINI: May I just back you up?
14 MR. BELL: Absolutely.
15 MEMBER CORRADINI: Is the CEB this or ASME?
16 MR. BELL: This. Only the CB uses ASME.
17 All of the other Category 1 structures --
18 MEMBER CORRADINI: Only the containment 19 uses ASME?
20 MR. BELL: Did I misspeak? Only the 21 containment, excuse me.
22 MEMBER CORRADINI: The CEB uses this?
23 MR. BELL: The CEB uses this, yes.
24 MEMBER CORRADINI: Thank you.
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88 1 strength with the code equations that were described 2 earlier. The ACI code also includes secondary, 3 so-called serviceability checks that are made under 4 less extreme loading conditions.
5 But we're primarily concerned here with 6 assuring adequate strength. Next slide, please. This 7 graphic is very similar to the one that I showed for 8 the ASME code where we are looking to assure that 9 capacity exceeds the load effects.
10 The general construct of the right hand 11 side of the equation the load effect side is similar 12 to the application of the ASME code. The capacity is 13 determined a bit differently again, because we're 14 looking to assure adequate strength rather than 15 limiting stresses.
16 So the factor R, is the nominal strength 17 capacity determined by code equations and it is modified 18 by a partial safety factor fee which is less than one.
19 Now contrary to the ASME code where most of the load 20 factors are 1.0, in the ACI code they generally fall 21 between 1.4 and 1.7.
22 In the case of the UFSAR the application 23 of the operating basis earthquake goes up to 1.9 and 24 there are some numbers smaller than 1.4 for different 25 load combinations. But the point here is that most NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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89 1 of them fall in the range of 1.4 to 1.7 significantly 2 higher than the 1.0 in the ASME code.
3 MEMBER CORRADINI: I'm sorry that I keep 4 on asking this stuff. So if I made a plot of this phi 5 R is always larger than F sub a?
6 In other words, there's got to be 7 equivalence in terms of the loading. So the way I think 8 of it is your phi R capacity term is higher than F sub 9 a.
10 MR. BELL: As a general prospect we're 11 looking at a more extreme condition of structural 12 loading, exactly, yes.
13 MEMBER CORRADINI: Okay, all right, thank 14 you.
15 MR. BELL: Yes. Next slide, please.
16 CHAIRMAN SKILLMAN: Before you change.
17 From where do you chose the phi?
18 MR. BELL: I'm going to come to that. But 19 actually if you could bear with me for one more slide 20 or a couple more slides I think that will answer your 21 question. Next slide, please.
22 So since the 1980s the underlying approach 23 to design of concrete structures to the ACI standards 24 and many others has been based on probabilistic concepts 25 of structural reliability. These standards use a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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90 1 quantitative approach to variations in capacity and 2 load effects to achieve a numerical targeted level of 3 reliability.
4 Reliability here is defined as the 5 probability of not exceeding an acceptable measure of 6 structural performance. While the 1971 version of ACI 7 318 was not based on probabilistic concepts work was 8 underway in the mid to late 1970s to define a 9 probabilistic approach.
10 And a key project in laying the groundwork 11 for a probability based structure reliability was 12 undertaken at the Natural Bureau of Standards, now NIST 13 of course. And the leader of that program was Dr. Bruce 14 Ellingwood who was then a research engineer at the NBS.
15 In their work Ellingwood and his colleagues 16 were able to quantify the levels of reliability inherent 17 in the then existing design methods including ACI 18 318-71. So they sort of reverse engineered the 19 problem, if you will.
20 And they laid out an approach for what is 21 called load and resistance factor design going forward, 22 probabilistically based, reliability based 23 engineering. The work evaluated and his colleagues 24 were culminated in a report that is thumbnailed on the 25 left hand side here called Development of a Probability NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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91 1 Based Load Criterion for American National Standard 2 A58.
3 This report became the seminal document 4 in structural reliability implementation in codes and 5 standards and is a key reference in our approach to 6 developing ASR load factors for the ACI code for this 7 project.
8 Structural reliability in this context is 9 defined by a term beta reliability index. There's a 10 relationship between the probability of failure and 11 beta. The higher the beta the higher the probability 12 that the structure will remain safe.
13 The methodology to incorporate ASR effects 14 into this analysis employs the NBS study's findings 15 regarding the reliability inherent in ACI 318-71. The 16 NBS studies show the average reliability or beta for 17 various load combinations to be as shown in the slide 18 here.
19 That is for load combinations involving 20 static conditions basically gravity loads and lateral 21 earth pressure, a beta of 3.0. For load combinations 22 involving wind a beta of 2.5. For load combinations 23 involving the operating basis earthquake 1.75.
24 And we used these target reliabilities in 25 our methodology thus maintaining that level of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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92 1 reliability inherent in ACI 318-71. Next slide, 2 please.
3 So we used a similar zoning approach as 4 I described earlier for the ASME code. But we had very 5 extensive statistical data on cracking index 6 measurements for the plant. We had measurements, 216 7 measurements and 108 grids which we used for a 8 statistical analysis to feed into beta.
9 And we grouped those into the four zones 10 of severity shown here. Zone 1 being less than .5.
11 Zone 2, .5 to 1. Zone 3, one to two and Zone 4, anything 12 higher than two.
13 And for each zone we determined the ASR 14 strains from statistics gathered over the zones for 15 the entire plant. We mapped the four ASR severity zones 16 onto each structure and we applied in our loading an 17 ASR strain corresponding to the mean value of CI 18 measured in each zone with the application of a load 19 factor on top of that.
20 That addresses the question that I came 21 up earlier I think. And we applied that 22 probabilistically based determined load factor. Next 23 slide, please.
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93 1 and the sources of information. The target reliability 2 level of beta.
3 It is based on the NBS report, as I just 4 mentioned. The probability distribution of structural 5 resistance is based on the NBS report and out of that 6 come statistics about the resistance to answer your 7 question and also the phi factor, to directly answer 8 your question, comes right out of the ACI code.
9 But that phi factor needs to, the 10 probability distribution of structural resistance 11 needs to be consistent with the NBS report in order 12 for that phi factor to be appropriately applicable.
13 We gained the probability distribution of all of the 14 loads other than ASR based on the methodology of the 15 NBS report.
16 The probability distribution of the ASR 17 load effects we gained from the statistics measured 18 at the plant. And we also need to know the ratio of 19 ASR load effects to the total load effects, a factor 20 that we call k ASR and we found representative values 21 for each ASR zone in our calculation.
22 So these input variables go into a 23 calculation that finds the ASR load factor that results 24 in the target reliability level. Next slide, please.
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94 1 calculations to determine load factors. But for static 2 load factors for Zone 1, the ASR load factor is 2.0.
3 For Zones 2 to 4 it's 1.6. For wind, 1.7 4 for Zone 1. For Zones 2 to 4, 1.36. For the operating 5 basis earthquake, 1.3 for Zone 1. 1.04 for Zones 2 6 through 4.
7 A couple of comments on this. Number one, 8 these are simply the load factors that apply to the 9 ASR loads. All of the other loads in the combination 10 use the standard code load factors.
11 And you'll note here that the load factors 12 for Zones 2 through 4 are lower than those for Zone 13 1. The reason for that is that the coefficient of 14 variation of the CI statistics in Zone 1 is larger than 15 Zones 2 to 4.
16 And that has to do with the size of the 17 denominator, coefficient of variation being standard 18 deviation divided by the mean. So that's smaller 19 there.
20 There's two other footnotes. Per ACI 21 318-71 when you have load factors, load combinations 22 that involve differential settlement, create shrinkage 23 or temperature change these load factors may be reduced 24 by 25 percent, but they may not be less than one.
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95 1 load combinations involving very extreme values of say 2 shut down earthquake and tornado these are not 3 determined deterministically. They are, they are not 4 determined probabilistically.
5 They are determined deterministically with 6 a load factor of 1.0. I have a concluding slide that 7 perhaps I should pause here for questions before we 8 go to that.
9 MEMBER RICCARDELLA: You need to help me 10 with this table. Are you saying you used different 11 load factors on the ASR load when you combined them 12 with these other loads? Is that why there is a whole 13 table here?
14 MR. BELL: We used these load factors in 15 any of the equations that involve loads with ASR 16 loading. So these are the load factors applied to ASR.
17 A typical load combination will include 18 many factors, dead load, live load, possibly wind or 19 earthquake, et cetera. And now they always include 20 ASR load as well.
21 Each of those loads, individual loads has 22 its own load factor. These are the load factors that 23 we applied to the ASR loads in every combination.
24 MEMBER RICCARDELLA: In that specific 25 equation, in those specific loads?
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96 1 MR. BELL: Yes, that's correct.
2 MEMBER RICCARDELLA: But what about, I 3 mean, but don't you have combinations that would include 4 static plus wind?
5 MR. BELL: We do. And we included all of 6 those in the calculations that lead to the ultimate 7 reliability level data using the code prescribed load 8 factors for those loads that are code prescribed.
9 So we're adding here ASR loading to all 10 of those load combinations. A load that I have 11 described along with specific load factors just for 12 the ASR load. We don't change anything else.
13 MR. SCHULTZ: Glenn, could you walk 14 through one more time why the load factors for Zones 15 2 through 4 are lower than for Zone 1? These are, Zones 16 2 through 4, are those where the cracking index is larger 17 than in Zone 1.
18 MR. BELL: Right. So coefficient of 19 variation is standard deviation divided by the mean.
20 If you go to the next slide the mean in Zone 1 is very 21 small.
22 It ranges between zero and .1. The means 23 of all of the other zones are significantly larger.
24 That's the main driver.
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97 1 precision in the optical measurements in the very fine 2 cracks is probably not as high as it is, the wider the 3 crack the more precision that we have in the optical 4 measurements. So those two factors account for that.
5 MR. SCHULTZ: Okay. It's the level of 6 variation divided by --
7 MR. BELL: Yes, it's all in the variation, 8 yes.
9 MR. SCHULTZ: I can see that. Thank you.
10 MEMBER RICCARDELLA: The level of 11 variation in the measurements that you've made in the 12 field in a specific zone. Is that what you're, that's 13 what you're referring to, right?
14 MR. BELL: That and the fact that in 15 computing COV we're using a very small denominator for 16 Zone 1. But I have one more slide if --
17 MEMBER RICCARDELLA: I am still struggling 18 --
19 MR. BELL: Go ahead.
20 MEMBER RICCARDELLA: -- a little with 21 this. I mean, should the second row really be static 22 plus wind and the third row should be static plus wind 23 and also be --
24 MR. BELL: These are load combinations 25 that are principally static. They don't include wind.
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98 1 They can include dead load and by static we mean dead 2 load, live load, lateral earth pressure. The second 3 row are load combinations that involve wind, et cetera.
4 MEMBER RICCARDELLA: I understand now.
5 Okay, thank you.
6 MR. BELL: So our last slide, please.
7 Oops, no, that's correct, sorry. In conclusion, we 8 developed ASR load factors for both the ASME and the 9 ACI 318 approaches.
10 We used methods that are consistent with 11 the underlying philosophy of the original design 12 criteria. We used methods that are consistent with 13 the level of safety and reliability inherent in those 14 codes and standards.
15 And we took a comprehensive and 16 conservative approach at various decision points. And 17 with that I will turn it over to Dr. Ellingwood who 18 has some comments based on his review of the work that 19 I just presented.
20 CHAIRMAN SKILLMAN: Before you do that let 21 me ask a question to NextEra, to Kenneth. Kenneth, 22 if I'm, again I'm a citizen of New Hampshire, I live 23 six miles from this place, will the documentation that 24 defends this be available to me in a publicly releasable 25 form so I can take my calculator and my pencil and do NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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99 1 some calculating?
2 In other words, will there be a version 3 of this that is available to the citizens that are living 4 a couple miles from this facility?
5 MR. BROWNE: The license amendment request 6 and also the AMP are also, are submitted on the docket 7 for review. So, I guess, simplistically, yes.
8 CHAIRMAN SKILLMAN: Simplistically.
9 Does that mean --
10 MR. BROWNE: The proprietary version is 11 obviously redacted for --
12 CHAIRMAN SKILLMAN: I understand that.
13 Now is the not proprietary version of sufficient detail 14 that an interested and curious person could pretty much 15 come to the same conclusion that your consultant has 16 come to?
17 MR. BROWNE: The methodology document and 18 also the remaining calculations would need to be married 19 up with the license amendment request in order to come 20 to the same conclusions.
21 CHAIRMAN SKILLMAN: I would like you to 22 think about that just some lessons from what it took 23 to take a plant from not operable to being fully operable 24 given a local next door. We've also seen this, for 25 instance, at Davis-Besse, which was another 350 plant.
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100 1 And the question was can the public really 2 find a way to come to the same conclusion without going 3 through extraordinary efforts.
4 MR. BROWNE: No, I understand your comment 5 and several of your questions have been focused around 6 the fact that when you have difficult problems in our 7 industry they're often very difficult to, we obviously, 8 we work in a complex industry.
9 And it's a technology that sometimes can 10 be difficult to understand. And then when people don't 11 understand our industry due to the complexity they reach 12 a conclusion that's often adverse to safety.
13 So I understand your comment and we'll work 14 to --
15 CHAIRMAN SKILLMAN: You know, I'm a 50 year 16 veteran in this, actually a little bit more than that.
17 And what I've learned is the public is mighty smart.
18 MR. BROWNE: Absolutely.
19 CHAIRMAN SKILLMAN: And they are owed good 20 answers because one of the most important features we 21 have in nuclear is that we're open to the community.
22 And if the community can find their way to come to 23 almost the same conclusion without a lot of smoke and 24 mirrors the public gains a lot of confidence very 25 quickly.
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101 1 MR. BROWNE: No, I understand your 2 comment, we understand your comment at NextEra.
3 CHAIRMAN SKILLMAN: Okay, thank you.
4 Please proceed.
5 DR. ELLINGWOOD: Thank you, Glenn. I was 6 asked to perform an independent evaluation of the 7 calculations that the SGH team had made in support of 8 the load combinations and the load factors applied to 9 alkali silica reaction structural actions.
10 And in my judgment the conclusions that 11 they arrived at for the containment building and the 12 methods employed are consistent with, you know, the 13 load combinations that appear in Section 3, Division 14 2 of the ASME Boiler and Pressure Code which are in 15 fact deterministically based and historically done that 16 way.
17 For the Category 1 structures other than 18 containment, the procedures that they followed were 19 consistent with the procedures that we adopted in 20 developing the probability based load resistance 21 factors for American National Standard A58 which 22 subsequently have been adopted by all the model codes 23 in the United States material specifications and I might 24 add by some overseas code organizations as well.
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102 1 have been proposed for the load factors will achieve 2 the target reliabilities that Glenn had produced in 3 support of his recommendations. Thank you.
4 DR. BOLOURCHI: I would like to present 5 Matt Sherman to first come and discuss about the field 6 observations before we get to the actual methodology 7 document because we used this data in that.
8 MR. SHERMAN: Sure. Thank you very much.
9 My name is Matthew Sherman. I'm a senior principal 10 at Simpson Gumpertz & Heger.
11 As Dr. Bolourchi just mentioned we're going 12 to do a little bit of a jump ahead to the field data.
13 And we're going to talk about that before he comes 14 back and talks about how it all feeds into the structural 15 evaluation methodology.
16 We're doing that because it's, the 17 methodology document describes how the field data is 18 actually used in the analysis. And when Dr. Bolourchi 19 goes through that document he's going to use some 20 examples of how the field data feeds into the structural 21 evaluation methodology.
22 So if we tell you right now a little bit 23 ahead of time how we do the field data when it comes 24 along to talk about how it's used you can concentrate 25 on that part and we can keep kind of the simple NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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103 1 attainment of the data here first.
2 All right, so to reboot, I'm Matt Sherman.
3 I have about 25 years of experience in the civil 4 engineering world mostly in civil engineering 5 materials, construction, repair and testing.
6 I was the supervisor for the field data 7 acquisition portion of the work. Field data is used 8 extensively in the methodology document. It describes 9 very comprehensively how field data works in.
10 And it's really an integral component of 11 the structural evaluations that were done because it 12 works into an iterative process that lets us interact 13 with information, data and the results of analysis to 14 provide really a robust basis for the calculation.
15 Next slide, please. So if you think about 16 it the methodology document really describes this 17 evaluation process. It uses field data and provides 18 a framework, the methodology document provides a 19 framework for the overall, for the whole process.
20 And it really includes a cycle of analysis, 21 field data and an intelligent interpretation. This 22 is not a linear, one time process. It's a cycle where 23 we use the intelligent interpretation.
24 For example, field testing may include 25 observing crack patterns and measuring expansions.
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104 1 The analysis may be a finite element model that uses 2 some of that data.
3 And then the interpretation is an 4 intelligent comparison and backcheck of those, right.
5 So we have to match the models up with the data and 6 observer.
7 So it's an iterative process. So we start 8 with the observations. We might include measurements 9 and possibly some special testing. And it's done by 10 a team of people who are integrated. The field people 11 are integrated with the analysis team.
12 Next slide, please. So for this work we 13 can think of the field data as comprising three main 14 groups. There's, the first one is observations which 15 are kind of non-quantifiable information.
16 They're non-quantifiable. There are 17 measurements that are actually data that feed into the 18 analysis. And then there are sometimes specialty 19 testing that's used to supplement or to answer special 20 questions that arise during it.
21 All right, all of our work on the field 22 data work was done under full QA, under our full nuclear 23 QA program. All the field teams are two person teams 24 that include different degrees of peer checking to 25 review all the data.
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105 1 And then it's all evaluated through the 2 structural process. Next slide, please. So the field 3 work really starts with observations, right. This is 4 a walk down that guides and shapes the initial analysis 5 and field data gathering.
6 These walk downs are done with full plant 7 support and coordination for safety, access and also 8 as a source of historical knowledge for what's happened 9 in the plant and provide any background information 10 that's needed.
11 So remember that these observations 12 include information but not necessarily data that we 13 use. Next slide, please. So the observations give 14 us information on the extent of apparent ASR cracking 15 and it provides clues about other types of cracking 16 that may be present for other reasons.
17 Such as on the left here where you can see 18 these diagonal cracks that are highlighted in yellow 19 chalk. Those diagonal cracks are indicative of typical 20 shear forces.
21 You know, so we're using that information 22 and feeding into the overall analysis. The methodology 23 document describes in detail how the observed cracking 24 is incorporated into the analysis using pattern, type, 25 widths, all of that to aid in interpretation.
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106 1 This observation phase is a thinking 2 observation. It's a thinking operation. It's done 3 by people who are integrated into the overall team.
4 MEMBER MARCH-LEUBA: Quick question. Is 5 this Seabrook?
6 MR. SHERMAN: These are both at Seabrook, 7 yes.
8 MEMBER MARCH-LEUBA: Okay. So it is the 9 famous tunnel?
10 MR. SHERMAN: This is not the famous 11 tunnel. These are other locations.
12 MEMBER MARCH-LEUBA: And what, we're 13 talking a maximum of .5 or 5 millimeters per meter 14 expansion. What degree of expansion would say this 15 is?
16 MR. SHERMAN: This one I'm not sure of the 17 number for sure. I have a better example coming up 18 later on. This is low. This would be, the one on the 19 right hand side is down like what Glenn was talking 20 about.
21 MEMBER MARCH-LEUBA: I wonder about those 22 long cracks.
23 MR. SHERMAN: Those aren't ASR cracks.
24 Those are shear cracks, right so that's, the methodology 25 document describes how we do that. For the most part NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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107 1 we assume that they're ASR cracks and use that 2 conservatively.
3 There are occasions where, Said will get 4 into later on where the methodology document lets you 5 work through and understand that better. So sometimes 6 these observations will also include limited 7 measurements.
8 We'll go to the, there was an earlier 9 question, we go whenever we walk down an individual 10 structure or a room within a structure or a piece of 11 it, we go find the worst area to make measurements on 12 to help us frame what we're going to do there.
13 Again, it's a thinking operation. So 14 we'll do limited measurements to provide initial 15 assessments of severity and location. Really not as 16 a data source per se but to indicate what types of formal 17 measurements are required underneath the methodology 18 document.
19 It shows us what's required as follow up 20 work. We also, during these walk downs we also go to 21 areas and sound the representative surfaces to look 22 for any kind of, with hammers or chains to look for 23 drumming sounding areas or any weak sounding areas all 24 in accordance with the ACI 349.3 document which I was 25 just on the committee that revised.
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108 1 All right, next slide, please. So the 2 observations in walk down really let us incorporate 3 real world data. They let us bring that real world 4 information into our analysis.
5 This is needed because there is some degree 6 of cracking that is fundamental to reinforced concrete 7 behavior. That's in reinforced concrete 101, you know, 8 you have to crack to some degree to activate the 9 reinforcement.
10 That's because the concrete works mostly 11 in compression and it has to crack to let that 12 reinforcement work. And remember there are also other 13 sources of expected cracking such as when we do normal 14 pressure testing of the containment building or in 15 shrinkage causes cracking or anybody who walks around 16 who has a concrete basement knows that you have cracks 17 and look at your sidewalk when you're walking down.
18 So based on during the observations and 19 walk down we outline any cracks with chalk and identify 20 the patterns that may be unrelated to ASR within the 21 concrete. For example, on the left hand side again 22 those are those shear cracks that are highlighted in 23 yellow chalk.
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109 1 movement that could be related to expansion. For 2 example, the photo on the right shows the movement of 3 the conduit flex joints.
4 Movement direction and offset degree can 5 be used to calibrate the structural models, as Said 6 will describe in a minute. Now each one of these 7 structures, an earlier question about how, where the 8 data is available every structure that we go out has 9 a site visit report that's issued that has a full 10 breakdown of it and those are on the docket.
11 MR. SCHULTZ: Matthew, before you move on.
12 MR. SHERMAN: Yes, sir.
13 MR. SCHULTZ: The observations, I know 14 this is the first stage, if you will, of the 15 investigation. But you said that the, I just want to 16 check what you said, what I thought you said.
17 And that is this is done by a qualified 18 team that knows what they're looking for. It's a two 19 person team so that one is examining, the other is 20 checking that the observations are correct and so forth.
21 So this is not just an individual that's 22 out there looking to see what might happen. This is 23 all done as part of a documented observation by 24 qualified people.
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110 1 and testing protocol that we call on for each document 2 plus a test method that we have.
3 MR. SCHULTZ: And your procedures are 4 causing the team to document this examination in a 5 particular way.
6 MR. SHERMAN: Yes.
7 MR. SCHULTZ: So that when we look at the 8 reports or when anyone looks at the reports it was 9 mentioned earlier how do we know if the next generation 10 is going to know what happened when. This is the first 11 stage of that.
12 MR. SHERMAN: Correct. These will all 13 wrap up into a site visit report that is well documented 14 and the process is described in our test procedure and 15 in the ITP.
16 And that includes things about how you tier 17 and qualify inspectors. So there is basically a tiered 18 inspection program where you start off as almost as 19 a journeyman and then work your way up, you know, 20 apprentice work your way up to a journeyman to a senior.
21 MR. SCHULTZ: Appreciate that, thank you.
22 MEMBER MARCH-LEUBA: On this walk through 23 with procedure is it one time or is it going to be every 24 year?
25 MR. SHERMAN: These are all integrated.
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111 1 You'll hear more, these are integrated into the overall 2 structural monitoring program. It's not as simple as 3 just, there's not one answer because it depends on the 4 severity.
5 There are multiple tracks. There are some 6 tracks that are for the routine observations and 7 measurements and there are other tracks, parallel 8 tracks that relate to building analyses.
9 After the first time through actually 10 there's two parallel tracks. One that is based on the 11 results of the analysis, Said will tell us later on 12 about what we find, set some thresholds.
13 And there are other ones that are just part 14 of the overall parallel track that's for overall 15 monitoring. All right, next slide, please.
16 So the expansion measurements are done when 17 identified according to that methodology document.
18 These expansion measurements provide data that is 19 incorporated into the eventual evaluations.
20 If you think back to the earlier slides 21 on the overall testing program and Glenn's descriptions 22 of how we develop those load factors, this is the link 23 now. These expansion numbers are the link that 24 connects the actual plant to the results of the research 25 and the work done and to the statistical work that was NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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112 1 done to develop the load factors, right.
2 So the main group of these are direct 3 measures of expansion. Next slide. So we've seen this 4 already before. You've seen a little bit of some 5 background on the cracking index.
6 This is the most frequently used method 7 at Seabrook Station. Well over 100 locations are 8 currently being monitored with cracking indexes Glenn 9 just discussed in the background for the load factors.
10 As you previously heard about these are 11 measures of total cracking strain or a good way to 12 estimate total cracking strain to date. And it's 13 obtained from a crack mapping process where we do 14 quantitative measurements at individual cracks and 15 summation of crack widths along a set of lines.
16 I'll show an example of that in just a 17 moment. As we heard earlier this technique is based 18 on Federal Highway Administration documents that have 19 been developed for monitoring highway structures.
20 It's based on Institute of Structural 21 Engineer documents from overseas. It's a pretty well 22 established way of estimating crack strains.
23 These are used to estimate the expansion 24 reached to date by the ASR-affected concrete. And this 25 is the primary data that drives the structural NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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113 1 evaluations.
2 You can see here we have an example of one.
3 We make these, they are an optical measurement with 4 a magnifying loop and with a calibrated, inside there, 5 there is an optical reticle that helps, that lets you 6 measure the crack widths under magnification.
7 So with this you can measure it out to about 8 two one thousandths of an inch. All right, next slide, 9 please. So just as a quick recap if we imagine how 10 these measurements are done, this is a quick recap if 11 we imagine there are some cracks in a piece of concrete.
12 Next click. We draw lines. For 13 simplicity I'm going to show you one line. We draw 14 one line on the concrete and we measure where the crack, 15 the width of the crack where it crosses the line.
16 If you do the one click. And then we sum 17 those numbers together, next click and divide by the 18 length of the line. Gives an indication of total 19 strain, how much that concrete has gotten bigger.
20 That's very simple. In practice, if you 21 give me a next click, this is what an expansion grid 22 at the station looks like. All right, so it's 20 inches 23 by 30 inches.
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114 1 of those reference lines. The 20 by 30 inch grid size 2 is based on the Federal Highway Administration guide 3 document.
4 It lets us share those corner points to 5 economize the measurements and it balances the 6 directions pretty well. We get eight measurements in 7 one direction, nine in the opposite.
8 To give you an idea of the effort required 9 each one of those is a measurement of the crack widths 10 there. This type of grid will take somewhere on the 11 order of an hour to an hour and a half for a person 12 to do.
13 You wanted an example. This cracking 14 level was about 1.2 millimeters per meter.
15 CHAIRMAN SKILLMAN: Let me ask this on the 16 prior slide, Slide 31. How do you select length, L?
17 MR. SHERMAN: It actually ends up being 18 ten inches to let us combine it with the mechanical 19 strain gauges. In just a moment I'll show you that.
20 We actually used the same grids to do the expansion, 21 direct expansion measurements and the optical 22 measurements.
23 So by combining with ten inches it lets 24 us do dual purpose on those grids and leverage the data 25 that we get optically.
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115 1 MEMBER MARCH-LEUBA: This is just 2 curiosity. Can you go to the next slide? When I look 3 at this picture I don't see cracks. I mean when I look 4 at the sidewalk I see cracks, I see air in between.
5 This is just filled in with calcium 6 silicate gel. Is that what it is?
7 MR. SHERMAN: So the dark, those cracks 8 if you could read the pieces most of those are on the 9 order of two thousandths of an inch to maybe five 10 thousandths of an inch, those individual surface 11 opening cracks.
12 And the dark appearing material is actually 13 the alkali silica gel itself. So that wall is dry.
14 That's not moisture. That's the alkali silica gel.
15 MEMBER MARCH-LEUBA: I was reading during 16 lunch time. It's not alkali silicate. It's calcium 17 silicate.
18 MR. SHERMAN: Well it depends on what your 19 alkali is. Calcium is an alkali. That's an alkali.
20 It can be a sodium silicate gel as well. But we don't 21 have to go --
22 MEMBER MARCH-LEUBA: I read the Wikipedia 23 page. It's very informative. So I know --
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116 1 which is that alkali Dr. Bayrak talked about.
2 MEMBER MARCH-LEUBA: I recommend that you 3 read the Wikipedia page. That's the source of my 4 knowledge.
5 MR. SHERMAN: So if we jump to the next 6 slide please. So this is where the ten inch comes from.
7 So this is the mechanical strain gauges. So it's a 8 demountable mechanical strain gauge.
9 So we do these in addition to the cracking 10 index measurements. And we use the same monitoring 11 grid and we do this by installing those metal gauge 12 points, each gauge point has a receiver for the pins 13 from the mechanical strain gauge.
14 And what this lets us do is go to another 15 order of magnitude of accuracy. This lets us go to 16 a ten thousandth of an inch.
17 MEMBER CORRADINI: So let me stop you here 18 because early I think in when NextEra was doing the 19 initial or maybe the MPR folks were doing the initial 20 thing there was a comment made that the, I'll call it 21 the labor intensiveness is different between these two.
22 Can you tell me more about this? This one 23 strikes me as something I prefer to the sending a field 24 worker out to look at cracks. Is this just only 25 available in certain areas of, in terms of where you NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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117 1 can place the pins?
2 I'm trying to understand your choices 3 between these two because you made it a point of saying 4 that they kind of intermesh.
5 MR. SHERMAN: They intermesh. It's a 6 great lead in to where I was, they are very 7 complementary. The cracking index helps us get back 8 to the origin, to when we started, to before there was 9 any cracks, lets us know what's happened to date.
10 But there's a little bit, it's less 11 precise. Moving forward these provide more 12 information because now we have pins installed and it 13 lets us more precisely monitor expansion moving 14 forward.
15 And that's actually baked into the 16 structural analysis and into the structural monitoring 17 plan that we use CCI to start, lets us know where we 18 are. And then moving forward we combine it with the 19 enhanced accuracy of the expansion index.
20 MEMBER REMPE: So earlier I had asked well 21 how do you know where to put these pins in. And so 22 you would look at the prior slide and is it typically 23 where you see the bigger areas or more densely cracked 24 areas and you stick the pin in there or --
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118 1 forward one. You'll actually see in general, yes.
2 Remember I told you there's two tracks. You can see 3 here we have instrumented the worst appearing area.
4 MEMBER REMPE: I can't tell that is, but 5 if it is, okay.
6 MR. SHERMAN: So that would be --
7 MEMBER REMPE: I might put it a little more 8 to the right and up a little based on the picture.
9 MR. SHERMAN: Remember you may not be 10 seeing the entire grid. So it depends. There's two 11 tracks. One track where we do track the worst areas 12 and that's because that lets, you can always find the 13 worst.
14 And then in some of the analysis, as Glenn 15 was describing we use moderate. So once, in the second 16 track that's the calculations looks for representative 17 areas, not necessarily the worst case because that feeds 18 into the analysis.
19 So there's two tracks. It's not, there's 20 a lot to it.
21 MEMBER RICCARDELLA: But if you go back 22 to your previous slide, do I understand that you have 23 put your pins at the intersections of these grid points, 24 right? You put one in the middle --
25 MR. SHERMAN: Yes.
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119 1 MEMBER RICCARDELLA: -- because you want 2 to compare them to the CCI. So they can only put them 3 there and there or there and there.
4 MR. SHERMAN: Right. You can see on the 5 slide it's Level E, across the middle E, F, G, and H.
6 Those are the individual pins. So those are much 7 faster to do.
8 The expansion index with the mechanical 9 strain gauge is much more, is faster and more accurate.
10 MEMBER RICCARDELLA: Yes, but you're only 11 looking at the increment which is a much smaller thing 12 that you're trying to measure.
13 MR. SHERMAN: Correct, right. So they're 14 very complementary.
15 MEMBER BALLINGER: But there's a temporal 16 nature to this as well. I mean the fact that you put 17 a gauge on something that looks ugly, that could be 18 an area for which you're already on the plateau.
19 How do you know that, it's kind of a, I 20 won't use the right terminology, crapshoot in terms 21 of how do you know that there isn't an area that's about 22 to become an issue?
23 MEMBER RICCARDELLA: But as I understand 24 it once you get beyond that plateau you've got to go 25 to the through-thickness measurements. You don't keep NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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120 1 doing the in-plane measurements once you're on the 2 plateau, right?
3 MR. SHERMAN: Again, those are 4 complementary. And where would we, we would see 5 something and that's going to come into where Said talks 6 about how we group the areas.
7 So what would happen is if cracks started 8 developing in a new area the classification of that 9 area would change. So then we would probably go and 10 have to go look and add monitoring.
11 The monitoring points are not static. We 12 add them as driven by the structural analysis we add 13 locations to fuel, again it's that cyclic process where 14 the field data feeds into and supports the analysis 15 and the analysis drives the field data.
16 Right, sometimes they may need an 17 additional data point so we will go and add another 18 data point.
19 MEMBER BALLINGER: So ten years from now 20 or ten years from x, there may be an additional, there 21 will likely be additional places where you start doing 22 measurements?
23 MR. SHERMAN: Yes. And that's all baked 24 into the structural monitoring program at the plant.
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121 1 back up.
2 We also heard earlier about 3 through-thickness measurements. These are also used 4 to measure ongoing changes and to verify that the 5 structure remains within the bounds, within that 6 playground that's established by the large-scale 7 testing program.
8 Next slide. So deformation measurements.
9 We've talked, we've heard a little bit today about 10 deformation, right. All buildings are designed to 11 move.
12 If you walk out in this building you'll 13 see joints in the, expansion joints where the buildings 14 are expected to move.
15 MEMBER RICCARDELLA: You went too fast.
16 MR. SHERMAN: I'm sorry.
17 MEMBER RICCARDELLA: So in all the, the 18 previous slide, please. All the slides up to this point 19 were CCI which as I understand it is related to in-plane 20 expansion.
21 This is the only one where you're looking 22 at the through-thickness which is where you have to 23 get to once you get above that .1 or .2 percent 24 threshold, right. We talked earlier.
25 You said there are 26 buildings under NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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122 1 evaluation. I'm curious how many of those 26 have 2 forced you into the through-thickness measurement 3 versus still doing the CCI measurements?
4 MR. SHERMAN: If those are all the 5 buildings that Said will bring up later on that are 6 classified as Stage 3, Tier 3 sorry, I keep using the 7 wrong word.
8 MEMBER RICCARDELLA: So if you're going 9 to cover it later --
10 MR. SHERMAN: It's about 40 locations 11 where the through-thickness measurements are done.
12 MEMBER RICCARDELLA: Thank you.
13 MEMBER REMPE: So I know there's a license 14 condition for additional data to corroborate what 15 you've seen. But what about this thing about adding 16 additional locations.
17 Is that something that's covered by one 18 of the regulatory programs that again, it's our job 19 to ask these kinds of questions, but to make sure the 20 licensee continues to be vigilant in looking for new 21 locations and adding additional monitors?
22 MR. SHERMAN: Yes, yes. That process of 23 adding data is worked into the methodology document 24 and it also comes out as a result of individual 25 structural reports.
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123 1 So each structural evaluation has 2 requirements that roll out of that, that Said is going 3 to talk about that say how often you have to go back 4 and measure and where you have to do that.
5 MEMBER REMPE: Okay, thanks.
6 MEMBER RICCARDELLA: So continuing along 7 those lines. As I understand it your load factors, 8 your ASR load factors were based on measurements taken 9 so far and consider the scatter and, you know, the 10 standard deviation of those measurements.
11 It's possible that going forward in the 12 future that you might get some measurements that change 13 those distributions and result in a need to go back 14 and relook at your load factors.
15 MR. SHERMAN: Yes.
16 MEMBER RICCARDELLA: Is that, that's built 17 into the program?
18 MR. SHERMAN: Yes. Do you want to add 19 anything on that?
20 DR. BOLOURCHI: Up to now we have not seen 21 anything that changes by adding additional locations 22 that we have done. The distribution of data has not 23 changed.
24 And when we did those four zones we did 25 multiple distribution and anticipate this kind of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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124 1 affect that three different distribution that if you 2 get more data one of those will cover it and all of 3 those distribution the envelope goes to calculate the 4 zone factor.
5 Therefore, the possibility is there. But 6 probability is not going to change.
7 MR. BELL: Without getting into a lot of 8 detail we took a, when we did the curve fitting to the 9 data to determine the load factors we did some 10 conservative adjustments to those data in order to 11 account for the possibility of more numbers and where 12 things might go.
13 So I think the scenario you pose is possible 14 but highly improbable.
15 MEMBER BALLINGER: In an earlier part of 16 the presentation somebody mentioned that the degree 17 of volumetric expansion of the components are, consists 18 of near the surface wider cracks, but fewer and as you 19 go into the surface, subsurface smaller cracks but more 20 of them.
21 I think I recall somebody saying that.
22 Now has the, have the measurements that you've done 23 on the internal part, the through-thickness ones, have 24 they confirmed that contention?
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125 1 to the interior and see if by measuring the interior 2 you're actually adhering to that contention?
3 MR. SHERMAN: I haven't made the 4 correlation between the two. But I think you might 5 be, we expect the strain to be the same whether we have 6 a lot of little cracks and neither one of these methods 7 will really pick up or the through-thickness 8 measurement will not pick up how many.
9 It just measures total strain. So I can't 10 tell you if it's a lot of little ones or, you know, 11 one larger crack.
12 MEMBER BALLINGER: But what you're saying 13 is the strain is about the same?
14 MR. SHERMAN: I think that was what was 15 postulated earlier.
16 MEMBER BALLINGER: Postulated. Have 17 these measurements confirmed that?
18 MR. SHERMAN: I don't think we've done, 19 we have not done it.
20 MEMBER BALLINGER: Maybe I'm not using the 21 right terms. But that was a contention that the strain 22 was uniform.
23 MR. BELL: There is actually a lot of 24 literature that says that the strain reduces with depth 25 from surface. So the surface measurements should be NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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126 1 conservative.
2 Do you have anything to add to that, Dr.
3 Bayrak? You have to go up to a microphone if you're 4 going to add.
5 MEMBER BALLINGER: So I must have 6 misheard.
7 DR. BAYRAK: So the description that I 8 provided in the morning relates to a study we have done 9 at Ferguson Lab where we sectioned a beam to take a 10 look at what the surface crack patterns look like and 11 what the whole thing looks like through the thickness.
12 So the strains remaining reasonably 13 uniform within the test specimens was based on that 14 observation.
15 MEMBER BALLINGER: Okay, but what about 16 here?
17 DR. BAYRAK: So this particular 18 measurement is intended to measure how much the 19 thickness of a structural wall grows as opposed to how 20 the surface measurements which are in the x and y 21 directions vary as you move inwards into the structural 22 wall.
23 So this is a z, direction measurement and 24 the cracks that we see on the surface provide an 25 indication for x and y strains.
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127 1 MEMBER RICCARDELLA: Would the core 2 samples that you take out give you any information 3 regarding that?
4 MR. BELL: I'd like to make one clarifying 5 point on the statement that I just made. For in-plane 6 strain in a reinforced member, reinforced concrete 7 member generally the strain is reduced with depth 8 because the reinforcement restrains the strain as you 9 go deeper into it.
10 MR. SHERMAN: Right. We would not 11 actually expect a match between the through-thickness 12 because it's unrestrained and the in-plane surface 13 strain. Those would not be expected to track together 14 because of the effect of restraint.
15 MEMBER BALLINGER: So there would be a 16 significant difference between the cover, what do you 17 want to call it, the concrete area that has no rebar 18 in it, the cover area, a couple inches or so and once 19 you get into the reinforced area?
20 MR. SHERMAN: There is a difference. The 21 literature shows there is a difference. It's not giant 22 because the effect of the reinforcement is thrown to 23 a certain degree right.
24 And we're measuring in the same plane.
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128 1 it's different than the through-thickness. All right, 2 so we'll jump ahead to the deformation, starting on 3 deformation.
4 So to restart all buildings are really 5 designed to move, right. We do that intentionally.
6 We put gaps in buildings. We put thermal gaps in 7 buildings. We put seismic gaps in buildings.
8 So we do that to accommodate thermal 9 movement, earthquake and other such loadings, wind 10 movement. As such buildings incorporate specific, 11 back one, please.
12 We incorporate specific detailing to 13 accommodate that movement, right. So in the field we 14 measure those deformations or movement of those 15 different structural components at those points of 16 movement and at other locations to provide more 17 supporting information for the analysis.
18 So in addition to that normal seismic or 19 thermal movements the ASR at Seabrook provides another 20 source of deformations, right, as the affected concrete 21 expands. It's just a difference source of movement.
22 Before going into our deformation 23 movements I want to take a quick detour. We alluded 24 to it this morning. We're going to talk about plant 25 construction for a moment.
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129 1 Now if we jump to the next, right. So 2 Seabrook construction took place in excavated bedrock 3 which was near, the bedrock was very close to the ground 4 surface.
5 So after building the structures within 6 the excavated bedrock the remaining space at many 7 locations between the excavation face and the structure 8 was filled with unreinforced structural grade concrete, 9 right, of the same type used in the structures.
10 And they did it in two foot lifts. They 11 used that rather than a granular engineered fill.
12 Because this concrete is of the same type and 13 composition of the structural concrete that we've been 14 talking about so far there is evidence that it too is 15 undergoing ASR expansion, right.
16 This expansion creates pressures against 17 the backsides or underside of structures. You can see 18 how the structure is kind of worked into the bedrock 19 causing relative movements.
20 So we measured indicators of that movement 21 to be able to feed back into the structural analysis 22 that Dr. Bolourchi is going to talk about shortly.
23 Next slide, please.
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130 1 the analysis. For example, sometimes quantifying the 2 deformation pattern is critical to understanding the 3 performance and is required to support the analysis 4 as you'll hear about later on.
5 In a case such as this we'll measure the 6 deformed shape of the structure using a variety of 7 techniques. For example, when we were looking at a 8 vertical wall shown on the left we would mount, we put 9 a laser, a self-leveling laser beam on the floor and 10 measure the offset to the wall in prescribed steps as 11 we go up.
12 Similarly we'll do the same thing on 13 horizontal surfaces with the horizontally projecting 14 laser. And in all those cases we would bring them back, 15 those measurements back to a known reference location.
16 Next slide, please. So similarly, 17 sometimes we want to know information about the relative 18 position of buildings so that we can understand the 19 performance and to feed into the measurement analysis 20 and interpretation feedback cycle.
21 For example, we've heard a lot about fire 22 seal or the seals at seismic joints. That's what's 23 shown on the left here. That's a foam seal or a sealant 24 in a seismic joint.
25 So we measure and those are actually part NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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131 1 of the ongoing tracking program at the plant now. We're 2 measuring like 25 locations are routinely monitored 3 plus there's other measurements that are done in support 4 of building specific evaluations.
5 So we look at those joint sealant 6 movements. Other places, there was a question earlier 7 about the space between the containment building and 8 the containment enclosure building. That's what you 9 see on the right.
10 I've spent many an hour in that space.
11 So they're measuring the distance between the two.
12 And again, because of the large size of these things 13 some of those, what sounds like a large deflection could 14 actually be a very small strain because they're just 15 large structures overall.
16 So we measure those spaces in between there 17 with a laser range finder. And next slide.
18 MEMBER KIRCHNER: Just to make that last 19 picture palpable, how much movement are you measuring?
20 MR. SHERMAN: In between those?
21 MEMBER KIRCHNER: Yes, and the annulus, 22 fraction of an inch?
23 MR. SHERMAN: Since we've started 24 monitoring they're small. This is one of the locations 25 where they had, this was where one of the missile shields NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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132 1 was that had to be cut back where a gap had actually 2 closed.
3 So it had been an initial gap that had come 4 into direct contact. The trick is here, Said is going 5 to show a picture. Remember these are very large 6 structures that are very highly restrained.
7 So a very small amount of strain can 8 actually, gets kind of amplified by the shape of the 9 structure and where it goes by all the different 10 constraints on it. So we feed that right back into 11 the analysis.
12 That's why it's important to do these 13 measurements because it feeds into the analysis so we 14 can really understand what it is.
15 MEMBER RICCARDELLA: That missile shield 16 thing we're talking movements on the order of an inch, 17 inches, right?
18 MR. SHERMAN: Yes. Provided, again, we 19 don't know where it started. All we know is that it 20 was, it had come into contact, right. So we're assuming 21 that initial gap had been, was properly there which 22 is, I think, a valid assumption.
23 But again, very large structures, small 24 strains over large structures, yes. Without 25 necessarily a lot of stress associated with that. This NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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133 1 is a strain controlled phenomenon.
2 So you have to get into the strain world 3 in your head rather than stress world and that's hard 4 for a lot of people. Next slide, please. So we will 5 also occasionally undertake specialty testing in the 6 form of petrographic examinations when it's needed to 7 provide specialized information as was described 8 earlier in the large-scale testing program.
9 This is done only in special cases where 10 we find a difference between the measurements, 11 observations and analysis. For example, this could 12 be a case where an indicated strain by the cracking 13 index really doesn't match with the appearance or the 14 pattern cracking and it doesn't match with what we see 15 in the results of the analysis.
16 There's a disconnect in our data. And we, 17 we're curious if that cracking is actually due to ASR.
18 So in that case we'll use petrography to see if the 19 source of that cracking is ASR or if another cause is 20 likely.
21 Next slide, please. So an example of the 22 process in this case, this is where the cracking index 23 suggests that actually a high degree of ASR. But that 24 was inconsistent with the overall pattern with what 25 we saw on the surface.
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134 1 You know, we didn't see any of that ASR 2 gel. And it was inconsistent with the results of the 3 analysis. If we really had that much strain the 4 analysis showed us that other things should be happening 5 that weren't.
6 So we went back and this is actually in 7 the pre-action valve structure. So we went in and 8 removed a core to test that assumption that all the 9 cracking was caused by ASR.
10 So we took a core centered at a surface 11 crack. Next slide, please. Then we take that core 12 out, cut it, polish it and perform a petrographic 13 examination on the core.
14 Petrographer is really a geologist who 15 studies concrete. They're specialist geologists who, 16 because concrete is just an artificial rock. So we 17 do that with two petrographers on site still under a 18 full QA program.
19 We set up a temporary lab on site to do 20 that. And in this case we did the petrography and found 21 that the near surface cracking that was visible was 22 actually not due to ASR.
23 It's pretty clear the overall picture is 24 on the left. But on the right, it's hard in this room 25 to see, but it does not exhibit any of the typical NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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135 1 characteristics of ASR and the petrographers confirmed 2 there is no ASR in this core.
3 We don't see ASR gel formed. Usually you 4 would see it filling air voids and other cracks within 5 the concrete. We don't see that. The cracks do not 6 start in the aggregate and extend outward. They 7 actually run around the outside edge of the aggregates.
8 The aggregates themselves don't show signs 9 of reaction. We don't see any alteration rings. So 10 in this case we are able to find that the cracking was 11 not due to ASR. It was attributed to other locations.
12 So we don't have to account for it as an 13 ASR load. But we do track down where it came from.
14 All right, so next slide. So, I guess, in conclusion, 15 you know, we've gone through how we get the field data 16 and how it's used in support of the methodology 17 document, right.
18 It provides input data, a feedback loop 19 into the whole analysis cycle and information to support 20 that correlation of the work during the whole evaluation 21 cycle. And as another side, another track that it does 22 is the field data provides a means and is the basis 23 for a lot of the ongoing structural monitoring program 24 that goes on at the plant right.
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136 1 baked into the ongoing structural monitoring plan that 2 you'll hear about later on. All right. So with that 3 I think we turn it back to Said.
4 DR. BOLOURCHI: Okay, thank you. The goal 5 in here is to describe the structural evaluation 6 methodology to define a procedure which is repeatable 7 and can be applied to all Category 1 structures.
8 And also there is another terminology we're 9 going to start using establishing a threshold limit 10 for potential future growth of ASR in each building.
11 And I will describe what does this threshold mean.
12 Is it building specific? And it is a 13 measure that we can expand the ASR still staying within 14 the limit of the defined code. Next slide.
15 All of you are well aware of where we are.
16 First, we started with the UFSAR and we have defined 17 an LAR. As part of the LAR we have attached to that 18 the load and load factor as a document and that's an 19 attachment to the LAR.
20 The material properties are per spec 21 defined in the original design per the larger-scale 22 testing that was discussed in the morning. Also LAR 23 defined a creative approach and I will describe that 24 creative approach a little bit further on to that it 25 quite a bit of effort to evaluate all these structures NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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137 1 in a timely manner.
2 Therefore, we tried to do it on graded 3 approach. And also we defined code supplement that 4 we will, the document five supplement to the code for 5 evaluation of this structure.
6 And we go through those specifically.
7 Then you come, the issue with the LAR is high level 8 and is not a repeatable, although it defined the process 9 but it is not detailed enough that can be defined, can 10 be repeated by sort of any other structural engineer.
11 Therefore, now we have defined a 12 methodology document and it is very detailed and is, 13 has three big segments. One is the analysis approach.
14 In that it will be, the requirement is to be a 15 repeatable process that can be applied for all Category 16 1 structures.
17 And also it defined a graded approach for 18 field data. Therefore, for different graded analysis 19 we will get conservative or more data as is needed.
20 And then the threshold limit is using the design margin 21 for the structure at the -- right now to extend how 22 much more it has, that is still within the code limit.
23 And that goes through the monitoring as 24 to, as it gets approached to that there will be proper 25 action to take place. And the next one is the finally, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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138 1 structural evaluation.
2 And structural evaluation is the same 3 equation that you see from the first one. And 4 structural capacity defined by the code for all the, 5 any of the graded approach includes the reliability 6 inherent in the code.
7 The structural capacity should be greater 8 than all the load included in their structure, the ASR 9 load. When the structure is evaluated based on that 10 then we'll define the parameters that need to be tested 11 and the frequency of the testing and the requirement 12 of the trending.
13 And that will be defined in each of the 14 calculation packages. If you get any of the 15 calculation, Chapter 8 defined those things very 16 detailed on that, that can be taken directly from there 17 and put into the structural monitoring program which 18 has been in place.
19 And the last box is the structural 20 monitoring program that it is maintained completely 21 by the Seabrook plant. Next slide. Just to, since 22 the threshold is a new terminology that we are 23 introducing we try to use a similar equation that Glenn 24 discussed earlier.
25 On the left hand side it is the resistance NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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139 1 which we haven't changed. On the right hand side I 2 divided it in two terms. One, all the load effect that 3 is already in the UFSAR.
4 Therefore, we are not changing those. We 5 are not changing the load factors. All of them is 6 there, therefore, that is the sum of the factor designed 7 basis load that is there.
8 Then we have a factor of I, which is the 9 load factor for ASR. And then SA which is the load 10 factor load for the ASR. Then the last item which put 11 in green, KT edge, what we call the threshold factor.
12 Therefore, we go to the field and we measure 13 the ASR and the load by the strain, for example. We 14 put that thing as SA. We multiply it by a factor which 15 is always greater than one.
16 And it can be very high. In the end I'll 17 give you some summary on that. Therefore, we always 18 grade down one. One is the right at this present time.
19 If it is 1.5 it is 50 percent more than 20 whatever it is now. That is the only associated with 21 the ASR load because the other load is constant, is 22 not changing. Go ahead.
23 On the field data already we had a long 24 discussion. We always start with the walk down for 25 the observation. And we also define in detail in the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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140 1 methodology document a graded approach for the field 2 data collection.
3 The reason that they will see the graded 4 approach if a building has significant margin already 5 in it we try to do much simpler calculation. Keep a 6 lot of the conservatism.
7 As it is resolved we don't need as much 8 data. We can use more conservative calculations, a 9 lot more conservative for the, that and evaluate the 10 building. And also the typical data is all listed in 11 the methodology.
12 Therefore, this methodology is designed 13 such that the infrastructure need to reevaluated can 14 be done without any license change requirement. It 15 is all included in that.
16 Therefore, the in-plane strain we talked 17 about CI, CCI and pin-to-pin or expansion measurement.
18 And also changing in seismic gap, structural 19 deformation and structural distress like crack and 20 crack rate.
21 All of that has been accurately listed in 22 that on how it can be used. And also in, there is a 23 good section in the methodology that defines how do 24 you adjust what we measured in the field.
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141 1 is ASR and what is not ASR? Therefore, you can go and 2 there are five different requirements to be ASR.
3 Therefore, that is defined.
4 But also there are other cracks that we 5 know that they are not ASR like pressurization. We 6 have data from 1980 that containing -- we have the 7 pictures and the grade of where the crack was under.
8 The temperature affect differential ASR 9 between these structures have produced a structural 10 crack not an ASR crack and other sorts of structural 11 deformation. And if needed we'll do petrography to 12 identify if it is or is not because usually when we 13 go to a place then we can look at that.
14 And if it doesn't jive that all the, why 15 should it be ASR and we cannot completely identify it 16 based on the structural primarily on this lab on plate 17 -- lots of times we do petrography to confirm if it 18 is not ASR.
19 CHAIRMAN SKILLMAN: Dr. Bolourchi, would 20 it be acceptable if we took a 15 minute bio break because 21 the next portion of the presentation will be the graded 22 approach. This might be a clean break, give everybody 23 a few minutes to stretch their legs. Would that be 24 all right?
25 DR. BOLOURCHI: Absolutely.
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142 1 CHAIRMAN SKILLMAN: Ladies and gentlemen, 2 we are in recess for 15 minutes. Please come back at 3 quarter past three by that clock.
4 (Whereupon, the above-entitled matter went off the record at 2:57 p.m. and 5 resumed at 3:14 p.m.)
6 CHAIRMAN SKILLMAN: Ladies and gentlemen, 7 we are back in session, let's begin. To the presenters, 8 we're late in the day, we're behind schedule, I ask 9 you to take every action that you can to speed up this 10 presentation.
11 DR. BOLOURCHI: Okay.
12 CHAIRMAN SKILLMAN: We need time for the 13 staff, we need time for the public. We will go as late 14 as we need to go, but let's proceed forthwith. Thank 15 you.
16 DR. BOLOURCHI: Thank you. The talk about 17 the graded approach, next two slide, we go a little 18 bit slower, but after that, we'll try to go as fast 19 as we can.
20 In each of the building we start, we start 21 with the review in the field data and all the document 22 that there are, the original design document, review 23 all the Structures Monitoring Program to date, to figure 24 out if there was any observation over the life of the 25 plant.
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143 1 And then, we do initial walkdown. And at 2 that point, we'll decide which space under how much 3 margin it is in the original design and what is the 4 status of the ASR and so on.
5 CHAIRMAN SKILLMAN: For those of you who 6 are on the phone line, please put your phones on mute.
7 Thank you.
8 DR. BOLOURCHI: Okay. Then, we will start, 9 we can start at any of the three stages of analysis.
10 Within all three stages, the commonality is that all 11 will be evaluated based on the code of record.
12 Therefore, in any of these three condition, 13 the conservatism inherent in the code will remain intact 14 for all of these stages and type of analysis.
15 MEMBER MARCH-LEUBA: So, I can understand, 16 you call it the stages. Is that you're doing all three 17 for each component? Or are these options?
18 DR. BOLOURCHI: These are options and you 19 can start at any of them.
20 MEMBER MARCH-LEUBA: So, it's an option and 21 you can choose one of the three for a component and 22 stay with it forever?
23 DR. BOLOURCHI: We can start with Stage One 24 and if you need to reevaluate it, I have a choice of 25 going to Stage Two.
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144 1 MEMBER MARCH-LEUBA: You do a Stage One, 2 if you don't meet the criteria, you go to Two, if you 3 don't meet the criteria, you go to Three?
4 DR. BOLOURCHI: But if a structure is 5 already in a more critical or as defined, we can start 6 at Stage Two. You don't need to go One, Two, Three, 7 we can go One, Three, if needed.
8 So, the Stage One is, obviously, the most 9 conservative calculation. These are usually we use 10 all the original design calculation, we don't do any 11 more recalculation of the demand.
12 Usually, the original design is done at 13 a part, the design stage very conservatively. And we 14 calculate the ASR in conservative way.
15 The way we do that, we go to the worse area 16 of the building and we measure that one. We amplify 17 that for the entire area. We expand that, if it can 18 take that load, obviously it can take even if you have 19 more data in that.
20 We start with the most conservative way 21 of calculation, which is really over-conservative, but 22 saves lots of time and has lots of margin in that.
23 Since it has lots of margin in this calculation, we 24 will mandate every 36 months going back and make sure 25 that nothing is changed in that.
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145 1 The Stage Two is still very conservative, 2 because we still use all the original design 3 calculation.
4 All the loads which were calculated with 5 the original design, we don't touch it, we just go back 6 to usually in the old calculation, all that has been 7 done based on the closed form solution, very 8 conservative. They will pick up those very directly.
9 But usually, then, we will model the ASR 10 using finite element. And generally, that is the case 11 when the differential in the one area versus the other, 12 that difference between that, if you cannot simulate 13 by hand calculation, become more complex.
14 Or if the geometry is complex. If you have 15 a cylinder and a rectangle next to each other, trying 16 to estimate it by hand become very difficult.
17 In that case, we go to calculating the ASR 18 demand by the finite element, then we add to original 19 calculation and then, we will monitor it every 18 months 20 after it pass.
21 The Stage Three, which as I said, retain 22 all the evaluation based on the code, is the more 23 defined. We calculate -- we develop a finite element.
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146 1 the sustained load at this point. And I have a figure 2 for that.
3 And then, we calculate all the loads, the 4 dead load, live load, lateral soil pressure, all the 5 load that we need in the original design and the ASR, 6 using that finite element. And then, we will monitor 7 these structure every six months.
8 If you go to next slide, this is a flowchart 9 for a Stage Three analysis, which is the most refined 10 one. The other one become simpler than that. We 11 started with Stage Three, either because we started 12 at that or it can come from the previous analysis.
13 Then, we will develop the finite element 14 and we correlate that to the field data that we will 15 talk, and I have a figure to represent that. And then, 16 we use, when the finite element model is validated, 17 then we will use it to calculate all the load, ASR and 18 non-ASR.
19 And then, we will amplify ASR load with 20 additional load, more with the threshold factor for 21 future growth of ASR. We calculate total load and then, 22 we come to the box at the junction.
23 The question is, is the capacity still 24 greater than the demand? Capacity, the core capacity 25 still. And the demand is all the load calculated.
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147 1 If it greater than that, therefore, it meet 2 the licensing basis, as appended by LAR, which obviously 3 including ASR load, we define threshold limit and the 4 reference value for monitoring every six month.
5 If it doesn't pass, we have two choices.
6 Either we can go back and reevaluate with the same 7 methodology, how can we do it? Because if we can go 8 back and get more field data, we'll observe more 9 variation in the structure.
10 Or we can do petrography, if you have 11 assumed something is ASR and if it didn't qualify, we 12 can go back and do petrography and confirm it is not 13 ASR. If it is not, then we can go back and reevaluate 14 this structure.
15 And that can happen if you approach the 16 threshold. Right now, we don't have that condition, 17 but it is anticipated in the methodology to be able 18 to do within that.
19 Or the other option, we can go and retrofit.
20 And we have already defined some retrofit and some 21 has been completed, that will be discussed by Seabrook.
22 Next slide, okay.
23 The model evaluation, model correlation, 24 corroboration with the field data is important step.
25 On the left-hand side is the input that will go to NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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148 1 the finite element. It is the CCI on the top left.
2 And as a Stage Three, the dot represent 3 the number of points that we have taken. As you see, 4 there is many points on that. Then, below that is the 5 pressure from the concrete backfill. And then, all 6 the other load.
7 On the right-hand side, we will get -- we 8 have measure those, the deformation, either through 9 the seal or through the annulus measurement. And then, 10 we have amplified the deformation in order to be visual, 11 otherwise you don't see any deformation. And then, 12 we will try to match the deformation to that.
13 The only variable in here is the concrete 14 backfill, we can adjust, that we'll discuss, to match 15 that. Or in the other structure, it can be cracking 16 or cracking pattern or strain. And that is the output 17 and that the input.
18 One the comment that was in the morning 19 about the ASR, the CI value of the containment enclosure 20 to be small. We have the trending analysis with the 21 pin-to-pin measurement and we have looked at the slope 22 of that versus the slope of the CI measurement, starting 23 from the early eighties to that value.
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149 1 the evaluation of the CI. I mean, for the containment 2 enclosure building. Next slide.
3 MEMBER RICCARDELLA: You don't have a plot 4 here that shows it, but it's saturated, you're saying?
5 It seems to have reached the level of threshold?
6 DR. BOLOURCHI: Well, your question, I 7 understood that you were saying that that is in the 8 low level and there may be a difference between the 9 measurement with the strain measurement versus the CI 10 measurement.
11 And I'm saying that we have, like, eight 12 years of pin-to-pin, which is physical measurement that 13 describe on that, that it account for all the strain.
14 And when we get the slope of that and we 15 go back to the -- go directly down, compare to the slope 16 if you started the CI all the way to the early eighties, 17 these two slopes are very similar to each other.
18 Therefore, that CI measurement that we use 19 for the containment enclosure building is 20 representative of the actual value. We have two ways 21 of confirming that value. Okay, next slide. Some of 22 the attribute of the --
23 MEMBER RICCARDELLA: Can you go back a 24 moment?
25 DR. BOLOURCHI: Sure.
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150 1 MEMBER RICCARDELLA: So, the upper 2 right-hand corner, on a bigger version, I was trying 3 to understand you, this is, you're comparing your finite 4 element measure deformations to the actual measured 5 deformations. I had trouble kind of interpreting which 6 --
7 DR. BOLOURCHI: Oh, okay. The dark black 8 line is the -- which is circular, that's the original 9 shape.
10 MEMBER RICCARDELLA: Okay.
11 DR. BOLOURCHI: Then, we put two circle, 12 inner and outer, each of them representing one inch 13 of deformation.
14 MEMBER RICCARDELLA: Yes.
15 DR. BOLOURCHI: Obviously, at 180, 160 feet 16 diameters, one inch, you will not see, but for 17 visualization.
18 Then, the dots are the actual measurements 19 that you see on the dots. And the lighter blue color 20 is the deformation presented by the finite element.
21 This at one section, we have done it at multiple 22 sections, to make sure that the deformation matches 23 the data on that. Okay?
24 MEMBER RICCARDELLA: Okay.
25 DR. BOLOURCHI: On the attribute, we are NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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151 1 using general purpose program ANSYS, which we got 2 license under the full QA and we have audited that and 3 we brought it under our QA program.
4 And that program has been used for multiple 5 other plans that we have used and others have used for 6 the industry. And the internal ASR is the ASR of the 7 reinforced concrete structures.
8 And for each of the finite element that 9 I showed at the previous slide, each of the element 10 consist of three elements. One representing concrete 11 and two representing rebar in one direction and two 12 orthogonal direction.
13 We expand the concrete by the CI 14 measurement and then, the reinforcement model will pull 15 it back and produce the pre-stressing that was observed 16 in the testing program. Therefore, in here, we will 17 see the pre-stressing that require to model on that.
18 And the concrete backfill is, obviously, 19 from the measurement that we have a bigger section, 20 all of which we defined.
21 MEMBER KIRCHNER: So, may I ask, do you test 22 your -- I'm looking at the sub-bullet there, on -- I'm 23 interested how the nodalization might impact the 24 results. So, I assume you benchmark the code, with 25 the assumptions you just described, against the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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152 1 large-scale test program beams?
2 Or how did you determine that the 3 nodalization used in the finite element method applied 4 here was actually doing physically what happens in the 5 structural member?
6 DR. BOLOURCHI: We have some hand 7 calculation that we can simulate that very easily.
8 And we have also used different method of calculation 9 and compared to that.
10 And the result -- we also simulated some 11 of the testing that was done in response to some of 12 the question that was raised by NRC. We showed that 13 all of them are simulated properly.
14 MEMBER KIRCHNER: Like this morning, we saw 15 a large beam being flexed quite a bit. Were you able 16 to model that --
17 DR. BOLOURCHI: We did not --
18 MEMBER KIRCHNER: -- behavior and failure?
19 DR. BOLOURCHI: We did not simulate that 20 particular one, but we have done the north wall of 21 Seabrook, for example, which has about one inches of 22 deformation.
23 We have the CEB, which has plus or minus 24 two inch of deformation. And we have simulated those 25 and we match the actual field measure.
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153 1 MEMBER KIRCHNER: Yes, but I can adjust a 2 code to get to the field measurements. What I'm 3 thinking more is kind of a blind calculation of the 4 large-scale test program results, to have confidence 5 in the code as applied and that the nodalization is 6 sufficient to capture the effects, because the 7 properties are changing in the concrete mix and not 8 in the steel, other than, obviously, there's stresses 9 induced.
10 So, I'm just curious if you did some just 11 basic checks of the methodology, using the FEM code 12 against those test specimens from the large-scale test 13 program.
14 DR. BOLOURCHI: We have not done a 15 validation against the test program. In our QA 16 program, we have done enough to confirm that it is done, 17 but we have not -- if specifically you are saying that, 18 did we validate our program against large-scale test, 19 we have not done that.
20 MEMBER RICCARDELLA: I thought you said you 21 did one.
22 DR. BOLOURCHI: Pardon me?
23 MEMBER RICCARDELLA: I thought you said you 24 did simulate one.
25 DR. BOLOURCHI: We have simulated some of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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154 1 the values on that --
2 MEMBER RICCARDELLA: On the large-scale --
3 DR. BOLOURCHI: -- and we have captured the 4 same delay cracking that was observed. We have 5 simulated that in the analysis. But we did not get 6 exact same dimensions.
7 MEMBER RICCARDELLA: If your ANSYS 8 analysis, it's a linear analysis?
9 DR. BOLOURCHI: ANSYS is for the -- what 10 we have use is a linear analysis.
11 MEMBER RICCARDELLA: Linear, so if you were 12 simulating a test, you could only go up to the point 13 of first cracking?
14 DR. BOLOURCHI: That's all it is. I mean, 15 we have extended it for ourselves to see with going 16 there.
17 But in our evaluation and modeling, we have 18 limited to the linear analysis, as required by the --
19 we did not extend to any nonlinear vein. We are not 20 getting to that range of large reflection that it was 21 tested. Okay.
22 The other factors, the structure cracking 23 and the cracking is associated -- we have tied the 24 cracking to the strain in the concrete. Therefore, 25 any of the pre-stressing has to be overcome. That NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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155 1 simulated delay cracking that was observed in the field.
2 Next slide.
3 This slide, we have seen before.
4 Basically, growth of concrete backfill can put load 5 on the structure. Let's go to the next slide.
6 In here, in the Methodology Document, we 7 have quite a bit of extension of discussion and that 8 here are coded basic concept of it. At any depth on 9 the concrete backfill, as it try to grow, will produce 10 a load, we assume a load equal to the overburden, is 11 all the load that is sitting up there.
12 And since if it want to grow beyond that, 13 it will grow vertically, doesn't need to grow 14 horizontally, is the direction of least resistance.
15 But when we want to simulate the deformation, we can 16 reduce that, like we have simulated in the CEB, we can 17 reduce that in order to match the deformation.
18 Or if we are not observe a crack on the 19 wall, we can assume that the pressure equal to the crack, 20 which is the conservative value. Therefore, when we 21 come to field observation, we say, go and make sure 22 there is no crack observed in the field. That's how 23 we adjust on that. Next slide.
24 The supplement on the code, there are five 25 supplement. The first one is, we add ASR load base NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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156 1 on the load and load factor, which were discussed, to 2 all the FSAR load. We are not changing FSAR load, we 3 keep all the load, we add the ASR to that.
4 And the second one is that we are accepting 5 the code calculated values as capacity for the 6 structure. And that is based on the large-scale 7 testing.
8 The third one is, ASR produces compression 9 in the member and there is a terminology called shear 10 friction, that it is sliding of the concrete over each 11 other.
12 If you have compression, you have to 13 overcome the sliding friction. ACI 318-71 does not 14 address that. All the other code beyond that, 15 including 83 version and ACI 349, address that 16 consistently. Therefore, we are using 318-83, entire 17 section of that, instead of the original 71.
18 And the next two is reduction of the 19 structural property, because of the cracking. The 20 number four is full flexure, which ASME 443 and current 21 ACI all recommend that, in lieu of doing a tedious 22 calculation, you can use a 50 percent reduction and 23 that's a conservative.
24 Because we want to get a higher value, this 25 is a displacement control, more stiff you put, more NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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157 1 load you going to get.
2 And the last one is axial and shear 3 reduction, because of the cracking. Again, the code 4 71 says, you can reduce it to zero. We gradually reduce 5 it in order to capture more load and that is standard 6 in the industry. Next slide.
7 The threshold parameters, this is specific 8 for each structure, for structure monitoring, after 9 we evaluate the building. But these parameters is from 10 a set of the well-defined in the methodology.
11 Therefore, we are not coming up with a new 12 case, because if it come later they want to reevaluate 13 any of these building, the methodology already defined 14 what are the parameters that you can do.
15 And those are in-plane expansion. As you 16 see, I'm not talking about CI anymore, it's just the 17 expansion. And the preferred method is the pin-to-pin 18 expansion here. We also, we can look at the 19 deformation, seismic joint, or structure deformation 20 as included. Next slide.
21 In the summary, we have provided a 22 Methodology Document that includes how to include ASR 23 load and load factor to maintain inherent reliability 24 in the code.
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158 1 for analysis and collecting data, and also, threshold 2 values and limit that need to be monitored in future.
3 Therefore, as taken, is that the repeatable analysis 4 process is for evaluation of all Category I structures 5 has been defined in here.
6 Next, we go to the next box in the 7 evaluation of the structure. Therefore, now, we use 8 the Methodology Document and apply to each of the 9 Category I structures.
10 And in here, we going to define established 11 limit for the threshold and how much more these 12 structures have capacity to go. And again, the same 13 thing is, we are giving back to that the structure 14 capacity based on the code, it should be greater than 15 all the loads on that.
16 We go to next slide. For all Category I 17 structures that are being evaluated for the site, we 18 confirm that the structure meet the code of record and 19 we will determine the threshold for future ASR growth 20 and will define for each of them how often they need 21 to be monitored, based on the stage of the analysis 22 was done.
23 And we also defined the parameters that 24 need to be monitored. Also, we will identify if there 25 is an area of the structure that require enhanced NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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159 1 monitoring, which can be as short as two months 2 interval. And also, if there are some retrofit 3 required for the structure.
4 And a summary of the structure evaluation 5 is summarized in this table below. Obviously, it 6 doesn't add up to 26, I --
7 MEMBER RICCARDELLA: That was my question.
8 DR. BOLOURCHI: -- can tell you right away.
9 Because what we have done is the number of structure 10 evaluation packages.
11 Some of the structures, we can combine them 12 together and evaluate it together. Some structures, 13 we had to do three or four different evaluations.
14 Like the example is manholes, there are 15 16 different manholes, different geometries, trying 16 to put everything in one -- and some of them are Stage 17 One, some of them are Stage Two -- become very difficult, 18 trying to stay with the structure.
19 Therefore, 19 of them is completed and the 20 threshold is from 1.2 to 3.7 for the ones which is 21 completed.
22 And out of the eight which is left, four 23 of them, one of them is Stage One, one of them is Stage 24 Two, two of them is Stage Three. We have the draft 25 calculation, but it is going through internal review NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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160 1 before we send it to Seabrook for evaluation.
2 MEMBER MARCH-LEUBA: You might not know the 3 answer to this, order of magnitude, the equation that 4 controls this is capacity greater than the sum of the 5 loads, the load for the ASR, what's the percentage of 6 the total load?
7 DR. BOLOURCHI: It's very good question.
8 MEMBER MARCH-LEUBA: And I know it depends 9 on -- each one is different, right?
10 DR. BOLOURCHI: Yes, each one is different, 11 but there are places that ASR can be small, five-ten 12 percent. There are places that the ASR can be 40 13 percent of the load.
14 MEMBER MARCH-LEUBA: You've seen 40 percent 15 increase?
16 DR. BOLOURCHI: I have seen 40 percent and 17 there can be some structures that, in some direction, 18 there was not -- doesn't produce load, but ASR become 19 primary load on that.
20 MEMBER MARCH-LEUBA: But as a percentage 21 of the capacity, not a percentage of the total sum?
22 DR. BOLOURCHI: Oh, it could --
23 MEMBER MARCH-LEUBA: Because, I mean, if 24 you didn't have any load, then any load is a significant 25 change.
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161 1 DR. BOLOURCHI: Right. I mean, as a 2 percentage, yes, because we always add up everything 3 to see how much is compared to the load that was design.
4 As a total load, probably about, could be about 30 5 to 40 percent. I mean, this is just an estimate. I 6 mean --
7 MEMBER MARCH-LEUBA: Relevant, it was not 8 a wasted exercise, we --
9 DR. BOLOURCHI: Yes, it is not -- I mean, 10 I cannot say it one or two percent, it a value greater 11 than that.
12 MEMBER REMPE: I'd like to understand 13 uncertainty and try and get a feel for it. Could you 14 go back to Slide 49, please?
15 DR. BOLOURCHI: Okay.
16 MEMBER REMPE: On the lower right, sometimes 17 the data are very -- I assume the data are the little 18 dots or --
19 DR. BOLOURCHI: That's correct.
20 MEMBER REMPE: -- diamonds and --
21 DR. BOLOURCHI: That's correct.
22 MEMBER REMPE: -- the predictions are the 23 line that are reddish --
24 DR. BOLOURCHI: Correct.
25 MEMBER REMPE: -- colored. Some places are NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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162 1 matching quite well, but then, if we look at towards 2 the end there, it looks like that it's almost 0.009 3 versus -- it looks like the data could be off by a factor 4 of two?
5 DR. BOLOURCHI: Well, okay, that's great 6 question. And if you look at that, in the actual --
7 on the right-hand side, if you look at the right-hand 8 side on the top, we have different colors.
9 MEMBER REMPE: Right.
10 DR. BOLOURCHI: And that area that you are 11 referring to is the right-hand side of that, which is 12 a special area, which is the average of the -- we have 13 actually input the average value between these two 14 locations. And that is the vertical direction that 15 was applied.
16 And the reason, because that value was very 17 high, either we can go and do a petrography and confirm 18 it's not there, but we will -- at this stage, we say, 19 okay, let's have that, but we have, in that area, we 20 measured about eight or nine values and we put the 21 average of that eight or nine values into the model, 22 as a not constant value.
23 But when it comes with all the other load 24 combinations and the deformation, then the strain 25 deformation, it doesn't become constant, it become a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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163 1 gradual value.
2 MEMBER REMPE: Okay.
3 DR. BOLOURCHI: But it is, as an input, it 4 is --
5 MEMBER REMPE: Okay. So --
6 DR. BOLOURCHI: -- average.
7 MEMBER REMPE: -- my takeaway, since I'm 8 not an expert in this, is if you see something like 9 that, you investigate it and try and understand and 10 get a better feel for what's going on --
11 DR. BOLOURCHI: Absolutely.
12 MEMBER REMPE: -- at those locations?
13 DR. BOLOURCHI: Absolutely. And that is 14 exactly -- that was very important for us to do. For 15 that particular one, I know I spent at least about three 16 months.
17 MEMBER REMPE: I don't want to know what 18 you did for three months on it, but thank you.
19 MEMBER RICCARDELLA: Now, is that within 20 the scatter that we talked about from the mean to the 21 -- you talked about how you built the spread in the 22 data into the load factors for ASR.
23 Now, this one here, does that say that three 24 standard deviations is a factor of two or something 25 like that? Is that what that tells you?
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164 1 MR. BELL: This is somewhat of an anomaly.
2 We're looking at the differences between an analysis 3 and a measured value.
4 MEMBER RICCARDELLA: Yes.
5 MR. BELL: And we often will input a measured 6 strain, under the presumption that it's all ASR. And 7 what Said is saying is, if the model tells us there's 8 a large discrepancy there, then we need to chase down 9 why there's a discrepancy.
10 So, we'll either refine the analysis or 11 do petrographic analysis to explain the difference, 12 we just don't let it lie.
13 So, this isn't so much variation in field 14 data as the model not, at first blush, completely 15 describing the structural behavior. And then, we chase 16 that down.
17 MR. SCHULTZ: Said, your last slide on 18 evaluation packages shows that there are three that 19 are in Analysis Stage, excuse me, nine that are in 20 Analysis Stage Three. And so, they're being monitored 21 on a six-month frequency?
22 DR. BOLOURCHI: Yes, after -- they are on 23 a six months, after it is completed. The one that --
24 MR. SCHULTZ: Yes.
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165 1 will go on a six months monitoring.
2 MR. SCHULTZ: How long does it take to do 3 these analyses?
4 DR. BOLOURCHI: Is about --
5 MR. SCHULTZ: Roughly?
6 DR. BOLOURCHI: -- five-six months, at 7 least.
8 MR. SCHULTZ: Are any in the augmented, you 9 mentioned augmented, could be less than six months, 10 are any of the completed package less than six months?
11 DR. BOLOURCHI: Actually, in the 12 Methodology Document, we have provisions, if there is 13 an area that may require retrofit, then we will put 14 it on a higher monitoring --
15 MR. SCHULTZ: But you don't have that for 16 these --
17 DR. BOLOURCHI: -- until we --
18 MR. SCHULTZ: -- completed packages?
19 DR. BOLOURCHI: -- it is retrofitted and 20 the issue goes away.
21 MR. SCHULTZ: I see where that fits, thank 22 you.
23 MEMBER MARCH-LEUBA: But the monitoring, 24 what you do is, you check the cracks again every six 25 months, to make sure that they're below a threshold?
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166 1 You don't rerun the analysis?
2 DR. BOLOURCHI: That's correct. That's 3 correct.
4 MEMBER MARCH-LEUBA: So, and we were told 5 a single location takes about a couple of hours to 6 perform?
7 DR. BOLOURCHI: That's correct. And when 8 we get to the monitoring, there's a -- our preferred 9 method is the expansion measurement, which most 10 difficult time is to get to the location. The actual 11 measurement is very fast, usually --
12 MEMBER MARCH-LEUBA: I have not read that 13 slide yet, but suppose you give the threshold in units 14 of CCI change instead of 1.2, that doesn't mean much 15 to the guy in the field.
16 DR. BOLOURCHI: Oh, yes. No, no, no, we 17 will define exactly for one --
18 MEMBER MARCH-LEUBA: The maximum CCI is 4.7?
19 DR. BOLOURCHI: Right. We will define as 20 one value or at one location or aggregate, depending 21 on the deformation pattern, aggregate of that, and will 22 give them the actual value.
23 And also, if it is Stage One, we reduce 24 that by 90 percent, and if it is a Stage Two, we reduce 25 it by 95, and so on.
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167 1 MEMBER MARCH-LEUBA: I'm just thinking, 2 human factors, everybody in that table understands what 3 a load effect S sub A means. The tech you're going 4 to send in the field doesn't know what that is.
5 DR. BOLOURCHI: No, that --
6 MEMBER MARCH-LEUBA: They don't know what 7 CCI is.
8 DR. BOLOURCHI: That's correct. We give 9 the actual value of, this much strain cannot go more 10 than this value. We give the exact value in the table.
11 MEMBER RICCARDELLA: So, when you say the 12 threshold factor range from 1.2 to 3.7, can I assume 13 that the 1.2 is associated mainly with the ones in Stage 14 Three and the 3.7 would be way down in the Stage One?
15 Is that --
16 DR. BOLOURCHI: That's usually -- there's 17 one or two building which has 1.2 and is Stage Three.
18 The other one, we have 1.4, 1.7, 2, 2.5, and it can 19 be -- there is one building that is 1.3 and by design, 20 we set it on that.
21 That it is a Stage One, because doing any 22 higher evaluation doesn't change. But as a part of 23 the methodology, we --
24 MEMBER RICCARDELLA: But 1.2 means --
25 DR. BOLOURCHI: -- put that value --
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168 1 MEMBER RICCARDELLA: -- you're 80 percent 2 of the way there, if you can only take 20 percent more 3 expansion before you hit the limit?
4 DR. BOLOURCHI: Before you hit the limit 5 and --
6 MEMBER RICCARDELLA: Have you to do so?
7 DR. BOLOURCHI: -- you can do the 8 reevaluation or there are specific procedure how to 9 get there. Either you -- because usually not all the 10 structure get effected, there is a small part of the 11 structure that you can either reevaluate or retrofit.
12 MEMBER RICCARDELLA: Retrofit?
13 DR. BOLOURCHI: Yes.
14 MEMBER RICCARDELLA: I see.
15 DR. BOLOURCHI: It is option that we can 16 -- will be discussed by Seabrook.
17 MEMBER DIMITRIJEVIC: I have a risk related, 18 I'm risk specialist, so I really appreciate all of this 19 deterministic evaluation. But, from my point, so, you 20 basically prove that they satisfy licensing basis and 21 capacity of the structure.
22 What I would like to understand is there 23 any, because I know you do this and you will understand 24 it well, is there any risk implication of this?
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169 1 station, same for Westinghouse, on the same seismic 2 area. I'll just ask about seismic, I will ask when 3 this second group comes about other failure modes.
4 So, you have same seismic event and you 5 calculate fragility for the components and structures.
6 Would the Seabrook, with this issue, with ASR issue, 7 would the fragility numbers be different?
8 DR. BOLOURCHI: I haven't calculate the 9 actual fragility calculation for you, but we have --
10 MEMBER DIMITRIJEVIC: What's your feeling?
11 DR. BOLOURCHI: No, no, let me --
12 MEMBER DIMITRIJEVIC: Okay.
13 DR. BOLOURCHI: -- each of our calculation, 14 I am a seismic engineer --
15 MEMBER DIMITRIJEVIC: Yes, that's right.
16 DR. BOLOURCHI: -- by nature, we have 17 calculated all the calculation, original calculation 18 is done by the stick model for the seismic and we review 19 all of that.
20 The total mass is not changed, obviously.
21 The center of gravity, center of the -- we calculate 22 the center fragility and central mass for each of the 23 structures, to make sure the original stick model still 24 is valid.
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170 1 which Seabrook, I assume that they have done the PRA 2 work, would not be impacted on that. And --
3 MEMBER DIMITRIJEVIC: But, for example, you 4 said that there is a change in seismic gap. This can 5 impact the impact of the one structure and that is --
6 so, you think really that ASR would not impact any risk, 7 seismic risk calculation?
8 DR. BOLOURCHI: No, no, we calculate 9 actually the maximum calculated value for what is the 10 required seismic gap? And we calculate that, I know, 11 on a very conservative way.
12 Originally, they did all the seismic gap, 13 they put everything at three inches. And most of the 14 calculations are less than half an inch, that you 15 require.
16 We are recalculating those to confirm, at 17 an area that was abutting against each other, that was 18 one of our recommendation, because it would impact the 19 seismic, original seismic evaluation.
20 Therefore, we recommended to cut the 21 missile shield and they did cut it and the requirement 22 was to have at least one inch of gap and to maintain 23 that, to maintain the same code requirement and also, 24 the fragility that would impact on that.
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171 1 risk implication, that's what you're saying, right?
2 This phenomena doesn't have a risk implication 3 whatsoever?
4 MR. BELL: Maybe a way to address your 5 question at a higher plane, if this is appropriate, 6 we could go through the analysis and all the processes, 7 the structural performance, including fragility, would 8 be in line with a code-compliant structure.
9 MEMBER DIMITRIJEVIC: All right.
10 MEMBER RICCARDELLA: I believe you did the 11 analysis using the original design-basis response 12 vector for SSE.
13 I'm sure you're probably aware that the 14 updated response vector, as part of the Central and 15 Eastern United States Seismic Study, showed a 16 considerably reduced response vector, in the one to 17 ten hertz range. I'm sure you're probably aware of 18 that.
19 DR. BOLOURCHI: I think Seabrook did the 20 PRA work already?
21 MR. BROWNE: Yes, I would have to reach out 22 for the PRA work.
23 MEMBER RICCARDELLA: Well, I'm just saying 24 that might be some additional margin that you could 25 take --
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172 1 DR. BOLOURCHI: Yes.
2 MEMBER RICCARDELLA: -- advantage of in --
3 DR. BOLOURCHI: We have additional margin.
4 MEMBER RICCARDELLA: -- the event that you 5 have the 1.2, an issue with the 1.2.
6 MR. BELL: The exercise here was to check 7 conformance to the original design criteria. To the 8 extent that was conservative, that's built into the 9 present exercise.
10 CHAIRMAN SKILLMAN: Let's move along, 11 folks.
12 DR. BOLOURCHI: Okay, next slide.
13 Therefore, in conclusion, we have evaluated or we are 14 completing evaluating all seismic Category I structure 15 using the consistent methodology applicable to all of 16 them.
17 And we provided the threshold for each 18 building that we will complete. Therefore, and defined 19 action require to make sure each structure meet the 20 code of record. And that conclude our part of the 21 evaluation.
22 CHAIRMAN SKILLMAN: Thank you very much.
23 Members, before we release this team of consultants, 24 have you any questions, please? Hearing none, it's 25 -- Ron, go ahead.
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173 1 MEMBER BALLINGER: What's the uncertainty 2 on the 1.2?
3 DR. BOLOURCHI: Generally, the -- I know 4 some of these buildings by heart now. Some of the 5 buildings that is 1.2 is on the conservative side, I 6 can very easily, if I do more evaluation on that, can 7 easily, because the controlling part is low grade and 8 that's why we limited to above grade, and we -- easily, 9 we have more margin. We have tried to be conservative 10 on this evaluation.
11 MEMBER BALLINGER: So, it's better than 1.2?
12 DR. BOLOURCHI: It's better than 1.2.
13 MEMBER BALLINGER: Not lower than 1.2?
14 DR. BOLOURCHI: No.
15 CHAIRMAN SKILLMAN: Okay. Where are we on 16 presentations? Do we have another presentation from 17 --
18 MR. BROWNE: Mr. Chair, we have a short, 19 I'll call it a short presentation on the program, but, 20 I'll talk to Ed, but I think in the -- there's several 21 slides at the backside of this next section that involve 22 the license amendment that I think would be redundant 23 and I think the Subcommittee likely understands the 24 construct of that.
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174 1 the program a bit with Mr. Carley and Ms. Hulbert, and 2 then, we'll turn it over.
3 CHAIRMAN SKILLMAN: Absolutely. Let's do 4 that and let's get moving. Thank you. Please go 5 ahead.
6 MR. CARLEY: Thank you. I am Edward Carley, 7 the Engineering Supervisor for License Renewal and 8 I was part of the project team for the resolution in 9 the licensing basis for ASR-affected concrete 10 structures.
11 As our final segment for today, we will 12 discuss the approach for managing the aging effects 13 of ASR-affected concrete structures at Seabrook 14 Station. If we can just go ahead one slide?
15 Ms. Jackie Hulbert will provide the details 16 of our enhanced Structures Monitoring Program and ASR 17 monitoring implementation. And as we had just 18 discussed, we will probably just skip over the summary 19 of our current licensing actions, as we've discussed 20 those quite a bit today. So, just two more slides 21 ahead.
22 So, referring back to the graphic you've 23 seen throughout this presentation, the Structures 24 Monitoring Program takes the bounding conditions of 25 the large-scale test program and the threshold NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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175 1 monitoring limits from the structural evaluation and 2 implements an overall ASR Aging Management Monitoring 3 Program that is integrated into the site's 4 comprehensive Structures Monitoring Program.
5 As shown by this graphic, the -- if and 6 when limits are approached or a new condition is 7 identified, there is a feedback loop to update the 8 structural evaluations. And as shown on the graphic, 9 the program currently implemented will continue into 10 and through the period of extended operation.
11 And on that, I'll turn it over to Ms.
12 Hulbert.
13 MS. HULBERT: Hi, I'm Jackie Hulbert. I'm 14 the Structures Monitoring Program Engineer at Seabrook.
15 As Ed had mentioned just a second ago, we 16 have developed a comprehensive Structures Monitoring 17 Program that addresses the typical Maintenance Rule 18 portion, as well as the identification, evaluation, 19 and monitoring of alkali-silica reaction affected 20 concrete structures and associated systems, 21 structures, and components.
22 Our Structures Monitoring Program 23 incorporates the results and the respective monitoring 24 limits from both the large-scale testing program, as 25 well as the structural evaluations.
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176 1 In addition, Seabrook Engineering, we have 2 performed both interdisciplinary and 3 cross-disciplinary training on ASR and ASR-induced 4 building deformation to bring awareness to the Station.
5 We have developed web-based training for 6 all badge personnel onsite, as well as we provide 7 focused training for departments. Next slide.
8 So, I know this slide's busy, and the next 9 slide will be as well. The intent is not for you to 10 be able to read every word.
11 So, at Seabrook, we developed a database 12 in which we enter all of the deficiencies, the 13 monitoring results, et cetera, that derive from the 14 inspections performed in accordance with our Structures 15 Monitoring Program.
16 The database mimics the different sections 17 of our program. As you can see, we have the Maintenance 18 Rule portion, ASR expansion monitoring, the ASR-induced 19 building deformation monitoring, and equipment 20 impacted by building deformation, and groundwater 21 monitoring.
22 The database we use as a tool or an aid, 23 that we use to track our monitoring results, and in 24 addition, the other departments onsite have access to 25 this, so they can use this for their information. Next NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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177 1 slide.
2 Like I said, this is busy. This just gives 3 you a glimpse of what's included in our database. It's 4 a partial view of all the observations identified under 5 the different sections of our program.
6 This is particular to our residual heat 7 removal vaults. Examples captured in our program 8 include, like, corrosion of the steel components, 9 concrete cracks, ASR, degraded building seals, 10 coatings, et cetera.
11 So, the margin parameters in acceptance 12 criteria for ASR-affected concrete structures are 13 driven by the results from the large-scale testing in 14 the structural evaluations, as previously mentioned.
15 Expansion due to ASR is tracked via 16 in-plane expansion measurements, in the form of either 17 combined cracking index or pin-to-pin.
18 The through-thickness expansion is tracked 19 via material testing in the installation of the borehole 20 extensometers. And then, we also track volumetric 21 expansion.
22 The limits for ASR expansion, like I said, 23 were derived from the large-scale testing program.
24 The monitoring frequency is driven by the severity of 25 the in-plane expansion.
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178 1 In-plant expansion measurements are 2 performed either on a six-month or a 30-month basis.
3 Through-thickness expansion measurements are 4 performed on a six-month basis, as well as the 5 volumetric.
6 The parameters to be monitored for 7 structural deformation due to ASR are building-specific 8 and their associated thresholds are derived from the 9 structural evaluations.
10 Examples of parameters in which we monitor 11 can include the measurements of seismic gaps between 12 structures, the annulus width measurement between our 13 containment structure and containment enclosure 14 structure. We do plumbness measurements, in-plane 15 expansion measurements. We sound for drumming areas.
16 And a slew of other things.
17 The monitoring frequency for the 18 deformation parameter monitoring is based on the stage 19 in which the building was analyzed under.
20 So, as previously mentioned, Stage One 21 structures are monitored every 36 months. Stage Two 22 structures are monitored every 18 months. And Stage 23 Three are monitored every six months.
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179 1 way of applying what we call an administrative 2 monitoring action limit, and that's applied to the 3 threshold limits that were developed through the 4 structural evaluations.
5 The admin limit provides time to perform 6 additional inspections, to ensure limits are not to 7 be approached prior to the next inspection interval, 8 and to initiate corrective actions if warranted.
9 In addition, the Structures Monitoring 10 Program ensures that if a new deficiency is noted or 11 if a deficiency worsens that could potentially have 12 an impact on structural evaluations, that it is entered 13 into our Corrective Action Program and evaluated 14 appropriately.
15 So, monitoring locations. As previously 16 mentioned, we monitor ASR expansion volumetrically, 17 both in-plane and through-wall.
18 We currently have a total of 136 locations 19 in which we monitor in-plane expansion, as it relates 20 to the large-scale testing, and we have an additional 21 21 grids established that derive from the building 22 deformation evaluations.
23 Through-thickness expansion, like 24 previously mentioned, is determined by establishing 25 what the expansion is to-date and then, using the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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180 1 borehole extensometers to track any potential expansion 2 going forward.
3 To establish the expansion to-date, we 4 extracted concrete cores, performed material testing, 5 and correlated the results back to the large-scale 6 testing program.
7 We currently have a total of 48 8 extensometers installed in various structures and we've 9 taken approximately 200 cores and performed material 10 testing on all of them.
11 As mentioned before from MPR, we test all 12 cores for compressive strength and for modulus of 13 elasticity.
14 Actually, Seabrook -- so, for the material 15 testing, Seabrook actually brought the capability to 16 test cores onsite. We set up a lab that mimicked the 17 lab at the Ferguson Structural Engineering Laboratory.
18 And we developed procedures in accordance 19 with the respective ASTM standards for the obtaining 20 and the performing of the material testing on the 21 concrete cores. Next slide.
22 The monitoring locations and parameters 23 related to the structural deformation, like I said, 24 are derived from the structural evaluations and are 25 captured in our program.
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181 1 This slide shows some examples of the 2 monitoring we performed. Top left photograph shows 3 how we perform seismic gap measurements between 4 structures.
5 Top right is, we have these plastic 6 Avongard crack gauges installed on specific cracks 7 throughout certain structures, to monitor any 8 additional crack width or worsening of said cracks.
9 We also monitor in-plane expansion, like we mentioned, 10 via both CCI and the pin-to-pin.
11 And we measure, like I said, between 12 structures, like the bottom right, the annulus between 13 the containment enclosure building and the containment 14 structure. Next slide.
15 With our ongoing monitoring, we have 16 established that the current ASR expansion levels are 17 within the large-scale testing limits and our 18 structures and the associated building deformation 19 monitoring parameters are within threshold limits 20 established from the structural evaluations.
21 As we had mentioned before, ASR expansion 22 at Seabrook is slow. We have been monitoring expansion 23 since 2011 and our monitoring frequencies are 24 sufficient to ensure that the limits are not approached 25 prior to the next inspection interval.
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182 1 MR. SCHULTZ: Jaclyn, how much margin do 2 you have on that statement? In other words, you know 3 it's not going to happen before the next inspection, 4 but if it did happen then, I mean, it would be nice 5 if you had two intervals, comfort level for at least 6 two intervals.
7 Because a reevaluation, for example, could 8 take six months, it was stated. Action take to correct 9 an issue that was identified and then, inspection, could 10 take even longer. So, how --
11 MS. HULBERT: Correct. With --
12 MR. SCHULTZ: -- much margin do you have?
13 Do you feel, with the slowness and --
14 MS. HULBERT: That's a loaded question.
15 MR. CARLEY: So, not getting back into what 16 we discussed in the closed session, right now, the 17 in-plane limit is at, the highest location is 2.46.
18 So, significantly lower than the overall limits.
19 Volumetric is at 0.78, so if you can 20 remember the close limits, but significantly lower.
21 So, even in our worst case situations, we still have 22 quite a bit of margin to all areas.
23 MEMBER RICCARDELLA: That's for the first 24 bullet, relative to the large-scale testing. It seems 25 to me, the second bullet is the more limiting.
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183 1 MR. CARLEY: The more -- the threshold 2 limits are our limiting case.
3 MEMBER RICCARDELLA: Like that 1.2, have 4 you had multiple measurements on the one that has the 5 threshold factor of 1.2, to see how that's progressing?
6 MR. CARLEY: That is the CEB, and that is 7 the one that we have the most data on. And 8 particularly, on seismic gaps, and we see very little 9 to no --
10 MEMBER RICCARDELLA: Can you --
11 MR. CARLEY: -- movement on that.
12 MEMBER RICCARDELLA: Okay.
13 MR. CARLEY: Liying can probably elaborate 14 on that, because she takes those measurements for us, 15 if you need more detail.
16 MS. HULBERT: But like I said, we have this 17 admin limit that we apply to it as well, to give us 18 more time to react.
19 MEMBER MARCH-LEUBA: But I don't know how 20 to compare that 1.2, which is a 20 percent margin on 21 the load factor, which is a threshold, how to compare 22 to how much cracks you can have. Can you double the 23 number of cracks and it still be okay on that?
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184 1 it's in the wrong units. And I have no idea how to 2 convert it.
3 MEMBER RICCARDELLA: It depends on how fast 4 it's changing. I mean, if they've taken measurements 5 in the last three six-month intervals and it's only 6 gone from maybe 1.1 to 1.1, then you're not too concerned 7 about reaching 1.2.
8 MEMBER MARCH-LEUBA: But what I'm hearing 9 on the top bullet units is that for 30 years, it has 10 grown 2.5 millimeters. And it can -- they can tolerate 11 seven.
12 MEMBER RICCARDELLA: Yes.
13 MEMBER MARCH-LEUBA: So, that -- over there, 14 you don't have a problem. What I don't know, how to 15 compare 1.2 to something in those units.
16 MEMBER RICCARDELLA: Yes. It probably 17 depends on the structure.
18 CHAIRMAN SKILLMAN: Let's move. Something 19 to think about in your program.
20 MR. SCHULTZ: Another question was, it 21 sounds as if Seabrook has taken over all of the 22 inspection, Seabrook personnel are doing all the 23 inspections that were done by --
24 MR. COLLINS: No, SGH has continued to --
25 MR. SCHULTZ: Their work?
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185 1 MR. COLLINS: -- perform those inspections.
2 We do have a long-range plan, because SGH is not cheap, 3 sorry you guys. So --
4 MR. SCHULTZ: No, I understand that.
5 MR. COLLINS: We do have -- we have just 6 opened up three positions in our design group, civil 7 design group, to hire in individuals to -- and SGH has 8 just said they'll help train these individuals to do 9 the work that SGH is now performing. We intend to have 10 a transition to bring all those activities in-house.
11 MR. SCHULTZ: Is there a clear qualification 12 program that is required to do this kind of inspection?
13 MR. COLLINS: We'll set up a qualification 14 program. I know SGH has their own qualification 15 program, that's something we're going to have to go 16 through the transition period with.
17 MR. SCHULTZ: Okay, thank you.
19 MR. SCHULTZ: Okay, good.
20 MR. CARLEY: -- has the requirements.
21 MR. SCHULTZ: Thank you.
22 MEMBER REMPE: Remind me, what is the admin 23 limit, what percent of the --
24 MS. HULBERT: Ninety-seven percent.
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186 1 three percent additional margin?
2 MS. HULBERT: But this is on top of the 3 conservatism that's already built into the model.
4 MEMBER REMPE: Thank you.
5 MEMBER DIMITRIJEVIC: May I ask a question?
6 Why do we worry about those small details if there 7 is no risk implication of that? They just told us it 8 doesn't change any risk, so why we are so concerned 9 of is it 1.2 or 0.9? What is going to change from the 10 risk perspective?
11 MR. SCHULTZ: Maybe if you go to Slide 18, 12 if you're ready to do that. I mean, there are 13 modifications that are happening to the facility 14 because of this program. And they're determined based 15 upon the analyses and the inspections.
16 CHAIRMAN SKILLMAN: Vesna, it goes back to 17 the design basis. This is an issue where the licensee 18 must demonstrate that the loads imposed by ASR, combined 19 with other loads, do not exceed the licensed load 20 limits.
21 And so, while there might not be any 22 significant risk implications, there is most certainly 23 a license implication. And this is very much a license 24 demonstration of loading capacity, so that the facility 25 is within the bounds established by its license.
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187 1 MEMBER KIRCHNER: But, Dick, it's more than 2 that. I mean, if they exceed the limits from the codes, 3 then you can't make assumptions about success of the 4 particular structure to withstand, let me just pick 5 on one of the inputs, seismic loading, if you don't 6 meet code within the margin that's required.
7 So, it does turn back to a risk impact, 8 because then, when you do your PRA, you pretty much 9 need to assume that with that load and that degradation, 10 that piece of equipment does not meet its function.
11 It becomes very important with seismic Cat I components 12 and structures.
13 MEMBER DIMITRIJEVIC: I understand this, 14 but what I'm saying, this is just setting limits, 15 triggering limits. We are not anywhere close not to 16 meet -- okay.
17 MEMBER REMPE: So, earlier --
18 MEMBER DIMITRIJEVIC: I'm a probabilistic 19 person, I'm staying out of this discussion.
20 MEMBER REMPE: Well, earlier today, you 21 asked, have they reevaluated fragility? And in my 22 mind, I was wondering, have you gone through and thought 23 about what seals, other seals due to building 24 deformation, might be impacted?
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188 1 done on that? I mean, it's not just fragility, it's 2 penetration seals, and has that been carefully thought 3 through all the way?
4 MR. CARLEY: Yes. And seals are inspected 5 as part of our monitoring program, along with seismic 6 gaps, fire seals, we're looking at those and make sure 7 --
8 MEMBER REMPE: All of them?
9 MR. CARLEY: Yes, those are all incorporated 10 into our Structures Monitoring Program, as part of 11 structures monitoring, but also as part of the 12 deformation review, to verify that those seals are 13 staying intact through --
14 MEMBER REMPE: So, you're monitoring the 15 deformation that could impact all those -- these kind 16 of questions are good. I appreciate it, just because 17 it would be hard to divine that from what we were given 18 to read in advance.
19 MEMBER DIMITRIJEVIC: Well, I was going to 20 go in more details, like the electrical vaults or the 21 pipe vaults and things. But then, I said, if they're 22 not impacted in seismic area, there is nothing else 23 which will impact it.
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189 1 demand versus the others. So, I mean, there is so many 2 different failure modes can be introduced here, but 3 if they are not going to fail under seismic, then --
4 MR. CARLEY: Yes, and I think the true 5 answer, as Chairman Skillman indicated, as long as we 6 stay in our limits, our licensing limits, there is no 7 increased risk. I mean, that's what we're looking at.
8 CHAIRMAN SKILLMAN: Let's move on, we're 9 almost there, let's go.
10 MR. CARLEY: If it's all right with 11 everyone, we'll skip over the review of the license 12 amendment and the license renewal application and move 13 on to Slide 15.
14 This is just the summary of our closure 15 of the open item from 2012 in the SER, for Structures 16 Monitoring Program.
17 We've updated to augment the existing 18 Structures Monitoring Program by the addition of 19 plant-specific Alkali-Silica Reaction and Building 20 Deformation Aging Management Programs.
21 And we've also added a tie in our IWL 22 Program to our Structures Monitoring Program, to 23 address ASR.
24 CHAIRMAN SKILLMAN: Okay.
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190 1 has implemented a program that effectively evaluates 2 and manages the aging effects of ASR on affected 3 concrete structures and associated components.
4 And on that, I'll turn it back over to Mr.
5 Collins for conclusions.
6 MR. COLLINS: Thanks, Ed. Next slide, 7 please. So, you'll recognize the flowchart from my 8 opening discussion of the background of ASR at Seabrook 9 Station.
10 We have presented a detailed discussion 11 on each aspect of the graded approach that has been 12 developed in response to the identification of ASR in 13 our seismic Category I concrete structures.
14 The flowchart explains the integrated 15 approach that NextEra Seabrook has developed. All 16 ASR-related efforts fit together and all results, 17 conclusions, lessons learned, are all incorporated 18 ultimately into our Structures Monitoring Program.
19 Next slide.
20 And then, these are the 19 structures that 21 we have completed a seismic Category I structural 22 evaluations. Listed under the actions required on the 23 right-hand column are activities moving forth for 24 retrofit for areas that are outside the limits or bounds 25 of the analysis, and we are taking appropriate actions NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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191 1 in those cases.
2 MEMBER MARCH-LEUBA: Before you move to the 3 next one --
4 MR. COLLINS: Sure.
5 MEMBER MARCH-LEUBA: -- I understand you 6 will be coming back next month, I believe, for the full 7 Committee, to get our coveted letter. I would ask you 8 a favor.
9 If you can present this slide to us again 10 and add an extra column, which is the percent 11 contribution to the load by ASR? Because those 1.2s 12 at the bottom look really bad, but maybe the ASR only 13 contributes five percent to it.
14 If it's not too much work, which I mean, 15 you have the numbers, I would add how much did -- what 16 was the contribution of ASR to that threshold?
17 MR. COLLINS: I don't see that as being 18 unreasonable, we'll work on that.
19 MEMBER MARCH-LEUBA: It would help me a lot, 20 understand how relevant ASR is to this problem.
21 MR. COLLINS: Understood, thank you.
22 MEMBER MARCH-LEUBA: And if you could send 23 it -- if you have it done three days in advance, don't 24 send it the night before at midnight, so we can read 25 it.
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192 1 MR. COLLINS: We'll work through it to make 2 sure you have reasonable time to review the information.
3 But next slide, please. Again, this is a conclusion 4 statement, to rack up, close up the discussion for 5 today.
6 In conclusion, NextEra has completed a 7 comprehensive effort to conduct large-scale testing 8 to understand the structural implications of ASR, 9 developed methodology for evaluation of ASR-affected 10 structures, evaluated ASR-affected structures to the 11 degree I just showed you in the previous slide, and 12 have developed monitoring strategies for ASR-affected 13 concrete and associated systems, structures, and 14 components.
15 Completed structural evaluations 16 demonstrate seismic Category I structures comply with 17 the licensing basis, as amended by the LAR. We've shown 18 that ASR progression is slow.
19 Ample margin exists before large-scale 20 expansion limits would be approached. Monitoring 21 frequency are based on relative margin to the limits 22 and thresholds.
23 And our efforts provide reasonable 24 assurance that the structures will continue to perform 25 their intended function, consistent with the licensing NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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193 1 basis, again, as amended by the LAR, through the period 2 of extended operation.
3 If there's no more questions, this will 4 end our presentation for today.
5 CHAIRMAN SKILLMAN: Okay. So, colleagues, 6 any question or questions at this point for NextEra 7 or either of their consultant teams?
8 MEMBER KIRCHNER: What is, I don't see it 9 here in the rack up, in the summary, how does the 10 containment margin, how would you, not demonstrate, 11 in your -- as a result of your program and your analysis, 12 what would you say about the containment?
13 You've got threshold factors for all these 14 seismic I categories --
15 MR. COLLINS: That --
16 MEMBER KIRCHNER: -- that CV, is that the 17 1.8, there?
18 MR. COLLINS: Yes.
19 MEMBER KIRCHNER: Is that it?
20 MR. COLLINS: That's correct, sir.
21 MEMBER KIRCHNER: Okay, thank you.
22 MEMBER RICCARDELLA: And the CV, I don't 23 see in this table.
24 MR. COLLINS: Sorry?
25 MEMBER RICCARDELLA: I'm sorry, I don't see NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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194 1 the --
2 MEMBER KIRCHNER: It's down here, I think, 3 there.
4 CHAIRMAN SKILLMAN: It's about six from the 5 bottom.
6 MEMBER RICCARDELLA: Okay. All right, 7 thank you.
8 CHAIRMAN SKILLMAN: Colleagues, any other 9 questions for --
10 MEMBER MARCH-LEUBA: Yes, to remind me, the 11 containment is the one that almost didn't have any ASR?
12 So, that's where the percentage I'm asking you will 13 help, because you will see no difference before and 14 after. I hope.
15 MR. COLLINS: We'll apply that to all the 16 items I have listed here.
17 CHAIRMAN SKILLMAN: Okay. Going once?
18 Going twice? NextEra and MPR, and the team from Boston, 19 thank you very much.
20 Not being trite, we've saved the best for 21 last. We've got the NRC staff to come up and they've 22 been patient all day long.
23 We did take a break an hour ago. I'm going 24 to ask that we move into the next phase of the 25 presentation. And if individuals need to disappear NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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195 1 for a few minutes, would you please do that, but let's 2 keep this meeting going, because we really would like 3 to wrap up at a reasonable hour. Please.
4 MR. DONOGHUE: Yes, Chairman Skillman, I'll 5 tell you that the staff, embracing transformation, has 6 looked through its slides -- come on up, come on up 7 -- and will streamline as they can, but we're ready 8 to answer all the Subcommittee's questions.
9 CHAIRMAN SKILLMAN: Thank you, Joe. So, 10 Angela, are you the leader today?
11 MS. BUFORD: Yes.
12 CHAIRMAN SKILLMAN: Thank you. Let's just 13 hold for a minute here. Ladies and gentlemen, let's 14 get started. Angela, are you ready?
15 MS. BUFORD: Yes.
16 CHAIRMAN SKILLMAN: Yes, ma'am.
17 MS. BUFORD: Okay. There we go.
18 CHAIRMAN SKILLMAN: Let us begin.
19 MS. BUFORD: Okay, great. My name is Angela 20 Buford. I am a Structural Engineer in the NRC's Office 21 of Nuclear Reactor Regulation. I'm also the technical 22 lead for the Seabrook license renewal ASR issue.
23 Seated with me at the table are Bryce 24 Lehman, he is another Structural Engineer in NRR. And 25 also, Nik Floyd, who is a Senior Reactor Inspector in NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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196 1 Region I.
2 Also at the table is actually George 3 Thomas, who won't have a speaking role today, but he 4 participated in the review of the license amendment 5 request.
6 Like Joe said, in the interest of time, 7 we're going to trying to streamline what we say and 8 not repeat some of the information that was already 9 given to you.
10 But as it relates to the staff's 11 impressions and our review, some of the information 12 may overlap, just so that you can get a feel for our 13 reactions and our actions.
14 As you guys know, this issue has definitely 15 evolved over time. I've actually been involved since 16 day one, so that's eight years.
17 And a lot of iterations of the LRA were 18 not deemed sufficient by the staff, because we weren't 19 able to come to a reasonable assurance conclusion, 20 because there was testing being done, there was not 21 enough information, and we weren't able to have 22 confidence that ASR would be effectively managed.
23 After extensive work by the licensee and 24 extensive review from the staff, we are now able to 25 have that reasonable assurance conclusion and can now NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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197 1 close that open item. Next slide, please.
2 This slide just presents an overview of 3 what we'll be discussing today. So, I don't need to 4 read it. But I'll just begin with the overview and 5 then, I'll turn it over to my colleagues.
6 Oh, you know what?, this is Butch's 7 presentation, if you just scroll through? Okay, there 8 we go. Because this is what we'll be covering. And 9 again, we'll try to pare down as necessary. Next slide.
10 I will just highlight that, because ASR 11 is a complex phenomenon and it's the first identified 12 in the nuclear industry in the U.S., the NRC assembled 13 a large team of individuals to help coordinate and 14 evaluate the issue, and that's including the 15 organizations that are up on that slide.
16 It's the Seabrook ASR Issue Technical Team, 17 and we've had extensive coordination in assessing and 18 sharing information along the way. Next slide.
19 So, a lot of this slide is history, so 20 unless you have any questions on it, I will skip through 21 to the next. We know how ASR was found and that 22 operability determinations were developed. Okay.
23 So, again, on this slide, NextEra covered 24 most of why ASR occurred. But I will highlight the 25 last bullet, that the Seabrook Health Monitoring NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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198 1 Program for Systems and Structures, which was a 2 precursor to the Structures Monitoring Program, which 3 is required by the Maintenance Rule, did not then have 4 a process for periodic reassessment to assure that all 5 failure modes were identified and monitored.
6 Since then, NextEra has adopted ACI 341.3R, 7 which includes guidance for monitoring all aging 8 effects for concrete, including active cracking, such 9 as ASR.
10 CHAIRMAN SKILLMAN: I would like to just 11 make an observation, as I've been preparing for this 12 meeting for about six or eight weeks.
13 What I finally tumbled to, when I was 14 thinking about 50.65, Maintenance Rules, Structures 15 Monitoring, and all of the experience I have had, I 16 was asking myself, how did this slip through the crack?
17 And the answer that I'm comfortable with, 18 whether it's a good answer or not, is, this is an active 19 element of a passive component.
20 And we normally don't think about a passive 21 component having an active mechanism that has the 22 potential to degrade that component to the point where 23 it is no longer within its design basis.
24 So, at least in my own mind, in an attempt 25 to not point fingers or create fault or to suggest NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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199 1 anything untoward, this one slipped by a lot of people 2 in the whole industry.
3 This isn't just something that happened 4 in a little corner of New Hampshire, this could have 5 slipped by anybody. But it does raise the question, 6 are there any other passive components out in our realm 7 that have an active element that we're not looking at?
8 And I don't know the answer to that 9 question, but -- well, we know about NVT, we know about 10 all kinds of chemical issues, but here's truly one 11 that's a sleeper. It's really under everyone's radar.
12 But it just strikes me that a unique feature 13 of this is, here is a passive component that has an 14 active mechanism within it, and none of us saw it coming.
15 MS. BUFORD: Yes.
16 MR. DONOGHUE: Chairman Skillman, this 17 isn't really an answer to your question, but I'll just 18 emphasize that the staff plays close attention to 19 operating experience. I know the industry does.
20 And one of our jobs in the Division of 21 Materials and License Renewal, they were put together 22 for a reason, because a lot of those degradation 23 mechanisms are material based, material engineering 24 based.
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200 1 experience, that's how we think we're going to catch 2 them as early as we can.
3 CHAIRMAN SKILLMAN: Good, thank you, Joe.
4 Not philosophizing, I just -- I found it important 5 to communicate that, because in a way, it tells me, 6 this is how we got here. This really snuck up on 7 everybody.
8 MS. BUFORD: Yes, and it actually happened 9 during the review for license renewal, so that was a 10 focused review, specific to that application.
11 Under the reactor oversight process 12 requirements, NextEra performed an extent of condition 13 review and prompt operability determinations and 14 concluded that, from a regulatory standpoint, the 15 affected structures were operable, but degraded, and 16 nonconforming, because ASR was a degradation mechanism 17 that was not taken into account in the then current 18 licensing basis.
19 The prompt operability determination 20 analyses assumed that the Seabrook design equations 21 remained valid for concrete affected by ASR and used 22 a reduction in capacity for structural limit states 23 such as shear and compressive strength.
24 Regional inspectors and Headquarters 25 experts reviewed the operability determinations. The NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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201 1 NRC staff concluded that the analyses used conservative 2 load factors to ensure that there was sufficient 3 engineering margin.
4 Secondly, inspectors and experts from 5 Headquarters performed field walkdowns and confirmed 6 that there were no significant indications of 7 deformation, distortion, or rebar corrosion.
8 Third, that the ASR was localized and was 9 occurring slowly, based on existing operating 10 experience. And then, finally, the degradation was 11 being monitored.
12 And those operability determinations are 13 still in place and are being resolved under the license 14 amendment request.
15 In response, NextEra made commitments to 16 address the issue of ASR-affected concrete and to 17 confirm those commitments, the staff issued a 18 confirmatory action letter, or CAL.
19 The CAL referenced NextEra's planned 20 large-scale testing program and you heard about that 21 a lot today.
22 At the time that the applicant was 23 proposing the testing program, they wanted to define 24 crack limits for ASR and to examine ASR behavior in 25 a structural context, as opposed to an unreinforced NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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202 1 core bore samples.
2 Under the license renewal process, in June 3 of 2012, the NRC staff issued its safety evaluation 4 report with open items. The document discussed the 5 Seabrook operating experience related to the impact 6 of ASR and included one open item related to the need 7 for ASR to demonstrate that the aging of structures 8 would be adequately managed during the period of 9 operation, extended operation, despite ASR.
10 The Region, during its inspection 11 procedure, 71002 Inspection, came to the same 12 conclusion. And such that the NRC staff did not find 13 that the structures could be effectively managed for 14 the aging effect, given the proposed monitoring.
15 Shortly after the SER with open items was 16 issued, NextEra supplemented it's license renewal 17 application to include a plant-specific ASR monitoring 18 program.
19 This was also the time frame that the SAITT, 20 the technical team, was formed to allow for effective 21 alignment of Agency positions. Next slide.
22 As discussed previously, NextEra's prompt 23 operability determination evaluations used a 24 conservative loss of structural capacity.
25 The NRC, with input from an independent NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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203 1 expert on structural engineering, independently 2 verified that there was reasonable assurance that the 3 ASR-affected structures at Seabrook maintained 4 adequate margin to continue to perform their intended 5 functions.
6 However, since the prompt operability 7 determination evaluations were based on conservative 8 estimates and literature data, the staff understood 9 that NextEra would be initiating a large-scale testing 10 program to determine the actual impact of ASR on the 11 performance of the structures.
12 The NRC, as part of its CAL review, reviewed 13 those plans, and also under the license renewal review.
14 There was a significant amount of back and 15 forth, with the NRC staff asking questions and holding 16 public meetings to understand how the testing program 17 was going to be credited to analyze the structures.
18 Next slide.
19 So, there was a difference in opinion.
20 NextEra viewed the large-scale testing program as more 21 of a research and development effort, to gain 22 information that would help to inform monitoring 23 programs.
24 The NRC position, however, was that if the 25 testing would be used to support the position that ASR NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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204 1 did not have a structural impact, then this would be 2 a new method of evaluation for the current license that 3 would need to be approved by the NRC.
4 Similarly, the staff position with respect 5 to license renewal has always been that if the testing 6 program would be the basis for elements of Aging 7 Management, then that would require a detailed review 8 by the NRC.
9 So, in response, NextEra submitted their 10 license amendment request that included the large-scale 11 testing program and would amend the Seabrook licensing 12 basis to include the findings of that large-scale 13 testing program. Next slide.
14 So, you already know that during routine 15 walkdowns in 2014 and 2015, it was NRC Resident 16 Inspectors that observed degraded seismic and fire 17 seals that appeared to have been caused by differential 18 movement between adjoining concrete buildings.
19 It was determined that ASR caused this 20 additional aging effect through cumulative 21 micro-cracking in ASR-affected structures. In 22 addition, there was discrete large cracks and the 23 effects were not anticipated. They were identified 24 by the NRC as a different consequence of ASR.
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205 1 program did not address specifically how building 2 deformation would affect the ability for structures 3 to perform their intended functions.
4 Therefore, NextEra subsequently developed 5 an additional plant-specific Aging Management Program 6 called the Building Deformation Monitoring Program, 7 to manage this effect.
8 I'll just add that, based on your earlier 9 comments, Mr. Chairman and Dr. Corradini --
10 MEMBER REMPE: I'm short, but I'm right 11 here.
12 MS. BUFORD: Oh, I'm sorry, Rempe, Joy, 13 excuse me. Okay, yes, right. Yes, I couldn't see you.
14 Sorry about that.
15 MEMBER REMPE: Otherwise, we look a lot 16 alike.
17 (Laughter.)
18 MS. BUFORD: Sorry about that, Ms. Rempe.
19 So, I just wanted to add that, based on your earlier 20 comments about the length of time that it's taken from 21 the initial review to get to this point, part of the 22 reason that the staff was not able to reach a reasonable 23 assurance conclusion was our concern that NextEra did 24 not appear to be addressing the potential for ASR to 25 manifest in other ways.
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206 1 So, we didn't have confidence, throughout 2 this process, that monitoring plans that were in place 3 would manage the aging effect in a more holistic manner.
4 MEMBER REMPE: So, that clarifies a question 5 I was going to ask about, this was not anticipated.
6 It sounds like the staff did do some homework and 7 recognized that this could be another effect, because 8 it's in the literature.
9 MS. BUFORD: I think that it definitely came 10 to -- it was a surprise, I think, even to the staff, 11 although in the literature, it does say that ASR can 12 manifest itself in other ways.
13 It's just that that particular way of the 14 building deformation hadn't been identified by the 15 licensee. And it was of concern to the NRC that it 16 was the NRC that identified the issue.
17 CHAIRMAN SKILLMAN: Let me ask this, as I 18 listen to your words and think about what we've learned 19 today, it's logical from my perspective, as a long-term 20 plant person, I'd be looking at buildings, I'd be 21 looking at what the Maintenance Rule would tell me to 22 look at, but the last thing I would be thinking about 23 is that the engineering fill or the concrete that was 24 outside the building was actually imposing a load, 25 causing the building to deform.
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207 1 That would never have crossed my mind.
2 Is that -- when you say, NextEra really didn't latch 3 on to the fact that the buildings were being deformed, 4 as an individual in PE, I'd say, well, I probably would 5 have missed that too.
6 I never would have thought that there would 7 be outside forces that were strong enough to shift my 8 building. Is that kind of what's hiding in here?
9 MS. BUFORD: Well, yes, but I think that 10 our reaction really was that, because if you -- we walked 11 down the plant numerous times. And if you go to the 12 areas, it's clear that something's wrong, right?
13 You've got expanded --
14 CHAIRMAN SKILLMAN: Something's off?
15 MS. BUFORD: Right. So, I guess, our 16 concern really was that people -- this has been 17 potentially going on for years and no one noticed it.
18 So, even if you couldn't predict the 19 backfill to be expanding the structures, it was a little 20 bit just -- it was surprising to us that, walking the 21 plant, no one said, why is that seismic gap smushed?
22 Or isn't that supposed to be three inches, 23 and that looks like it's actually just hitting the other 24 building? So, those kind of symptoms, we were -- it 25 was surprising that those symptoms weren't identified NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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208 1 sooner, really, I think.
2 CHAIRMAN SKILLMAN: I see. Okay, thank 3 you.
4 MS. BUFORD: Okay. This is really already 5 -- you can turn to the next slide, please. This 6 information has already been covered, just that in 7 August of 2016, the license amendment request was 8 submitted to resolve the licensing basis.
9 And also, to provide technical inputs to 10 the license renewal review. The review of the 11 methodology and the large-scale testing was needed in 12 order to come to a reasonable assurance conclusion for 13 license renewal.
14 And so, the staff's review under the 15 license amendment request provided that technical 16 review.
17 And now, I will turn the presentation over 18 to Nik Floyd, who will discuss the Regional inspection 19 and oversight.
20 MR. FLOYD: Thank you, Angie. Good 21 afternoon, everyone. My name is Nik Floyd and I now 22 will discuss the Regional inspection and oversight of 23 ASR at Seabrook, which I have been personally involved 24 with since 2013. Next slide.
25 The roles of the Regional inspections were NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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209 1 initially focused on NextEra's structural assessments 2 of the reinforced concrete buildings affected by ASR.
3 As you heard in some of the previous slides, 4 NRC performed independent reviews to verify that the 5 affected structures were capable of performing the 6 required safety functions and were properly 7 characterized as operable, but degraded and 8 nonconforming.
9 We have continued to perform semiannual 10 inspections to review the Structures Monitoring Program 11 implementation and results and to verify the 12 significant changes, if any, are evaluated for impact 13 on the concrete structures.
14 One of those sensitivities was the fact 15 that this was initially mis-unidentified and then, the 16 identification of building deformation led us to 17 another increased sensitivity, that we need to continue 18 to look at this with a keen eye.
19 The Resident Inspectors also provide 20 insights on new material conditions in the plant, which 21 I'll describe later.
22 In addition to the onsite monitoring, the 23 NRC performed inspections of NextEra's large-scale 24 testing program, to ensure that the results were being 25 appropriately reflected in the operability assessments NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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210 1 and evaluations of ASR-affected structures.
2 The Regional Office has lead the Seabrook 3 ASR Issues Technical Team, as the team's chair. Part 4 of that role has been to ensure a coordinated effort 5 between the Regional inspectors and Headquarters 6 technical staff, when conducting inspections, as well 7 as assisting in some of the technical licensing review 8 audits.
9 We provide insights and observations from 10 each inspection to the NRC inspectors and experts on 11 that team.
12 The Resident Inspectors, who are also at 13 the plant each workday, also participate in these 14 meetings.
15 It was really this collegial knowledge 16 sharing that's led to a comprehensive oversight and 17 has aided the staff during the licensing activities 18 related to ASR.
19 And a lot of that has also included requests 20 for additional information as new issues arise. Next 21 slide.
22 There have been thousands of direct 23 inspection hours by Regional inspectors and 24 Headquarters structural experts related to ASR at 25 Seabrook since 2010.
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211 1 In total, the combined number of 2 inspections at Seabrook and the Ferguson Structural 3 Engineering Laboratory, which is the location of the 4 large-scale testing program, is 32 weeks.
5 Just to note, these figures do not include 6 the separate audits conducted by Headquarters as part 7 of the licensing review activities.
8 The scope of the Regional inspections 9 consisted of reviewing the operability determinations, 10 the confirmatory action letter team inspections, 11 Resident Inspector samples specifically looking at ASR, 12 as well as the semiannual onsite inspections focused 13 on the ongoing monitoring and corrective actions for 14 ASR. Next slide.
15 Since 2010, the Regional inspections have 16 focused on NextEra's performance to fully identify 17 the effects of ASR on Seabrook structures, to evaluate 18 the condition with sufficient technical detail, and 19 to resolve the nonconforming condition.
20 We have closely monitored NextEra's 21 response to ASR, from the initial identification during 22 the petrography of concrete samples to the 23 implementation of ongoing corrective actions, which 24 would include enhancements to the onsite monitoring 25 programs.
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212 1 I'll now discuss a few of those key 2 observations from this experience.
3 During the NRC's initial oversight of ASR 4 at Seabrook, the inspectors identified concerns 5 regarding the long-term operability of the structures 6 affected by ASR.
7 This was understandable, because the 8 various characteristics of concrete affected by ASR 9 and the related effects on other elements of the 10 structure, such as rebar, due to groundwater 11 in-leakage, and also the progression rate of ASR at 12 the site, were not well understood.
13 Several early inspection findings related 14 to inadequate operability determinations, to fully 15 evaluate the ASR impact with available information.
16 It was really this long-term impact concern 17 that led to a public meeting with NextEra staff and 18 to the NRC subsequently issuing a confirmatory action 19 letter, with one of NextEra's commitments being a time 20 line of resolution of actions and plans to conduct a 21 large-scale testing program.
22 Just a quick note, I'll provide --
23 MR. SCHULTZ: Excuse me, just to clarify, 24 this leads back then to the statement on the previous 25 slide that all of the ten noted shortcomings were all NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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213 1 low significance or very low significance, is what you 2 represented there.
3 And so, that was the earlier finding and 4 then, as time went on, it was determined that this really 5 is a long-term programmatic problem that needs to be 6 seriously considered.
7 MR. FLOYD: Yes, that would be correct.
8 So, some of our early inspection findings, back in the 9 2011 time frame, were really the initial identification 10 of ASR and what that impact was to the sites.
11 Another one would be with the condition 12 monitoring program for the Maintenance Rule. They 13 weren't really evaluating and putting that back into 14 the program for evaluation.
15 I think part of that was growing pains, 16 trying to understand what the issue was, and that led 17 to additional NRC questions and, inevitably, a public 18 meeting and issuance of the CAL, to fully understand 19 the impacts.
20 Some of those impacts were completing 21 operability determinations on all the affected 22 structures.
23 MR. SCHULTZ: Yes, that's to be appreciated.
24 I thank you.
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214 1 large-scale testing program implementation, Bryce will 2 provide more details on that later and I'll have key 3 observations during that portion.
4 In 2014, NRC Resident Inspectors 5 identified several instances of large discrete cracks 6 in the Seabrook residual heat removal vaults.
7 The NRC issued a finding of very low safety 8 significance and inspection report dated August 5, 9 2014, because NextEra did not perform an adequate 10 technical evaluation when it was determined that the 11 crack sizes exceeded the quantitative limits specified 12 in plant procedures, per the Structures Monitoring 13 Program.
14 This is actually one indication of 15 Structures Monitoring Program implementation issues 16 and going back from 2011 to 2014, there was a grouping 17 then, and then, in 2014, a separate grouping, all along 18 the implementation of the program.
19 So, that's what this observation really 20 captures. Also --
21 MEMBER MARCH-LEUBA: Nik?
22 MR. FLOYD: -- this was one early indication 23 of -- oh, sorry.
24 MEMBER MARCH-LEUBA: Those large cracks on 25 the residual heat removal system, were they ASR-induced NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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215 1 or were they other type of stress?
2 MR. FLOYD: Well, that's actually what kind 3 of led to some of the delayed identification. This 4 cracking went along the interior of the vaults and it 5 was in areas that ASR had not been confirmed.
6 And it didn't make sense why that crack 7 was there. Maybe the thoughts were, was it a cold 8 joint? Was it settlement? And it was the lack of 9 evaluation by NextEra staff that led to it not being 10 evaluated and later being confirmed to be the --
11 MEMBER MARCH-LEUBA: And what was the 12 evaluation at the end? Was it ASR or not?
14 MEMBER MARCH-LEUBA: It was ASR?
15 MR. FLOYD: Yes.
16 MEMBER MARCH-LEUBA: So, that's the 17 limiting, not the famous tunnel, but this one?
18 MR. FLOYD: Yes, this is a separate 19 structure that just kind of slipped under the radar.
20 MEMBER MARCH-LEUBA: Well, if you look at 21 the list that we saw at the end of the presentation, 22 is the limiting one, is the one that has a threshold 23 of 1.2.
25 MEMBER MARCH-LEUBA: Yes. That's the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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216 1 limiting place.
2 MR. FLOYD: Next slide, please. Later in 3 2015, during a routine plant tour, NRC Resident 4 Inspectors observed degraded fire seals and changes 5 in seismic gaps that appeared to be caused by 6 differential building movement between the adjoining 7 concrete structures.
8 An example of a degraded seismic gap is 9 shown in the picture. The concrete structures are 10 separated by a seismic gap, that's what's shown by the 11 two black vertical lines there. And the change in the 12 gap at the seal can be seen by the associated cracking 13 and separation between the seal and the structure on 14 the right.
15 We have seen instances of both increases 16 and decreases in gaps, due to the differences in 17 building deformation.
18 As Angie described earlier, NextEra staff 19 initiated a root cause analysis in response to this 20 observation. This confirmed bulk ASR expansion, 21 resulting in building deformation.
22 This building deformation impacted some 23 systems and components attached to the adjoining 24 structures, as evidenced by deformed flexible conduit 25 couplings, reduced seismic isolation gaps, and concrete NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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217 1 spalling. Next slide.
2 An example of equipment impacted by 3 deformation is shown in these two pictures. On the 4 left, you can see deformed flexible conduit couplings.
5 On the right, you can see deformed instrument air 6 piping.
7 Building deformation and its impact on 8 equipment was considered a new phenomenon related to 9 the effects of ASR. NextEra subsequently developed 10 an additional plant-specific Aging Management Program 11 to manage this effect, which you heard earlier.
12 The NRC staff continued to perform 13 inspections and audits at the plant and issued requests 14 for additional information as needed, to determine 15 whether building deformation would be adequately 16 managed during the period of extended operation.
17 Our inspections have verified that the 18 equipment impacted by building deformation has been 19 documented and evaluated by NextEra.
20 We've also reviewed the criteria 21 established for acceptability, as detailed in the 22 Building Deformation Monitoring Program, to ensure that 23 the equipment remains functional. Next slide.
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218 1 of performing their safety function. The NRC has 2 observed significant enhancements to the Structures 3 Monitoring Program since the original identification 4 of ASR at Seabrook.
5 Independent walkdowns by the NRC 6 inspectors have not identified any new undocumented 7 structural deficiencies over the past two years.
8 Based on inspections conducted to-date, 9 NRC inspectors conclude that the licensee is adequately 10 implementing the Structures Monitoring Program and it 11 is appropriately identifying, evaluating, and 12 correcting issues.
13 I will now turn the presentation over to 14 Bryce Lehman to discuss the staff's review of the 15 large-scale testing program, absent any additional 16 questions.
17 MR. LEHMAN: All right, thanks, Nik. I'm 18 going to cover the staff's review of the large-scale 19 testing program and conclusions from the testing 20 program.
21 Obviously, a lot of this, we covered this 22 morning, so if I think we've already addressed it, I'm 23 going to jump over it. If I'm going too fast, just 24 let me know, stop me and ask questions. All right.
25 Next slide, please.
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219 1 And in fact, this one, I think we can skip 2 completely, because it kind of just is an overview of 3 the program and how it was developed, and I think we 4 went over that in detail this morning. So, I'll skip 5 right to the staff's review. All right.
6 The staff reviewed the large-scale testing 7 program, with a focus on the representativeness of the 8 program and the applicability of the program's 9 conclusions to Seabrook structures.
10 The size of the specimens, the 11 configuration of the reinforcement in the materials 12 used in the specimens, were all much more similar to 13 Seabrook structures than existing literature data.
14 The reinforcement in the specimens is 15 similar to Seabrook structures and provides a realistic 16 structural context which accounts for the confinement 17 provided by the reinforcement and the interaction 18 between concrete and reinforcement.
19 The concrete mix design was based on the 20 original Seabrook design specifications. And when 21 practical, materials were obtained from similar sources 22 as the original construction.
23 Furthermore, the test methods used during 24 the testing program were the same as those methods used 25 to establish the empirical design equations in the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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220 1 Seabrook codes of record.
2 Based on these features of the large-scale 3 testing program, especially the structural context that 4 is provided by using large-scale specimens with 5 realistic reinforcement, the staff found that the 6 large-scale testing program is representative of 7 Seabrook structures. Next slide, please.
8 In order to use the through-wall expansion 9 to monitor ASR at Seabrook, it was necessary for NextEra 10 to determine the through-wall expansion of Seabrook 11 structures that had already occurred prior to 12 instrument installation.
13 NextEra reviewed the large-scale testing 14 program data and literature data for multiple 15 properties and determined that reduction in modulus 16 of elasticity was the best material parameter to 17 determine ASR expansion to-date.
18 Using data from the testing program, 19 NextEra developed a correlation between normalized 20 modulus and through-thickness expansion. The staff 21 reviewed the data and noted that the correlation aligns 22 well with the testing data and the available literature 23 data.
24 In addition, the staff noted that a 25 reduction factor was included in the correlation to NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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221 1 account for uncertainty and to provide a conservative 2 expansion value.
3 The staff found this approach to estimating 4 through-wall expansion reasonable. However, since 5 this approach has not be corroborated on Seabrook 6 structures, the staff determined that a license 7 condition was necessary to require future confirmatory 8 actions related to the correlation.
9 MR. SCHULTZ: Bryce, this looks -- these 10 future confirmatory actions, they seem like 11 substantial, substantial evaluations that are going 12 to occur for 2025 and then, ten years subsequent. Is 13 that -- am I getting the right impression?
14 MR. LEHMAN: Yes, I believe that's correct.
15 I mean --
16 MR. SCHULTZ: In other words --
17 MR. LEHMAN: -- NextEra kind of went over 18 it this morning, but it's to --
19 MR. SCHULTZ: Yes.
20 MR. LEHMAN: -- verify that the behavior 21 is similar to the University of Texas.
22 MR. SCHULTZ: And that could, in fact, 23 require an additional research program, as well as site 24 characterization and evaluations?
25 MR. LEHMAN: Well, I think --
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222 1 MR. SCHULTZ: What -- I'm trying to get a 2 picture of what you are expecting out of that license 3 condition.
4 MR. LEHMAN: Sure. There's, I mean, 5 there's a lot done in the condition, but it's 6 confirmatory in nature.
7 So, the expectation, based on the 8 representativeness of the testing, is that it will match 9 the behavior. But this is just to confirm, when they 10 have more data from the onsite structures, the behavior 11 is the same and that the correlation is matching with 12 what's happening at Seabrook.
13 So, the expectation is that it will, but 14 this is corroboration with onsite --
15 MR. SCHULTZ: Okay. Is the condition --
16 all I see in the condition is a statement that this 17 is going to be done.
18 But is there enough documentation about 19 the expectation so that six years from now, the NRC 20 and NextEra can determine what needs to be done? They 21 may not be the same people as are here in this room 22 today.
23 MR. LEHMAN: Yes, that's a great point.
24 And the -- you're right, the license condition is fairly 25 high level and just says, this will be done.
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223 1 But it has reference to documents that 2 they've submitted on the docket that were reviewed, 3 which had very specific explanations of how it will 4 be done. So --
5 MR. SCHULTZ: Okay.
6 MR. LEHMAN: -- yes, that detail is there.
7 MEMBER BALLINGER: And it's my 8 understanding that there's AMPs that are in place for 9 this, that are independent of any of this, that will 10 ensure that they'll -- if they adhere to the AMPs, 11 they'll keep track of it.
12 MR. LEHMAN: Yes. Angie will talk about 13 the management programs a little bit later. But, I 14 mean, this program is in place now and it will go into 15 license renewal as the Aging Management Program and 16 we'll be tracking all of this stuff.
17 This was just to capture that confirmation 18 piece, to make sure that the behavior aspect is the 19 same from the test program to Seabrook. But, yes --
20 CHAIRMAN SKILLMAN: That was --
21 MR. LEHMAN: -- the AMPs are in place as 22 well.
23 CHAIRMAN SKILLMAN: That was the concluding 24 slide from the last presentation. So, I feel 25 comfortable that --
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224 1 MR. SCHULTZ: Thank you.
2 CHAIRMAN SKILLMAN: -- the actions going 3 forward are clearly codified for whatever that next 4 generation may be, that will have the accountability 5 to execute this.
6 MR. SCHULTZ: Sounds good, thank you.
7 MS. BUFORD: And I was just going to add 8 that the expectation from carrying out the license 9 condition is that the NRC, in its continued oversight 10 of Seabrook, if the results are different than expected, 11 then there would be -- we would expect NRC engagement 12 and Regional oversight activities, how they saw fit, 13 to address a deviation from what they thought to that 14 corroboration piece. So, that's where we would address 15 it.
16 MR. LEHMAN: All right, if we can go to the 17 next slide, that talks about the license condition as 18 well, too.
19 So, the NRC staff is requiring a license 20 condition to confirm that future expansion behavior 21 of ASR-affected Seabrook structures aligns with the 22 large-scale testing program specimens.
23 The first portion of the license condition 24 requires an assessment of overall Seabrook expansion 25 behavior, to ensure that it is similar to the behavior NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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225 1 seen during the testing program, while the second 2 portion of the license condition requires the use of 3 potential future Seabrook expansion data to confirm 4 that the modulus expansion correlation can accurately 5 predict expansion. Next slide, please, George.
6 In addition to the NRR staff review, the 7 Division of Engineering and the NRC Office of Nuclear 8 Regulatory Research provided an independent peer review 9 of the test program development and conclusions and 10 the results of their independent review supported the 11 conclusions reached by the NRR reviewers.
12 So, staff conclusion on the review of the 13 LSTP. Based on its review of the testing program and 14 the representativeness of the program, the staff finds 15 that it is reasonable to apply the results of the testing 16 program to Seabrook structures and to use the original 17 design equations, as long as Seabrook expansion 18 behavior remains similar to the specimens and expansion 19 remains below the tested limits.
20 Unless there is further questions, I'll 21 now turn the presentation back to Nik to discuss the 22 Regional oversight of the large-scale testing program.
23 MR. FLOYD: Thanks, Bryce. The NRC 24 completed a total of six weeks of inspection at the 25 Ferguson Structural Engineering Laboratory at the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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226 1 University of Texas. This also included one week of 2 a joint inspection audit with the licensing reviewers.
3 As Bryce stated before, the testing was 4 initiated to help resolve the open operability 5 determinations related to ASR at Seabrook.
6 As part of the CAL inspections, that's 7 confirmatory action letter inspections, in 2012 and 8 2013, the NRC verified that the overall testing program 9 approach was sufficient developed and described to 10 support an understanding of the testing plans and 11 objectives.
12 Our inspections and observations of the 13 testing program allowed for insights into the Seabrook 14 Structures Monitoring Program, the operability 15 determinations, and enhancements to existing Aging 16 Management Programs.
17 The inspectors communicated these results 18 during periodic Seabrook ASR Issue Technical Team 19 meetings and it was this feedback from the inspectors 20 to Headquarters staff, that assisted in their technical 21 review efforts. Next slide, please.
22 One of the significant observations 23 identified during the testing program, and also seen 24 during our inspections, was the extent of through-wall 25 expansion examples versus the in-plane expansion.
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227 1 As a result, NextEra updated its testing 2 program to evaluate the best instrument for measuring 3 through-wall expansion, as you heard earlier.
4 The inspectors discussed this testing plan 5 and reviewed the results of the instrument selection 6 study with NextEra staff to verify the reliability of 7 the instrument.
8 NextEra then enhanced their Structures 9 Monitoring Program to include monitoring of 10 through-wall expansion.
11 The inspectors observed the installation 12 of the instruments in the Seabrook walls and during 13 ongoing periodic onsite inspections, we reviewed this 14 inspection data, we also looked for trends and we 15 verified the expansion is within the bounds of the 16 testing program. Next slide.
17 Overall, the inspectors observed proper 18 procedural adherence, good test coordination, and 19 proper communications and safety practices exhibited 20 by the testing staff, the supervisory personnel, and 21 the quality assurance overseers.
22 The inspectors verified proper testing 23 preparations and quality control oversight during each 24 visit to the Structural Lab. And this was really to 25 ensure that such testing met appropriate quality NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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228 1 assurance standards.
2 I will now turn the presentation back to 3 Bryce to discuss the staff's review of the proposed 4 Methodology Document.
5 MR. LEHMAN: All right, thanks, Nik. I'm 6 going to discuss the methodology now. A lot of the 7 details on methodology, obviously, have already been 8 covered, so I'm going to try to focus on the staff's 9 review and the associated findings. Next slide. Go 10 back just one.
11 Just a high level of what was in there, 12 as discussed previously, they submitted an LAR to 13 account for the ASR. And the license amendment request 14 proposed a unique three-stage analysis methodology to 15 address the ASR load and associated building 16 deformations.
17 The proposed methodology includes five 18 supplements to the Seabrook design code of record and 19 a detailed description of how to implement the 20 methodology is captured in the Methodology Document.
21 Which I think gets to some of the stuff 22 we were just discussing, the detail of how to do it 23 as they move forward.
24 MEMBER MARCH-LEUBA: Sorry to ask, 25 procedurally, is this an attachment to the LAR? This NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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229 1 Methodology Document?
2 I'm thinking, are you issuing and SER to 3 approve it? Or are you, by approving the LAR, you are 4 implicitly improving the methodology? How are we 5 handling the approval?
6 MR. LEHMAN: Well, it was submitted as 7 support of the LAR and it's referenced in, and we'll 8 get to it a little bit later, but it's referenced in 9 the updated FSAR, with the revision number on there.
10 MEMBER MARCH-LEUBA: Well, if you guys are 11 happy, I'm happy. It's not an issue.
12 MR. LEHMAN: Okay. So, the staff review 13 of the methodology was supported by Brookhaven National 14 Laboratory and included two site audits to review the 15 implementation of the methodology, as well as multiple 16 rounds of request for additional information.
17 The review of the methodology focused on 18 the five areas shown on the slide, and I'll discuss 19 each of these in turn. All right. Next slide, please.
20 The first step in the evaluation 21 methodology is determining the ASR load. Depending 22 on the stage of the analysis, the ASR load is either 23 estimated using concrete strain based on in-plane 24 expansion or a finite element model is developed for 25 the structure.
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230 1 In situ loads are applied to the model and 2 the ASR loads and concrete backfill loads due to ASR 3 are adjusted until the model deformations match those 4 measured in the field.
5 The staff reviewed the process for 6 developing the ASR load and finds it reasonable. The 7 Methodology Document clearly defines how the ASR load 8 and concrete backfill load can be adjusted within the 9 model and provides guidance on how it is determined 10 that the model aligns with the field measurements.
11 In addition, the staff audited multiple 12 calculations in each analysis stage and verified that 13 the licensee was estimating the load consistently and 14 in accordance with the guidance in the Methodology 15 Document.
16 MEMBER KIRCHNER: Let me ask here, did you 17 ask the applicant team about qualification of the finite 18 element code for this application?
19 Did you look at that at all in -- I know 20 it's a widely available code, but for this application, 21 did you look at how they actually modeled the 22 structures, the aggregate and the reinforcement, et 23 cetera, in the concrete, in the finite element code 24 in their methodology?
25 MR. LEHMAN: Yes, we did look at that.
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231 1 George, can you expand on that at all?
2 MR. THOMAS: Yes. During the audit, the 3 staff did look at sample calculations to verify 4 implementation of the methodology, including the 5 application of the computer code.
6 MEMBER KIRCHNER: Well, I don't doubt that 7 the applicant knows how to use a finite element code, 8 my question is perhaps a little more nuanced.
9 Is the actual modeling of the structure 10 and the impact of ASR within the finite element code?
11 I mean, is the nodalization sufficient to capture that?
12 I'm not -- I don't find application of a 13 code like that to a large structure showing reasonable 14 agreement as a means for qualifying the code for the 15 task at hand.
16 Usually you would take elements of the 17 large-scale test program, where they actually bent --
18 they put loads on beams and check and make sure that 19 the finite element code could reproduce the results 20 of those test. Was anything like that done or checked?
21 MR. THOMAS: The way the load was applied 22 was the in-plane strain was applied as a thermal strain 23 within the ANSYS computer model.
24 MEMBER KIRCHNER: Well, it seems to me it's 25 a rather straightforward application of the -- it's NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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232 1 ANSYS, isn't it? -- of the code here to model some of 2 the tests that were conducted in Texas to just make 3 sure that the code can reproduce the measured 4 deformation and stresses that they saw on the test, 5 with these large elements. It's good benchmark 6 material.
7 I'm hearing that wasn't done, is what I'm 8 -- I would think someone in Research would suggest that.
9 We typically do that with other codes, when 10 we apply them to systems analysis, do separate effects 11 tests, at least, to make sure that we understand how 12 nodalization and correlation assumptions impact the 13 results.
14 MR. THOMAS: Yes. Let --
15 MEMBER KIRCHNER: I guess that's not a 16 question now, it's a comment.
17 MR. THOMAS: Yes. Well, the way the code 18 was used here was in a simple linear elastic analysis, 19 which is a standard analysis. They didn't go further 20 into the nonlinear aspects.
21 MEMBER KIRCHNER: I didn't ask whether you 22 went beyond cracking, but up until that threshold, it 23 would be a useful way to benchmark the application of 24 the code to these structures.
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233 1 from Research who --
2 MR. PIRES: Yes, good afternoon. My name 3 is Jose Pires, I'm from the Office of Research. My 4 understanding is that these analyses are not limit state 5 analyses.
6 These are linear analyses, design-basis 7 calculations. So, this code has been qualified for 8 this purpose. It is used frequently to analyze 9 reinforced concrete structures for design 10 calculations.
11 The tests, the testing program went way 12 past the design limits. They are ultimate capacity 13 tests to see if the stress equations in the ACI are 14 applicable. So, they went way past the regime in which 15 the code was used for. The code --
16 MEMBER KIRCHNER: I understand that.
17 MR. PIRES: -- the calculations of the code 18 didn't go to that level of deformation and response, 19 are way below that. So, that's -- and the code has 20 been qualified for that purpose, because it's used 21 extensively for design analysis for applications.
22 MEMBER KIRCHNER: I understand all that.
23 What I'm asking you is, you're studying the effect of 24 ASR on the performance of these structures.
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234 1 that there was no -- I'm interested in how you put in 2 the material properties to the code and how you 3 nodalized that model to take into account the variation 4 in ASR, because you had samples of various levels of 5 ASR degradation.
6 MEMBER BALLINGER: In particular, the 7 modulus? That's really what would be affected.
8 MR. PIRES: Right.
9 MEMBER RICCARDELLA: Well, I mean, there 10 were some modeling assumptions that were made. You 11 used shell elements for the shell, you used membrane 12 elements for the rebar.
13 These are modeling assumptions that could 14 have been -- that could be tested in the -- against, 15 say, one of the beam test programs, to show that you're 16 calculating the proper stresses in the rebar, up to 17 cracking, or things of that sort. I think that's what 18 Walt is getting to.
19 DR. BAYRAK: Certainly, this is -- once 20 again, this is Ozzie Bayrak. Such validations are 21 always useful, but just to go back to the point that 22 the analyses conducted are linear elastic, using ANSYS.
23 And if you recall one of the slides I 24 showed, on our rebar anchorage test programs, where 25 we're looking into actually a family of curves, we NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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235 1 looked into the first part, control specimen versus 2 ASR-affected, where the stiffness does not change 3 appreciably.
4 So, that is the range in which you would 5 be doing this validation. And ANSYS, I've used it a 6 number of times, not in the recent past, but in terms 7 of analyzing a typical reinforced concrete beam 8 behavior, it does that just fine.
9 I would be surprised if such an analysis 10 showed that, particularly within that range, the 11 behavior cannot be captured.
12 Now, later on in the game, when you have 13 flexural cracking, yielding, and so on and so forth, 14 such nonlinear actions, can you pick that up with ANSYS?
15 My answer to that would be, I have no idea. But for 16 the linear elastic portion, I'm fairly confident.
17 MEMBER KIRCHNER: Okay.
18 DR. BAYRAK: I think that's --
19 MEMBER KIRCHNER: All right, thank you.
20 DR. BAYRAK: -- what you were trying to 21 indicate.
22 MR. PIRES: The intent of the testing 23 program, the methodology and so forth, was that you 24 could do that. That you could map the problem into 25 the design analysis situation. So, that was the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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236 1 purpose.
2 CHAIRMAN SKILLMAN: Let's keep on going.
3 MR. LEHMAN: All right. I think we're on 4 the next slide, George. And that's all, so I think 5 we understood the comment. Are there any other 6 questions on that? All right, moving on.
7 MEMBER RICCARDELLA: Did the staff do any 8 independent calculations?
9 MR. LEHMAN: No, we did not. But I think 10 we understood the comment and we'll look at it more.
11 The next topic is the development of ASR 12 load factors. So, next slide, please. There, 13 perfect.
14 To incorporate the ASR load into the 15 existing load combinations, it was necessary to develop 16 load factors for the ASR load. The factors for ASR 17 were developed based on the reliability index approach 18 used to develop probabilistic-based load factors in 19 ACI 318 and ASE 7.
20 The staff finds this approach reasonable, 21 because it follows the same method used in industry 22 consensus standards and the developed factors maintain 23 the original reliability of the design-basis load 24 combination.
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237 1 incorporated into the updated Final Safety Analysis 2 Report. Next slide, please.
3 The original license amendment request 4 included multiple analysis methods that appeared to 5 be departures from the codes of record. In response 6 to staff requests for additional information and 7 discussions during site audits, NextEra identified five 8 supplements to the existing codes of record.
9 Supplement 1 was identified as the 10 incorporation of ASR loads into the existing FSAR 11 design-basis load combinations. The staff finds this 12 supplement acceptable, because it officially 13 incorporates ASR loads into the design basis.
14 Supplement 2 was identified as the use of 15 the original design code equations to determine the 16 strength of ASR-affected concrete sections. As 17 discussed previously, the staff finds this supplement 18 acceptable, based on the results of the large-scale 19 testing program. Next slide, please.
20 Supplement 3 was identified as using the 21 procedures defined in ACI 318-83, Section 11.7, to 22 calculate shear friction capacity for members subjected 23 to net compression.
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238 1 Section 11.7 of ACI 349-97, which is endorsed by the 2 staff in Reg Guide 1.142. Next slide, please.
3 The staff reviewed Supplements 4and 5 4 together, because both supplements relate to crack 5 section properties. Supplement 4 deals with flexural 6 crack section properties, while Supplement 5 addresses 7 axial and shear stiffness of structural components.
8 The staff noted that the approach was 9 reasonable for normal concrete, but did not appear to 10 account for the test results, which indicated a relative 11 increase in stiffness with ASR due to the ASR 12 pre-stressing effect.
13 The staff discussed this issue with NextEra 14 during an audit and issued an RAI. In response to the 15 RAI, NextEra revised the referenced equations and the 16 guidance in the Methodology Document to account for 17 the observed increases in stiffness.
18 The Methodology Document clarifies the 19 tensile and shear crack initiations are based on net 20 concrete strength after the ASR pre-stressing effects 21 are overcome.
22 The staff finds this approach acceptable, 23 because it is consistent with industry standards for 24 developing crack section properties and the revised 25 guidance in the Methodology Document ensures the ASR NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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239 1 pre-stressing effects are taken into account in the 2 analysis.
3 The next main topic of review is the 4 threshold factor and threshold limits. These are 5 structure-specific outputs of the methodology that 6 quantify the remaining margin in each structure.
7 The staff finds the use of the threshold 8 factors and threshold limits acceptable, because the 9 calculations used to develop the values follow the 10 design code of record with acceptable supplements as 11 just discussed.
12 The threshold factor allows for future ASR 13 expansion and quantifies the remaining margin in each 14 structure.
15 If an acceptable factor cannot be developed 16 or if a threshold limit is reached, a more detailed 17 analysis stage may be entered or a structural 18 modification may be developed to reestablish the 19 margin. Next slide, please.
20 The last major topic reviewed by the staff 21 as part of the methodology relates to reinforcement 22 stresses and strains.
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240 1 conditions.
2 However, unlike other service loads, ASR 3 expansion is a self-straining load whose progression 4 has a potential for straining reinforcement beyond 5 yield under service conditions.
6 To address this, NextEra identified 7 additional actions that will be taken if the in-plane 8 ASR strain exceeds two millimeters per meter over a 9 large region, which is the approximate level at which 10 rebar could yield, based on minimum specified yield 11 strength.
12 If this limit is exceeded, the Methodology 13 Document recommends further evaluation of the area, 14 which could result in a retrofit or repair to mitigate 15 possible reinforcement yield or slippage, or could 16 result in further analysis to qualify the structure.
17 MEMBER MARCH-LEUBA: I know it's late, but 18 remind me again -- maybe I should ask the boss. On 19 the CRs, we put limitations and conditions.
20 On LAR approvals, we don't add limitations, 21 right? So, we either approve what the licensee 22 proposes as these limits or we reject it, is that the 23 case?
24 MR. DONOGHUE: In this case, we're approving 25 with license conditions. So, they have to satisfy NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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241 1 those license conditions as part of their license now.
2 MEMBER MARCH-LEUBA: So, we can add --
3 MR. DONOGHUE: Once it's approved.
4 MEMBER MARCH-LEUBA: -- a license condition 5 on the LAR? You can add a condition to the LAR?
6 MR. DONOGHUE: Yes. Now --
7 MEMBER MARCH-LEUBA: Okay.
8 MR. DONOGHUE: -- there's some particulars 9 about that and we had to work with the licensee to make 10 sure that it's something that's confirmatory.
11 It's not going to be new analyses or 12 information that are given to us to review, it's 13 something that can be confirmed by inspection, 14 basically.
15 MEMBER MARCH-LEUBA: So, there is a process 16 to get that? I was thinking --
17 MR. DONOGHUE: Yes.
18 MEMBER MARCH-LEUBA: -- because we run into 19 that problem with the design certifications.
20 MR. DONOGHUE: Right. So, this gets --
21 MEMBER MARCH-LEUBA: And I'm --
22 MR. DONOGHUE: I'm sorry. This gets back 23 to an earlier question about, if it's not spelled out 24 in the condition, where is it?
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242 1 aging programs and the documentation they have to follow 2 and our oversight, I think Angie mentioned this, our 3 oversight is going to confirm that they live up to their 4 programs. And we do this in all areas throughout the 5 plant, besides just monitoring ASR.
6 MEMBER MARCH-LEUBA: In opening my mouth, 7 I think I answered my question myself --
8 MR. DONOGHUE: Okay.
9 MEMBER MARCH-LEUBA: -- you need an SER if 10 you're modifying Tech Specs.
11 MR. DONOGHUE: Right.
12 MEMBER MARCH-LEUBA: But because this 13 doesn't modify Tech Specs, what they have done is a 14 regulatory commitment.
15 MR. DONOGHUE: Well, no, it's a license 16 condition and they are modifying their license, because 17 now, this program is going to be part of their -- it's 18 going to be put in their UFSAR. And they --
19 MEMBER MARCH-LEUBA: And there is --
20 MR. DONOGHUE: -- we needed that -- so, the 21 reason these are coupled to the license renewal is they 22 needed to get this into their current licensing basis 23 to get the license renewal submitted.
24 MEMBER MARCH-LEUBA: And there is no doubt 25 in my mind that they will follow the proper methodology.
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243 1 MR. OESTERLE: Yes, so, just let me add 2 something. The -- earlier in the discussion today --
3 oh, sorry, Eric Oesterle, DMLR.
4 Earlier in the discussion today, there was 5 mention that the staff had a difference of opinion with 6 NextEra in that, because this was a new method of 7 evaluation, it needed to be incorporated into the UFSAR 8 and the process to do that is via a license amendment.
9 So, if you look at the criteria in 50.59, 10 there's a question in there about a new method of 11 evaluation. And so, that tripped a criteria, which 12 requires a license amendment to include it in the FSAR.
13 MR. LEHMAN: But just to clarify, this limit 14 is not part of the license condition. This is not 15 captured in the license condition, this is captured 16 clearly in the Methodology Document, which is 17 referenced in their FSAR update. So, we would still 18 have oversight of it, but it's not part of the license 19 condition.
20 So, the staff finds this approach 21 acceptable, because a reasonable limit for in-plane 22 ASR strain has been identified and if the limit is 23 exceeded, further evaluation will be performed, 24 including the evaluation of potential rebar slip or 25 yield under service conditions. Next slide, please.
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244 1 This is sort of the overall summary. The 2 staff reviewed the methodology and based on its review, 3 the staff finds that NextEra's evaluation method is 4 a reasonable approach for analyzing structures with 5 ASR, because the approach is consistent with Seabrook's 6 code of record design philosophy.
7 NextEra provided acceptable justification 8 for the continued applicability of the code, along with 9 the five proposed supplements to the code.
10 NextEra's approach for estimating the load 11 due to ASR is reasonable and based on field data, and 12 the load is incorporated into the existing load 13 combinations with reasonable load factors.
14 The methodology quantifies the future ASR 15 expansion that can be accommodated by a structure and 16 identifies quantitative acceptance criteria for 17 threshold parameters for each structure.
18 Additionally, limits are in place to ensure 19 structures are evaluated for potential rebar yield 20 under service loads and monitoring programs are in place 21 to ensure ASR expansion remains within the identified 22 test program limits and structure-specific threshold 23 limits.
24 Angie will discuss the monitoring programs 25 in more detail in the upcoming slides.
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245 1 Finally, confirmatory actions in the 2 license condition provide assurance that the 3 large-scale testing program results will continue to 4 be applicable to Seabrook structures. Next slide, 5 please.
6 The staff also finds that NextEra's 7 evaluation methodology is adequately captured in the 8 Methodology Document and the proposed UFSAR update.
9 The staff audited multiple calculations 10 in each analysis stage and determined the Methodology 11 Document is robust and detailed enough to be repeatable 12 for any structure or analysis stage.
13 The Methodology Document will provide 14 appropriate monitoring parameters and associated 15 acceptance criteria for each analyzed structure.
16 The UFSAR update captures the five code 17 supplements and references the Methodology Document.
18 The UFSAR also includes the ASR load and the updated 19 load combinations and identifies the expansion limits.
20 Based on its review, the staff finds that 21 the proposed methodology is adequately described in 22 the proposed UFSAR update and provides reasonable 23 assurance that ASR-affected structures will continue 24 to meet the design codes as supplemented.
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246 1 evaluation methodology and I will turn the presentation 2 over to Angie to discuss ASR monitoring and 3 plant-specific AMPs.
4 MS. BUFORD: Okay. Thanks, Bryce. So, the 5 applicant has proposed and is implementing monitoring 6 programs that rely on the robust methodology that the 7 licensee is crediting in their license amendment 8 request and their plan is to monitor ASR-related 9 behaviors under two plant-specific programs.
10 The staff reviewed the programs against 11 the plant-specific review guidelines, per the 12 ten-element review process outlined in the Standard 13 Review Plan for License Renewal.
14 We thought that appropriate, considering 15 that the programs that are being implemented today are 16 the programs that are planned for the period of extended 17 operation.
18 This next slide has been covered, it's just 19 a high level overview of the ASR monitoring plan. So, 20 for time, we'll just move to the next slide.
21 MEMBER KIRCHNER: Sorry to slow you down.
22 MS. BUFORD: Sure, no problem.
23 MEMBER KIRCHNER: I have a question about 24 methodology for the building deformation. Is there 25 any plan to estimate gross movement of individual NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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247 1 buildings because of pressure from the backfill 2 expansion and what's the consequence of that?
3 Is there any limits to -- hypothetically, 4 just say there's a gap there for seismic purposes and 5 it's closing because of expansion and pressure. Is 6 there any program in place that defines an acceptable 7 methodology for estimating that and predicting it going 8 forward?
9 Or is it going to be a reactive monitor 10 what the gap is and, at some point, if it closes and 11 creates a seismic or other induced load, then you 12 mitigate that or calculate your way out of it or 13 whatever?
14 I mean, is that the response to this issue 15 of building deformation that's because the structures 16 float and are being pushed, if you will, and stressed 17 by the backfill expanding?
18 MS. BUFORD: Yes. So, our review process 19 for their -- the licensee actually has a specific 20 program called the Building Deformation Monitoring 21 Program that --
22 MEMBER KIRCHNER: Right, I saw that coming 23 up.
24 MS. BUFORD: Yes, so that is coming --
25 MEMBER KIRCHNER: Right.
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248 1 MS. BUFORD: -- up, but that's what you're 2 referring to. And so, what that program does is that 3 it looks at all of the different -- for each structure, 4 it looks at the different parameters that are unique 5 to that structure that are related to both ASR and any 6 movement, large cracks, and any ASR-related or building 7 deformation aging effects.
8 And our guidance says that, when we review 9 this, we need to see that indications are both trended 10 and also there's a forward look in the review to say 11 that the licensee needs to show that, based on prior 12 trending, that they will not reach their threshold 13 limits for any of the monitored parameters before the 14 next inspection time.
15 And we've heard today that there's 16 actually, even though it's not part of the guidance 17 for license renewal, NextEra actually has a limit that's 18 what they were calling their administrative limit, 19 that's actually even before they would get -- so, that's 20 actually the limit they use, which has a conservatism 21 even built into that.
22 That's actually what they're trending to, 23 so the program trends up to the next inspection, based 24 on previous movement. And like we said, it's slow and 25 they have years' worth of data that they can use to NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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249 1 trend.
2 And every structure is different, so there 3 is essentially a Building Deformation Monitoring 4 Program for every structure. Does that --
5 MEMBER KIRCHNER: Okay.
6 MS. BUFORD: -- answer your question?
7 MEMBER KIRCHNER: Kind of, sort of, yes.
8 MR. LEHMAN: I can expand on that.
9 MEMBER KIRCHNER: It's a little different, 10 I guess, this problem or issue or -- than the actual 11 reinforced concrete structures, which they bounded with 12 their large-scale test program.
13 And now, you're working within a defined 14 envelope or limits to make sure you don't exceed what 15 was tested.
16 I don't expect a test program for bulk 17 deformation or large-scale movement of buildings, but 18 I was just curious how you project out through the life 19 of the license and the renewal application.
20 MS. BUFORD: So, the test program is not 21 -- it was not directly related to the --
22 MEMBER KIRCHNER: No, I --
23 MS. BUFORD: -- building deformation, but 24 --
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250 1 quite different.
2 MS. BUFORD: So, actually, the inputs from 3 the test program specific to the actual ASR expansion, 4 that's the ASR monitoring program, which it's actually 5 the other program.
6 MEMBER KIRCHNER: Okay.
7 MS. BUFORD: So, the ASR monitoring program 8 is specifically looking at the in-plane cracking and 9 the through-wall cracking and directly comparing to 10 those testing limits.
11 MEMBER KIRCHNER: I understand that 12 completely.
13 MS. BUFORD: The Building Deformation 14 Monitoring Program takes -- weaves conclusions from 15 the testing program into the calculation that governs 16 the extent of aging effects for the -- so, it basically 17 wove into the calculation.
18 And it's not -- the testing program isn't 19 being in any way tied directly --
20 MEMBER KIRCHNER: No, I understood all that.
21 No, I'm -- I guess, indirectly, what I'm asking is, 22 is there an effort underway to estimate what bulk 23 deformation would occur through the license renewal 24 application time period?
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251 1 -- in our programmatic review, we look to understand 2 that there are mechanisms in place to -- and I think 3 that Michael Collins alluded to this previously in the 4 presentation, where we're not looking for them to 5 estimate out the, either the expansion or the bulk 6 deformation through any time period except to the next 7 inspection. And that the monitoring criteria will 8 identify deficiencies prior to that.
9 But there's no -- it's our understand and 10 it's acceptable to the staff that there is not a 11 projection out to any extended time period, because 12 --
13 MEMBER KIRCHNER: To the 26-year or whatever 14 --
15 MS. BUFORD: -- it's a condition monitoring 16 program.
17 MEMBER KIRCHNER: -- the time frame is.
18 MS. BUFORD: Yes. So, if at any point --
19 MEMBER KIRCHNER: So, it's a more reactive, 20 monitor and react approach, rather than to bound the 21 problem, like you did with the large-scale test program?
22 MS. BUFORD: We'd call it more condition 23 monitoring, because --
24 MEMBER KIRCHNER: Okay.
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252 1 conditions up to a point at which you need to go into 2 your Corrective Action Program and look into 3 operability of structures. And that's based on the 4 work that was done.
5 But the -- programmatically, the NRC looks 6 to make sure that the programs can effectively identify 7 any of the aging effects associated with the structure 8 prior to the next scheduled inspection.
9 MEMBER KIRCHNER: Well, typically, when we 10 have an issue surface like this, I would hope that 11 Research would be involved and they would be thinking 12 through, okay, what's the implication of this?
13 I'll bring up some analogies, I guess, at 14 some risk, like reactor vessel degradation, because 15 of neutron irradiation.
16 What you do is estimate out to the lifetime 17 of the reactor vessel what the fluence is and what the 18 effect is on the structural capacity of the reactor 19 vessel.
20 Here, it's a little bit different, because 21 we're talking about bulk movement, but I would think 22 that one would want to take a stab at estimating how 23 these islands are floating and being moved, to see 24 whether or not you would then, in the lifetime of the 25 plant, have a condition occur where you have, let me NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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253 1 say, building to building contact that's unacceptable 2 because of the loads it would induce, et cetera.
3 So, I'm just curious if any work is underway 4 to look at that aspect of the problem, or are you just 5 going to monitor --
6 MS. BUFORD: So, we don't have --
7 MEMBER KIRCHNER: -- and react?
8 MS. BUFORD: -- any work underway to do that, 9 and that's -- there is a specific reason for that, 10 because those types of analyses are, under the 11 regulations, are time-limited aging analyses.
12 And those are the analyses that look out 13 to the end of life of the plant and either bound the 14 behavior or propose Aging Management activities.
15 One of the criteria for a time-limited 16 aging analysis that looks out to the end of plant life 17 is that there is an analysis that's already in the 18 licensing basis that's associated with time, where it 19 was assumed that there would be a 40-year license and 20 then, licensees, applicants, have to revisit that 21 40-year analysis out to the extended period.
22 In this case, there's not a licensing basis 23 calculation associated with --
24 MEMBER KIRCHNER: I understand, because --
25 MS. BUFORD: -- the life of the plant --
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254 1 MEMBER KIRCHNER: -- you discovered this 2 in 2014.
3 MS. BUFORD: Well, right. But in terms of 4 our -- it's acceptable and adequate for this to be a 5 condition monitoring program, so long as aging effects 6 can be identified --
7 MEMBER KIRCHNER: Okay, fair enough.
8 MS. BUFORD: -- prior to the next 9 inspection.
10 MEMBER KIRCHNER: That's fair enough.
11 Thank you.
12 MR. COLLINS: So, the issue of the backfill 13 concrete, those loads are being applied by SG&H, as 14 far as in their buildings analysis.
15 And we have our threshold limits and those 16 threshold limits drive the inspection criteria, whether 17 it be a seismic gap, whether it be a distances between 18 fire gaps. So, we're not expecting a massive blowout 19 of a wall, so we are --
20 MEMBER KIRCHNER: No, I wasn't --
21 MR. COLLINS: No, and I --
22 MEMBER KIRCHNER: -- suggesting that.
23 MR. COLLINS: -- know you weren't. But I 24 think we got a little dysfunction there with regards 25 to the backfill concrete. That is being monitored, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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255 1 that input of that backfill concrete is being input 2 into our analysis of --
3 MEMBER KIRCHNER: Okay, fair enough.
4 MR. COLLINS: -- the structures.
5 MEMBER RICCARDELLA: Could I just make sure 6 my understanding is correct? You've done the 7 structural models of each of the structures, certainly 8 the ones that fall into the Stage Three.
9 And my understanding is that the Building 10 Deformation Monitoring Program is just there to confirm 11 the predictions of those structural models. So, that 12 it has been modeled, by including the factor, I forget, 13 the threshold factor in there, that does take it to 14 the end of life.
15 If you go in there and measure something 16 that says, well, I'm right up to the threshold, to that 17 threshold factor, you basically have to take an action.
18 MR. COLLINS: That's correct.
19 MEMBER RICCARDELLA: Right?
20 MR. COLLINS: Yes. And I'm Michael 21 Collins, Director of Engineering, Seabrook Station.
22 MEMBER RICCARDELLA: Yes. I mean, that 23 might not be so true for the ones that are maybe a Stage 24 One or a Stage Two, but certainly for anything that 25 was Stage Three, you've got a finite element model NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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256 1 predicting deformations and your monitoring program, 2 as I understand it, is just to confirm those 3 measurements, right?
4 MR. COLLINS: That's well said.
5 MEMBER RICCARDELLA: Okay, thank you.
6 MR. LEHMAN: And also, for all of the stages, 7 that limit is a limit they have to take action at.
8 But at a Stage One, it might just be, go to a Stage 9 Two, or go to a Stage Three. At a Stage Three, it's 10 a little bit more and the action might be a mod at that 11 point.
12 MEMBER RICCARDELLA: Understood.
13 MR. THOMAS: This is George Thomas. Just 14 to add to that, even if it's a Stage One analysis, if 15 the field observations indicate that the seismic gap 16 is an important parameter, that would be identified 17 as the threshold parameter and monitored. So, it's 18 all field data driven.
19 CHAIRMAN SKILLMAN: Let's proceed, please.
20 MS. BUFORD: Okay. So, we were going to 21 move to the next slide. We were trying to skip that 22 slide and so, we are going to still. So, I'm going 23 to go back, I know we talked a little bit about the 24 building deformation monitoring, but that's coming in 25 a couple slides.
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257 1 The ASR monitoring program, the staff 2 reviewed the ASR monitoring program using the 3 ten-element review guidance that I mentioned in the 4 Standard Review Plan for License Renewal.
5 And we noted that visual inspections are 6 performed. And for any concrete onsite, that's a 7 five-year basis. That's the baseline. And the 8 frequency for the baseline inspections is adequate --
9 and actually, I won't call them baseline, but I'll call 10 them routine structures monitoring inspections.
11 That frequency is adequate because, 12 firstly, NextEra has already performed a comprehensive 13 baseline inspection on all concrete at Seabrook. Any 14 area with visual indications of ASR were noted in that 15 baseline inspection. The five-year inspection is for 16 concrete where ASR has not been previously identified.
17 The staff agrees that five years is 18 sufficient to be able to both detect initial signs of 19 ASR, since ASR is a slow progressive phenomenon, and 20 has confidence that it would be unlikely for that area 21 to progress from having no signs of ASR to having ASR 22 damage that could challenge the intended function.
23 The inspection frequencies for all 24 locations that have any indication of ASR are 30 months 25 and move to six months, according to ASR severity.
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258 1 The program uses combined cracking index, 2 which you've heard extensively today, to measure 3 in-plane cracking for areas whose CCI measures less 4 than one millimeter per meter.
5 The staff agrees that CCI is a valid method 6 of measuring ASR micro-cracking, because it was -- well, 7 one, it is the standard for -- it's noted in the Federal 8 Highway Administration literature. And also, just 9 because it was found by the large-scale testing program 10 to correlate well to concrete strain.
11 And also, the one millimeter per meter 12 threshold for more frequent inspections is very 13 conservative, because it represents a low level of 14 strain.
15 For these low ASR severity levels, the 16 30-month frequency associated is conservative based 17 on the slow rate of ASR progression.
18 This has also been validated with data from 19 Seabrook structures and the staff has confidence that 20 for a low ASR severity, a 30-month inspection interval 21 will identify degradation and trend to the next 22 inspection prior to a loss of intended function.
23 Through-wall expansion is measured in any 24 structure whose CCI exceeds one millimeter per meter.
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259 1 through-wall expansion exceeded in-plane expansion for 2 structures with more severe ASR degradation.
3 One millimeter per meter expansion is a 4 low and conservative factor for through-wall 5 extensometer installation.
6 The through-wall expansions are measured 7 every six months for every location that uses an 8 extensometer and the expansion limits are based on 9 expansion data from the testing program.
10 Since the large-scale testing specimens 11 exceeded their structural acceptability, staff has 12 confidence that as long as the Seabrook structures 13 remain within the tested limits, they will be able to 14 perform their intended functions. Next slide.
15 The staff finds that NextEra's ASR 16 monitoring program is acceptable, because the program 17 begins with visual inspections and progresses to 18 expansion monitoring, as necessary, for increased 19 levels of ASR degradation.
20 The inspection frequencies are 21 conservative and are aligned with guidance in ACI 22 349.3R.
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260 1 environment, which Seabrook concrete is considered to 2 be, since they are susceptible to ASR.
3 The staff has also performed numerous 4 inspections under the reactor oversight process that 5 look at the expansion and deformation behavior and these 6 inspections have concluded that ASR progress has been 7 very slow.
8 In addition, the ASR monitoring program 9 compares total volumetric expansion against reasonable 10 limits from the testing program and license conditions 11 are in place to assess continued assurance that the 12 testing program is valid and representative of 13 Seabrook.
14 In addition, as reflected in the operating 15 experience program element of the program, the program 16 will monitor and evaluate future industry and 17 plant-specific operating experience and the program 18 will be modified if necessary.
19 Any questions on the ASR AMP? Okay. Next 20 slide.
21 So, the other program to manage ASR is the 22 Building Deformation Monitoring AMP. For this AMP, 23 structures with indications of ASR micro-cracking and 24 any other manifestations of ASR are analyzed using the 25 proposed methodology that was discussed earlier.
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261 1 For each structure, analysis defined 2 structure-specific parameters to monitor and has 3 acceptance criteria that is based on an evaluation 4 that's unique to that structure.
5 The program identifies and monitors 6 parameters generated from the Methodology Document and 7 those parameters are quantitative when feasible.
8 Also, the licensee has established a unique 9 program for each structure that references threshold 10 factors that must be met and trended to the next 11 inspection.
12 For each structure, the inspection 13 interval is either three years, 18 months, or six 14 months, based on the stage of analysis, essentially 15 considering the level of conservatism in the 16 calculation or the potential for building deformations 17 to become more severe.
18 The staff believes these frequencies to 19 be adequate in its audit and review of a sample of each 20 stage of analysis and notes that for areas with higher 21 potential to reach the threshold, i.e., the Stage Three 22 analyses, a six-month frequency is very conservative 23 considering the ASR progression is very slow.
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262 1 Program ensures structures continue to meet the code 2 of record, with supplements, if measurements remain 3 below the acceptance criteria. Next slide, please.
4 The staff finds the proposed Building 5 Deformation Monitoring AMP acceptable, because the 6 program identifies appropriate monitoring parameters 7 and acceptance criteria based on the Methodology 8 Document, which the staff has found technically 9 adequate.
10 The Methodology Document has identified 11 the method for monitoring each possible parameter.
12 The staff also finds that the program uses 13 conservative inspection intervals, which are frequent 14 enough to ensure significant changes in deformation 15 are identified and remediation can take place prior 16 to a loss of intended function.
17 The monitoring is based on more and more 18 stringent frequencies based on ASR degradation and the 19 staff has confidence, because we noted from trended 20 data that ASR has progressed slowly.
21 In addition, the inspection frequencies 22 associated with this aging mechanism are closely tied 23 with ACI 349.3R guidance for sites that have operating 24 experience with respect to significant degradation 25 mechanisms.
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263 1 Also, the staff noted that the program 2 includes structural, electrical, and mechanical 3 components in the plant that may be impacted by 4 structural deformations.
5 These components will also be monitored 6 for continued deformation effects and we verified 7 implementation in the licensee's database during our 8 onsite inspection.
9 Finally, the Building Deformation 10 Monitoring AMP will monitor and evaluate future 11 industry and plant-specific operating experience and 12 modify the program as necessary.
13 If there are no questions, I will turn the 14 presentation back to Nik so he can discuss the follow-up 15 license renewal inspection at Seabrook for ASR.
16 MR. FLOYD: Thank you, Angie. Next slide, 17 please. George, next slide. Oh, thank you.
18 The NRC conducted a second license renewal 19 inspection at Seabrook to determine whether actions 20 taken by NextEra since the previous license renewal 21 inspection conducted in 2011 was adequate to manage 22 aging in concrete structures due to the effects of ASR.
23 The inspection was focused solely on ASR, 24 because the 2011 inspection reviewed the other Aging 25 Management Programs.
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264 1 The timing of this inspection was prompted 2 by NextEra's completion of the large-scale testing 3 program, NextEra's submittal of the license amendment 4 request, updates to the Aging Management Programs for 5 the license renewal application, and the NRC completion 6 of staff licensing audits.
7 The inspection involved one Regional 8 Inspector, who was myself, and one Headquarters 9 Inspector, who was Angie, with expertise in both 10 materials and civil engineering.
11 The team was onsite the week of April 30, 12 2018 and the inspection report was issued August 10, 13 2018. Next slide, please.
14 The team reviewed the Aging Management 15 Programs associated with ASR. These were the 16 Structures Monitoring Program, ASR, Building 17 Deformation, and ASME Section 11, Subsection IWL, for 18 containment concrete inspections.
19 The team performed detailed walkdowns on 20 a sample of three structures affected by ASR and 21 verified that the structural deficiencies were being 22 identified, evaluated, and corrected by the applicant.
23 The team did not identify any new deficiencies that 24 were not previously documented.
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265 1 of the Structures Monitoring Program database. This 2 database captures the results of NextEra's monitoring 3 of structures per the Maintenance Rule and also includes 4 the monitoring results from the ASR monitoring and the 5 Building Deformation Monitoring Programs. Next slide.
6 NRC Regional Management provided oversight 7 during this inspection. In the photo, you can see the 8 team on the left and the right, provided their 9 observations and assessments on the Structures 10 Monitoring Program during a walkdown in the Fuel Storage 11 Building.
12 The binder, which you can see in the photo, 13 contained a list of NextEra's documented structural 14 deficiencies, which the inspectors used during their 15 walkdowns to independently verify that all deficiencies 16 were being appropriately identified. Next slide, 17 please.
18 From the walkdown and review of the 19 Structures Monitoring Program database, the team 20 determined that NextEra was implementing the 21 established monitoring programs and was appropriately 22 identifying and correcting issues.
23 The team noted that all in-scope buildings 24 were being monitored in the Structures Monitoring 25 Program for ASR.
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266 1 As part of the new Aging Management 2 Programs, we reviewed ASR-specific monitoring 3 parameters.
4 Those would include combined crack 5 indexing grids, pin-to-pin expansions, extensometers, 6 as well as building deformation monitoring parameters, 7 which would include seismic gap and specified cracking.
8 We determined that these parameters were 9 adequately captured in the program and were being 10 monitored at the program-specified frequencies.
11 NRC inspections of ASR-related issues 12 completed to-date, which would include the semiannual 13 focus inspections, as well as this follow-up license 14 renewal inspection, support the conclusion that there 15 is reasonable assurance that the effects of aging due 16 to ASR in Seabrook structures, systems, and components 17 will be managed through implementation of the programs 18 during the period of extended operation.
19 Also, just a quick note, review of this 20 database, as well as this inspection, did provide us 21 confidence in NextEra staff's ability to implement the 22 program, given its extensive processes for monitoring.
23 As far as just, and this is my personal 24 opinion, as far as benchmarking and Structures 25 Monitoring programs go, this really is probably the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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267 1 most comprehensive Structures Monitoring Program that 2 I've observed. So, I'll just offer that observation.
3 Are there any questions on the scope of 4 the inspection or observations? Thanks very much.
5 I'll turn it back over to Angie.
6 MS. BUFORD: Home stretch. I'm going to 7 now finish the staff's presentation with our 8 conclusions. Next slide, okay.
9 The staff found that there are acceptable 10 plant-specific AMPs provided for both ASR monitoring 11 and building deformation.
12 We found that the existing structures 13 monitoring and ASME Section 11, Subsection IWL AMPs, 14 and structural Aging Management review items have been 15 updated to reflect ASR. And that also includes 16 components that are affected by building deformation.
17 The license renewal safety evaluation 18 report conclusions rely on the large-scale testing 19 program and the license amendment request safety 20 evaluation findings.
21 The SER focuses on monitoring parameters, 22 inspection methods and intervals, acceptance criteria, 23 and evaluation of future operating experience.
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268 1 so that the intended functions will be maintained 2 through the period of extended operation.
3 It's been a long six years and the staff 4 can now conclude that, based on our review, the ASR 5 open item from 2012 is closed.
6 The next slide is just a summary of the 7 regulatory reasonable assurance conclusion.
8 Number one, the applicant demonstrated 9 that proposed plant-specific Aging Management Programs 10 will adequately manage the effects of aging due to ASR, 11 in accordance with the regulations in 10 CFR 54.29(a).
12 The license amendment ensures that 13 programs to evaluate and manage ASR will be added to 14 the current licensing basis.
15 The ongoing Regional oversight and the 16 71002 inspection concluded, from a Regional 17 perspective, that programs are effectively being 18 implemented today and will continue to be effectively 19 implemented through the PEO.
20 And the license conditions that are 21 associated with the license amendment request 22 corroborate future expansion behavior, which will 23 ensure continued applicability of the large-scale 24 testing program to Seabrook structures.
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269 1 presentation and we'd like to welcome your questions.
2 CHAIRMAN SKILLMAN: Angela, thank you very 3 much. Colleagues, any questions for the NRC staff at 4 this point, please? No questions from my colleagues?
5 Let me just do a headcount.
6 Vesna, any comments or anything you would 7 like to communicate at this point, please? Go ahead, 8 Vesna.
9 MEMBER DIMITRIJEVIC: No, I have asked the 10 questions I have been interested in. I think this was 11 a very comprehensive, absolutely wonderful 12 presentation on everybody's contributions.
13 CHAIRMAN SKILLMAN: Okay. Dr. Corradini?
14 MEMBER CORRADINI: No, I agree with Vesna, 15 it was quite comprehensive.
16 CHAIRMAN SKILLMAN: Dr. Rempe?
17 MEMBER REMPE: No, I don't have any 18 additional comments. I do want to thank the staff and 19 all of the folks associated with the Seabrook LAR who 20 presented, because I do think they gave very good, well 21 thought out presentations to elucidate the issue.
22 CHAIRMAN SKILLMAN: Dr. Riccardella?
23 MEMBER RICCARDELLA: I think what I've seen 24 represents a very impressive body of work. I think 25 that the presentations by the licensee and the staff, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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270 1 as well as the documents that we've been provided to 2 review, provide us with adequate information for our 3 deliberations at the main Committee on this topic.
4 CHAIRMAN SKILLMAN: Thank you. Dr.
5 Kirchner?
6 MEMBER KIRCHNER: Just to thank the 7 applicant and the staff, as Pete said, quite thorough 8 and comprehensive.
9 I will reiterate my suggestion from the 10 closed session that as much of the material that we 11 saw today, which I found pretty thorough and complete, 12 that could be made available to the general public, 13 I just would encourage that.
14 CHAIRMAN SKILLMAN: Okay.
15 MEMBER KIRCHNER: I'm referring to 16 materials that were marked proprietary.
17 CHAIRMAN SKILLMAN: Thank you, Walt. Dr.
18 March-Leuba?
19 MEMBER MARCH-LEUBA: Yes, I have a number 20 of comments. First, I'd like to say that, the staff 21 had done a heck of a job. I mean, you really have done 22 a fantastic job. And maybe you don't realize the two 23 things that I think you've done extraordinarily.
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271 1 the plant and going through the procedures and they're 2 supposed to do something in 15 minutes and they did 3 it in 16, aha, we caught you.
4 You guys had an open mind and were asking, 5 what could possibly go wrong?, and identified something 6 that was not -- that you were not looking for. So, 7 that is difficult to do and I congratulate you for doing 8 it.
9 On the Headquarters side, you also did 10 something good, because I wasn't there, but I'm pretty 11 sure the licensee, when confronted with the issue, said, 12 no never mind. Buildings move, sidewalks crack, what 13 are you talking about?
14 And you didn't take no, never mind, for 15 an answer, and pushed it and identified that this has 16 some safety significance and you have taken it to 17 conclusion.
18 And that is difficult to do also, so 19 congratulations. You all should go talk to your bosses 20 and ask for a raise. Not that it's going to happen, 21 but you've done a great job.
22 The licensee has also done a fantastic job.
23 I mean, I'm sure that it took a while to get into the 24 mode of actually responding, but when they did, they've 25 done incredible testing and they have a very good NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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272 1 program with AMPs and with calculations and I have, 2 not being an expert, I have great confidence that these 3 structures are going to work.
4 No, I have a lot more. Now, that's the 5 good side.
6 On the bad side, for the staff, I'm not 7 sure that this is not a generic issue. I'm not sure 8 that all the other 100 plants out there, some of them 9 no have ASR issues.
10 So, I don't know, let's think about that 11 and see how we can communicate to them that there might 12 be a problem.
13 MR. DONOGHUE: One of the issues that we 14 have discussed before, related to subsequent license 15 renewal, is concrete degradation. And there's 16 continuing research on that.
17 And what we've -- the Commission has agreed 18 that plants can provide a plant-specific approach to 19 that, and there's three other issues, to be able to 20 pursue subsequent license renewal.
21 So, there is generic work underway that 22 the industry's pursuing, because they would -- it would 23 be easier to have a generic solution to that. So, I'll 24 just leave you with that.
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273 1 know, there's other applications, they have to address 2 concrete and other issues on a plant-specific basis 3 to obtain a subsequent license renewal approval.
4 MEMBER MARCH-LEUBA: Okay. I'm glad to 5 hear that, because this morning, the answer I understood 6 was, nobody else has a problem. That's what I 7 understood when I raised the issue at 8:35 this morning.
8 And obviously, that's not the case, so I'm glad to 9 hear that.
10 Final item, I'm sorry, it's not that late, 11 we have an hour ahead of schedule. I understand we 12 are going to have a full Committee meeting on the license 13 renewal and are we going to recommend that? I do 14 recommend that we have it.
15 CHAIRMAN SKILLMAN: Well, let's take it one 16 step at a time. We are having a license renewal meeting 17 for the Seabrook Station on November 15.
18 This meeting was specifically crafted to 19 address alkali-silica reaction, recognizing that there 20 are one, two, or three AMPs in the license renewal 21 application that address this topic.
22 So, the intention for this meeting was to 23 get the ASR issue resolved for the Committee, prior 24 to our getting to November 15.
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274 1 already have the safety evaluation, I've been reassured 2 that we now have the final signed documents. That is 3 our review target for November 15.
4 And presuming that we clear November 15 5 without issues, we go to the December full Committee 6 meeting with the intention of writing a letter.
7 MEMBER MARCH-LEUBA: Here is my question, 8 are we writing one letter or two?
9 CHAIRMAN SKILLMAN: We're going to discuss 10 that among ourselves or at P&P on Friday morning.
11 MEMBER MARCH-LEUBA: Okay. And with that, 12 I yield the remainder of my time.
13 (Laughter.)
14 CHAIRMAN SKILLMAN: Dr. March-Leuba, thank 15 you. Dr. Ballinger, sir?
16 MEMBER BALLINGER: I guess I'd like to sort 17 of echo what other people have said. I might add that 18 both the GALL-SLR and the Expanded Materials 19 Degradation Assessment, EMDA, documents, also all 20 require now that ASR and everything be explicitly 21 identified --
22 CHAIRMAN SKILLMAN: Addressed.
23 MEMBER BALLINGER: -- so, I don't think 24 we're going to have that issue any more. And lastly, 25 I still feel comfortable going to the Airfield Café NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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275 1 near Seabrook.
2 (Laughter.)
3 CHAIRMAN SKILLMAN: Thank you, Dr.
4 Ballinger. The distinguished Charlie Brown, Charlie?
5 MEMBER BROWN: I only had one observation, 6 probably being the least concrete familiar person on 7 the Committee.
8 I appreciated the NextEra and consultants 9 presenting of the data in what I would call English 10 and not burying it in very obscure jargonese, because 11 I actually understood what you were talking about as 12 you went through the analysis and stuff.
13 CHAIRMAN SKILLMAN: Minimum acronyms.
14 MEMBER BROWN: They did a good job and so 15 did the staff, in terms of their follow-up on the stuff, 16 so I thought it was a good presentation for, and it 17 was clean for somebody who not necessarily an expert 18 in that field. So, I appreciated that and I had no 19 other comments other than that.
20 CHAIRMAN SKILLMAN: Thank you, Charlie.
21 Dr. Bley, by chance are you still with us, please?
22 Dennis, are you there, please? Let's proceed. We have 23 our consultant, Dr. Schultz. Steve?
24 MR. SCHULTZ: Thank you. My objectives for 25 the meeting were all met in the presentations today.
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276 1 The summaries that were presented were 2 excellent and they were extremely helpful in clarifying 3 a number of issues, demonstrated comprehensive details, 4 demonstrating the approach developed for 5 investigation, testing, analysis, and monitoring 6 programs.
7 And the discussion really imparted that 8 the important features of the overall programs have 9 matured to implementation. And I was pleased that that 10 message was delivered today.
11 I was also pleased that NextEra clearly 12 is integrating the program into the site organization 13 at Seabrook. It's clear that the Station owns the 14 program and the ongoing resolution and monitoring for 15 the entire facility is in place and it's moving forward 16 in implementation.
17 I agree with the comment regarding the site 18 documentation on monitoring. It was a detailed slide 19 that was presented to us and we didn't go through it 20 in detail, but it clearly demonstrates that the 21 monitoring program is very well developed at Seabrook.
22 And the documentation that is being 23 provided for the program is going to be very valuable 24 moving forward, to allow the program to be successful, 25 because it's a very complex set of programs that come NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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277 1 together for this.
2 I also would like to really congratulate 3 the staff, as noted by Jose, for their involvement in 4 the inspection and oversight, for several years, 5 through here. Both the oversight and the documentation 6 related to it, in the inspection reports, and then, 7 carrying on into the safety evaluation.
8 It's very clear the level of detail and 9 the work that's gone into this review by the staff and 10 it shows in the detailed documentation that's been 11 developed for addressing this issue and going into the 12 license renewal safety evaluation as well.
13 I would just be repeating what I said 14 before, but it looks -- the license condition that's 15 been put forward for the longer term evaluation of the 16 testing program versus what is going to be learned from 17 Seabrook in the next five years and then, 15 years, 18 does look fairly complex to me.
19 And it's going to take a real investment 20 by NextEra to make that happen, I believe. And I'm 21 a little concerned that the experts that have 22 participated in our program today and in the 23 investigations over the last five years may not be 24 available to move forward with that investigation, so 25 I hope they're doing a lot of mentoring for their staff NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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278 1 moving forward to make sure that that is covered 2 comprehensively when it comes to pass.
3 But thank you all for your presentations, 4 I've learned a lot.
5 CHAIRMAN SKILLMAN: Thank you, Steve. I 6 would like to make several comments before we go to 7 public comment. When we began this meeting, I 8 identified several things that I was very interested 9 in hearing.
10 The first was to hear the staff and the 11 licensee communicate that they have a clear 12 understanding of the seriousness of the issue at 13 Seabrook Station.
14 That has been accomplished. I've heard 15 it from the staff, I've heard it from the licensee, 16 and I've heard it through the thoroughness of MPR and 17 SGH.
18 I communicated that I was looking or 19 listening for clarity regarding the scope of systems, 20 structures, and components affected by ASR. That has 21 been completed. It's clear in my mind that the licensee 22 and the staff understand the scope and understand the 23 importance of the scope.
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279 1 been fulfilled.
2 I communicated that I was listening for 3 a demonstration of the discipline. What I mean by that 4 is that what you do when you put on the seatbelt buckle 5 and get down and get busy and really get to the bottom 6 of the issue, the technical drive and the discipline 7 to understand the as-found state and the progression 8 of the phenomenon. And it's clear in my mind that that 9 has been fulfilled.
10 And I was interested in the thoroughness 11 of the licensee's plans, actions, and commitments.
12 To Dr. Schultz's comment, I believe that that which 13 will be codified as a consequence of the license 14 amendment will ensure that this endures for generations 15 to come.
16 I want to thank the staff, I want to thank 17 MPR, I want to thank SGH for their effort, very 18 comprehensive and very thorough. But I want to say 19 one or two other things.
20 I want to thank Theron for his effort to 21 put together a conference room that allowed us to do 22 this away from our normal conference space. So, 23 Theron, thank you, sir.
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280 1 we go to public comment, because I don't know what might 2 be coming.
3 With that, is there any individual in the 4 room that would care to come to the microphone and make 5 a comment? I invite you to do so and I ask you to speak 6 clearly into the mic, please come.
7 MR. NORD: Thank you. Wow, good evening.
8 I mean, this has been an amazing --
9 CHAIRMAN SKILLMAN: Would you please 10 introduce yourself?
11 MR. NORD: I'm sorry. I will say though, 12 that this has been an amazing thing to sit through.
13 My name is Chris Nord, N-O-R-D. I live in Newbury, 14 Massachusetts.
15 I have lived within the Emergency Planning 16 Zone for Seabrook for a good part of my adult life and 17 I'm a founding member and board member of the C-10 18 Research and Education Foundation in Newburyport, 19 Massachusetts.
20 We have operated the single largest 21 real-time citizens-run radiation monitoring network 22 in the United States for 25 years, under contract with 23 the State of Massachusetts, their Emergency Management 24 Agency, I believe is where we are now.
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281 1 at Seabrook, which is what got us involved years ago, 2 through discoveries of our researcher, the presence 3 of alkali-silica reaction at Seabrook, that has led 4 us to three different legal sessions concerning the 5 NRC.
6 One, a rulemaking petition. One, an 7 emergency enforcement action petition, which happened 8 two years ago. And in 2017, we were granted standing 9 before the Atomic Safety and Licensing Board, for one 10 overarching contention having to do with the license 11 amendment request.
12 And that contention has to do with the lack 13 of representativeness. We're challenging the 14 representativeness that NextEra claims that it has 15 established for the large-scale testing protocol at 16 Ferguson Labs.
17 So, my comments are going to be directed 18 toward helping clue you all in, so that you know who 19 we are, of the difficulties that we have with the license 20 amendment request and the order in which all of these 21 issues are coming out in the Nuclear Regulatory 22 Commission through its various agencies.
23 And I have tried through the day to shorten 24 and shorten how I might get this done, because I know 25 it's very late. So, I'm going to shortcut a lot of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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282 1 things.
2 We have submitted a document that came into 3 you all, highlighting some of our concerns, which you 4 will receive in writing, or have received digitally 5 already. So, let's see.
6 So, as I said, we have the overarching 7 contention challenging the representativeness of the 8 Ferguson large-scale testing. Among the -- it's at 9 least seven features of the safety evaluation that I 10 saw, we intend to directly challenge.
11 They included an inherent bias in the 12 testing methodology, challenging the notion that the 13 Ferguson testing yields improved data on limit states 14 that apply to Seabrook.
15 Challenging the rationale offered in 16 answer to RAI-T2, for the representativeness of 17 accelerated ASR. Challenging the sufficiency of an 18 independent internal peer review as a peer review in 19 the conventional sense.
20 And as an aside, I want to tell you that 21 we at the C-10 Foundation feel a tremendous burden of 22 responsibility right now, because we don't see any 23 opportunity, other than the one that is presented, to 24 this larger process, by our intervention in this 25 process, to actually have a peer review.
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283 1 This material is not being shown to the 2 wider scientific community to offer a peer review and 3 so, it falls to the expert witnesses that we are able 4 to bring to this, that are going to provide an 5 independent peer review.
6 Which is quite a burden for an organization 7 whose budget really concerns radiation monitoring.
8 This is a big thing for us to bite off. And I mean, 9 I'm not a scientist and none of us are scientists, we're 10 just doing the best we can with what we've got.
11 I just wanted to illustrate one of many 12 issues that we have and then, I'm leaving all the others 13 out.
14 The Section 3.2(a), which we saw in Page 15 29 of the draft safety evaluation, the rationale 16 expressed there for the use of accelerated ASR in the 17 Ferguson testing does not answer RAI-T2, Request 1, 18 with regard to Seabrook structures.
19 To claim that the use of fast-acting ASR 20 for research at Oak Ridge and NIST makes its 21 applicability as specifically representative of the 22 40-year-old concrete supporting structures sitting in 23 the uniquely harsh environment of the New Hampshire 24 Salt Marsh, is not an adequate scientific 25 justification.
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284 1 It is important to note here that because 2 of the long-term inundation of at least one structure, 3 the famous electrical cable tunnel, as it was called, 4 that was intended to be dry, Seabrook Station has 5 operated outside its design basis for its entire license 6 term.
7 If it is true that this reactor, being one 8 of the last commercial atomic plants to be licensed, 9 is coincidentally the first U.S. reactor to be found 10 with alkali-silica reaction, perhaps it behooves the 11 Nuclear Regulatory Commission and, by extension, ACRS, 12 with all respect, to look more closely at the Seabrook 13 Reactor itself to discover what has caused this 14 exceptional circumstance and not to be persuaded by 15 the licensee to look away from Seabrook's own data in 16 favor of an unprecedented and remote testing protocol.
17 Okay. I'm going to mix a couple of 18 metaphors and then, I'm going to finish. What I want 19 all of you in this Committee to understand is that from 20 the point of view of the C-10 Foundation, you all have 21 a freight train in your control that's rolling downhill.
22 And that freight train is occupying the 23 same track that we are, but we're moving much more 24 slowly. And that's because of the two different tracks 25 that we saw much earlier in the day that has this process NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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285 1 going along way before we have an opportunity to 2 litigate our case.
3 Therefore, I am not in a position to be 4 able to prosecute our case in front of the ACRS today, 5 because we're nine months away from being ready to go 6 to court.
7 But in the meantime, you all are somehow 8 being called upon by what we believe is a skewed process 9 to consider having some kind of a -- making some kind 10 of an advisory decision on the efficacy of this testing 11 protocol before we ever have a chance to litigate it.
12 And I mean, I just have to point out that 13 that is not a fair system. That is not a democratic 14 system.
15 So, the second metaphor, it has to do --
16 I'm going to give you a really short story. More than 17 30 years ago, a commercial atomic plant out on the edge 18 of the New Hampshire Salt Marsh was fully completed 19 with billions invested, before its evacuation plans 20 were ever adjudicated.
21 In fact, a majority of the towns within 22 the Emergency Planning Zone rejected the plans as 23 unfeasible, which we all believe actually they still 24 are, maybe even more so, because there are twice as 25 many people living there.
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286 1 And FEMA's Region I Chief sided with the 2 towns. What happened? The head of the Federal 3 Emergency Management Agency was replaced, the towns 4 were ignored, and the Atomic Safety and Licensing Board 5 put the plant online.
6 For those of us working for the safety of 7 Seabrook's neighbors for many decades, it seems that 8 the cart has been put before the horse once again.
9 The goals of a for-profit industry are 10 sometimes at odds with a fair and democratic process.
11 It is worse than unfortunate that the U.S. Nuclear 12 Regulatory Commission personnel concerned with 13 Seabrook's future are being pushed to consider a license 14 extension completely out of sequence with C-10's 15 capability to give voice to crucial issues that bear 16 directly on the plant's qualification to continue 17 operating.
18 There are nine instances where the NRC 19 staff finds reasonable assurance that the design 20 parameters, including building deformation compression 21 flexure strains on reinforcement in the external 22 seismic strain will be met.
23 The phrase reasonable assurance is a 24 subjective one. Would not beyond a reasonable doubt 25 be a higher standard?
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287 1 The goal of the NRC is to protect citizens 2 from exposure to some of the most toxic substances on 3 Earth, which is something that those of us that live 4 within the ingestion pathway for Seabrook, and many 5 of us live much closer, really take seriously.
6 Therefore, the most stringent standard should be 7 required.
8 Factoring in ASR as a design-basis load 9 would bring Seabrook closer to design-basis limits, 10 which would then become a causal factor in structural 11 failure brought about by internal and/or external 12 strain from beyond-design-basis events, accident, 13 attack, natural disaster.
14 While 40 years ago, it might have seem 15 implausible and unnecessary to worry over such events, 16 we now know such worries are not unfounded, while the 17 consequences of such an event occurring in one's own 18 community are truly unfathomable.
19 C-10 urges the Advisory Committee on 20 Reactor Safeguards, and by extension, the NRC, not to 21 allow the erosion of margins of safety built into 22 Seabrook's supporting walls by design and not to allow 23 the erosion of trust of residents of our EPZ.
24 We ask the federal regulators charged with 25 protecting us to hold NextEra to a higher standard.
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288 1 Lastly, we ask for assurance that the planned public 2 hearing on LAR 1603 be allowed to proceed before any 3 decision is made on Seabrook's request for a 20-year 4 extension for the plant's operating license. Thank 5 you.
6 CHAIRMAN SKILLMAN: Thank you for coming 7 to the microphone. Welcome to you and we respect your 8 participation here. Thank you.
9 MR. NORD: If you really do, give us a 10 chance.
11 CHAIRMAN SKILLMAN: Is there anyone else 12 in the room that would care to come to the microphone?
13 If so, would you please come and introduce yourself?
14 Hearing none, on the phone line, is there 15 any individual out there? If so, would you simply say 16 hello?
17 MR. WALDEN: Hello, this is Scott Walden.
18 CHAIRMAN SKILLMAN: Good afternoon, sir.
19 Now, to Scott and to anyone else, would anyone wish 20 to make a comment, please? If so, announce who you 21 are and then, please make your comment.
22 MR. WALDEN: Okay. This is Scott Walden.
23 I'd like to make a comment. I'm from Southern Nuclear 24 and I am the Chairman of the NEI License Renewal Civil 25 Structural Working Group.
NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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289 1 And I just wanted to say that, as an 2 industry, we are well aware of the alkali-silica 3 reaction and what has occurred and going on with 4 Seabrook.
5 And it's a common topic that we have at 6 our meetings, to discuss ASR, how we're going to address 7 it in the future, and looking at how we want to look 8 at things that are, what I would say, are leading 9 indicators, has been discussed with closing up gaps 10 and things like that.
11 So, we're, as a group, we're well involved 12 and working with EPRI. As a matter of fact, we're 13 looking at submitting at all of our structural 14 monitoring procedures to EPRI and next year, EPRI will 15 be putting out a report with that information, looking 16 at how we can develop commonality within the utility 17 group.
18 CHAIRMAN SKILLMAN: Thank you for your 19 comment, sir. Is there anybody else out there that 20 would wish to make a comment? If so, would you please 21 introduce yourself and make your comment?
22 MR. OSSING: Hello, my name is Mike Ossing, 23 from Marlborough, Massachusetts. Just a couple of 24 quick comments.
25 I would like to commend the NRC staff on NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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290 1 the thoroughness of their review. I thought it was 2 detailed and it took eight years to go through it and 3 that's right on point.
4 Reminded that ASR is a reaction and it does 5 take a while. I think the key to the whole process 6 is a robust monitoring plan, which I believe NextEra 7 has in place.
8 And I appreciate the thoughtful 9 deliberation by the ACRS Subcommittee. Thank you.
10 CHAIRMAN SKILLMAN: Thank you, sir. Is 11 there anybody else out there that would like to make 12 a comment? If so, please identify yourself and please 13 make your comment. Hearing none, Theron, please close 14 the phone line.
15 Colleagues, one last chance for comment.
16 I want to go around one last time. Vesna, any comment?
17 MEMBER DIMITRIJEVIC: No.
18 CHAIRMAN SKILLMAN: None? Mike, you good?
19 MEMBER CORRADINI: Yes.
20 CHAIRMAN SKILLMAN: Joy, good?
21 MEMBER REMPE: No more comments, thank you.
22 CHAIRMAN SKILLMAN: Pete, good?
23 MEMBER RICCARDELLA: I'm good.
24 CHAIRMAN SKILLMAN: Walt, good?
25 MEMBER KIRCHNER: No thank you.
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291 1 CHAIRMAN SKILLMAN: Jose, good?
2 MEMBER MARCH-LEUBA: No.
3 CHAIRMAN SKILLMAN: Dr. Ballinger?
4 MEMBER BALLINGER: No.
5 CHAIRMAN SKILLMAN: Honorable Charlie 6 Brown?
7 MEMBER BROWN: I'm good.
8 CHAIRMAN SKILLMAN: Dr. Schultz?
9 MR. SCHULTZ: No additional comments, thank 10 you.
11 CHAIRMAN SKILLMAN: Ladies and gentlemen, 12 thank you very much, we are adjourned.
13 (Whereupon, the above-entitled matter went 14 off the record at 6:24 p.m.)
15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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2 3
4 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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Evaluation and Management of Alkali Silica Reaction (ASR) at Seabrook Station Introduction and Background October 31, 2018 Speakers:
Kenneth Browne, NEE Seabrook Licensing Manager Michael Collins, NEE Seabrook Director of Engineering Edward Carley, NEE Seabrook Engineering Supervisor
The foundation for everything we do are the Values and Core Principles of our Nuclear Excellence Model 2
Key Personnel in Attendance:
NextEra Energy Seabrook NextEra Energy:
- Eric McCartney, Regional Vice President
- Larry Nicholson, Director of Fleet Licensing
- Michael Collins, Director of Engineering
- Kenneth Browne, Licensing Manager
- Jaclyn Hulbert, Engineer - Structures Monitoring Program
- Edward Carley, Engineering Supervisor
- David Robinson, Chemistry Manager 3
Key Personnel in Attendance:
MPR Associates, Inc. (MPR)
Personnel in Attendance: Key Efforts:
- John Simons
- Extent of Condition
- Amanda Card
- Interim Structural Assessment
- Christopher Bagley
- Large-Scale Testing Regarding Capacity
- Monitoring and Assessment of Expansion Behavior
Key Personnel in Attendance:
Simpson Gumpertz & Heger Inc. (SGH)
Personnel in Attendance: Key Efforts:
- Dr. Said Bolourchi
- Concrete Technology
- Glenn Bell
- Concrete testing & Petrography
- Matthew Sherman (PE)
- Inspections/Monitoring
- Michael Mudlock (PE)
- Methodology for Evaluating
- Liying Jiang ASR-affected Structures
- Dr. Andrew Sarawit
- ASR Load Factors
- Structural Evaluation
- Structural retrofit support
Technical Consultants in Attendance Dr. Oguzhan Bayrak (PhD, PE, F ACI)
- Ferguson Structural Engineering Laboratory (FSEL)
Dr. Bruce Ellingwood (PhD, PE, NAE, F SEI, Dist M ASCE)
- NEE Seabrook, Retired Structural Engineering Supervisor Robert Schofield
- ENERCON 6
SEABROOK BACKGROUND 7
Seabrook Background
- Seabrook Station is a single unit Westinghouse 4-loop pressurized water reactor with a General Electric turbine generator
- Located in the town of Seabrook, New Hampshire
- Two miles west of the Atlantic Ocean
- Approximately two miles north of the Massachusetts state line
- Approximately 15 miles south of the Maine state line
- Reactor housed in a steel lined reinforced concrete containment structure which is enclosed by a reinforced concrete containment enclosure structure
- 3648 MWt Thermal Power; ~ 1,250 net megawatts electric
- Atlantic Ocean is the ultimate heat sink
- A Seismic Category I mechanical draft cooling tower provides additional safe shutdown capability.
8
Seabrook
Background:
Plant Footprint N Hampton Beach Route 1
Seabrook Station Seabrook 600 ac. marshland Beach 300 ac. upland 9
Seabrook
Background:
Plant Layout 10
Seabrook
Background:
Licensing Timeline Construction Permit (CPPR-135) July 1976 Zero Power Operating License (NPF-56) October 1986 Low Power Operating License (NPF-67) May 1989 Full Power Operating License (NPF-86) March 15, 1990 Commercial Operation August 1990 Operating License Transfer to FPL Energy (NextEra) November 2002 Stretch Power Uprate (3587 MW) February 2005 Zero Power Recapture (3.4 years) December 2005 Measurement Uncertainty Uprate (3648MW) May 2006 LR Application Submitted May 25, 2010 Operating License Expires March 15, 2030 11
Status of ASR Effort at Seabrook Station Completed a comprehensive effort to:
- Conduct large-scale testing to understand the structural implications
- Develop methodology for evaluation of ASR-affected structures
- Evaluate Seismic Category I structures
- Develop monitoring strategies for ASR-affected concrete and associated SSCs Demonstrated compliance
- Seismic Category 1 structures comply with proposed licensing basis in LAR
- Modifications to several structures are underway Actively tracking developments in ASR research NextEra Energy Seabrook has implemented an effective program for evaluating and managing the impacts of ASR on affected concrete structures and associated SSCs 12
Purpose of Presentation Describe the comprehensive approach for addressing ASR at Seabrook Station Provide an overview of the technical basis for the ASR management approach
- Large-Scale Testing
- Methodology for evaluating ASR-affected structures Summarize implementation of the Structures Monitoring Program for aging management of ASR-affected structures 13
Presentation Outline ASR Background Approach for Addressing ASR Technical Basis for ASR Management Approach
- Large-Scale Test Programs
- Structural Evaluation Methodology for ASR-Affected Structures Implementation of ASR Management Approach
- Structures Monitoring Program
- Status of Relevant Licensing Actions
- License Amendment Request (LAR)
Conclusions and Closing 14
BACKGROUND OF ASR AT SEABROOK STATION 15
Background:
Discovery at Seabrook Station Initial Diagnosis
- Identified Pattern Cracking in the B Electrical Tunnel
- Performed Petrography on Cores (Confirmed ASR)
- Conducted Material Property Testing on Cores 16
Background:
Alkali-Silica Reaction (ASR)
K+ gel OH-SiO2 SiO2 forms + H2O SiO2 OH-Na+ gel alkali cement + expansive gel cracking of the reactive aggregate aggregate and paste 17
ASR in Countrys Infrastructure Photos courtesy of SGH 18
Background:
Causes of ASR
- Preventive measures taken during plant construction to prevent the development of ASR
- Aggregate reactivity testing Reactive
- Low alkali cement Aggregate
- Current state of knowledge
- Aggregate reactivity testing o ASTM test methods used during plant construction not reliable for slow reacting aggregates Alkali Moisture
- Limiting alkali content of cement o Not sufficient by itself to prevent ASR 19
Background:
Visual Indications of ASR 20
Background:
Implications of ASR Reduction in material properties and their effect on structural capacity
- Compressive strength
- Tensile strength
- Modulus of elasticity Effect of ASR expansion on structural demands
- Structural deformation Potential impact to plant systems and components 21
Approach for Addressing ASR at Seabrook Station Structural Capacity Large-Scale Testing Structures Monitoring Structural Structural Program UFSAR Evaluation Evaluation Methodology Structural Demand ASR Load Structural Field Data Factors Evaluation Updates Part 50 Part 54 22
Conclusions Large-Scale Test Programs
- No adverse impact of ASR on structural capacity within test limits
- Limits have been established for monitoring of plant structures Evaluation Methodology
- Defined process that considers the impact of ASR on both structural capacity and structural demands Structural Evaluations
- Demonstrate Seismic Category I structures comply with licensing basis Structures Monitoring
- Comprehensive program addresses ASR expansion, building deformation and impact on systems/components NextEra Energy Seabrook has implemented an effective program for evaluating and managing the impacts of ASR on affected concrete structures and associated SSCs 23
Evaluation and Management of Alkali Silica Reaction (ASR) at Seabrook Station Methodology for Structural Demand Evaluation of ASR-Affected Structures October 31, 2018 Speakers:
Simpson Gumpertz & Heger Inc. (SGH)
- Dr. Said Bolourchi,
- Glenn Bell,
- Matthew Sherman Supporting Personnel:
- Dr. Bruce Ellingwood
Structural Evaluation Methodology
- Define a consistent and repeatable analysis and evaluation methodology for all Seismic Category I structures
- Apply the methodology to evaluate structures to show:
Structural Capacity Structural Demand
- No impact on Code capacity
- Change in stiffness relates to
- Field data for ASR status the prestressing effect
- Modeling to account for ASR-induced prestressing 2
Why does ASR Change the Demand?
- If concrete is unrestrained, ASR causes expansion in the concrete, but no forces develop in the structure.
- If concrete is restrained, forces develop in the structure.
- This restraint can come from:
- Reinforcement
- Other segments of the same structure
- Adjacent structures
- Surrounding bedrock
- These forces must be considered, as they were not part of the original design basis defined in the UFSAR.
ASR-affected structures must be evaluated 3
Structural Evaluation Methodology for ASR-Affected Structures Presentation Outline
- Evaluation of all Seismic Category I structures at Seabrook is based on UFSAR and defined in the Methodology Document
- Structural Evaluation Methodology:
- ASR Loading and Load Factors
- Methodology Document
- Methodology Document provides details for collecting field data and evaluating all Seismic Category I structures at Seabrook Station 4
ASR Load Factors Supplement the original design load effects with ASR loads, while maintaining the level of structural performance implicit in the original design criteria and codes
- Determine the appropriate ASR load factors to supplement ASME Section III 1975 and ACI 318-71 load combinations 5
Load Factor Principles Containment Building All Category I Structures other than ASME Section III 1975 Containment Building ACI 318-71 Allowable Stress Design Strength Design Primary objective: Limit stresses in Primary objective: Assure adequate strength.
concrete and steel reinforcement.
6
CONTAINMENT BUILDING ASME SECTION III 1975 7
Containment Building ASME Section III 1975
- Service Load Conditions: Construction and normal plant operation conditions that act frequently. Concrete stresses well below compressive strength, steel stresses well below yield.
- Factored Load Conditions: Severe and extreme environmental and abnormal conditions that act infrequently. Permitted stresses higher than for Service Load Conditions but generally below concrete compression and steel yield strengths.
8
Containment Building
Si = Load Effects (Dead, Live, Earthquake, ASR, etc.)
= Load Factors associated with each Load Effect Fa = allowable stress = Fcr Fcr = critical stress
= stress partial factor of safety
- Loads are deterministic: established by positing various scenarios.
- Most load factors = 1.0. Some 1.25 to 1.5 for severe environmental or abnormal condition load combinations.
9
Containment Building Develop ASR loads that have a very small likelihood of exceedance and use an ASR load factor of 1.0
- Consistent with the deterministic philosophy used in the development of ASME Table CC-3230-1 10
Containment Building Zone 1 Zone 2 Zone 3 Zone 4 No ASR in No ASR in No ASR in Zone 2 Zone 3 Zone 4 0.1 CI < 0.5 0.5 CI < 1.0 1.0 CI < 2.0 CI 2.0 mm/m mm/m mm/m mm/m Applied ASR at Zone 1 = 0.6 Zone 1 0.0 0.1 0.5 0.6 1.0 Methodology
- Map the Containment Building into the four zones of ASR severity (Containment Building has only Zone 1 ASR)
- Apply to the entirety of each zone an ASR strain corresponding to the upper limit of CI in that zone and increase it by 25%
- Apply to this conservative ASR loading a load factor of 1.0 11
Containment Building Schematic Illustration Equipment Hatch 12
Why this Approach is Conservative
- The highest level of strain in each zone is applied to the entire zone
- An additional 25% margin is added to that highest level of strain
- The Large Scale Testing Program demonstrated that, on average, CI measurements conservatively predict ASR strain
- The literature shows that ASR strains measured at the concrete surface over predict strains at reinforcement depth For each load combination, a conservative value of ASR strain is applied for each ASR zone in combination with a load factor of 1.0.
13
SEISMIC CATEGORY I STRUCTURES OTHER THAN CONTAINMENT BUILDING ACI 318-71 14
Category I Structures Other Than Containment Building ACI 318-71
- Strength is checked via code equations that assess a reinforced concrete members maximum achievable strength.
- Supplementary serviceability checks made under less extreme loading conditions.
15
Category I Structures Other Than Containment Building
Si = Load Effects (Dead, Live, Earthquake, ASR, etc.)
= Load Factors associated with each Load Effect R = nominal strength capacity
= strength reduction factor Load factors for strength checks generally between 1.4 and 1.7, but in load combinations involving wind, seismic, and accident conditions they may be lower.
16
Load Factors of ACI 318-71
- Ellingwood et al. established the inherent reliability of ACI 318-71 for use in probability-based design
- Adopt the same probabilistic approach to establish ASR load factors for use with ACI 318-71
- Average reliability indices () found in NBS study are used as basis for calculation of ASR load factors:
- For gravity load combinations: 3.0
- Load combinations with wind: 2.5
- For load combinations including the Operating Basis Earthquake: 1.75 The NBS Report 17
Approach for Application of ACI 318-71 to Category I Structures Other than the Containment Building Zone 1 Zone 2 Zone 3 Zone 4 CI < 0.5 0.5 CI < 1.0 1.0 CI < 2.0 CI 2.0 mm/m mm/m mm/m mm/m
- For each zone determine ASR strains from CI statistics gathered over those zones in the entire plant
- Map the four ASR severity zones onto each structure
- Apply an ASR strain corresponding to the mean value of CI measured in each zone
- Apply a probabilistically determined load factor as described in the following slides 18
Calculation of ASR Load Factors Input Variable How Addressed Based on NBS Report for Target reliability, each load combination as previously described Probability distribution Calculation that Based on NBS Report finds the ASR load of structural resistance factor that results in Probability distribution Based on NBS Report the target reliability of non-ASR load effects for each type of From statistics of CI load combination Probability distribution measurements taken at of ASR load effects the plant Representative values Ratio of ASR load effects calculated for each ASR to total load effects, Kasr zone 19
ASR Load Factors for Use with ACI 318-71 ASR Load Factor Load Combination Zone 1 Zones 2-4 Static 2.00 1.60 Wind 1.70 1.36 OBE 1.30 1.04 Notes:
- Per ACI 318-71, for load combinations involving differential settlement, creep, shrinkage, or temperature change, load factors may be reduced by 25% but may not be less than 1.0.
20
Key Conclusions Regarding ASR Load Factors ASR load factors were developed to:
- Be added to UFSAR design load combinations
- Be consistent with the underlying philosophy of the original design criteria and codes ASR load factors maintain the level of reliability and margin of safety inherent in the codes of record.
21
Independent Review by Dr. Bruce Ellingwood
- For the Containment Building the methods employed for revising the load combinations to account for the structural actions due to ASR are entirely consistent with the deterministic approach to safety assurance historically taken in developing the ASME Code.
- For those Category I structures other than the Containment Building, the proposed modifications to the original design load combinations to account for the structural actions due to ASR will maintain the target reliability indices provided by the load combinations of ACI 318-71.
- This conclusion is based, in part, on independent calculation checks of reliability indices.
22
Field Data 23
Use of Field Data Data Analysis Interpretation Field Data (Observations &
Measurements) 24
Field Data Overview Observations: Non-quantifiable information and guidance Measurements: Quantifiable information and data used directly in analysis Specialty Testing: Supporting or interpretive information and data 25
OBSERVATIONS 26
Field Data - Observations:
Visual, Sounding Cracks Enhanced with Chalk 27
Field Data - Observations:
Crack Patterns and Relative Movement Diagonal Cracks (Enhanced with Chalk)
Movement of Flex Joint/Connector 28
EXPANSION MEASUREMENTS 29
Field Data - Expansion Measurements:
Cracking Index Cracking Index (CI) and Combined Cracking Index (CCI)
- Optical measurement
- Provides indication of ASR expansion-to-date 30
Field Data - Expansion Measurements:
Cracking Index w1 w2
- Lay out measurement line
- Measure crack widths where L they cross the line
- Add together measured widths
- Divide by total length
+
=
31
Field Data - Expansion Measurements:
Cracking Index example Area with suspect ASR cracking 32
Field Data - Expansion Measurements:
In-Plane Expansion In-plane pin-to-pin expansion
- Higher-precision mechanical measurement
- Used in monitoring program for measuring ongoing changes 33
Field Data - Expansion Measurements:
Through-Thickness Expansion
- Used in monitoring program for confirmation that the structure and associated analyses remain within the bounds of the FSEL testing.
34
DEFORMATION MEASUREMENTS 35
Concrete Backfill CEVA 20 RCA PAB EL (+)7-0 EL (+)7-0 10 TUN.
EL (+)3-0 FUEL STORAGE BLDG. EL (-)0-0 EL (-)2-0 Concrete backfill 0
-10 EL (-)15-91/2
-20 EL (-)20-9 Rock Section Cut View
- The station was built into the excavated bedrock.
- Construction used concrete as backfill between the final structure and the excavation face.
- Backfill concrete is of the same type and composition as the structural concrete.
36
Field Data - Deformation Measurements
- Plumbness measurements -
- Levelness measurements -
Wall structure Slab structure 37
Field Data - Deformation Measurements (contd)
- Seal/gap width measurements
- Annulus width measurements 38
SPECIALTY TESTING 39
Field Data - Specialty Testing: Petrography
- To investigate if in-plane expansion is caused by mechanisms other than internal ASR expansion 40
Field Data - Specialty Testing: Petrography
- Petrography to determine expansion mechanisms 41
Key Conclusions Regarding Field Data Field Data provide:
- Input data, feedback, and correlation to support modeling
- Reference values for future monitoring in Structural Monitoring Program Field data support evaluation and future monitoring.
42
Structural Evaluation Methodology
- Define a consistent and repeatable analysis and evaluation methodology for all Seismic Category I structures
- Establish threshold limits for potential future ASR expansion 43
ASR Structural Evaluation Process Load combinations and load factors UFSAR (As Amended by the License Material properties Amendment Request) Graded analysis approach Codes supplements Methodology Document Analysis Approach Repeatable analyses process Graded approach field data Threshold Limits Design margin for future ASR expansion Structural Evaluation Structural Capacity Structural Demands Parameters monitored and frequency Structures Monitoring Program Trending Action if approaching threshold limits 44
Threshold Definition
- The threshold limit, ( ), is additional margin to accommodate demands associated with future ASR growth.
+ ( )
Capacity Sum of factored Factored design-basis loads ASR load Where:
R = Nominal strength
= Capacity reduction factor
= Original design load (Dead, Live, Earthquake, etc.)
= ASR Load
= Load Factors associated with each of original design load
= Load Factor associated with ASR load kth = Threshold Factor 45
Field Data
- Walkdown observations
- Graded approach for field data collection
- Typical Field Data include
- In-plane strain: CI, CCI, and Pin-to-pin
- Changes in seismic isolation gaps
- Structural deformation
- Structural distress
- Crack width
- Adjusted in-plain strain for:
- Cracks not indicative of ASR which could be due to:
pressurization, temperature, differential ASR between regions, structural deformation, other design loads.
- Petrography confirmation 46
Graded Analysis Approach Review Design Review SMP Initial Data Walkdown Documents Select Analysis Stage Stage One Stage Two Stage Three Most Conservative Evaluation Conservative Evaluation Refined Evaluation
- Original design demands
- Original design demands
- Correlate finite element
- Conservative ASR
- ASR with finite element model with field data analysis
- All demands using finite element analysis
- 36 Months Monitoring
- 18 Months Monitoring
- 6 Months Monitoring 47
Stage Three Analysis Stage Three Correlate Finite Element Model with field data
- Increase demands by threshold factor for future ASR growth Is No No Capacity Re-evaluation Demand Retrofit Yes
- Meets licensing basis as amended by LAR
- Threshold limits, reference values
- Monitoring every 6 months 48
Correlating Analysis Model to Field Observation Containment Enclosure Building Analysis Input: Analysis Method: Analysis Output:
- Correlate to field data ASR CI Measurements, CEB
+
GL-2 GL+2 Compare deformation Undeformed Shape Standard-Plus Analysis Case w/ Cracking Standard Analysis Case w/ Cracking Field Data at EL 22.25 ft +/- 5.0 ft Deformations scaled by 100X. Small gray dots represent 1.00 in. grades of deformation.
Concrete backfill pressure due Meridional Strain to ASR expansion
+ Azimuth Compare strain Other sustained loads 49
Key Attributes of Modeling
- General purpose finite element analysis software ANSYS is used for modeling structures.
- Internal ASR effects on reinforced concrete structures are simulated:
- Prestressing effects are captured by applying CI measured strain to concrete portion of reinforced concrete elements.
- Concrete backfill expansions are captured by vertical and lateral pressures applied to structure.
- Effects of structural cracking are captured by reducing member section properties.
50
Concrete Backfill Simulation The impacts of ASR expansion of concrete backfill are back-calculated by correlating structural responses to field data.
- Direct concrete backfill testing and strain measurements are not feasible because of inaccessibility.
CEVA 20 RCA PAB EL (+)7-0 EL (+)7-0 10 TUN.
EL (+)3-0 FUEL STORAGE BLDG. EL (-)0-0 EL (-)2-0 Concrete backfill 0
-10 EL (-)15-91/2
-20 EL (-)20-9 Rock Section Cut View 51
Concrete Backfill Lateral Pressure
- Set lateral pressure equal to overburden pressure
- Reduce lateral pressure to simulate overall deformations GL-2 GL+2 Undeformed Shape Standard Analysis Case w/ Cracking Standard-Plus Analysis Case w/ Cracking Field Data at EL 22.25 ft +/- 5.0 ft GL-2 GL+2 Undeformed Shape Deformations scaled by 100X. Small Analysis Standard gray dots represent Case w/ 1.00 in. grades Cracking of deformation.
Standard-Plus Analysis Case w/ Cracking Field Data at EL 22.25 ft +/- 5.0 ft Deformations scaled by 100X. Small gray dots represent 1.00 in. grades of deformation.
- Reduce lateral pressure to simulate flexural crack initiation when structural cracks are not observed 52
LAR Code Supplements
- Acceptance criteria remain as original Code of Record (ASME Section III 1975; ACI 318-71) as supplemented by the LAR Supplements Supplemented Document 1 - Add the ASR load and load factors to UFSAR load combinations UFSAR & ACI 318-71 ASME Section III 1975 2 - Code-defined strengths not impacted for members affected by ACI 318-71 ASR expansion ASME Section III 1975 3 - Analyze shear-friction capacity per ACI 318-83, Section 11.7 ACI 318-71 4 - Reduce section property to 50% of gross section property to ACI 318-71 account for flexural cracking 5 - Reduce axial and shear stiffness to account for cracking ACI 318-71 53
Threshold Parameters
- Structure specific threshold parameters are selected for structural monitoring program
- Selected threshold parameters can be quantitative and qualitative parameters
- Structure specific threshold parameters are a subset of parameters defined in Methodology Document including:
- In-plane expansion
- Through-thickness expansion
- Seismic joint width
- Structural deformation
- Crack lengths and widths 54
Key Conclusions of Structural Evaluation Methodology Structural Evaluation Methodology provides:
- ASR load factors that maintain the level of reliability inherent in the codes of record
- Repeatable graded approach for analysis and evaluation process
- Threshold factor, parameters, and monitoring frequency Repeatable analysis and evaluation process applicable for all Seismic Category I structures at Seabrook 55
Structural Evaluation
- Evaluate each structure using the Structural Evaluation Methodology
- Establish ASR threshold limits, parameters, baseline values, and frequency of monitoring for each structure Structural Capacity Structural Demand 56
Evaluations of Seismic Category I Structures
- All Seismic Category I structures are evaluated:
- Confirm structure meets Code of record.
- Determine Threshold Factor for each structure, which is the margin available to accommodate future ASR expansion.
- Define parameters, reference values, and limits to be monitored, and monitoring frequency.
- Identify structural areas that may require enhanced monitoring or retrofits.
- Evaluation status:
Analysis Stage Status of Number of Threshold Factor Evaluation Packages Evaluation Packages One Two Three Completed 19 7 6 6 1.2 - 3.7 In progress 8 1 4 3 TBD 57
Key Conclusions of Structural Evaluation Seismic Category I structures are evaluated to meet acceptance requirements of UFSAR and the Structural Evaluation Methodology
- Provided ASR threshold factor, parameters, reference values, and monitoring frequency.
- Defined action required for structural members.
Seabrook Seismic Category I Structures are evaluated to meet the UFSAR and Structural Evaluation Methodology requirements.
58
Evaluation and Management of Alkali Silica Reaction (ASR) at Seabrook Station Implementation of ASR Management Approach at Seabrook Station October 31, 2018 Speakers:
Jaclyn Hulbert, NEE Seabrook Engineer - Structures Monitoring Program Edward Carley, NEE Seabrook Engineering Supervisor Michael Collins, NEE Seabrook Director of Engineering Kenneth Browne, NEE Seabrook Licensing Manager
Current Status at Seabrook Station Presentation Outline Structures Monitoring Program
- Monitoring Efforts
- Monitoring Parameters and Acceptance Criteria
- Monitoring Locations
- ASR Progression and Expansion at Seabrook Station
- Current Level of ASR Progression Status of Relevant Licensing Actions
- License Amendment Request (LAR)
STRUCTURES MONITORING PROGRAM 3
Structures Monitoring Program Structural Capacity Large-Scale Testing Structures Monitoring Structural Structural Program UFSAR Evaluation Evaluation Methodology Structural Demand ASR Load Structural Field Data Factors Evaluation Updates Part 50 Part 54 4
Structures Monitoring Program Overview
- Comprehensive Structures Monitoring Program that incorporates identification, evaluation, and monitoring of ASR-affected structures and associated SSCs
- Structures Monitoring Maintenance Rule 10CFR50.65
- ASR Monitoring
- Building Deformation Monitoring
- Equipment Impacted by Structural Deformation Monitoring
- Training program to increase awareness of ASR expansion and ASR-induced building deformation at Seabrook Station
- Web-based training for all personnel badged at Seabrook
- Focused training for departments that are inside plant structures on a frequent basis 5
Structures Monitoring Program Overview 6
Structures Monitoring Program Overview 7
Monitoring Parameters and Acceptance Criteria for ASR-Affected Concrete and Associated SSCs Parameter Acceptance Criteria Frequency Expansion Limits from the Large-Scale Based on the level of in-plane
- In-Plane Testing expansion
- Through-Thickness
- In-plane: 30, 18, or 6 month
- Volumetric basis
- Through-thickness and Volumetric: 6 month basis Structural Deformation Thresholds from the Structural Based on results from the Structural
- Seismic Gaps Evaluations (Building-Specific) Evaluation (Building-Specific)
- Annulus Width (CEB)
- 36, 18, or 6 month basis
- Plumbness
- In-Plane Expansion
- Observations
- Sounding SSCs attached to ASR-affected structures are monitored at least every two years to ensure functionality is not lost. Corrective action is taken if an adverse condition is noted.
8
Monitoring Locations CCI/In-Plane Expansion Grids
- Total of 136 locations for ASR in-plane expansion monitoring
- 21 additional grids have been established for deformation monitoring only Extensometer/Through-Thickness Expansion
- Total of 48 currently installed
- ~ 200 cores taken for material property testing (compressive strength and elastic modulus)
- Expansion to date was determined using the modulus correlation methodology 9
Monitoring Locations (contd)
Deformation Monitoring Locations
- 24 structures currently monitored Seismic Gap Measurements (between Crack Gauge adjacent Measurements structures)
In-plane expansion Annulus Measurements (between CEB and Containment) 10
ASR Progression at Seabrook Station Expansion levels are within Large-Scale Testing limits Structures within Thresholds from the Structural Evaluations
- Expansion levels
- Deformation Expansion at Seabrook Station is slow
- Monitoring intervals are sufficient to ensure that limits are not approached prior to the next inspection interval 11
STATUS OF RELEVANT LICENSING ACTIONS 12
License Amendment Request (LAR)
Rationale for LAR
- Original design basis did not include consideration of ASR loads
- Incorporates Evaluation Methodology and Large-Scale Test Program results
- Includes provisions for monitoring Status: Pending
- Submitted in August 2016
- Draft SE in September 2018 13
License Renewal Application (LRA)
ASR monitoring and management efforts in the Structures Monitoring Program (SMP) are carried forward in the Aging Management Programs (AMP)
- Structures Monitoring Program
- Building Deformation AMP (also considers SSC functionality)
Status: Pending
- Subcommittee Meeting
- November 15, 2018
- Full Committee Meeting
- December 6, 2018 14
Open Item - Structures Monitoring Program OI 3.0.3.2.18-1
- Aging management of concrete structures affected by Alkali-Silica Reaction (ASR).
Resolution
- LRA updated to augment existing Structures Monitoring Program by addition of plant specific Alkali-Silica Reaction (ASR) and Building Deformation (BD) Aging Management Programs.
- Aging management of ASR has been integrated into the Section XI IWL Program.
Inspection, tracking and evaluation are in accordance with guidance of ACI 349.3R.
NextEra has implemented a program that effectively evaluates and manages the aging effects of ASR on affected concrete structures and associated SSCs 15
CONCLUSIONS 16
Approach for Addressing ASR at Seabrook Station Structural Capacity Large-Scale Testing Structures Structural Monitoring Structural Program UFSAR Evaluation Evaluation Methodology Structural Demand ASR Load Structural Field Data Factors Evaluation Updates Part 50 Part 54 17
Completed Seismic Category I Structural Evaluations Threshold Evaluation Stage Action Required Factor Containment Internal Structures 1 No ASR Service Water Access Vault 1 No ASR Containment Building (CB) 1 1.8 Containment Equipment Hatch Missile Shield 1 1.5 Relieve rebar stress on North wall Containment Enclosure Ventilation Area and RCA Tunnel 1 3.0*
(design is completed)
Safety-related Electrical Manholes (7 units) 1 3.0 Enhanced monitoring and develop retrofit for Electrical Cable Tunnel (North) 1 1.3*
future bracing the of the walls Condensate Storage Tank Enclosure 2 1.6 Pre-Action Valve Building 2 1.3 Main Steam & Feedwater Pipe Chase -West & Personnel Hatch 2 1.8 Main Steam & Feedwater Pipe Chase - East & Hydrogen Recombiner 2 1.5 Room Reevaluate or retrofit the below grade walls at Primary Auxiliary Building 2 1.5*
elev. 7 Safety-related Electrical Manholes (6 Units) 2 1.5 to 1.7 Containment Enclosure Building (CEB) 3 1.3 Missile shield CEB to CB Seismic Gap restored Control Room Makeup Air Intake Structure 3 1.4 Residual Heat Removal (RHR) Equipment Vault 3 1.2 Fuel Storage Building 3 1.2 Retrofit north and south walls between elevs. -
Mechanical Penetration 3 1.5*
26 to +1 Service Water and Circulating Water Pumphouse 3 1.4
- After proposed/completed action 18
Conclusions NextEra completed a comprehensive effort to:
- Conduct large-scale testing to understand the structural implications ASR
- Develop methodology for evaluation of ASR-affected structures
- Evaluate ASR-affected structures
- Develop monitoring strategies for ASR-affected concrete and associated SSCs Structural Evaluations Demonstrate Seismic Category 1 structures comply with licensing basis NextEra has implemented a program that effectively evaluates and manages the impacts of ASR on affected concrete structures and associated SSCs 19
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