ML18310A112
| ML18310A112 | |
| Person / Time | |
|---|---|
| Issue date: | 10/17/2018 |
| From: | Quynh Nguyen Advisory Committee on Reactor Safeguards |
| To: | |
| Nguyen Q | |
| References | |
| NRC-3931 | |
| Download: ML18310A112 (231) | |
Text
Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION
Title:
Advisory Committee on Reactor Safeguards Regulatory Policies and Practices Docket Number: (n/a)
Location: Rockville, Maryland Date: Wednesday, October 17, 2018 Work Order No.: NRC-3931 Pages 1-231 NEAL R. GROSS AND CO., INC.
Court Reporters and Transcribers 1323 Rhode Island Avenue, N.W.
Washington, D.C. 20005 (202) 234-4433
1 1
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 1 UNITED STATES OF AMERICA 2 NUCLEAR REGULATORY COMMISSION 3 + + + + +
4 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 5 (ACRS) 6 + + + + +
7 REGULATORY POLICIES AND PRACTICES SUBCOMMITTEE 8 + + + + +
9 WEDNESDAY 10 OCTOBER 17, 2018 11 + + + + +
12 ROCKVILLE, MARYLAND 13 + + + + +
14 The Subcommittee met at the Nuclear 15 Regulatory Commission, Three White Flint North, Room 16 1C3 & 1C5, 11601 Landsdown Street, at 1:00 p.m.,
17 Walter Kirchner, Chairman, presiding.
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2 1 COMMITTEE MEMBERS:
2 WALTER KIRCHNER, Chairman 3 MICHAEL L. CORRADINI, Member 4 RONALD G. BALLINGER, Member 5 DENNIS C. BLEY, Member*
6 CHARLES H. BROWN, JR., Member 7 MARGARET SZE-TAI Y. CHU, Member 8 PETER RICCARDELLA, Member 9 HAROLD B. RAY , Member 10 MATTHEW SUNSERI, Member 11 12 DESIGNATED FEDERAL OFFICIAL:
13 QUYNH NGUYEN 14 15 16 *Present via telephone 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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3 1 C-O-N-T-E-N-T-S 2 Opening Remarks . . . . . . . . . . . . . . . . . 4 3 Introductions and Overview . . . . . . . . . . . 6 4 Selected Safety Analysis Sections: TVA . . . . . 11 5 Geologic Characterization and Surface 6 Deformation 7 Vibratory Ground Motion 8 Stability of Subsurface Materials and 9 Foundations and Stability of Slopes 10 Selected Safety Analysis Sections: NRC Staff . . 68 11 Geologic Characterization and Surface 12 Deformation . . . . . . . . . . . . . 102 13 Vibratory Ground Motion 14 Stability of Subsurface Materials and 15 Foundations and Stability of Slopes . 120 16 Public Comment . . . . . . . . . . . . . . . . 129 17 Adjourn . . . . . . . . . . . . . . . . . . . . 130 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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4 1 P R O C E E D I N G S 2 12:59 p.m.
3 CHAIRMAN KIRCHNER: Good afternoon. You 4 need a click to go. Okay, the meeting will now come 5 to order. This is a meeting of the Regulatory 6 Policies and Practices Subcommittee of the Advisory 7 Committee on Reactor Safeguards. I am Walt Kirchner, 8 Chairman of this Subcommittee meeting.
9 ACRS members in the room are, I have to 10 take my glasses off, Charles Brown, Ron Ballinger, 11 Harold Ray, Matt Sunseri, Pete Riccardella, Mike 12 Corradini, and Margaret Chu. And I believe we're 13 expecting Vesna Dimitrijevic. And also I think we 14 have Dennis Bley on the line.
15 Quynh Nguyen of the ACRS staff is the 16 Designated Federal Official for this meeting. This 17 turns out to be the fourth meeting of this 18 subcommittee on the topic. Today, the Subcommittee 19 will hear from representatives of TDA and the staff 20 regarding the following sections of the Clinch River 21 early site permit application and the corresponding 22 safety evaluation: geological characterization and 23 surface deformation, 2.5.1 and 2.5.3; a vibratory 24 ground motion, 2.5.2; and stability of subsurface 25 materials and foundations and stabilities of slopes, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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5 1 that's 2.54 and 2.5.5.
2 The Subcommittee will gather information, 3 analyze relevant issues and facts, and formulate 4 proposed positions and actions as appropriate for 5 deliberation by the full Committee.
6 The ACRS was established by statute and is 7 governed by the Federal Advisory Committee Act, FACA.
8 This means that the Committee can only speak through 9 its published letter reports. We hold meetings to 10 gather information to support our deliberations.
11 Interested parties who wish to provide comments can 12 contact our offices requesting time after the meeting 13 announcement is published in the Federal Register.
14 That said, we also set aside some time for 15 spur of the moment comments from members of the public 16 attending or listening to our meetings. Written 17 comments are also welcome. In regard to early site 18 permits, 10 CFR 52.23 provides that the Commission 19 shall refer a copy of the application to the ACRS, and 20 the Committee shall report on those portions which 21 concern safety.
22 The ACRS section of the US NRC public 23 website provides our charter, bylaws, letter reports, 24 and full transcripts of all full and Subcommittee 25 meetings, including slides presented at the meetings.
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6 1 The rules for participation in today's meeting were 2 previously announced in the Federal Register. We have 3 received no written comments or requests for time to 4 make oral statements from members of the public 5 regarding today's meeting.
6 We have a bridge line established for 7 interested members of the public to listen in. To 8 preclude interruption of the meeting, the phone bridge 9 will be placed in a listen-in mode during the 10 presentations and Committee discussions. We will 11 unmute the bridge line at a designated time to afford 12 the public an opportunity to make a statement or 13 provide comments.
14 At this time, I request that meeting 15 attendees and participants silence their cellphones 16 and any other electronic devices that are audible. A 17 transcript of the meeting is being kept and will be 18 made available as stated in the Federal Register 19 notice. Therefore, we request that participants in 20 this meeting use the microphones located throughout 21 the meeting room when addressing the Subcommittee.
22 The participants should first identify 23 themselves and speak with sufficient clarity and 24 volume so that they may be readily heard. Make sure 25 that the green light of the microphone is on before NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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7 1 speaking, and off when not in use.
2 We will now proceed with the meeting, and 3 I call upon Andy Campbell of NRO to begin. Andy.
4 MR. CAMPBELL: Good afternoon, my name is 5 Andy Campbell, I'm the Deputy Director for the 6 Division of Licensing, Siting, and Environmental 7 Analysis in the Office of New Reactors. With me today 8 are a number of staff from DLSC involved in this 9 project, Alan Fetter, Mallecia Sutton, Garry 10 Stirewalt, Jenise Thompson, David Heeszel, Luissette 11 Candelario, Weijun Wang.
12 And I will let the TVA folks introduce 13 themselves.
14 So this is the third of four Subcommittee 15 meetings for the staff evaluation, the safety 16 evaluation, with no open items. Let me repeat that, 17 we have no open items.
18 First, ESP from an SMR plant design, the 19 review has been proceeding as scheduled, and you'll 20 hear today about the geology and ground information 21 aspects of that safety evaluation. We look forward to 22 continued fruitful dialog with the Advisory Committee 23 on Reactor Safeguards as this ESP review continues 24 moving forward.
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8 1 be November 14, I believe. And so with the full 2 Committee of the Advisory Committee on Reactor 3 Safeguards scheduled for December 5.
4 And so with that full Committee meeting 5 and any letter the Committee wishes to write, we would 6 be closing out Phase C of our review. So with that, 7 I'll turn it back to you. I want to thank everyone 8 and thank the staff and thank TVA for coming in and 9 supporting this review.
10 CHAIRMAN KIRCHNER: Thank you, Andy. So 11 we'll turn to TVA. Ray, are you going to make the 12 introductions, or is Wally? Go ahead, Ray.
13 MR. SCHIELE: Good afternoon, my name is 14 Ray Schiele and I'm the Licensing Manager for the 15 Clinch River early site permit application. I have 16 over 44 years in the nuclear industry, including 17 United States Navy, plant operations, and licensing.
18 TVA would like to thank Chairman Kirchner 19 and the rest of the Subcommittee for their support in 20 the review of this early site permit application.
21 This slide is an acknowledgment of the 22 relationship between DOE and TVA and the associated 23 responsibilities of that relationship.
24 Overview of TVA's mission. TVA's mission 25 includes partnering with over 154 local power NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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9 1 companies serving more than nine million people in a 2 service area that covers seven states. TVA directly 3 serves over 54 large industries and federal 4 installations.
5 This slide is a review of our schedule 6 thus far. The first section here we're going to talk 7 about is the safety review. Today's meeting is the 8 fourth of five planned Subcommittee meetings.
9 Previous meetings included an overview of the project, 10 sections on geography, tomography, aircraft hazards, 11 radiological consequences of design-based accidents, 12 emergency planning, and EPZ sizing.
13 Today, TVA will be presenting Section 2.5, 14 geology, seismology, and geotechnical engineering.
15 The final Subcommittee meeting, scheduled for November 16 14, will cover Sections 2-3, meteorology; 2-4, 17 hydrology; 11-2 and 11-3, radiological effluent 18 releases; and 17, which is quality assurance.
19 So as you can see, we're well ahead of the 20 proposed FSER issuance of August of '17. The 21 Environmental Review was issued, the DEIS was issued 22 five weeks early. The NRC is on or ahead of the 23 published schedule for the review and disposition of 24 DEIS comments. TVA is looking forward to an early 25 issuance of the FEIS. And this is the basic Gantt NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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10 1 chart for the Environmental Review.
2 The hearing. In July of 2018, the ASLB 3 dismissed the last remained admitted contention, 4 rejecting two new proposed contentions, and terminated 5 the contested hearing. And this is a, just a Gantt 6 timeline of the hearing schedule.
7 This slide illustrates the NRC and 8 reactions related to the ESPA SSAR Section 2.5. The 9 first pre-application audit was held in July of 2015 10 with eight NRC staff and resulted in the 11 identification of 68 issues that require resolution 12 prior to application submittal. In January of 2016, 13 there was a public meeting to discuss the disposition 14 of those issues identified in the readiness 15 assessment.
16 The second audit was held in May of 2017 17 to review geology, seismology, geotechnical 18 information in the application. The audits focused 19 specifically on geological information, vibratory 20 ground motion, and geotechnical engineering 21 information. It included a site, a vicinity tour of 22 geologic features and a review of core samples.
23 This audit identified six specific areas 24 where supplemental information was requested.
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11 1 conducted in January of 2018.
2 I'd like now to introduce the presenters 3 for today's discussion. Wally Justice, who'll be 4 assisted by both Kevin Clahan and Janet Sowers.
5 Wally.
6 MR. JUSTICE: Thank you, Ray. Turn to 7 Slide 8, please. My name is Wally Justice, and I'm a 8 mechanical engineer with 36 years of experience in the 9 United States nuclear industry. In the commercial 10 side, including design, construction, and operation of 11 nuclear power plants. The last several years I had 12 been involved in the small modular reactor technology 13 sector, in addition to working on COLAs and ESPAs.
14 Today I'm going to give you a high level 15 overview of the geological investigations and results 16 provided in early site permit application for the 17 Clinch River site. From the investigations and 18 analysis, you will learn that the only identified 19 geological hazard for the site is karst formations.
20 We will have detailed discussion on the subject later 21 in the presentation.
22 The site directly adjoins the Oak Ridge 23 Reservation, and if you look to the right on the 24 slide, you will see the Clinch River site, bounded by 25 the Clinch River itself as it goes around. It looks NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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12 1 like a small foot.
2 For Section 2.5.1, TVA followed the 3 requirements of 10 CFR 100.23(c). The information 4 was developed in accordance with the NRC guidance 5 documents per Reg Guide 1.206, and NUREG-0800 standard 6 review plans for the review of safety analysis reports 7 for nuclear power plants was followed to produce 8 Section 2.5.1. Next slide, please.
9 The overall geological profile for the 10 Clinch River site area is best explained by 11 understanding of the regional geology and relationship 12 to the eastern United States. A total of six 13 physiographic provinces lie within the 320 kilometer, 14 or 200 mile, radius of the site location. The site is 15 located in the Valley and Ridge Province, with the 16 Appalachian Plateau Province to the west and the Blue 17 Ridge Province to the east. Next slide.
18 Drilling down from the regional view of 19 200 miles to the five-mile site radius from the 20 center, the local ridges and valleys are presented in 21 the figure. The 0.6 mile site location, also known as 22 the one kilometer mile location, is located in the 23 center of the figure.
24 As shown on the 200-mile radius map, the 25 site lies within the regional stratigraphy associated NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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13 1 with the Valley and Ridge Province of folded and 2 faulted carbonate rocks. This consists predominantly 3 of a sequence of Paleozoic sedimentary rocks ranging 4 in age from Lower Cambrian to Pennsylvania, 5 approximately 541 to 323 million years ago.
6 And this slide will reappear in today's 7 presentation in two more instances because it contains 8 useful information related to many of today's topics.
9 This slide represents a one-mile cross-section of the 10 Clinch River site. At the top of the slide, and it 11 may be easier to see on your handouts, but you have 12 Site A, also noted here as, excuse me, Site B, also 13 noted as Location B, and Site, or Location A.
14 We'll be talking today about two faults, 15 the Chestnut Ridge fault and the Copper Creek fault.
16 You will also notice that these are the various rock 17 formations that lie underneath the Clinch River site 18 area. We're on a 33 degree dipping stratigraphy to 19 the southeast, and the borings that are associated 20 with this cross-section are located in their location 21 of drilling, and the depths are presented.
22 CHAIRMAN KIRCHNER: Wally, would you just 23 point out where the CRBR site was relative to A and B.
24 MR. JUSTICE: So I have a slide in a 25 couple slides that will help you understand this a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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14 1 little better, but the old Clinch River Breeder 2 Reactor excavation is actually located in the same 3 rock formation as the Site B. And it would be out 4 from the face of the slide you're looking at. That'll 5 make a little more sense here in just a minute.
6 Now that we have a general idea about the 7 location and the characteristics of the site in 8 region, I would like to discuss some of the methods 9 utilized to investigate and characterize the site, 10 such as field reconnaissance activities.
11 Again, the previous Clinch River Breeder 12 Reactor data and investigations that were done in the 13 late 70s and early 80s, core borings that were 14 performed, reports done for the Oak Ridge National 15 Laboratory, karst mapping, river terrace mapping, just 16 to name a few.
17 The picture to the right is actually a 18 picture of the field investigation for the Copper 19 Creek Cave, which is located approximately five miles 20 from the site center to the northeast. Go to the next 21 slide, please.
22 This slide's a little busy, but it depicts 23 an example of the dates and locations for the field 24 reconnaissance trips to investigate the relevant 25 geological features in the site area. Much of the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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15 1 information I gathered was utilized in subsequent 2 analyses and reports in determining the suitability of 3 the site.
4 MEMBER CORADINI: Are these new, or is 5 this from the original CRBR?
6 MR. JUSTICE: These were performed new.
7 These were performed recently, and if you can see on 8 the slide the dates are actually listed. They're just 9 a little hard to see on the actual chart on the 10 screen. That's okay.
11 We're on Slide 15 now. LiDAR data was 12 taken for the area to ensure complete coverage of the 13 file-mile site area. An example of the results of 14 this effort are located on the right of the slide.
15 The identification of karst depressions, a sink hole, 16 and ground depressions are identified.
17 For example, Figure D, which is at the 18 bottom right corner, shows close depressions that were 19 identified from the LiDAR investigations.
20 MEMBER CORADINI: So remind me, these are 21 surface depressions?
22 MR. JUSTICE: Yes, these would be surface 23 depressions that were identified during the LiDAR 24 investigation.
25 Okay, this is the core borings for the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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16 1 Clinch River Breeder Reactor Project. Again, that was 2 in the late 70s and early 80s. And I wanted to 3 present this. It's very busy and hard to read, but 4 you can see this area of a lot of borings. That's the 5 actual excavation area for the Clinch River Breeder 6 Reactor.
7 If we go to the next slide, this shows 8 right here is the old Clinch River Breeder Reactor 9 footprint. So it is outlined in blue on your slide.
10 Then there's a series of new cores that were performed 11 associated with the current Small Modular Reactor 12 Project. Site B is generally located in the red 13 circle, as is Site A.
14 And just to help understand the number of 15 borings, 76 rock core borings were performed for the 16 Small Modular Reactor Project in present day. And 17 there were 104 borings that were performed for the 18 original Clinch River Breeder Reactor Project. All of 19 this information was utilized to help us characterize 20 the site for this early site permit application.
21 MEMBER RAY: Was there any difference in 22 the information provided by the two eras and types of 23 boring used and so on?
24 MR. JUSTICE: In general, they were very 25 close in agreement with, from one era to the next.
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17 1 MEMBER RAY: So you didn't have some new 2 technology that enabled you to get more information 3 now than in the past?
4 MEMBER CORADINI: I think he was talking 5 about old versus new, not A versus B.
6 MEMBER RAY: No, that's right, yeah.
7 MR. JUSTICE: That's correct. I 8 understand the question you're asking is the old 9 borings that were performed in the late 70s to support 10 the Breeder, and then the borings that were performed 11 in modern day, today, was there anything, any 12 different or significant from those. And the answer 13 to that is no.
14 MEMBER RAY: Thank you.
15 MR. JUSTICE: I would now like to turn --
16 CHAIRMAN KIRCHNER: Wally, before you go 17 on, just --
18 MR. JUSTICE: Yes, sir.
19 CHAIRMAN KIRCHNER: I can't read it here.
20 What's the distance between the center of B and A?
21 MR. JUSTICE: The center, the distance 22 between B and A is approximately 600 feet.
23 CHAIRMAN KIRCHNER: Six hundred feet, 24 okay. Two football fields. Is there a preferred site 25 between A or B, or you were just covering all bets?
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18 1 MR. JUSTICE: For the application, we 2 evaluated two specific locations on the site, 3 specifically because you'll learn that these are in 4 different rock members from a geologic perspective.
5 Based on the technology that TVA may decide to select, 6 you may need more than one location to build one or 7 more plants. So it was decided to do two locations, 8 and at this time there's really not a preferred 9 location associated ---
10 (Simultaneous Speaking.)
11 CHAIRMAN KIRCHNER: So there isn't at this 12 point.
13 MR. JUSTICE: That's correct.
14 CHAIRMAN KIRCHNER: Thank you.
15 MR. JUSTICE: So I would now like to turn, 16 or excuse me, to introduce Kevin Clahan from Lettis 17 Consultants International to discuss faults and sheer 18 fracture zones for the next few slides. Kevin.
19 MR. CLAHAN: All right, thank you, Wally.
20 It's nice to be here. My name is Kevin Clahan and I'm 21 a professional geologist and certified engineering 22 geologist with over 25 years of experience conducting 23 geologic and seismic hazard studies around the world.
24 I've worked for over 12 years now in the nuclear 25 industry evaluating conditions at 11 different NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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19 1 proposed or existing nuclear sites, and I've been 2 working on the Clinch River site since 2011.
3 This slide here, can I borrow a pen?
4 Thank you. So faults are one of the more important 5 aspects of any site evaluation, and the assessment of 6 that faulting. The first step in this evaluation is 7 understanding the bedrock and Quaternary geology.
8 And so what you see here at the latitude 9 of the Clinch River site, we have a repeated section 10 of interbedded carbonate and shale units that are part 11 of the Rome. You can maybe see better on, oops. The 12 Rome, Conasauga, Knox, and Chickamauga group.
13 And so you'll see those same patterns 14 here. We have a light tan, green, brown, pink that 15 are repeating. At the boundary of these repeating 16 sections are large scale thrust faults that were 17 active during the late Paleozoic Alleghanian orogeny, 18 which occurred some 320 to 280 million years ago.
19 And you're going to be hearing the term 20 Alleghanian orogeny, so I just want you to understand 21 that that was the orogeny where the plates Gondwana 22 and Laurentia collided to form Pangaea and close the 23 proto-Atlantic Ocean before it reopened again. So 24 that happened about 300 million years ago.
25 MEMBER CORADINI: No test, right?
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20 1 MR. CLAHAN: There's no test after this.
2 So we know that these faults have not become active or 3 have been active in the last 276 million years, and 4 that's due to fault gouge dating by argon-argon on the 5 Copper Creek fault, just to the north, several miles 6 to the north of the site here.
7 As well as a well-studied dyke system that 8 was emplaced within the Valley and Ridge formation, 9 which offsets these faults. And that dyke system was 10 dated at about 200 million years, so that gives you a 11 minimum age at least for the activity of that 12 faulting.
13 In addition, what we did is we've mapped 14 Quaternary river terraces upstream and downstream of 15 the site along the Clinch River within the five-mile 16 site radius. So we mapped from approximately here all 17 along up to here, and mapped Quaternary fluvial 18 terraces, plotted those terraces. And then where they 19 projected across these particular faults, looked for 20 any sort of deformation.
21 Some of these river terraces are on the 22 order of several hundred thousand years old, and we 23 saw no deformation associated with those terraces due 24 to those faults. All right, next slide, please.
25 So while we're on the topic of faulting, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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21 1 a potentially related feature was described during the 2 excavation of the Breeder Reactor. They referred to 3 this particular feature as a shear zone, and we 4 identified this same feature in our bore hole 5 investigation. The two images here are a cross-6 section similar to what Wally showed early, our 7 dipping stratigraphic units.
8 The shear zone, or shear fracture zone as 9 we're referring to it, is in yellow here. And we 10 found it in two locations, and it projects parallel to 11 bedding and with the same dip as well.
12 The shear fracture zone itself, again, is 13 a bedding parallel feature that's characterized by an 14 abundance of calcite veins, stylolites, which are a 15 result of pressure solution. These are oriented both 16 parallel and perpendicular to bedding, as well as some 17 slick insided fractures.
18 And what this image on the bottom right is 19 trying to do, and it's difficult to see, but on your 20 handouts, we give examples of those particular 21 features. These black serrated lines here are 22 parallel to bedding stylolites, the white blebs are 23 veins, and then we have some normal, or perpendicular 24 to bedding stylolites as well here. And we'll see 25 some more of that on the next slide as well.
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22 1 Before we go to the next slide, let's see, 2 I want to mention that these features sometimes 3 truncate each other in ways which support a diagenetic 4 or syndepositional origin, meaning they occurred 5 during deposition and lithification of the rock. And 6 this rock, again, is the Chickamauga group, it's on 7 the order of 500 million years old.
8 When we see stylolites that are oriented 9 perpendicular to bedding, we associate that with the 10 tectonic overprinting, which I'll show you in the next 11 slide. Again, there's no measurable displacement 12 along this zone, and it is not visible in the ground 13 surface. Okay, next -- oh, and I want to conclude 14 that by saying the breeder reactor PSAR concluded that 15 this feature is a zone of interbed slippage that 16 occurred during the Alleghanian orogeny.
17 MEMBER CORADINI: So may we have a minute 18 for digression?
19 MR. CLAHAN: Yeah.
20 MEMBER CORADINI: You said there's no 21 displacement, so how are you measuring displacement?
22 Because you're looking a long time ago.
23 MR. CLAHAN: Yes.
24 MEMBER CORADINI: So displacement means 25 that I'm looking for a difference in the qualitative NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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23 1 features of the rock? I'm --
2 MR. CLAHAN: That's right. No, that's 3 right. If there was a fault, you would see a 4 discernable displacement of like units on either side 5 of that particular feature. Here, we don't see any 6 discernable offset. There's minor microfracturing of 7 things, there's vein, there's pressure dissolution, 8 which sort of skews the margins of contacts, but 9 there's no through going deformation or displacement.
10 MEMBER CORADINI: But more generally since 11 you're going, I'm going to, you're going to lose me, 12 is it more of a qualitative judgement on your part to 13 look for something?
14 MR. CLAHAN: No --
15 MEMBER CORADINI: In other words, if I see 16 a fracture or if I see an opening, the measurement of 17 the opening is not important as much as there's 18 physically an opening that you see of like rock.
19 MR. CLAHAN: Not necessarily. When you're 20 looking at whether or not there's active faulting or 21 there's faulting in a general area, you're looking for 22 that displacement. So the fracturing and the 23 separation of rock could be completely, something 24 completely different.
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24 1 push the point. So now I see a fracture, so how do I 2 know how old it is? It could be a fracture from 100 3 million years ago, 200 million years ago.
4 MR. CLAHAN: Sure.
5 MEMBER CORADINI: Twenty years ago.
6 MR. CLAHAN: It's a good question, yeah, 7 good question. And what that ties into are these 8 stylolites, and these are a result in carbonate rock 9 of dissolution during deposition. And we also see a 10 imprint of a tectonic. And so what we're doing is 11 correlating the two different phases of stylolite 12 formation with the deposition of the rock 500 million 13 years ago, and then the Alleghanian orogeny 280 14 million years ago.
15 And so all that deformation occurred 16 within that window. Does that answer?
17 MEMBER CORADINI: Yeah.
18 MR. CLAHAN: So we can tell that age.
19 MEMBER CORADINI: The age of the fracture.
20 MR. CLAHAN: That's right.
21 MEMBER CORADINI: Okay.
22 MR. CLAHAN: Yeah, that's right.
23 CHAIRMAN KIRCHNER: Also, Kevin, so the 24 picture on the left is the depth of the bore holes and 25 the picture on the right has a scale of about two or NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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25 1 three feet.
2 MR. CLAHAN: That's right.
3 CHAIRMAN KIRCHNER: All right, so what 4 we'll see on the right is coming up on the next slide.
5 MR. CLAHAN: It is, that's right.
6 CHAIRMAN KIRCHNER: That's fine, okay.
7 MR. CLAHAN: Yes, and this is a schematic 8 --
9 CHAIRMAN KIRCHNER: Connective pieces.
10 MR. CLAHAN: This is part of one of the 11 RAIs that we helped, sort of explained the shear 12 fracture zone. So next slide, please. So these 13 images show photographs of natural and modified logs 14 that are detailing the shear fracture zone features.
15 And one thing to notice again is the abundant veining 16 compared to the adjacent rock. You see that in 17 certain areas here.
18 The serrated stylolites produced by 19 pressure solution, both parallel to bedding and 20 perpendicular to bedding. Down here, the stylolites 21 are listed as in purple, bedding is in yellow on this 22 figure. So bedding again here, you can see this is a 23 33 degree southwest dipping bedding, represented in 24 the core. And then these are those bedding parallel 25 stylolites that formed during syndeposition of that NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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26 1 rock and lithification of that rock.
2 We also see stylolites that are 3 perpendicular to the bedding here. And those give us 4 an idea that those subvertical stylolites indicate 5 pressure solution occurred during subhorizontal 6 compression, which coincides with the shortening and 7 emplacement of the Valley and Ridge thrust faults 8 during the Alleghanian orogeny.
9 There's a lack of brittle cataclasis or 10 fault brecchi or gouge that we see associated with the 11 Copper Creek fault, which we know to have accommodated 12 at least 50 kilometers or so of shortening. All the 13 faults within the Valley and Ridge have accommodated 14 together approximately 250 kilometers of shortening 15 during the Alleghanian orogeny. That's going to be on 16 the test.
17 So again, these parallel stylolites 18 occurred during bedrock formation, and they're also 19 located throughout all the cores. All right, and so 20 these features, again, are not fault-related, but they 21 accommodate internal deformation of the rock and they 22 show no discernable displacement.
23 And that's all I have. I'd like to turn 24 it back to Walt.
25 MR. JUSTICE: Thank you, Kevin. Next NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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27 1 slide, please.
2 Local geological hazards. NUREG-0800 3 requires the identification of geological hazards 4 which may affect the suitability of a site for the 5 construction of a nuclear power plant. As I stated 6 earlier, through our investigations, karst dissolution 7 is the primary geologic hazard of concern for this 8 application.
9 Janet Sowers, who is also to my right and 10 pictured in the picture on the slide, will now take up 11 the discussion of the topic. Janet, would you please 12 introduce yourself.
13 MS. SOWERS: Thank you, Wally. My name is 14 Janet Sowers and I'm a licensed professional geologist 15 with Fugro. I received an undergraduate degree from 16 University of Virginia and a PhD from University of 17 California. During my 30-year career, I've worked on 18 site characterization and geologic hazard projects for 19 many large infrastructure projects, including six 20 proposed or existing nuclear power projects.
21 One of my specialties and my focus for the 22 Clinch River Project is the karst characterization and 23 evaluation of karst hazards. Next slide.
24 So karst is a landscape with distinctive 25 features that are formed by the slow dissolution of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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28 1 limestone by groundwater. The water flows through the 2 fractures and joints, enlarging them and eventually 3 forming an underground drainage system, and karst 4 landscape features such as sinkholes and caves and 5 springs and an irregular bedrock contact underneath 6 the soil.
7 This is an example of a karst model drawn 8 for an area, the Copper Ridge area of Oak Ridge, where 9 the, it's underlined by thick dolomite. The rock 10 under the hillside has a number of dissolution 11 passages shown by yellow, in yellow. Many were formed 12 when the rock was under the groundwater table in the 13 phreatic zone.
14 After the erosion cut down and drained 15 these passages, vadose zone dissolution, or 16 dissolution above the water table, took place by 17 descending rainwater forming vertical slots and steep 18 passages, which may intersect the older phreatic 19 passages.
20 Sinkholes form at the ground surface, 21 typically where the soil over the bedrock filters down 22 into the underground slots and passages, and then 23 undermines the surface soil. And the surface soil 24 then sinks or collapses to form the sinkhole. It's 25 called a cover collapse sinkhole, and that's the most NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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29 1 common type of sinkhole in the Valley and Ridge.
2 Springs occur where conduits discharge at 3 the surface. In a later slide we'll show you a karst 4 model that we've developed for the Clinch River site.
5 This particular karst model was developed by the 6 Tennessee Geologic Survey for the Copper Ridge area.
7 Next slide.
8 MEMBER CORADINI: So just a cartoon, since 9 we have the cartoon in front, so this is mainly by 10 rainfall moving its way through the earth to the 11 river, versus river intrusion subsurface? Or some 12 combination of that?
13 MS. SOWERS: Let's back up for just a 14 second, because many of the passages are phreatic, 15 which means they were formed below the water table.
16 Right now, they're high and dry in this model. So 17 imagine, undo the downcutting of the Clinch River and 18 put a lot more rock back up on top.
19 And then you're under the groundwater 20 table, and rainwater then descends down through, and 21 then there's groundwater circulation underneath the 22 water table that is dissolving out these phreatic 23 passages.
24 MEMBER CORADINI: And so this all natural.
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30 1 --
2 MS. SOWERS: No, no mining operations.
3 And this is a very slow process.
4 MEMBER CORADINI: Okay.
5 MS. SOWERS: All right, so next one. We 6 based our karst analysis on information from previous 7 --
8 CHAIRMAN KIRCHNER: You said that, Janet, 9 it was slow. Just for the record, how slow?
10 MS. SOWERS: How slow? It's slow enough 11 that you would not notice dissolution in your lifetime 12 or in the lifetime of the planet. We would not notice 13 it. It's like in the order of centimeters per hundred 14 or thousand years.
15 CHAIRMAN KIRCHNER: So if we do a good 16 mapping of the potential site, then for the lifetime 17 of the power plant, we would not expect one of the 18 sinkholes to form.
19 MS. SOWERS: We would not expect 20 additional rock dissolution that we could notice.
21 Sinkholes are more of a surface phenomenon that 22 involves the soil.
23 CHAIRMAN KIRCHNER: Yeah I know --
24 MS. SOWERS: So you could get, you can get 25 sinkholes from, in the soil, during the lifetime of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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31 1 the plant.
2 MEMBER CORADINI: But to get to Walt's 3 point, you've got to, once you know the shape of the 4 geometrically.
5 MS. SOWERS: In the rock.
6 MEMBER CORADINI: You're going to be 7 around essentially static during the life of this --
8 MS. SOWERS: Yes, the rock passages will 9 be --
10 MEMBER CORADINI: Project.
11 MS. SOWERS: For the lifetime of the plant 12 will be, we would consider static. Thank you for the 13 question.
14 So we're basing our analysis on existing 15 and new information that we develop for the project.
16 There were many karst studies that were done at Oak 17 Ridge on the Reservation, including an inventory of 18 karst features and a number of groundwater studies 19 that tracked flow of groundwater through karst 20 passages.
21 We also looked at the Clinch River Breeder 22 Reactor data from the 1970s and 1980s. This provided 23 good topographic mapping of the site before 24 development, so we could see locations of sinkholes 25 and what the original ridges and valleys looked like.
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32 1 We also were able to use the detailed logging that 2 they did of the cavities encountered in bore holes and 3 incorporate that in with our bore hole data.
4 For this SMR project, we conducted a LiDAR 5 mapping of karst features from the five-mile radius, 6 which Wally showed you some examples from. And then 7 we compiled all the core boring information from the 8 breeder reactor and the SMR project for analysis and 9 modeling. Next slide.
10 Here are the conclusions. I'm sorry 11 that's such a small font, we had intended to cut out 12 some of this. The first bullet really says that the 13 flow in our site is strike parallel, meaning the 14 orientation of passages goes along strike, so 15 perpendicular to the direction of the dip.
16 And the reason that we have that at our 17 site is that the Chickamauga Group is a interbedded 18 sequence of limestones and silt stones and silty 19 limestones. And dissolution is more well developed in 20 the pure limestones, so that the orientation of karst 21 development is parallel to strike along those more 22 pure limestone beds and units.
23 Second bullet says that there are some low 24 carbonate units, and they are generally silt stones.
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33 1 Reactor was built, and that would be for Site B. We 2 also have the Blackford formation and the Bowen 3 formation. Those are also more carbonate pure, and 4 those units have no mapped sinkholes. And they have 5 smaller and fewer bore hole cavities than the other 6 units.
7 The third bullet says that based on the 8 bore hole data, the frequency and size of cavities, 9 generally these decreases with depth as you go down.
10 It doesn't, we don't completely run out of cavities.
11 There still are some in our deepest bore holes, but 12 they're smaller. But they're there, so there are 13 cavities beneath the water table. But in generally 14 it's more of a surface-intensive process where we have 15 the greater sizes and frequency of cavities closer to 16 the ground surface.
17 The third bullet makes a point about 18 hypogene dissolution, which we haven't introduced yet, 19 but just to let you know. Epigenetic dissolution 20 means that the water, rainwater comes down, it 21 dissolves from the vadose zone, it forms the 22 groundwater and dissolves in the phreatic zone.
23 Hypogene dissolution would be water 24 welling up from depths below, where it may be warm, it 25 may be super-charged with minerals. And that can NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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34 1 often be a more aggressive dissolution and is 2 documented in other parts of the Valley and Ridge, 3 such as in Virginia, but not at our Clinch River site.
4 MEMBER CORADINI: Is that, you can tell 5 that by the chemical content of the water?
6 MS. SOWERS: You can tell it by the 7 chemistry of the water, by deposition of exotic 8 minerals in around springs, and by the temperature of 9 the water.
10 MEMBER CORADINI: Okay. So no possibility 11 --
12 MS. SOWERS: No, we don't, no. Everything 13 seems to have a meteoric signature, all the rainwater.
14 I mean, all the spring water.
15 CHAIRMAN KIRCHNER: So Janet, since it's 16 up there, would you just explain one more time for the 17 quiz, phreatic versus --
18 MS. SOWERS: Vadose?
19 CHAIRMAN KIRCHNER: Where is the other?
20 MS. SOWERS: Phreatic is at and below the 21 water table, the groundwater table. Vadose is in the 22 unsaturated zone above. So in the vadose zone, water 23 is generally descending along fractures, joints, 24 bedding plains. In the phreatic zone, it's moving 25 along whatever paths it can find.
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35 1 MEMBER CHU: Can I ask you a question?
2 You, I think you said the karst located below 3 groundwater level, am I correct or not?
4 MS. SOWERS: Karst is, happens both above 5 and below.
6 MEMBER CHU: Above, okay. What is the 7 most, what do you see that's closest to the surface, 8 the location of the karst from your mapping?
9 MS. SOWERS: The sinkholes are the most, 10 are the surficial expression of karst processes 11 happening at depth. Sinkholes is the number one thing 12 that we see at the surface. Springs, cave entrances, 13 those are also things that you see at the ground 14 surface. And those are things that we were mapping 15 with the LiDAR.
16 MEMBER CHU: Okay.
17 MS. SOWERS: Okay, next slide. All right, 18 as promised, here is our karst model for our site.
19 MEMBER CORADINI: Let me just ask another 20 question. So if you know have mapped where the holes 21 are, and you now have Site A and B and you're going to 22 dig through it to put down a foundation for a 23 installation, do you fill the holes, or just monitor 24 that they're small enough that you ignore 25 structurally, or is that not your problem?
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36 1 MS. SOWERS: We'll be discussing that --
2 MEMBER CORADINI: Later?
3 MS. SOWERS: In the, near the end when we 4 talk about geotechnical engineering. But good 5 question.
6 So here's our model, and it's a cross-7 section of the site, similar to what you saw before.
8 It's a little bit more artistic, we tried to show what 9 the bedrock, the rock types actually are. So going 10 from the west to the east, the, here's the dolomite.
11 And this is the Knox Group. We are not going to be 12 building on this, this is at the northern part of the 13 property, however.
14 And the Knox Group, like the Copper Ridge 15 dolomite, is more intensely karstified than these 16 other units. So we're representing the cavities with 17 the black. Of course, it's a schematic, so nothing is 18 implied here as far as actual locations. This is a 19 schematic of how we think it might look.
20 There's the Knox Group, there's an 21 unconformity between them. There was a period of 22 erosion of the Knox before the Chickamauga was laid 23 down. So here's the Chickamauga from here over to the 24 Copper Creek fault over there, and our sequence of 25 beds.
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37 1 This is the siltstone, the Fleanor 2 formation, on which the Breeder Reactor was excavated, 3 and this is the location for our Location B. Our 4 Location A will be over here, and one of the limestone 5 units, it's one of the siltier ones, but it is a 6 limestone unit, Location A, right here.
7 So we tried to show that there are 8 cavities generally follow bedding plains and joints, 9 and large bedding planes and joints, and that there 10 are more near the surface and there are still some 11 down at depth as well. On the other side of the 12 fault, in the Rome formation, that's a sandstone. So 13 that is not a karst unit.
14 And with that, I will turn it back over to 15 Wally.
16 MR. JUSTICE: Thank you, Janet. Next 17 slide, please.
18 We have discussed the Clinch River Breeder 19 Reactor Project in this presentation, and this 20 photograph is the completed excavation in 1983. The 21 documented geological mapping of the excavation has 22 been very helpful in our current site characterization 23 efforts. This excavation is also located, as Janet 24 said, in the same rock member, the Fleanor, as Site B 25 that we are discussing today and in the application.
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38 1 Karst features identified during the 2 excavation of the Clinch River Breeder Reactor were 3 considered small and manageable, particularly 4 supporting the conclusion that karst cavities are 5 reduced in size and frequency as depth is increased.
6 Just for your information, this excavation was 7 approximately 483 feet long by 360 feet wide, about 8 100 feet deep.
9 And if you look at the picture, this rock 10 unit here is the Rockdell unit. This unit here is the 11 Fleanor unit, and the basement of the excavation lied 12 within the Fleanor unit. So this mapping that was 13 performed, it was documented in some regulatory 14 documents and some supporting reports. And again, 15 during that excavation, they did not identify any 16 large karst cavities as part of their mapping efforts.
17 Next slide, please.
18 So in conclusion, for SSAR 2.5.1, active 19 faulting is not a geological hazard for site area or 20 the region. All identified faults are considered 21 greater than 290 million years old. Shear fractures 22 are not a geological hazard for the site area, as they 23 are also greater than 290 million years old.
24 Karst conditions are identified as the 25 potential geological hazard for the area, and the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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39 1 information to discuss how we will identify and 2 mitigate in the future will be discussed in the 3 following presentation. And we believe we've met the 4 regulatory requirements of 10 CFR 52.17 and the 5 guidance from Regulatory Guide 1.2.08.
6 I'll now take us to the second portion of 7 the presentation, which is discussion on SSAR Section 8 2.5.2, seismology. I have Ivan Wong from Lettis 9 Consultants International on the bridge line in the 10 event that I have a question that needs a technical 11 answer from him, but I will start the presentation.
12 2.5.2 is there to determine the site-13 specific ground motion response vector, the GMRS. The 14 GMRS is identified as a free filled horizontal and 15 vertical ground motion response spectrum at the site, 16 and it must satisfy the requirements of 10 CFR 100.23.
17 We developed the GMRS in accordance with 18 NUREG-0800, we also developed the ground motions in 19 the SSAR with implementation of the provisions in Reg 20 Guide 1.208, the performance-based approach to define 21 the site-specific earthquake. Next slide, please.
22 This is a plot of the Central Eastern 23 United States Earthquake Catalog, showing the location 24 and magnitudes of seismic activity in the central and 25 eastern United States. This information is contained NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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40 1 in NUREG-2115, the central eastern United States 2 seismic source characterization for nuclear 3 facilities. Next slide, please.
4 Within that zone, the East Tennessee 5 Seismic Zone is defined as an area of more frequent 6 seismic activity, although this activity is relatively 7 small in magnitude. The source is specifically 8 detailed in NUREG-2115 and captures the current 9 understanding of the seismic hazard.
10 It should be noted that TVA has two plants 11 operating within the current East Tennessee Seismic 12 Zone, the Watts Bar Nuclear Plant, located 13 approximately there, and the Sequoyah Nuclear Plant, 14 which is located approximately in that location. Next 15 slide, please.
16 I'm sorry, the Clinch River is that red 17 arrow or red star. Just slightly outside of the 18 Eastern Tennessee Seismic Zone.
19 MEMBER RICCARDELLA: Okay, thank you.
20 MR. JUSTICE: Next slide, please. For the 21 ground motion response development approach, this is 22 a very high level description of how information is 23 utilized to develop the GMRS for the Clinch River 24 site.
25 The rock hazard is a result of the site-NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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41 1 specific probabilistic seismic hazard analysis, which 2 used an updated Department of Energy, EPRI, NRC, CUS 3 seismic source characterization models in the EPRI 4 ground motion models. This is now the standard 5 practice for seismic analysis post-Fukushima. Next 6 slide, please.
7 I would like to just a brief overview of 8 the method we used out of Reg Guide 1.208, which is 9 known as Approach 3. It is fully probabilistic, it 10 preserves hazard levels. The hazard at the surface is 11 computed by integration of the hard rock hazard with 12 the probability distribution and frequency, and this 13 results in a complete hazard curve at the ground 14 surface.
15 It is endorsed by NUREG-6728. And the 16 basic steps in Approach 3 are the randomization of 17 site-dynamic material properties, the computation of 18 amplification factors using random vibration theory, 19 and the full integration of mean and fractal hazard 20 curves. Next slide, please.
21 This slide I had a presented a couple of 22 times earlier today, but I just wanted to point out 23 again Site A, excuse me, Site B and Site A locations.
24 We've talked about the faults on both ends, we talked 25 about the dipping angle. This is a one-mile NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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42 1 representation. I would like to go to the next slide.
2 And this is a four-mile representation, 3 which includes the Clinch River site, which is the 4 purple box. It has the Site B profile, which is this 5 purple location, and the Site A profile. So this a 6 much larger map, and it is also to basement depth of 7 approximately 12,000 feet below sea level. So this 8 shows all of the rock units that are associated with 9 it, and it shows their relative velocities.
10 And I believe, if you'll pardon me, I just 11 cannot see that number. So we see that the limestone 12 is approximately 10,500 feet per second. And the 13 shale, the Conasauga shale, is approximately 6,000 14 feet per second. The limestone, the Chickamauga, is 15 also approximately 10,000 feet per second. Next 16 slide, please.
17 Profiles were developed for both Sites A 18 and B separately, based on the velocity shown on the 19 cross-section you just saw, based on the particular 20 rock members and depth. And if you compare these two, 21 even though they're in different rock members, you 22 notice that there's a lot of consistency in the 23 profiles. Next slide, please.
24 The mean rock hazard curves were then 25 developed based on that analysis. And this is the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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43 1 hazard at ground surface for the Clinch River site, an 2 example. Next slide.
3 We then, from that information, developed 4 the ground motion response specter for Site A and Site 5 B. And then if you go the next slide. We then 6 brought those two curves together and combined them 7 into one overall, enveloping ground motion response 8 specter for the Clinch River site. This is for both 9 the horizontal and vertical ground motion response 10 specter. Next slide.
11 The 2D sensitivity analysis was performed 12 to determine if the dipping stratigraphy of 13 approximately 33 degrees was fully recognized by the 14 1D analysis or the GMRS analysis. The 2D analysis is 15 considered a multi-dimensional approach for validation 16 for Reg Guide 1.208.
17 The 2D-1D comparison described in the SSAR 18 and documented in the GMRS study involved calculating 19 the amplification for the full, two-dimensional 20 profile compared to amplification of single, one-21 dimensional profiles as best estimate slices through 22 the midpoint of Sites A and B.
23 In the site response analysis performed to 24 develop the GMRS, the best estimate 1D profiles at 25 Sites A and B were used along with upper and lower NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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44 1 wrench profiles at each location for a total of six 2 profiles and associated amplification factors.
3 The hazard was then calculated for each of 4 the six profiles, and the hazard at Sites A and B each 5 reflecting a wave average over best estimate and upper 6 and lower wrench profiles. Next slide.
7 MEMBER CORADINI: Can you go back to the 8 angle?
9 MR. JUSTICE: Back one more?
10 MEMBER CORADINI: I'm just trying to 11 understand what was done, so maybe Slide 36? That 12 one. So the 1D basically layers them horizontally?
13 Not vertically, I assume. So when you say it's a 1D 14 model, I basically take all these various rock 15 formations with different sound speeds and just layer 16 them one on top of the other.
17 MR. JUSTICE: That is correct.
18 MEMBER CORADINI: Okay. And the two 19 dimensional actually captures in two dimensions the 20 angle or feature, the angle.
21 MR. JUSTICE: Correct. And then you 22 perform a comparison to see if the assumptions that 23 were performed in the 1D were fully captured, based on 24 the 2D analysis.
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45 1 back to 40?
2 MR. JUSTICE: Slide 40?
3 MEMBER CORADINI: Yeah. So the dark blue 4 at the bottom is 2D, everything else is 1D above it.
5 MR. JUSTICE: That's correct.
6 MEMBER CORADINI: And on the Y axis is 7 what?
8 MR. JUSTICE: The side amplification.
9 MEMBER CORADINI: What does that mean?
10 Can you help me there? So it's the G force times that 11 number?
12 MR. JUSTICE: So at this frequency, this 13 is the amplification factor associated with each 14 frequency from the analysis.
15 MEMBER RICCARDELLA: A single degree of 16 freedom oscillator at the --
17 MEMBER CORADINI: You need to turn 18 something on. Higher.
19 MEMBER RICCARDELLA: A single degree of 20 freedom oscillator at the frequency, right? And so 21 when the two dimensional you do, you look at the 22 vertical as well as the horizontal, is that the two 23 dimensions?
24 MR. JUSTICE: That's correct. And you 25 have, and we had a slight accedence at approximately NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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46 1 two, frequency of two hertz in both cases. But that 2 was the only place that there was any accedence 3 associated with 2D sensitivity.
4 MEMBER RAY: I think Mike's asking 5 amplification of what.
6 CHAIRMAN KIRCHNER: Ground motion.
7 MEMBER CORADINI: And so I've got at some 8 depth a wiggle, and I'm wiggling it at some frequency.
9 And then I'm looking at the surface, what that wiggle 10 corresponds to after it's passed through all these 11 layers of stuff.
12 MR. JUSTICE: That is correct.
13 MEMBER CORADINI: Okay, so is this, it's 14 got to be horizontal wiggle, it can't be side to side 15 wiggling, because one dimensionally, it doesn't --
16 MR. CLAHAN: It's vertically propagating 17 shear waves.
18 MEMBER CORADINI: But the shear wave is a 19 vertical propagating shear wave, so it's not, it's 20 horizontal motion. It's vertical motion, vertical 21 motion. It can't be horizontal motion, not with a 1D 22 modeling.
23 MEMBER RAY: Mike, there's two dimensions 24 in the horizontal plane.
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47 1 1D model where they're levering rock this way, so I 2 can't do anything here and model that. I'm only 3 modeling wiggling that way.
4 MEMBER RAY: How much shear in the one 5 direction? You're talking about -- yeah, yeah.
6 MEMBER CORADINI: So there's some sort of 7 shear component perpendicular to the oscillation 8 that's modeled in the 1D model.
9 MR. JUSTICE: So perhaps it would be best 10 if we brought Ivan Wong from Lettis on the bridge 11 line.
12 MEMBER CORADINI: I just want to 13 understand all the curves. At least, so I understand 14 it vertically, how you did the layering. I just was 15 trying to understand the side-to-side horizontal 16 motion.
17 MR. JUSTICE: We'll see if we can get you 18 a little better explanation than I'm going to be able 19 to give you on this subject. Is the bridge open where 20 Ivan can hear me?
21 MR. WONG: Wally, I'm on the line.
22 MR. JUSTICE: Hello, Ivan. If you would 23 be so kind as to give your background and experience 24 and your full name, and we'll answer the question.
25 MR. WONG: Okay. My name is Ivan Wong, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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48 1 I'm a seismologist with Lettis Consultants 2 International. I have 44 years of experience in 3 seismic hazard, and I guess my most conspicuous 4 project was I was the Project Manager for the seismic 5 hazard evaluation of the Yucca Mountain Project for 6 about 15 years.
7 So Wally, are we looking at the slide 8 that's a comparison of 1D and 2D amplification 9 factors?
10 MR. JUSTICE: That is correct, we're on 11 Slide 40.
12 MR. WONG: Okay, so what we're showing 13 here is the results of basically a 1D and 2D site 14 response analysis. So we're basically showing what we 15 call amplification factors, which compare the ground 16 motions at the input of a soil column, versus anywhere 17 at the top of the column.
18 So in the 1D analysis, as one of the 19 members of the Committee mentioned, in a 1D analysis 20 it's a, basically a layer cake profile. We're 21 modeling vertically incident seismic shear waves, so 22 they're vertically propagating, they go up through the 23 column in a vertical fashion.
24 But because they are shear waves, the 25 particle motion is horizontal. So we're looking at NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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49 1 the horizontal motion from a vertically propagating 2 shear wave velocity.
3 So in the 2D, we're actually modeling the 4 dipping stratigraphy and just calculation the 5 amplification factors of the vertically propagating 6 through the dipping layers. And in that figure, we're 7 just comparing the amplification factors between the 8 1D and the 2D.
9 And as Wally has stated, the 1D 10 amplification factors are conservative. But to the 11 2D, and that's simply because when we did the 1D, we 12 had multiple profiles and we included all the 13 uncertainties. And so that compensates for any 2D 14 effects.
15 And the other observation is because the 16 velocities of the rock are so hard, the 2D effects are 17 very, very small. So it's easily captured in the 1D 18 analysis.
19 MEMBER CORADINI: So just one last 20 question, just so I think I get it. So there's a 21 frictional, there's an assumption of frictional 22 between the layer cakes? In other words, if I start 23 wiggling it horizontally, which you call a shear wave, 24 one made up of layer X then provides a force to layer 25 Y.
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50 1 But there must be a shear component at the 2 interface between the two layers, which is the same 3 assumed in both analyses?
4 MR. WONG: There is that particle motion, 5 or friction as you call it. But again the velocities, 6 because the rock is so hard, even though you're going 7 from one rock type to another, let's say from 6,000 8 meters per second to 10,000 meters per second, that 9 transfer of motion is relatively small.
10 If you were in lower velocity materials, 11 like a soil, where the velocities are on the more, on 12 the order of a few hundred meters per second, that 13 effect that you're talking about would be more 14 pronounced. But there it's not.
15 MEMBER CORADINI: Okay, so really what 16 we're seeing between the blue line, which is lower in 17 all the other colored lines, is the effect of the 18 angle or structure.
19 MR. WONG: Yes.
20 MEMBER CORADINI: Got it, thank you.
21 MR. WONG: Absolutely, thank you.
22 MEMBER RICCARDELLA: So, yes, another 23 question. So in the 2D model, are you still putting 24 in a single, one dimensional horizontal movement that 25 just, and you're just considering the stiffness in the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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51 1 two different directions, that they? Or are you 2 looking at two different, distinct directions of 3 vibratory motion, vertical and horizontal?
4 MR. WONG: No, we're still putting in, 5 we're still putting in, you know, vertically 6 propagating waves. But they, we're looking at the 2D, 7 yeah.
8 MEMBER RICCARDELLA: Yeah.
9 MR. WONG: So we're looking at them in the 10 two dimensional sense. And we're propagating them 11 through that 2D structure.
12 MEMBER CORADINI: But the source term is 13 the same. I thought what was Pete was asking, the 14 source is the same. It's still --
15 MEMBER RICCARDELLA: The driving 16 vibration, you're just putting in horizontal motion, 17 at various frequencies, right?
18 MR. WONG: Yes, absolutely.
19 MEMBER RICCARDELLA: Okay, thank you.
20 MR. JUSTICE: Thank you, Ivan.
21 MEMBER SUNSERI: So I have a question.
22 Maybe you're leading us to this answering my question, 23 and if so I can be patient and wait. But if I think 24 about the previous presentation with the karst, and I 25 would characterize that as blemishes near the surface, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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52 1 such as streams, caves, sinkholes, etc., and then I 2 think about the proximity of the site to this Eastern 3 Tennessee Seismic Zone, is it possible that the 4 seismic activity could connect perforations, like 5 peeling the postage stamp off the perforated sheet and 6 cause problems that way?
7 I'm just trying to think of where this 8 presentation's going to end up, what the conclusion's 9 going to be. You understand what I'm saying?
10 So you have the karst, which at least what 11 I'm hearing described is blemishes near the surface, 12 or it could be anywhere, but I'm talking about the 13 ones near the surface, the caves, the streams, the 14 sinkholes, whatever. They're randomly distributed, I 15 presume. And you have the site, and then the site is 16 adjacent to this Eastern Tennessee seismic area.
17 So now you have something seismically 18 happen. Can you connect the blemishes and cause 19 problems that way with the surface?
20 MR. JUSTICE: So I think to try to address 21 that question, the earthquake activity would occur 22 deep within the, near the Precambrian basin and up.
23 The blemishes we're talking about, the karst 24 depressions, sinkholes, naturally forming areas such 25 as that, are very close to the surface.
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53 1 From my foundation of a nuclear plant, and 2 we will discuss some of that in the next part of the 3 presentation, but from the depth of the foundation of 4 the site and the anchorage of that site, you will have 5 removed any of those considered blemishes in the area 6 for the safety-related feature that you're putting in 7 at the plant.
8 And perhaps, maybe we can table that a 9 little through the next part of the presentation, and 10 then maybe revisit your question and see if we've 11 hopefully enlightened it or can answer it further.
12 MEMBER SUNSERI: Yeah, that's fine. I'm 13 just trying to, you know, it's not my field, so I'm 14 not even going to try to attempt to understand all 15 these intermediate graphs, I just want to get from the 16 beginning to the end kind of conclusion, right.
17 MR. JUSTICE: Understand, thank you for 18 that. Let's go ahead and move to Slide 42, if we can.
19 Just to conclude the seismology portion, the PSHA 20 performed for the Clinch River site, specifically for 21 Sites A and B, we followed 10 CFR 100.23, and we used 22 the guidance of Reg Guide 1.208.
23 It represents the regional and local 24 hazards and includes the local subsurface properties.
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54 1 the dipping angle of 33 degrees.
2 Now I'd move to Slide 44 and discuss the 3 remaining sections of SSAR 2.5. These would be 2.53, 4 2.54, and 2.55. Specifically, these subsections 5 address the following issues: potential surface 6 deformation associated with active tectonism, 7 including any significant neotectonic features and 8 faults; potential surface deformation associated with 9 non-tectonic processes, such as collapse of 10 structures, karst collapse for instance; slope 11 failures; and any human activity, such as mining we 12 talked about earlier.
13 The geological, geophysical, and 14 geotechnical information is used as a basis to 15 evaluate the stability of subsurface materials and 16 foundations at the Clinch River site. And the 17 information presented in this subsection is based on 18 the results of the site-specific subsurface 19 evaluations that were performed at the Clinch River 20 site. Next slide, 45.
21 For surface deformation, TVA has performed 22 geological, seismological, and geophysical 23 investigations and analysis for the region and site.
24 We concluded in the application that the potential for 25 tectonic deformation at the site is negligible.
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55 1 Non-tectonic karst deformation is possible 2 with karst conditions. Detailed mapping of excavation 3 walls and foundations will be performed during 4 construction for a confirmation of the conclusions 5 reached in this application. Next slide.
6 I would like to reiterate some of the 7 investigations and activities that were performed to 8 address the stability of subsurface materials and 9 foundations. We've talked about the previous Clinch 10 River Breeder Reactor Project subsurface 11 investigations and analyses. We also did some 12 additional work, a lot of additional work, for the 13 current project.
14 There were 82 actual geotechnical core 15 borings that were performed at the site. Earlier I 16 told you there were 76 core borings. Those were rock 17 borings, and there were six additional soil borings at 18 the site.
19 We had test pits dug, we had groundwater 20 observation wells. We did down hole geophysical 21 testing in multiple borings. We did groundwater level 22 monitoring in the observation wells, and we did 23 laboratory testing of the boring soil and rock samples 24 that were pulled up from the cores. These programs 25 followed Reg Guide 1.1.32, site investigations for NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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56 1 foundations for nuclear power plants. Next slide.
2 Engineering properties were developed to 3 determine if the site was suitable for support of a 4 nuclear power plant, in conjunction with Reg Guide 5 1.132. These are just a few examples of some of those 6 properties that were investigated. Ultimate bearing 7 capacity, allowable bearing capacity, settlement heat 8 analysis, and additional properties such as rock 9 strength and others.
10 Properties were evaluated against a 11 surrogate plant for the Clinch River site using the 12 plant parameter envelope approach. And I believe that 13 plant parameter envelope approach was discussed 14 previously in an ACRS meeting, but if there are any 15 questions on what that is, I can go back through an 16 explanation of that effort. Okay, moving to the next 17 slide.
18 Due to the identified geological hazard of 19 karst dissolution, additional geotechnical studies 20 were performed to understand the effect on nuclear 21 safety-related foundations. We performed a PLAXIS two 22 dimensional analysis to determine foundation 23 acceptability. We used a large reactor foundation 24 that we selected that a current design because enough 25 detailed information about the four conceptual SMRs NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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57 1 was not available the time we performed the analysis.
2 Finite element models were developed for 3 both Site A and B. These models were done at three 4 different embedment depths, a 40-foot embedment, a 90-5 foot embedment, and a 140-foot embedment.
6 MEMBER CORADINI: Where did you come up 7 with 40, 90, 140?
8 MR. JUSTICE: They will correspond to --
9 MEMBER CORADINI: Potential.
10 MR. JUSTICE: Potential foundation levels 11 for SMRs being considered.
12 MEMBER CORADINI: Okay. I was guessing 13 that, I just wanted to make sure. Undefined, thank 14 you.
15 MR. JUSTICE: You're welcome. The 40-foot 16 embedment was actually done because the embedment 17 depth of the design we used to, as the surrogate model 18 for this site. The 90 and 140 more closely represent 19 embedment depths for the current SMR designs.
20 So for each Site A and B, we did the three 21 different embedment depths. And then, at each of 22 those embedment depths, we then evaluated the 23 placement of the cavity at five foot below the 24 embedment depth and at 30 feet below the embedment 25 depth.
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58 1 And then for each of those models, we then 2 selected three different locations for the placement 3 of the cavity at those depths. It was either at the 4 edge of the nuclear island, at the center of the 5 nuclear island, or at the appropriate bedding plane 6 for the Site A or B. So multiple models were 7 performed.
8 MEMBER CORADINI: Remind me what the 9 cavity is in relation to the bottom of the embedment.
10 MR. JUSTICE: Five feet --
11 MEMBER CORADINI: Yeah, I understand that 12 but --
13 MR. JUSTICE: Or 30 feet.
14 MEMBER CORADINI: But what do you mean by, 15 I don't understand what you mean by cavities.
16 MR. JUSTICE: Karst cavity.
17 MEMBER CORADINI: Oh, cavity, I'm sorry.
18 MR. JUSTICE: An assumed --
19 MEMBER CORADINI: I got it.
20 MR. JUSTICE: Unfound, couldn't find it, 21 never knew it was there cavity. Hypothetical cavity.
22 And if we turn to the next slide --
23 MEMBER BROWN: Before you do that.
24 MR. JUSTICE: Yes?
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59 1 large PWR being satisfactory as opposed to an SMR?
2 MR. JUSTICE: We looked at --
3 MEMBER BROWN: They are different.
4 MR. JUSTICE: They are different. You 5 have similar building sizes in a lot of cases, even 6 though an SMR is small. In some cases, their 7 footprint can be almost as large as a current, modern 8 PWR. We knew the information from the design, and we 9 knew that that information had been previously 10 reviewed and approved in a DCA or other method by the 11 NRC. So the information was known and available.
12 If you'll allow me, in a couple slides, we 13 get to do this analysis again for the technology --
14 (Simultaneous Speaking.)
15 MEMBER BROWN: I'll be happy to allow you.
16 MR. JUSTICE: Thank you.
17 MEMBER BROWN: This is not my area, just 18 seemed to stick out, that's all. Thank you.
19 MR. JUSTICE: Our attempt at this was to 20 do as many different scenarios as we could to fully 21 explain the effect that an unknown cavity may have on 22 our geology, with the best information possible at the 23 time from the application.
24 If we go to the next slide, which should 25 be 49, this is an example of a Site B. This is a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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60 1 finite element model for cavity placement for Site B, 2 with a cavity diameter assumed of 15 feet. So the 3 unknown cavity's 15 feet. At the center of the 4 nuclear island, so we can see it's, if you can see my 5 little red dot. And the foundation is at a 90-foot 6 embedment depth.
7 So this is just an example of a sheet 8 pulled out from the finite element analysis.
9 CHAIRMAN KIRCHNER: And the basis for 15-10 foot diameter is that you would probably detect 11 anything larger than that when you do your site, final 12 site where, before you start laying the concrete in?
13 MR. JUSTICE: That is one point, and it 14 also corresponds to what we have found, either through 15 the Breeder Reactor or through the investigations we 16 did for the SMR.
17 MEMBER RICCARDELLA: Would you point to 18 the cavity again, please?
19 MR. JUSTICE: I'm sorry, did you say the 20 cavity?
21 MEMBER RICCARDELLA: Yeah.
22 MR. JUSTICE: Yes, it is, yeah. Sorry, 23 this doesn't show it for some reason on that blue.
24 MEMBER RICCARDELLA: Got it.
25 MR. JUSTICE: So this again was at the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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61 1 center of the island. It was a 15-foot cavity placed 2 five feet below at a 90-foot embedment depth for the 3 rock units associated with Site B. And if we go to 4 the next slide.
5 Just to reiterate the foundation model 6 results, the development in the site areas is 7 generally limited to the most markedly weather zone, 8 okay. We've discussed that before in how karst is 9 formed and where you find it and at what depths.
10 Typically, these are to depths less than 11 100 feet. Seventy-five percent of reported cavities 12 in the Site A and B borings occurred at depths less 13 than 55 feet. And of course this material, if those 14 sites are chosen, that material would be excavated and 15 removed.
16 Cavity-related failure has a higher 17 potential to occur at relatively shallow depth, less 18 than about 30 feet. But the technologies that we are 19 considering under this application have embedment 20 depths between 80 and 140 feet. Precisely, they are 21 at 86 feet and 138 feet as we move forward with the 22 designs of these different facilities.
23 And we chose the 15-foot cavity as the 24 terminal cavity for this analysis because it bounded 25 the size cavities that we had found in the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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62 1 investigation for both the Clinch River Breeder 2 Reactor and from the current SMR evaluations. Next 3 slide, please.
4 Now to help with last question. So at 5 COLA, if TVA moves forward with a COLA, the foundation 6 performance will have to be re-evaluated based on that 7 technology. And that technology would then have a DCA 8 or a DCV that provides the requisite information you 9 would need to do this type of analysis.
10 It would take into account the specific 11 plant design, the loads, any potential ground 12 improvement or grouting plans that may be necessary if 13 you find --
14 MEMBER CORADINI: So grouting is what 15 you'd stick in the hole.
16 MR. JUSTICE: So once you dig an 17 excavation, you then do mapping and you do additional 18 investigations to determine if in that area where our 19 safety-related foundations are going, are there karst 20 cavities. If you do find karst cavities, per 21 regulatory requirements, then you come up with a 22 grouting plan and a mitigation plan to deal with the 23 karst cavities.
24 It is not an unusual practice, it happens 25 in a lot of the areas where karst is normally found in NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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63 1 the eastern United States. And there's plenty of 2 regulatory guidance to tell you how to do that. But 3 we won't do any of that until we have an actual 4 technology pick for the site.
5 MEMBER RICCARDELLA: So is PLAXIS, is that 6 a finite element computer code?
7 MR. JUSTICE: Yes. The PLAXIS analysis 8 that was used for this is a finite element analysis 9 model.
10 MEMBER RICCARDELLA: And what is the 11 loading that you use, is it just the dead weight of 12 the structure, or do you put in seismic loads as well?
13 MR. JUSTICE: It is the information, it 14 would be the loading of the plant. It would be the 15 footprint of the plant for a nuclear island. And it's 16 a --
17 MEMBER RICCARDELLA: But it's just the 18 dead weight, basically.
19 MR. JUSTICE: And footprint.
20 MEMBER RICCARDELLA: The footprint.
21 MR. JUSTICE: And footprint weight.
22 MEMBER RICCARDELLA: Oh, spread over that 23 footprint, I assume.
24 MR. JUSTICE: Half of the building out --
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64 1 looking at the effects of, for example, cavities on a 2 seismic loading.
3 MR. JUSTICE: No, we're just, you're 4 looking at it from the effect of, as prescribed by 5 1.132, the effects of potential unrecognized cavities 6 under a safety-related foundation. Can you find them, 7 if you'd missed one, would it be okay. And if you do 8 find them, can you mitigate them through grouting 9 methods to shore that up.
10 MEMBER RICCARDELLA: Thank you.
11 MEMBER CORRADINI: So if one of these 12 technologies wants to do seismic isolation, would any 13 of this procedure change? Or that's more within the 14 plant and the plant response to these, to this seismic 15 source and the associated required foundation 16 improvement.
17 MR. JUSTICE: So that would be considered 18 in the infrastructure and seismic evaluation for the 19 actual plant. But the characterization efforts would 20 still be the same.
21 MEMBER CORRADINI: Okay.
22 MR. JUSTICE: As we have done for this 23 application.
24 MEMBER CORRADINI: Thank you.
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65 1 now move to Slide 52, discuss a little bit of 2 stability of slopes. Giving the existing topography, 3 the natural topography, and the planned finish grade 4 as described in the application. So basically it 5 would be a flat site with no safety-related slope 6 planned in the vicinity of safety-related structures.
7 However, the stability of slopes as 8 identified in the application will be re-evaluated 9 during the COLA phase based on the actual technology 10 selected.
11 And just to note, the previous Breeder 12 Reactor excavation experience, the reports from that 13 are very helpful also in determining this as it goes 14 forward in future. Last slide, please.
15 In summary, the early permit application 16 seeks approval for the Clinch River site for potential 17 future use of a small modular reactor technology. The 18 Clinch River site is capable from a geologic and 19 seismic perspective for the construction of a small 20 modular reactor.
21 As we discussed, the potential hazard, 22 karst, is identifiable and can be mitigated through 23 approved regulatory processes.
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66 1 process and the site audit and visit were very helpful 2 in ensuring that the right level of detail and 3 supporting information was available in the 4 application. And I would like to thank you for your 5 time in listening and preparing in this presentation.
6 Thank you.
7 CHAIRMAN KIRCHNER: Let's go around the 8 table, then. Any of the members have questions, 9 further questions of the applicant?
10 I have one question. In the unlikely 11 event you didn't detect a cavity, highly unlikely I 12 would guess, but would it appreciably change, my 13 intuition says no to this question, but would it 14 appreciably change the seismic loading in any way?
15 You've got pretty hard rock that you're --
16 MR. JUSTICE: No.
17 CHAIRMAN KIRCHNER: Building this plant 18 on. So I wouldn't expect that, but that would be my 19 question.
20 MR. JUSTICE: That, and your assumption is 21 correct. That would not, the identification of 22 cavities in the safety-related excavation, additional 23 borings will be performed, additional methods of 24 detection of cavities.
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67 1 excavation. You've now removed a 100 foot of 2 material. You've most likely removed the vast 3 majority of your karsistic material. But you're still 4 going to attempt to identify everything you can in 5 that excavation.
6 If you find a karsistic area, then you 7 will then follow regulatory prescribed mitigation 8 plans to fill those voids. The PLAXIS analysis is a 9 pretty conservative view of you just somehow missed it 10 and now you are determining what is the largest cavity 11 that you could have that still, with the weight of the 12 plant and the design of the plant, would not affect 13 that safety-related foundation.
14 And again, that gets redone for this 15 project if the project moves to a COLA phase for the 16 specific technology that would then be picked and 17 aligned with the COLA.
18 CHAIRMAN KIRCHNER: Thank you. Okay, with 19 that, let's go to the staff. Andy. Or you want to 20 break? Don't you want to go right through? Okay, 21 let's take a break. And Qyunh will explain where the 22 facilities are located. So we're, are we recessed or 23 adjourned? We're recessing? Okay.
24 MR. CAMPBELL: And I'm going to let the 25 staff sit up here for the presentation or wherever.
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68 1 You have a table for them, okay, great. Thank you.
2 MR. JUSTICE: We're vacating.
3 MR. NGUYEN: Okay. Dr. Kirchner, when do 4 you want people back? Twenty-five of three? Okay, so 5 if you need to use the facilities, go out of this 6 room, turn a left, and keep hugging that corridor and 7 you'll find the restrooms.
8 There is a convenience store right before 9 the security turnstiles. I don't know what's in 10 there, but feel free to check it out. And for the 11 members, there's some coffee and Munchkins.
12 (Whereupon, the above-entitled matter went 13 off the record at 2:22 p.m. and resumed at 2:35 p.m.)
14 CHAIRMAN KIRCHNER: Okay. Let's reconvene 15 and we're going to turn to the staff.
16 Andy, are you going to make any 17 introductions or are they going to introduce 18 themselves?
19 MR. CAMPBELL: I will happily let them 20 introduce themselves, but I did want to introduce Dr.
21 Cliff Munson, who's our senior-level advisor for 22 siting, who's joined me at the table --
23 CHAIRMAN KIRCHNER: Uh-huh.
24 MR. CAMPBELL: -- and I'll let Allen take 25 it from there.
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69 1 CHAIRMAN KIRCHNER: Okay.
2 MR. CAMPBELL: And I don't have anything 3 else to add, but this has been the culmination of a 4 lot of outstanding effort on the part of the staff in 5 their reviews through this whole project, and I'm 6 going to let Allen take it from there. Thank you.
7 MR. FETTER: Yes.
8 CHAIRMAN KIRCHNER: Okay.
9 MR. FETTER: Good afternoon.
10 Everyone hear me okay?
11 Yes, I'm Allen Fetter, one of the two 12 safety project managers on the Clinch River review.
13 Mallecia Sutton, who is the other safety project 14 manager, had to duck out to finish the SEs for the 15 next ACRS meeting on the 14th.
16 So, Ms. Sutton and I will be at the table 17 for the next ACRS meeting on SE Sections 2.3, 2.4.11 18 and 17 on November 14th, 2018.
19 So, I've been at the NRC since 2004, and 20 in 2009 I started working as a project manager in the 21 Office of New Reactors.
22 Prior to taking over as safety project 23 manager on the Clinch River ESP review in July 2015, 24 I was an environmental project manager for the 25 Bellefonte COL and the PSEG early site permit reviews.
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70 1 Today's ACRS meeting is the fourth meeting 2 that TVA and NRC and the ACRS have had together. This 3 is the third of four subcommittee meetings on the SEs 4 that have been prepared for the project.
5 Today, the NRO Geoscience, Geotechnical 6 and Engineering Branch technical reviewers, listed on 7 this slide with their credentials, will give 8 presentations on their safety evaluations under 9 Section 2.5, Geology, Seismology and Geotechnical 10 Engineering.
11 Of course you will have the opportunity to 12 ask questions throughout the presentations and for the 13 sections discussed today.
14 In addition to staff's review of TVA's 15 application, staff conducted two audits, one site 16 visit and issued three RAIs comprising ten questions 17 to the Applicant in order to obtain additional 18 information to support NRC's findings.
19 I will now turn it over to Dr. Gerry 20 Stirewalt and Ms. Jenise Thompson for the first part 21 of the presentation.
22 DR. STIREWALT: Thank you, Allen.
23 Good afternoon. I am indeed Gerry 24 Stirewalt. What we would like to do, we'd like to 25 discuss the pure geology pieces, 2.5.1 and 2.5.3 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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71 1 first.
2 So, I'll start with 2.5.1, which is 3 titled "Geologic Characterization Information." And 4 if we could take a look at Slide 4 just as a reminder 5 of what the SSAR includes that the Applicant prepared, 6 2.5.1 -- again, Geologic Characterization Information 7 is divided into two subsections.
8 2.5.1.1 relates to original geology. Let 9 me remind you that that region is a 200-mile radius 10 around the site.
11 The Applicant presented information on 12 physiography, geomorphic processes, geologic history, 13 tectonic evolutions, stratigraphy, tectonic setting, 14 including distribution of seismicity and stress in the 15 eastern U.S., and certainly nontectonic hazards 16 including karst.
17 2.5.1.2 gets -- it sort of narrows down 18 the scope of where the data was collected and 19 evaluated. Local geology relates to site vicinity 20 that's 25 miles, site area that's five miles, and site 21 location, which is a 6/10th of a mile radius of the 22 site.
23 And, again, similar things were reviewed 24 at this scale as well; physiography, geomorphic 25 processes, geologic history, stratigraphy, lithology, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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72 1 structural geology, including faults and shear-2 fracture zones in particular, geologic hazards, 3 including karst, and certainly the site engineering 4 geology piece that included potential effects of human 5 activity.
6 Let me, in the next slide, just sort of 7 remind you of the physiographic scene. The site is 8 located in the valley and ridge physiographic 9 province, and the parallel ridges in that province 10 really developed as a result of differential 11 weathering and erosion of the folded and faulted 12 sedimentary rock strata that characterized that 13 province.
14 Okay. Let's think about what the -- so, 15 what are the key geologic features of interest here?
16 Well, there are two. One, is the regional thrust 17 faults; and the other is the localized shear-fracture 18 zones.
19 Now, neither of those two features is 20 really well-exposed at the surface in the site area.
21 Staff are able to examine them in rock core samples 22 that the Applicant provided during site audits and 23 site visits and both of those features, as you have 24 heard mentioned before, are generally parallel to 25 bedding.
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73 1 Okay. So, the thrust faults are, in fact, 2 tectonic in origin and they are regional features.
3 The shear-fracture zones are more localized and they 4 contain features of both a nontectonic and probable 5 tectonic overprint origin.
6 Okay. So, the important thing that the 7 staff really needed to focus on was determining and 8 documenting that the thrust faults and the shear-9 fracture zones are, in fact, older than Quaternary --
10 that's greater than 2.6 million years in age -- and 11 consequently pose a negligible hazard for the site.
12 So, it was really important to confirm the 13 ages of these features just to make certain that they 14 didn't pose a problem.
15 Okay. Let's do a quick look at a cross-16 section that you've seen just to sort of show you, 17 again, the subsurface stratigraphy, faults and shear-18 fracture zones.
19 This profile essentially crosses the 20 entire site location and extends beyond. What I would 21 like to point out to you, on this particular slide, 22 are the Copper Creek fault that is revealed in 23 borehole CCB2.
24 And I mention that because I'm going to 25 take you into the field and show you what it looks NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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74 1 like in core.
2 The other fault that actually occurs that 3 was also mentioned, is the Chestnut Ridge fault.
4 That's really a local fault. Has the same orientation 5 as the regional structures, but it's really localized, 6 but the Copper Creek certainly is very characteristic 7 of what the regional thrust faults look like.
8 We're also going to take a look in the 9 field -- I'm a geologist. I have to take you into the 10 field, after all.
11 We're going to take a look at the shear-12 fracture zone in the Rockdell formation in borehole 13 MP-101.
14 Now, one thing I'd like to mention, this 15 cross-section is actually vertically exaggerated. So, 16 the depth that you keep hearing mentioned of around 33 17 degrees are exaggerated.
18 So, let me take you into the field really 19 quickly, show you an exposure of the Fleanor 20 formation. This is within the site location and, in 21 fact, this really shows the amount and direction of 22 the dip of bedding that is commonly seen at the site.
23 And the bed's around 33 degrees southeast dipping 24 towards the geologic scale that you have.
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75 1 then. Again, they are characteristic of the entire 2 Valley and Ridge province in which the site is 3 located. They do occur in the site area.
4 And, again, there is no surface expression 5 of any thrust faults in the site area, so -- and 6 although not exposed at the surface, I pointed out the 7 Copper Creek and Chestnut Ridge faults that are 8 located within the site location at 0.6 miles from the 9 site.
10 During the site audits and the site visit, 11 staff were able to examine the Copper Creek fault and 12 core from borehole CCB2.
13 And I'm going to drag you into the field 14 and let you take a look at that in a moment, but I 15 just wanted to mention that the Copper Creek, although 16 it's not exposed at the surface at the site, is very 17 well-exposed in the site region and, again, it's 18 typical of the orientation northeast-striking, 19 southeast-dipping faults that characterize the entire 20 valley and ridge.
21 Okay. Let's take a quick look again at 22 the site area itself. That's the big red circle, and 23 the smaller one is the site location.
24 You will note that the site is, in fact, 25 located between two of these regional thrust faults.
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76 1 One is the Copper Creek; the other is the Whiteoak 2 Mountain fault.
3 So, geometrically, what that is, you have 4 the Whiteoak dipping beneath the site about 33 5 degrees, again, parallel to bedding, and the fault 6 that overlies that in that stack of units is the 7 Copper Creek, and the site is located within that 8 fault block in between those two structures.
9 Okay. Well, it's kind of an important 10 thought to note we have an age date on the fault 11 gouge. Okay. What is "fault gouge"?
12 Well, that's when you sort of are grinding 13 the fault along the surface beneath it, you actually 14 crush the rock and mill the rock and grind it. So, 15 it's called cataclasis, but the point is that you 16 develop a gouge, a pulverized rock that's sort of very 17 characteristic and it's due to displacement, in this 18 case, along the Copper Ridge fault.
19 That gouge has been dated at around 280 20 million. Now, it wasn't dated at the site; it was 21 dated at a different location, but it's the same 22 fault.
23 Reported displacement on this fault is 24 ranging between 7 and 31 miles, depending on where you 25 look at it. And with this age date, again, it is NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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77 1 clearly older than Quaternary. No question about 2 that.
3 Well, okay. I promised you a look at 4 stuff in the field, so let's --
5 MEMBER SUNSERI: Just a quick question.
6 DR. STIREWALT: I'm sorry. Yeah, please.
7 MEMBER SUNSERI: Can you tell me, again, 8 what "northeast-striking and southeast-dipping" means?
9 DR. STIREWALT: I certainly can.
10 If I talked about a bed, the strike would 11 be in this direction for this. So, it would be 12 striking towards you and it would be dipping towards 13 my colleagues here.
14 So, that's literally a three-dimensional 15 orientation of that fault surface and, in fact, the 16 bedding, because they're parallel. Good question.
17 Thank you. Sorry, I got carried away.
18 MEMBER RICCARDELLA: And would you clarify 19 what the 7.4 to --
20 DR. STIREWALT: Is your mic on?
21 I'm sorry, could you repeat the question?
22 MEMBER RICCARDELLA: Yeah. Would you 23 clarify what you mean by the 12 to 50 kilometers of 24 displacement along the fault?
25 DR. STIREWALT: Yes. That's actually NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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78 1 measured -- a question earlier came up about how do 2 you identify a fault? You can look at a marker that's 3 displaced and they can determine, in the field, from 4 field data, that that is the actual displacement --
5 amount of displacement along this fault.
6 And, again, the movement would be like 7 this. So, there's evidence from what they see, in the 8 field, that it has moved somewhere between 7 and 31 9 miles.
10 Of course, I mean, the fault doesn't go on 11 forever. It does dies out. So, the amount of 12 displacement will vary along it. So, a maximum of 13 about 30 miles or so, yeah.
14 Okay. I promise to --
15 MEMBER RICCARDELLA: Sorry. So, I thought 16 I got it, but I don't got it.
17 So, are you saying it's the length of the 18 fault or the actual fact that it moved 31 miles?
19 I thought it was --
20 DR. STIREWALT: Yeah. The displacement is 21 parallel to the fault surface, it's not the length.
22 MEMBER RICCARDELLA: Okay.
23 DR. STIREWALT: That is the actual 24 displacement.
25 MEMBER RICCARDELLA: Okay.
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79 1 DR. STIREWALT: The actual displacement.
2 Am I clear on that?
3 MEMBER RICCARDELLA: And that took place 4 over many years a long, long time ago, right?
5 DR. STIREWALT: Yes. Yes. Because we 6 have this nice, little age date at around 280, so we 7 know it's pretty old.
8 MEMBER RICCARDELLA: Yeah.
9 DR. STIREWALT: Okay. All right. I'm 10 excited to show you what fault gouge looks like.
11 This is, again, along the Copper Creek 12 fault. This is in borehole CCB2 that I located for 13 you, and I hope that you can see a rather clear 14 distinction between the gouge and between the rock 15 that is not involved in faulting.
16 Well, what are some of the differences?
17 Okay. Again, we know the gouge is dated at 280. And 18 if you look at this, I mean, this is really pulverized 19 rock.
20 In the part that's not faulted, you can 21 see very, very well-developed bedding. You don't see 22 anything like that here. It's totally structureless.
23 All the original sedimentary structures that were 24 there before the fault movement are erased, they're 25 gone, they're pulverized.
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80 1 So, this, again, is a -- I think a good 2 illustration and why you would know in the core that, 3 gosh, I'm not looking at a normal stratigraphic 4 sequence. Something has happened to this rock.
5 And what happened to it, in this case, is 6 30 or so miles of displacement along the Copper Creek 7 fault.
8 Any questions on that?
9 Okay. Well, then let's talk about the 10 shear-fracture zones. They were of concern because we 11 wanted to make certain that there wasn't anything 12 related to those particular features that suggested 13 Quaternary deformation.
14 Now, you've already heard that the shear-15 fracture zones at the site contain pressure solution 16 features, namely stylolites, in two different 17 orientations. So, two sets of these solution 18 features. They are both parallel and perpendicular to 19 bedding.
20 Now, those features tell us some really 21 important stuff about the orientation of the stresses 22 that must have influenced those shear-fracture zones.
23 So, let me just sort of talk about that a bit.
24 The -- maybe I should qualify. The reason 25 you can see a stylolite, and you saw them in the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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81 1 earlier slides -- I'm going to show you in another 2 slide, but the reason you can actually see this little 3 surface where the dissolution occurred, is because 4 when you -- again, the stress itself operates 5 perpendicular to the dissolution feature and you can 6 actually see it because I'm dissolving a limestone.
7 You have parts, clays and things, that do 8 not dissolve and, lo and behold, they concentrate 9 right along that little surface so you can see -- you 10 can see a little crinkly line that's marked by 11 minerals that did not dissolve. And that's how --
12 that's why you can see the stylolite.
13 Okay. The nontectonic bedding-parallel 14 stylolites that, again, are the earliest, these formed 15 during deposition and lithification of the sedimentary 16 units due to the vertical overburden pressure.
17 That is to say as you're stacking --
18 depositing this rock, stacking them one on top of the 19 other, you develop a very thick overburden. And that 20 overburden produces a stress that's perpendicular to 21 bedding, just like those stylolites, and that's the 22 source.
23 So, this is syndepositional sort of 24 nontectonic strictly, but it occurred very, very 25 early.
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82 1 All right. Now, the bedding perpendicular 2 stylolites, which are the latest, likely formed in 3 response to the near-horizontal stresses related to 4 transport of the flow sheets.
5 And we know that timing is around 280 6 million, so they're old, also, but the point is that 7 it is a tectonic overprinting, but that tectonic 8 overprinting is not Quaternary in age. It's also 9 very, very old. Very, very old.
10 So, during the site audits and site 11 visits, then, staff were able to examine the shear-12 fracture zone specifically on the Rockdell formation 13 in borehole MP-101.
14 And, guess what. As you suspected, I'm 15 going to show you that. You saw this same piece of 16 core in something that the Applicant presented, but 17 what I'd like to do, I just sort of blew up one part 18 of it to sort of note that bedding is well-developed, 19 you can see bedding surfaces; you can see these little 20 squiggly, dark-colored lines marked by the clay that 21 didn't dissolve that are parallel to bedding; and you 22 can also see some that are perpendicular to bedding.
23 Now, again, since these features form 24 essentially perpendicular to the causative stress, 25 they must have developed at two different times. And NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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83 1 we have the timing of the latest because of the dating 2 on the fault motion. It's around 280 million.
3 So, again, that sort of sets the scene for 4 the conclusions that we can make about any concerns 5 related to tectonic features that are young Quaternary 6 at the site.
7 If there are no questions on that picture, 8 let's take the final slide and let's sort of address 9 the conclusions.
10 Again, no tectonic features with the 11 potential for adversely affecting suitability of the 12 site occur in the site region, the site vicinity, the 13 site area or at the site location. That is to say, no 14 data suggests the presence of Quaternary tectonic 15 features.
16 In fact, the primary event that's 17 registered, which is development of the regional 18 thrust faults, is dated around 280 million.
19 It's kind of geologically fun to think 20 about that that actually happened when Africa was 21 colliding with North America, growing the Appalachian 22 Mountains to the east of this. So, it's a part of 23 that major tectonic package, but that's exciting to a 24 geologist anyway.
25 Okay. And, again, no field data --
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84 1 CHAIRMAN KIRCHNER: An earlier slide had 2 it 280.3 or something.
3 DR. STIREWALT: Yeah. 279 --
4 CHAIRMAN KIRCHNER: So, how do you get 5 such precision in this dating? How did they derive 6 significant figures?
7 DR. STIREWALT: Well, it's done with 8 radiometric dating using --
9 CHAIRMAN KIRCHNER: Okay.
10 DR. STIREWALT: -- I believe it was argon-11 argon in this case. And you still have that era band 12 (phonetic) on it, but, I mean, it --
13 CHAIRMAN KIRCHNER: It's not using argon 14 in the laboratory.
15 Is argon the element --
16 DR. STIREWALT: Yes.
17 CHAIRMAN KIRCHNER: -- just for the public 18 record?
19 DR. STIREWALT: Yes. Yes.
20 CHAIRMAN KIRCHNER: Okay.
21 MR. FETTER: Potassium-argon, argon-argon.
22 DR. STIREWALT: Yeah. That's a good 23 question.
24 Okay. And, again, there's no field 25 evidence that suggests the shear-fracture zones are NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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85 1 younger than that thrusting event which, again, really 2 pins it as being certainly older -- certainly 3 preQuaternary age, which was our concern.
4 Well, there's no question that karst is a 5 primary nontectonic feature that's recognized, and 6 that does have a potential for adversely affecting 7 site suitability.
8 Certainly the Applicant described the 9 geologic characteristics of the site region, site 10 vicinity, site area, site location in full compliance 11 with the regulatory requirements and in accordance 12 with guidance in 1.208.
13 Are there other questions or comments or 14 anything on this?
15 Okay. Well, that being the case, I am 16 pleased to pass the talking baton to my colleague, Ms.
17 Jenise Thompson, who will speak to 2.5.3; and you may 18 be certain she is going to mention karst.
19 MS. THOMPSON: And show lots of pictures.
20 My name is Jenise Thompson. I was the 21 primary reviewer to Section 2.5.3, Surface 22 Deformation.
23 So, in Section 2.5.3, we focused on the 24 information related to the assessment of both tectonic 25 and nontectonic surface deformation and the potential NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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86 1 for that surface deformation.
2 So, at the Clinch River site, we looked 3 specifically at geologic features observed in the East 4 Tennessee seismic zone and at numerous karst-related 5 features that were observed in the site area.
6 So, for tectonic surface deformation, we 7 looked at potential for tectonic surface deformation 8 in the site area and concluded that there were no 9 Quaternary age tectonic structures near the site 10 location.
11 So, this was based on available data that 12 showed negligible potential for surface deformation 13 due to tectonics.
14 We also looked at river terraces. I know 15 that the Applicant mentioned a rather extensive river 16 terrace study that they did.
17 We observed those terraces in the field 18 and saw no evidence of surface deformation that could 19 be attributed to tectonics.
20 So, the staff concludes that there's no 21 evidence of Quaternary age tectonic surface 22 deformation at the site.
23 The relationship of potential tectonic 24 surface deformation to observe seismicity in the East 25 Tennessee seismic zone is undetermined.
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87 1 Due to carbonate rocks in the subsurface, 2 direct observation of karst features in the field and 3 ongoing dissolution processes in the site vicinity and 4 interpreted cavities in the rock core, as indicated by 5 missing segments, which I will show you, the staff 6 concluded that karst has the potential to cause 7 surface deformation at the Clinch River site.
8 So, you saw this picture earlier. This is 9 the distribution of karst features in the Clinch River 10 site area.
11 MEMBER BROWN: Could you go back a slide, 12 please. 16. You said the relationship between the 13 deformation and observed seismicity is undetermined.
14 That sounds not like a good conclusion.
15 You don't know what's going on.
16 MS. THOMPSON: There are features within 17 the site vicinity and the site region, so not within 18 the five-mile site area, that are still under study.
19 And there are numerous possibilities of what their 20 origin could be, but none of them have been 21 definitively determined to be related to seismicity in 22 the East Tennessee seismic zone.
23 MEMBER BROWN: Does that have any meaning 24 relative to the positioning of this plant in this 25 location?
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88 1 What's the conclusion?
2 Is it it doesn't bother siting this 3 particular potential plant in this region?
4 Is that what that means?
5 MS. THOMPSON: My colleague David will 6 address that more in his discussion of the vibratory 7 ground motion in Section 2.5.2.
8 MEMBER BROWN: Okay. Well, I'm old enough 9 I may not remember this by that time.
10 (Laughter.)
11 MS. THOMPSON: David will.
12 MEMBER BROWN: Thank you.
13 MS. THOMPSON: So, moving on to karst, 14 each of the black dots shown here is a karst 15 depression.
16 So, there were approximately just under 17 3,000 karst depressions or karst features mapped in 18 the five-mile radius of the Clinch River site, which 19 is that red star in the center.
20 So, these depressions can be any number of 21 forms. They can be swales, which are kind of a small, 22 wet depression at the surface; a swallet, which is 23 slightly larger and usually has some percolation or 24 water draining in it; or sinkholes, which the 25 Applicant showed you some great examples of, which is NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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89 1 that surface depression which is the result of 2 subsurface dissolution and collapse. So, that's how 3 we can kind of see what's going on in the subsurface 4 without digging down into the ground.
5 Something to note here, Gerry was talking 6 about the dip of the layers. And you can see the blue 7 dip angle -- dip symbols here showing you what 8 direction these layers are dipping, and you'll notice 9 that most of these depressions, these karst features 10 are in the Knox group, which is that tan color; there 11 are a few in the Chickamauga group, which is what's 12 underlying the Clinch River site; and then there are 13 just a handful in the Conasauga group, but all three 14 of those groups are present in the subsurface because 15 of that dip angle.
16 So, we also observed cavities in the rock 17 core at the site that was part of the boring program.
18 So, one interpretation of these cavities is that they 19 may be recording the cavities that we see for karst 20 and dissolution features.
21 So, this particular cavity was mapped here 22 in borehole MP-418, and the cavities were of varying 23 thicknesses.
24 In total, there were 238 cavities 25 encountered in the boreholes of numerous, varying NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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90 1 sizes. Anything that was more than a tenth of a foot 2 of no recovery was mapped as a cavity in the boring 3 logs.
4 So, they were encountered -- these 5 cavities were encountered in all of the subsurface 6 units that the boreholes encountered, but the size 7 differs.
8 So, when you have the more pure carbonates 9 of the limestone units, you would have larger and more 10 frequent cavities. Whereas when you have the more 11 classic units, some of the siltstones, you would have 12 smaller and less frequent cavities.
13 So, one possible interpretation of what 14 these cavities could be representative of is pinnacle 15 and cutter karst -- or buried pinnacle and cutter 16 karst.
17 And so, these are two examples of 18 pinnacle and cutter karst that the staff observed 19 within the five-mile site area. And pinnacle and 20 cutter karst is the result of dissolution along joints 21 and bedding planes and it could result in these 22 cavities.
23 And so, on the left picture, you see my 24 colleague's hand here and this is the joint along 25 which you have dissolution and you end up with this NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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91 1 larger dissolution pit.
2 The depth of this, I can stick my arm all 3 the way in to my shoulder, and I could keep going if 4 I had larger arms.
5 And then for -- on the lower right, this 6 is a typical exposure of the pinnacles that you see.
7 So, we have these high points, and then you would have 8 the joints at the low points here, which is where you 9 have your dissolution occurring, and it kind of looks 10 like a jawbone in this kind of classical exposure of 11 pinnacle and cutter karst.
12 So, some of the things that you might see 13 in borings that would lead you to think that it would 14 be buried pinnacle and cutter karst would be different 15 thicknesses of soil or overburden or filled-in 16 cavities that have kind of soil or other material that 17 is not consistent with the subsurface layers that you 18 would expect to see.
19 So, additional karst features that we saw, 20 we mentioned the swales, the swallets and the 21 sinkholes, which are additionally the surficial karst 22 depressions that we see.
23 And I use this picture because this is the 24 best one that I have of a clear sinkhole. So, you can 25 see that classic karst depression and what it looks NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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92 1 like.
2 And this is 4 1/2 miles east of the Clinch 3 River site near the Melton Hill Dam, and the rim of 4 this depression is generally the tree line and where 5 this nice little house is sitting.
6 So, you would have water flow down the 7 slope into this sinkhole here where you have ponded 8 water, but there is active percolation. So, the 9 presence of ponded water is generally determined on a 10 precipitation event.
11 So, if you were to come in the middle of 12 a drought, there wouldn't necessarily be ponded water, 13 but this is one of the examples of many of the 14 sinkholes that the staff went and observed at the 15 site.
16 Another karst feature that was observed in 17 the site area was caves, which are kind of the classic 18 karst feature.
19 So, the Copper Ridge cave was the largest 20 cave that the staff visited in the Clinch River site 21 area, and this occurs in the basal unit of the Knox 22 group, which, again, because of that dip angle of the 23 units below the Clinch River site, the Knox group is 24 present in the subsurface.
25 And this is a cave that occurs inside a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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93 1 closed basin in a hill slope. So, you have this 2 closed depression -- that's the rim, the dotted line 3 there -- you have a flow down into the joint, which 4 continues here -- there's the entrance to the cave --
5 and that line in the roof, that joint, that small 6 break in the roof, that's where dissolution is 7 occurring.
8 You also have dissolution along bedding 9 planes. As you can see down here at the yellow arrow, 10 you kind of have that dissolution where you have some 11 units that are more prominent than others.
12 And supporting this dissolution along 13 joints and bedding planes is that this cave follows 14 the orientation of the joint through a 90-degree turn 15 just inside the entrance to the cave. So, you have 16 dissolution along the joint, and when the joint turns 17 90 degrees, the cave follows.
18 So, given the presence of karst and the 19 numerous karst features in the site area, the 20 Applicant acknowledged the need to perform geologic 21 mapping for documenting the presence or absence of 22 karst features, faults or shear-fracture zones in 23 plant foundation materials.
24 Accordingly, the staff identified Permit 25 Condition 1, which is here, to allow the staff to NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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94 1 confirm and the Applicant to verify the determinations 2 made at the ESP stage with respect to surface 3 deformation. And then, if necessary, to mitigate any 4 potential hazard through the appropriate means.
5 MEMBER CORRADINI: So, they would map out 6 where the holes are. And then if they are of a 7 certain size, they would have to be filled or is that 8 left to the Applicant? That's what I'm curious about.
9 MS. THOMPSON: This will be addressed at 10 the COL stage. So, if there are -- so, they will 11 perform the mapping and it will be made available for 12 the staff to go into the field and examine.
13 And then if anything is identified, it 14 will be up to the Applicant to determine an 15 appropriate mitigation plan.
16 MEMBER CORRADINI: So, they can suggest a 17 remedy which you can then --
18 MS. THOMPSON: Yes. And that goes to 19 something -- the permit condition, the confirmatory 20 activities, which would include the geologic mapping 21 and, if necessary, the development and implementation 22 of a mitigation plan were -- are all included as part 23 of COL Action Item 2.5-3 in Section 2.5.4 of the ESP.
24 MEMBER CORRADINI: So, if they map out --
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95 1 have an embedment that's a hundred feet deep and so 2 wide and so deep -- or so wide and long based on a 3 particular design, if they map out the cavities, is 4 there -- and they find that they have -- I'll pick a 5 number -- ten of them three feet or less, is there 6 some smaller -- is the size of the cavity determined 7 on how one would remedy it or is there a prescribed 8 approach?
9 I'm still trying to understand what this 10 condition means other than look, see what you find and 11 report back.
12 DR. HEESZEL: Or mitigate as needed.
13 MEMBER CORRADINI: Or mitigate as needed, 14 but what I -- then my next question is that once they 15 repot back and they suggest a remedy, are there 16 acceptable remedies that have been done in the past 17 and they would just pick from those or is it quite 18 customized to the region? That's what I'm trying to 19 understand.
20 MEMBER RAY: Before you respond, isn't 21 this just a carve-out from the normal scope of an ESP?
22 In other words, it simply can't be addressed until --
23 MS. CANDELARIO: Yes.
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96 1 until COL application --
2 MEMBER RAY: There's no prescribed 3 solution --
4 MS. CANDELARIO: Right.
5 MEMBER RAY: -- no criteria that are 6 preestablished or anything like that.
7 MS. CANDELARIO: Right. But if they find 8 voids on the geologic mapping phase, then the COL 9 applicant will address that as part of COL Action Item 10 2.5.3 which I can read.
11 And it says, an applicant for a COL or CP 12 referencing this early site permit should design and 13 conduct additional subsurface investigation during 14 excavation and construction to detect cavities below 15 the foundation elevation that could adversely affect 16 condition performance. In addition, the Applicant 17 should perform confirmatory drilling or borehole 18 testing during excavation/construction to characterize 19 the source of geophysical anomalies and to develop a 20 grouting program with associated ITAACs when needed 21 based on the information obtained by the geologic 22 mapping, geophysical surveys and specific analysis to 23 mitigate the effect of bores or cavities on foundation 24 performance at and below the foundation level of the 25 safety-related structure.
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97 1 MEMBER RAY: Okay. Thank you.
2 MS. THOMPSON: Thank you, Luissette.
3 So the staff's conclusions on the next 4 slide are as follows: "The staff concludes that a 5 negligible potential exists for tectonic surface 6 deformation that could adversely affect the 7 suitability of the Clinch River site. Staff also 8 concludes that karst is the primary potential hazard 9 for nontectonic surface deformation at the Clinch 10 River site. The staff further concludes that the 11 Applicant described the information related to the 12 assessment of the potential for tectonic and 13 nontectonic surface deformation in full compliance 14 with the regulatory requirements."
15 CHAIRMAN KIRCHNER: So, this addresses 16 what Charlie raised earlier. It just struck me, as 17 well as him, that your Slide 16, that first bullet, 18 that's rather a sweeping conclusion because your 19 summary slide says that there's not a problem.
20 In other words, in 16 you say "surface 21 deformation in this area is largely undetermined," but 22 then you go on and draw a conclusion that says, "for 23 this site, negligible potential exists for tectonic 24 surface deformation." That would be adverse.
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98 1 16 is that the relationship between tectonic surface 2 deformation and the observed seismicity in the East 3 Tennessee seismic zone is undetermined, but that does 4 not -- that's not in conflict with our conclusion that 5 there's a negligible potential for tectonic surface 6 deformation at the site.
7 And David will get a little more into the 8 relationship in the seismicity of the East Tennessee 9 seismic zone and how it may affect the site; but from 10 the perspective of surface deformation and what 11 evidence we have now and the conclusions that we have 12 available to us, there is a negligible potential for 13 tectonic surface deformation to affect the site.
14 CHAIRMAN KIRCHNER: Okay.
15 MEMBER BROWN: Would you say that again?
16 There is -- did you say "negligible"?
17 MS. THOMPSON: Negligible potential --
18 MEMBER BROWN: Okay. I didn't hear you.
19 MS. THOMPSON: -- for tectonic surface 20 deformation to affect the site.
21 The primary hazard for surface 22 deformation, either tectonic or nontectonic, at the 23 Clinch River site is karst.
24 MEMBER BROWN: You gave us a picture and 25 a discussion about the cave and how it went in and it NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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99 1 goes at right angles underground. That didn't look 2 like a very good place to try to mount -- to put the 3 site.
4 That's a nice example, but I'm trying to 5 connect the dots between your example and what they 6 reported in their writeups, in their presentation.
7 MS. THOMPSON: The cave is just under five 8 miles east-northeast of the Clinch River site.
9 MEMBER BROWN: Okay.
10 MS. THOMPSON: And it's within the Knox 11 group, which is in the deep subsurface at the Clinch 12 River site.
13 So, this is the -- the cave -- the example 14 that I used is the Copper Ridge cave and it occurs in 15 the Copper Ridge dolomite, which is the absolute 16 bottom layer of the Knox group.
17 Which, if you remember Gerry's slides of 18 the borings, the deepest boring at the site, I think 19 it just reached the top of the Knox group, which was 20 the Newala formation, and we're talking about what's 21 way at the bottom far below that.
22 But because of the way the faulting in the 23 area has occurred and the exposure of the units, in 24 some areas you have -- the Knox group has -- if you 25 click once -- or, I'm sorry, back to the second slide, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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100 1 Slide 17, I think.
2 So, the Knox group is this one here. So, 3 we're talking about the bottom unit of that. So, 4 something that's like down over here.
5 Do you want us to go back to the picture 6 of the --
7 MEMBER BROWN: No, that's fine.
8 MS. THOMPSON: Yeah.
9 MEMBER BROWN: You could stop on that one 10 you were talking about, gaps. I didn't ask the 11 question at the time. Right there -- no, not that 12 one. It's in your presentation.
13 MS. THOMPSON: Oh, cavities.
14 MEMBER BROWN: Cavities.
15 MS. THOMPSON: Yes.
16 MEMBER BROWN: Where are the cavities?
17 What should we look at in that picture for the 18 cavities?
19 MS. THOMPSON: So, this is the --
20 MEMBER BROWN: Right there?
21 MS. THOMPSON: -- recovered core.
22 MEMBER BROWN: Okay.
23 MS. THOMPSON: And this here -- and I'm 24 sorry the picture is not lighter, but this is a --
25 basically a pool noodle that is marking no recovery.
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101 1 So, it's a foam tube that's marking that 2 there was no rock recovered between 59 feet and I 3 think that's 63. So, you had about a four-foot period 4 of no recovery.
5 CHAIRMAN KIRCHNER: So, meters down from 6 the surface where that borehole was extracted --
7 MS. THOMPSON: Yes. So, this is the --
8 CHAIRMAN KIRCHNER: -- that sample was 9 extracted.
10 MS. THOMPSON: Yes.
11 MEMBER BROWN: Okay.
12 MS. THOMPSON: So, this is depth. So, 13 this is just an example of what we observe as a cavity 14 in core, what a cavity looks like when you encounter 15 it in a boring program.
16 And when you open up the core box, that's 17 what it is. It's a piece of round foam that says, "no 18 recovery" on it and a boring log that documents the --
19 MEMBER BROWN: Well, somebody put the foam 20 in, I guess, when they open it up, right?
21 (Laughter.)
22 MEMBER BROWN: I'm sorry, you got to have 23 humor in here somewhere. Okay. I understand what you 24 meant. I couldn't see that when you were talking 25 about it.
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102 1 MS. THOMPSON: Okay.
2 MEMBER BROWN: Thank you.
3 MS. THOMPSON: If there are no other 4 questions, I'll introduce my colleague --
5 CHAIRMAN KIRCHNER: Would you -- again, a 6 slide like this is very informative, but is it 7 directly relevant? So, yes, you find cavities, karst 8 you identified as a major issue.
9 Would you agree with the Applicant that 10 most of the cavity formation is probably closer to the 11 surface than the depth of the foundation that they 12 plan to use for the actual site?
13 MS. THOMPSON: In general, you will have 14 larger and more frequent cavities closer to the 15 surface.
16 CHAIRMAN KIRCHNER: Okay. Are you going 17 to talk to their analysis with PLAXIS?
18 MS. THOMPSON: That will be addressed by 19 our geotechnical engineer.
20 CHAIRMAN KIRCHNER: Okay. Good. I'll 21 wait then. Thank you.
22 MS. THOMPSON: So, I will pass the pointer 23 on to Dr. David Heeszel for vibratory ground motion.
24 DR. HEESZEL: Good afternoon. My name is 25 David Heeszel. I was the lead reviewer for Section NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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103 1 2.5.2, Vibratory Ground Motion.
2 Next slide. So, some key topics of review 3 for Section 2.5.2 was the Applicant's treatment of the 4 Eastern Tennessee seismic zone, the Applicant's 5 approach to developing its site response inputs, and 6 its 2D site response sensitivity study.
7 So, the Eastern Tennessee seismic zone is 8 a region outlined in green here of elevated seismicity 9 rates relative to the background rate and rest of --
10 the majority of the rest of the eastern United States.
11 The magnitudes are quite small, magnitudes 3, there's 12 a couple 4s.
13 These earthquakes generally occur within 14 the basement rocks, so within the granitic bedrock 15 beneath the sedimentary section that we spent all of 16 this time talking about. So, they're quite deep 17 relative to what we've been discussing previously.
18 The Eastern Tennessee seismic zone is 19 included within NUREG-2115, the CEUS SSC. It's 20 included both within our seismic tectonic zones and 21 within the Mmax source zones.
22 Sensitivity studies were done at the time 23 of the NUREG-2115 to ensure that the Eastern Tennessee 24 seismic zone was adequately captured by the models as 25 they were developed; however, there's been a couple of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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104 1 recent geologic studies that have interpreted the 2 potential based on some trenching work and some field 3 mapping for potentially large earthquakes, magnitude 4 greater than 6 1/2.
5 Next slide.
6 MEMBER RICCARDELLA: Is that subsequent to 7 NUREG-2115, that recently?
8 DR. HEESZEL: It's subsequent, yes.
9 Next slide.
10 CHAIRMAN KIRCHNER: Let's go back to that 11 slide.
12 When you put something down like that, 13 that, for the public, would raise questions, I would 14 think.
15 DR. HEESZEL: Exactly. I'm going to 16 address them.
17 CHAIRMAN KIRCHNER: So, you're going to 18 address the --
19 DR. HEESZEL: Yeah.
20 CHAIRMAN KIRCHNER: But in terms of 21 notwithstanding potential, but based on measurements 22 where you have a lot of data, it seems to me, not 23 surprisingly, it's -- and I'm not a geologist, so I 24 may not be using correct clinical terminology, it 25 looks like this is active, that's not surprising given NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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105 1 the geology, but the magnitudes that have been 2 measured are, on the average, quite low.
3 DR. HEESZEL: That's correct.
4 So, if you look at this slide here, you 5 can't quite see the --
6 CHAIRMAN KIRCHNER: Well, we can read it 7 from your view of --
8 DR. HEESZEL: Yeah.
9 CHAIRMAN KIRCHNER: Yes.
10 DR. HEESZEL: So, you know, there's, what, 11 two magnitude 5 -- between 5 and 6 over here; but 12 within the Eastern Tennessee seismic zone you're 13 looking at 3s and 4s.
14 CHAIRMAN KIRCHNER: So, you have not -- in 15 the past, you've never seen something six or greater?
16 DR. HEESZEL: No, not within --
17 CHAIRMAN KIRCHNER: And we make large 18 arguments about how this is geologically aged 280 19 million years.
20 What would -- what is the potential for 21 newer seismic activity of such a magnitude?
22 DR. HEESZEL: Background tectonic 23 stresses.
24 CHAIRMAN KIRCHNER: But that's true almost 25 everywhere you have a fault and --
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106 1 DR. HEESZEL: And that's why Mmaxes within 2 the entire central and eastern United States account 3 for the potential for large earthquakes.
4 CHAIRMAN KIRCHNER: Okay. And that 5 frequency would be what?
6 DR. HEESZEL: On the order of which 7 frequency?
8 CHAIRMAN KIRCHNER: 6.5 or greater.
9 DR. HEESZEL: It was suggested within 10 120,000 years, I believe.
11 CHAIRMAN KIRCHNER: 10 to the minus fifth.
12 Okay.
13 MEMBER RAY: What did you say?
14 MEMBER RICCARDELLA: 10 to the minus 5th.
15 MEMBER RAY: Yeah. Well, I come from a 16 different part of the country where the continued 17 escalation of the potential doesn't seem to ever stop.
18 CHAIRMAN KIRCHNER: Yeah. That's my 19 concern. It's kind of an open-ended item here, unless 20 there is more explanatory information.
21 Is it speculative or is it --
22 DR. HEESZEL: The geologic studies are 23 quite preliminary and the interpretations vary widely 24 amongst different experts about what the source for 25 the geologic features is.
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107 1 CHAIRMAN KIRCHNER: Just caution, in 2 general, that's a declarative statement there. That's 3 not -- that's suggestive of a much higher seismic 4 risk.
5 DR. HEESZEL: And that's what the recent 6 geologic study has -- that's their assertion.
7 CHAIRMAN KIRCHNER: And that recent study 8 has been reviewed and considered as a reasonable 9 conclusion?
10 DR. HEESZEL: It is one possible 11 interpretation for the field notes.
12 CHAIRMAN KIRCHNER: Okay. Well, I'm 13 just, in a different way, voicing Harold's concern 14 that when you put that on the table, then there's the 15 danger of ever escalating the design-basis earthquake 16 that you're designing the plant for.
17 Okay. I've made my point. Thank you.
18 DR. HEESZEL: Next slide, please.
19 So, in response to this recent geologic 20 data, the Applicant performed two sensitivity studies 21 following SSHAC guidance for a Level 2 study.
22 The first study, they evaluated the 23 Mmaxes; and then the second study, they evaluated the 24 magnitude-frequency relations.
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108 1 the proposed Mmax values developed by these -- or 2 suggested by these recent geologic studies and, in 3 fact, give a large amount of weight to magnitudes that 4 are consistent or larger than what has been suggested.
5 MEMBER RICCARDELLA: But they were further 6 away, right? As I understand, you know, the Mmaxes --
7 the big high ones are just -- they're not specifically 8 within the zone, are they?
9 DR. HEESZEL: Within each zone there's a 10 set of Mmax values that are established. So, within 11 the PEZ, the Paleozoic Extended Zone, the zone that 12 the Clinch River site and Eastern Tennessee sit 13 within, there is a suite of Mmaxes, a range. And that 14 range encompasses the range that has been recently 15 suggested.
16 In addition, the recurrence of these 17 large-magnitude events that's in NUREG-2115, if you 18 look at the NUREG-2115, the recurrence rates for 19 magnitude 6 1/2 and 7s is on the order of 13,000 to 20 88,000 here. So, again, within the same range of 21 values as has been suggested recently.
22 And so, you know, based on the fact that 23 the Mmax values are consistent and the frequency of 24 recurrences is consistent, staff has concluded that 25 NUREG-2115 adequately captures our current NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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109 1 understanding of the seismic hazard in the Eastern 2 Tennessee seismic zone.
3 Next slide. This slide simply shows 4 staff's confirmatory PSHA calculations at three 5 frequencies compared to the Applicant's. Applicant's 6 are solid; staff's are dotted. You can see at 10 to 7 the minus 4 and 10 to the minus 5 there's very good 8 agreement.
9 Next slide.
10 MEMBER BALLINGER: I'd like to be a little 11 bit more blunt.
12 DR. HEESZEL: Okay.
13 MEMBER BALLINGER: Back on Slide 26, that 14 statement, recent geologic studies interpret --
15 MEMBER CORRADINI: Is your microphone on?
16 MEMBER BALLINGER: I did -- it's on.
17 Okay. So, there's that statement. And then on two 18 slides later -- no. No. Excuse me. One slide later, 19 the bottom on, that implies to me that you folks have 20 done a study because the recent geologic studies 21 interpret potential for larger than 6.5. Now, you say 22 that the staff concludes.
23 So, this study was done after 2115?
24 DR. HEESZEL: That's right.
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110 1 conclude that 2115 does adequately capture the events 2 that would be greater than 6.5?
3 DR. HEESZEL: The study proposes that 4 there is the potential for large events. Our 5 conclusion is that the NUREG adequately captures the 6 potential for large events.
7 MEMBER BALLINGER: Oh, okay. Okay.
8 CHAIRMAN KIRCHNER: Another way to say it 9 would be at brackets, that potential.
10 DR. HEESZEL: But it bounds.
11 CHAIRMAN KIRCHNER: Okay.
12 MEMBER RICCARDELLA: But still I'd like to 13 get back to this distance.
14 As I recall -- I reviewed 2115 several 15 years ago -- the big, large-magnitude earthquakes were 16 pretty far away from this Tennessee --
17 DR. HEESZEL: You're talking about the 18 RMLEs like in Charleston or in --
19 MEMBER RICCARDELLA: And near Detroit. I 20 think there was one near Detroit, right, or --
21 DR. HEESZEL: New Bridge, Charleston, 22 Charlevoix --
23 MEMBER RICCARDELLA: Is that where these 24 recent geologic studies are talking about or --
25 DR. HEESZEL: No. No.
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111 1 MEMBER RICCARDELLA: -- are they talking 2 about right in that geologic --
3 DR. HEESZEL: Right in here. Sorry.
4 Right in this -- I believe it is in the little box, 5 this little black box that is barely visible.
6 MEMBER RICCARDELLA: Okay. Although, the 7 data showed that the largest was about five, right?
8 DR. HEESZEL: Say again?
9 MEMBER RICCARDELLA: The data shows that 10 the largest --
11 DR. HEESZEL: The seismicity data shows 12 magnitude 5s, yeah.
13 MEMBER RICCARDELLA: Okay.
14 MEMBER RAY: Well, in all cases, we're 15 talking about recurrence interval or probability.
16 MEMBER RICCARDELLA: Yeah.
17 MEMBER RAY: And so, there's no capping of 18 the size that could conceivably occur. The issue is, 19 do we have the recurrence interval of a large 20 earthquake correct, and they're saying they think 2115 21 still does it.
22 Okay? I mean, is that -- do you agree?
23 DR. HEESZEL: Yes.
24 MEMBER RAY: All right.
25 DR. HEESZEL: All right. Site response.
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112 1 So, the Clinch River site has a significant dip in the 2 subsurface approximately 30 degrees. We've discussed 3 it previously.
4 It has relatively high seismic velocities 5 greater than 5,000 to greater than 10,000 feet per 6 second.
7 Just for a reference frame, basement 8 crystalline rock is considered about 9200 feet per 9 second. So, you're talking about - you know, for 10 sedimentary rock it's quite fast.
11 CHAIRMAN KIRCHNER: So, hard rocks.
12 DR. HEESZEL: Hard rocks. If you're not 13 careful, you'll hit yourself in the head when you 14 swing your rock hammer at it.
15 So, the Applicant developed site response 16 inputs using three profiles in each of its two 17 locations. And the base case profile was developed 18 using log mean seismic velocity as a function of 19 depth.
20 So, if you go down 50 feet, you take all 21 of your data for 50 feet, calculate the log mean, and 22 you calculate an upper and lower profile based on the 23 standard deviation of that log with the statistical 24 variation.
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113 1 have Unit A right next to Unit B, with the dip, you're 2 going to smear those units together. So, you're going 3 to discard some of your geologic information in favor 4 of your geophysical information.
5 And so, the staff requested that the 6 Applicant explain how the use of these multiple-phase 7 cases accounts for the dip across the site.
8 The Applicant's response was that the 9 smearing of the units, using their approach, is 10 appropriate because you're maintaining both the mean 11 and the range of values as a function of depth.
12 If you think about your plant that crosses 13 boundaries, it's going to sense both units in 14 accordance with how much of those units it's on top 15 of. And so, the stratigraphic variations, the dip, is 16 accounted for.
17 Staff performed its confirmatory site 18 response by considering the dip explicit. So, if you 19 think about, from left to right, you have an up 20 section, a middle and a down section profile.
21 In addition, the staff truncated its 22 profiles at the top of the Knox unit as it's over a 23 kilometer thick and it has a velocity of greater than 24 three kilometers per second. So, it's basically 25 basement rock from a geologic -- or seismological NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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114 1 perspective.
2 And as you'll see on the next slide, 3 staff's overall results are consistent with the 4 Applicant's.
5 And so, this shows staff's confirmatory 6 GMRS in red, and the Applicant's in blue, and it's 7 just shown for reference. And the dotted black is if 8 you just consider the hard rock GMRS, you know, it's 9 a hard rock site. Just make that assumption.
10 MEMBER CORRADINI: Maybe I don't 11 understand what you mean by the staff's GMRS.
12 How did you come to that? By a separate 13 calculation or just --
14 DR. HEESZEL: We did an independent 15 confirmatory analysis using our base rock seismic 16 hazard curves that I showed a few slides ago involved 17 with site response that we developed in-house.
18 MEMBER CORRADINI: So, you used generic 19 curves that you showed on Slide 28?
20 DR. HEESZEL: Yeah. The base rock hazard 21 curves for the site that we developed for -- on Slide 22 28.
23 MEMBER CORRADINI: Thank you.
24 DR. HEESZEL: And as you can see --
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115 1 generic. They are specific to that latitude and 2 longitude, those basement rock hazard curves.
3 And then on top of that, we do the site 4 response and develop hazard at various elevations 5 beneath the site.
6 MEMBER CORRADINI: Okay. Thank you.
7 MEMBER RICCARDELLA: For the record, I 8 also compared those to the new GMRS for the Sequoyah 9 site and these are very, very close to the new --
10 DR. HEESZEL: I mean, we did a similar 11 analysis through the 2.1 process for the other sites.
12 MEMBER RICCARDELLA: Yeah.
13 DR. HEESZEL: And, as you can see, staff 14 and applicant's GMRSes are very similar indicating 15 that the differences in our approach to site response 16 are -- don't change this overall answer.
17 Next slide.
18 DR. MUNSON: Just to add one thing --
19 David, could you go back?
20 CHAIRMAN KIRCHNER: Just state your name, 21 please.
22 DR. MUNSON: Cliff Munson. I'm the senior-23 level advisor.
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116 1 response at all, that's the GMRS you get.
2 So, of this wrangling about 1D versus 2D 3 versus dipping layers, really, it doesn't have that 4 big of an impact if you look at the dotted curve.
5 So, in the end, this is an extremely hard 6 rock site that - the impedance contrasts are very 7 small.
8 DR. HEESZEL: Okay. Next slide.
9 MR. CAMPBELL: And Dr. Munson is the 10 senior-level advisor for siting for NRO.
11 MEMBER CORRADINI: Can you go back, 12 because I wanted -- I agree with you that they don't 13 look that different. But if I take the blue versus 14 the dots or the red, the fact that at high frequency 15 the Applicant's blue is a little bit lower comes from 16 the very fact of the next slide which shows at high --
17 what am I trying to say -- at high frequency they are 18 slightly below the 1D.
19 What I'm trying to understand is -- I 20 understand what you're getting at is you're saying if 21 you just take a monolithic, hard rock site, it's close 22 enough for government work, right?
23 But I was just trying to -- when I was 24 asking this of the Applicant, I was trying to 25 understand 1D versus 2D calculations and it's all at NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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117 1 high frequency.
2 MR. CAMPBELL: "Close enough for 3 government work" isn't the right word.
4 (Laughter.)
5 MR. CAMPBELL: Close enough for the 6 purposes of characterizing the site for the ESP.
7 DR. MUNSON: And I think that the slight 8 dip you see in the high frequency might be due to the 9 Applicant using a slightly higher damping.
10 DR. HEESZEL: Slightly higher damping and 11 differences in interpolation algorithms, you know.
12 MEMBER RICCARDELLA: Because my 13 understanding is the Applicant used 1D analysis.
14 DR. HEESZEL: Yes.
15 (Simultaneous speaking.)
16 MEMBER RICCARDELLA: He just did the 2D 17 for comparison to show that the 1D was conservative.
18 DR. HEESZEL: Next slide. So, the 19 Applicant, as we've discussed, has performed a 2D site 20 response sensitivity study due to the relatively high 21 dip in the subsurface.
22 Reg Guide 1.208 specifically called out 23 this potentiality if there's a complicated subsurface 24 structure, a multidimensional approach may be 25 necessary.
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118 1 In response to that, the Applicant 2 developed this 2D analysis. Initially, the 2D 3 analysis compared -- so, the blue line to a suite of 4 lines that were developed using the same inputs that 5 were developed for the 2D response, staff requested 6 that they compare to the 1D response used for the 7 licensing basis.
8 And the result is this graph here on the 9 right, which satisfied staff's concern that the 2D 10 results account for -- or the 1D results, excuse me, 11 account for 2D structure using the site response 12 inputs that are used in the GMRS development.
13 Next slide. So, staff's conclusions. The 14 Applicant provided thorough characterization of the 15 seismic sources surrounding the site as required by 10 16 CFR 100.23.
17 The Applicant adequately addressed the 18 uncertainties inherent in that characterization 19 through the use of a PSHA, and the PSHA follows 20 guidance provided in Reg Guide 1.208.
21 Finally, the Applicant's GMRS adequately 22 represents the regional and local seismic hazards and 23 accurately includes the effects of the local site 24 subsurface properties.
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119 1 will pass the baton to my colleague Luissette 2 Candelario.
3 MEMBER RICCARDELLA: Is it the 4 anticipation that in addition to designing this GMRS 5 that at COL time there will also be a seismic PRA 6 considering all frequencies?
7 I mean, at some point I would assume 8 there'd be -- or a seismic margins analysis?
9 DR. HEESZEL: That is part of the Part 52 10 process.
11 MEMBER CORRADINI: But I want to make sure 12 that I understood it could be either. It wouldn't 13 have to be a probabilistic seismic analysis, it could 14 be a --
15 MEMBER RICCARDELLA: SMA.
16 MEMBER CORRADINI: What is --
17 MEMBER RICCARDELLA: Seismic margins 18 analysis.
19 MEMBER CORRADINI: Seismic margin 20 analysis.
21 DR. MUNSON: Now, before fuel loading, 22 they have to do a seismic PRA. A seismic margin is 23 done for the design certification, but for the site-24 specific COL before fuel loading, once they receive 25 license, they have to do a seismic PRA.
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120 1 MEMBER RICCARDELLA: Okay. Thank you.
2 MEMBER CORRADINI: Thanks for the 3 clarification.
4 MS. CANDELARIO: Thank you, Dr. Heeszel, 5 and good afternoon.
6 My name is Luissette Candelario, and I was 7 one of the technical reviewers for Section 2.5.4, 8 Stability of Subsurface Materials and Foundations, and 9 Section 2.5.5, which is Slope Stability Analysis.
10 My colleague, Dr. Weijun Wang in the 11 audience, was also involved in the review of these 12 sections.
13 This slide presents a summary of SAR 14 Section 2.5.4 and the key areas reviewed by the staff.
15 SAR Section 2.5.4 present the individual properties of 16 subsurface materials and evaluation of stability of 17 subsurface materials and foundation at the site.
18 SAR Section 2.5.4 includes the staff 19 review of the Applicant field and laboratory 20 investigations data and associated assumptions and 21 calculations used to determine the geotechnical 22 properties of materials at the site.
23 The staff also review the relationship of 24 foundations and underlying materials, descriptions of 25 your physical investigation performed at the site and NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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121 1 the result of same.
2 The excavation and backfill, groundwater 3 conditions, response of soil and -- dynamic loading, 4 liquefaction potential and stability of foundations.
5 SAR Section 2.5.4 also includes 16 COL 6 action items and one permit condition, which I will 7 explain in detail in the upcoming slides.
8 In order to provide sufficient 9 geotechnical information of the site without having a 10 specific design, the Applicant provided a surrogate 11 design in its application.
12 The surrogate plant approach covered a set 13 of bounding parameters also known as the plant 14 parameter envelope or PPE.
15 Under the PPE approach, the resulting ESP 16 will be applicable for a range of reactor designs if 17 the relevant design parameters falls into the PPE.
18 Section 2.5.4, PPE site characteristic, 19 includes a minimum bedding capacity of 110 kips per 20 square foot, a minimum shear-wave velocity of 4,650 21 feet per second, no liquefaction, and the deepest 22 foundation embedment depth of 138 feet from the 23 finished grade.
24 This slide present a site layout and a 25 boring location plan at the Clinch River site. The NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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122 1 figure provides the bounding power block area 2 associated with the plant parameter envelope.
3 The Clinch River site subsurface 4 investigation included 82 borings with depth of about 5 20 feet to 540 feet.
6 Seven of the borings were drilled at 7 inclinations between 25 and 29 degrees from the 8 vertical.
9 The Applicant performed three test pits, 10 44 observation wells, two surface geophysical tests, 11 and rock pressuremeter tests in two borings. The 12 Applicant performed downhole geophysical tests in 28 13 borings.
14 Next slide. This slide shows a cross-15 section of a bedrock structure and the stratigraphic 16 unit of the site underneath the power block area.
17 The area bounded by the green lines shows 18 the -- foundation level that the Applicant considered 19 for the power block area.
20 The Applicant considered foundation 21 embedment depth of 80 feet and 138 feet below plant 22 grade. Bedrock is encountered approximately between 23 20 and 30 feet below the existing ground surface.
24 The average of the existing site elevation 25 in the power block area is about 810 feet. The NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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123 1 Applicant use a finish plan rate elevation of 821 feet 2 from the power block area -- for the power block area.
3 The groundwater generally occurs at depths 4 ranging from near surface to approximately 25 feet.
5 The average dip of the bedding plane is about 33 6 degrees southeast, and, as you can see, it doesn't 7 change considerably between layers.
8 Because of this dipping bed at the site, 9 various stratigraphic units may be exposed at the 10 foundation level at different locations within the 11 power block area.
12 The implications of this geologic feature 13 for the evaluation of bedding capacity and sediment 14 will be explained in the upcoming slides.
15 Next slide. One of the key review topics 16 of interest is the assessment of the effect of 17 underground voids on foundation stability.
18 As Jenise and Gerry point out, karst 19 exists at the Clinch River site and the underground 20 voids may adversely affect the foundation stability.
21 The Applicant site investigation provided 22 preliminary information on void distribution and size.
23 The Applicant data shows that cavities are present in 24 all stratigraphic unit of the site, but are more 25 predominant in the Rockdell Formation and Eidson NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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124 1 Member.
2 These cavities ranges from one feet to 3 about 17 feet in height and includes open and clay-4 filled voids and are predominantly found within the 5 first hundred feet from the ground surface.
6 The staff review the Applicant's PLAXIS 2D 7 finite element analysis that assess the effect of 8 postulated underground voids on foundation stability 9 at the Clinch River site.
10 The staff review of the analysis focus on 11 assessing the suitability of the site related to the 12 critical size of a cavity that can affect foundation 13 stability.
14 The 2D finite element model consider 15 actual site conditions based on information obtained 16 from the site investigation.
17 The diameter of the maximum void was 18 assumed based on boring data, and the length of the 19 void was conservatively assumed to be infinity.
20 Locations of the maximum voids were 21 assumed at the most critical locations where the 22 materials is the weakest and stress induced by 23 structures is the highest.
24 Next slide. Another key review topic of 25 interest is the foundation stability analysis with NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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125 1 inclined strata.
2 The Clinch River site consists of multiple 3 incline layers of various rock formation with possible 4 weakened interfaces between the formations.
5 The staff review the Applicant's multiple 6 traditional methods and finite element method used to 7 assess foundation stability at the Clinch River site.
8 The Applicant used different traditional 9 methods to obtain a range of calculated values and to 10 identify which method is more suitable for the site.
11 The staff noted that traditional methods 12 for the evaluation of foundation stability, such as 13 bedding capacity and sediment, are based on 14 assumptions of flat layers, either half-space 15 (phonetic) uniform material, or layered uniform 16 material. Therefore, the suitability of the 17 traditional methods needed to be evaluated.
18 As such, the Applicant developed a two-19 dimensional finite element model to estimate the 20 bedding capacity and sediment. The analysis modeled 21 the actual site geologic conditions based on the site 22 investigation data.
23 The staff concludes that the traditional 24 method's results are in good agreement with those 25 obtained from the finite element model and that the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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126 1 selected PPE values related to the site stability 2 analysis are appropriate.
3 The staff identifies COL Action Item 2.5-4 12 through 2.5-14 for the COL or CP applicant to 5 address the foundation stability of the site once a 6 reactor technology and a specific location and extent 7 of the seismic category I structure is identified.
8 Next slide. The Applicant used a PPE 9 instead of a specific plant design. As such, seismic 10 category I structures for the proposed site are not 11 identified and the specific location and extent of the 12 structure is not known at the ESP stage.
13 As such, the staff identify COL Action 14 Item 2.5-1 through 2.5-16 that specifies that the 15 reactor technology and site location-specific actions 16 needed to be addressed by the COL or CP applicant when 17 referencing this ESP.
18 Those COL action items are related to the 19 following site characteristics: Site geologic 20 features, properties of subsurface materials, 21 excavation and backfill, groundwater conditions, 22 static and dynamic stability, design criteria, and 23 techniques to improve subsurface conditions.
24 The staff identified permit condition two, 25 to ensure that the material above elevation 741 feet NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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127 1 in areas where safety-related structure would be 2 located are removed to minimize the adverse effect of 3 discontinuities, weather and shear-fracture zones, and 4 karst features on the stability of subsurface 5 materials and foundations.
6 And that additional geotechnical 7 investigations are performed at the excavation level 8 to identify any potential geologic features that may 9 adversely impact the stability of subsurface materials 10 and foundations.
11 MEMBER CORRADINI: I want to make sure I 12 understand this condition. So, this says that 13 regardless of the design chosen, if it's chosen for 14 this area, they have to excavate down to 741 feet, 15 which is how much above the surface?
16 MS. CANDELARIO: 80 feet is the shallowest 17 embedment considered by the Applicant.
18 MEMBER CORRADINI: Thank you. At least?
19 MS. CANDELARIO: At least.
20 The staff concludes that the Applicant 21 adequately determined the site-specific engineering 22 properties of subsurface materials underlying the 23 Clinch River site and conducted sufficient evaluation 24 of the stability of subsurface materials and 25 foundations based on the result of field and NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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128 1 laboratory tests and the state-of-the-art methodology 2 and in accordance with Regulatory Guides 1.1-32, 1.1-3 38 and 1.1-98.
4 The staff concludes that the Applicant 5 meets the requirements of 10 CFR Part 52.17(a)(1)(vi) 6 and 10 CFR Part 100.23(c) for this ESP application 7 regarding the stability of subsurface materials and 8 foundations.
9 Any questions?
10 (No questions.)
11 MS. CANDELARIO: So, Sections 2.5.5 12 discuss the stability of slopes. Next slide. The NRC 13 staff reviewed SSAR Section 2.5.5 which provide 14 general descriptions of site related to slope 15 stability analysis.
16 There are no existing slope on the site at 17 this time, either natural or manmade, that could 18 affect the stability of the site.
19 The Applicant deferred the actual slope 20 stability analysis to the COL or CP application. In 21 order to address the need for future slope stability 22 analysis, the staff identified COL Action Item 2.5-15, 23 which specifies that an applicant for a COL or CP 24 application that references these early site permit 25 should perform a slope stability analysis of any NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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129 1 safety-related slopes, including dams and dikes, 2 consistent with the selected reactor technology.
3 Next slide. The staff conclude that the 4 Applicant provided unnecessary information on site 5 topography and geologic characteristic and adequately 6 described the slope's characteristic at the site.
7 The staff conclude that the SSAR Section 8 2.5.5 is adequate and acceptable because it meets 9 applicable requirements of 10 CFR Part 50 Appendix S, 10 10 CFR Part 52.17(a)(1)(vi) and 10 CFR Part 100.23.
11 Any questions?
12 CHAIRMAN KIRCHNER: Questions? Members?
13 (No questions.)
14 CHAIRMAN KIRCHNER: Well, I think we 15 should now turn to any members of the public who wish 16 to make a comment.
17 Anyone present in the audience?
18 (No questions.)
19 CHAIRMAN KIRCHNER: Can we now turn to our 20 phone connection, please.
21 OPERATOR: The conference is now in talk 22 mode.
23 CHAIRMAN KIRCHNER: If there are any 24 members listening in who wish to make a comment, 25 please identify yourself and make your comment.
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130 1 (No comments.)
2 CHAIRMAN KIRCHNER: Hearing none --
3 MEMBER BLEY: You said members?
4 CHAIRMAN KIRCHNER: Oh, excuse me, Dennis.
5 That sounds like a familiar voice. Please go ahead.
6 MEMBER BLEY: Okay. Well, I assume you're 7 doing our round now and --
8 CHAIRMAN KIRCHNER: Yes.
9 MEMBER BLEY: (Telephonic interference) 10 presentation revises the questions, but I don't have 11 anything to add.
12 CHAIRMAN KIRCHNER: Thank you, Dennis.
13 Members?
14 (No questions.)
15 CHAIRMAN KIRCHNER: Let me then thank both 16 the Applicant and the staff for very good 17 presentations. And with that, we are adjourned.
18 (Whereupon, the above-entitled matter went 19 off the record at 3:51 p.m.)
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Clinch River Early Site Permit Part 2, SSAR Section 2.5 Advisory Committee on Reactor Safeguards Committee Meeting Presented by Ray Schiele, Licensing Wally Justice, Engineering October 17, 2018
Acknowledgement and Disclaimer Acknowledgment: "This material is based upon work supported by the Department of Energy under Award Number DE-NE0008336."
Disclaimer: "This presentation was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof."
Advisory Committee on Reactor Safeguards l 2
TVAs Mission Serving the people of the Tennessee Valley to make life better.
Energy Environment Economic Development Partner with 154 local power companies, to serve more than 9 million customers in parts of seven states. Directly serve 54 large industries and federal installations.
Advisory Committee on Reactor Safeguards l 3
NRC Review of ESPA 2017 2018 2019 2020 ESPA ESPA Rev. 1 ESPA Rev. 2 FEIS FSER NRC Issues Accepted Submitted Planned Submittal ESP 12-30-16 12-15-17 Dec 18 Safety Review PSER SER w/ no OIs 8/4 10/20 FSER 8/17 Full ACRS Audits & RAIs 5/15 8/22 10/17 11/14 12/5 ACRS Subcomm. Meetings Scoping Environmental Review Meeting 5/15 Comment Period FEIS 6/21 Notice of Intent Audits & RAIs DEIS 4/13 4/26 4 Contentions 2 Contentions Commission Hearing(s)
Filed Admitted Ruling 6/12 10/10 5/3 Notice of Hearing, Commission Hearing Opportunity TVA ASLB Contested 4/4 Appeals Ruling Hearing Advisory Committee on Reactor Safeguards l 4 11/6 7/31 Terminated
Key NRC Interactions Related to ESPA SSAR Section 2.5 Two audits and one management/geologist visit were conducted to review the geology, seismology, and geotechnical information in the ESPA Pre-Application Readiness Assessment - September 15-17, 2015 68 specific actions identified for resolution prior to application submittal January 13, 2016 Public Meeting to discuss TVAs incorporation of issues in the application Audit - May 8-9, 2017 Office discussion General presentation of the Clinch River site Discussion and response to specific NRC Audit Information Needs regarding Geologic Information, Vibratory Ground Motion, and Geotechnical Engineering Site Tour Tour site and site vicinity geologic features Review core samples 6 specific areas where supplemental info was requested (part of RAIs)
Management Visit - January 30-31, 2018 Office discussion Site Tour Advisory Committee on Reactor Safeguards l 5
Presentation Outline Part 2, Site Safety Analysis Report (SSAR), Section 2.5, Geology, Seismology, and Geotechnical Engineering:
Geology - Wally Justice, SMR Engineering ,Kevin Clahan, LCI, Janet Sowers, Fugro Seismology - Wally Justice Geotechnical Engineering - Wally Justice Advisory Committee on Reactor Safeguards l 6
ESPA Part 2, SSAR Section 2.5 Geology Advisory Committee on Reactor Safeguards l 7
SSAR Section 2.5 - Geology The geological and seismological information presented in this subsection 2.5.1 was developed from a review of previous reports for the proposed Clinch River Breeder Reactor, published geologic literature, and interpretations of data obtained as part of the surface and subsurface field investigations.
Complies with the requirements of 10 CFR 100.23(c).
The geological information was developed in accordance with NRC guidance documents Regulatory Guide (RG) 1.206 NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition, Section 2.5.1, provides guidance for the development of Subsection 2.5.1.
Advisory Committee on Reactor Safeguards l 8
Clinch River Site Regional Description Advisory Committee on Reactor Safeguards l 9
Local Physiography Bedrock physiography is characterized by a well-developed valley and ridge system.
Advisory Committee on Reactor Safeguards l 10
Regional Distribution of Carbonate Rocks Advisory Committee on Reactor Safeguards l 11
Geological Cross Section of Clinch River Site Advisory Committee on Reactor Safeguards l12
Field and Data Investigations
- Field Reconnaissance
- Geomorphic analyses/LiDar digital elevation data
- Previous Clinch River Breeder Reactor data and investigations (70s -80s)
- Core Borings
- Oak Ridge National Laboratory reports
- Geologic publications
- Karst mapping
- River-terrace mapping Advisory Committee on Reactor Safeguards l 13
Field Reconnaissance Waypoints - Regional and Site Area Advisory Committee on Reactor Safeguards l 14
LiDAR Digital Elevation Model Coverage Advisory Committee on Reactor Safeguards l 15
Core Borings of CRBR Project Advisory Committee on Reactor Safeguards l 16
Borehole Locations at Site A and B Core Borings
- 76 rock borings performed for the SMR project
- 104 borings performed for the Clinch River Breeder Reactor Project B
Old CRBR Footprint A
Advisory Committee on Reactor Safeguards l 17
Faults Two Faults traverse the Clinch River Site Location
- Copper Creek Fault
- Chestnut Ridge Fault No evidence of deformation within the Quaternary time period Advisory Committee on Reactor Safeguards l 18
Shear Fracture Zone Schematic diagram of relationship between Bedding, Styolites, and Shear-Fracture Zones Cross-section through Shear-Fracture Zones Advisory Committee on Reactor Safeguards l 19
Shear Fracture Zone Core Boring Photograph Photograph of Boring MP-101
- Shear-Fracture Zone is very small
- Not a fault breccia
- Resulted from strain relief during the Alleghanian orogeny Advisory Committee on Reactor Safeguards l 20
Local Geologic Hazards
- Karst features and active processes are common throughout the site
- Sinkholes, springs, underground drainage and irregular soil-bedrock contact
- Karst conditions are the primary geologic hazard of concern for this application Advisory Committee on Reactor Safeguards l 21
Karst Model Example
- In summary, karst models show that dissolution occurs in a variety of hydrogeologic settings.
- Epigenetic dissolution, by descending and circulating meteoric water, can occur in the vadose zone, in the shallow phreatic zone, and in the deep phreatic zone.
- A karst model for the CRN Site, informed by the above discussions, is shown on a following slide.
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Karst-related studies
- Multiple karst studies performed for the Oak Ridge Reservation were utilized, including karst inventories and ground water flow testing
- Karst studies performed for the Clinch River Breeder Reactor Project were utilized, including information from core borings
- Recent studies included LiDAR mapping of karst features, compilation of core boring information, analysis and modeling Advisory Committee on Reactor Safeguards l 23
Karst Study Conclusions
- The dominant orientation of phreatic dissolution pathways is strike-parallel. Groundwater flow is constrained by low-carbonate units, resulting in strike-parallel drainage systems
- The Fleanor, Blackford, and Bowen formations, the most carbonate-poor units in the Chickamauga Group, have no mapped sinkholes and smaller and fewer borehole cavities than other units.
- Borehole data show that subsurface dissolution is most intense near the surface and decreases steadily with depth. Small numbers of cavities are observed below the water table indicating deep pheratic dissolution has occurred. This is consistent with observations of decreased fracturing frequency and groundwater flowrates with depth in the ORR studies
- Direct evidence of hypogene dissolution processes is not documented at the CR Site or within the ORR. Most evidence is consistent with dissolution by epigenetic processes in the vadose and phreatic zones. This evidence includes the decrease in frequency of fractures and dissolution cavities with depth in boreholes Advisory Committee on Reactor Safeguards l 24
Karst Model of the Clinch River Site Advisory Committee on Reactor Safeguards l 25
Clinch River Breeder Reactor Excavation Mapping circa 1983
- The excavation mapping report concluded that the site was suitable for development of the proposed facility or other industrial facilities based on the character of the rock exposed.
NUREG -0968
- The planned foundation level of the CRBRP, 714 ft MSL, was below the zone of weathered siltstone observed in the excavation, and the limestone at that elevation was found to be hard and sound. No cavities were described on the floor of the excavation.
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Geologic Investigation Conclusion
- Active faulting is not a geological hazard for the site area
- Shear fractures are not a geological hazard for the site area
- Karst conditions are identified as the potential geologic hazard for the site area
- Met regulatory requirements of 10CFR52.17 and the guidance from Regulatory Guide 1.208 Advisory Committee on Reactor Safeguards l 27
ESPA Part 2, SSAR Section 2.5 Seismology Advisory Committee on Reactor Safeguards l 28
SSAR Section 2.5 - Seismology The purpose of Subsection 2.5.2 is to determine the site-specific ground motion response spectrum (GMRS). The GMRS is defined as the free-field horizontal and vertical ground motion response spectra at the site and must satisfy the requirements of 10 CFR 100.23.
The GMRS was developed with consideration of the guidance provided in NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants Development of the ground motions for the SSAR begins with implementation of the provisions of RG 1.208, A Performance-Based Approach to Define the Site-Specific Earthquake. This regulatory guide describes acceptable methods to conduct geological, seismological, and geophysical investigations of the CRN Site and region around the site, identify and characterize seismic sources, perform a probabilistic seismic hazards analysis (PSHA), perform site response analysis, and determine the Ground Motion Response Spectra (GMRS) using a performance-based approach.
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Seismicity Plot of Regional Seismicity from the Central Eastern United States (CEUS) SSC Earthquake Catalog (2009)
Application was based on 2012 data update Advisory Committee on Reactor Safeguards l 30
Seismicity East Tennessee Seismic Zone Geometry (As Defined by USGS)
Advisory Committee on Reactor Safeguards l 31
GMRS Development - Approach Review Site Information Rock Hazard Evaluate Kappa from Observation and Damping From Lab Testing Develop Site Vs Profiles and Select Dynamic Properties Perform 2D analysis to address dipping strata Perform Site Response Analysis Using Approach 3 Calculate GMRS Review Advisory Committee on Reactor Safeguards l 32
RG 1.208 Approach 3 Description Approach 3
- Fully Probabilistic
> Preserves Hazard Levels
> Hazard at Surface computed by integration of Hard Rock Hazard with probability distribution of frequency and strain dependent factors
> Results in complete hazard curve at ground surface.
- Endorsed by NUREG CR/6728: Technical Basis for Revision of Regulatory Guidance on Design Ground Motions: Hazard- and Risk-Consistent Ground Motion Spectra Guidelines
- Basic Steps in Approach 3
> Randomization of site dynamic material properties
> Computation of amplification factors using Random Vibration Theory
> Full Integration of mean and fractile hazard curves Advisory Committee on Reactor Safeguards l 33
Geologic Cross-Section Showing Borehole Locations and VS Profiles Advisory Committee on Reactor Safeguards l 34
Geological Cross-Section with Vs Profiles Advisory Committee on Reactor Safeguards l 35
Vs Profiles for Site A and B Geologic and Velocity Geologic and Velocity Profiles for Site A Profiles for Site B Advisory Committee on Reactor Safeguards l 36
GMRS Development - Hazard at Ground Surface Mean Hazard at ground surface for the range of frequencies Advisory Committee on Reactor Safeguards l 37
GMRS Development Area A and B A B Advisory Committee on Reactor Safeguards l 38
GMRS Envelope Advisory Committee on Reactor Safeguards l 39
Comparison of the 2D and the 1D RVT Amp Factors (all basecase profiles)
A B Advisory Committee on Reactor Safeguards l 40
2D vs 1D Comparison
- The Random Vibration Theory (RVT) ID amplification factors used to calculate the GMRS significantly exceed the 2D amplification factors (smoothed) for the single time-domain sensitivity calculation across the full frequency range except at one frequency.
- 2D effects are not expected at the site because of the high shear wave velocity (VS) of the underlying rock and the small impedance contrasts between rock layers.
- The use of multiple basecase velocity profiles in calculating the GMRS are expected to accommodate any potential 2D effects.
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Seismology Conclusions
- The Probabilistic Seismic Hazard Analysis performed for the Clinch River Site, specifically Sites A and B, :
- Followed 10 CFR 100.23 and the guidance of RG 1.208
- Represents the regional and local hazards
- Includes the local subsurface properties
- Evaluated the potential for 2D effects due to dipping angle Advisory Committee on Reactor Safeguards l 42
ESPA Part 2, SSAR Section 2.5 Geotechnical Engineering Advisory Committee on Reactor Safeguards l 43
SSAR Section 2.5 - Geotechnical Engineering Information presented within these subsections 2.5.3, 2.5.4, and 2.5.5 has been developed in accordance with RG 1.208 and is intended to demonstrate compliance with 10 CFR 100.23, Geologic and Seismic Siting Criteria
- Specifically, this subsection addresses the following issues: Potential surface deformation associated with active tectonism, including any significant neotectonic features (faults).Potential surface deformation associated with non-tectonic processes such as collapse structures (karst collapse), slope failures, and anthropogenic deformation (e.g., mine collapse).
- This geological, geophysical and geotechnical information is used as a basis to evaluate the stability of subsurface materials and foundations at the CRN Site.
- The information presented in this subsection is based on the results of the site-specific subsurface investigation performed at the Clinch River Nuclear Site.
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Surface Deformation
- TVA performed geological, seismological and geophysical investigations and analysis for the region and the site
- TVA concluded in the application that the potential for tectonic deformation at the site is negligible
- Non-tectonic deformation is possible with karst conditions
- Detailed mapping of excavation walls and foundations will be performed during construction for a confirmation of the conclusions reached in the application Advisory Committee on Reactor Safeguards l 45
Stability of Subsurface Materials and Foundations
- CRBRP subsurface investigations
- Clinch River site subsurface investigations:
- 82 geotechnical core borings (includes 6 soil borings)
- 3 test pits
- 44 observation wells
- Seismic reflection and refraction tests
- Downhole geophysical testing in 28 borings
- Field permeability and pumping tests
- Groundwater level monitoring in the observation wells
- Rock pressure meter tests in two borings
- Laboratory testing of boring soil and rock samples
- These programs followed RG 1.132, Site Investigations for Foundations of Nuclear Power Plants Advisory Committee on Reactor Safeguards l 46
Engineering Properties
- Ultimate Bearing Capacity
- Allowable Bearing Capacity
- Settlement and Heave Analysis
- Additional engineering properties were also developed per regulatory requirements Advisory Committee on Reactor Safeguards l 47
Foundation Assessment Model for Karst Voids
- A PLAXIS 2D analysis was performed to demonstrate foundation acceptability
- A large PWR foundation was selected due to limited design information available for the SMRs considered in the Plant Parameter Envelope
- Finite Element Models were developed for both Site A and B
- Three embedment depths (40 ft, 90 ft and 140 ft) were evaluated
- Two different cavity depths below the foundation level were evaluated (5 ft and 30 ft) for each embedment depth
- Additionally, three locations for cavity placement were also evaluated for each of the above cases:
- At the edge of the Nuclear Island (for tipping)
- At the center of the Nuclear Island
- Along the appropriate bedding plane for the Site Advisory Committee on Reactor Safeguards l 48
PLAXIS Model Example Advisory Committee on Reactor Safeguards l 49
Foundation Model Results
- Approximately 99 percent of the cavities observed in Site A and B borings are significantly less than 11 ft in inferred height.
- Cavity development in CRN Site areas is generally limited to the most markedly weathered zone immediately below ground surface, to depths less than 100 ft; 75 percent of reported cavities in Site A and B borings occur at depths less than 55 ft which will consequently be excavated to the embedment depths of 80-140ft. Depending on the technology selected.
- Cavity-related failure has a higher potential to occur at relatively shallow depth, less than about 30 ft. Given that foundation embedment depths are deeper than 30 ft and that the 15 ft critical cavity diameter determined by PLAXIS 2D modeling is significantly larger than the 11 ft height that bounds 99 percent of the cavities observed in CRN Site borings, Sites A and B are suitable for SMR foundation.
Advisory Committee on Reactor Safeguards l 50
Foundation Model Results (continued)
- At COLA, foundation performance will be re-evaluated on selection of a final technology, taking into account specific plant design, specific plant loads, and any potential ground improvement or grouting plans.
- Final foundation locations will also be re-evaluated using specific plant information.
Advisory Committee on Reactor Safeguards l 51
Stability of Slopes
- Given the existing topography, the natural topography and the planned finished grade, a flat site with no safety-related slope is planned in the vicinity of safety-related structures.
- The stability of slopes will be evaluated during the COLA phase once a reactor technology has been selected.
Advisory Committee on Reactor Safeguards l 52
Summary
- The efforts associated with the Pre-Application Readiness Review and the site audit and visit were very helpful in ensuring that the right level of detail and supporting information was available in the Application
- The Clinch River Site is capable from a geologic and seismic perspective for the construction of a Small Modular Reactor
- The potential geological hazard, karst, is identifiable and can be mitigated through approved regulatory processes.
Advisory Committee on Reactor Safeguards l 53
Advisory Committee on Reactor Safeguards Advisory Committee on Reactor Safeguards l 54
Presentation to the ACRS Subcommittee Safety Review of the Clinch River Nuclear (CRN) Site, Early Site Permit Application Chapter 2, Section 2.5: Geology, Seismology, and Geotechnical Engineering October 17, 2018 Technical Reviewers from NRO/DLSE/RGS Gerry Stirewalt, Ph.D., P.G., C.E.G.
Jenise Thompson, M.S., PMP David Heeszel, Ph.D.
Luissette Candelario, M.E Weijun Wang, Ph.D., P.E.
October 17, 2018 1
CRN Site Audits and Site Visit
- July 17 & 18, 2013 - Site Audit: Staff visited the proposed site before the ESP application was submitted to observe the initial field activities being conducted by the applicant for collecting subsurface geotechnical and geologic data (Report ML13210A3070).
- May 8 & 9, 2017 - Site Audit: Staff visited the proposed site to discuss information derived from the continuing geologic, seismic, geophysical, and geotechnical investigations being conducted by the applicant for characterizing the site (Report ML17223A428).
- January 30 & 31, 2018 - Site Visit: Staff visited the proposed site to confirm the applicants interpretations regarding faults, shear-fracture zones, and karst features (Report ML18220A749).
October 17, 2018 2
Section 2.5.1 - Geologic Characterization Information Section 2.5.3 - Surface Deformation October 17, 2018 3
Content of CRN Site ESP SSAR Section 2.5.1 Section 2.5.1 - Geologic Characterization Information
- 2.5.1.1 - Regional Geology within 320 km (200 mi) of the site:
Physiography and geomorphic processes, geologic history and tectonic evolution, stratigraphy, tectonic setting (including distribution of seismicity and stress in the eastern U.S.), and non-tectonic geologic hazards (including karst).
- 2.5.1.2 - Local Geology within 40 km (25 mi), 8 km (5 mi), and 1 km (0.6 mi) of the site: Physiography and geomorphic processes, geologic history, stratigraphy and lithology, structural geology (including faults and shear-fracture zones), geologic hazards (including karst), and site engineering geology (including potential effects of human activities).
October 17, 2018 4
Physiographic Provinces in the CRN Site Region Parallel ridges and valleys of the Valley and Ridge province developed as a result of differential weathering and erosion of folded and faulted sedimentary rock units that occur in the province.
(Reproduced from SSAR Figure 2.5.1-1)
October 17, 2018 5
Key Geologic Features of Interest for Section 2.5.1 Regional Thrust Faults and Localized Shear-Fracture Zones
- Neither of these features is well-exposed at the surface at the site.
Staff examined them in rock core samples provided by the applicant during the site audits and site visit. Both features are generally parallel to bedding
- Thrust faults are tectonic in origin and regional structures. Shear-fracture zones are more localized and contain features of both non-tectonic and probable tectonic origin
- Staff focused on documenting that the thrust faults and the shear-fracture zones are older than Quaternary (i.e., > 2.6 Ma in age) and, consequently, pose negligible hazard for the site.
October 17, 2018 6
CRN Site Subsurface Stratigraphy, Faults, and Shear-Fracture Zones CC-B2 MP-101 (After SSAR Figure 2.5.1-30)
October 17, 2018 7
Carbonate Strata Examined by Staff during the 01/2018 Site Visit Exposure of the Fleanor Formation at the site location showing amount and direction of dip of bedding commonly seen at the CRN Site (i.e.,
about 33 degrees southeast).
October 17, 2018 8
Thrust Faults
- Thrust faults are characteristic of the Valley and Ridge Province in which the site is located and do occur in the site area. There is no surface expression of any thrust faults in the site area.
- Although not exposed at the surface, the Copper Creek and Chestnut Ridge faults are located within 1 km (0.6 mi) of the site.
- During the site audits and site visit, staff examined the Copper Creek Fault in core from Borehole CC-B2. We will look at the subsurface expression of the fault in that borehole!
October 17, 2018 9
Geologic Map Showing Locations of Thrust Faults in the Site Area Fault gouge produced by crushing and grinding of rock units due to displacement along the Copper Creek Fault is dated at 279.5
+/- 11.3 Ma. Reported displacement along the fault is 12-50 km (7.4-31 mi).
(Reproduced from SSAR Figure 2.5.1-34)
Note that the site lies between the northeast-striking, southeast-dipping Copper Creek and Whiteoak Mountain thrust faults.
October 17, 2018 10
ROCK UNIT OUTSIDE THE FAULT ZONE WITHOUT CATACLASIS FAULT GOUGE PRODUCED BY MECHANICAL CRUSHING AND GRINDING (CATACLASIS) DUE TO FAULT DISPLACEMENT BEDDING Fault gouge marking the Copper Creek Fault in Borehole CC-B2. Note the clear distinction between the gouge, dated at ~280 Ma, and intact rock. (G.
Stirewalt image, January 2018)
October 17, 2018 11
Shear-Fracture Zones
- Shear-fracture zones at the site contain pressure solution features (stylolites) oriented parallel and perpendicular to bedding. These features tell a story about orientation of stresses that affected the shear-fracture zones.
- Non-tectonic bedding-parallel stylolites (earliest) formed during deposition and lithification of sedimentary units due to vertical overburden pressures. Bedding-perpendicular stylolites (latest) likely formed in response to near-horizontal stresses related to transport of thrust sheets (~280 Ma) and suggest tectonic overprinting.
- During the site audits and site visit, staff examined the shear-fracture zone that occurs in the Rockdell Formation in core from Borehole MP-101.
October 17, 2018 12
CALCITE VEINS BEDDING-PARALLEL STYLOLITES BEDDING CALCITE VEIN STYLOLITES AT HIGH ANGLES TO BEDDING Shear-fracture zone penetrated in borehole MP-101. The stylolites must have developed at two different times because they form essentially perpendicular to the causative stress. (G. Stirewalt image, January 2018) 13
Staff's Conclusions for CRN ESP SSAR Section 2.5.1 No tectonic features with the potential for adversely affecting suitability of the site occur in the site region, site vicinity, site area or at the site location (i.e., no data suggest the presence of Quaternary tectonic features). The primary tectonic event registered in the rock units, regional thrust faults, is dated at ~280 Ma. No field evidence suggests the shear-fracture zones are younger than that event.
Karst is the primary non-tectonic feature with the potential to adversely affect suitability of the site.
The applicant described geologic characteristics of the site region, site vicinity, site area and site location in SSAR Section 2.5.1 in full compliance with regulatory requirements in 10 CFR 52.17(a)(1)(vi) and 10 CFR 100.23(c) and in accordance with guidance in RG 1.208.
October 17, 2018 14
Content of CRN ESP SSAR Section 2.5.3 Section 2.5.3 - Surface Deformation
- 2.5.3.1 through 2.5.3.8 - Information related to assessment of features that might indicate a potential for tectonic (including geologic features observed in the East Tennessee Seismic Zone) and non-tectonic (i.e., specifically karst-related features) surface deformation at the site.
October 17, 2018 15
Key Review Topics of Interest for Section 2.5.3 The staff reviewed the following key topics for the potential for tectonic and non-tectonic surface deformation at the CRN site.
- The relationship of potential tectonic surface deformation to observed seismicity in the East Tennessee Seismic Zone is undetermined.
- Due to carbonate rocks in the subsurface, direct observation of karst features and ongoing dissolution processes in site vicinity, and interpreted cavities in core as indicated by missing segments, karst has the potential to cause surface deformation at the CRN Site October 17, 2018 16
Distribution of mapped karst features in the CRN site area Swale: small wet depression Swallet: slightly larger depression through which water drains Sinkhole: surface depression as a result of subsurface collapse due to dissolution October 17, 2018 (After SSAR Figure 2.5.1-47) 17
Cavities in core from borings Borehole MP-418 Interpreted cavities of varying thicknesses recorded in numerous boreholes.
October 17, 2018 18
Pinnacle and cutter surficial karst features Dissolution features along joints and bedding planes resulting in cavities in the exposed rock October 17, 2018 19
Sinkhole within the site area with steep slope and ponded water October 17, 2018 20
Entrance to Copper Ridge Cave Copper Ridge Cave is the largest cave the staff visited in the Clinch River site area Drainage flows into the cave entrance from the surrounding depression with dissolution along joints and bedding planes, including a 90-degree turn October 17, 2018 21
Geologic Mapping Permit Condition In SSAR Section 2.5.1.2.6.10, the applicant acknowledged the need to perform detailed geologic mapping for documenting the presence or absence of karst features, faults, or shear-fracture zones in plant foundation materials.
To address this need, the staff identified Permit Condition 1 in SER Section 2.5.3.5 as stated below:
- The applicant for a combined license (COL) or a construction permit (CP) that references this early site permit (ESP) shall perform detailed geologic mapping of excavations for safety-related engineered structures; examine and evaluate geologic features discovered in those excavations; and notify the Director of the Office of New Reactors, or the Directors designee, once excavations for safety-related structures are open for examination by NRC staff.
October 17, 2018 22
Staff's Conclusions for CRN ESP SSAR Section 2.5.3 Negligible potential exists for tectonic surface deformation that could adversely affect suitability of the CRN Site. Karst is the primary potential hazard for non-tectonic surface deformation at the CRN Site.
The applicant described information related to assessment of features that might have a potential for producing tectonic and non-tectonic surface deformation at the site in SSAR Section 2.5.3 in full compliance with regulatory requirements in 10 CFR 52.17(a)(1)(vi) and 10 CFR 100.23(d) and in accordance with guidance in RG 1.208.
October 17, 2018 23
Section 2.5.2 - Vibratory Ground Motion October 17, 2018 24
Key Review Topics of Interest for Section 2.5.2
- Treatment of Eastern Tennessee Seismic Zone
- Approach to developing site-response analysis
- Development of 2-D site response analysis October 17, 2018 25
Treatment of Eastern Tennessee Seismic Zone (ETSZ)
- ETSZ is region of elevated seismicity rates.
- Small magnitude earthquakes
- Occur within basement rocks below sedimentary section
- Included in NUREG-2115 within seismotectonic and Mmax source zones
- Sensitivity studies done during study to ensure that source zones adequately SSAR Figure 2.5.2-26 capture seismicity in ETSZ
- Recent geologic studies interpret potential for larger (M6.5) earthquakes October 17, 2018 26
Treatment of Eastern Tennessee Seismic Zone
- Applicant performed two sensitivity studies following SSHAC guidance for Level II study
- Evaluate Mmax
- Evaluate Magnitude-Frequency relations
- Mmax values in NUREG-2115 encompass proposed Mmax developed using new data
- Recurrence of large magnitude events in NUREG-2115 consistent with proposed values in new geologic studies SSAR Figure 2.5.2-26
- Staff concludes that NUREG-2115 adequately captures current understanding of seismic hazard in the Eastern Tennessee Seismic Zone October 17, 2018 27
Probabilistic Seismic Hazard Analysis (PSHA) Confirmatory Calculations Staff independently calculated seismic hazard curves at the Clinch River site.
Comparisons show that the seismic hazard curves are in good agreement at the annual frequency of exceedances of interest: 10-4, 10-5, and 10-6 October 17, 2018 28
Approach to Site Response Inputs
- Staff requested that applicant explain
- Clinch River site has how the use of multiple base cases accurately accounts for dip across site significantly dipping rock layers
- Approximately 30 degrees
- Applicant responded the smearing of
- High seismic velocities units is appropriate because mean and
- 5,000 to >10,000 fps range of values at a specific depth is maintained, implicitly accounting for
- Applicant developed site stratigraphic variations.
response inputs using
- 3 profiles for each location
- Staff performed confirmatory site
- Log mean seismic velocity as response considering dip explicitly (i.e.
upsection; middle; and downsection function of depth as base case profiles)
- Upper and lower case using log standard deviation
- Staff truncated profiles at the top of the
- Effect of smearing geologic units Knox Group due to thickness and together velocity of layer
- Staffs results are consistent with applicants October 17, 2018 29
Ground Motion Response Spectrum (GMRS) Confirmatory Analysis Staff developed alternative input parameters for site response analysis.
Staff independently calculated site response and developed a site ground motion response spectrum (GMRS) based on its preferred inputs. Site GMRS developed by staff is consistent with that developed by the applicant.
October 17, 2018 30
2-D Site Response
- Clinch River site has significantly dipping (>30 degrees) rock layers in subsurface
- RG 1.208 states that for sites with complicated subsurface structure, a multi-dimensional approach to site response may be necessary
- Applicant developed a 2-D site response analysis and compared amplification functions to 1-D results developed using 2-D inputs
- Staff requested that applicant compare 2-D results to 1-D results used in developing GMRS
- Applicants 2-D results compare favorably with 1-D results, satisfying staffs concern SSAR Figure 2.5.2-108 October 17, 2018 31
Staff Conclusions -
Section 2.5.2
- The applicant provided a thorough characterization of the seismic sources surrounding the site, as required by 10 CFR 100.23
- The applicant adequately addressed the uncertainties inherent in the characterization of these seismic sources through a PSHA, and its PSHA follows the guidance provided in RG 1.208
- Applicants GMRS adequately represents the regional and local seismic hazards and accurately includes the effects of the local site subsurface properties October 17, 2018 32
Section 2.5.4 - Stability of Subsurface Materials and Foundations 33
Summary of CRN ESP SSAR Section 2.5.4
- SSAR Section 2.5.4 presents the engineering properties of subsurface materials, and evaluation of stability of subsurface materials and foundations at the CRN Site.
- SER Section 2.5.4 includes:
The staffs evaluation of engineering properties of subsurface materials; foundation interfaces; geophysical surveys; excavation and backfill; groundwater conditions; response of soil and rock dynamic loading; liquefaction potential; stability of foundations 16 COL Action Items 1 Permit Condition 34
Plant Parameter Envelope
- In order to provide sufficient geotechnical information at the site without having a specific design, the applicant provided a surrogate design in its application. The surrogate plant approach covers a set of bounding parameters:
the plant parameter envelope (PPE).
- Under the PPE approach, the resulting ESP will be applicable for a range of reactor designs if their relevant design parameters fall into the PPE.
35
CRN ESP Site Exploration Boring Location Plan at the CRN Site (Reproduced from SSAR Figure 2.5.4.) 36
Site Stratigraphy Geotechnical Cross-Section of the Stratigraphy of the Power Block Area (Reproduced from SSAR Figure 2.5.4-1) 37
Key Review Topics of Interest for Section 2.5.4 Assessment of the Effects of Underground Voids on Foundation Stability
- Karst exists at the CRN Site and the underground voids may adversely affect the foundation stability.
- The applicants site investigation for the ESP application provided preliminary information on void distribution and size.
- The staff reviewed the applicants PLAXIS 2-D Finite Element (FE) model that assessed the effects of postulated underground voids on foundation stability at the CRN Site.
- The staff concludes that the applicant conducted an appropriate preliminary evaluation to determine potential karstic cavity impacts on the foundations.
- This analysis should be site location and technology specific, therefore the staff identified COL Action Item 2.5-2 which establishes that a future applicant referencing this ESP should reevaluate the potential of karstic cavity impacts, within the zone of influence of the foundation under all design loading conditions, on foundation stabilities for safety-related structures.
38
Key Review Topics of Interest for Section 2.5.4 Foundation Stability Analysis for CRN Site with Inclined Strata
- The CRN Site consists of multiple inclined layers of various rock formations with possible weakened interfaces between the formations.
- The staff reviewed the applicants multiple traditional methods and Finite Element (FE) methods used to assess foundation stability at the CRN Site.
- The staff concludes that the traditional methods results are in good agreement with those obtained from the finite element model and that the selected PPE values related to the site stability analyses are appropriate.
- The staff identified COL Action Items 2.5-12 through 2.5-14 for the COL or CP applicant to address the foundation stability of the site once a reactor technology and the specific location and extent of Seismic Category 1 structures is identified.
39
COL Action Items COL Action Items 2.5-1 through 2.5-16 pertain to reactor technology and site location specific actions that need to be addressed by the COL or CP applicant when referencing this ESP. Those COL Action Items are related to the following site characteristics:
- Site Geologic Features
- Properties of Subsurface materials
- Excavation and backfill
- Groundwater condition
- Static and dynamic stability
- Design criteria
- Techniques to Improve Subsurface Conditions 40
Permit Condition The site investigation data shows that the discontinuities, shear fractures zones, and weathered fracture zones typically exist within weathered rock in the uppermost 30.5 m (100 ft), where most of the cavities are encountered at the CRN Site. The rock mass characterization described in the application is mainly for bedrock stratigraphic units below 24.4 m (80 ft) (El. 225.9 m (741 ft) NAVD88),
the staff identified Permit Condition 2 in SER Section 2.5.4.5 as stated below:
An applicant for a combined license (COL) or a construction permit (CP) that references this early site permit shall remove the material above El.
225.9 m (741 ft) NAVD 88 in areas where safety-related structures will be located, to minimize the adverse effects of discontinuities, weathered and shear-fracture zones, and karst features on the stability of subsurface materials and foundations. The applicant shall also perform additional geotechnical investigations, in accordance with RG 1.132, at the excavation level to identify any potential geologic features that may adversely impact the stability of subsurface materials and foundations.
41
Staff Conclusions -
Section 2.5.4
- The applicant adequately determined the site-specific engineering properties of the subsurface materials underlying the CRN Site, and conducted sufficient evaluation of the stability of subsurface materials and foundations, based on the results of field and laboratory tests and the state of the art methodology, and in accordance with RG 1.132, RG 1.138, and RG 1.198.
- The staff concludes that the applicant meets the requirements of 10 CFR Part 52.17(a)(1)(vi) and 10 CFR Part 100.23(c) for this ESP application regarding the stability of subsurface materials and foundations.
42
Section 2.5.5 - Stability of Slopes 43
Section 2.5.5- Stability of Slopes
- The NRC staff reviewed SSAR Section 2.5.5, which provides general description of the site related to slope stability analysis.
- There are no existing slopes on the site at this time, either natural or manmade, that could affect the stability of the site.
- To address the need for future slope stability analyses, the staff identified COL Action Item 2.5-17 as stated below:
An applicant for a COL or CP application that references this early site permit should perform a slope stability analysis of any safety-related slopes, including dams and dikes, consistent with the selected reactor technology.
44
Staff Conclusions -
Section 2.5.5
- The applicant provided necessary information on site topography and geologic characteristics, and adequately described the slope characteristics at the site.
- The staff concludes that the SSAR Section 2.5.5 is adequate and acceptable because it meets applicable requirements of 10 CFR Part 50, Appendix S, 10 CFR Part 52.17(a)(1)(vi) and 10 CFR Part 100.23.
45