ML22095A008
| ML22095A008 | |
| Person / Time | |
|---|---|
| Issue date: | 03/18/2022 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| Howard, K., ACRS | |
| References | |
| NRC-1887 | |
| Download: ML22095A008 (164) | |
Text
Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION
Title:
Advisory Committee on Reactor Safeguards BWRX-300 Subcommittee Docket Number: (n/a)
Location: teleconference Date: Friday, March 18, 2022 Work Order No.: NRC-1887 Pages 1-106 NEAL R. GROSS AND CO., INC.
Court Reporters and Transcribers 1716 14th Street, N.W.
Washington, D.C. 20009 (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.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 www.nealrgross.com
1 1 UNITED STATES OF AMERICA 2 NUCLEAR REGULATORY COMMISSION 3 + + + + +
4 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 5 (ACRS) 6 + + + + +
7 BWRX-300, REVIEW TOPICAL REPORT NEDO-33914, 8 ADVANCED CIVIL CONSTRUCTION AND 9 DESIGN APPROACH LTR SUBCOMMITTEE 10 + + + + +
11 FRIDAY 12 MARCH 18, 2022 13 + + + + +
14 The Subcommittee met via Video 15 Teleconference, at 8:30 a.m. EDT, Jose March-Leuba, 16 Chairman, presiding.
17 COMMITTEE MEMBERS:
18 JOSE MARCH-LEUBA, Chair 19 RONALD G. BALLINGER, Member 20 VICKI BIER, Member 21 CHARLES H. BROWN, JR. Member 22 VESNA DIMITRIJEVIC, Member 23 GREG HALNON, Member 24 DAVID PETTI, Member 25 JOY L. REMPE, Member NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
2 1 ACRS CONSULTANT:
2 STEPHEN SCHULTZ 3
4 DESIGNATED FEDERAL OFFICIAL:
5 LAWRENCE BURKHART 6 HOWARD KENT 7
8 ALSO PRESENT:
9 OSSAMA ALI, GEH 10 DAVID CALHOUN, Black & Veatch 11 JOSEPH COLACCINO, NRR 12 JESUS DIAZ-QUIROZ, GEH 13 MICHAEL DUDEK, NRR 14 AMITAVA GHOSH, NRR 15 BRANDON GOMER, Black & Veatch 16 DAVID HINDS, GEH 17 TANYA KIRBY, GEH 18 AI-SHEN LIU, GEH 19 JUN MATSUMOTO, GEH 20 LISA SCHICHLEIN, GHH 21 ALINA SCHILLER, NRR 22 JAMES SHEA, NRR 23 ANGELO STUBBS, NRR 24 EDWARD STUTZCAGE, NRR 25 JORDAN SUPLER, GEH NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
3 1 LUBEN TODOROVSKI, GEH 2 JER-WEI MICHAEL TZANG, GEH 3 GEORGE WADKINS, GEH 4 WEI ZHENG, Black & Veatch 5
6 7
8 9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
4 1 C-O-N-T-E-N-T-S 2 PAGE 3 Opening Remarks . . . . . . . . . . . . . . . . . 7 4 Discussion of GE-Hitachi Topical Report, 5 "BWRX-300 Advanced Civil Construction and 6 Design Approach" . . . . . . . . . . . . . . . . 10 7 Staffs Evaluation of GE-Hitachis 8 Topical Report . . . . . . . . . . . . . . . . . 57 9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
5 1 P R O C E E D I N G S 2 (8:30 a.m.)
3 CHAIR MARCH-LEUBA: Okay, the meeting will 4 now come to order.
5 This is a meeting of the BWRX-300 and the 6 ACRS Subcommittee. I am Jose March-Leuba, the SC 7 Chairman.
8 Because of Covid-19 concern, this meeting 9 is being conducted in a hybrid manner. In addition to 10 the in-person attendance at NRC Headquarters, the 11 meeting is broadcasted via MS Team.
12 Members in attendance are Ron Ballinger, 13 Greg Halnon, Dave Petti, Joy Rempe, and myself. We 14 also have our consultant Steve Schultz.
15 MEMBER BIER: Jose?
16 CHAIR MARCH-LEUBA: And, Vicki Bier has 17 made it.
18 MEMBER BIER: Totally.
19 CHAIR MARCH-LEUBA: Today's topic is 20 topical report NEDC-33914P by General Electric-21 Hitachi, entitled BWRX-300, Advanced Civil 22 Construction and Design Approach.
23 All our meeting will be open to the 24 public.
25 We have not received request to provide NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
6 1 comments, but we have an opportunity for a spur of the 2 moment public comments before the end of the meeting.
3 The ACRS was established by a statute and 4 is governed by the Federal Advisory Committee Act, 5 FACA.
6 As such, the committee can only speak 7 through its published letter reports. The rules for 8 participation in all ACRS meetings were announced in 9 the Federal Register, on June 13, 2019.
10 The ACRS section of the U.S. NRC public 11 website, provides our charter, bylaws, agendas, letter 12 reports, and full transcripts for the open portions, 13 and all, of all full and subcommittee meetings, 14 including the slides presented there.
15 The designated federal official today is 16 Kent Howard.
17 A transcript of the meeting is being kept, 18 therefore, speak into the microphones clearly, and 19 state your name for the benefit of the court reporter.
20 Especially if you are joining the meeting using the 21 bridge line.
22 Please keep the microphone on mute when 23 not in use, and don't use videotape to minimize 24 bandwidth problems.
25 We are expecting to address this topic NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
7 1 during the full committee meeting on April 7, and 2 possibly write a letter.
3 At this point, I would like to request 4 Mike Dudek from NRC, to present his opening remarks.
5 Go ahead, Mike.
6 MR. DUDEK: Thank you, sir.
7 Good morning, Subcommittee Chairman March-8 Leuba, and the rest of the ACRS Subcommittee. Thank 9 you for your attention in this very important matter 10 today.
11 GE-Hitachi submitted this licensing 12 topical report to the staff in January of 2021, 13 entitled the Advanced Civil Construction and Design 14 Approach Methodology.
15 And, really at the end of the day, they 16 submitted this topical report as a, as to help their 17 design and analysis approach for construction during 18 future licensing activities.
19 But really, the purpose of the licensing 20 topical report is to provide guidelines for design 21 analysis, monitoring, and requirements for the 22 construction of their new, small modulate reactor 23 design, the BWRX-300.
24 This comprehensive approach and safe 25 operation was evaluated, design approach was evaluated NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
8 1 by the staff over the last eight to 10 months.
2 We diligently had several discussions, 3 public meetings, and RAI clarification calls with GE-4 H, that went very, very well.
5 This was a very good technical back and 6 forth with the NRC's technical staff, and their 7 counter-parts at GE-H. And, I think we developed a 8 very good product.
9 So, the staff is excited about presenting 10 this to you today, and we hope to hear your feedback, 11 and your insights.
12 So, without any further ado, I'll turn it 13 back over to you, Subcommittee Chairman March-Leuba.
14 CHAIR MARCH-LEUBA: Thank you, Mike.
15 And, we're going to transfer to General 16 Electric, who will make their first presentation. I 17 believe probably George Wadkins is going to give us 18 some introduction remarks.
19 GE, go ahead.
20 MR. WADKINS: Yes, thank you.
21 Good morning, my name is George Wadkins.
22 I am the Vice-President New Power Plants and Products 23 Licensing for GE-Hitachi.
24 I wish to thank the ACRS Subcommittee for 25 allowing us to present this overview of the BWX-300 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
9 1 Small Modular Reactor Design, with emphasis on the 2 description of the content for this licensing topical 3 report, NEDO-33914, BWX-300 Advanced Civil 4 Construction and Design Approach.
5 Today we will be providing an overview of 6 the layout of the BWRX-300 buildings, and describe the 7 design analyses, construction, inspection, and 8 monitoring approaches used for the BWX-300 deeply 9 embedded below-grade reactor building.
10 As noted in our previous discussions with 11 ACRS members, the BWX-300 builds upon our extensive 12 experience in boiling water reactor technology.
13 Including our most recent experiences in development 14 and certification, of the economic simplified boiling 15 water reactor, or ESBWR.
16 A major difference between the ESBWR and 17 the BWX-300 is in the use of a below-grade reactor 18 building, and in the innovative construction approach 19 to be used.
20 The ESBWR utilized a much larger nuclear 21 island, using tradition site excavation and 22 preparation methods, and traditional design for the 23 building foundations and structures.
24 The innovative design of the deeply 25 embedded below-grade reactor building, affords NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
10 1 significant cost savings and materials, and in 2 construction labor, and time, while providing a robust 3 structure for housing the safety related systems and 4 components of the BWRX-300.
5 I first want to thank the NRC staff for 6 their in-depth, professional review of this licensing 7 topical report.
8 The interactions with the NRC staff were 9 extremely useful in ensuring that the content of the 10 licensing topical report were complete, 11 understandable, accurate, and met the applicable 12 regulatory requirements and guidance.
13 I look forward to continuing this, and 14 future interactions, with the NRC staff and ACRS.
15 Next slide, please.
16 For this meeting, we are providing for an 17 extensive open session discussion of the content of 18 this licensing topical report, as shown in this 19 agenda.
20 This licensing topical report does not 21 contain any proprietary information.
22 During our presentation, we will pause at 23 the end of each slide to allow for questions from the 24 ACRS members, but please feel to raise questions at 25 any time.
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11 1 In the unlikely event that discussions do 2 involve proprietary information, then we will request 3 tabling that question until a closed session can be 4 established.
5 Next slide, please.
6 I will now turn over the presentation to 7 Lisa Schichlein, the U.S. Licensing Manager for the 8 BWX-300.
9 CHAIR MARCH-LEUBA: Lisa, let me interrupt 10 you for a moment. Two things first.
11 I referred to this topical report as an 12 NEDC in my opening remarks, and I note it is an NEDO.
13 It's just a, sorry, I mean, almost all reports we 14 review are always proprietary. And the NEDOs are not.
15 And I also wanted to mention that members 16 Vesna Dimitrijevic and Charlie Brown, have joined us.
17 Go ahead, GE.
18 MR. WADKINS: Thank you.
19 MS. SCHICHLEIN: Thank you.
20 Good morning, my name is Lisa Schichlein 21 as George mentioned, and I am the U.S. Licensing 22 Manager, for new power plants and products at GE-23 Hitachi Nuclear Energy Americas.
24 I would like to thank the ACR Subcommittee 25 for the opportunity to present the BWRX-300 Advanced NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
12 1 Civil Construction and Design Approach licensing 2 topical report.
3 With me on the call today are Licensing 4 Engineer Lamia Chouha, Ossama Ali, the Engineering 5 Manager for Civil and Balance of Plant Systems, Luben 6 Todorovski, Principal Engineer for Civil and 7 Structural, Tanya Kirby, a Senior Project Engineer.
8 Jordan Supler, a Senior Civil and 9 Structural Engineer, David Hinds, the Principal 10 Engineer for Plant Integration, and Jesus Diaz, the 11 U.S. Licensing Manager for the U.S., for the BWRX-300.
12 And, from Black & Veatch, we have Brandon 13 Gomer and Wei Zheng, Geologist and Geotech Engineer, 14 respectively.
15 We also have Engineering Manager Michael 16 Tzang, and Nuclear Chief Engineer David Calhoun. And 17 finally with us today, are Bernard Gilligan and Jun 18 Matsumoto, from Hitachi America, Ltd.
19 As questions arise, I may call upon one or 20 more of these people to address the question.
21 Before we begin, I understand it would be 22 helpful to show the ACRS Subcommittee, the BWRX-300 23 buildings discussed in the topical report, along with 24 their seismic classifications, and clarify the grade 25 level for the reactor building shaft.
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13 1 This figure illustrates the conceptual 2 site plot plan for a BWRX-300 single unit plant. The 3 control building, turbine building, and rad waste 4 building structures, are supported by a near-surface 5 base mat foundation, and are located adjacent to the 6 deeply embedded seismic category 1 reactor building 7 structure.
8 The control building, turbine building, 9 and rad waste building structures, are separated from 10 the reactor building by seismic gaps.
11 The rad waste building, which houses the 12 systems for management of radioactive gas, liquid, and 13 solid radiological waste, is categorized as an RW2A, 14 in accordance with Regulatory Guide 1.143.
15 The control building, which houses the 16 control room, electrical control and instrumentation 17 equipment, and the turbine building, which encloses 18 the turbine generator, main condensor, condensate and 19 feedwater systems, condensate purification system, 20 off-gas cooler and refrigerant dryer, turbine 21 generator support systems and the bridge crane, are 22 non-seismic.
23 CHAIR MARCH-LEUBA: So, let me, it's okay, 24 you can keep the slide. This is better.
25 The only seismic class 1 is the reactor NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
14 1 building, the one that contains the nuclear island?
2 MS. SCHICHLEIN: Correct.
3 CHAIR MARCH-LEUBA: And, everything else 4 interfaces to it? That you have to deal with?
5 MS. SCHICHLEIN: Correct.
6 CHAIR MARCH-LEUBA: Thank you.
7 MS. SCHICHLEIN: Moving on to slide 5, this 8 figure is a cut away of the plant, which illustrates 9 the ground level.
10 The reactor pressure vessel, the pressure 11 containment vessel, and other important safety related 12 systems and components, are located in the below-grade 13 reactor building, vertical right cylinder shaft, to 14 mitigate the effects of possible external events, 15 including aircraft impact, adverse weather, flooding, 16 fires and earthquakes.
17 MEMBER BROWN: Lisa, what is the, in the 18 seismic gas, what material is in there?
19 MS. SCHICHLEIN: I'm going to defer that 20 question, if possible, to Luben Todorovski, with 21 please unmute and address that question.
22 Thank you.
23 MR. TODOROVSKI: Yes, I think the better 24 one will be David Hinds to answer this.
25 MEMBER BROWN: Could you show where the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
15 1 seismic gaps are also?
2 MR. TODOROVSKI: Oh, the seismic gaps.
3 MEMBER BROWN: In between the buildings.
4 CHAIR MARCH-LEUBA: No, the --
5 (Simultaneous speaking.)
6 MEMBER BROWN: Okay, I got it.
7 CHAIR MARCH-LEUBA: The amounts that you 8 see is minor there, so.
9 MEMBER BROWN: Oh, okay. All right, I 10 figured that was it, I just needed to make sure I 11 knew.
12 Thank you.
13 MR. HINDS: Yes, there's no plans for 14 anything in the seismic gap, if that was the question.
15 There's of course, some coverage to keep 16 the weather out, and to maintain the materials. But 17 there's no plans for any equipment, or any materials 18 in that gap.
19 MEMBER HALNON: Okay, so how do you keep 20 water from coming up and down based on ground table 21 issues, and ground water issues, and rain and stuff?
22 I mean, you said a covering. I can 23 understand the outside, but is it open to just the 24 ground if the groundwater should come up?
25 MR. HINDS: Luben or others --
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16 1 (Simultaneous speaking.)
2 MR. TODOROVSKI: Yes, yes, it will be 3 protected from the roof so no water can enter inside.
4 And, there will be a gap. It will be the --
5 (Simultaneous speaking.)
6 MEMBER HALNON: Okay, so it's an open gap.
7 MR. HINDS: Between the structure, right.
8 MEMBER HALNON: There's no cork or any 9 other material in it?
10 MR. HINDS: No.
11 MEMBER HALNON: Okay. Thanks.
12 MS. SCHICHLEIN: Any further questions 13 before I move to the next slide?
14 (No audible response.)
15 MS. SCHICHLEIN: Let's now shift gears to 16 discuss the purpose and scope, for the topical report.
17 GE-H is seeking NRC approval for the 18 application of an alternative approach to the 19 construction, analyses and design, of the BWRX-300 20 below-grade reactor building.
21 To that end, the topical report presents 22 design analysis, and monitoring guidelines and 23 requirements, to support our request for approval for 24 an innovative and comprehensive construction approach, 25 for the construction of the below-grade BWRX-300 small NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
17 1 modular reactor, reactor building vertical right 2 cylinder shaft.
3 Over the next few slides I've listed some 4 of the criteria methodologies recommendations, and 5 approaches in the topical report. We will be covering 6 these in more detail in later slides.
7 Details --
8 (Simultaneous speaking.)
9 CHAIR MARCH-LEUBA: Lisa, let me interrupt 10 you at a high-level question that is dear to my heart 11 a little bit.
12 Topical reports are typically used to 13 define a methodology that later on, is referred by 14 reference in application.
15 So is this your intention that you will 16 have a final section license report, or license 17 request that will make a reference to this topical 18 report?
19 So this is not defining the design of the 20 BWRX-300?
21 MS. SCHICHLEIN: Correct.
22 CHAIR MARCH-LEUBA: It's only defining a 23 methodology that will be used in the future, to prove 24 that X-300 is correct?
25 MS. SCHICHLEIN: Yes, that is correct.
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18 1 CHAIR MARCH-LEUBA: Okay, thank you.
2 And, one more question. Would you be very 3 upset if I called your reactor an X-300? Because 4 BWRX-300 is kind of long.
5 (Laughter.)
6 MS. SCHICHLEIN: For the purposes of this 7 meeting, that is acceptable. That's fine. Thank you.
8 CHAIR MARCH-LEUBA: Okay, in writing we 9 always put the long name, okay? Thank you.
10 MS. SCHICHLEIN: The details on this 11 includes the following. The topical report presents 12 deterministic and probabilistic evaluation approaches, 13 to demonstrate that the one-step approach provides 14 conservative design demands, on the deeply embedded 15 reactor building structure.
16 To support the NRC staff review of the 17 one-step model, the topical report includes the 18 approaches used for developing the equivalent linear 19 static and dynamic, sub-grade properties that are used 20 as inputs to the one-step design analysis model.
21 The requirements and methodologies for 22 developing safe shutdown earthquake ground spectra, to 23 define the design ground motion along the depth of the 24 reactor building embedment, the additional 25 requirements for generating acceleration time NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
19 1 histories, as input the seismic soil-structure 2 interaction analyses.
3 The seismic soil-structure interaction 4 analysis approach, that provides then the bands for 5 the seismic design and qualification of structures, 6 systems and components, for all frequencies of 7 interest.
8 This information is included to 9 demonstrate that the approach adequately captures the 10 effects of structure soil-structure interaction, for 11 the deeply embedded reactor building with adjacent 12 structures and foundations.
13 It also includes different approaches that 14 can be taken, to demonstrate consistency between the 15 results from the deterministic soil-structure 16 interaction analyses of the reactor building 17 structure, with the results from the probabilistic 18 site response analyses.
19 It also includes approaches for performing 20 sensitivity evaluations from the effects of concrete 21 cracking, soil-structure interface conditions, soil 22 separation, and groundwater variations on the seismic 23 response, and design of the deeply embedded reactor 24 building structure.
25 It includes the comprehensive approach for NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
20 1 evaluating the effects of non-vertically propagating 2 seismic waves on the design ground motion, and seismic 3 response of the deeply embedded reactor building 4 structure.
5 Different approaches for considering 6 equipment structure interaction, to develop in-7 structure seismic response demands, for equipment 8 design and qualification.
9 Recommendations for performing non-linear 10 seismic soil-structure interaction analyses, for 11 sensitivity evaluations, and the graded approach for 12 the design of structures adjacent to the deeply 13 embedded reactor building, that include seismic 14 category 2/1 interactions.
15 As well as the method for developing 16 generic seismic, and geotechnical design parameters.
17 The scope of the topical report includes 18 the regulatory basis for this innovative approach, 19 guidelines for characterizing sub-surface conditions, 20 guidelines for performing the foundation interface 21 analysis, the design requirements, acceptance 22 criteria, and guidelines for the analysis and design 23 of the deeply embedded reactor building.
24 An approach for addressing seismic 25 category 2/1 interactions between the reactor NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
21 1 building, and the surrounding structures and 2 foundations, and the generic seismic and geotechnical 3 design parameters.
4 I'd now like to shift gears to discuss the 5 regulatory evaluation.
6 Before walking through the next few 7 slides, I want to state up front that the innovative 8 approach discussed in the topical report, meets the 9 intent of the current regulatory guidance for the 10 large light water reactors, and addresses the 11 specifics related to the seismic and structural 12 design, of deeply embedded small modular reactors.
13 I want to emphasize that GE-H is not 14 requesting NRC approval for exemptions from any 15 regulatory requirements, or exceptions to any 16 regulatory guidance.
17 The topical report complies with the 18 applicable Regulatory Guidance as written.
19 This slide, and the next few slides, 20 outline the regulatory basis specific to the 21 innovative approaches implemented for the analysis, 22 design, construction and maintenance, of the BWRX-300 23 important to safety structures.
24 So, on slide 12, the approach used for 25 defining and evaluating site sub-surface conditions, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
22 1 meets the regulatory requirements in 10 CFR 100, 2 100.20(c)(1), and 10 CFR 100.23, and the regulatory 3 guidance found in Standard Review Plan, Section 254, 4 entitled Stability of Sub-Surface Materials and 5 Foundations. As well as Regulatory Guides 1.132, and 6 1.138.
7 We have also considered IAEA safety guide 8 NS-G-6, in support of future license applications 9 outside of the United States.
10 The approach to use for defining and 11 evaluating site design parameters, meets the 12 regulatory requirements in 10 CFR 100.23(d)(1), and 13 the regulatory guidance found in Standard Review Plan 14 Section 3.7.1, entitled Seismic Design Parameters; 15 and, in Regulatory Guide 1.208, and Interim Staff 16 Guidance 17.
17 The seismic analysis meets the 18 requirements of 10 CFR 50, Appendix S, Earthquake 19 Engineering Criteria, with specific aspects of the 20 analysis meeting Standard Review Plan regulatory 21 guidance, and American Society of Civil Engineers, and 22 Structural Engineering Institute industry standards, 23 as noted on the slide.
24 The seismic analysis encompasses the soil-25 structure interaction analyses, fine element models, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
23 1 the effects of structure soil, structure interaction 2 of the reactor building, with surrounding foundations, 3 and the effects of non-vertically propagating seismic 4 waves, soil separation, concrete cracking, and soil 5 secondary nonlinearity on the seismic response and 6 design of the reactor building.
7 The approach used for evaluating the 8 seismic category 2/1 interaction, meets the guidance 9 of Standard Review Plan sections 332, entitled Tornado 10 Loadings; and, 372 entitled Seismic System Analysis, 11 as well as the industry standard ASCE SEI 43-05, 12 Seismic Design Criteria for Structures, Systems and 13 Components in Nuclear Facilities.
14 The approach used for performing the 15 testing, inspection and monitoring, meets the 16 regulatory requirements in 10 CFR 50, Appendix A, GDC 17 1, and 10 CFR 5065, and the regulatory guidance found 18 in Regulatory Guides 1.132, 1.136, 1.138, 1.142, and 19 1.160. As well as NUREG 5738, and NRC Inspection 20 Manuals88-131, 88-132, and 55-100.
21 CHAIR MARCH-LEUBA: Lisa?
22 MS. SCHICHLEIN: Yes?
23 CHAIR MARCH-LEUBA: Let me interrupt you 24 and make this presentation even more interesting. I 25 mean, you probably have been twice here as before. We NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
24 1 interrupt you all the time.
2 One concern we always have when we have 3 underground structures, is the coatings on the outside 4 of the concrete that you cannot inspect and test.
5 How do you handle 40/60/80 year lifetime 6 of a surface that you cannot inspect?
7 MS. SCHICHLEIN: That's a good question, 8 and I would like to defer that to some of my technical 9 colleagues. Luben Todorovski, or someone on your 10 team?
11 MR. TODOROVSKI: That particular aspect is 12 not powered by this topical report. We plan to issue 13 another topical report regarding that only in a 14 general sense, because it doesn't cover the, the 15 actual construction of the, of the reactor building.
16 We are working on that, and that will be 17 covered in a separate topical report.
18 CHAIR MARCH-LEUBA: So, we will hold our 19 breath and wait eagerly on that topical report.
20 (Laughter.)
21 MR. TODOROVSKI: Okay.
22 CHAIR MARCH-LEUBA: And, for what I have 23 read on the press releases, we should expect those 24 topical reports soon. So, we wait for it.
25 Thank you.
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25 1 MR. TODOROVSKI: Yes, thank you.
2 MS. SCHICHLEIN: Thank you.
3 New Mark 9301, industry guideline for 4 monitoring the effectiveness of maintenance at nuclear 5 power plants, is also used in the 10 CFR 5065 6 requirements.
7 I want to close out this section on the 8 regulatory evaluation, by restating that the design 9 and analyses described in the topical report, complies 10 with all applicable regulatory requirements and 11 guidance as written.
12 The approaches presented here meet the 13 intent of the current regulatory guidance for large 14 light water reactors, and address the specifics 15 related to the seismic, and structural design, of 16 deeply embedded small modular reactors.
17 GE-H is not requesting NRC approval for 18 exemptions from any regulatory requirements, or 19 exceptions to any regulatory guidance.
20 The methodology in this licensing topical 21 report ensures the safe operation of the BWRX-300 for 22 the life of the plant.
23 MEMBER HALNON: So, Lisa, if you're 24 complying with all the regulations and all the Reg 25 Guides, and all the guidance, what is innovative about NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
26 1 this?
2 CHAIR MARCH-LEUBA: Yes, let me rephrase 3 that.
4 MEMBER HALNON: Okay.
5 CHAIR MARCH-LEUBA: You refer to the 6 methodology as novel several times, even in writing.
7 For some of us that dump pool concrete into the ground 8 every other week, can you give us a layman's tutorial 9 on that?
10 MS. SCHICHLEIN: Actually, I would like to 11 defer that question as we go through the technical 12 evaluation, and that hopefully will answer some of 13 those questions.
14 CHAIR MARCH-LEUBA: Okay.
15 MS. SCHICHLEIN: But we will definitely 16 address that. But I'd like you to see our 17 presentation on the technical evaluation. Hopefully 18 that addresses that, that question.
19 Now let's shift gears and move into the 20 technical evaluation.
21 The topical report discusses the 22 innovative property characterization and monitoring 23 approach, which is driven by the reactor building 24 structure being deeply embedded.
25 There are several investigation, testing, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
27 1 and monitoring programs that will be used in 2 conjunction with the foundation interface analysis, 3 including a site investigation program, a sub-surface 4 material laboratory testing program, and construction 5 and in-surface monitoring programs.
6 Details of these programs were provided in 7 the topical report sections listed on the slide.
8 A three-dimensional foundation interface 9 analysis is performed to ensure the structure, and the 10 supporting media soil and rock, meet the stability 11 requirements of Standard Review Plan Section 2.5.4.
12 The analysis method includes interface 13 modeling, structural modeling, fuel, fluid-soil 14 interaction, and consideration of all plant life 15 stages.
16 The results of the foundation interface 17 modeling are used to evaluate construction plans, 18 including possible ground improvements, excavation 19 support, and foundation interface design.
20 The results are also used to verify the 21 reactor building shaft design.
22 CHAIR MARCH-LEUBA: Yes, and Lisa, I notice 23 on the SER there are some limitations and conditions 24 that impose, or at least remind the staff that during 25 the final review, they need to look at soil testing to NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
28 1 ensure that the stability is current.
2 Is that cover, I mean, are you comfortable 3 with those limitations?
4 MS. SCHICHLEIN: Yes. We had the 5 opportunity to review the limitations with the staff, 6 and found those limitations acceptable.
7 CHAIR MARCH-LEUBA: And, I find them very, 8 very useful that it will remind the staff when they 9 review the final design, what they need to do.
10 I mean, and they very logical to me. I 11 mean, make sure there are no big rocks close to the 12 containment that can fall on it if something slides.
13 MS. SCHICHLEIN: Certainly.
14 CHAIR MARCH-LEUBA: Yes. Thank you.
15 MS. SCHICHLEIN: Thank you.
16 On to slide 21. Various aspects of the 17 foundation interface analysis approach, go beyond 18 existing regulatory guidance of Standard Review Plan 19 2.5.4, entitled Stability of Sub-surface Materials and 20 Foundations.
21 Including the general modeling and 22 analysis requirements for stability evaluations, 23 guidelines for modeling the non-linear constitutive 24 response of soil and rock, and the approach for 25 calibrating the model based on data obtained from NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
29 1 field instrumentation, guidelines for modeling 2 interfaces, and structural modeling requirements.
3 The foundation interface analysis, excuse 4 me, I should have been back at slide 21 for this.
5 The foundation interface analysis modeling 6 approach, including guidelines for using the 7 measurements for field instrumentation, for model 8 calibration and bench marking results, also go beyond 9 existing guidance in SRP 385, entitled Foundations.
10 CHAIR MARCH-LEUBA: Yes, another question.
11 We have been following very closely, and 12 I'm sure you have, too, the issue with the alkali-13 silica reaction where the concrete expands over time.
14 And, obvious is additional stresses on 15 foundations, and especially a underground wall that 16 cannot expand easily.
17 Have you, and I'm sure you've thought 18 about this. How do we handle that in X-300?
19 MS. SCHICHLEIN: I'd like to defer this 20 question to David Calhoun, from Black & Veatch.
21 (No audible response.)
22 MS. SCHICHLEIN: David, if you could 23 unmute, please.
24 MR. CALHOUN: Good morning, this is David 25 Calhoun.
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30 1 CHAIR MARCH-LEUBA: Yes, we can hear you 2 now.
3 MR. CALHOUN: It's just a moment to get 4 everything wired up again.
5 So, we're very familiar with the ASR as a 6 topic for long-term maintenance, and the degradation 7 mechanism for concrete structures.
8 And, largely it goes to quality of 9 materials that are used in the initial construction.
10 The alkali-silica properties in aggregates that are 11 used for construction, that's essentially the control 12 feature that we have for initial construction.
13 CHAIR MARCH-LEUBA: I will be asking the 14 same question from the staff that there will be 15 obviously an inspection, or an audit, or something 16 like that, to ensure that the materials don't include 17 --
18 MR. CALHOUN: Right.
19 CHAIR MARCH-LEUBA: You always worry about 20 the next AS. I mean, obviously we know not to use 21 granite as an additive to concrete.
22 But which means what is going to be the 23 next ASR? You'll be looking for it.
24 MR. CALHOUN: Something similar to ASR but.
25 CHAIR MARCH-LEUBA: Yes.
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31 1 MR. CALHOUN: Unknown as yet.
2 CHAIR MARCH-LEUBA: Unknown, right.
3 MR. CALHOUN: So, just in terms of the, the 4 construction methods. Of course the reactor building 5 as safety related, is going to have the types of 6 aggregate and other cement and so forth, controls that 7 are typical for safety-related concrete.
8 So, just in that regard, nothing unusual 9 there. That's our standard industry approach.
10 CHAIR MARCH-LEUBA: Okay. So, let me 11 summarize.
12 You will have a good quality control on 13 your materials --
14 (Simultaneous speaking.)
15 MR. CALHOUN: Absolutely.
16 CHAIR MARCH-LEUBA: -- to prevent this --
17 MR. CALHOUN: Segregation, and you know, 18 other testing on those materials.
19 CHAIR MARCH-LEUBA: And, you know, one of 20 the mitigation items that have been implemented on ASR 21 plans, is to add some I'm going to call it nails, or 22 markers, so that theoretically, they have to do it 23 every month. You measure the expansion of concrete.
24 Have you considered using, it's equivalent 25 to those coupons that you put on the vessels to make NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
32 1 sure that the vessel is not degrading, from nuclear 2 fluids. Adding some markers on the wall of the RARB, 3 so that in five or 10 years, you can measure that it 4 has not been expanding?
5 MR. CALHOUN: Sure.
6 CHAIR MARCH-LEUBA: If you design it from 7 the design, it cost nothing and it might help you a 8 lot in the future to ensure the regulators it's not 9 expanding. We don't have any problems.
10 MR. CALHOUN: Very well, and as I think 11 Luben said, those will go, those will be developed 12 going further.
13 I think the initial approach is we want to 14 do everything that has been learned in the industry, 15 to avoid ASR.
16 MEMBER BALLINGER: Yes, the best procedure 17 is not to have it.
18 MR. CALHOUN: Right.
19 CHAIR MARCH-LEUBA: But if you install some 20 markers, or some nails, to measure the distance and 21 make sure it's not expanding during construction, 22 doesn't cost anything.
23 MEMBER BALLINGER: Except for the 24 inspection program.
25 MEMBER REMPE: When it's down there.
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33 1 MR. CALHOUN: Yes, I think Lisa mentioned 2 that so there --
3 (Simultaneous speaking.)
4 CHAIR MARCH-LEUBA: Just an idea of 5 somebody who doesn't know anything.
6 MR. CALHOUN: Yes, so 5065 is going to 7 apply, and effectiveness, maintenance, and those types 8 of examinations, those are expected.
9 CHAIR MARCH-LEUBA: Thank you. Lisa, you 10 can continue.
11 MEMBER BALLINGER: This is Ron Ballinger 12 again.
13 MS. SCHICHLEIN: I'm sorry, before we 14 proceed, we have another gentleman on our GE-Hitachi 15 team who'd like to comment on that.
16 MR. TODOROVSKI: Right, I just want to 17 mention that the oldest procedure will depend on the 18 actual design of the structure, which is not covered 19 in this LPR.
20 For example, we are intending to use 21 different type of structure than the reinforced 22 concrete structure.
23 And basically all these measures will be 24 either less important for the type of construction we 25 plan to do, or they are not applicable.
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34 1 CHAIR MARCH-LEUBA: Is that --
2 (Simultaneous speaking.)
3 MR. TODOROVSKI: So that's why, yes, we 4 don't have it in the LTR. This LTR we won't cover 5 that.
6 CHAIR MARCH-LEUBA: Right, is that type of 7 construction proprietary? Because I've heard of 8 something, and I don't know if it's proprietary or 9 not.
10 MR. TODOROVSKI: It's not, not to my 11 knowledge. But it will be steel concrete composite.
12 CHAIR MARCH-LEUBA: Okay, composite with 13 steel, right?
14 MR. TODOROVSKI: Right, which will have the 15 steel plates, and then the concrete inside the steel 16 plates.
17 CHAIR MARCH-LEUBA: Right, and that will, 18 you expect to lower the cost and, under the schedule 19 significantly by using the --
20 (Simultaneous speaking.)
21 MR. TODOROVSKI: Mostly schedule, yes, 22 mostly schedule.
23 MEMBER BALLINGER: And remember, there's we 24 looked at a Reg Guide. We looked at that concrete 25 composite.
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35 1 MALE: Uh huh.
2 MEMBER BALLINGER: These plants generally 3 have a very long life, and they keep getting extended, 4 hopefully in our case.
5 The rules with respect to concrete 6 construction differ depending on the perceived 7 importance of the structure, particularly in respect 8 to the cover thickness over concrete structure, over 9 the rebar.
10 Has there been thought to shall we say, 11 increasing the cover thickness on some of these 12 external structures, in anticipation that the life 13 might be a lot longer than 40 years?
14 MR. TODOROVSKI: Yes.
15 MEMBER BALLINGER: There's a, I think 16 there's a two-inch requirement on some structures; and 17 a three-inch on another; maybe a four-inch on some 18 others.
19 MR. TODOROVSKI: Yes, we are looking into 20 that but as I said, that will be a separate topical 21 report. Because at the time this topical report was 22 written, the design wasn't, I mean we were not sure 23 how to proceed.
24 MEMBER BALLINGER: Yes, I mean the ACIs, 25 they allow for certain minimum covers. But it doesn't NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
36 1 require you to stick to that.
2 MR. TODOROVSKI: Yes, and for the SC 3 construction, for example, there are different 4 requirements related to the effect of the water 5 rusting, and stuff like that.
6 But as I said, I will defer that for the 7 next topical report topic.
8 MS. SCHICHLEIN: Yes, we appreciate that 9 question, and I think it will be covered in more 10 detail in that future topical report.
11 MEMBER BALLINGER: And, now also, I also 12 assume that this future topical report will address 13 the issue of groundwater. In particular, chloride 14 composition, chloride content and other chemicals, 15 which might affect the underground concrete if it gets 16 accessed through the, through the coating?
17 MR. TODOROVSKI: It --
18 (Simultaneous speaking.)
19 MS. SCHICHLEIN: At this -- go ahead, 20 Luben, please.
21 MR. TODOROVSKI: Yes, that is the intent.
22 Basically, we want to cover a lot of aspects about the 23 new design of the structure. And, I don't know if 24 it's appropriate right now to discuss those topics, 25 but we are working on that.
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37 1 MR. ALI: So, the chloride content in the 2 groundwater as part of the corrosion mitigation 3 process, will be accounted for in the next LT.
4 MEMBER BALLINGER: Right, thank you.
5 MS. SCHICHLEIN: Thank you --
6 (Simultaneous speaking.)
7 CHAIR MARCH-LEUBA: Before, Lisa, before 8 you continue, court reporter, we are not giving our 9 names before because everybody as a follower can see 10 except you, is joining through MS Teams.
11 Do you want us to give you the names ahead 12 of our presentation every time we speak, or are you 13 happy with MS Teams?
14 (OFF RECORD COMMENTS.)
15 CHAIR MARCH-LEUBA: Continue, Lisa.
16 MS. SCHICHLEIN: Thank you. And, this is 17 Lisa Schichlein continuing again. We're on slide 22.
18 The topical report discusses the 19 innovative static and seismic structure interaction 20 analysis approaches, for designing the deeply embedded 21 reactor building structure.
22 And, details the requirements, 23 methodologies, and recommendations for developing site 24 specific geotechnical, and seismic design parameters 25 based on the results of site investigations, and NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
38 1 laboratory testing programs.
2 Requirements and recommendations presented 3 in the topical report, ensure that the seismic soil-4 structure interaction analyses, use input motion that 5 is adequate throughout the depth of the reactor 6 building embedment.
7 The topical report also outlines a 8 comprehensive recommended approach, for evaluating the 9 effects of non-vertically propagating seismic waves on 10 the design, ground motion, and seismic response of the 11 deeply embedded reactor building structure.
12 And, recommends approaches for developing 13 in-structure seismic response demands for equipment 14 design and qualification, considering 15 equipment/structure interaction.
16 The design analysis also introduces 17 additional requirements for generating multiple 18 acceleration time histories with refined time steps, 19 which ensure the mitigation of uncertainty in the 20 computed structural responses.
21 MEMBER BROWN: This is Charlie Brown. Can 22 I ask a question?
23 MS. SCHICHLEIN: Certainly.
24 MEMBER BROWN: I was noticing in the 25 technical, in the LTR, that you're talking about the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
39 1 stress and the, the stress demands and everything else 2 on the structure.
3 But you limited, I guess I've forgotten 4 what section it was in now, the depth you were 5 working, it was like 120 meters. And, for the 6 cylinder, the depth you can go to. And, then you've 7 got the base mat plane above that.
8 But how do you, is there any experience 9 anywhere with the cantilever loads, horizontal, 10 applied to the base mat when you have seismic 11 structures? I mean seismic waves that come through 12 different levels?
13 That's deep. That's football field length 14 plus 20 percent roughly. So, that's a huge cantilever 15 down there, and there's a lot of structure, soil-16 structure and layers, and everything else that are 17 different.
18 I'm not a civil engineer, but that seems 19 to be an obvious cantilever issue that. Is there any 20 experience anywhere that you can back that, or are you 21 all developing all this on your own for a first time?
22 MS. SCHICHLEIN: I'd like to direct that 23 question to Luben Todorovski.
24 MR. TODOROVSKI: Yes, first one correction.
25 The depth of the shaft is 120 feet, not meters. So NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
40 1 it's like three times less than what is mentioned.
2 But nevertheless, we are looking into it, 3 actually the focus of this LTR is to address those 4 issues, that we have a very deeply embedded structure.
5 And, the analysis we are doing is to take 6 the effect of the soil on the structure. And, 7 basically what is happening when you have a deeply 8 embedded structure, especially in soil materials, they 9 tend to drive the structure. And, the structure 10 deforms based on the deformation of the soil.
11 So we have, we are using methodology, 12 which is a proven methodology in the nuclear industry.
13 It's called the SSI for soil-structure interaction, 14 that takes all these effects into account.
15 Now, there are a lot of items, details 16 about how the structure behaves when you have such a 17 design where it is deeply embedded, that are different 18 than what we are used in the nuclear industry.
19 Those have been identified both by the 20 NRC. There is a NUREG/CR-7193, actually that captured 21 this effects for a small modular reactors that are 22 deeply embedded in soil.
23 And, we also identifying others, and the 24 focus of this report is to address those differences 25 in the analysis and design approach.
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41 1 MEMBER BROWN: I just don't remember seeing 2 one where I've got a large cylinder extending down 3 from the basement. Most, at least that's my memory.
4 It's been a fundamental overall building, has been 5 sub, you know, sub-surface.
6 But not a base plane and then, I'm right 7 now looking at the section that says for BWR purposes, 8 the engineering depth is set at 120 meters. 120 feet, 9 that's still pretty deep.
10 So, that's why I asked the question. It 11 just seems --
12 MR. TODOROVSKI: Right, and --
13 MEMBER BROWN: -- and hadn't seen it in 14 any other, any other designs we've looked at over the, 15 at least over the last 12 years that we've, that I've 16 been participating in. And, not being a civil 17 engineer.
18 MR. TODOROVSKI: Another clarification, if 19 Lisa maybe you can show the 3-D presentation of the 20 plant.
21 Basically the reactor building itself is 22 not connected to the basement on the surface. It's 23 separated from it. So --
24 (Simultaneous speaking.)
25 CHAIR MARCH-LEUBA: Slide 3 will be useful NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
42 1 here.
2 MR. TODOROVSKI: Right.
3 CHAIR MARCH-LEUBA: For discussion.
4 MS. SCHICHLEIN: Here, let me go, excuse 5 me, let me try to get back to slide 3 if I can. If I 6 can get back to that. One second, please.
7 MEMBER BROWN: No problem.
8 (Pause.)
9 MS. SCHICHLEIN: Do you --
10 (Simultaneous speaking.)
11 MR. TODOROVSKI: The other slide, actually.
12 Yes.
13 So, as you can see, this cylinder is 14 actually separated from the other buildings. So, 15 basically we have a deeply embedded cylinder inside 16 the, it's on the soils.
17 So, reactor building is supported by the 18 basement, which is deeply embedded down 120-feet below 19 the ground.
20 MEMBER BROWN: Okay, so that separation gap 21 is it in inches, or is it in feet?
22 MR. TODOROVSKI: It is approximately four 23 inches.
24 MEMBER BROWN: And, that's enough you 25 think, to handle the whatever horizontal loads that NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
43 1 you would be from any seismic disturbances that came 2 through in terms of the variation, the reactor 3 building from the other facilities?
4 MR. TODOROVSKI: Yes, we are considering 5 the interaction of this foundation and structures with 6 the, yes, and they are important. Quite important for 7 a design.
8 MEMBER BROWN: All right, thank you.
9 MR. TODOROVSKI: Thanks.
10 MEMBER HALNON: This is Greg. I got one 11 question back on the slide that you were on, on the 12 design, and I guess while you go back you can listen.
13 MS. SCHICHLEIN: Okay.
14 CHAIR MARCH-LEUBA: I think we were on 22.
15 MEMBER HALNON: 25.
16 CHAIR MARCH-LEUBA: 25?
17 MEMBER HALNON: Oh, I'm sorry, that's 25 on 18 the PDF. Twenty-two, slide 22.
19 The site investigations in order to make 20 this viable for people to look at to build. I mean, 21 clearly you want this thing, the methodology to be 22 able to bound all these different soil types, so that 23 you can show you can build it in many different 24 locations.
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44 1 investigations, beyond what's normally done for site 2 characterization because of the embedment?
3 MR. TODOROVSKI: Yes, correct. The 4 basically I think Section 3 of the LTR, we are 5 presenting methodology.
6 I mean, title is for the recommendations 7 for the site investigations, which go beyond the 8 current requirements for the large light water 9 reactors.
10 They are far more borings, or testings are 11 done to characterize the sub-grade materials, because 12 they are far more important for the stability of the 13 reactor building, than for a large building.
14 MEMBER HALNON: Did you guys talk about any 15 unintended consequences from that perspective? In 16 other words, finding, when you go deep like that, 17 you're going to find water tables are different than 18 what you thought, and I assume that this has to be 19 above the water table?
20 MR. TODOROVSKI: No, no. The water table 21 can be above the foundation, and then it is 22 waterproofing for that.
23 MEMBER HALNON: Okay.
24 MR. TODOROVSKI: But during the 25 construction, the buoyancy effects will be taken care NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
45 1 of.
2 MEMBER HALNON: Okay, so that goes back to 3 the earlier question that we'll get later on, on the 4 coatings?
5 MR. TODOROVSKI: Correct.
6 MEMBER HALNON: All right, thank you.
7 MS. SCHICHLEIN: On slide 23 now, a graded 8 approach is taken for the evaluation of seismic 9 category 2/1 interactions, between the seismic 10 category 1 reactor building, and the adjacent control 11 building, turbine building, and rad waste building.
12 The control building and turbine building 13 are non-seismic, and the evaluation also includes 14 determination of seismic and wind loads.
15 The rad waste building, which is category 16 RW2A, also includes determination of tornado wind, and 17 missile design loads.
18 CHAIR MARCH-LEUBA: Just have to (audio 19 interference) just because we know much about it. How 20 do you handle piping that goes to like a steam line, 21 that goes to containment?
22 MR. TODOROVSKI: You mean the, this is 23 Luben. Can you clarify when you say piping, do you 24 mean the piping going from the reactor building to the 25 turbine building, for instance?
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46 1 CHAIR MARCH-LEUBA: Correct. Say the 2 streamline for example.
3 MEMBER HALNON: This is Greg. Yes, the 4 rigidity of the lines going out --
5 (Simultaneous speaking.)
6 CHAIR MARCH-LEUBA: Yes, because if you 7 have the RB, the reactor building completely 8 unisolated from the turbine building, and have this 9 four-inch, I mean you have penetrations going from one 10 to the other.
11 MR. TODOROVSKI: Yes, that is correct. I 12 mean, we are calculating the relative displacement 13 with the building. Can we make sure those can be 14 accommodated by the design of the piping and other.
15 But this is nothing you, actually all the 16 designs, the turbine building is seismically isolated 17 from the reactor building. Not just for BWR and the 18 previous designs, but also for pressure reactors.
19 So, it is a standard procedure.
20 CHAIR MARCH-LEUBA: Thank you.
21 MS. SCHICHLEIN: The topical report also 22 includes the method for developing generic 23 seismological and geotechnical site parameters, using 24 generic design response spectra, sub-grade dynamic 25 properties, static properties, and the use of generic NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
47 1 values for friction coefficients.
2 In conclusion, I would like to wrap up 3 this presentation by restating that the design and 4 analyses described in the licensing topical report, 5 comply with all applicable regulatory requirements and 6 guidances written.
7 The innovative approaches discussed in the 8 topical report, meet the intent of the current 9 regulatory guidance for large light water reactors, 10 and addresses specifics related to the seismic and 11 structural design of deeply embedded small modular 12 reactors.
13 GE-H is not requesting NRC approval for 14 exemptions from any regulatory requirements, or 15 exceptions to any regulatory guidance.
16 The methodology in this licensing topical 17 report, will ensure safe operation of the BWRX for the 18 life of the plants.
19 CHAIR MARCH-LEUBA: So now that we go 20 through the whole presentation and without the 21 questions, can you give us a Reader's Digest version 22 of the novel features of this topical report? High-23 level for layman's.
24 MS. SCHICHLEIN: I'd like to defer that to 25 Luben. I think we've tried to walk through some of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
48 1 the high points, but if Luben and/or Brandon Gomer 2 would like, from Black & Veatch, would like to discuss 3 some of the details of the novel approaches, that 4 would be appreciated.
5 MR. TODOROVSKI: Okay, I will try my first, 6 and then maybe I can defer to Brandon as well.
7 For the high level, what this report is 8 doing is that we have a light water moving reactor, 9 which is not a new technology. What is different in 10 that is the way this design, the structure is 11 designed.
12 That is deeply embedded, which has some 13 safety features, safety benefits. But also it has 14 certain certainties into the design, which are new for 15 the industry.
16 For example, the effect of the surrounding 17 soil sampling conditions to the safety of this 18 reactor. We tried to address those new issues, and 19 ensure that the design is adequate and safe.
20 In the process, we have, we are in full 21 compliance with the regulatory guidance for the large 22 light water reactors. But we went beyond that in 23 order to address the specific issues of our design, 24 which is deeply embedded structure.
25 The newest thing about it is the whole NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
49 1 process we are following to meet this objective. So, 2 basically in that process, if I can share my screen, 3 is that going to be okay?
4 CHAIR MARCH-LEUBA: Lisa will have to stop 5 sharing hers, and then you will have to share yours.
6 MR. TODOROVSKI: Yes, I have one slide I 7 would like to show.
8 MS. SCHICHLEIN: Go ahead, Luben.
9 CHAIR MARCH-LEUBA: Yes, from the 10 administrative point of view, please send a copy of 11 this slide to our DFO, Kent --
12 MS. SCHICHLEIN: Yes.
13 CHAIR MARCH-LEUBA: -- because this is 14 part of the record now.
15 MR. TODOROVSKI: Okay.
16 MS. SCHICHLEIN: Yes, we will submit that 17 slide on the docket after the meeting.
18 CHAIR MARCH-LEUBA: Thank you.
19 MR. TODOROVSKI: And, basically, this is 20 Figure 1-1 in the LTR, but it's simplified; it's 21 easier to read.
22 And, basically this is the figure that 23 describes the process that goes to make sure that when 24 we come to the end of that, the reactor building 25 design, we are safe.
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50 1 So, as you can see, we have two processes 2 here, site investigation, and field and laboratory 3 tests.
4 Then we have monitoring programs, and the 5 in-service inspections also that go inside of this 6 process.
7 These three parts here are describing the 8 methodologies done, analysis done to develop the 9 inputs for our design, from which those symbols go to 10 the analysis, which are described in this yellow 11 boxes.
12 And, then basically those analysis that 13 provide the inputs for the design.
14 As a part of the design, we have a process 15 that goes, that has a sensitivity analysis, for 16 example, to address the known linear effects on the 17 seismic response.
18 And, also we have nonlinear foundation 19 interface analysis, that provide inputs that are used 20 to validate the design demands, and the design itself.
21 So, this is a unique process we have, that 22 we put all this different aspects of the design in 23 one. Not only to come to adequate inputs for the 24 design, but also to double-check, or to make sure the 25 design is safe.
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51 1 CHAIR MARCH-LEUBA: So, let me repeat what 2 I think I heard, and you tell me if I heard wrong.
3 You didn't really change that much the 4 process you have used for ESBWR, except that you were 5 forced to add some items because of being deeply 6 embedded underground, right?
7 You're site investigations, and soil are 8 more in-depth because the particular details of this 9 design require it.
10 And, in addition, you have added some 11 confirmatory boxes in this background, to ensure that 12 everything you're doing is, is working.
13 So, that, those are the two big 14 differences?
15 MR. TODOROVSKI: Yes, that is correct. In 16 addition to the site investigation program, we have a 17 maintenance which go much deeper for the design.
18 For example, we develop unique methods for 19 developing the input parameters for the design, which 20 is based on linear elastic assumption.
21 And, also we have nonlinear analysis to 22 validate those assumptions, which are usually you 23 know, adopted in the design. They are the basis for 24 all the designs we have so far.
25 So, that is correct. That basically we NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
52 1 are following what we are using for ESBWR, but with a 2 lot of other features that raise the specifics of the 3 deeply embedded structure.
4 CHAIR MARCH-LEUBA: Okay, thank you very 5 much.
6 MEMBER BALLINGER: This is Ron Ballinger.
7 And, when I read through this, I for the life of me, 8 couldn't figure out what was unusual except now that 9 you've explained the way you've put things together.
10 But what I was looking for was an 11 identification of the hard point. What is the most 12 difficult part of this? And, is it unique to the 13 embedded structure design?
14 MR. TODOROVSKI: We have spent a lot of 15 time together with the NRC staff working on the rock 16 properties.
17 In my personal opinion, I think here there 18 is something that is quite, goes far beyond that what 19 we are doing for the large nuclear power plants, which 20 are less of capable of the let's say, the rock masses 21 abilities.
22 So, that is one of the things we went much 23 further than whatever is done right now for the, or 24 has been done for the design of large nuclear power 25 plants.
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53 1 MEMBER BALLINGER: Okay, so it's just more 2 extensive analysis. But what I guess what I'm asking 3 is, where is, is there a fence here that results in 4 risk?
5 MR. TODOROVSKI: Inherently, going below 6 ground for example, for seismic, it's actually safer.
7 There are very few structures, underground structures, 8 that experience damage during earthquakes unlike 9 structures found on the surface.
10 But there are issues with for example, 11 with the rock stability, and the effects of how the, 12 the soil properties will affect the response of the 13 structure. Because when you are deeply embedded, the 14 soil has far more importance.
15 The in-situ soil mass has far more 16 importance on the design and the, and the response of 17 the structure than for a large building, which is.
18 And, basically that the only in the 19 construction process is such, which minimizes the 20 backfill for example. And, minimizes the excavation.
21 So, for a large plant, we will remove a 22 large quantity of soil, so the soil surrounding the 23 large plant will be basically engineered backfilled.
24 In this case, we minimize the excavation 25 so the in-situ soils as they are, we have far larger NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
54 1 effect on the design of the reactor building, than for 2 the large nuclear power plants.
3 And, that there are aspects on that we are 4 trying, aspects and uncertainties related to it, that 5 we have developed approaches to address.
6 MEMBER BALLINGER: Now, can you mitigate a 7 lot of any issues by using a backfill? In other 8 words, could you basically put this structure in what 9 amounts to a constant environment by using backfill?
10 MR. TODOROVSKI: That is not necessary, and 11 it doesn't mean that the basically, we will achieve 12 that unless there is a really adverse in-situ site 13 conditions, which maybe will result in the site not 14 being corrected for that.
15 And, actually, will increase the cost of 16 the construction to, not to be, it's better to have 17 large power plant.
18 MEMBER BALLINGER: Yes, you might end up 19 having to think about that, if you have a site which 20 is near a coast, and where you have a, it's a brackish 21 water site.
22 MR. TODOROVSKI: Correct. And, basically 23 our intention in the generic design, as it is written 24 in Section 7, is to make this design applicable for 25 variety of, a majority of candidate sites, which are NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
55 1 fit-able for building large industrial structures, and 2 especially nuclear structures, to cover 80 percent of 3 them.
4 But there certainly will be the site 5 conditions which won't be economically viable for 6 applying this design.
7 MEMBER BALLINGER: Thank you.
8 MR. TODOROVSKI: Thank you.
9 CHAIR MARCH-LEUBA: Members, any more 10 questions for GE?
11 (No audible response.)
12 CHAIR MARCH-LEUBA: Hearing none, we're 13 going to transfer to the staff, but first we are 14 scheduled for a 15-minute break. Let me get access to 15 the clock.
16 On our official clock if I can see it, no 17 that one is not the official one. Okay, 9:32. Let's 18 come back at 9:50. That gives time for the staff to 19 prepare for their presentation.
20 We are 15 minutes ahead of schedule so 21 we're doing fine.
22 So, we are in recess until 9:50.
23 (Whereupon, the above-entitled matter went 24 off the record at 9:32 a.m. and resumed at 9:50 a.m.)
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56 1 in session. The staff is going to present their 2 evaluation of this topical report.
3 Go ahead.
4 MS. SCHILLER: Good morning. Everybody 5 should see my screen. My name is --
6 CHAIR MARCH-LEUBA: We are seeing it.
7 MS. SCHILLER: Okay. Thanks.
8 My Name is Alina Schiller. I am a Project 9 Manager in the NRC Office of Nuclear Reactor 10 Regulation, Division of New and Renewed Licenses, New 11 Reactor Licensing Branch.
12 I would like to thank the ACRS 13 Subcommittee, GE-Hitachi, Nuclear Americas, and the 14 general public for entertaining the NRC for the 15 presentation of the staff safety evaluation of GEH 16 BWRX-300 Advanced Civil Construction and Design 17 Approach Licensing Topical Report.
18 In January 2021, GEH submitted Revision 0 19 of this licensing topical report to NRC. After 20 acceptance of the topical report in March 2021, the 21 NRC issued two requests for additional information, 22 REIs, to GEH in July of the same year. GEH provided 23 answers to the NRC's REIs in August, September, and 24 November of the last year. GEH issued Revision 1 of 25 its topical report to the NRC November of 2021. We NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
57 1 are here today to discuss the staff's advanced safety 2 evaluation of the topical report.
3 The NRC staff reviewers are Dr. Amitava 4 Ghosh, who is the lead technical reviewer and 5 presenter; Dr. David Heeszel; Edward Stutzcage; Angelo 6 Stubbs; and Sujit Samaddar. I am the topical report 7 Project Manager, supported by Senior Project Manager 8 James Shea.
9 Before I introduce Dr. Ghosh, I would like 10 to open the floor to NRC management: Joseph Colaccino, 11 Branch Chief of the Structural, Civil, and 12 Geotechnical Engineering Branch.
13 MR. CHOLACCINO: Alina, thank you very 14 much, and good morning.
15 First, I'd like to address some of the 16 questions that came up in the GEH presentation.
17 Again, my name is Joe Colaccino. I am the Chief of 18 the Structural, Civil, and Geotechnical Engineering 19 Branch.
20 We regarded this as a unique topical 21 report, and I resonated with one of the member's 22 questions: what's really novel about this report? And 23 to be quite honest, we asked ourselves that question 24 after our first read. And to the credit of GEH, they 25 worked with us in a number of public interactions to NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
58 1 describe to us the areas that they wanted us to look 2 at in their topical report. It's quite extensive.
3 The way we decided to proceed on the 4 development of our safety evaluation is to go through 5 the topical report and systematically provide findings 6 on each one of the items there. It's fairly 7 comprehensive what we did, but quite honestly, some of 8 those things, where basically -- yeah, what you're 9 looking at looks reasonable.
10 So what we focused on, what we are about 11 to focus on in this presentation, is the limitations 12 and conditions. And Dr. Ghosh is going to give you 13 that with some background that will help him describe 14 what his process was in going through this.
15 The other thing is I heard some discussion 16 here of the alkali-silica reaction, ASR, and I heard 17 that the staff would be asked that question. So I'd 18 like to preempt that question with where we stand 19 right now. We did not have that as a consideration in 20 the review of this topical report. We do not have the 21 experts here today, which do reside in the Structural, 22 Civil, and Geotechnical Engineering Branch, that are 23 dealing with ASR issues.
24 My understanding is that ACRS has a 25 meeting on this next month. And we will be there, and NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
59 1 we will support that meeting.
2 So, with that, I'd like to turn over the 3 presentation to Amit. Thank you very much.
4 MR. GHOSH: Good morning, everybody. Can 5 everybody hear me?
6 CHAIR MARCH-LEUBA: Yes, loud and clear.
7 MR. GHOSH: Thank you. I am Amit Ghosh.
8 I am a geotechnical engineer at the Structural 9 Engineering Branch. Before joining NFC, I used to 10 work for the Center For Nuclear Waste Regulatory 11 Analysis of the Southwest Research Institute. We were 12 an FFRBC of the NRC for the Yucca Mountain Project.
13 I worked on the Yucca Mountain Project for 14 20 years. We did a lot of laboratory experiments, 15 field experiments, small-scale experiments for NRC to 16 understand how an excavation in a jointed, fractured 17 rock must behave, especially during an earthquake.
18 When I was a graduate student, my emphasis 19 on my studies were on the rock excavations. And as a 20 teaching assistant, I used to take the students to the 21 field to do a lot of those field experiments, which 22 we'll be talking in very shortly in the presentation, 23 and do the field measurement, come up with those 24 parameters and classification system which we'll be 25 talking.
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60 1 With that background, I also have a very 2 good group of experts in their own areas, and we 3 together reviewed this LTR and developed a SE. So, on 4 their behalf, I will be presenting it today.
5 Next slide -- oh. I guess the next slide 6 is there.
7 So, first, I will give the big difference 8 what we saw with the traditional light-water reactor 9 and the BWRX-300 -- what is the main differences --
10 talk about the regulatory vessels we used to do the 11 review.
12 We reviewed the entire LTR, and there are 13 many areas where GEH has proposed the methodology.
14 And it will be too much to go through each of them, so 15 we listed or will be concentrating on the important 16 ones which we thought are important, and we'll present 17 those and how -- and one of the reason is most of them 18 has a little limitation and condition at the end.
19 There are other topics we reviewed. I 20 listed some of them but will not be discussing in this 21 presentation today. Then I'll talk about our review 22 strategy, how we approach to review this LTR, because 23 as Joe said and others said, this is a very unique LTR 24 where they give the methodology at the high level, but 25 there is no data or site information because this is NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
61 1 non-site specific.
2 And so I'll be discussing these five areas 3 in my presentation, and then at the end, I'll 4 conclude.
5 Next slide, please.
6 This is what in my opening is the 7 difference between a traditional light-water reactor 8 and this BWRX. The BWRX will be deeply embedded with 9 120 feet today in the vertical shaft. Most of the 10 other traditional light-water reactors are on the 11 surface. We may do an excavation, get to the rock, 12 and place the foundation over it, but not in the 13 shaft.
14 CHAIR MARCH-LEUBA: Let me -- I just 15 wanted to say that this picture is really interesting 16 of what happens underground when you build a reactor 17 in something like this. And this one is very obvious 18 because you can see it, but most of the time, you 19 cannot. So I would be interested to know within our 20 limitation and conditions how you detect something 21 like this that maybe is 50 feet underground.
22 MR. GHOSH: Yes. I will try my best.
23 Thank you.
24 We had one of the -- I mean, some of the 25 advantages of having it deep underground is to avoid NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
62 1 or minimize the effects of external hazards like 2 aircraft crashes, fire, flooding, tornado, tornado 3 missile. But it also poses some unique issues, like 4 it may be in the soil, deep soil site, or it may be in 5 the rock, where the soil is much less or the soil has 6 been excavated before construction of the shaft, or it 7 may have both.
8 And rock, as we just heard -- this is a 9 picture of a rock surface exposed, which is -- we can 10 see on the surface the rocks are fractured, so you can 11 see all these different types of fractures which are 12 present, which -- naturally, rock are fractured. It 13 has got joints. It may have bedding planes like the 14 different types of rock deposited at different 15 geological time in the history. So we have this 16 interface between the two.
17 We may have faults, like San Andreas Fault 18 -- not at that scale of hundreds of miles, but maybe 19 several hundreds of feet -- at the site. It may have 20 cast features, like cavities, if it is a Cal state 21 region. And all of these fractures, they do form a 22 network of -- fracture network, as you can see it 23 here. And I'll discuss this much detail later on.
24 Then we'll have the in-situ stress field 25 because we are deep there, 120 feet. So anything NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
63 1 above the 120 feet, all the material is giving the 2 load, which transform into the vertical load.
3 There will be horizontal load too. And 4 measurement at different sites shows that the tectonic 5 stressors, the plate tectonics, can influence that, 6 the horizontal stressors, at a given site.
7 And then we heard about the issues of 8 water table. Water table can be -- it may be totally 9 saturated because the clear water table is very close 10 to the surface, or it may be dry; the water table is 11 way below or in between somewhere.
12 And then another issue is how the rock 13 mass with the fracture -- I mean -- sorry, with the 14 vertical shaft with the reactor reacts to the 15 earthquake. And we have to understand the response 16 under the Safe Shutdown Earthquake, SSC.
17 Next slide, please.
18 GEH showed a much better picture, but this 19 was the picture in their LTR, so I am showing it.
20 Only a small part of the reactor will be above ground, 21 and rest is below ground 120 feet. There will be 22 three other structures nearby with the seismic gap.
23 Next slide, please.
24 So we used these regulatory vessels to 25 conduct the review. For subsurface condition, we use NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
64 1 10 CFR 100.20(c)(1). The Commission considers 2 physical characteristics of the site. 10 CFR 100.23 3 sets forth the principal geologic and seismic 4 considerations that guide the Commission in its 5 evaluation so that there is reasonable assurance that 6 a nuclear power plant can be constructed and operated 7 at the proposed site without undue risk to the health 8 and safety of the public.
9 For development of the site design 10 parameters, 10 CFR Part 50, Appendix A, General Design 11 Criteria, Criterion 2: design vessels for protection 12 against natural phenomena; and 10 CFR 100.23(d)(1),
13 requirements for defining the Safe Shutdown 14 Earthquake, SSC.
15 Next slide, please.
16 So I'll be going through these six topics 17 or approaches in this presentation as I discuss today, 18 and there are quite a bit of things which I'll not be 19 addressing through this presentation.
20 Next slide, please.
21 This is a list of other topics, plus there 22 are some more. There is design artificial load, how 23 they get the pressure on the reactor building, and 24 including the probabilistic artificial analysis, I 25 will be touching a little bit why probabilistic NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
65 1 analysis may be a better option than the deterministic 2 because a lot of uncertainties involved in determining 3 that pressure.
4 Development of groundwater and 5 acceleration time histories, the nonparticle 6 propagating seismic waves, approaches for meeting the 7 Interim Staff Guidance 017, modeling structure, soil 8 structure, interaction effect. You saw a very nice 3D 9 picture where we have this -- three other structures 10 close by about five inches apart with the seismic gap.
11 So when there is an earthquake SSC 12 happening, those structures are also responding to it.
13 And some part of the ground motion may be transferred 14 back and impact how the reactor shaft is responding to 15 it. So there will be some analysis on that. I'll not 16 discuss on that more.
17 Soil separation effect, it is a separation 18 of the reactor building from the surrounding medium, 19 which is a nonlinear effect. I'll not talk about 20 that, but we'll discuss how they propose to address 21 those nonlinear effects.
22 Groundwater radiation -- the GEH has 23 proposed to do a bonding analysis from completely dry 24 to completely saturated conditions and to bond the 25 effects of the groundwater and see whether the effects NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
66 1 needs to be considered in the design. And we also 2 heard about 201 (phonetic) interaction. So I will not 3 go into it any more.
4 Next slide, please.
5 Before we started to review this unit LTR, 6 we thought how to approach that, and we thought this 7 might be the best way to approach our review is 8 whenever they have given this -- they propose 9 different approaches for different technical issues.
10 And we thought first we should see whether the 11 approach is appropriate.
12 If it is appropriate, has this been used 13 other places, especially other nuclear applications --
14 if not, in other industries, in mining, constructions?
15 Because that gives the confidence that this method 16 works with similar areas. There may be different 17 tolerance in a nuclear application versus a mining, 18 but at least we know the method works, and then we can 19 work on the tolerance part.
20 Has the proposed has any limitations or 21 inherent assumptions which sort of restricts it to an 22 only small set of the parameters that can be used?
23 And whether there is a discussion that all the 24 parameter values will be appropriately determined in 25 site-specific applications so that we can complete the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
67 1 loop.
2 Next slide, please.
3 I'm showing the same picture again. The 4 rock, as everybody knows, is generally much harder 5 than the soil. But it has got these fractures. The 6 fractures is -- in this figure, you can see there was 7 a set of fractures which are dipping to the right, 8 about 45-, 50-degree angle.
9 And just as Alina is showing those set of 10 fractures, then there is another set which is dipping 11 sort of towards left, almost close to vertical, 80 to 12 85 degrees. And there is one set of fractures which 13 -- very faint, which is horizontal.
14 So these three fracture sets is forming 15 the isolated blocks in the rock mass. Each fracture 16 set has a dependent, how much it is dipping from the 17 horizon -- and then which direction it is dipping, 18 generally measured from the north. And each has a 19 spacing between the two fractures in the same set.
20 And as you can see in this illustrative 21 figure, there is a stochastic parameters. The numbers 22 are not constant. There is an average or mean value, 23 and there is a distribution around it, which will be 24 very useful to defining probabilistically how the load 25 will be coming onto the structure.
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68 1 So we, in a site-specific application, 2 will review how this rock fracture network has been 3 characterized. But we did not put in a limitation and 4 conditions because this is -- typically, these 5 fractures are mapped in any excavation, in a mining 6 construction or a nuclear project, installations for 7 the basement foundation.
8 So we did not think we need to put any 9 lancing on that. But GEH has proposed a modeling 10 technique to how each of these fracture behaves or 11 interface behaves.
12 Next slide, please.
13 This is a geological model given in the 14 LTR, Figure 4-2, to represent and tally the response 15 of any interface: rock versus rock, like joint bedding 16 planes, rock versus soil if we have two types of 17 materials, or rock versus a reactor structure, or soil 18 versus reactor structure.
19 So it is -- any interface can be 20 represented by this model if we have the correct 21 parameters. The parameters needed for this model to 22 be -- are given in the bottom block, normal stress, 23 normal stiffness, shear stiffness. If we look in the 24 first picture, that's how the -- it represents how the 25 interface will behave normally in the (audio NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
69 1 interference) across the interface. Second picture 2 gives how the interface will behave in -- along the 3 interface in the shear direction. And the third 4 picture gives how the interface will behave during 5 shear along the interface.
6 The normal strength is generally taking 7 the strength across the interface, generally taken as 8 zero. That means all are open. This type of -- I 9 have significant experience in using this model in the 10 Yucca Mountain Project, and we used that extensively 11 in our small -- experiments in the lab, direct test, 12 small-scale or a model scale structure in a rock mass, 13 and also worked the same model or same geological 14 model for analyzing rock bursts on a real mining 15 excavation in a zinc mine, very deep underground mine 16 in Idaho.
17 And this model works if properties are 18 given appropriately. And generally, an excavation in 19 a modeling will start with the pre-excavation stage.
20 That means nothing has -- we start from the zero. We 21 develop the stress field in that model. And then we 22 take off some of the blocks to simulate the excavation 23 and see how the stresses reorients itself, whether 24 displacements are taking place, and whether any of 25 these fractures slipping in that.
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70 1 And then GEH has proposed to have this 2 field instrumentation to measure those, so we can 3 correlate -- they can correlate very well with that 4 actual observation with the prediction. And you find 5 the modeling parameters as needed so that in the next 6 stage, they can predict what may happen before it 7 happens and then correlate again, and progress till 8 the start-up and operation.
9 So this is a very useful way of doing it.
10 It is generally done in an important project.
11 MEMBER HALNON: Amit, this is Greg. And 12 I'm not an expert in this area, so indulge just for a 13 second. When you're applying these models and 14 calculations and simulations pre-excavation, through 15 start-up and operation, is there anything that's 16 invalidated that you have to go back and look at again 17 if you have a small earthquake in the area that could 18 have at least some shaking and could be detected on-19 site?
20 I mean, I'm thinking of the North Anna 21 Earthquake where they had to do a lot of reanalysis of 22 plant systems. But is there anything here that would 23 require a reanalysis prior to a start-up from a small 24 earthquake that parameters could change enough to have 25 to look at it?
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71 1 MR. GHOSH: This model, what you see --
2 those three pictures, those are for an interface, like 3 a joint -- Alina, can we go back to the previous 4 slide, please?
5 It represents how any of these fractures 6 would behave given a load. The load could be static 7 or quasi-static or earthquake. In my previous job, we 8 did this study using an earthquake, and I'll be able 9 to show one of those pictures, how we tried to 10 simulate the effects of the earthquake.
11 But the North Anna is quite different 12 because there is no -- I don't know whether there is 13 or not underground excavation. I am not knowledgeable 14 about North Anna.
15 MEMBER HALNON: Well, there's some below 16 grade, but the reactor buildings typically do go a 17 little bit below grade. Yeah. But I was just 18 curious, in this, since it's so far below grade, if an 19 earthquake of a certain magnitude could affect the 20 point where we'd have to look at all these analyses 21 again to make sure that the joints are still where you 22 expect them, and the gaps and sliding frictions and 23 all those other stiffness parameters are the same. Or 24 could they change any significant amount based on 25 movement of the earth?
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72 1 MR. GHOSH: We used this model for the 2 zinc mine, zinc and silver mine in the -- I don't know 3 how to pronounce it, Couer d'Alene District of Idaho, 4 where you have rock bursts, which are mini-5 earthquakes. If you use the earthquake scale, it is 6 somewhere -- 2.23. Magnitude 2.23 earthquake, very 7 close by.
8 We monitor this every day. 24/7 we used 9 to monitor, and then we simulate that in our model, 10 whether we can see this very similar thing. And we 11 could see where the fractures -- I mean rock has 12 slipped and dislodged from the mine excavation, and we 13 could simulate that.
14 So this fracture model works. Given we 15 have appropriate properties, the model works. And 16 this model has been used, I can tell you, for many, 17 many projects around the world, like --
18 MEMBER HALNON: Okay. So it could be used 19 again to verify post-event that the plant would still 20 be safe to start up.
21 MR. GHOSH: Yes. Yes, sir, because the 22 model has been working mass mining in Australia, South 23 Africa where there is a lot of rock burst problem, in 24 excavation cuts and where we have the highway passing 25 through the hilly areas. This model works. This NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
73 1 model gives us -- fundamentally, this is how a rock 2 joint will behave given --
3 (Simultaneous speaking.)
4 MEMBER HALNON: Would that be a 5 consideration for a condition in their tech specs that 6 said post-earthquake, they would have to go back and 7 do some kind of reanalysis of the earth movement 8 around their plant to make sure the parameters are 9 within --
10 MR. GHOSH: Yes. So they already said 11 that they have this -- in this highly specific 12 application, they will be having this instrumentation 13 to measure those displacements. And they will be 14 correlating with the simulated results. And if 15 anything needed, the parameter values may need to be 16 tweaked.
17 Maybe the -- what the parameter values 18 request some adjustment. So they are going to do that 19 and use that in the next stages of development. So 20 you sort of callibrate your model when you start 21 simulating the fast excavations.
22 MEMBER HALNON: Thank you, Amit.
23 MR. GHOSH: Thank you, sir.
24 Next slide, please.
25 And this is one of the direct shear tests, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
74 1 how you get these model parameters. This, you 2 generally do it in a laboratory. You collect the 3 natural rock joint samples during site investigation 4 stage at the site.
5 And so this is one rock surface that will 6 be a complementary rock surface, so wherever you see 7 the red, which are the high peaks or white, and blue 8 is the troughs. So you'll be having just a middle 9 image of that.
10 So in the laboratory, on that emission, 11 you put both the samples together and make them so 12 that they are in the original position. And then you 13 try to push the top rock, keeping the bottom rock 14 steady in the same position. So it is like we are 15 doing a shear displacement, like how the San Andreas 16 Fault moves.
17 Next slide, please.
18 And this is the experiments. We did it 19 with (audio interference) Apache lift-off near 20 Phoenix, Arizona. So this is shear displacement 21 versus shear -- sorry, shear stress versus shear 22 displacement, and normal stress was just normal 23 displacement. So first figure is along the joint how 24 the strength varies.
25 Initially, these asperities are all NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
75 1 metered. So they are locked. You start moving within 2 a millimeter. It is elastic displacement. At this 3 point, you start first getting the asperity breakage 4 and the stress dropped.
5 You can see all these wiggly things where 6 it moves, gets locked with the different asperities, 7 and breaks, and then you see that that's what happens 8 in -- very close to the same phenomena in an 9 earthquake.
10 So, from the peak, as it goes, it is also 11 wrapped along the other asperities to make them kind 12 of smoother. If we do these experiments for a long 13 time, it will come to, really, two plane surfaces.
14 And that's the residual values.
15 This is the normal displacement plus the 16 shear displacement. So when the asperities are riding 17 over, so they're trying to go up, open up the joint.
18 So you started seeing these asperities.
19 In this experiment, the problem was moved 20 over 37 millimeters to the right. And then we started 21 bringing it back just to simulate an earthquake 22 because in earthquake, the rock motion will be in one 23 direction, and then it will be reversed and then go 24 into other direction. And it will go like that.
25 So this is the first stage. We did one NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
76 1 reverse to bring it close to the original point. And 2 as you can see, that building diverts, the joint 3 contracts, but never -- it covers all the dilation in 4 the first place because asperities have been sheared 5 off. They're not the same anymore.
6 Next slide, please.
7 We put a limitation and condition here 8 with the large site sample because as you can see in 9 those asperities and that -- could you go back two 10 slides, on that -- yes.
11 There had been a lot of asperities in the 12 rock joint surfaces. And if you take a small sample, 13 maybe half an inch, one inch, and do like this, there 14 is a possibility that a lot of things will be missed.
15 So we want to having large enough samples to capture 16 at least most of the features which are in the rock 17 joints.
18 Next slide -- next to the limitation and 19 conditions.
20 So during site-specific licenses, we'll 21 review the sample sizes, sample -- how it is collected 22 in the site, how the samples have been developed, 23 tested, the test results, and how those were --
24 parameters have been derived from those two curves I 25 just showed in the previous slide. You can get all NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
77 1 those parameters from those two curves.
2 MEMBER HALNON: So, Amit, this is Greg 3 again. If a site was going to do this on an existing 4 nuclear facility, large light-water reactor, am I 5 reading that they would have to do additional samples 6 and couldn't take credit for the seismic configuration 7 nor the soil configuration already established at 8 that --
9 MR. GHOSH: Yes. See, they have done, 10 probably, for the soil, but they haven't done for the 11 rock. And the rock has fractures that hasn't tested.
12 So they need to test this --
13 MEMBER HALNON: Okay.
14 MR. GHOSH: -- because without these test 15 results, the model -- as good as it is, it doesn't 16 make any difference.
17 MEMBER HALNON: All right. Thank you.
18 MR. GHOSH: Thank you, sir.
19 Next slide, please.
20 In my opinion, this is the most difficult 21 part of the testing and most important part, the 22 stable reactor shaft. The reactor shaft includes --
23 this is a very poor way of showing because I can't get 24 inside the rock and see this. So I am showing it 25 around the surface, that we have excavated this shaft.
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78 1 You can see the very small blocks at the 2 site, which happens in every project. They will try 3 to (audio interference) because that has space enough 4 for them to move in. And these are very small 5 compared to what we are doing, doesn't bother, except 6 we don't want the workers to get injured. So either 7 there will be a temporary support or they will be 8 excavated and all.
9 And nobody takes them into account in 10 designing and all because this is part of the 11 construction process. But that doesn't mean we want 12 to have a very large block or large region or lots of 13 blocks sliding into that because there is an opening 14 -- the later one.
15 This -- and that thing, if it starts 16 coming out, that gets really bad because we don't want 17 that. The GEH has proposed not to use the permanent 18 support. See, if you look into the Washington, D.C.
19 Metro, if you are inside the tunnel, many places you 20 will see there is a shotcrete, liquid concrete, which 21 has been spread over that just to get the small blocks 22 not to fall onto anybody.
23 But during any of the -- I mean, at the 24 Metro stations, you have heavily supported because 25 that's what the (audio interference) support system is NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
79 1 that nobody wants an unstable block to fall. But 2 there was a case in the Boston Big Dig Tunnel. One of 3 the supportive blocks fell and killed a motorist.
4 That became big, big news and issue with that.
5 So nobody wants that thing happen, and 6 especially when we have a nuclear reactor in there.
7 And GEH has proposed -- want to use permanent support 8 there, which makes sense because once that support 9 system and reactor has been placed, the permanent 10 support may not be accessible, and which time for 30, 11 40 years it is very difficult to get into the support 12 system, which continue to function at that level when 13 it was installed, at time zero.
14 So they want to figure it out: is there 15 any unstable blocks in the surrounding medium that 16 could be affecting the nuclear reactor? There are 17 several ways to figure it out. One is this very 18 classic key block theory, very elegant solution 3D 19 geometry problem by Professor Goodman and Gen-hua Shi 20 at the University of California, Berkeley.
21 Or you can do some numerical simulation, 22 like you can use the (audio interference) model if you 23 had got all the fractures information in there. Once 24 you do that analysis, it will show which block or 25 blocks have a tendency to slide in which direction and NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
80 1 what it can be -- I mean, then you decide what needs 2 to be done.
3 Additionally, they have said that there 4 will be instrumentation installed around the shaft.
5 And so they can verify these true results, numerical 6 simulation and the results, to get a good confidence 7 that yes, they have found some unstable (audio 8 interference) and then act accordingly.
9 CHAIR MARCH-LEUBA: Can I ask you a 10 question about this?
11 MR. GHOSH: Yes, sir. Please.
12 CHAIR MARCH-LEUBA: Is this 13 instrumentation during construction, or is this an 14 addition that should last 80 years?
15 MR. GHOSH: This should last from 16 construction to the end of the reactor life because 17 they should have -- or, it may be the place may be 18 maintained, but they need, should have instrumentation 19 because to understand is there anywhere instabilities 20 growing with time. And I --
21 (Simultaneous speaking.)
22 CHAIR MARCH-LEUBA: So you have 23 instrumentation, will require power and maybe embedded 24 down a hundred feet down the (audio interference)?
25 MR. GHOSH: Some of them may require power NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
81 1 but most of them, like, you know -- I'm forgetting the 2 word -- but it is like a rock bolt, it's like a long 3 rod with several sleeves over it, and how the sleeves 4 are anchored at different locations and which time is 5 that is the moment that you can, this mechanical 6 device can measure that and give you an indication.
7 And basically you can put -- and now it is 8 with the advanced electronics, a lot of things can be 9 done. And they need not be from the reactor shaft, 10 can be from the top surface in the bore holes.
11 CHAIR MARCH-LEUBA: Okay. And those 12 instruments will be at the minimum audited during the 13 final implementation before a license is issued for a 14 site-specific location?
15 MR. GHOSH: Yes, sir.
16 CHAIR MARCH-LEUBA: Thank you.
17 MR. GHOSH: They have to be because, yes.
18 Next slide, please?
19 MEMBER BROWN: Can you leave it there for 20 a minute?
21 MR. GHOSH: Sure.
22 MEMBER BROWN: This is Charlie Brown, got 23 a question.
24 MR. GHOSH: Yeah.
25 MEMBER BROWN: Go back, please.
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82 1 PARTICIPANT: The other way.
2 MEMBER BROWN: Thank you. At least, this 3 is rock, it looks -- even though there's all the sheer 4 -- all the planes that you show at an angle, are there 5 any criteria relative to non-uniformities?
6 For instance, if you came down 20 feet and 7 all of the sudden there was a, another 20 feet of 8 soil, different type of soil, clay or something, then 9 you go down another 20 feet and you find another set 10 of rock layers, and then you go down another 20 feet 11 and you find -- I mean, solid rock layers -- and you 12 go down and you find crushed rock layers.
13 Is there any criteria that you use for 14 saying in these bore holes, when you do it around the 15 area that you're interested in, that say, no, you 16 can't build here? Is there something built into your 17 all's evaluation?
18 MR. GHOSH: Yes. So, if you say, first 20 19 feet you have fractured rock, then next 20 feet is 20 some kind of soil, right? So there you'll have an 21 interface between the soil and the rock and the soil 22 parameters.
23 So soil parameters we will be 24 characterizing using the traditional ways, the rock 25 they will be characterizing with all this fracture NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
83 1 mapping and in site stress fail and their strength 2 determination.
3 So in the model we can have two types of 4 material, the (audio interference) can't take the 5 materials because now it is -- it's just changing the 6 material properties in the elements, and give 7 appropriate -- the interface values as given in that 8 figure 4-2.
9 So we'll have different values for (audio 10 interference) and sheer stiffness, normal stiffness, 11 and those strength parameters appropriate for that 12 soil and rock interface. So there is no restriction 13 on that.
14 MEMBER BROWN: So, what you end -- the way 15 I would read your comment then, there's no restriction 16 but that sounds like you would have to have a 17 recognition of the different stresses as you go down, 18 and it would change the construction of that shaft or 19 do you make the whole shaft uniform just to handle the 20 weakest area?
21 MR. GHOSH: No, the shaft should be as it 22 is in the field, as measured, as monitored, as in the 23 field, like, exactly all the layers of rock or soil, 24 and their interfaces.
25 MEMBER BROWN: But you can handle that is NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
84 1 what you're saying --
2 MR. GHOSH: You can handle that, yes.
3 MEMBER BROWN: Okay. All right, thank 4 you.
5 MR. GHOSH: You are welcome, thank you, 6 sir. Next slide, please.
7 So we'll have several excavations and it 8 has to be self-supported, that means there's no --
9 permanent support to be used. We are not talking 10 about in the temporary reinforcement.
11 Some cases, it is like instead of --
12 permanent support, like, if it is possible, given the 13 circumstances, that it can be over-excavated, the 14 shaft, because there's some loose pockets around. And 15 then fill it up with backfill of some cement material, 16 concrete, which is generally allowed, acceptable. In 17 the analysis we have to have appropriate properties 18 for those radiants.
19 So in the site-specific application we'll 20 review how they are identified, the unstable rocks or 21 radiants and to assess the -- pressure imparted by 22 them because they are assuming it is zero.
23 So we'll check those things in the site-24 specific application so that we understand that our 25 shaft will be stable in reality.
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85 1 CHAIR MARCH-LEUBA: Let me ask a question 2 that might be above your pay grade.
3 MR. GHOSH: Yes, sir.
4 CHAIR MARCH-LEUBA: You used the word 5 review as opposed to audit, in my mind an audit means 6 you are approved to do what we approved in this 7 topical report, unless we find something wrong in the 8 audit.
9 A review implies you cannot proceed until 10 you have a piece of paper from us, like a safety 11 evaluation in the future. Do you mean review in this 12 sense or do you mean, we'll look at it and review part 13 of the licensing process?
14 MR. GHOSH: Yes, I mean the one that you 15 just said, part of the licensing process. Review it, 16 and in that case, I also, like, when you're auditing, 17 we are also reviewing what they're presenting and they 18 have in their analysis, laboratory test and any --
19 CHAIR MARCH-LEUBA: So, administratively, 20 you don't expect a topical report revision two issued, 21 or you to review on a safety evaluation report 22 associated with it. It would be part of the licensing 23 process, more like an audit. Like --
24 (Simultaneous speaking.)
25 MR. GHOSH: Yes.
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86 1 CHAIR MARCH-LEUBA: You are approved 2 unless we find something wrong?
3 MR. GHOSH: Yes.
4 CHAIR MARCH-LEUBA: Okay. Thank you.
5 MR. GHOSH: Yes, because a lot of things 6 will be site-specific. Thank you, sir.
7 MEMBER HALNON: Amit, this is Greg. I 8 think the excavation process is going to be of great 9 interest because GE mentioned that it could be -- the 10 water table could be higher than the bottom of the 11 reactor building.
12 Are there techniques out there to be able 13 to dig down and de-water a huge pit like this so you 14 can start pouring concrete appropriately, and 15 backfilling as necessary, like you mentioned?
16 MR. GHOSH: Yes, sir. One of the thing is 17 like, you know, if there's a water table isn't, or 18 doesn't give you much of water, like, you know, small 19 amount of water, you can waterproof it, or you can 20 freeze the surrounding areas so that it doesn't flow 21 in there, and you could do the excavations and then 22 you waterproof the shaft, the cylindrical areas.
23 MEMBER HALNON: Okay --
24 (Simultaneous speaking.)
25 MR. GHOSH: Yes, there are practical NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
87 1 areas, like, I'll give you examples, like, when you do 2 the Metro tunnels, very close to, say, the Washington 3 -- I mean, Washington -- I mean Potomac River, yes, 4 they faced all those things in there.
5 MEMBER HALNON: Okay. So the temporary 6 reinforcement mitigation measures are, they're not 7 going to be exotic, they're well-established. I see 8 one of your colleagues over here saying this --
9 MR. GHOSH: Yes.
10 MEMBER HALNON: Agreeing with that, so, 11 okay. All right, thanks.
12 MR. GHOSH: Next slide, please. Okay, now 13 I talk about soil structure interaction modeling, 14 which is very routinely done for, in the nuclear areas 15 or where there's earthquake is a problem in a single 16 structure.
17 So, here we have an embedded reactor shaft 18 surrounded by a media and we need to -- while you do 19 it so that we understand how much a load will be given 20 on the particulates component of the reactor.
21 So that we can design it against, for that 22 load, design load, have enough capacity with the 23 reinforcement requirement and do in-structure response 24 spectrum. And they will be doing a one-step analysis 25 as given in the American Society of Civil Engineer NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
88 1 Standard 4-16, which is an industry standard, and our 2 NUREG 0-800 is also, use that part of it.
3 And they will be using the SASSI code, 4 System for Analysis of Soil Structure Interaction 5 computer code to do this analysis in a computationally 6 efficient way, because we have to do a lot more, a lot 7 many runs and all, that such an assumption are 8 generally taken -- and that's part of the SASSI code 9 too -- that subgrade material is continuous, that 10 means no more fractures, all the fractures have been 11 somehow subsumed in the material properties, their 12 effect.
13 Then the material is isotropic and 14 linearly elastic, so there is no nonlinearity of the 15 reactor surface and the surrounding medium.
16 When I use soil, it's a generic term now 17 because soil can be rock, or soil and rock, so.
18 And there is no static lateral pressure 19 because we have established that the shaft will be in 20 a self-supported rock medium or soil medium. Next 21 slide, please.
22 So soil -- we have used it for many, many 23 nuclear projects, how to get the soil elastic modulus, 24 staff has experience, industry has experience. We use 25 the standard cone penetration test, pressure meter.
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89 1 There are ASTM standards how to get this 2 elastic modulus on this test at the site, so I will 3 not deal with that in here.
4 For the rock, it is a function of the 5 intact rock modulus, rock fracture network because, as 6 you have seen in that picture, that the rock fracture 7 really controls the behavior of the rock mass because 8 all of the rock may be very strong, but the fractures 9 are weak, open, so they really control how the rock 10 mass gives under any load.
11 To use this develop -- the, you know, 12 mining and construction industry has developed rock 13 mass classification schemes, like rock mass rating, 14 RMR values, by Z.T. Bieniawski or Geological Strength 15 Index by Hoek and Brown.
16 They collected the behavior of rock mass 17 from different projects all over the world and tried 18 to use some parameters to develop one rating system, 19 so that in a new project we can classify the rock as 20 very strong, strong, and understand what possible 21 behaviors they may have.
22 So, each of them incorporates this rock 23 fracture information at the site, and there are other 24 parameters, we give it a numerical rating to that, and 25 at the end we add them together to get the final NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
90 1 rating of the site.
2 So this sort of helps the design engineer 3 to translate their experience all over the world, and 4 if a similar fractured rock mass into the project.
5 And then, using this intact -- sorry --
6 using this rock mass classification number, or rating, 7 there are many empirical equations to develop or 8 estimate the rock mass modulus, and these are 9 empirical equations so, there are many, so in this 10 LTR, GEH has given for, using the RMR, and I saw one 11 paper where there are more than 30 they collected, 12 like, empirical equations, so we need to figure it 13 out.
14 When the ones they have given by -- if 15 they work -- have been used in different rock medium, 16 so one of the -- and you get at the end, what is the 17 elastic properties, elastic modulus of the rock mass, 18 one number, that means it becomes an isotropic medium, 19 we assume that is an isotropic medium.
20 Now, just assuming we have a rock mass 21 with a lot of horizontal bedding planes, like, lots 22 of, is a bedded deposit. Deposited at, in geological 23 time, different types of rock.
24 So only horizontal planes, several of 25 them, so the elastic modulus, the compliance how stiff NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
91 1 all the material is will be different across the 2 vertical direction than in the horizontal direction, 3 because we have these fracture planes in there.
4 But this approach gives an isotropic 5 medium, that means it's uniform all over. Next slide, 6 please.
7 So that's what leads to the Limitation and 8 Condition number three, that you need site-specific 9 licensing application, the staff will review whether 10 the fracture network present at the site can make this 11 rock mass isotropic, behave like an isotropic 12 homogenous medium.
13 So we'll review that so that we understand 14 whether these empirical equations can be used in a 15 real case, a site-specific licensing case. Next 16 slide, please.
17 The strain-compatible sub-grade dynamic 18 properties, which we'll use as an input to the SSA 19 site, Soil Structure Interaction Analysis, they need 20 to be consistent with the soil or rock properties used 21 in generation and input motion because SSA Analysis is 22 a deterministic, and site response analysis is 23 probabilistic, that needs to be the same -- as given 24 in Reg Guide 1.208 and NUREG/CR-6728.
25 Just using the confirmed motion based on NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
92 1 generic rock site may not result in strain-compatible 2 properties.
3 GEH has proposed an approach to develop 4 that has a consistent strain-compatible properties 5 consistent with the observed ground motion. They have 6 assumed the strain-compatible properties are 7 approximately log normally distributed, which for us, 8 parameters, (audio interference), parameters are soil, 9 rock related parameters, generally this is true. Next 10 slide, please.
11 This approach seems reasonable but this 12 will be a first of our application to a nuclear 13 project, so in a site-specific application we'll audit 14 this to get a very good understanding of the use of 15 this approach. Next --
16 (Simultaneous speaking.)
17 MR. SHULTZ: Amit --
18 MR. GHOSH: Yes, sir?
19 MR. SHULTZ: Before you leave this slide on 20 the Condition four -- this is Steve Shultz, given the 21 experience that you and the team has had with this and 22 the reviews that have been done now, would you think 23 it would be right to develop the audit plan in some 24 level of detail at this point in time?
25 In other words, to say, we're going to NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
93 1 audit this later on, may not ask the right questions, 2 may not be a scope of review that would be 3 appropriate, and some direction now could really help 4 both, the Applicant and a future licensee to 5 understand in more detail what is expected, especially 6 with the first ever application to a reactor project.
7 MR. GHOSH: At this level, in this LTR, 8 this is given at a high level that will be having this 9 normal, log normal distributions, and how the 10 epistemic uncertainties will be addressed in the --
11 but this is, like, a theory.
12 So when the real application comes in, the 13 site-specific application, we like to understand this 14 theory and see how that has been implemented.
15 So, in my opinion, once we have a much 16 deeper information, detailed information, we will be 17 able to write a audit plan, do the audit, and then 18 maybe use that as a template for future application.
19 MR. SHULTZ: I was thinking of not 20 something within the safety evaluation but a separate 21 document that could capture the focus of the review 22 that you're going to be doing in the future.
23 You seem to know it all, in terms of the 24 overall evaluation but it also involves a number of 25 different disciplines to put that audit plan together NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
94 1 appropriately.
2 MR. GHOSH: Yes, sir.
3 MR. SHULTZ: Something that might be 4 considered.
5 MR. GHOSH: Okay, thank you.
6 CHAIR MARCH-LEUBA: This is Jose, and I 7 think that's an excellent suggestion because we've 8 been doing reviews, and it is often that we hear, the 9 person that did the review just retire and I cannot 10 give you all the details.
11 So, I'm not urging you to retire, but 12 whenever this audit plan comes along, will you be 13 around? So it really would be helpful to have an 14 informal audit plan, certainly not modified SER.
15 I think it's a good --
16 (Simultaneous speaking.)
17 MR. SHULTZ: That's what I was thinking, 18 not something in detail, that would be developed later 19 for the specific application, but just the general 20 sense of what the expectations would be.
21 MR. GHOSH: (Audio interference) so that 22 in a future application time, we don't forget that's 23 why we have a limitation and condition in place, so 24 that future reviewer will be directed to do this so 25 that it doesn't get lost.
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95 1 CHAIR MARCH-LEUBA: Okay, you can 2 continue.
3 MR. GHOSH: Thank you. Next slide, 4 please.
5 And I'll discuss briefly about the 6 nonlinear soil structure interaction analysis because 7 one of the assumption was, everything is linear, if 8 there is a site which has a very high seismicity or 9 the material, subgrade materials are highly nonlinear, 10 will that -- but that may not -- area to the linear 11 assumptions.
12 Like, if there's a separation of the 13 reactor building with the surrounding media, soil 14 separation, all the rock fractures have very highly 15 nonlinear, how they respond to the earthquake.
16 So GEH would tried to do a sensitivity 17 nonlinear site-specific -- soil-structure interaction 18 analysis and following the national standard -- ASCE 19 4-16, appendix B.
20 One thing is that nonlinear SSA analysis 21 is quite complex and -- next slide, please.
22 So in a site-specific application, if we 23 see there is a nonlinear SSA analysis has been 24 presented, we'll review how the nonlinear area has 25 been characterized, how they have been modeled, and NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
96 1 then how they have been -- put into the SSA analysis.
2 So we'll be doing a much more in-depth 3 review for this if we see nonlinear SSA analysis, 4 because this all (audio interference).
5 Next slide, please.
6 So, in conclusion, staff finds the 7 approaches proposed to characterized the surrounding 8 media is reasonable, are reasonable, the staff finds 9 the approaches proposed to develop the site design 10 parameters are reasonable.
11 And we have placed five Limitation and 12 Conditions to have a more in depth review of the 13 background information, and relevant design and site 14 information, characterization of the surrounding 15 media, and development of the site design parameters 16 associated with them.
17 With this, I conclude my presentation, and 18 any questions?
19 CHAIR MARCH-LEUBA: Members, any 20 additional questions for the staff?
21 MR. SHULTZ: Amit, this is Steve Shultz --
22 (Simultaneous speaking.)
23 MEMBER DIMITRIJEVIC: This is Vesna --
24 (Simultaneous speaking.)
25 MEMBER DIMITRIJEVIC: I have a question, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
97 1 what is your opinion on how would this affect, I mean, 2 you know, I'm so, just listening to all of this and 3 how it has changed some seismic risk perspective. So 4 what do you think, how will this affect the seismic 5 PRA and estimates, and maybe even seismic 6 qualification, what will be different from how the 7 things are done now?
8 MR. GHOSH: If I understand your question, 9 like, how -- what will be the different in a seismic 10 PRA of this --
11 MEMBER DIMITRIJEVIC: Yeah, I heard in the 12 previous thing, the risk would be lower with this 13 structure, the seismic risk will be lower, but I'm not 14 sure what is that based on.
15 And it seems to me, since this is now much 16 more site-specific than just seismic, you know, 17 because it strongly depend on the materials, so my 18 question is, did you, you know, did you have any 19 thoughts how would this impact the seismic risk 20 assessment?
21 (Simultaneous speaking.)
22 MEMBER DIMITRIJEVIC: The seismic 23 qualification even, you know, will you qualify also 24 for the soil structure, I mean, I'm not sure. I'm a 25 little -- did not have time too much to think about NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
98 1 that, so I'm just, like, could use what are your 2 thoughts on it.
3 MR. GHOSH: At this moment, what I can 4 tell you, like, the seismic fragility of any component 5 on a structure, that depends on what it is 6 experiencing and this, one thing, it has been observed 7 that if you go below the surface, your seismic 8 response may be lower.
9 But, at the same time, we have all these 10 fractures which work quite differently, so very 11 difficult to say whether the seismic risk will go up 12 or down, and this has to be analyzed for seismic 13 fragility of each of the important to safety 14 components, they need to be analyzed.
15 So once they develop an estimate, what is 16 the ground motion there, or seismic motion, there is 17 a component is going to experience that ISRS, in-18 structure response spectra and others, then they can 19 use that to develop the seismic fragility from there.
20 But, at this moment, I don't know more 21 than that, whether it would be -- how to do it 22 differently rather than the very standard way.
23 MEMBER DIMITRIJEVIC: Because you know 24 that one of the standard things is now, in the design 25 applications they do the seismic margin assessment NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
99 1 which the components are qualify for this, you know, 2 certain ground motion then now detailed seismic --
3 this thing, every (audio interference) extent of 4 hazards, you know, but makes the seismic much more 5 prominent, you know.
6 MR. GHOSH: Yes --
7 MEMBER DIMITRIJEVIC: So I'm sort of very 8 curious, you know, what is going to be different, so.
9 MR. GHOSH: It's business to be worked out 10 and my knowledge doesn't go in there, I am so sorry.
11 MEMBER DIMITRIJEVIC: Thank you.
12 MR. GHOSH: Thank you.
13 MEMBER DIMITRIJEVIC: I think everybody's 14 thinking, in the thinking phase when comes to that but 15 far from the, having the real solution, so.
16 MR. SHULTZ: Amit, this is Steve Shultz.
17 MR. GHOSH: Hi.
18 MR. SHULTZ: I have just a general 19 question or comment, as you introduced the discussion 20 this morning, and as the GEH has also presented at the 21 end of their presentation, there's a lot of detail in 22 the overall evaluation that is proposed and reviewed.
23 And many of the approaches that have been 24 proposed, you listed on a slide, saying, we're not 25 going to discuss those today but they are discussed in NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
100 1 the safety evaluation.
2 But my general question is, your statement 3 that the approaches are reasonable, I'm thinking back 4 to that list of questions that you proposed at the 5 beginning of the presentation, or at the beginning of 6 your review, I thought they were very good questions.
7 Have those questions been adequately answered in your, 8 and the teams, view for all of the approaches that 9 have been proposed by GEH, can we take that away from 10 your review?
11 You've got the second bullet in the last 12 slide you have, we found the approaches to be 13 reasonable, is that a global statement for what GEH 14 has proposed?
15 MR. GHOSH: Yes, this is a global 16 statement, like, I mean, all the approaches, you know, 17 are reasonable because they has been used before or 18 somewhere in the nuclear application or other 19 industries.
20 When there is other industry, like, I'll 21 give you one example with the mining industry, their 22 definition of a stable excavation would not be proper 23 for a nuclear application.
24 Because, say, in a mining, they want to 25 excavate the material, they don't want to be stable NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
101 1 for years and years and years, because they want to 2 extract the whole body of the rock, take it to the 3 mill and get the metal or mineral out, and sell it.
4 So they want the excavation to be stable, 5 only until they mine it out, which is maybe one to two 6 years. Whereas we are talking 40 years, so some of 7 the tolerance level that their definition do not 8 easily translate.
9 So, yes, when we found only used in 10 mining, we need to do a lot more work in the nuclear 11 area because we don't -- that definition -- so it give 12 a confidence if method works, but gives us a -- that 13 we need to do a lot more homework when we do the 14 actual review.
15 And, see, there's some cases we found, 16 like, we need to have this limitation and conditions 17 because, like, say, stable excavations which is very 18 good but it's a very difficult to show that, what are 19 the ways to show that, it took us a lot of analysis.
20 So that the whole concept -- how do I say 21 that -- doesn't get lost during the actual review, we 22 put those things that we have a list of items to be 23 reviewed in detail, so that we go into the background, 24 develop and designing site information, 25 characterization, and site design parameters.
NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
102 1 We do much more in depth review at least 2 on those areas, and it may so happen in a site-3 specific applications we may find something else is 4 also important.
5 MR. SHULTZ: You have identified those in 6 the Limitations and Conditions, thank you for bringing 7 your expertise to both, the review and also to the 8 presentation today. It was very enlightening, thank 9 you.
10 MR. GHOSH: Thank you, sir. I appreciate 11 it very much, thank you.
12 CHAIR MARCH-LEUBA: I don't see any more 13 questions coming so, with that, we are going to have 14 to open the floor for comments from the public.
15 Anybody on the conference call that wants 16 to make a comment can do it now, if you are on Teams 17 just unmute yourself, if you're using the conference 18 phone line you need to use star-six.
19 (No audible response.)
20 CHAIR MARCH-LEUBA: Just a reminder that 21 the open comment portion of the meeting is an 22 opportunity to add comments to the public record for 23 committee consideration.
24 If you have any questions or particular 25 requests, please address them directly to our DFO, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
103 1 Kent Howard, his email is kent.howard@nrc.gov.
2 So do we have any members of the public 3 that want to place some comments on the record?
4 I don't hear anybody, so, with that, let 5 me remind you that we are scheduled to have a full 6 committee meeting for this topic in a couple of weeks, 7 April 7, I believe, and scheduled to write a letter.
8 We will also have another BWRX-300 topical 9 report review this afternoon on containment, and we 10 are also scheduled to write a letter on that.
11 That said, unless anybody has anything 12 else to add?
13 MEMBER HALNON: Yeah, I just wanted to add 14 -- this is Greg -- to Steve's comment, appreciate both 15 the staff and GE. Very good presentations, brought 16 the right people, answered questions to us in layman's 17 terms, so I appreciate that very much.
18 (Simultaneous speaking.)
19 MEMBER BROWN: I would also comment and 20 echo Greg in that it's nice to see, get the 21 explanations see -- the NRC has.
22 CHAIR MARCH-LEUBA: Yeah.
23 MEMBER BROWN: A very talented and capable 24 group with which to address these types of issues.
25 That was a illuminating discussion, so much NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
104 1 appreciated for those of us who are not steeped in 2 this lore. So thanks again.
3 CHAIR MARCH-LEUBA: I have time to think 4 and there is another topic preparation for the full 5 committee, we have almost every member present in this 6 subcommittee, only one member wasn't present, so the 7 primary purpose of the full committee presentations is 8 for the benefit of the public, so --
9 (Simultaneous speaking.)
10 CHAIR MARCH-LEUBA: And Walt, yeah, two.
11 Yeah, two members were not here.
12 But the primary purpose of the full 13 committee is for the benefit of the public, so keep 14 the presentations at the higher level and cut them 15 down a little bit in time, I'll leave it to your 16 discretion.
17 Because we like to use additional time to 18 read our letter and work on our final product, which 19 is the letter. Speaking of which, I will be sending 20 a draft letter sometime next week to the staff for 21 proprietary review, even though this LTR has no 22 proprietary items, it's always good to make sure we 23 verify it, so we will be asking the staff and GE to do 24 a quick turnaround on that proprietary review, because 25 we don't have much time, and I see Mike saying yes.
NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
105 1 Hey, Mike, while I have you here -- I 2 thought you were not on the call anymore -- let me 3 bring up another topic, see how the members feel about 4 it and you feel about it, when we do the sign center 5 reviews, like on new reactors, often we write one 6 letter for two or three chapters, today we are going 7 to review two topical reports and my plan was to write 8 two letters, but maybe in the future or even for 9 today, we could write one letter for two topical 10 reports. Would that be a problem?
11 MR. DUDEK: So there are two independent 12 topics and two independent topical reports, I would 13 leave that up to the description of the committee.
14 I mean, you're the experts, but I could 15 see how there could be complications with combining a 16 letter on two independent topics, even though they're 17 presented on the same day. We'd want to explore that 18 a little bit, I think.
19 CHAIR MARCH-LEUBA: I was -- yes, I mean, 20 the letters are going to have to have, and will have 21 some commonality, description of what is BWRX-300 and 22 this and that, but I can see why you would like to 23 have it separate so that it's attached to the SER, so.
24 MR. DUDEK: Yeah.
25 CHAIR MARCH-LEUBA: Going forward we'll NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
106 1 assume we want one letter for every topical report 2 unless we hear otherwise.
3 MR. DUDEK: I think that's a good 4 assumption.
5 CHAIR MARCH-LEUBA: Yeah, understanding 6 that the ACRS has their own mind and we decide what we 7 want to do, but --
8 (Laughter.)
9 CHAIR MARCH-LEUBA: Okay. Any more 10 topics?
11 With that, then meeting is adjourned.
12 And we'll see almost everybody here this 13 afternoon at 1:00 O'clock.
14 (Whereupon, the above-entitled matter went 15 off the record at 11:10 a.m.)
16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
GE Hitachi Nuclear Energy George E. Wadkins GE-Hitachi Nuclear Energy Americas, LLC Vice President, New Power Plants and Products Licensing 3901 Castle Hayne Road Wilmington, NC 28402 USA T 910.200.3295 George.Wadkins@ge.com M220047 March 22, 2022 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555-0001 Canadian Nuclear Safety Commission 280 Slater Street P.O. Box 1046, Station B Ottawa, Ontario, K1P 5S9, Canada
Subject:
Final ACRS Subcommittee Presentation Slides for NEDO-33914, BWRX-300 Advanced Civil Construction and Design Approach Licensing Topical Report Enclosed are the final presentation slides that GE Hitachi Nuclear Energy (GEH) presented during the Advisory Committee on Reactor Safeguards (ACRS) subcommittee meeting on March 18, 2022. These final presentation slides include the addition of the back-up slide presented during the meeting. These slides support the ACRS review of NEDO-33914 Revision 1, BWRX-300 Advanced Civil Construction and Design Approach, and the corresponding Advanced Safety Evaluation Report (SER) with No Open Items. contains non-proprietary information and may be made available to the public.
If you have any questions, please contact me at 910-200-3295.
Sincerely, George E. Wadkins Vice President, New Power Plants and Products Licensing GE-Hitachi Nuclear Energy Americas, LLC
Enclosure:
- 1. Final ACRS Subcommittee Presentation Slides for NEDO-33914, BWRX-300 Advanced Civil Construction and Design Approach Licensing Topical Report - Non-Proprietary Information
M220047 Page 2 of 2 cc: James Shea, US NRC Document Components:
001 M220047 Cover Letter.pdf Chantal Morin, CNSC 002 M220047 Enclosure 1 Non-Proprietary.pdf PLM Specification 006N9431 Revision 2
ENCLOSURE 1 M220047 Final ACRS Subcommittee Presentation Slides for NEDO-33914, BWRX-300 Advanced Civil Construction and Design Approach Licensing Topical Report Non-Proprietary Information
ACRS Subcommittee Presentation GE Hitachi (GEH)
Licensing Topical Report (LTR) NEDO-33914 BWRX-300 Advanced Civil Construction and Design Approach March 18, 2022
Agenda
- Licensing Topical Report Purpose and Scope
- Regulatory Basis
- Investigations, Testing, Inspection and Monitoring Programs
- Foundation Interface Analysis
- Design Analyses
- Design Approach for II/I Interaction
- Generic Design Approach Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 2
BWRX-300 Buildings and Seismic Classification BWRX-300 Building Seismic Categories Reactor Building (SC-I)
Turbine Building (Non-Seismic)
Radwaste Building Control Building (RW-IIa)
(Non-Seismic)
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 4
BWRX-300 3D Section View Ground Level Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 5
Licensing Topical Report Purpose and Scope Licensing Topical Report Purpose GEH is seeking NRC approval for the application of an alternative approach to the construction, analyses, and design of the BWRX-300 below-grade Reactor Building.
The purpose of the LTR was to present design, analysis, and monitoring guidelines and requirements to support the request for NRC approval of the innovative and comprehensive construction approach for the construction of the below grade BWRX-300 small modular reactor (SMR) Reactor Building (RB) vertical right cylinder shaft (LTR Sections 1.3 and 1.4).
The following criteria, methodologies, recommendations, and approaches are addressed:
- Requirements and recommendation for site investigation and subsurface materials lab testing programs (LTR Section 3.1)
- Inspection and monitoring programs (LTR Sections 3.2 and 3.3)
- Compression strength testing program for safety-related concrete (LTR Section 3.2.2.1)
- Field monitoring program (LTR Section 3.4)
- Methods and approaches for non-linear Foundation Interface Analyses (FIA) (LTR Section 4.0)
- Requirements and recommendations for implementing a one step approach for static and seismic Soil Structure Interaction (SSI) analyses (LTR Section 5.1)
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 7
Licensing Topical Report Purpose
- Deterministic and probabilistic evaluation approaches to ensure the one step approach provides conservative design demands on the deeply embedded RB structure (LTR Sections 5.1.3 and 5.1.4)
- Approaches for developing equivalent linear static and dynamic subgrade properties used as inputs to the one step design analysis model (LTR Sections 5.2.1 and 5.2.4)
- Requirements and methodologies for developing Safe Shutdown Earthquake (SSE) design ground spectra to define the design ground motion along the depth of the RB embedment (LTR Section 5.2.2)
- Additional requirements for generating acceleration time histories for use as input to the seismic SSI analyses (LTR Section 5.2.3)
- Seismic SSI analysis approach that provides demands for seismic design and qualification of structures, systems and components (SSCs) for all frequencies of interest and adequately captures the effects of structure-soil-structure interaction (SSSI) for the deeply embedded RB with adjacent structures and foundations (LTR Sections 5.3, 5.3.2, and 5.3.7)
- Different approaches for demonstrating consistency between the results from the deterministic SSI analyses of the RB structure with the results from the probabilistic site response analyses (SRA) (LTR Section 5.3.4)
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 8
Licensing Topical Report Purpose
- Approaches for sensitivity evaluations from the effects of concrete cracking, soil structure interface conditions, soil separation and groundwater variations on the seismic response and design of the deeply embedded RB structure. (LTR Sections 5.3.5, 5.3.8, 5.3.9 and 5.3.10)
- Comprehensive approach for evaluating the effects of non vertically propagating seismic waves on the design ground motion and seismic response of the deeply embedded RB structure (LTR Section 5.3.3)
- Different approaches for considering Equipment Structure Interaction (ESI) for developing in structure seismic response demands for equipment design and qualification (LTR Section 5.3.6)
- Recommendations for performing non-linear seismic SSI analyses for sensitivity evaluations (LTR Section 5.3.11)
- Graded approach for the design of structures adjacent to the deeply embedded RB that includes Seismic Category II/I interactions (LTR Section 6.0)
- Methodology for developing generic seismic and geotechnical design parameters (LTR Section 7.0)
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 9
Licensing Topical Report Scope This request was supported by the following information in the LTR:
- Regulatory basis specific for the innovative approaches implemented for analysis, design and construction (LTR Section 2.0)
- Guidelines and requirements for characterizing subsurface conditions, including geotechnical site investigations and laboratory testing programs, as well as the inspection and monitoring programs performed during excavation, construction, and operation (LTR Section 3.0)
- Requirements and guidelines for performing FIA to ensure the stability of both structure and the in-situ soil and/or rock during and after construction (LTR Section 4.0)
- Design requirements, acceptance criteria and guidelines for the analysis and design of the deeply embedded RB, including the development of site specific geotechnical and seismic design parameters (LTR Section 5.0)
- An approach for addressing Seismic Category (SC) II/I interaction between the SC I RB and surrounding structures and foundations (LTR Section 6.0)
- Generic seismic and geotechnical design parameters (LTR Section 7.0)
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 10
Regulatory Evaluation Regulatory Basis - Defining Site Subsurface Conditions The approach used for defining and evaluating site subsurface conditions complies with the following:
- 10 CFR 100 requires the consideration of site physical characteristics, including seismology and geology.
- 10 CFR 100.20(c)(1) and 10 CFR 100.23 establish requirements for conducting site investigations for nuclear power plant license applications.
- IAEA Safety Guide NS-G-6 provides guidance on the methods and procedures for analyses to support the assessment of the geotechnical aspects for the design of nuclear power plants.
- NUREG-0800 (SRP) 2.5.4 provides regulatory guidance for the investigation and reporting site specific geologic features and characteristics of ground materials, including static and dynamic engineering properties and groundwater conditions (LTR Sections 3.1, 3.2, 3.3, 3.4, 4.0)
- RG 1.132, Site Investigations for Foundations of Nuclear Power Plants, Revision 2 describes methods acceptable to the NRC staff for conducting field investigations to acquire the geological and engineering characteristics of the site and provides recommendations for developing site specific guidance for conducting subsurface investigations. (LTR Sections 3.1, 3.1.1)
- RG 1.138 describes laboratory investigations and testing practices for determining soil and rock properties and characteristics needed for engineering analysis and design of foundations and earthworks for nuclear power plants. (LTR Section 3.1)
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 12
Regulatory Basis - Site Design Parameters The approach for defining and evaluating design parameters complies with the following:
- 10 CFR 100.23(d)(1) specifies the requirements for defining the safe shutdown earthquake (SSE) ground motion for the site and the need for addressing result uncertainties in the site investigation performed (LTR Section 2.1)
- NUREG-0800 (SRP) 3.7.1 provides regulatory guidance for the development of site design ground motion acceleration response spectra and time histories (LTR Section 5.2.3)
- RG 1.208, A Performance Based Approach to Define the Site-Specific Earthquake Ground Motion, Revision 0, specifies the performance-based approach Chapters 1 and 2 of ASCE/SEI 43 05 standard as an acceptable approach for defining the SSE Ground Motion Response Spectra (GMRS) that satisfies the requirements of 10 CFR 100.23.
- Interim Staff Guidance (ISG) DC/COL-ISG-017 Interim Staff Guidance on Ensuring Hazard Consistent Seismic Input for Site Response and Soil Structure Interaction Analyses, specifies the requirements for ensuring the inputs used for the deterministic SSI analysis of embedded structures are consistent with the results of probabilistic SRA used to develop Foundation Input Response Spectra (FIRS) and Performance Based Surface Response Spectra (PBSRS) (LTR Section 5.3.4)
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 13
Regulatory Basis - Seismic Analysis The seismic analysis complies with the following:
- 10 CFR 50 Appendix S, Earthquake Engineering Criteria for Nuclear Power Plants
- SSI analyses:
- SRP 3.7.2
- ASCE/SEI 4-16, Section 5
- Finite Element (FE) Models:
- SRPs 3.7.1 and 3.7.2
- RG 1.61, Damping Values for Seismic Design of Nuclear Power Plants, Revision 1
- ASCE/SEI 4-16 Section 3 (LTR Section 5.1) and ASCE/SEI 43-05
- Effects of structure soil structure interaction (SSSI) of the RB with surrounding foundations:
- ASCE/SEI 4-16 Section 5.1.5 (LTR Section 5.3.7)
- SRP 3.7.2 Subsection II.3.B (LTR Section 5.3.6)
- Effects of non vertically propagating seismic waves, soil separation, concrete cracking and soil secondary non-linearity on the seismic response and design of the RB:
- ASCE/SEI 4-16, Section 5.1 (LTR Sections 5.3.3, 5.3.5, 5.3.8, 5.3.9, 5.3.10 and 5.3.11)
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 14
Regulatory Basis - II/I Interactions The approach used for evaluating the seismic category two over one interactions complies with the following:
- ASCE/SEI 43-05 (LTR Sections 6.2 and 6.3)
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 15
Regulatory Basis - Testing, Inspection and Monitoring The approach used for performing the testing, inspection, and monitoring complies with the following:
- 10 CFR 50 Appendix A GDC 1 inspection and testing requirements met by
- RG 1.142, Safety-Related Concrete Structures for Nuclear Power Plants (Other than Reactor Vessels and Containments)
- RG 1.136, Design Limits, Loading Combinations, Materials, Construction, and Testing of Concrete Containments,
- NRC Inspection Manuals 88131 (geotechnical and foundation), 88132 (structural concrete), and 55100 (structural welding)
- 10 CFR 50.65 requirements met by (LTR Section 3.3):
- RG 1.160, Monitoring the Effectiveness of Maintenance at Nuclear Power Plants,
- NUMARC 93-01 Industry Guideline for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants
- NUREG/CR-5738 (LTR Section 3.1.3)
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 16
Regulatory Basis - Summary
- The design and analyses described in the LTR comply with all applicable regulatory requirements and guidance as written.
- The implemented innovative approaches meet the intent of the current regulatory guidance for large light water reactors and address the specifics related to the seismic and structural design of deeply embedded SMRs (LTR Section 2.0).
- GEH is not requesting NRC approval for exemptions from any regulatory requirements or any exceptions to any regulatory guidance.
- The methodology in this LTR ensures safe operation of the BWRX-300 for the life of the plant.
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 17
Technical Evaluation Investigations, Testing, Inspection and Monitoring Programs
- Innovative property characterization and monitoring approaches driven by RB structure being deeply embedded
- Investigation, testing, inspection, and monitoring programs, in conjunction with the results of a set of FIA (LTR Section 4.3.4), ensure the safe siting of the BWRX-300 plant:
- Site investigation program (LTR Section 3.1.1)
- Subsurface material laboratory testing program (LTR Section 3.1.2)
- Construction and in-service monitoring programs (LTR Sections 3.2, 3.3, and 3.4)
- Excavation and foundation inspection and testing programs (LTR Section 3.2.1)
- Construction inspection and testing program for structural concrete (LTR Section 3.2.2)
- Compressive strength testing program of SR concrete (LTR Section 3.2.2.1)
- Structures Monitoring and Aging Management Program (SMAMP) in-service condition monitoring (LTR Sections 3.3.1 and 3.3.2)
- Field instrumentation plan (LTR Section 3.4)
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 19
Foundation Interface Analysis
- To ensure structures and supporting media, soil, and/or rock meet stability requirements of SRP 2.5.4.
- Results of FIA used to evaluate construction plans, including possible ground improvements, excavation support and foundation interface design. Also used for verification of the RB shaft design.
- Non-linear constitutive 3D FIA numerical model (LTR Sections 4.1 and 4.2)
- Analysis approach includes interface modeling, structural modeling, fluid soil interaction, and consideration of all plant life stages (LTR Section 4.3.1 - 4.3.4)
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 20
Foundation Interface Analysis Innovative approach implemented for the BWRX-300 FIA beyond the current regulatory guidance of SRP 2.5.4
- General modeling and analysis requirements for stability evaluations (LTR Section 4.1)
- Guidelines for modeling the non-linear constitutive response of soil and rock including the approach for calibrating the FIA model based on data obtained from field instrumentation (LTR Sections 3.4, 4.2.1 and 4.2.2)
- Guidelines for modeling interfaces, including contacts between structures and the subgrade, as well as interfaces between bedding units and other discontinuities in the geological formation (LTR Section 4.3.1)
- FIA structural modeling requirements, including recommendations for modeling SMR structures and soil stabilizations elements, such as rock anchors, soldier piles, and stabilization walls and liners (LTR Section 4.3.2) and beyond the current regulatory guidance of SRP 3.8.5
- FIA modeling approach for fluid soil interaction and FIA model calibration using measurements of groundwater elevations and hydrogeological investigations (LTR Sections 3.0 and 4.3.3)
- FIA approaches for the different BWRX-300 life stages, including guidelines for using the measurements from field instrumentation for FIA model calibration and benchmarking FIA results (LTR Sections 3.4 and 4.3.4).
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 21
Design Analysis
- Innovative static and seismic SSI analysis approaches for designing the deeply embedded RB structure (LTR Sections 5.1 and 5.3)
- Requirements, methodologies, and recommendations for developing site specific geotechnical and seismic design parameters are based on the results of site investigations and laboratory testing programs (LTR Sections 3.1 and 5.2)
- Requirements and recommendations ensure the seismic SSI analyses use input motion that is adequate throughout the depth of the RB embedment (LTR Sections 5.2.2 and 5.3.4)
- A comprehensive recommended approach for evaluating the effects of non-vertically propagating seismic waves on the design ground motion and seismic response of the deeply embedded RB structure (LTR Section 5.3.3)
- Recommends approaches for developing in-structure seismic response demands for equipment design and qualification, considering ESI (LTR Section 5.3.6)
- Introduces additional requirements for generating multiple acceleration time histories with refined time steps which ensures the mitigation of uncertainty in the computed structural responses (LTR Section 5.2.3)
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 22
Design Approach for II/I Interaction
- Graded approach for the design and II/I interaction evaluations of the structures adjacent to the deeply embedded SC I RB structure.
- Applies to the Control Building (CB), Turbine Building (TB) and Radwaste Building (RwB)
- CB, TB and RwB structures near the SC I RB are designed in accordance with their seismic classification (LTR Section 6.1)
- CB and TB: Non-seismic (LTR Section 6.1.1) - includes determination of seismic and wind design loads
- RwB: RW-IIa (LTR Section 6.1.2) - includes the determination of seismic, wind, tornado wind and missile design loads
- Approach for seismic II/I interaction evaluations of CB, TB and RwB structures, including criteria and recommendations for calculations of seismic stress demands and displacements (LTR Section 6.2)
- Approach for II/I interaction evaluations CB, TB and RwB structures for extreme wind loads, including criteria and recommendations for consideration of wind loads displacements (LTR Section 6.3)
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 23
BWRX-300 Generic Design Approach
- Methodology for development of generic seismological and geotechnical site parameters for the conceptual design of the BWRX-300 (LTR Section 7.0)
- Overall approach ensures a cost-effective design applicable for a wide range of site conditions (LTR Section 7.1)
- Use of Generic Design Response Spectra (GDRS) for the conceptual design seismic analyses of the RB (LTR Section 7.2)
- Use of generic subgrade dynamic properties for the conceptual design seismic analyses of the RB (LTR Section 7.3)
- Use of generic static properties for different subgrade materials considered for the conceptual design, which are correlated to the generic dynamic subgrade profiles to develop generic profiles of static subgrade properties for use as input for the conceptual design static SSI analyses (LTR Sections 7.4 and 7.5)
- Use of friction coefficient values and groundwater table elevations for the generic conceptual design evaluations (LTR Sections 7.6 and 7.7)
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 24
Conclusion In summary
- The design and analyses described in the LTR comply with all applicable regulatory requirements and guidance as written.
- The innovative approaches meet the intent of current regulatory guidance for large light water reactors and address the specifics related to the seismic and structural design of deeply embedded SMRs.
- GEH is not requesting NRC approval for exemptions from any regulatory requirements or any exceptions to any regulatory guidance.
- The methodology in this LTR ensures safe operation of the BWRX-300 for the life of the plant.
Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 25
Questions or Comments Back-up Slides BWRX-300 Monitoring, Analysis and Design Process FIA - Foundation Interface Analysis Ground SRA - Site Response Analysis Basecase Models Motion DRS Probabilistic and ATHs Linear DRS - Design Response Spectra of Small Strain Equivalent Seismic ATH - Acceleration Time History Dynamic Soil and Linear SRA Response Rock Properties Strain SSI - Soil-Structure Interaction SSI Analyses Compatible Site Soil Profiles Investigations Equivalent Linear Linear Field and Static Soil and Elastic 1-g Laboratory Rock Properties SSI Analyses BWRX-300 Tests RB Design Non-Linear Soil and Rock Constitutive Earth Model Parameters Pressure Excavation, Load Construction Validations Sensitivity and In-Service Non-Linear Non-Linear Monitoring FIA Seismic SSI Programs Analyses Copyright 2022 GE Hitachi Nuclear Energy Americas, LLC - All Rights Reserved 28
Staff Presentation to the ACRS Sub-Committee GEH Licensing Topical Report BWRX-300 Advanced Civil Construction and Design Approach (NEDO-33914, Revision 1)
MARCH 18, 2022
Topical Report Review Chronology
- GEH submitted licensing topical report (LTR) NEDO-33914, Revision 0, BWRX-300 Advanced Civil Construction and Design Approach, on January 20, 2021
- NRC issued requests for additional information (RAIs) 9849 and 9859 on July 19 and July 30, 2021, respectively
- GEH provided responses to RAI 9849 on August 19, 2021, and RAI 9859 on September 13 and November 4, 2021. The NRC staff found the responses acceptable.
- NRC issued the advanced safety evaluation on February 15, 2022 March 18, 2022 GEH BWRX-300 2
NRC Staff Reviewers:
- Amitava Ghosh, Ph.D., Geotechnical Engineer, Presenter, NRR/DEX/ESEB
- David Heeszel, Ph.D., Geophysicist, NRR/DEX/EXHB
- Edward Stutzcage, Health Physicist, NRR/DRA/ARCB
- Angelo Stubbs, Sr. Safety and Plant Systems Engineer, NRR/DSS/SCPB
- Sujit Samaddar, Sr. Structural Engineer, NMSS/DFM/MSB Project Managers:
- Alina Schiller, TR Project Manager, NRR/DNRL/NRLB
- James Shea, Sr. Project Manager, NRR/DNRL/NRLB March 18, 2022 GEH BWRX-300 3
Agenda
- Introduction
- Difference Between Traditional Light Water Reactor and GEH BWRX-300
- Regulatory Bases
- NRC Staff Major Reviewed Topics
- Other Reviewed Topics
- NRC Staff Review Strategy
- Rock Fracture Network/FIA Model/Limitation & Condition (L&C) #1
- Stability of Reactor Shaft/L&C #2
- Soil-Structure Interaction Modeling/L&C #3
- Strain-Compatible Subgrade Dynamic Properties/L&C #4
- Nonlinear Soil-Structure Interaction Analysis/L&C #5
- Staff Conclusions March 18, 2022 GEH BWRX-300 4
Difference Between Traditional Light Water Reactor and GEH BWRX-300
- GEH BWRX-300 will be deeply embedded in a vertical shaft
- Posses some unique issues o Reactor may be in only soil layers, only rock layers, or rock overlain by soil o Rock mass has fractures; joints, bedding planes, faults, cavities (karst features): fracture network o In-situ stress field o Water table From: Cao, et al. 2016. An Experimental and Numerical Study on o Response to Safe Shutdown Mechanical Behavior of Ubiquitous-Joint Brittle Rock-Like Specimens earthquake (SSE) Under Uniaxial Compression. Rock Mechanics and Rock Engineering.
March 18, 2022 GEH BWRX-300 5
GEH BWRX-300 Reactor
- RB is placed in a vertical right-cylinder shaft and located below-grade to mitigate effects of possible external events, including aircraft crashes, adverse weather, flooding, fires, and earthquakes LTR Figure 1-3 March 18, 2022 GEH BWRX-300 6
Regulatory Bases
- Defining Subsurface Conditions o 10 CFR 100.20(c)(1): the Commission consider physical characteristics of the site o 10 CFR 100.23: sets forth the principal geologic and seismic considerations that guide the Commission in its evaluation of the suitability of a proposed site and adequacy of the design bases established in consideration of the geologic and seismic characteristics of the proposed site, such that, there is a reasonable assurance that a nuclear power plant can be constructed and operated at the proposed site without undue risk to the health and safety of the public
- Development of Site Design Parameters o 10 CFR Part 50, Appendix A, General Design Criteria 2: Design bases for protection against natural phenomena March 18, 2022 GEH BWRX-300 7
NRC Staff Review
- LTR proposes approaches at conceptual level to deal with technical issues
- Rock fracture network (LTR Section 3.1.3 and others)
- Stability of reactor shaft (LTR Section 5.1.2 and others)
- Foundation Interface Analysis (FIA) model (including parameter estimation) (LTR Section 4)
- Soil-Structure Interaction (SSI) modeling (including parameter estimation of equivalent linear elastic materials) (LTR Section 5.1.2)
- Strain-compatible dynamic properties (LTR Section 5.2.4)
- Nonlinear SSI analysis (sensitivity) (LTR Section 5.3.11)
March 18, 2022 GEH BWRX-300 8
Other Reviewed Topics in LTR
- Design Earth Pressure Load Validation (LTR Section 5.1.3) including Probabilistic Earth Pressure Analyses (LTR Section 5.1.4)
- Development of Ground Motion Acceleration Time Histories (LTR Section 5.2.3)
- Effects of Non-Vertically Propagating Seismic Waves (LTR Section 5.3.3)
- Approaches for Meeting DC/COL ISG-017 Guidance (LTR Section 5.3.4)
- Modeling of Structure-Soil-Structure Interaction Effects (LTR Section 5.3.7)
- Soil Separation Effects (LTR Section 5.3.9)
- Groundwater Variation Effects (LTR Section 5.3.10)
- II/I interaction effects (LTR Section 6)
March 18, 2022 GEH BWRX-300 9
NRC Staff Review Strategy
- Staff review emphasized on
- Whether the proposed approach is appropriate?
- Has the proposed approach been used before in similar circumstances elsewhere, especially in nuclear applications?
- Has proposed approach any limitations?
- Have all parameter values necessary to use the approach be determined using appropriate test method(s)?
- Does the proposed approach have any inherent assumption that needs to be verified?
March 18, 2022 GEH BWRX-300 10
Rock Fracture Network
- Fractures control the response of a rock mass
- Fracture network:
- Dip angle
- Dip direction
- Fracture spacing
- Number of fracture sets
- Staff will review rock fracture network characterization (LTR Section 3) in a site- From: Cao, et al. 2016. An Experimental and Numerical Study specific license on Mechanical Behavior of Ubiquitous-Joint Brittle Rock-Like application Specimens Under Uniaxial Compression. Rock mechanics and Rock Engineering.
March 18, 2022 GEH BWRX-300 11
Foundation Interface Analysis (FIA) Model (LTR Section 4)
- Response of the interface in normal (perpendicular) direction
- Response of the interface in shear (along) direction
- Shear strength of the interface
- Normal strength = 0
- Model will have rock/soil-structure, rock-rock (joints, bedding planes, etc.), rock-soil interfaces LTR Figure 4-2
- Simulation at different stages: pre-excavation through start-up and operation March 18, 2022 GEH BWRX-300 12
FIA Model Parameter Estimation
- Direct Shear Test in
- Sample rock joint Laboratory surface
- Natural rock joint samples collected in site investigation
- Large sample size From: Fan, et al. 2019. Geotechnical and Geological Engineering. Experimental and Numerical Study on the Damage Evolution of Random Rock Joint Surface During Direct Shear Under CNL Condition.
March 18, 2022 GEH BWRX-300 13
Direct Shear Test of Rock Joint
- Shear Test vs. Shear
- Normal Displacement Displacement vs. Shear Displacement From: NUREG/CR-6178 March 18, 2022 GEH BWRX-300 14
Limitation & Condition (L&C) #1: Interface Characteristics Testing
- Large size samples collected at a site should be tested in the laboratory to have an acceptable estimate of the measured fracture (e.g., rock-rock, rock-soil) and interface (e.g., rock/soil-structure) strength and deformation parameters for a nuclear power plant (Response to RAI 02.05.04-2)
- Staff will review the sizes of the samples and their testing at the laboratory to estimate the properties of the discontinuities and interfaces in a site-specific license application with a BWRX-300 SMR March 18, 2022 GEH BWRX-300 15
Stability of Reactor Shaft
- Stability of Embedded Reactor: Unstable rock mass without any permanent support systems is not acceptable
- Unstable blocks in surrounding region o Key block theory (Goodman and Shi, 1985) o Numerical simulation e.g.,
FIA model (LTR Section 4.0) o Results verified by instrumentation installed From: Cao, et al. 2016. An Experimental and Numerical Study on Mechanical Behavior of Ubiquitous-Joint (LTR Section 3.3) Brittle Rock-Like Specimens Under Uniaxial Compression. Rock Mechanics and Rock Engineering.
March 18, 2022 GEH BWRX-300 16
L&C #2: Stable Excavation
- A stable shaft excavation would have no unstable blocks in its surrounding that may slide into the excavation
- A self-supported (even with some temporary reinforcement) excavation would be needed to place the RB and to estimate the earth pressure loads to be considered in the generic design of the RB structure
- Staff will review method(s) used to identify the unstable rock blocks and to assess the earth pressure imparted on the RB shaft for determining whether the subgrade is acceptable for siting the reactor in a site-specific application
- Any temporary reinforcement or mitigation measures used to stabilize the surrounding materials would be reviewed by the staff March 18, 2022 GEH BWRX-300 17
Soil-Structure Interaction (SSI)
Modeling
- Interaction of embedded RB structure with surrounding media important for integrity of the RB structure
- Simplified assumptions to enable efficient calculation of stress demand on the RB using the System for Analysis of Soil-Structure Interaction (SASSI) computer code o Subgrade material continuous o Subgrade material isotropic and linear elastic o No nonlinearities at soil-structure interface o Static lateral pressure from weight of self-supported rock neglected (Stable Excavation)
- SSI Analysis: following ASCE/SEI 4-16 March 18, 2022 GEH BWRX-300 18
Isotropic, Linear Elastic, Continuous Subgrade Media
- Soil: Elastic modulus Est from Cone Penetration Test (CPT),
Standard Penetration Test (SPT), Pressuremeter
- Rock: Est function of Intact Rock Modulus, Rock Fracture Network, other properties
- Rock Mass Classification Schemes: Rock Mass Rating (RMR),
Geological Strength Index (GSI), others
- Each incorporates rock fracture information
- Groups different rock masses into a few classes
- Experience from past projects used to assign properties of each class
- Empirical correlation with rock mass modulus (or, stiffness) Est
- Rock mass idealized as an isotropic medium March 18, 2022 GEH BWRX-300 19
L&C #3: Isotropic and Homogeneous Rock Mass
- Rock mass classification systems inherently assume isotropic and homogeneous rock mass
- A jointed (or a fractured) rock mass is assumed to contain a sufficient number of fracture sets so that its deformational behavior may be assumed to be isotropic and homogeneous
- Staff will review whether the fracture sets at the selected site would make the rock mass behavior isotropic and homogeneous in any future site-specific licensing application March 18, 2022 GEH BWRX-300 20
Strain-Compatible Subgrade Dynamic Properties
- Properties used as input for SSI analysis to be consistent with soil/rock properties used in generation of input motion
- RG 1.208 and NUREG/CR-6728 o Control motions based on a generic rock site may not result in strain-compatible properties
- GEH has proposed an approach to develop Hazard Consistent Strain-Compatible Properties (HCSCP) consistent with observed strong ground motion parameters
- Assumed strain-compatible properties approximately lognormally distributed, consistent with observed strong ground motion parameters March 18, 2022 GEH BWRX-300 21
L&C # 4: Site Specific Application of the HCSCP
- Approach is reasonable
- It will be the first ever application to a nuclear reactor project
- During review of future licensing applications, staff will audit the HCSCP approach March 18, 2022 GEH BWRX-300 22
Nonlinear Soil-Structure Interaction (SSI) Analysis
- Nonlinear Seismic Soil-Structure Interaction Analysis (LTR Section 5.3.11)
- May be important for sites with high seismicity and/or with highly nonlinear subgrade materials
- Separation and/or sliding at soil-structure interface
- Nonlinearity at rock fractures
- Sensitivity Nonlinear SSI analysis following ASCE/SEI 4-16, Appendix B
L&C # 5: Nonlinear SSI Analysis
- NRC staff plans to review the characterization and modeling of the nonlinear behavior of the materials surrounding the reactor in any future licensing application utilizing a nonlinear SSI analysis approach March 18, 2022 GEH BWRX-300 24
Staff Conclusions
- Staff finds that the approaches proposed to characterize the surrounding media (soil and/or rock) reasonable
- Staff finds that the approaches proposed to develop site design parameters reasonable
- Staff placed five Limitations & Conditions to have a more in-depth review the background information, relevant design/site information, characterization of the surrounding media, and development of site design parameters associated with them March 18, 2022 GEH BWRX-300 25