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