ML22034A982
| ML22034A982 | |
| Person / Time | |
|---|---|
| Issue date: | 01/19/2022 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| Snodderly, M, ACRS | |
| References | |
| NRC-1810 | |
| Download: ML22034A982 (119) | |
Text
Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION
Title:
Advisory Committee on Reactor Safeguards NuScale Subcommittee Meeting Docket Number:
(n/a)
Location:
teleconference Date:
Wednesday, January 19, 2022 Work Order No.:
NRC-1810 Pages 1-71 NEAL R. GROSS AND CO., INC.
Court Reporters and Transcribers 1323 Rhode Island Avenue, N.W.
Washington, D.C. 20005 (202) 234-4433
NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 www.nealrgross.com 1
1 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 NUSCALE SUBCOMMITTEE 7
+ + + + +
8 WEDNESDAY 9
JANUARY 19, 2022 10
+ + + + +
11 The Subcommittee met via Video 12 Teleconference, at 2:00 p.m. EST, Walt Kirchner, 13 Subcommittee Chairman, presiding.
14 COMMITTEE MEMBERS:
15 WALTER L. KIRCHNER, Chairman 16 VICKI BIER, Member 17 RONALD G. BALLINGER, Member 18 CHARLES H. BROWN, JR. Member 19 VESNA B. DIMITRIJEVIC, Member 20 GREGORY H. HALNON, Member 21 JOSE MARCH-LEUBA, Member 22 DAVID A. PETTI, Member 23 JOY L. REMPE, Member 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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2 ACRS CONSULTANT:
1 DENNIS BLEY 2
DESIGNATED FEDERAL OFFICIAL:
ALSO PRESENT:
6 JOSEPH COLACCINO, NRR 7
MICHAEL DUDEK, NRR 8
OMER ERBAY, NuScale 9
LIZ ENGLISH, NuScale 10 GIULIO LEON FLORES, NuScale 11 AMITAVA GHOSH, NRR 12 ATA ISTAR, NRR 13 FEHMIDA MESANIA, NuScale 14 DEMETRIUS MURRAY, NRR 15 RIM NAYAL, NuScale 16 BOB PETTIS, NRR 17 GETACHEW TESFAYE, NRR 18 EVREN ULKU, NuScale 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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3 CONTENTS 1
Page 2
I. Opening Remarks 3
Walt Kirchner...............
4 4
II. Discussion of NuScale Topical Report 5
Fehmida Mesania..............
7 6
Evren Ulku
................ 10 7
III. Staff's Evaluation of NuScale's Topical Report 8
............. 26 9
Ata Istar................. 31 10 IV. Opportunity for Public Comment
....... 69 11 Adjourned.................... 71 12 13 14 15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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4 P-R-O-C-E-E-D-I-N-G-S 1
2:00 p.m.
2 CHAIRMAN KIRCHNER: Okay, good afternoon, 3
everyone. This meeting will now come to order. This 4
is a meeting of the Advisory Committee on Reactor 5
Safeguards, NuScale subcommittee meeting.
6 I am Walt Kirchner, Chair of this 7
meeting. Assisting me, and joining me, is Ron 8
Ballinger, from the Committee.
9 Members in attendance today are, in 10 addition to Ron Ballinger, Vicki Bier, Charles Brown, 11 Greg Halnon, Jose March-Leuba, David Petti, Joy Rempe.
12 And consultants Dennis Bley and Stephen Schultz.
13 Have I missed anyone from the Committee?
14 Please speak up if I have. Hearing none, okay, I'll 15 proceed.
16 Mike Snodderly is the designated federal 17 official for this meeting. The Subcommittee will 18 review the Staff's evaluation of NuScale's licensing 19 topical report, TR-0920-71621, building design and 20 analysis methodology for safety-related structures.
21 Today we have members of the NRC Staff and NuScale 22 Power to brief the Subcommittee.
23 The ACRS was established by statute and is 24 governed by the Federal Advisory Committee Act, FACA.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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5 The NRC implements FACA in accordance with its 1
regulations found in Title 10 of the Code of Federal 2
Regulations, Part 7.
3 The Committee can only speak through its 4
published letter reports. We hold meetings to gather 5
information and perform proprietary work that will 6
support our deliberations at a full committee meeting.
7 The rules for participation in all ACRS 8
meeting were announced in the Federal Register on June 9
13th, 2019. The ACRS section of the U.S. NRC public 10 website provides our charter, bylaws, agendas, letter 11 reports and full transcripts of all full and 12 subcommittee meetings. Including slides presented 13 therein. The agenda for this meeting was posted 14 there.
15 Portions of this meeting can be closed, as 16 needed, to protect proprietary information pursuant to 17 5 U.S.C. 552(b)(c)(4). As stated in the federal 18 register notice and in the public meeting notice 19 posted to the website, members of the public who 20 desire to provide written or oral input to this 21 subcommittee may do so, and should contact the 22 designated federal official five days prior to the 23 meeting, as practicable.
24 A phone bridge line has been open to allow 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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6 members of the public to listen in on the 1
presentations and Committee discussion. We have 2
received no written comments or requests to make oral 3
statements from the members of the public regarding 4
today's meeting.
5 There will be an opportunity for public 6
comment. And we have set aside 15 minutes, in the 7
agenda, for comments from members of the public 8
attending or listening to our meetings.
9 Written comments may also be forwarded to 10 Mike Snodderly, the designated federal official.
11 A transcript of the open portions of the 12 meeting is being kept. And it is requested that 13 speakers identify themselves and speak with sufficient 14 clarity and volume so that they can be readily heard.
15 Additionally, participants should mute themselves when 16 not speaking.
17 So let me reiterate that request. Please 18 mute your phone or your computer when not speaking.
19 We'll now proceed with the meeting. And 20 I will call first upon, do we have any NRC senior 21 Staff who wish to make an introduction?
22 If not, we'll go directly then to the 23 NuScale presentations. And we will begin with Fehmida 24 Mesania from NuScale. Please proceed.
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7 DR. MESANIA: Thank you very much. This 1
is Fehmida Mesania from NuScale licensing engineer.
2 Good morning and good afternoon to everyone.
3 On behalf of NuScale we would like to 4
thank the Staff and the ACRS Committee for the 5
opportunity to present our topical report on the 6
building design and analysis methodology for safety-7 related structures.
8 Can everyone hear me okay?
9 CHAIRMAN KIRCHNER: Yes, Fehmida, that's 10 excellent.
11 DR. MESANIA: Thank you. Liz, please next 12 one. Thank you. My name, like I said, Fehmida 13 Mesania, I'm a licensing engineer with NuScale. Along 14 with my colleagues, we will present our topical 15 report.
16 For this open session it -- are going to 17 be myself and Evren Ulku who will be presenting a 18 generic overview of the content of our topical report.
19 Next slide please. The proposed agenda 20 for today's presentation will include a brief 21 discussion of the process, and introduction of the 22 timeline of events, followed by a technical generic 23 discussion of the building design of the SC walls, 24 reinforced concrete members, in-structure response 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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8 spectra and effective stiffness modeling approach.
1 Next please. So the purpose of this 2
presentation is to present the ACRS a technical 3
content of our topical reports as outlined in the 4
proposed agenda. And also provide a generic 5
understanding of the building design and analysis 6
methodology for the SC-1 and SC-2 safety related 7
structures for the reinforced concrete and steel 8
composite walls that are applicable for the NuScale 9
SMR design.
10 Next slide please. So this slide provides 11 a generic introduction of the timeline of the events 12 moving out to today's meeting.
13 NuScale submitted a topical report on 14 December 2020. NRC accepted for review and completed 15 the audit. And REI, their review by October 2021.
16 So the plant specific did revise our 17 topical report and submitted it as 1. And in November 18 2021 NRC issued its draft SER of the topical report.
19 Next please. Next slide please, Liz.
20 MS. ENGLISH: Are we on Slide 6?
21 DR. MESANIA: Yes.
22 MS. ENGLISH: Okay.
23 DR. MESANIA: Now we can move to Slide 7 24 please. Sorry.
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9 MS. ENGLISH: Oh, okay. Got it.
1 DR. MESANIA: Okay, I think we are missing 2
one. Maybe not. Would you mind going back to --
3 CHAIRMAN KIRCHNER: Fehmida, I think you 4
need to go back to Number 6.
5 DR. MESANIA: Yes. Sorry, Liz. I'm 6
looking at a different screen here. My apologies to 7
everyone. So yes, I did miss a slide so sorry about 8
that.
9 So yes, this slide where we want to just 10 give an introduction of what the content of the 11 topical report is. So the new reactor design recently 12 have adopted a modular steel plate composite structure 13 as one of the design features of the safety related 14 structures.
15 Our report offers an advance building 16 design and analyses methodology that will be used for 17 our SC-1 and SC-2 structures. Our report defines the 18 methodologies to account for the interaction of SC 19 walls with traditionally constructed and reinforced 20 concrete members, such as basemats, slabs and roofs.
21 In addition, this report implements the 22 soil library methodology, as outlined in this topical 23 report. And the information provided in this topical 24 report would be used as part of our standard design 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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10 approval application.
1 Are there any questions or comments so 2
far?
3 MEMBER BROWN: Yes, we were really on 4
Slide 6 so I'm not sure, this is Slide 7 that's 5
showing, are we still behind the eight ball, Walt?
6 DR. MESANIA: We are currently on Slide 6.
7 Are you able to see Slide 6?
8 MEMBER BROWN: Slide 7 is shown on the 9
screen, that's why I asked the question. I don't know 10 what anybody else is seeing.
11 CHAIRMAN KIRCHNER: We are seeing 6, 12 Charlie.
13 MEMBER BROWN: All right, I'm happy. As 14 long as, it's my laptop then. Sorry about that.
15 CHAIRMAN KIRCHNER: Okay.
16 DR. MESANIA: So, if there are no 17 questions so far, I'm going to hand it over to Evren 18 to present a generic overview of the technical content 19 of the report.
20 DR. ULKU: So, thanks for that. Can 21 everyone hear me okay?
22 CHAIRMAN KIRCHNER: Yes, Evren. Go ahead 23 please.
24 DR. ULKU: Okay, thank you. Yes. Good 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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11 morning and good afternoon, everyone. Again, this is 1
Evren Ulku.
2 I am the supervisor for the structural 3
analysis at NuScale Power. I've been at NuScale for 4
about four years now, and almost 13 years in the 5
nuclear industry.
6 So the open session of the presentation 7
today was intended to be a generic introduction for 8
the closed session. I only do have about five slides 9
to cover. And the order of slides we'll cover, is 10 what you will see in the closed session.
11 So I do have two slides for SC walls, one 12 slide for reinforced concrete and ISRS and design 13 methodology and effective stiffness.
14 Please, if you can go to the next slide we 15 can get started. Okay.
16 So in this first slide you see a cross-17 section of SC wall. And SC stands for steel-plate 18 composite. And in this type of construction the 19 concrete it sandwiched between two steel face plates.
20 Reinforcement, or rebar in other words, like what we 21 should see in reinforced concrete, is replaced by the 22 steel face plates.
23 Again, reinforced concrete construction, 24 heavier rebar density reinforce concrete members may 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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12 bring some construction challenges due to congestion 1
and crash of interfacing structural components. So 2
these steel faceplates eliminate that. And they also 3
replace the form work that would be used in 4
traditional reinforce concrete construction.
5 We do have steel anchors, or referred to 6
as steel-headed stud anchors, in the figure. Okay, 7
was there a question from someone? Okay.
8 CHAIRMAN KIRCHNER: Please proceed.
9 DR. ULKU: Okay. So we do have stud 10 anchors and they ensure composite behavior within the 11 faceplates and the concrete.
12 There are tie bars between two faceplates.
13 And sometimes there are tie plates. They promote 14 structural integrity, they prevent the elimination of 15 concrete.
And
- finally, they serve as huge 16 reinforcement when the design is complete.
17 You can see in the figure --
18 DR. BLEY: How does it work then for 19 delamination? Just by keeping pressure on it?
20 DR. ULKU: Yes. And then, let's see, you 21 see like for penetrations, again, in the figure, they 22 can be, again, introduced in the design stages, or 23 sometimes during construction stages. But again, they 24 bring in the same advantages before the models are 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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13 built.
1 Again, the embedded plates, they are in 2
the, for commodity attachments. An additional 3
commodity attachments can be introduced during 4
construction. Or even during service, if there is a 5
need.
6 Liz, if we can go to the next slide.
7 Okay. And this slide is, again, SC wall related. We 8
are looking now at potential advantages and 9
disadvantages, or I would call maybe where we need to 10 pay closer attention.
11 Again, the first bullet talks about the 12 higher resistance against, like some of the design 13 basis, blast or earthquakes. We do have higher 14 ultimate strength with SC walls that comes in with the 15 steel faceplates, which like provides significant 16 contribution to that.
17 And as you see, there are considerable 18 reduction in fabrication and erection times that is 19 inherent with the module construction itself. This 20 provides improvement in the wall construction 21 schedule. And that translates like savings in the 22 wall plant cost.
23 The module, whereas we plan to use, and we 24 do have some figures in the closed session. They are 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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14 smaller and lighter than previously used designs. And 1
they are intended to be easy to transportable on the 2
bed of a semi-truck. So we do have like weight and 3
size restrictions on them that we are working on 4
currently.
5 Now, the area is where we need to pay 6
extra attention, or special attention. Again, the 7
first is the connection reasons.
8 The connections, like anywhere between SC 9
wall panels, like that might be horizontal where it 10 joins. And like RC elements, reinforced concrete 11 elements with the floors, basemats and the roofs.
12 Like they may require some extra attention.
13 Again, these are potential areas where 14 congestion or like where we need to develop the 15 components.
16 DR. BLEY: Let me interrupt --
17 DR. ULKU: Another area --
18 DR. BLEY: -- again.
19 DR. ULKU: Sure.
20 DR. BLEY: It's Dennis Bley. A few years 21 back another applicant came in using this approach.
22 At that time the consensus standard was not in place 23 for this kind of construction. There were some issues 24 raised.
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15 But can you give us a little background on 1
the history of this approach and what's the longest, 2
you know, application that's been in place? And not 3
necessarily in the nuclear business but elsewhere.
4 DR. ULKU: So, let me rephrase the 5
question. So again, there was another vendor and then 6
at the time they had not, or there did not appear to 7
be a standard for this type of construction. Was your 8
question related, like, are you asking about --
9 DR. BLEY: Now, that was a statement.
10 DR. ULKU: -- developments or --
11 DR. BLEY: That was a statement.
12 DR. ULKU: Okay.
13 DR. BLEY: That at that time there was not 14 a standard.
15 DR. ULKU: Okay.
16 DR. BLEY: The question is, what's the 17 history of this kind of this construction throughout 18 the world and what's the longest, the oldest example 19 that's still a standard, that you know of?
20 DR. ULKU: I see. I think, yes, let me 21 see. It did start in, I think, maybe Japan and those 22 part of the world. And I think it goes back to maybe 23
'80s or '90s.
24 And it started with commercial 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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16 construction. And we did have like some other 1
composite members or, not necessarily fuels, but 2
again, say concrete and fuel, fuel members. Like in 3
hybrid construction I would call, in like different 4
parts of the world that using it for tall buildings 5
and whatnot.
6 And obviously, like for nuclear 7
construction, again, like another vendor, like people 8
that have, like, they started it and that wasn't a 9
standard at the time. They used like other concrete 10 cores, and whatnot, to come up with their own 11 methodology and criteria documents to do that.
12 But in U.S., at least more recently, for 13 example, that we were building like the tower that was 14 built a few years ago that provided like significant 15 cost savings and like construction schedule savings.
16 That spot we build
- this, again, commercial 17 construction, but again, it's standing a couple 18 hundred feet tall.
19 DR. BLEY: Okay, but that's fairly recent.
20 But you say this has been used in building 21 construction as much as 30 years ago in Japan, is that 22 correct?
23 DR. ULKU: Right.
24 DR. BLEY: Okay, thank you.
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17 DR. ULKU: That is my thought. Yes.
1 MEMBER REMPE: Dennis, if I could ask for 2
some clarification to the answer or are you done?
3 DR. BLEY: I'm done.
4 MEMBER REMPE: You mentioned it was for 5
hybrid construction. What do you mean by that term?
6 I'm sorry, I'm not an expert in this area.
7 DR. ULKU: When I said hybrid, for 8
example, I meant that say, for example, you build a 9
traditional or reinforced concrete buildings, that it 10 may have some core elements, let's say. And then 11 there was some members may have steel faceplates and 12 they may have concrete in it.
13 So, it's not necessarily the same thing we 14 talk today, but it is similar in the sense that it was 15 built. And those are even like earlier than 30 years 16 ago.
17 MEMBER REMPE: Okay, thank you.
18 CHAIRMAN KIRCHNER: I think Ron Ballinger, 19 I think you had your hand up?
20 MEMBER BALLINGER: Yes. I would remind 21 the members that we reviewed Reg Guide 1.243, or we 22 had a chance to, and we decided not to, in August.
23 And that document endorses the various codes and 24 standards, N690-18 and AISC-360 something or other, I 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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18 forget the exact details, which endorsed the use of 1
these composite walls.
2 So we had a chance to, we looked at this 3
in that Reg Guide, and its references are very 4
extensive. And would provide members with the history 5
and all kinds of information if they need to go and 6
get it.
7 DR. BLEY: We didn't look at it, from what 8
you said. What was the Reg Guide number, Ron?
9 MEMBER BALLINGER: 1.243.
10 DR. BLEY: Thank you.
11 DR. ULKU: Okay. And the last bullet on 12 this part of the slide is, again, the issue of 13 corrosion effects.
14 We did intend to use the SC walls below 15 grade. And we do have, I think in additional slides 16 on this one in the closed session, so we'll come back 17 to this in the closed session a little bit more.
18 Liz, if we can go to the next slide. Now, 19 this is on reinforced concrete. Again, even the SC 20 walls introduce quite a few advantages over reinforced 21 concrete. We are not trying to abandon reinforced 22 concrete altogether. And we'll use reinforced 23 concrete where it proves to be advantages.
24 For example, members in part, floor slabs, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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19 roof, basemats. They are pretty much all reinforced 1
concrete. And again, this is believed to be 2
advantages during construction.
3 And we plan to use, again, the latest 4
addition of the nuclear code ACI 349 for reinforced 5
concrete members.
6 Can you go to the next one? Yes. And 7
this is like why we will present the, like how you 8
extract the in-structure response spectra, ISRS. And 9
for some models for the member design.
10 And this section we can deem as an add-on 11 to our previous topical report on the -- like the 12 analysis. So we do have like, again, detailed slides 13 on how we are choosing some values, the building 14 analysis and design.
15 And prior to, sort of methodology, we 16 present, are consistent with the latest industry codes 17 and standards.
18 Like here you see two criteria documents 19 from ASCE on building analysis and design for nuclear 20 structures. And one is the concrete code and the 21 other one is the steel code for nuclear construction.
22 To go to the final slide, Liz. On 23 effective stiffness. Okay.
24 So again, we'll go into quite a bit of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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20 details on, like what we are doing for stiffness. So 1
in this slide, this slide can define generically, like 2
what is stiffness versus what is effective stiffness.
3 So stiffness, again, in simplest terms, is 4
the resistance of deflection extent to which an object 5
resists the formation, say, in response to an applied 6
force.
7 And for structural wall members, again, 8
like from geometric properties, geometric properties 9
are the basic things that the stiffness depends on.
10 But it also is dependent on like a lot of other 11 factors. Say the reinforcement ratio, rebar from the 12 foundation, the foundation rotation, the exit portion, 13 the wall. It's a complex phenomena.
14 Concrete, again, on the other hand, is a 15 non-linear material and it is going crack on the 16 design loads. And we show like different cracking on 17 the different set of flows like, again, for tension, 18 for shear for example, like we may see different 19 things.
20 And then we see concrete, absorb concrete.
21 That stiffness of the member further changes, it 22 reduces, and it becomes an even more complex phenomena 23 itself.
24 So to make things simple, like when I say 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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21 things I mean design because, again, ASCE or ACI did 1
provide effective stiffness values that we can use.
2 And these are given as a fraction of gross thickness.
3 Say for example, we would use 70 percent 4
of the stiffness for columns and compression versus 50 5
percent of the columns intention for actual thickness.
6 And again, we see different reduction 7
factors for different stiffness. Say for example we 8
use half of the selection when we see cracking, but 9
then we use capacity for shears. So it is different.
10 And we develop some methodologies where we 11 match different significant values for different 12 numbers. Again, like by using orthotropic material 13 properties, using some layered elements and element 14 layers to match the --- so we got quite a bit of 15 details where we can start the slide.
16 And I think that's it on my end. The last 17 slide is just acronyms, Liz. If there are any further 18 questions I'd be happy to answer.
19 CHAIRMAN KIRCHNER: Well, Evren, this is 20 Walt. You know, this is a very complicated topic 21 we're presenting right now to the, in an open session 22 to the general public.
23 Could you explain to the general public 24 why they should not be concerned if one of these 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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22 structural members has cracks?
1 DR. ULKU: Now, again, the reinforced 2
concrete, we designed, we are designing members to the 3
ultimate strength level. And at the ultimate strength 4
level they are expected to crack.
5 So it is nothing to, like be scared of or 6
it is nothing to worry. But we do need to take into 7
account the reduction of stiffness due to crackings.
8 CHAIRMAN KIRCHNER: All right.
9 DR. ULKU: So, we are actually presenting, 10 representing, the true material property by taking 11 into account the effects of cracking.
12 CHAIRMAN KIRCHNER: Well, I would have 13 gone further and said that the codes and standards 14 that you referenced in your TR provide for this, and 15 then provide design margin to compensate for these 16 kinds of things, like cracking of the concrete. Isn't 17 that correct?
18 DR. ULKU: That is correct. Yes.
19 CHAIRMAN KIRCHNER: Yes.
20 DR. ULKU: It is correct. Yes.
21 CHAIRMAN KIRCHNER: Okay.
22 MEMBER BROWN: This is Charlie, can I ask 23 a question?
24 CHAIRMAN KIRCHNER: Go ahead, Charlie.
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23 DR. ULKU: Sure.
1 MEMBER BROWN: Okay. Is this cracking, 2
I'm not a concrete guy either, obviously, in the 3
plants we had today, does the concrete, reinforced 4
concrete container, are they understood to crack also?
5 DR. ULKU: Yes.
6 MEMBER BROWN: Under load? So this is not 7
8 DR. ULKU: Yes.
9 MEMBER BROWN: -- it's not --
10 DR. ULKU: Again --
11 (Simultaneous speaking.)
12 MEMBER BROWN: I'm sorry, go ahead.
13 DR. ULKU: It is not different from the, 14 again, existing plants or the new plants. This 15 concept has been out there, again, for quite a while 16 and has been considered in the, again, the standard 17 review plans.
18 The only thing we are doing is maybe, 19 again, like it is a more medium material but we are 20 still assuming can go linear in the analyses. So by 21 using, again, that red curve you see on the slide, 22 like these are still sent to the linear on the linear 23 aspect space.
24 But this is maybe a better representation 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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24 of the actual state of conditions. But then again, 1
the buildings are tested against the design margins.
2 But again, it is nothing new. It has been 3
out there for quite a while. And, again, it includes 4
the plant, existing plants.
5 MEMBER BROWN: Okay, thank you.
6 MEMBER BALLINGER: This is Ron Ballinger 7
again. The steel plate composite walls have been used 8
in the past for nuclear construction as well, am I 9
right?
10 Only it has to have been, it had to have 11 been approved on a case-by-case basis before 1.243 got 12 updated.
13 DR. ULKU: Right. So, it is true, yes.
14 Again, it was used on a case-by-case basis. The 15 Applicant, I guess they used ACI, the concrete codes.
16 And they changed, again, some aspects of the code or 17 had to come up with their own approaches and 18 methodologies for the design.
19 But right now, again, Reg Guide 1.243 is 20 out there. The latest code, N690-18, Appendix N9 is 21 out there. So we are making use of the latest and 22 greatest standards.
23 CHAIRMAN KIRCHNER: Ron, this is Walt. If 24 I remember correctly, we have several plants out there 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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25 that use this SC walls for support of the reactor 1
vessel and shield, isn't that correct?
2 MEMBER BALLINGER: Yes, I think that's 3
true. I actually had a list but I can't, I've been 4
feverishly trying to find it in my antiquated filing 5
system. But I haven't been able to.
6 CHAIRMAN KIRCHNER: So I think there is 7
experience, going back to Dennis's question, there is 8
experience in the industry with variations on this 9
steel plate composite, concrete wall construction.
10 DR. BLEY: What I was kind of interested 11 in was the history of it. If you remember, back when 12 we did that other design cert where this came up, 13 there was a very strong and detailed disagreement 14 among the staff that was brought to us and shown to us 15 at that time. But again, that was before there was a 16 standard.
17 Now, as the point Ron raised, we decline 18 to review the Reg Guide 1.243. I kind of think most 19 of us didn't realize that it included the steel wall, 20 steel composite wall issue. And so questions at this 21 time seem appropriate since we never really looked at 22 this in detail after that first application that came 23 in.
24 MEMBER BALLINGER: Well, the review memo 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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26 that was written specifically called out this type of 1
construction.
2 DR. BLEY: Nevertheless, we never really 3
talked it through.
4 MEMBER BALLINGER: Okay, I got it. We can 5
always change our minds and review it.
6 DR. BLEY: I'm just glad to know where it 7
is. And I've started reviewing it already.
8 MEMBER BALLINGER: Well, I sent you a 9
copy.
10 CHAIRMAN KIRCHNER: Okay, Evren, does this 11 complete the NuScale presentation for the open 12 session?
13 DR. ULKU: That is correct. Yes.
14 CHAIRMAN KIRCHNER: Okay. Members, are 15 there further questions at this juncture for NuScale?
16 Hearing none, then we'll turn to the 17 Staff. And I believe that we will hear first from 18 Demetrius Murray from NRR.
19 MR. MURRAY: This is Demetrius Murray with 20 NRR. Can you hear me?
21 CHAIRMAN KIRCHNER: Yes, Demetrius. A 22 little louder please, if you could.
23 MR. MURRAY: Is that better?
24 CHAIRMAN KIRCHNER: That's better.
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27 MR. MURRAY: Okay. Thank you.
1 CHAIRMAN KIRCHNER: Go ahead.
2 MR. MURRAY: Good afternoon. I would like 3
to thank the ACRS Subcommittee, NuScale and the 4
general public for entertaining the NRC for our 5
presentation of the safety evaluation of NuScale 6
rebuild and design and analysis methodology for 7
safety-related structures topical report.
8 In December of 2020 NuScale submitted Rev 9
0 of the building design topical report to the NRC.
10 After acceptance of the topical report the NRC issued 11 multiple requests for additional information to 12 NuScale in May and August of 2021.
13 NuScale provided an answer to the NRC's 14 REIs in June and September of the same year. NuScale 15 issued Rev 1 of the topical report to the NRC on 16 October 6th of 2021.
17 We are here today to discuss the Staff's 18 advance safety evaluation of the topical report. The 19 Staff review was Ata Istar, Dr. Amitava Ghosh and now 20 retired Robert Pettis. I am the topical report 21 project manager, Demetrius Murray, supported by senior 22 project manager Getachew Tesfaye.
23 Before we transition to Ata, I would like 24 to open the floor to NRC management. I would like to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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28 introduce Michael Dudek followed by Joseph Colaccino.
1 MR. DUDEK: Thanks, Demetrius. So on 2
behalf of NRC management, Mr. Kirchner, I would like 3
to thank the Committee for hearing us on this novel 4
topical report that NuScale has proposed to us today.
5 I've listened intently to the NuScale's 6
presentation regarding steel plate composite walls and 7
reinforced concrete walls. And intensely read the 8
SERs from the Staff.
9 And I found it very intriguing, so I'm 10 very looking much forward to the presentation by the 11 Staff today.
12 And thanks to both NuScale for the 13 collaborative and efficient discussions that we've 14 had, whether it's REIs or clarifications on this 15 topic. I think it's been a very effective approach.
16 And thanks to Mr. Colaccino and his staff, 17 Mr. Istar, Ghosh and Pettis for their collaboration 18 and hard work on this SER, I think it really shows.
19 And I'm really looking forward to the presentation 20 today.
21 And now I'll turn it over to Mr. Colaccino 22 for any technical opening discussion that he may have.
23 But thanks to the Committee for hearing us today.
24 MR. COLACCINO: This is Joe Colaccino, I'm 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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29 chief of the civil structure of Geotechnical 1
Engineering Branch. And I thank Mike for that intro, 2
he covered most of the stuff.
3 I would like to recognize Bob Pettis, who 4
did retire last month. He was the lead for this 5
project. I think he greatly supported all the 6
technical decisions that were, that we made in the 7
approximately one year review of this topical report.
8 Ata Istar is going to give the 9
presentation today. Amit is going to be backup with 10 any questions that you may have on his portion of the 11 review.
12 I also want to note that prior to 13 receiving this topical report the technical staff 14 became aware of the efforts and research to endorse 15 the code that you've been discussing. The N690-18 16 code that came up in the comments. I was actually 17 really happy to hear about that.
18 Based on the timing of this application, 19 and research efforts to publish a regulatory guide on 20 this topic, the staff review team, led by Bob, 21 coordinated NRR's review and issuance of the staff 22 safety evaluation with the issuance of the research 23 Reg Guide 1.243.
24 And I'd like to thank, specifically, the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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30 research staff for working with the staff in my 1
branch. And acknowledge the applicant's support of 2
that as well.
3 We asked another set of REIs, that you may 4
have heard that Demetrius said, to understand, making 5
sure that we were actually consistent. That what was 6
presented in the NuScale topical was consistent with 7
what the research staff was in the process of 8
endorsing without actually having that report out.
9 That was kind of like a unique effort our part that I 10 felt.
11 Our coordination led to the staff's SEC 12 reflecting the endorsement of the N690-18 code and 13 ensuring that the information that the Staff was 14 approving in the topical report was consistent with 15 this Reg Guide.
16 I think this effort was kind of unique, 17 and that's why I wanted to highlight it. And I 18 appreciate the ACRS recognizing it. At least looking 19 at that, understanding that they did not look at the, 20 you did not request to look at that topical report.
21 But I do want to acknowledge that the Staff was very 22 aware that was going on and worked our efforts in 23 concert.
24 With that, I'd like to now turn back, turn 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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31 it over to Ata, unless there are any questions.
1 CHAIRMAN KIRCHNER: Thank you, Joe. Let's 2
proceed.
3 MR. ISTAR: Good morning and good 4
afternoon, everyone. This is Ata Istar. I'm the 5
structural engineer. One of the members who have 6
reviewed the topical report.
7 Before I go further I would like to 8
recognize Bob Pettis one more time, that he was the 9
lead for the review. And to the last day of his NRC 10 employment he was contributing to the review of this 11 topical report. He is going to be missed.
12 The agenda for this topical report is as 13 follows. Introductions, regulatory bases, background 14 and NuScale TR presented methodologies for each 15 section, followed by the Staff review and evaluation, 16 limitations and conditions and Staff conclusion.
17 Next slide please. NuScale Topical Report 18 offers design and analysis methodologies to be used in 19 the evaluation of Seismic Category I and II 20 structures, applicable to the new generation of small 21 modular reactors.
22 The Staff review included development of 23 in-structure response spectra and design of structural 24 members, determination of the effective stiffness of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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32 elements in ANSYS models, assessment of steel plate 1
composites, walls and connections, assessment of 2
reinforce concrete structures.
3 The development of in-structure response 4
spectra and the design of structural members and the 5
assessment of SC walls, such as steel plate composite, 6
I'm just abbreviating, I may abbreviate time-to-time, 7
walls and connections, NRC structures, conforms to the 8
engineering principles and the applicable industry 9
codes and standards.
10 The determination of effective stiffness 11 values were performed analogically using the codes and 12 standards to represent the composite members of SC and 13 RC structures, and then was confirmed with the 14 implementation of ANSYS models using solid shale, and 15 shale elements.
16 Next slide please. The regulatory basis 17 that we used during the review are 10 CFR 50, Appendix 18 A, General Design Criteria 2 and 4. And 10 CFR 50, 19 Appendix S.
20 Next slide please. The guidance document 21 that we used during the review are Reg Guide 1.243, 22 which this particular, and recently, should, Reg 23 Guide, endorses the N690-18 code, AISC N690-18 code, 24 Reg Guide 1.142, Reg Guide 1.199, Reg Guide 1.61 and 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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33 Reg Guide 1.122.
1 Next slide please. Section 3.7.2 and 2
Section 3.8.4 of NuScale design specific review 3
standards were also used during the review.
4 Next slide please. The code standards 5
that we used are two AIC codes, two ACI codes and two 6
ASCE codes.
7 They're like N690-18, which I stated 8
earlier, which was endorsed by, recently issued Reg 9
Guide 1.243. And AISC 360-16, ACI 349-13, ACI 318-08, 10 ASCE 43-19, ASCE 4-16.
11 Next slide please. The NuScale TR 12 presents a methodology for the design of analysis of 13 seismic Category I and II structures. In the TR, 14 Section 4.0, the development of in-structure response 15 spectra and the design of structural members.
16 In Section 5.0 of the TR the determination 17 of effective stiffness of members. In Section 6.0 and 18 7.0 of the TR, the assessment of steel plate composite 19 walls and connections. And Section 8.0 of the TR, 20 assessment of reinforcement concrete of the 21 structures.
22 The TR also described the use of computer 23 software codes, ANSYS, in determination of effective 24 stiffness values. ANSYS is the general purpose 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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34 commercial available finite element computer code that 1
has been accepted by the engineering committee and 2
used in the right of structural applications.
3 Including linear and nonlinear static and dynamic 4
analysis.
5 The Staff concluded that the ANSYS program 6
discussed can be accepted for design and analysis of 7
seismic Category I and II structures without further 8
validation. Therefore the Staff did not review, nor 9
the Applicant, demonstrate the acceptability of ANSYS 10 computer code.
11 Next slide please. The methodology for 12 the design and the analysis of SC wall is providing in 13 AISC N690-18. Again, which was endorsed by Reg Guide 14 1.243.
15 This is the first TR for the staff review 16 related to the design of steel plate composite walls 17 in accordance with Appendix N9.0 AIC, AISC N690-18.
18 The NRR ESB staff also participated in the 19 public comment resolution over the Reg Guide 1.243.
20 NuScale, DSRS, acknowledges in 1994 edition of N690 in 21 Section 3.8.4, but has not been endorsed.
22 Using the provisions from Appendix N9 and 23 commentary in AISC N690-18, the Staff developed a 24 systematic flowchart for guidance providing a
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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35 sequential steps for the design and analysis of SC 1
walls and connections. And the Staff used this 2
flowchart during the review process of the TR.
3 N9, AISC N690 organized as follows. N9.1 4
section is related to design requirements. N9.2, 5
related to the analysis requirements. N9.3, design of 6
SC walls. N9.4, design of wall connections.
7 Next slide please. Section 4 of the TR 8
presents a methodology to obtain the in-structure 9
response spectra and the design of member forces in 10 seismic Category I and II structures.
11 The process includes development of two 12 ANSYS finite element models, seismic and static, 13 representing a small module reactor. The model 14 includes the reactor building, control building, 15 radioactive waste building and surrounded by 16 engineering, engineered backfill.
17 These models are referred as triple 18 building model. And they're abbreviated as TRB. The 19 TRB seismic model is used in conjunction with the soil 20 library methodology presented in NRC approved report, 21 NuScale TR 0118-58005, to determine the in-service 22 response spectra and the member forces from the safety 23 shutdown earthquakes.
24 The TRB model is used to determine the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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36 member forces from seismic demands and in-structure 1
response spectra. The TRB static model is used to 2
determine the forces from non-seismic loads.
3 Different material models from soil 4
library were used. Soil Type 11 represents soft soil 5
profile. Soil Type 7 represents a rock soil profile.
6 Soil Type 9 represents a hard rock soil profile.
7 Five seismic, certified seismic design 8
response spectra is abbreviated CSRDS. Those are 9
Capitola, Chi-Chi, El Centro, Izmit, and Yermo, 10 seismic motions were used with soil Type 7 and 11, 11 soft and rock respectively. And soil Type 9, hard 12 rock, has been evaluated with certified seismic design 13 response spectra with high frequency motion for 14 Lucerne station.
15 Next slide please. Analysis start with 16 the TRB seismic model with structural members having 17 all cracked material properties subject to CSRDS 18 motion.
19 When I say CSRDS, it represents CSRDS and 20 high frequency CSRDS. Just, I'm trying to abbreviate 21 the discussion.
22 The harmonic analysis is represented from 23 each CSRDS motion and for each soil type soft, rock 24 and hard rock. It is expected some members are 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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37 cracked under the ASCE events.
1 An engineering investigation is performed 2
to determined which ones are cracked. Then the 3
stiffness and damping route used. All the cracked RC 4
members where updated to effective stiffness and 5
damping values as provided in ASCE and AIC standards.
6 New analysis using the seismic motions 7
per, are performed with updated effective stiffness 8
values and damping values. The damping values are 9
consistent with the Reg Guide 1.61.
10 Next slide please. Member forces from 11 non-seismic loads are determined from the TRB static 12 model. And combined with the seismic matter forces at 13 each timestamp.
14 In-plane stiffnesses are matched in both 15 static and seismic models. Maximum demand to capacity 16 ratio is determined and reinforcement is added as 17 necessary. Analysis is presented for each soil type 18 with appropriate CSRDS motions.
19 Determination of in-structure response 20 spectra is generated at a given location of a 21 structural member from the harmonic analysis with 22 updated stiffnesses and damping properties. For each 23 of the five CSRDS motion.
24 The peak of the in-structure response 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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38 spectra is brought in by plus or minus 15 percent, 1
followed by Reg Guide 1.122 guidance to account for 2
uncertainties in the structural frequency.
3 The average in-structure response spectra 4
is calculated from the results obtained from each 5
CSRDS motion. In-structure response spectras are 6
enveloped for three soil types and for each seismic 7
motion.
8
- Finally, the in-structure response 9
spectras are enveloped for three soil types. The 10 Staff finds both approaches consistent with the 11 NuScale DSRS Section 3.7.2.
12 Next slide please. Section 5.0 of the TR 13 represents the modeling approaches using effective 14 stiffness values for RC walls and slabs. And SC walls 15 using the ANSYS finite element code.
16 As discussed in Section 4 of the TR, an 17 effective stiffness values are determined using the 18 ASCE 4-16 for RC walls and slabs, AISC N690-18 for SC 19 walls.
20 As shown in the figure, a typical SC wall 21 section comprised of concrete place between faceplates 22 with tie bars and headed stud anchors. I will 23 describe further about this SC wall in the other 24 slides. In the following slides.
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39 And elastic FE model of SC walls in 1
section can be developed per section N9.2.3 of AISC 2
N690-18. The Poisson's ratio to concrete is used if 3
the section thicknesses and elastic models and 4
densities are calibrated.
5 Next slide please. Two alternate methods 6
were used in, to calibrate the effective stiffness and 7
density values. Method 1, one layer system with two 8
dummy layers for both RC and SC walls. Middle layer, 9
effective properties from ASCE 4-16 and AISC N690-18.
10 Method 2, three layer system for SC walls 11 only. Different material properties for middle and 12 outer layers from ASCE 4-16 and AISC N690-18.
13 ANSYS finite element models were, are 14
- modeled, with SOLSH190 and SHELL181 elements.
15 Generally, isotopic materials are used in the analysis 16 of nuclear, at the nuclear industry.
17
- However, in this
- case, orthotropic 18 material properties represent the composite members 19 for the walls and the slabs. Orthotropic materials 20 properties are independently defined along the three 21 orthogonal access.
22 Three Young's moduli, three shear moduli 23 and three Poisson's ratios. Based on the review, the 24 approaches to determine the orthotropic materials are 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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40 acceptable.
1 Next slide please. ANSYS finite element 2
model is a three-dimensional rectangular structure for 3
where we find the implementation of effective 4
stiffness values.
5 TR analysis includes five example problems 6
to validate the use of proposed SOLSH190 and SHELL181 7
elements in the ANSYS model. The ANSYS model with 8
SOLSH190 elements were used in both Methods 1 and 2 9
produced comparable results.
10 Results with SHELL181 element agree with 11 the results of SOLSH190 elements. Although to 12 calculate the frequency with SHELL181 elements are 13 slightly lower.
14 ANSYS model with SOLSH190 represents 15 connection regions better and preferred. Using the 16 provisions from ASCE 4-16 and AISC N690-18, and the 17 staff finds to those you determine the effective 18 stiffness and density values conforms to NuScale DSRS 19 Section 3.7.2 and 3.8.4. And Reg Guide 1.243.
20 Next slide please. In Section 6 of the TR 21 described a design methodology for straight steel 22 plate composite walls based on the requirements of 23 Appendix N9 of AISC N690-18. And the applicable 24 provision in AISC 360-16.
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41 Where AISC N690-18 was recently endorsed, 1
recently issued in endorsing Reg Guide 1, endorsed by 2
3 As shown in Figure A, the typical RC wall 4
composites structure is placed on all concrete between 5
either carbon steel or stainless steel faceplates.
6 Steel anchors assures composite behavior of faceplate 7
and concrete. Ties between the faceplates provides 8
structural integrity, prevents lamination of concrete 9
core and serves as a shear reinforcement.
10 The SC walls can be connected to each 11 other and anchored to the traditional constructed RC 12 basemat, slabs and walls. The design is performed 13 using the load resistant factors design per AISC N690-14 18.
15 The specification include the design 16 requirements for interior, for interior section, 17 interior region per section N9.1 and connection region 18 per section N9.4.
19 Impactive and impulsive loads will be 20 discussed further. Which were also performed, and 21 designed per Section N9.1.6.
22 Analysis for all of the SC walls performed 23 for interior
- regions, per Section N9.2.5 and 24 connection region per Section N9.4.2. Using effective 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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42 thicknesses in the finite element models requires 1
strength in SC walls are determined. Design of SC 2
walls, the available strengths, are determined per 3
section N9.3.
4 Qualification of SC walls are performed 5
based on the comparison of required strength against 6
the available strength. Where the required strength 7
has to be less than or equal to available strength.
8 And the corrosion effect will be discussed 9
a little, right after this.
10 CHAIRMAN KIRCHNER: So, Istar, this --
11 MR. ISTAR: Yes.
12 CHAIRMAN KIRCHNER: -- is Walt Kirchner.
13 MR. ISTAR: Yes, sir.
14 CHAIRMAN KIRCHNER: This is a nice 15 illustration in that field. And my experience in the 16 field is a little different.
17 So you show an embedded plate for 18 commodity attachments. Whether, it could be for pipe 19 hangers, whatever.
20 What happens in the field if that wasn't 21 designed and accounted for initially?
22 What I'm thinking of is, you're in the 23 field and now you've already poured concrete, we had 24 a question earlier about delamination. So you've 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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43 already poured concrete and now you're welding on a 1
plate that you're going to attach something to.
2 Does that have to be analyzed in the 3
field?
4 MR. ISTAR: Yes. It's an additional load 5
to the structure. But I don't think the intent of the 6
SC walls to weld additional supports to support other 7
structures. These are like exterior walls that is 8
going to be placed for the reactor building, mostly.
9 And of course, if the applicant were to 10 weld the support off of the faceplates, that needs to 11 be accounted for. Because that's a localized --
12 CHAIRMAN KIRCHNER: Right.
13 MR. ISTAR: -- condition for that 14 situation.
15 And in the design of SC equations 16 associated with the buckling of those faceplates --
17 CHAIRMAN KIRCHNER: Yes.
18 MR. ISTAR: -- there's a lot of, a lot of 19 thinking goes into that. And I don't believe in 20 anyone who is using the SC walls would consider 21 supporting anything without the analysis originally 22 performed on this. Deviations will be very difficult 23 to do.
24 CHAIRMAN KIRCHNER: Well the ideal world 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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44 this would be designed and accounted for, and we'll 1
hear from NuScale. (Audio interference.) It might be 2
welded on in a shop somewhere and all that would be 3
accounted for.
4 But in the real construction world, as you 5
know, often the pipe sleeve that is shown in this 6
picture or the plate is not really in any of those and 7
its alterations. Just --
8 MR. ISTAR: It -- yes, go ahead.
9 CHAIRMAN KIRCHNER: Are you assuming that 10 we'll have an immaculate design that doesn't require 11 any in-fields modifications and such?
12 I am just testing you to see what would 13 happen in practice in the fields.
14 MR. ISTAR: Yes. I -- let me go back to 15 whenever your statement was associated with the shop 16 building.
17 I think Ulku in an earlier presentation he 18 meant the SC walls and the anchors and tie bars and 19 everything can be constructed and fabricated in a shop 20 in smaller scales and they can be brought up to the 21 site and placed and then the concrete will be poured.
22 That's what he meant. I don't think he meant that --
23 (Simultaneous speaking.)
24 CHAIRMAN KIRCHNER: Well that's the ideal 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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45 world.
1 MR. ISTAR: Yes.
2 CHAIRMAN KIRCHNER: Yes. That it's 3
prefabricated and your design, that pipe sleeve is 4
perfectly located until it --
5 MR. ISTAR: Yes.
6 CHAIRMAN KIRCHNER: Unfortunately, you 7
install all the equipment and find out it's not where 8
you need it and then you are into a mod, some kind of 9
mod in the field.
10 MR. ISTAR: Yes. I mean these are again 11 small modular reactors. I mean if you are to taking 12 a big AP1000 shield wall kind of situation it's a big, 13 very big structure, and these are much, much smaller 14 than what those full scale reactor, I should say 15 shield walls, and these are reactor building walls.
16 I think the --
17 CHAIRMAN KIRCHNER: Well, the RXB, the RXB 18 is a huge construction project. I can see how they 19 could -- maybe in the closed session we can explore 20 this further. I am very interested in connections.
21 MR. ISTAR: Yes.
22 CHAIRMAN KIRCHNER: But for something as 23 large as the RXB if they are using steel plate 24 concrete walls then these are going to be sections 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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46 that are going to be connected, you're talking about 1
a very large structure if they completed RXB.
2 MR. ISTAR: Yes. It's -- I mean it's not 3
as large as the one that, as AP1000 I would think, you 4
know. I forget the dimensions, but it's not as large, 5
but it is large.
6 I mean these are for small modular 7
reactors and it's, you know, it is -- I think if it's 8
engineered properly everything should work 9
accordingly, you know.
10 There is going to be a lot of thinking in 11 how to do everything sequentially and for the 12 connections and everything. It is -- it may get 13 complicated, I agree with you.
14 It may get complicated with the use which 15 side, you know, as I told earlier, it could be 16 stainless steel or carbon steel.
17 Stainless steel may be used in some 18 instance where the pool is and those things may need 19 to be considered in depth.
20 CHAIRMAN KIRCHNER: Well I'll just assert 21 now, and we can go into more detail in the closed 22 session --
23 MR. ISTAR: I think so.
24 CHAIRMAN KIRCHNER: -- but I think the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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47 RXB, the RXB is so big that it's not, it's going to 1
have to be sections that are prefabricated.
2 The actual walls, if they are going to use 3
this for any of the pool walls, are going to be much 4
larger than you can move on a truck.
5 MR. ISTAR: Well I think they need to fit 6
into a truck from a fabricating shop to bring it up 7
into the site, you know. That's what I would think.
8 (Simultaneous speaking.)
9 DR. BLEY: Ata, may I interrupt a second?
10 MR. ISTAR: Yes.
11 DR. BLEY: If I could, Walt, I don't know 12 if you saw any of the movies they did for AP1000 as 13 they were building it, but they used a tractor kind of 14 like the ones that haul the rockets out.
15 CHAIRMAN KIRCHNER: Yes. Yes, I saw 16 those.
17 DR. BLEY: Yes. And I mean that's a 18 massive piece they were bringing out, but they did 19 have to bring it out, still, in massive pieces.
20 CHAIRMAN KIRCHNER: Yes.
21 MR. DUDEK: Mr. Kirchner, I would ask that 22 the NRC Staff not pontificate or theorize about this.
23 If we want additional details -- I mean I think we 24 still have the specialist and NuScale on the phone and 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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48 they may be able to provide some additional 1
clarification on this.
2 CHAIRMAN KIRCHNER: No, we can explore 3
this in the closed session. I know we're talking 4
about here methodology and we're not talking about the 5
detailed design of the NuScale plant.
6 MR. DUDEK: Okay.
7 CHAIRMAN KIRCHNER: So I will hold my 8
question for the closed session.
9 MR. DUDEK: All right. Thank you, sir.
10 MR. ISTAR: Thank you. Going forward, I 11 would like to elaborate a little bit more about the 12 impactive and impulsive loads and effects of 13 corrosion.
14 Impactive loads can be identified as 15 tornado missiles, pipe whip, turbine missiles, and 16 aircraft impacts.
17 Impulsive loads can be identified as jet 18 impingement, blast
- pressure, and compartment 19 pressurization.
20 The local and global effects are 21 considered due to the impactive and impulsive loads.
22 The effects of impactive and impulsive loads are 23 considered in extreme environmental and abnormal load 24 combinations concurrent with the other loads.
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49 The impactive and impulsive loads used 1
inelastic analysis and considered the limitations of 2
the ductile ratio, ductility ratio, I'm sorry, 3
ductility ratio, and the principle strain of faceplate 4
in the TR.
5 However, the limitations for rotational 6
capacity was not considered in the TR as provided in 7
Reg Guide 1.243. I will elaborate more about this in 8
the staffing relation part of it.
9 The effects of corrosion, the small 10 modular reactor designs may also consider the 11 possibility of plant license extensions up to 80 12 years.
13 In-service inspections and repair or below 14 grade exterior SC walls would be impractical for the 15 duration of an extended licensing period and there are 16 no provisions for the corrosion effects in AISC N690-17 18 and Reg Guide 1.243.
18 However, in Section 5, Section B3.13 of 19 AISC 360-16 has the general requirement that states 20 structural components shall be designed to tolerate 21 corrosion or shall be protected against corrosion.
22 Again, I will elaborate further about this 23 resolution for this in the staffing relation part.
24 Next slide, please.
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50 This particular slide shows a generic 1
straight SC wall. The materials you are presented in 2
the TR applies to straight SC wall to the requirements 3
of Appendix 9 of AISC N690 and its commentary.
4 As it can be seen from the figure, the SC 5
walls are divided into interior region and connection 6
region. Force transfer between the SC walls, the wall 7
from the composite sections between faceplates and 8
concrete and over to the connection region.
9 Connection region is designated as 10 straight along the edge of two intercepting structural 11 elements, for example slabs, walls, and basemat.
12 There were force transfer between the connected 13 elements.
14 The connection region distance is 15 considered to be less than or equal to three times the 16 wall thickness per N912 of AISC N690-18.
17 The elements in the finite element models 18 can be either a thick shell or three-dimensional solid 19 elements per N921 of AISC N690-18.
20 As discussed
- earlier, SOLSH190 and 21 SHELL181 ANSYS elements may be used in the development 22 of finite element mathematical model of SC walls.
23 Next slide, please.
24 As discussed earlier, limitations for 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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51 impactive and impulsive loads of ductility ratio and 1
the principle strain of a plate, faceplate, were 2
considered in the TR.
3 The displacement ductility ratio controls 4
the failure limit state due to the formation of 5
flexural and shear cracks in the concrete. The 6
principle strain limit controls the failure limit 7
state on the faceplates at the tension site.
8 And as stated earlier, the rotational 9
capacity of yield hinge was not considered in the TR 10 as provided in Reg Guide 1.243. The figure is from 11 paper by Dr. Amit Varma.
12 Using the test results from the paper the 13 value of rotational capacity can be estimated. Where 14 the results is comparable with the rotational capacity 15 limit in AIC-349, which is in commentary RF-34.
16 However, as stated in commentary N916B of 17 AISC 690-18, the plastic hinge rotational capacity 18 need not to be checked if the displacement ductility 19 ratio is kept under the identified limitation for 20 flexural control section.
21 Based on this review the Staff concluded 22 that consideration of limitation of ductility ratio 23 and principle strain of faceplate for the effect of 24 impactive and impulsive loads are acceptable since the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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52 TR complies with the commentary N916B of AISC N690-18.
1 Effects of corrosion, as discussed 2
earlier, the exterior below grade faceplates of SC 3
walls shall be protected from corrosive environment.
4 The following graded approach is described 5
in the TR, the application of tar epoxy coating on the 6
exterior below grade faceplate using a controlled low 7
strength material or employing a
shotcrete 8
cementitious material on the exterior below grade 9
faceplate, as well as using backfill materials with 10 controlled pH and chloride limits.
11 Based on the review of this site specific 12 graded approach the Staff found it is acceptable by 13 meeting the requirements of Section B.3.13 of AISC 14 360-16.
15 As a conclusion, meeting the provision of 16 AISC N690-18 and AISC N360-16 ensures that Seismic 17 Category I and II SC walls will perform their intended 18 safety function.
19 The Staff determined that design 20 methodology presented in the TR for the SC wall is 21 acceptable and is consistent with the acceptance 22 criteria of NuScale DSRS Section 384 and the 23 requirements in AISC N690-18 and AISC 360-16. Next 24 slide, please.
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53 In Section 7.0 of the TR presents the 1
design methodology of the SC connections that complies 2
with the requirements of AISC N690-18, AISC 360-16, 3
and ACI 349-13.
4 Basically, the connection is an assembly 5
of connectors. Connectors are -- there are numerous 6
connectors in there. I will give some examples, 7
steel-headed stud anchors, anchor ruts, tie bars, 8
couplers, welds, bolts, and post-tensioning bars and 9
shear lugs, which I will show you in the next slide 10 some of those connectors in the next slide in a 11 figure.
12 The connectors participate in the force 13 transfer mechanisms for tension, compression, in/out-14 of-plane shear, and out-of-plane flexure.
15 The connections available strength for 16 each demand types are calculated using the applicable 17 force transfer mechanisms and the available strength 18 for its contributing connectors.
19 The available strength for connectors are 20 determined per section N9.4.3 of AISC N690-18. I can 21 give some examples which the available strength of 22 these are calculated based on the different codes and 23 standards.
24 For example, for steel-headed stud anchors 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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54 the available strength is determined based on the AISC 1
360-16,Section I.8.3. For anchor ruts available 2
strength can be determined from AISC 349 Appendix D.
3 There is a user note in Section N.6 and 4
N9.4.1 of N690-18. It refers to AISC Steel Guide 32 5
for additional guidance. Although AISC Design Guide 6
32 is not a regulatory document the Staff reviewed the 7
AISC Design Guide 32 illustrations for type of 8
connections and applicable force transfer mechanisms 9
for transferring forces between SE connections.
10 The AISC Design Guide 32 discusses a 11 behavior and design of SC walls subject to the various 12 individual and combined seismic and non-seismic force 13 demands and connection types, regions, force transfer 14 mechanisms, connections philosophy, required strength, 15 available strength, connection detailing, design of SC 16 walls and connections, and demand types.
17 This is a valuable design guide that will 18 help for any designers to use during a renewal 19 application. Next slide, please.
20 The figure on the left depicts the typical 21 SC wall connection to the basemat with demands. In 22 Appendix N9.4 of N690-18 the design requirements of 23 various types of connections are provided, which are 24 basically six types.
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55 Spliced between the SC wall sections, 1
spliced between the SC wall and RC wall sections 2
connections, intersection of SC walls, connections at 3
the intersection of SC with RC walls, anchors of SC 4
walls to the RC basemat, and connection to the RC 5
walls to RC slabs.
6 The connections are designed for the 7
demand types of tensile force demand, which I showed 8
in the figure on the left, compression forces, forced 9
demands, in-plane shear demands, auto plane shear 10 demands, auto plane flexural demands.
11 The figure on the right, force transfer 12 mechanism for tensile force demand. The AC faceplate 13 to the baseplate welded resisted tensile demand on the 14 SC wall.
15 Then the force in the baseplate transfer 16 into the basemat concrete and anchor rut welded to the 17 baseplate. These are the connectors and these are 18 each one needs to be independently designed in NOIs, 19 of course.
20 Each one has associated welding for these.
21 That's how for this tension demand how the force 22 transfers into the basement goes in.
23 The connections are a design in full 24 strength. That the full strength connection design 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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56 flows develop the expected strength of the weaker of 1
the two connected parts. Next slide, please.
2 The Staff determines that design 3
methodology for the SC connections are based on the 4
provisions in AISC N690-18, AISC 360-16, and ACI 349-5 13, Appendix D.
6 The Staff found the methodology is 7
consistent with the acceptance criteria in NuScale 8
Design Specific Review Guide Section 3.8.4. Next 9
slide, please.
10 Section 8.0 of the TR provides a
11 methodology for the design of seismic Category I and 12 II structures in accordance with ACI 349-13, the 13 applicable section in ACI 318-18, and Reg Guide 1.142.
14 The design of RC structures can be 15 performed using either the match dependent and 16 element-based approach in which the stress results are 17 obtained per unit of element of the finite element 18 model, in section cut-based approach in which the 19 stress results are obtained in a member cross section 20 of a finite element model.
21 The TR refers to a technical paper titled 22 "Integrated Seismic Analysis and Design of Shear Wall 23 Structures" dated in 2008 which says the element and 24 section cut approaches, the paper concludes that 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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57 section cut approach has significant savings in RC 1
design compared to the element-based approach.
2 Based on the review Staff agreed with the 3
conclusion and confirmed the consistency with Section 4
911 of ACI 349-13.
5 Lateral and gravity load-resisting 6
systems. I will discuss this in the next slide in a 7
figure. TR describes the required strength and the 8
required strengths are determined from the finite 9
element models for slabs/basemats, columns, and T-10 beams.
11 The TR provides a figure with detailed 12 discussions for identifying the critical location of 13 section cuts for design.
14 Basically, the critical section cut 15 locations for designs are determined from stress 16 counters plus from horizontal and vertical amounts 17 resulting from in-and out-of-plane actions and 18 rectangular frame structures and basemats were used in 19 determining the critical sections. Next slide, 20 please.
21 The figure on the right provides lateral 22 and gravity load-resisting systems. The structure 23 elements are configured to resist the gravity and 24 lateral loads that are comprised of vertical elements 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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58 and horizontal elements.
1 Vertical elements extend between the 2
foundation to the elevated floors as shear walls and 3
columns. Horizontal element diaphragms consist of 4
floor slabs and roof, including cords and collectors.
5 Here the collectors is shown on this 6
picture. I will describe the cord force on the other 7
figure. Cord is defined as boundary elements in 8
structural diaphragms that resist in-plane moment or 9
tension, tension of compression forces.
10 Collectors are tension and compression 11 members that gather shear forces from diaphragms and 12 deliver them to the vertical members.
13 The figure on the left provides critical 14 section for section cut locations to determine in-15 plane shear and cord forces due to the seismic force 16 in "Y" direction.
17 This is the seismic force in "Y" direction 18 and the in-plane shears are these on both sides and 19 out-of-plane moment and cord forces on both sides. At 20 these critical locations the "P/M" interaction check 21 using ACI 349-13 is required.
22 Again, the TR provides numerous figures 23 and describes for identifying the critical locations 24 of section cuts and design.
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59 As an example, section cut locations to 1
determines out-of-plane moment, demand due to the 2
gravity and frame actions in "X" and "Y" directions.
3 I am providing the titles or the figures that was 4
provided in the TR.
5 Section cuts for one-way and two-way shear 6
in basemat subject to the wall overturning, another 7
example, section cut for out-of-plane bending in 8
basement subject to the wall overturning. Next slide, 9
please.
10 As stated earlier the critical section 11 locations for rectangular structures and basemats were 12 described in detail in the TR.
13 The appropriate lengths of critical 14 sections are used to average the load to avoid 15 unrealistic conservatism in the design.
16 The critical section lengths are 17 determined using finite element stress results, but 18 generally need not to be less than three times of the 19 RC member thickness.
20 However, the design engineer also needs to 21 justify the use of appropriate lengths at the 22 identified critical location.
23 The design methodology for RC structures 24 conforms to the conventional engineering principles by 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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60 identifying section cuts and lengths from geometric 1
configurations and design requirements of AISC 349-13, 2
the applicable sections of ACI 318-08, and Reg Guide 3
1.142, and is consistent with the acceptance criteria 4
of NuScale DSRS Section 3.8.4. Next slide, please.
5 Limitations and Conditions. Materials for 6
this TR performed linear elastically during the 7
seismic event. Nonlinear responses, liquefaction and 8
the subgrade, liquefaction of a subgrade, and the 9
significant cracking of structural components are not 10 permitted.
11 ASCE 43-19, Limit State D is applicable 12 for this TR, which as Limit State D defined as 13 expected to formation is essentially elastic behavior 14 and expected damages negligible under combined loading 15 conditions. Next slide, please.
16 CHAIRMAN KIRCHNER: Ata, this is Walt 17 again.
18 MR. ISTAR: Yes.
19 CHAIRMAN KIRCHNER: Can you go back to 20 your limitations and conditions?
21 MR. ISTAR: Yes, sir.
22 CHAIRMAN KIRCHNER: Please. Well the 23 first one I see is almost a generic statement that the 24 materials perform in a linear elastic manner.
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61 The second bullet really is to me -- when 1
I read this it struck me this is going to be site 2
specific and then you iterate on your design 3
accordingly or you change your subgrade or you change 4
your site location or something, it strikes me 5
something like liquefaction of the subgrade would be 6
a siting issue.
7 But if you had then obviously your, you 8
know, non-linear response for the building and then I 9
suppose -- I am just -- in practice for a methodology 10 I get it, but how do you actually apply this?
11 MR. ISTAR: You know, the site, this is 12 again it's a site specific issue, and based on the 13 methodologies provided in the TR liquefaction of the 14 subgrade is not expected or it's not going to happen.
15 If it happens, of course, which is not a 16 good thing, and significant cracking of structure 17 components are not supposed to be happening.
18 CHAIRMAN KIRCHNER: Well, see, the second 19 part -- the first part is site specific. The second 20 part is design specific.
21 MR. ISTAR: Correct. Correct.
22 CHAIRMAN KIRCHNER: And that one, okay, 23 what you are saying is when you complete your design 24 for your design basis safe shutdown earthquake you 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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62 have to demonstrate that you do not have significant 1
cracking.
2 MR. ISTAR: Yes.
3 DR. BLEY: Walt, this is Dr. --
4 CHAIRMAN KIRCHNER: And then reinforce or 5
redesign until the structure that is in question 6
doesn't significantly crack. Go ahead, Dennis.
7 DR. BLEY: Yes. This is just -- the way 8
I see this is from the Staff this is just saying you 9
can't use this Reg Guide if in fact you might have 10 liquefaction, but then you have to do what you were 11 just saying, which is maybe the Staff would be, they 12 would have to look at some detailed analyses.
13 Staff, that's really my estimation of what 14 you are trying to say. Tell me if I am right or 15 wrong.
16 MR.
ISTAR:
I mean the
- report, 17 liquefaction -- I can't -- I am having problems 18 pronouncing this word.
19 MR. COLACCINO: Hey, Ata?
20 MR. ISTAR: Yes, sir?
21 MR. COLACCINO: Ata?
22 MR. ISTAR: Yes?
23 MR. COLACCINO: I think what was just said 24 was exactly what we would do.
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63 MR. ISTAR: Yes. Yes, sir. That's what 1
I was going to repeat.
2 MR. COLACCINO: Okay. I thought that's 3
where you were getting -- so you can avoid saying 4
liquefaction.
5 MR. ISTAR: Yes. Yes. Thank you. Thank 6
you, Joe.
7 MR. COLACCINO: That was Joe Colaccino, 8
sorry.
9 MR. ISTAR: Yes. Thank you.
10 MEMBER REMPE: Walt?
11 CHAIRMAN KIRCHNER: Go ahead, Joy.
12 MEMBER REMPE: Well maybe Dennis's 13 response is also the answer to my question, but when 14 I look at the SE as well as the words on the slide I 15 was wondering I mean during all seismic events or 16 seismic events down to a certain frequency or is it 17 that if you look at all of the design basis events and 18 they don't perform elastically then you've got to use 19 something else or is -- what would that something else 20 be?
21 I just was wondering down to what 22 frequency of seismic events, but maybe, again, 23 Dennis's response also clarifies that.
24 I was just kind of puzzled I think with 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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64 the same kind of thing you are thinking about, too, is 1
what happens if it doesn't. Yes, I -- does that make 2
sense what I am trying to ask or is it --
3 MR. ISTAR: Yes, it makes sense, but, 4
again, I think I am going to repeat myself. The TR 5
liquefaction of subgrade is not allowed based on the 6
methodologies provided in this TR. That's --
7 MEMBER REMPE: But I am not talking about 8
the second bullet, I'm talking about the first one.
9 What if during --
10 MR. ISTAR: Oh, okay, for --
11 MEMBER REMPE: Yes, down to what frequency 12 of seismic events? Every seismic event? Beyond 13 design basis earthquakes? Design basis earthquakes?
14 MR. ISTAR: Well, that's a good question.
15 The CSDRS is performed and whatever the applicable 16 CSDRS, there are five of them, as I elaborated 17 earlier, and which they should, the structure will be 18 within the elastic limits using those CSDRS motions.
19 CHAIRMAN KIRCHNER: So, Ata, what I took, 20 picked up from that, when you actually go to build a 21 plant at a specific site, kind of related to Joy's 22 question, then what you are going to do and practice 23 is get agreement, the applicant is going to get 24 agreement with the NRC about what the safe shutdown 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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65 earthquake is, what the spectra is, and so on for that 1
site.
2 MR. ISTAR: Correct.
3 CHAIRMAN KIRCHNER: And then the applicant 4
will do his or her detailed analyses to demonstrate 5
that it's linear. Obviously, they would demonstrate 6
also that there is not liquefaction, et cetera.
7 So it seems to me it's an iterative thing.
8 What was done in the TR was to pick five -- what did 9
they do again, five spectra?
10 MR. ISTAR: Yes, sir.
11 CHAIRMAN KIRCHNER: Five spectra and bound 12 it and three soil types and bound that. So, Joy, I 13 think they enveloped a credible range of seismic 14 inputs wherein the TR and the methodology would be 15 valid.
16 MEMBER REMPE: And then if it's not 17 they'll just go to a different site or something like 18 that is what you're saying, and so it will go even to 19 beyond design basis events?
20 MR. ISTAR: Well, I don't want to speak 21 for the applicant. If they don't -- you know, those 22 are major earthquakes that it was, you know, they 23 covered quite a bit of range in their response 24 inspector.
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66 If the site were not to be enveloped by 1
those they have to redesign the structure as the 2
methodology has provided in this topical report.
3 MEMBER REMPE: Okay. That makes sense.
4 I just -- I thought it was -- I wasn't quite sure what 5
it meant that way. Thank you.
6 MR. ISTAR: Yes. You know, another 7
limitation that maybe we should have had in this list, 8
whatever the CSDRS is listed in this topical report, 9
but I think -- well, anyway. Okay. Any other 10 questions?
11 Next slide, please. In conclusion, the 12 methodologies presented in the NuScale TR are 13 acceptable to perform the building design analysis for 14 seismic Category I and II structures safety-related RC 15 and SC structures other than the containment.
16 The methodologies follow implementation of 17 the requirements of AIC 349-13, AISC N690-18, Appendix 18 9, endorsed by Reg Guide 1.243.
19 The methodologies are also consistent with 20 the applicable regulatory requirements of acceptance 21 criteria in NRC NuScale DSRS Sections 3.7.2 and 3.8.4.
22 That concludes my presentation. I can take any other 23 questions that you may have. Thank you.
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67 again.
1 MR. ISTAR: Okay.
2 CHAIRMAN KIRCHNER: Let me start with your 3
first bullet. Basically, you say that this 4
methodology is acceptable for building design and 5
analysis for Cat I and II's safety-related RC and SC 6
structures.
7 Then you go on to say "other than 8
containment." Now basically is that because there is 9
another Reg Guide for a conventional containment that 10 you would use as a guidance?
11 MR. ISTAR: Yes. And as RC walls are not 12 pressure rated walls and, therefore --
13 (Simultaneous speaking.)
14 CHAIRMAN KIRCHNER: Okay, so that's the 15 distinction.
16 MR. ISTAR: That's the distinction on any 17 containment wall or pressure retaining structures.
18 CHAIRMAN KIRCHNER: Right.
19 MR.
ISTAR:
And that's where the 20 difference comes in. There is a trend to get the RC 21 walls into ASME code, and which I am part of that, and 22 then there is a lot of discussions why is it, as you 23 know ASME is considering all of the pressurized 24 components, not the -- and there are a lot of members 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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68 questioning whether this should be within the Division 1
2 of Section 3 of ASME.
2 So I don't know what the resolution is 3
going to be. Some members think that is doable, some 4
members think that's not doable. I don't know what 5
are the NRC's positions at this point and --
6 (Simultaneous speaking.)
7 CHAIRMAN KIRCHNER: I was just thinking.
8 I asked that because, you know, the underlying 9
methodology relying on ANSYS and the other methodology 10 that you previously reviewed and we reviewed that was 11 submitted on soil structure libraries, these are kind 12 of generic things.
13 The codes that are referenced here from 14 both the steel and the concrete codes and the 15 standards are basically kind of generic. That's why 16 I asked the question other than containment, but the 17 main thing is that the containment is a pressure 18 boundary.
19 MR. ISTAR: Correct, pressure rated.
20 CHAIRMAN KIRCHNER: Okay. Thank you.
21 MR. ISTAR: You're welcome. Thank you.
22 CHAIRMAN KIRCHNER: Members, further 23 questions?
24 Not hearing any, any comments, Members, at 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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69 this point? We'll have another opportunity in a 1
little bit in a closed session to pursue further 2
questions if you don't have any right now.
3 Okay. With that, then, Mike Snodderly, I 4
think we should turn and provide the public an 5
opportunity to comment.
6 MR. SNODDERLY: Yes. Any member of the 7
public may unmute their phone and make a comment if 8
they would like. Ms. Fields, are you on?
9 CHAIRMAN KIRCHNER: I'll repeat the offer 10 again. Any member of the public wish to make a 11 comment please identify yourself and make your 12 comment.
13 MEMBER REMPE: Mike and Walt, do they have 14 to press *6 in order to unmute themselves or is it 15 open for everybody right now?
16 MR. SNODDERLY: You're right, Member 17 Rempe. Please press *6 to unmute yourselves.
18 CHAIRMAN KIRCHNER: Okay.
19 MR. SNODDERLY: I think we're okay, Walt.
20 I have been watching my email and Sarah wasn't on at 21 the beginning of the meeting and she didn't --
22 sometimes if she has trouble connecting she'll send me 23 an email and I didn't get anything, so I think we've 24 given them a sufficient opportunity.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
70 CHAIRMAN KIRCHNER: Okay.
1 MR. SNODDERLY: Thanks.
2 CHAIRMAN KIRCHNER: And any other Member 3
of NuScale or Staff wish to make a comment in an open 4
session this would be fine. While you are thinking of 5
a comment what I will do is we'll take a break here 6
shortly.
7 I think we're coming up on the scheduled 8
break time at 3:45. So if there are no further 9
comments we will take a break from now until 4 o'clock 10 p.m. Eastern Standard Time.
11 MEMBER BALLINGER: Walt, we have a 12 separate invitation for the closed session, right?
13 MR. SNODDERLY: That's correct.
14 CHAIRMAN KIRCHNER: Yes. Yes.
15 MR. SNODDERLY: This meeting will end and 16 those that have a need to know will go to the closed 17 session and every Member should have an invitation to 18 that.
19 If you don't send me an email and I will 20 make sure we get you on. But the closed session has 21 been activated, so you can go whenever you feel --
22 CHAIRMAN KIRCHNER: Okay.
23 MR. SNODDERLY: And as Member Kirchner 24 said we would, in accordance with the schedule we'll 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
71 start at 4 o'clock.
1 CHAIRMAN KIRCHNER: On the closed session.
2 MR. SNODDERLY: Yes.
3 CHAIRMAN KIRCHNER: So this will complete 4
the open session involving the public of this 5
subcommittee meeting. Thank you, everyone.
6 MR. SNODDERLY: And I would ask the 7
transcriber to also go to the closed session.
8 CHAIRMAN KIRCHNER: Thank you, Mike.
9 MR. SNODDERLY: Okay.
10 CHAIRMAN KIRCHNER: Okay. With that this 11 open session is closed, and we will return in a closed 12 session, and you have an invitation for that, at 4 13 o'clock Eastern Time. Thank you.
14 (Whereupon, the above-entitled matter went 15 off the record at 3:43 p.m.)
16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
LO-111763 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360-0500 Fax 541.207.3928 www.nuscalepower.com January 12, 2022 Docket No. 99902078 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738
SUBJECT:
NuScale Power, LLC Submittal of Presentation Materials Entitled ACRS Subcommittee Meeting: NuScale Building Design and Analysis Methodology for Safety-Related Structures (Open Session), PM-111761, Revision 0 The purpose of this submittal is to provide presentation materials to the NRC for use during the upcoming Advisory Committee on Reactor Safeguards (ACRS) Subcommittee Meeting on January 19, 2022. The materials support NuScales presentation of the topical report "NuScale Building Design and Analysis Methodology for Safety-Related Structures,"
TR-0920-71621, Revision 1.
The enclosure to this letter is the nonproprietary presentation entitled ACRS Subcommittee Meeting: NuScale Building Design and Analysis Methodology for Safety-Related Structures (Open Session), PM-111761, Revision 0.
This letter makes no regulatory commitments and no revisions to any existing regulatory commitments.
If you have any questions, please contact Liz English at 541-452-7333 or at EEnglish@nuscalepower.com.
Sincerely, Mark W. Shaver Manager, Licensing NuScale Power, LLC Distribution: Michael Dudek, NRC Getachew Tesfaye, NRC Bruce Bavol, NRC
Enclosure:
ACRS Subcommittee Meeting: NuScale Building Design and Analysis Methodology for Safety-Related Structures (Open Session),
PM-111761, Revision 0
LO-111763 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360-0500 Fax 541.207.3928 www.nuscalepower.com
Enclosure:
ACRS Subcommittee Meeting: NuScale Building Design and Analysis Methodology for Safety-Related Structures (Open Session), PM-111761, Revision 0
Copyright 2022 by NuScale Power, LLC.
Revision:0 Template #: 0000-21727-F01 R7 NuScale Nonproprietary ACRS Subcommittee Meeting NuScale Building Design and Analysis Methodology for Safety-Related Structures January 19, 2022 (Open Session)
Copyright 2022 by NuScale Power, LLC.
Revision:0 Template #: 0000-21727-F01 R7 Presenters Fehmida Mesania, Ph.D., P.E.
Licensing Engineer Evren Ulku, Ph.D., P.E.
Supervisor, Civil Structural
Copyright 2022 by NuScale Power, LLC.
Revision:0 Template #: 0000-21727-F01 R7 Agenda
- Purpose
- Introduction
- Steel-plate composite (SC) Walls
- Reinforced concrete (RC) members
- In-structure response spectra (ISRS)
- Effective stiffness modeling approach
Copyright 2022 by NuScale Power, LLC.
Revision:0 Template #: 0000-21727-F01 R7 Purpose
- Present technical content of topical report TR-0920-71621
- Provide a general understanding of building design and analysis methodology for seismic Category I and II nuclear safety-related reinforced concrete (RC) and steel-plate composite (SC) structures applicable to NuScale design
Copyright 2022 by NuScale Power, LLC.
Revision:0 Template #: 0000-21727-F01 R7 Introduction - Timeline
- NuScale submitted topical report TR-0920-71621, Revision 0, Building Design and Analysis Methodology for Safety-Related Structures, - December, 2020 (ADAMS Accession No. ML20353A404)
- NRC accepted the topical report for review - February, 2021
- NRC completed detailed technical review via RAIs -9833,
-9834 and -9860, October, 2021
- NuScale issued topical report Revision 1 - October, 2021(ADAMS Accession No. ML21279A336)
- NRC issued draft Safety Evaluation Report (SER) -
November, 2021
Copyright 2022 by NuScale Power, LLC.
Revision:0 Template #: 0000-21727-F01 R7 Introduction - Topical Report
- Topical report presents a design methodology implementing new industry standards for nuclear facilities
- Applicable to new generation SMR designs
- Complies with reinforced concrete and SC walls requirements
- Defines design methodologies to account for the interaction of SC walls with traditionally constructed RC members such as basemats, slabs, and roofs
- Implements the soil library methodology for complex structures as per NuScale topical report, Improvements in Frequency Domain Soil-Structure-Fluid Interaction Analysis, TR-0118-58005-P-A, Revision 2
- Topical report information will be used as part of SDAA submittal
Copyright 2022 by NuScale Power, LLC.
Revision:0 Template #: 0000-21727-F01 R7 Introduction - Building Design Evren Ulku, Ph.D., P.E.
Supervisor, Civil Structural
Copyright 2022 by NuScale Power, LLC.
Revision:0 Template #: 0000-21727-F01 R7 Steel-Composite Walls
- Steel-Plate Composite Walls
- Steel faceplates with concrete core
- Anchors to ensure composite behavior
- Ties to ensure integrity
Copyright 2022 by NuScale Power, LLC.
Revision:0 Template #: 0000-21727-F01 R7 SC Walls - Insight
- Advantages Higher resistance to blast and earthquake, higher ultimate strength Modular constructionreduction in fabrication and erection time
- Use of several common module layouts repeated throughout elevation
- Smaller, lighter modules that are more easily transportable
- Areas requiring special attention Connection with reinforced concrete (RC) elements (i.e., basemat and floors)
Requires below grade mitigation of corrosion effects
PM-111761 10 Copyright 2022 by NuScale Power, LLC.
Revision:0 Template #: 0000-21727-F01 R7 Reinforced Concrete
- RC design methodology is based on the requirements of American Concrete Institute, ACI 349-13 Code Requirements for Nuclear Safety-Related Concrete Structures and ACI 318-08 Building Code Requirements for Structural Concrete.
- RC members include:
- Basemat
- Floor slabs
- Roof slab
PM-111761 11 Copyright 2022 by NuScale Power, LLC.
Revision:0 Template #: 0000-21727-F01 R7 ISRS & Design Methodology
- Implements NuScale Topical Report Improvements in Frequency Domain Soil-Structure-Fluid Interaction Analysis, (TR-0118-58005-P-A, Rev 2), to obtain ISRS for subsystem design and member forces for design of Seismic Category I/II structures, systems, and components (SSC)
- Provides analytical models for complex structures with damping values and stiffness properties based on the actual stress state of members under the most critical seismic load combination
- Consistent with latest safety-related codes and standards:
PM-111761 12 Copyright 2022 by NuScale Power, LLC.
Revision:0 Template #: 0000-21727-F01 R7 Effective Stiffness
- Describes modeling approach to represent effective stiffness for RC wall/slab members and for SC walls for Seismic Category I/II structures
- Effective stiffness values are taken from codes and standards Force Disp Force Displacement Force uncracked Cracked (uncracked)
(effective)
PM-111761 13 Copyright 2022 by NuScale Power, LLC.
Revision:0 Template #: 0000-21727-F01 R7 Acronyms ACI American Concrete Institute AISC American Institute of Steel Construction ANSI American National Standards Institute ISRS In-structure Response Spectra NRC Nuclear Regulatory Commission RAI Request for Additional Information RC Reinforced Concrete SC Steel-plate Composite SDAA Standard Design Approval Application SMR Small Modular Reactor SER Safety Evaluation Report SSC Structures, Systems and Components
PM-111761 14 Copyright 2022 by NuScale Power, LLC.
Revision:0 Template #: 0000-21727-F01 R7 http://www.nuscalepower.com Twitter: @NuScale_Power Portland Office 6650 SW Redwood Lane, Suite 210 Portland, OR 97224 971.371.1592 Corvallis Office 1100 NE Circle Blvd., Suite 200 Corvallis, OR 97330 541.360.0500 Rockville Office 11333 Woodglen Ave., Suite 205 Rockville, MD 20852 301.770.0472 Richland Office 1933 Jadwin Ave., Suite 130 Richland, WA 99354 541.360.0500 Charlotte Office 2815 Coliseum Centre Drive, Suite 230 Charlotte, NC 28217 980.349.4804
Staff Presentation to the ACRS Sub-Committee NuScale Topical Report Building Design and Analysis Methodology for Safety-Related Structures (TR-0920-71621, Revision 1)
JANUARY 19, 2022
2 Topical Report Review Chronology
3 NRC Staff Reviewers:
- Ata Istar, Structural Engineer, NRR/DEX/ESEB
- Amitava Ghosh, Ph.D., Geotechnical Engineer, NRR/DEX/ESEB
- Robert Pettis, P.E. (Retired) Sr. Reactor Engineer, NRR/DEX/ESEB Project Managers:
- Demetrius Murray, TR Project Manager, NRR/DNRL/NRLB
- Getachew Tesfaye, Sr. Project Manager, NRR/DNRL/NRLB
4 Agenda
- Introduction
- Regulatory Bases
- Background
- NuScale TR Presented Methodologies
- Staff Review and Evaluation
- Limitations and Conditions
- Staff Conclusions
5 Introduction NuScale Topical Report (TR) offers design and analysis methodologies to be used in the evaluation of Seismic Category I and II structures, applicable to the new generation of small modular reactors (SMRs).
6 Regulatory Bases NRC Regulations 10 CFR Part 50, Appendix A, GDC 2: SSCs important to safety must be designed to withstand the effects of natural phenomena such as earthquakes.
10 CFR Part 50, Appendix A, GDC 4: SSCs important to safety must be designed to accommodate the effects of environmental conditions associated with normal operation, maintenance, testing, and postulated accidents.
10 CFR Part 50, Appendix S: Safety functions of SSCs subject to earthquake ground motion must be assured through design, testing, or qualification methods, and that the evaluation must consider soil-structure interaction effects.
7 Guidance Documents
- RG 1.243, "Safety-Related Steel Structures and SC Walls for Other Than Reactor Vessels and Containments," recently endorsed ANSI/AISC N690-18 (hereinafter referred as N690-18).
- RG 1.142 Safety-Related Concrete Structures for Nuclear Power Plants (Other than Reactor Vessels and Containments)
- RG 1.199 Anchoring Components and Structural Supports in Concrete
- RG 1.61 Damping Values for Seismic Design of Nuclear Power Plants
- RG 1.122 Development of Floor Design Response Spectra for Seismic Design of Floor-Supported Equipment or Components
8 Guidance Documents-cont.
- NRC NuScale, Design-Specific Review Standards (DSRSs)
- Section 3.7.2, Seismic System Analysis,
- Section 3.8.4, Other Seismic Category I Structures.
9 Codes/Standards
- ANSI/AISC N690-18, Specification for Safety-Related Steel Structures for Nuclear Facilities.
- ANSI/AISC 360-16, American National Standards Institute/American Institute of Steel Construction.
- ACI 349-13, "Code Requirements for Nuclear Safety-Related Concrete Structures and Commentary.
- ACI 318-08, American Concrete Institute, Building Code Requirements for Structural Concrete and Commentary.
- ASCE 43-19, Seismic Design Criteria for Structures, Systems, and Components in Nuclear Facilities.
- ASCE 4-16, Seismic Analysis of Safety-Related Nuclear Structures and Commentary.
10 Background
The NuScale TR presents methodologies of the design and analysis of seismic Category I and II structures:
- Effective stiffness of members (TR Section 5.0).
- Steel-Plate composite (SC) walls and connections (TR Sections 6.0 and 7.0).
- Reinforced concrete (RC) structures (TR Section 8.0).
11 Background - cont.
- The methodology for the design and analysis of SC walls is in accordance with N690-18, endorsed in RG 1.243.
- The methodology for the design and analysis of RC structures is in accordance with ACI 349-13, endorsed in RG 1.142, "Safety-Related Concrete Structures for Nuclear Power Plants (Other than Reactor Vessels and Containments)."
12 TR Section 4.0: Determination of ISRS and Design of Structural Members
- ANSYS Triple Building (TRB) models includes Reactor Building, Control Building, Radioactive Waste Building.
- TRB Seismic Model: determines member forces and ISRS.
- TRB Static Model: determines member forces from non-seismic load combinations.
- Three Soil Libraries were considered:
- Type 11 (soft soil), Type 7 (rock), Type 9 (hard rock).
- Five certified seismic design response spectra (CSDRS) for soil types 7 and 11: Capitola, Chi-Chi, El Centro, Izmit, and Yermo.
- One CSDRS-high frequency (CSDRS-HF) for Soil type 9: Lucerne.
13 TR Section 4.0: Determination of ISRS and Design of Structural Members
- Check walls and slabs for cracking in in-plane shear and in-plane bending.
- All cracked RC members: assign effective stiffness and damping per ASCE/SEI 4-16 and ASCE/SEI 43-19.
- All cracked SC members: assign effective stiffness per N690-18 and damping per ASCE/SEI 43-19.
- New analysis using CSDRS and CSDRS-HF is performed with updated stiffness and damping values.
- Damping values are consistent with RG 1.61.
TR Section 4.0: Determination of ISRS and Design of Structural Members - cont.
Determination of Member Forces
- Combine member forces from TRB Seismic and TRB Static at each time step.
- In-plane stiffnesses matched in both models (seismic and static).
- Add reinforcement if Demand to Capacity (DCR) > 1.0.
- Envelope reinforcement and determine controlling DCR for each member.
- Re-perform analysis for each soil type with appropriate CSDRS or CSDRS-HF.
to determine final reinforcement.
Determination of ISRS
- Determine ISRS at required locations as algebraic sum of time histories.
- Determine average ISRS and broaden peak by +/-15% for uncertainties (per RG 1.122)
- Repeat for each soil type with appropriate CSDRS or CSDRS-HF.
- Envelope ISRS.
Staff finds both approaches consistent with DSRS Section 3.7.2.
14
15 TR Section 5.0: Determination of Effective Stiffness
- Effective stiffness
- RC walls and slabs modeled using factors given in Table 3-2 of ASCE/SEI 4-16.
- SC walls modeled using Section N9.2.2 of N690-18.
- Sec. N9.2.3 of N690-18 for SC walls:
An elastic FE model of SC section geometric and material properties
- Poissons ratio of concrete
- Section thickness and elastic moduli through calibration to match
- Density through calibration From AISC Steel Design Guide 32
16 TR Section 5.0: Effective Stiffness Staff Review and Evaluation
- Two alternate methodologies of Effective Stiffness and Density
- Method 1: A single orthotropic material with dummy outer layers (zero density and insignificant moduli) for both RC and SC walls.
o Middle layer effective elastic properties from ASCE 4-16 and N690-18
- Method 2:
o Different material properties for middle and outer layers from ASCE 4-16 and N690-18 for SC walls only.
- Implemented solid-shell element SOLSH190 and shell element SHELL181 in ANSYS.
- Orthotropic material properties (3 Youngs moduli, 3 shear moduli, and 3 Poissons ratios) are used.
- The approaches to determine these properties are acceptable.
TR Section 5.0: Effective Stiffness Staff Review and Evaluation - cont.
- TR includes five Implementation examples to illustrate and validate the use of the proposed methodologies using ANSYS.
- Models with SOLSH190 using both Methods 1 and 2 produce similar results.
- SHELL181 results agree with SOLSH190 results although calculated frequencies with SHELL181 are slightly lower.
- SOLSH190 better represents connection region and preferred.
- SHELL181 can represent open spans accurately.
- Staff finds methodologies used conforms to NuScale DSRS Sections 3.7.2 and 3.8.4, and RG 1.243.
17
18 TR Section 6.0: Design of SC Walls
- Design methodology for SC walls complies with the requirements of AISC N690-18, Appendix N9, and AISC 360-16.
- Specification requirements:
Design Impactive and Impulsive Loads Analysis - Required Strength Design of SC walls - Available Strength Required Strength Available Strength Corrosion Effects
19 TR Section 6.0: Design of SC Walls -
cont.
From N690-18, Appendix N9, Commentary
20 TR Section 6.0: Design of SC Walls Staff Review and Evaluation
- Effects of corrosion of below-grade exterior sections of SC walls was not addressed.
- Methodology for the SC wall connection is acceptable and consistent with NuScale DSRS 3.8.4, and N690-18 and AISC 360-16 as endorsed by 1.243.
- Rotational capacity of any yield hinge less than or equal to 0.07 radian (4°)
was not considered as a limit under impactive and impulsive loads as it was provided in RG 1.243 as one of the three limitation for flexural-control.
Paper by Dr. Varma, et al.
21 TR Section 7.0: Design of SC Wall Connections
- The methodology presented complies with the requirements of N690-18 and AISC 360-16, and ACI 349-13.
- The methodology presented the development of available strength for each demand type using the appropriate force transfer mechanism (FTM).
- Connectors participate in the FTMs for tension, compression, in/out-of-plane shear, and out-of-plane flexure.
- User Note in Section N9.4.1 of N690-18 refers to the use of AISC Steel Design Guide 32 which presents numerous figures of connection types and FTMs implementing the provisions of N690-18, Appendix N9.
22 TR Section 7.0: Design of SC Wall Connections - cont.
Typical SC wall connection to basemat with demands Force Transfer Mechanism (FTM) for Tensile Demand T of C V
M
23 TR Section 7.0: Design of SC Wall Connections Staff Review and Evaluation
- Methodology for the SC wall connection is acceptable and consistent with NuScale DSRS 3.8.4, and AISC N690-18 as endorsed by 1.243 and AISC 360-16, and ACI 349-13 as endorsed by RGs 1.199, and 1.142.
24 TR Section 8.0: Design of RC Structures
- Design Requirements for RC seismic Category I and II structures are based on ACI 349-13 and the applicable Section in ACI 318-08.
- Section Cut-Based Methodology: was used in which stress results are obtained in member cross sections of RC seismic Category I and II structures.
- Lateral and Gravity Load-Resisting Systems.
- Required Strengths for design of slabs/basemats, columns, T-beams form FEA.
- Critical location where the largest demand is expected for design.
25 TR Section 8.0: Design of RC Structures - cont.
Critical locations of section-cuts, demand due seismic force in y direction Lateral and Gravity Load-Resisting Systems X
y P, Mx P, Mx Ny V
V z
From the NIST guide
26 TR Section 8.0: Design of RC Structures Staff Review and Evaluation
- Section Cut-Based Methodology
- Determining the section cut length.
- The design methodology for the RC structures conforms to conventional engineering principles for identifying section cuts and lengths.
- The methodology is consistent with the applicable sections of the ACI codes and the acceptance criteria in NuScale DSRS, Section 3.8.4.
27 Limitations and Conditions
- Materials perform linear elastically during seismic events.
- Nonlinear response, e.g., liquefaction of the subgrade and significant cracking of structural components, are not permitted (ASCE 43-19, Limit State D).
28 Staff Conclusions
- The methodologies presented in the NuScale TR are acceptable to perform building design and analysis for seismic Category I and II nuclear safety-related RC and SC structures other than containment.
- The methodologies follow implementation of the requirements of ACI 349-13 and AISC N690-18, Appendix N9, endorsed by RG 1.243.
- The methodologies are also consistent with the applicable regulatory requirements of acceptance criteria in NRC NuScale DSRS Sections 3.7.2 and 3.8.4.
29 Thank You for Your Attention Any Questions?
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