ML19282A373
| ML19282A373 | |
| Person / Time | |
|---|---|
| Issue date: | 09/05/2019 |
| From: | Michael Snodderly Advisory Committee on Reactor Safeguards |
| To: | |
| Snodderly, M, ACRS | |
| References | |
| NRC-0552 | |
| Download: ML19282A373 (81) | |
Text
Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION
Title:
Advisory Committee on Reactor Safeguards Open Session Docket Number:
(n/a)
Location:
Rockville, Maryland Date:
Thursday, September 5, 2019 Work Order No.:
NRC-0552 Pages 1-49 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 666TH MEETING 4
ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 5
(ACRS) 6
+ + + + +
7 THURSDAY 8
SEPTEMBER 5, 2019 9
+ + + + +
10 ROCKVILLE, MARYLAND 11
+ + + + +
12 The Advisory Committee met at the Nuclear 13 Regulatory Commission, Two White Flint
- North, 14 Room T2B3, 11545 Rockville Pike, at 8:30 a.m., Peter 15 Riccardella, Chairman, presiding.
16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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2 COMMITTEE MEMBERS:
1 PETER RICCARDELLA, Chairman 2
MATTHEW W. SUNSERI, Vice Chairman 3
JOY L. REMPE, Member-at-Large 4
RONALD G. BALLINGER, Member 5
CHARLES H. BROWN, JR., Member 6
MICHAEL L. CORRADINI, Member 7
VESNA B. DIMITRIJEVIC, Member 8
WALTER L. KIRCHNER, Member 9
JOSE MARCH-LEUBA, Member*
10 DAVID PETTI, Member 11 HAROLD B. RAY, Member 12 13 14 DESIGNATED FEDERAL OFFICIAL:
15 ZENA ABDULLAHI 16 MIKE SNODDERLY 17 18
- Present via telephone 19 20 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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3 CONTENTS 1
Westinghouse Topical Report, WCAP-17794 2
Related to New D5 CPR Correlation for 3
SVEA-96 Optima-3 Fuel Design 4
4 Topical Report 0716-50351, NuScale 5
Applicability of AREVA Method for the 6
Evaluation of Fuel Assembly Structural 7
Response to Externally Applied Forces... 13 8
Adjourn..................... 49 9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 P-R-O-C-E-E-D-I-N-G-S 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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4 (8:30 a.m.)
1 CHAIRMAN RICCARDELLA: Good morning. The 2
meeting will come to order.
3 This is the second day of the 666th 4
meeting of the Advisory Committee on Reactor 5
Safeguards. I am Pete Riccardella, ACRS Chairman.
6 The ACRS was established by the Atomic 7
Energy Act and is governed by the Federal Advisory 8
Committee Act, FACA.
9 The ACRS section of the U.S. NRC public 10 website provides information about the history of the 11 ACRS and provides FACA-related documents, such as our 12
- charter, bylaws, Federal Register Notices for 13 meetings, letter reports, and transcripts of all full 14 and subcommittee meetings, including all slides 15 presented at the meetings.
16 The committee provides advice on safety 17 matters to the Commission through its publicly 18 available letter reports. The Federal Register Notice 19 announcing the meeting was published on August 6th and 20 provided an agenda and instructions for interested 21 parties to provide written documents and request 22 opportunities to address the committee, as required by 23 FACA.
24 In accordance with FACA, there is a 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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5 Designated Federal Official. At today's meeting, the 1
DFO is Ms. Zena Abdullahi.
2 During today's meeting, the committee will 3
consider the following: Westinghouse Topical Report, 4
WCAP-17794, Related to New D5 CPR Correlation for 5
SVEA-96 Optima-3 Fuel Design; and, two, Topical Report 6
0716-50351, NuScale Applicability of AREVA Method for 7
the Evaluation of Fuel Assembly Structural Response to 8
Externally Applied Forces; and also Preparation of 9
ACRS Reports.
10 As reflected in the agenda, portions of 11 the sessions on both of these topical reports may be 12 closed in order to discuss and protect information 13 designated as sensitive or proprietary.
14 There is a phone bridge line. To prevent 15 interruption of the meeting, the phone will be placed 16 in listen-only mode during the presentations and 17 committee discussion.
18 We have received no written comments or 19 requests to make statements from members of the public 20 regarding today's sessions. There will be an 21 opportunity for public comment, as we have set aside 22 10 minutes in the agenda for comments from the members 23 of the public attending or listening to our meeting.
24 Written comments may be forwarded to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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6 Ms. Abdullahi, the Designated Federal Official.
1 A transcript of open portions of the 2
meeting is being kept, and it is requested that the 3
speakers use one of the microphones, identify 4
themselves, and speak with sufficient clarity and 5
volume, so that they can be readily heard.
6 And with that, I will request that 7
everybody silence their cell phones or other devices, 8
and we will proceed.
9 So I turn the meeting over to Member-at-10 Large Rempe.
11 MEMBER REMPE: Thank you. So on 12 October 21st of this year, our Thermal Hydraulics 13 Subcommittee completed our review of the Westinghouse 14 Electric Company Topical Report WCAP-17794, which 15 describes the new D5 CPR correlation for SVEA-96 fuel, 16 Optima-3 fuel.
17 And at the end of our subcommittee 18 meeting, we recommended that this topic be brought to 19 the full committee. And today we are going to hear 20 from the staff on this topic, but my understanding is 21 that there are Westinghouse staff members available on 22 the phone line to respond to any member questions if 23 the staff can't respond to such questions.
24 I would note that the staff is going to be 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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7 giving two presentations. This first presentation is 1
an open presentation, and at the end of it we will 2
call for public comments, if there are any, and then 3
we're going to close the meeting and the staff will 4
give a second presentation.
5 And after that, there is a letter, and 6
Jose March-Leuba, who is on the line because of the 7
hurricane instead of being here, has drafted that 8
letter. And I'm just acting for him, but I will read 9
it for him. And if there are difficult questions, 10 I'll rely on Jose to answer those questions, too, 11 assuming his phone line stays connected.
12 So with that, I will turn it over to Josh.
13 MEMBER KIRCHNER: Just one correction for 14 the record. It was August, the subcommittee meeting.
15 MEMBER REMPE: Did I say something other 16 than August?
17 MEMBER KIRCHNER: October.
18 MEMBER REMPE: Oh. Excuse me. Thank you.
19 I misread it.
20 MEMBER KIRCHNER: Just for the record.
21 MEMBER REMPE: Brain failure there. Thank 22 you.
23 MR. KAIZER: Thank you very much. Good 24 morning. My name is Joshua Kaizer, along with Reed 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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8 Anzalon. We will be presenting today the safety 1
evaluation for the D5.
2 Can you go to the next slide, Reed?
3 This is a very -- it's a unique safety 4
evaluation for the NRC. We have done about 40 of 5
these safety evaluations for critical heat flux and 6
critical power models in the past. We are very used 7
to those.
8 But this safety evaluation had the unique 9
-- the experience that happened at KKL where they had 10 a single fuel failure and a whole bunch of indications 11 made the staff go back and look at the possibility 12 that the experimental data was not actually capturing 13 the phenomenon occurring in the reactor. And that is 14 why we have had so much attention on this SE and this 15 review.
16 Here I have just kind of shown that we 17 have three authors of the SE -- myself, Reed, and Josh 18 Whitman. We have three reviewers -- John Lehning, Ben 19 Parks, Paul Clifford. None of those are junior 20 people. I would say they are all very experienced.
21 This is extremely unusual. In every other case, I 22 think we have looked at three or four SEs that have 23 been similar to this, reviews that have been similar 24 to this over the past couple of years.
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9 It has been either I do the review and 1
Reed is the peer reviewer, or Reed does the review and 2
I am the peer reviewer. So to have this many people, 3
and it was solely because we are wondering, okay, does 4
the evidence that we saw in KKL, did that say that 5
there was an issue with the experiments and the 6
correlations in general?
7 MR. ANZALON: Or with the fuel design.
8 MR. KAIZER: Yeah. So that was -- that 9
was the heightened, and that was one of the reasons 10 that I think that this topical report was brought to 11 the attention of ACRS. I mean, obviously, you guys 12 are able to look at anything you guys want to, but 13 this was especially, hey, we have something new and 14 unique here, and those are of special interest to the 15 ACRS.
16 So the safety evaluation focuses on 17 normally three, and this time four, main areas. The 18 first area was ensuring the experimental data 19 supporting the model is appropriate. This is a data-20 driven model. It's only as good as the experimental 21 data that is used to generate it.
22 The second was ensuring the model is 23 physically and mathematically appropriate. Here you 24 are just basically looking at, hey, does the form of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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10 it make sense mathematically? Am I going to see any 1
areas where it divides by zero, or is it well-behaved?
2 3
And third is ensuring that the model has 4
sufficient validation. These models live and die by 5
how well they can predict experiment, and so we've put 6
a lot of emphasis on ensuring that this correlation 7
form can predict the experimental data because that's 8
ultimately the reason why we trust it.
9 The fourth was whether Optima-2 issues 10 that occurred at KKL were related to the D5 11 correlation at all and critical power in general, and 12 that was I think a good third to potentially half of 13 the safety evaluation. I don't remember the exact 14 numbers. That's not normally a consideration, but 15 that is, again, why we had all of this attention.
16 Next slide?
17 For our review process, we used criteria 18 that we have used for multiple reviews. We kind of 19 formalized this critical starting -- it was starting 20 a couple of years ago, but we have been working on 21 this safety evaluation for so long that we formalized 22 that stuff in a NUREG, but we actually don't reference 23 this NUREG in this SE because we had the SE written 24 before the NUREG came out.
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11 It's a very formalized framework. It is 1
very structured. It is basically saying if you have 2
a data-driven model, here is all of the things you 3
need to consider. And we just kind of go it piece by 4
piece and say, okay, yes, you've met this, you've met 5
this, you've met this, you've met this, maybe as if 6
you've met all of these things, then your data-driven 7
model is appropriate.
8 MEMBER REMPE: I'm going to stop you 9
because if Jose were here I'm sure he would do it, 10 too. We were impressed with the criteria, for the 11 members who weren't at the subcommittee meeting during 12 our NuScale review, and we had suggested even in our 13 letter report but during the topic when we were 14 discussing it we emphasized, oh, this ought to be 15 documented. These are always in proprietary reports, 16 and it would make it much easier to facilitate the 17 review process.
18 And so we were very happy during the 19 subcommittee meeting, especially Jose, to see that you 20 had indeed followed through on that suggestion, 21 because it wasn't a formal recommendation, but it was 22 in our letter report.
23 MR. KAIZER: Okay. Next slide?
24 Finally, and this is the last slide for 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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12 our open session, our overall conclusions, we reviewed 1
the D5 model with the criteria that we have previously 2
used. We found everything satisfactory.
3 There were a few minor issues as there are 4
in every review. Things are never exactly as they 5
should be, but we were able to resolve all of these 6
minor issues, most of them just having a very good 7
demonstration that, yes, we can show that this doesn't 8
really matter.
9 And, finally, we were able to conclude, 10 and I'd say this was the last bullet we were able to 11 write. And it took a very long time to get there, but 12 we did conclude that there is reasonable assurance 13 that the degradation observed at KKL did not result 14 from an error in the D5 model.
15 Thank you.
16 MEMBER REMPE: Okay. So with that, I'm 17 going to first ask Jose if he wants to add anything in 18 the open session.
19 MEMBER MARCH-LEUBA: No. I think we'll 20 just --
21 MEMBER REMPE: Okay. So --
22 MEMBER MARCH-LEUBA: -- go into closed.
23 MEMBER REMPE: Okay. Then let's go ahead 24 and open the line, and we'll ask the audience, first, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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13 while we're waiting for the public to become 1
available, if she'd like to make a comment, since 2
there's only one person out there. I guess not.
3 So we'll wait and give the public an 4
opportunity to make a comment before we go to closed 5
session.
6 (Pause.)
7 MEMBER REMPE: So with that, we're going 8
to close the open session, which I think I need to hit 9
the gavel for, right? And we're going to switch to a 10 closed meeting, and we'll ask everyone in the room who 11 is authorized to make sure there is no one here that 12 shouldn't be.
13 (Whereupon, the above-entitled matter went 14 off the record at 8:41 a.m. and resumed at 12:37 p.m.)
15 CHAIRMAN RICCARDELLA: Let's get started.
16 The meeting will be regarding the NuScale 17 applicability of the AREVA method for evaluation of 18 fuel assembly structural response to externally 19 applied forces.
20 And I turn the meeting over to Walt. Do 21 you want to initiate the meeting, or Ron? I don't --
22 MEMBER KIRCHNER: I think -- Ron, do you 23 want to take over? And I have no formal comments to 24 make, other than --
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14 MEMBER BALLINGER: The Fuels Materials 1
Subcommittee or people from that, and the NuScale 2
Subcommittee, met and had presentations of this 3
topical report in our August 20th -- I was just going 4
to say August subcommittee. And the presentation that 5
they are going to give today is, obviously, a 6
derivative of that.
7 And in addition to that, we asked them to 8
unpack a few of their seismic numbers for us, which 9
will be done in closed session. But who is doing the 10
-- is it -- Matt, you're doing the presentation, or --
11 MR. PRESSON: Yes.
12 MEMBER BALLINGER: So you're on.
13 MR. PRESSON: All right. Well, thank you, 14 and good afternoon. I am Matthew Presson, licensing 15 specialist with NuScale Power, project manager for 16 this topical report. We are here today to discuss the 17 applicability of the AREVA method for the evaluation 18 of fuel assembly structural response to externally 19 applied forces.
20 Presenting today will be primarily Brett 21 Matthews, Framatome technical lead for the NuScale 22 fuel design project, supported by myself and 23 licensing, and Larry Linik in fuels engineering, who 24 may be joining us over the phone.
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15 And with that, I will go ahead and pass 1
the presentation over to Brett.
2 MR. MATTHEWS: All right. So let me start 3
with the agenda, and I won't spend a lot of time here.
4 I'm going to spend a lot of time in the presentation 5
providing the necessary background for us to talk 6
about the applicability of the method, starting with 7
an overview of Framatome's topical ANP-10337. This 8
was the subject of an ACRS meeting about a year and a 9
half back in early 2018.
10 We'll talk about the scope of generic 11 applicability for that, provide an overview of the 12 NuScale fuel design, which we refer to by its trade 13 name here, NuFuel-HPT2, and then talk about the 14 process that we use to assess applicability, and then 15 the conclusions from that study.
16 So if we go to the next slide, we'll jump 17 into an overview of ANP-10337. The fundamental focus 18 of this methodology is the evaluation of fuel safety 19 functions during earthquakes and pipe breaks. It's 20 the fuel assembly response, structural response, to 21 external loads, so motions from loss of coolant 22 accident or seismic event.
23 And we're looking at a PDF here, but this 24 cartoon represents a seven-assembly row taken from the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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16 NuScale analysis that we did. If we were running this 1
in PowerPoint, there is actually an animation to show 2
how that simulation plays out. But I'll stop and 3
point out a couple of things in this cartoon that we 4
can refer back to as we move through the presentation.
5 The first thing that I want to show --
6 again, this is representing seven fuel assemblies 7
across the longest row, but I'll draw your attention 8
to the small maroon I guess it is, maroon rectangles 9
on each fuel assembly. These are representing the 10 intermediate spacer grids on the fuel assembly. And 11 spacer grids have a lot of functions, but for what 12 we're talking about today it serves a very important 13 function in that transmits any impact loads between 14 the fuel assemblies.
15 So as these fuel assemblies are 16 oscillating back and forth under external motion, the 17 fuel is designed such that all contact occurs at those 18 spacer grid locations, and only at those spacer grid 19 locations. So those spacer grids have to be designed 20 to be able to take that load and transfer it down the 21 line.
22 The other thing that you would see if we 23 were running this simulation is you would see how the 24 fuel assemblies kind of sway back and forth in 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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17 response to the seismic event. And primarily what you 1
would see is the fuel assemblies oscillating with kind 2
of a C-shaped bow back and forth. That C-shaped bow 3
corresponds to the first mode, frequency response of 4
the fuel, which makes sense because we are simulating 5
a seismic event, which relative to the fuel it's a 6
relatively low frequency event. It's primarily going 7
to excite the fuel in that first mode frequency range.
8 So what we get out of the simulation, the 9
big things that we're looking at are the impact loads 10 between the fuel assemblies and between the fuel 11 assembly and the baffle plate or reflector, and also 12 the stresses in the fuel assemblies, as a result of 13 not only the impact loads but the deflection shapes 14 that the fuel takes as it's moving back and forth. So 15 we pay close attention to those deflection shapes as 16 well.
17 So let me move to slide 5. I always like 18 to start with defining kind of the regulatory 19 framework that we're working within, and for this 20 generic topical, 10337, the main components of this 21 regulatory framework are 10 CFR Part 50, Appendix A, 22 which defines the generic design criteria.
23 There are a handful of those that are 24 relevant to what we are working towards: 10 CFR Part 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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18 50, Appendix S, which addresses earthquake engineering 1
or the safety functionality to withstand earthquakes; 2
10 CFR 50.46, which of course addresses the 3
requirements to be met following a LOCA event pipe 4
break; and then the relevant regulatory guidance in 5
this case comes from the standard review plan, Chapter 6
4.2, Appendix A.
7 Appendix A is really focused on this 8
evaluation of the fuel assembly response to external 9
loads. But if we take this framework and kind of boil 10 it down in layman's terms, really, it comes down to 11 three criteria that we set out to satisfy in this 12 evaluation, and that is maintaining coolable geometry 13 in the fuel assembly, maintaining a path for control 14 rod insertion to insure safe shutdown, and then fuel 15 rod integrity, which is both a coolability concern if 16 there is fragmentation of the fuel rod, but also 17 maintaining that barrier -- first barrier to fissile 18 material.
19 So slide 6, continuing on with the 20 overview, I put this slide in just to give kind of a 21 visual of what we do as part of the core part of this 22 analysis. This analysis is run with what we call time 23 history inputs at the core boundaries, and these are 24 the excitation. These are the external loads that we 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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19 use to excite the fuel.
1 What we refer to here as time history 2
inputs are really the core motion history of the core 3
plates, which are the boundaries, fixed boundaries at 4
the top and bottom of the fuel assembly, as well as 5
the motion of the baffle plates or the reflector, 6
since that is also potentially a boundary that the 7
fuel assembly can come into contact with.
8 Now, these time history inputs are derived 9
from upstream models of the reactor vessel internals.
10 In fact, the analysis that we are doing here is 11 actually at the end of a long line of analyses that is 12 performed, and starting from the definition of the 13 seismic ground motion that we need to be concerned 14 with, the definition of soil structure interaction and 15 how that is propagated to a building structure, how it 16 propagates through the building structure into the 17 reactor, through the reactor vessel internals, and 18 then finally we get to the heart of the reactor, and 19 here we're analyzing the response of the core to those 20 motions.
21 But, again, we are at the end of a very 22 long line of analyses, and there is a lot of 23 uncertainty and conservatism that builds up as we get 24 down to that core analysis.
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20 Now, before we depart this slide, the 1
other thing that I wanted to point out is I have put 2
a couple of schematics on here -- again, another 3
important visual to take away -- and there are two 4
points to be made here. First of all, you'll notice 5
that there is a lateral schematic and a vertical 6
schematic.
7 So one of the unique things that we do in 8
this analysis is we analyze the motion of the fuel or 9
the response of the fuel in three independent 10 orthogonal directions. So we'll run an analysis in 11 the X, Z, and Y direction independently. And then at 12 the back end of the analysis we will pull those 13 components together to come up with a three-14 dimensional load state.
15 The other thing that I want to point out 16 here is that when you pull back the skin from these 17 models, and you're looking at the skeleton, what we're 18 left with is really a relatively -- or within the 19 world of mechanical engineering it's a fairly basic 20 structural representation of the fuel, where we are 21 using basic elements, themes, and springs, and 22 dampers, and gap elements, to represent the structural 23 response of the fuel.
24 So continuing on with that thought, on 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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21 slide 7 --
1 CHAIRMAN RICCARDELLA: But the lateral 2
schematic is basically a two-dimensional model, right, 3
that you're running?
4 MR. MATTHEWS: It is a two-dimensional 5
model, but we will run a row analysis in the X 6
direction and then we will run a separate row analysis 7
in the Z direction.
8 CHAIRMAN RICCARDELLA: And are they two 9
different models in the --
10 MR. MATTHEWS: It's the same model.
11 CHAIRMAN RICCARDELLA: Same model but two 12 different inputs.
13 MR. MATTHEWS: Yes.
14 CHAIRMAN RICCARDELLA: Yeah. Got it.
15 MR. MATTHEWS: Okay. So building on that 16 schematic representation, the point that I wanted to 17 make there is that the fuel is represented using 18 simple and generic structural models. And this is 19 something we are going to draw on when we talk about 20 the applicability of what we do in this method.
21 Even though there can be a lot of detail 22 in terms of fuel assembly structure, in terms of 23 individual fuel rod connections, the number of guide 24 tubes, we boil that down into a homogenous beam 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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22 structure. So we really don't care if it's a 14 by 1
14, or a 17 by 17, number of guide tubes, all of that 2
gets homogenized into a relatively simple and generic 3
structural representation.
4 What's really important in this model is 5
how we define the numbers to define all of those 6
elements of the model, and so I want to talk for a 7
minute about how we go about defining those model 8
parameters.
9 And there are really three different 10 sources for the definition of these model parameters.
11 The first really encompasses most of the parameters in 12 the model, and it's the simplest. These are 13 parameters that are based directly on information from 14 design documents, such as engineering drawings, 15 material specifications.
16 So this would be information, geometric 17 information -- outer diameter of a tube, inner 18 diameter, material properties like Young's modulus.
19 These are things that we can read directly from 20 engineering specifications and put into the model.
21 The second category of model parameters 22 are slightly more complex in that they can't be read 23 directly off of a design document. These are 24 parameters where we rely on design-specific 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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23 characterization testing. So, conceptually, what we 1
are characterizing is fairly simple, but it would be 2
things like the lateral stiffness of the bundle or the 3
frequency response of the bundle. These are things 4
you can't get off of the drawing, but we can 5
interrogate a prototypic test assembly to easily 6
process that information.
7 So ANP-10337 defines a
full 8
characterization protocol, full suite of tests that is 9
necessary to define all of these parameters to fully 10 populate the model.
I will note that full 11 characterization protocol was applied to NuScale, and 12 I'll stop and pause here and mention also that there 13 was an NRC audit performed during part of that testing 14 as well. NRC was able to come out to our Horn Rapids 15 Road facility in Richland, Washington, and observe 16 some of that testing being performed on a prototypic 17 NuScale assembly.
18 Now, the third and last category, there 19 are three parameters that account for fluid effects, 20 and this is the one area in the methodology where we 21 have parameters that are defined independent of the 22 design. And these fluid effects are added mass, the 23 coupling mass, and fluid damping.
24 So there is a little bit of foreshadowing 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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24 in the presentation here, but this is obviously 1
something that we are going to reflect back on to talk 2
about when we start talking about the applicability of 3
these methods to NuScale. This is an obvious one that 4
we have to challenge.
5 The key takeaway here, though, is aside 6
from the fluid effects, the modeling is largely 7
transparent to the fuel design. It is set up to be 8
generically applied to a wide range of fuel assembly 9
types.
10 CHAIRMAN RICCARDELLA: Can I go back to 11 the previous slide? Those -- you have all of those 12 different spring and dashpot elements that I presume 13 each one of those represents a spacer grid?
14 MR. MATTHEWS: That's correct.
15 CHAIRMAN RICCARDELLA: And are the springs 16 and -- are they different as you go up that vertical 17 column, or are they all the same? The spring 18 constants, for example.
19 MR. MATTHEWS: In this case, they are all 20 the same. They would be all the same because the 21 spacer grid is the same -- that is true. So we're 22 going to get to that in a future slide, so the bottom 23
-- it is true, the lower spacer grid is a different 24 type.
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25 CHAIRMAN RICCARDELLA: Okay. Gotcha.
1 MR. MATTHEWS: But it is not represented 2
in these models, and I'll talk to that.
3 CHAIRMAN RICCARDELLA: But now if this --
4 you say transparency with regard to fuel designs. For 5
a conventional reactor in which it's much -- the fuel 6
is much longer, would I -- I presume you'd have more 7
of these little spring --
8 MR. MATTHEWS: Yes.
9 CHAIRMAN RICCARDELLA: -- dash elements to 10 make a taller -- a taller fuel bundle?
11 MR. MATTHEWS: That's correct.
12 CHAIRMAN RICCARDELLA: Okay.
13 MR. MATTHEWS: So that's another point 14 that I'm going to -- that's a key point that we have 15 to discuss, and, you know, if we go back -- if you 16 don't mind backing up to slide 4 real quick. I'll 17 just do this very briefly.
18 So, again, this is -- it's a cartoon 19 representation taken directly from a
NuScale 20 simulation, but you'll notice here there are only 21 three spacer grids being represented in this model.
22 That's something we'll talk about, the meaning of that 23 and the significance of that in terms of, is that an 24 adequate representation of the fuel?
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26 MEMBER CORRADINI: Since I wasn't at the 1
meeting, just to clarify, so there are more than three 2
for thermal hydraulic purposes, but for structural 3
support for this external response, we are looking at 4
three.
5 MR. MATTHEWS: Yes.
6 MEMBER CORRADINI: Okay. Fine.
7 CHAIRMAN RICCARDELLA: I guess I don't 8
understand. The schematic that you -- the lateral 9
schematic that you showed showed a lot more than 10 three.
11 MR. MATTHEWS: Yeah. And so what's going 12 on here, the schematics, these are from an existing 13 PWR design that would have more spacer grids.
14 CHAIRMAN RICCARDELLA: Okay.
15 MR. MATTHEWS: So, I'm sorry, it is not a 16 one to one.
17 CHAIRMAN RICCARDELLA: Okay.
18 MEMBER CORRADINI: You're showing a 19 cartoon of a full size here.
20 MR. MATTHEWS: Yeah. This is full size.
21 I apologize for the confusion, but this is not 22 NuScale.
23 CHAIRMAN RICCARDELLA: If you showed one 24 of these that was specific to NuScale, it would only 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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27 have three of those things?
1 MR. MATTHEWS: That's correct.
2 CHAIRMAN RICCARDELLA: Okay Got it.
3 MR. MATTHEWS: All right. So I think 4
we're up to slide 8. So continuing that line of 5
thought, though, and talking about the applicability 6
of ANP-10337, the original intent for that topical was 7
for it to be generically applicable to PWR designs.
8 And we say that for a number of reasons.
9 We talked about the modeling -- how the modeling is 10 really simple and generic to where it can be applied 11 to a wide range of assembly types, and we can do that 12 because PWR fuel designs share the same basic 13 construction, thus allowing that same representation.
14 Again, we are not necessarily concerned as 15 to whether we're dealing with a 14 by 14 or a 17 by 17 16 array, or whether we've got five guide tubes or 24, 17 all of that is homogenized into the same simple 18 generic structural representation. It's a pretty 19 versatile representation.
20 The other thing is that PWR operating 21 environments are all very similar similar 22 temperature, similar flow rates -- so it's -- from the 23 fuel assembly perspective, it's hard to tell, you 24 know, the difference between one reactor type and 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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28 another.
1 There was one criteria, however, noted for 2
applicability, and that has to do with modeling 3
assumption to represent the impact behavior of the 4
spacer grid. So on one of the previous slides we 5
zeroed in on the little assembly of springs and 6
dampers representing the impact element at the spacer 7
grid locations.
8 There is a lot of nuance that goes into 9
modeling that. Again, since that is the element that 10 is transmitting all of the energy in the core, and 11 taking the impact load, things can get to be slightly 12 more complicated when we start to talk about the 13 accumulation of deformation in that element, and when 14 we start introducing plastic deformations.
15 So there is a modeling assumption to 16 represent that impact behavior in ANP-10337. I will 17 note that in the case of NuScale, we're using the 18 exact same spacer grid that we demonstrate in ANP-19 10337 sample problem. It's the exact same geometry, 20 same hardware. We've just put it on a shorter fuel 21 assembly. So we're applying the same -- we're working 22 within the same range of applicability for NuScale.
23 Final point here regarding applicability.
24 There were limitations and conditions imposed through 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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29 the SER, and I guess we'll jump ahead a slide to 1
slide 9. We can walk through those.
2 We were requested in RAI 9555 to address 3
all of these L&Cs, and I will briefly walk through 4
them here. I do want to say I'm -- I've got text here 5
to describe what the L&Cs are about. I'm just 6
paraphrasing. This is not the exact language, but --
7 so starting with items 1 and 2, I'm going to lump 8
those together because those L&Cs have to do with, 9
one, demonstrating critical grid behavior in our 10 impact test protocol; and, number two, a limit on the 11 maximum allowable spacer grid deformation.
12 Much like we said on the previous slide, 13 we're using the exact same component, in this case the 14 same spacer grid that we demonstrated in the sample 15 problem, so we're meeting those L&Cs for NuScale in 16 the same way that we do in the base topical.
17 Number three refers to defining controls 18 and quality requirements on the engineering software 19 that we use to implement this topical. We use an 20 internal finite element code called CASAC that is 21 proprietary to Framatome. But, again, we are using the 22 same software in the application of NuScale that we do 23 in the sample problem or that we define in the 24 topical. So there is no difference there.
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30 L&C number 4 limits the use of the 1
applications consistent with the operating fleet. So 2
when we were reviewing this with the NRC and we talk 3
about generic applicability, I think we were all on 4
the same page in terms of accepting that. But there 5
was -- the NRC was, you know, alert to the fact that 6
this is a true statement for existing PWRs, but we 7
don't have a crystal ball. We don't know what the 8
next generation of reactor is going to look like, what 9
that environment is going to be like.
10 So this is an L&C to address that, to make 11 sure that as we extend to things like NuScale that we 12 stop and address the applicability of this method. So 13 I highlighted that because, frankly, this is why we're 14 here today, to discuss that L&C.
15 L&C number 5 limits the applicability of 16 the lateral damping values to existing fuel designs.
17 Again, we talked about this on a previous slide as 18 well, that in the base topical we define those values 19 independent of fuel designs. And, again, we were 20 willing to accept that definition to existing designs 21 as we know them today, but moving forward, for the 22 next generation of fuel designs, it's something that 23 needs to be questioned.
24 So, again, this comes into play with 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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31 NuScale, and that's something that we're going to 1
address in this applicability topical.
2 Number 6 requires a fuel rod stress 3
assessment under faulted conditions. This is something 4
that is not described in detail in ANP-10337, so this 5
is just a catch to make sure that we are executing 6
that evaluation. We do that for NuScale in the same 7
way that we do in the sample problem for 10337.
8 Number 7, this one requires the use of the 9
most limiting stress criteria when a bounding analysis 10 is performed for both rodded and non-rodded locations.
11 What this is boiling down to is making sure that we're 12 using the most limiting criteria on the guide tubes to 13 make sure that we're ensuring control rod 14 insertability. And, again, we do that for NuScale.
15 L&C number 8 specifies that a 3-D 16 combination of loads should be considered for non-grid 17 components. This is another one that we have already 18 talked about in the way that we run these analyses in 19 three directions. We then recombine that into a 20 three-dimensional state, so we're complying with that 21 for NuScale.
22 And then number -- I'm sorry.
23 CHAIRMAN RICCARDELLA: SRSS, is that how 24 you combine?
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32 MR. MATTHEWS: Yes. It's SRSS.
1 And then, number 9, this is similar to 2
number 1 and number 2 in that it's another limitation 3
on the applicability of the spacer grid impact 4
modeling. Again, our response for that is very 5
similar to what we say for number 1 and 2. We're 6
using the same spacer grid, so we're applying the same 7
range of applicability as demonstrated in the sample 8
problem to the base topical.
9 All right. So if we can move forward to 10 number -- slide 10. So that summarizes what I wanted 11 to say in terms of the review of ANP-10337, kind of 12 build that foundation to start working with in this 13 presentation. I'm going to shift gears now and talk 14 a little bit for the next couple of slides about the 15 NuScale design and the NuScale fuel design.
16 So, again, the NuScale fuel design --
17 trade name is NuFuel-HTP2 -- this design is based on 18 Framatome's existing 17 by 17 PWR technology. So the 19 graphic that we have on the right side of the screen 20 here, if we were to take a cross-section slice of that 21 assembly at any location above the bottom nozzle 22 assembly, you would not be able to distinguish this 23 from our existing 17 by 17 designs.
24 It's the exact same geometry, same rod 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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33 geometry. Spacer grids are same components from the 1
existing 17 by 17 PWR technology, and that's important 2
for a number of reasons. One thing that I want to 3
pause and talk about here is, you know, on a previous 4
slide we talked about how fluid effects are defined 5
independent of design. Two of those were the added 6
mass effect and the coupling mass effect.
7 If you look at how those values are 8
derived in ANP-10337, they are derived based on the 2-9 D cross-sectional effects in the assembly. And so if 10 we were to extend that exercise to NuScale, we would 11 be repeating the exact same exercise that we have 12 already done in 10337.
13 So all of that to say that at least of 14 those two fluid effects, the added mass and the 15 coupling mass, we would arrive at the same answer for 16 NuScale. And those values, as they're defined in 17 10337, continue to be applicable to the NuScale fuel 18 design because we have that exact same cross-sectional 19 makeup.
20 And where the differences are in the 21 NuScale design are in the axial layout, obviously.
22 This is a shorter assembly, and we have already 23 touched on this. But this fuel design has a total of 24 five spacer grids.
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34 The lowest-most spacer grid design, as was 1
noted earlier, it is unique from the others. Although 2
it is not unique relative to our existing 17 by 17 3
design, we used the same HMP -- Iconel 718 HMP spacer 4
at that lower grid location on those designs as well.
5 So we have an Inconel 718 HMP at the 6
lowermost location, and then the other four spacer 7
grids are a Zirc-4 HTP grid type. So, again, we count 8
the grids, we've got five grids. We represent three 9
of those in our structural modeling.
10 The reason we do that is because ANP-10337 11 looks at the uppermost and lowermost grids, which in 12 this case I don't have the exact dimensions. I know 13 we talked about it in the subcommittee meeting, but 14 the spacer grids are about two inches away from the 15 top and bottom nozzle. They are very close to that 16 end condition.
17 ANP-10337 says that those spacer grids are 18 so close to those fixed end conditions that they don't 19 really have an opportunity to participate much in the 20 dynamic response of the fuel assembly. So what we do 21 is we make a simplification, a modeling assumption, 22 that those end grids get rolled into the fixed end 23 conditions at the top and bottom.
24 And we only look at rotational degree of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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35 freedom at those intermediate spacer grids, which in 1
this case leaves us with three intermediate rotational 2
degrees of freedom in the assembly.
3 So this is something, again, that we are 4
going to talk about, is that adequate to capture the 5
dynamic response to the fuel assembly? We put some 6
effort into analyzing that and challenging that to 7
make sure that this is adequate.
8 The other features I won't go into detail, 9
but the guide tubes, the quick disconnect, Alloy M5 10 fuel rod cladding, all of these are also borrowed from 11 our existing 17 by 17 fuel assembly designs.
12 All right. So if you will advance to 13 slide 11. So continuing the discussion of how the new 14 fuel HTP2 fuel design compares with existing Framatome 15 17 by 17 designs, this is presenting a lot of similar 16
-- the same information that we talked about on the 17 previous slide, just comparing key dimensions and 18 features.
19 As you can see, intentionally there are a 20 lot of numbers that are the same in both columns. And 21 if you were to kind of parse these out, what you're 22 seeing is that the numbers having to do with the 23 cross-sectional properties are exactly the same. They 24 are identical. Again, the only difference is in the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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36 axial layout of this fuel design.
1 And so I've highlighted in blue the key 2
differences, number 1 being the fuel assembly height.
3 We're a little more than half the height of the 4
existing 17 by 17 design. And, again, that begs the 5
question is -- are our methods -- with that shorter 6
assembly, are our methods adequate to capture the 7
dynamic response of the shorter assembly?
8 The grid span length is a little bit 9
different. It's within a couple of percent of the 17 10 by 17 design at 20.1 inches. However, outside of our 11 experience with 17 by 17s, it's well within the 12 experience for all of our PWR designs. It's bounded, 13 both on the upper and lower ends.
14 This is a value, too, that gets modeled 15 directly. When we place the spacer grids in that 16 structural model, this 20.1 inches is reflected 17 directly of course.
18 If we advance to slide 12, one more item 19 in talking about how NuScale compares to existing 17 20 by 17 designs, we can compare the operating parameters 21 for NuScale with the typical operating -- typical 22 operating values for existing 17 by 17 designs.
23 This chart is a little more interesting 24 than the last one because there are a lot more 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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37 differences in the numbers. However, most of these 1
numbers are really inconsequential for what we are 2
looking at in terms of looking at the structural 3
response of the fuel to external dynamic excitation.
4 So things like thermal power. Pressure is really of 5
secondary importance. A lot of these don't have any 6
consequence on the simulations that we're running.
7 Core temperature is taken into account 8
directly. So we scale the models to the appropriate 9
core temperature for NuScale. That is reflected 10 directly.
11 What is of interest in this table and what 12 is of relevance and significance to us is what I've 13 highlighted in blue, which is showing that the NuScale 14 design operates at a much lower -- with a much lower 15 flow
- rate, lower coolant velocity.
- And, 16 correspondingly, you see that in the Reynolds number 17 as well.
18 So this gets back to what we talked about 19 earlier and having to challenge those fluid effects, 20 in particular the damping that is associated with 21 these different environments. So that's something we 22 have to tackle for NuScale.
23 All right. So advance to slide 13, please.
24 So now that we've got an understanding, at 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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38 least high level, of how NuScale, both the fuel and 1
the operating environment, compares with existing 2
PWRs, we can start to talk about assessing the 3
applicability.
4 And just real briefly, the process that we 5
applied in assessing applicability, we first off 6
started with the regulatory framework. I always like 7
to start there to make sure that we're in the same 8
design space. We're working with the same framework.
9 NuScale is working within the same regulatory 10 framework as ANP-10337. So we're blowing everything 11 down to the same concerns. We need to satisfy 12 coolable geometry, control rod insertability, and fuel 13 rod integrity.
14 Number two is we performed a comparison of 15 the parameters that are important to the seismic LOCA 16 response, which we just did on the previous three 17 slides. And when we do that, there are three big 18 things that jump out at us as being significant -- the 19 shorter fuel assembly length of the new fuel HTP2 20 design, the fact that as a result of that shorter 21 length we have fewer spacer grids that get represented 22 in the model, and then also the difference in coolant 23 flow.
24 And then taking those differences forward, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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39 we applied to a detailed review of the ANP-10337 1
content, including the L&Cs. And if you read the 2
applicability topical, it is literally structured 3
around this process. It is structured around a 4
chapter-by-chapter review of ANP-10337 with 5
consideration to those differences.
6 All right. Slide 14?
7 So that was the process, and I'm going to 8
jump straight to the conclusion, what fell out of that 9
process. There were three relevant points that came 10 out of our evaluation. Number one is a question that 11 we have hinted at throughout this presentation, which 12 is, does the model architecture and characterization 13 testing protocol from ANP-10337 adequately represent 14 the NuScale fuel design with its shorter length and 15 fewer spacer grids? And the answer that we arrive at 16 going through all of this is that, yes, it does. We 17 can adequately represent that without any 18 modifications to the existing method.
19 In short, the reason that we arrive at 20 that conclusion is because we have been able to show 21 that applying the techniques and the protocol direct 22 from 10337, we still arrive at a place where we are 23 accurately capturing the dynamic response of the fuel 24 that is of interest, what we're trying to simulate.
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40 So issue number 2 is that ANP-10337 PA 1
establishes lateral fuel assembly damping parameters 2
that credit flow rates, that are typical for existing 3
PWRs. The question there is, are these values valid 4
in the NuScale design? And the answer that we arrived 5
at is that, no, they are not.
6 The reason we arrived at that is because 7
ANP-10337 defines damping values that are constructed 8
with three components. There is a structural damping 9
component, which is really the -- it's the level of 10 damping that you would observe just from the fuel 11 assembly oscillating in air. So this is something 12 that we get directly from the characterization tests 13 that we do when we perform pluck tests and force 14 vibration tests. You can measure that directly.
15 The second component is a component of 16 damping that is going to be present just given the 17 fact that this fuel assembly is trying to oscillate in 18 a dense medium. It's trying to push through this 19 dense coolant.
20 And then the third component is also 21 related to the fluid, but it's specific to the fact 22 that not only is it oscillating in this dense fluid, 23 but as it deflects laterally it is deflecting into 24 oncoming traffic with flow rushing past it. So as it 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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41 pushes out, there is going to be a restorative force 1
from the flow rushing past trying to push it back to 2
its neutral plane.
3 CHAIRMAN RICCARDELLA: So you'd expect as 4
the flow goes up, the damping goes up.
5 MR. MATTHEWS: Yes. So that final piece 6
is what is not present. Well, it is present, but in 7
a much smaller magnitude for NuScale. So given that, 8
we redefine damping for the NuScale application. And 9
where we ended up with, because we threw out that 10 third component, we end up with a value that is lower 11 than what is defined in 10337.
12 From the standpoint of running a
13 simulation, that's moving in the direction of 14 conservativism because we're eliminating damping from 15 the system. We're removing a key source of energy 16 dissipation.
17 The third issue is that RAI 9225 questions 18 the need for the evaluation of the fuel during 19 refueling, specifically while it's stored in the 20 reactor flange tool. And where we arrive at on this 21 issue when we looked into it is that we reached the 22 conclusion that to definitively address the issue, we 23 needed to perform an additional analysis above and 24 beyond what you would get from reading ANP-10337.
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42 So we continue to leverage that 1
methodology for this additional analysis when the fuel 2
was in the RFT.
3 Okay. So moving to slide 15, that brings 4
me to the conclusions, where we ended up. So 5
ANP-10337 PA defines a methodology that continues to 6
be applicable to NuScale with two modifications.
7 The first is that we have to redefine fuel 8
assembly damping to be specific to the NuScale 9
application, and the second item is really in addition 10 to what is defined in 10337, we perform an additional 11 seismic evaluation in which the core is residing in 12 that reactor flange tool.
13 And that's it.
14 MEMBER BALLINGER: Questions? I think we 15 should just change out with the -- well, actually, I 16 shouldn't say this, we are three minutes ahead of 17 schedule. Thank you.
18 So if the staff ready to go?
19 CHAIRMAN RICCARDELLA: So are we going to 20 talk -- we're going to talk more about this in closed 21 session?
22 MEMBER BALLINGER: Yeah.
23 CHAIRMAN RICCARDELLA: All right.
24 (Pause.)
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43 MEMBER BALLINGER: Yes. So, Chris, it 1
looks like you're on the hook.
2 MR. VAN WERT: Well, I actually have Nick 3
calling in from PNNL, so get him a life line open.
4 MEMBER BALLINGER: Go ahead when you're 5
ready.
6 MR. BAVOL: Okay. Good afternoon. My 7
name is Bruce Bavol. I'm a project manager for the 8
new reactors, NRC.
9 The technical reviewer lead for this 10 particular topical report is Chris Van Wert, to my 11 right, and on the bridge line, Nick Klymyshyn, from 12 Pacific Northwest National Labs.
13 The staff timeline for this review, I 14 provided two references, the first two bullets, and 15 from here, from the full committee, we will be 16 planning to issue the final safety evaluation in late 17 October, and the dash A or approved version we expect 18 to be early 2020 for administrative purposes.
19 With that, I will turn it over to Chris 20 for staff review.
21 MR. VAN WERT: All right. Thank you.
22 So before we kind of dive into the slides 23 here, I want to just try and describe what the scope 24 of the staff's review included and what was outside of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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44 the scope of this review.
1 So, in particular, the review included an 2
evaluation of the NuScale fuel design versus the 3
reference methodology topical report that we just 4
heard about, 10337. And by that, I mean, we looked at 5
the fuel assembly versus the assemblies that were used 6
in 10337, and looked at the differences.
7 We also evaluated their presentation of 8
the limitations of conditions and how those were 9
addressed for the NuScale design. Additionally, the 10 staff's review included any modifications to the 11 reference methodology.
12 The review did not include the underlying 13 methodology itself. As is expected, that was covered 14 under the staff's review of ANP-10337. And it also 15 does not cover the actual application of the 16 methodology to review the NuScale fuel design. That 17 is captured under tech report -- as the number is 18 listed there below, that is captured in the staff's 19 review in Chapter 4 of the NuScale DCD -- or DCA.
20 So this is pretty much parroting back what 21 you've just heard from Brett, but in general, a quick 22 summary of 10337 is that it presents a generic 23 methodology that is applicable to PWR fuel assemblies 24 and the structural response. It considers things such 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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45 as irritation effects. It provides a protocol for 1
benchmark testing. It defines the acceptance criteria 2
and a few other things listed here.
3 It is used for demonstrating compliance 4
with GDC 2, 10 CFR 50 Appendix S. And as mentioned 5
before as well, it does follow generally the guidance 6
provided in SRP 4.2 Appendix A. And it does contain 7
nine conditions and limitations, which anyone 8
referencing that methodology must demonstrate that 9
they meet.
10 And, again, this is a quick summary for 11 the fuel design itself. It is very similar to the 12 operating fleet, 17 by 17 Framatome fuel design, M5 13 pins, Zirc-4 guide tubes, HTP grids, HMP bottom grids.
14 The key differences are related to height, so there's 15 half-height, and that results in fewer grids, in this 16 case five versus seven total number of grids.
17 So in terms of modifications to the 18 methodology, most of them are in relation to the axial 19 height. They are half length and fewer grids, so the 20 model itself had to be changed in order to reflect 21 that. And the staff looked at those modifications and 22 determined that it was consistent with the general 23 methodology and was acceptable.
24 One other key one that was mentioned just 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
46 a second ago was related to axial coolant flow. And 1
as you heard, it is much -- it is significantly slower 2
for NuScale, so that one -- that component of the flow 3
damping was damping was ignored.
It's a
4 conservative assumption, although it's not a very 5
appreciable one.
6 But beyond that, they did specific testing 7
of the NuScale fuel assembly in the conditions to 8
determine their value. So it does differ from the 9
ANP-10337 value.
10 The last one is kind of included just to 11
-- I don't know if it's creates more confusion or 12 alleviates it. But in the SE, we talk a little bit 13 about the modification in which the mode shapes that 14 are assumed, both in the -- that are characterized 15 versus that are assumed in the modeling, that there is 16 this difference, that the modeling only uses three but 17 the methodology says that you are supposed to use 18 five.
19 At the time we did the review, ANP-10337 20 did have that requirement that you characterized the 21 first five mode shapes. We wrote that part up, and 22 then after the dash A's came out we realized that 23 10337 was modified at the end to reduce it down to 24 only three being needed.
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
47 So, in the end, they are consistent, but 1
I just wanted to bring it up, since that is covered in 2
the staff's SE.
3 And so, again, limitations and conditions 4
are a major part of the staff's review. A lot of 5
these, if we look at, say, number one, it's the grid 6
behavior, that's dispositioned by the fact that it is 7
the same grid used both for NuScale as well as the 8
operating fleet.
9 Similar for the grid deformation 10 applicability limits. Being the same grid, it has the 11 same limits. The same version of the code was used, 12 so limitation condition number 3.
13 As far as 4 goes, yes, this is a different 14 fleet, a different design than the operating fleet.
15 So the staff's review did focus on that. We were 16 looking heavily at the differences between the reactor 17 designs and the fuel designs. And we also relied on 18 their application, the responses to the RAIs, as well 19 as independent confirmatory analyses, which we had 20 PNNL provide for us.
21 Limitation number 5 is related to damping, 22 as we already mentioned, that they do differ, although 23 the method that they use to determine their damping is 24 consistent with 10337.
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
48 And numbers 6, 7, and 8 are actually in 1
relation to how it is applied. And as I alluded to at 2
the beginning of this presentation, the topical report 3
in front of us does not actually provide the analysis.
4 That's covered in the tech report. So our review --
5 we had to look at the tech report, which is still 6
under review, but we did determine from looking at 7
that separate document that they do need 6, 7, and 8 8
here.
9 And number 9, grid deformation model, 10 since it is the same grids, the limit on the impact 11 model is not exceeded.
12 So, in conclusion, the staff concludes 13 that the fuel assembly meets the conditions and 14 limitations as provide within the reference 15 methodology ANP-10337. We also conclude that the 16 modifications to the approved methodology are 17 appropriate for NuScale and are also acceptable.
18 The staff also finds that the use of 10337 19 is acceptable for NuScale, given the modifications as 20 outlined within the topical report.
21 Any questions?
22 MEMBER BALLINGER:
Any questions?
23 Questions? Now we're way ahead of schedule. Thank 24 you.
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
49 Now we need to go to public comment. So 1
are we getting the line -- I guess we should ask if 2
there is anybody in the room that would like to make 3
a comment. Doesn't look like there is too many public 4
here. Is it open?
5 MR. SNODDERLY: Is there anyone on the 6
public line? Is there anybody on the public line that 7
would like to make a comment?
8 MEMBER BALLINGER: It doesn't sound like 9
it, but -- but they're all associated with the -- oh, 10 by -- oh. Oh.
11 Is there anybody on the public line that 12 would like to make a comment? If there is, please 13 state your name and make your comment.
14 MR. SNODDERLY: Hearing no one from the 15 open line wants to comment, we're going to -- we're 16 going to now close the line, and we're going to 17 prepare to go into closed session.
18 MEMBER BALLINGER: So folks that are 19 not --
20 MR. SNODDERLY: Everyone in the room needs 21
-- yeah, that meets the -- who needs to be here.
22 (Whereupon, the above-entitled matter went 23 off the record at 1:23 p.m.)
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-0919-66838 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360-0500 Fax 541.207.3928 www.nuscalepower.com August 29, 2019 Docket No. PROJ0769 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 Titled ACRS NuScale Full Committee Presentation: NuScale Topical Report, NuScale Applicability of AREVA Method for the Evaluation of Fuel Assembly Structural Response to Externally Applied Forces, PM-0919-66837, 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) NuScale Full Committee Meeting open session on September 5, 2019. The materials support NuScales presentation of Topical Report, NuScale Applicability of AREVA Method for the Evaluation of Fuel Assembly Structural Response to Externally Applied Forces.
The enclosure to this letter is the non proprietary version of the presentation titled ACRS NuScale Full Committee Presentation: NuScale Topical Report, NuScale Applicability of AREVA Method for the Evaluation of Fuel Assembly Structural Response to Externally Applied Forces, PM-0919-66837, Revision 0.
This letter makes no regulatory commitments and no revisions to any existing regulatory commitments.
If you have any questions, please contact Matthew Presson at 541-452-7531 or at mpresson@nuscalepower.com.
Sincerely, Zackary W. Rad Director, Regulatory Affairs NuScale Power, LLC Distribution: Robert Taylor, NRC, OWFN-8H12 Michael Snodderly, NRC, OWFN-8H12 Samuel Lee, NRC, OWFN-8H12 Gregory Cranston, NRC, OWFN-8H12 Bruce Bavol, NRC, OWFN-8H12 Michael Dudek, OWFN-8H12
Enclosure:
ACRS NuScale Full Committee Presentation: NuScale Topical Report, NuScale Applicability of AREVA Method for the Evaluation of Fuel Assembly Structural Response to Externally Applied Forces, PM-0919-66837, Revision 0
LO-0919-66838 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 NuScale Full Committee Presentation: NuScale Topical Report, NuScale Applicability of AREVA Method for the Evaluation of Fuel Assembly Structural Response to Externally Applied Forces, PM-0919-66837, Revision 0
Copyright 2019 by NuScale Power, LLC.
Revision: 0 Template #: 0000-21727-F01 R5 NuScale Nonproprietary ACRS Full Committee Presentation NuScale Topical Report September 05, 2019 NuScale Applicability of AREVA Method for the Evaluation of Fuel Assembly Structural Response to Externally Applied Forces OPEN SESSION
Copyright 2019 by NuScale Power, LLC.
Revision: 0 Template #: 0000-21727-F01 R5 Presenters Larry Linik Fuels Engineer Brett Matthews Framatome Technical Lead for NuScale Fuel Design Project
Copyright 2019 by NuScale Power, LLC.
Revision: 0 Template #: 0000-21727-F01 R5 Agenda
- Overview of ANP-10337PA
- Scope of Generic Applicability of ANP-10337PA
- NuFuel-HTP2TM Design Overview
- Process to Assess Applicability to NuScale
- Relevant Points from NuScale Applicability Review
- Conclusions
Copyright 2019 by NuScale Power, LLC.
Revision: 0 Template #: 0000-21727-F01 R5 Overview of ANP-10337PA
- Fundamental Focus: Evaluation of fuel safety functions during earthquakes and pipe breaks.
- Simulations evaluate impact loads at grid locations and stresses in fuel assembly components.
Note: Deflections from this simulation were amplified for this animation.
Copyright 2019 by NuScale Power, LLC.
Revision: 0 Template #: 0000-21727-F01 R5 Overview of ANP-10337PA Regulatory Criteria and Guidance
- 1) Coolable Geometry
- 2) Control Rod Insertability
- 3) Fuel Rod Integrity Regulatory Criteria (10 CFR)
- 10 CFR Part 50.46 Regulatory Guidance
- SRP 4.2, Appendix A
Copyright 2019 by NuScale Power, LLC.
Revision: 0 Template #: 0000-21727-F01 R5 Overview of ANP-10337PA
- Time History inputs at the core boundaries are applied as sources of excitation
- Derived from upstream models of reactor vessel internals Lateral Schematic Vertical Schematic
Copyright 2019 by NuScale Power, LLC.
Revision: 0 Template #: 0000-21727-F01 R5 Overview of ANP-10337PA
- Fuel is represented using simple and generic structural models.
- Model parameters definition:
- Most parameters are based directly on information from design documents (geometry, material properties, etc.)
- Some model parameters are based on design-specific characterization testing
- The full ANP-10337PA characterization protocol has been applied to NuScale
- An NRC audit was performed during part of the NuScale testing
- Parameters accounting for fluid effects (added mass, coupling mass, and fluid damping) are defined independent of design Modeling is Largely Transparent to Fuel Designs
Copyright 2019 by NuScale Power, LLC.
Revision: 0 Template #: 0000-21727-F01 R5 Overview of ANP-10337PA
- Intended to be generically applicable to PWR designs
- PWR fuel designs share the same basic construction, thus allowing a simple, generic, structural representation
- PWR operating environments are all very similar
- One criteria is noted for applicability
- Verification of modeling assumption to represent the impact behavior of spacer grids
- NuScale uses the exact same spacer grid demonstrated in the ANP-10337PA sample problem
- Limitations & Conditions were imposed through the SER and these will be reviewed later Original Applicability
Copyright 2019 by NuScale Power, LLC.
Revision: 0 Template #: 0000-21727-F01 R5 Requests for Additional Information
- RAI 9555 requests that L&Cs from ANP-10337PA be addressed
- The SER for ANP-10337PA imposes nine L&Cs:
- 1: Demonstration of critical grid behavior from dynamic impact testing.
- 2: Limits on maximum allowable spacer grid deformation.
- 3: Defines controls and quality requirements on engineering software used to implement ANP-10337PA.
- 4: Limits use to applications consistent with operating fleet.
- 5: Limits applicability of lateral damping values to existing fuel designs.
- 6: Requires a fuel rod stress assessment under faulted conditions.
- 7: Requires the use of most limiting stress criteria when bounding analyses are performed for rodded and non-rodded core locations.
- 8: Specifies that a 3-D combination of loads should be considered for non-grid components.
- 9: Limitation in applicability of spacer grid impact modeling.
PM-0919-66837 10 Copyright 2019 by NuScale Power, LLC.
Revision: 0 Template #: 0000-21727-F01 R5 NuFuel-HTP2TM Design Overview
- NuFuel-HTP2TM based on Framatomes proven US 17x17 PWR technology
- NuFuel-HTP2TM design features
- Four Zircaloy-4 HTP' upper and intermediate spacer grids
- Inconel 718 HMP' lower spacer grid
- Mesh filter plate on bottom nozzle
- Zircaloy-4 MONOBLOC' guide tubes
- Quick-disconnect top nozzle
- Alloy M5 fuel rod cladding
>>Proven features with US Operating Experience
PM-0919-66837 11 Copyright 2019 by NuScale Power, LLC.
Revision: 0 Template #: 0000-21727-F01 R5 Design Comparison NuFuel-HTP2TM vs Framatome 17x17 Parameter NuFuel-HTP2TM Fuel Design Framatome 17x17 PWR Fuel rod array 17 x 17 17 x 17 Fuel rod pitch (inch) 0.496 0.496 Fuel assembly pitch (inch) 8.466 8.466 Fuel assembly height (inch) 94 160 Spacer grid span length (inch) 20.1 20.6 Number of guide tubes per bundle 24 24 Dashpot region ID (inch) 0.397 0.397 Dashpot region OD (inch) 0.482 0.482 ID above transition (inch) 0.450 0.450 OD above transition (inch) 0.482 0.482 Number of fuel rods per bundle 264 264 Cladding OD (inch) 0.374 0.374 Cladding ID (inch) 0.326 0.326 Length of total active fuel stack (inch) 78.74 144 Fuel pellet OD (inch) 0.3195 0.3195 Fuel pellet theoretical density (%)
96 96
PM-0919-66837 12 Copyright 2019 by NuScale Power, LLC.
Revision: 0 Template #: 0000-21727-F01 R5 Parameter NuScale Design Value Framatome 17x17 PWR Value Rated Thermal Power (MWt) 160 3455 System Pressure (psia) 1850 2280 Core Inlet Temperature (F) 503 547 Core Tave (F) 547 584 Average Coolant Velocity (ft/s) 3.1 16 Core Average Re Number 76,000 468,000 Linear Heat Rate (kW/ft) 2.5 5.5 Fuel Assemblies in Core 37 193 Fuel Assembly Loading (KgU) 249 455 Core Loading (KgU) 9,213 87,815 Nominal Cycle Length (EFPD) 694 520 Maximum Fuel Assembly Discharge Burnup (GWd/mtU)
<50
>50 Operating Parameter Comparison NuScale vs Framatome 17x17
PM-0919-66837 13 Copyright 2019 by NuScale Power, LLC.
Revision: 0 Template #: 0000-21727-F01 R5 Process to Assess Applicability
- 1) Review regulatory criteria for NuScale fuel design
- Same framework as ANP-10337PA
- 2) Comparison of parameters that are important to seismic/LOCA response (NuScale vs. Existing PWRs)
- Fuel Assembly Length
- Number of spacer grids
- Coolant flow
- 3) Detailed review of ANP-10337PA content, including SER L&Cs, with consideration to differences
- The applicability topical is structured around a chapter-by-chapter review of ANP-10337PA
PM-0919-66837 14 Copyright 2019 by NuScale Power, LLC.
Revision: 0 Template #: 0000-21727-F01 R5 Relevant Points from the Review Issue #1: Does the model architecture and characterization testing protocol from ANP-10337PA adequately represent the NuScale fuel design with shorter length and fewer spacer grids?
Yes. No modifications are needed.
Issue #2: ANP-10337PA establishes lateral fuel assembly damping parameters that credit flow rates typical for existing PWRs. Are these values valid in the NuScale design?
No. NuScale-specific damping values are derived.
Issue #3: RAI 9225 questions the need for evaluation of the fuel during refueling, specifically, while it is stored in the Reactor Flange Tool (RFT).
An analysis is performed for the RFT using ANP-10337PA.
PM-0919-66837 15 Copyright 2019 by NuScale Power, LLC.
Revision: 0 Template #: 0000-21727-F01 R5 Conclusions ANP-10337PA defines a methodology that is applicable to NuScale with the following modifications:
- Fuel assembly damping values specific to the NuScale design
- An additional seismic evaluation in which the core is residing in the Reactor Flange Tool (RFT)
PM-0919-66837 16 Copyright 2019 by NuScale Power, LLC.
Revision: 0 Template #: 0000-21727-F01 R5 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 Charlotte Office 2815 Coliseum Centre Drive, Suite 230 Charlotte, NC 28217 980.349.4804 Richland Office 1933 Jadwin Ave., Suite 130 Richland, WA 99354 541.360.0500 Arlington Office 2300 Clarendon Blvd., Suite 1110 Arlington, VA 22201 London Office 1st Floor Portland House Bressenden Place London SW1E 5BH United Kingdom
+44 (0) 2079 321700 http://www.nuscalepower.com Twitter: @NuScale_Power
Presentation to the ACRS Full Committee Staff Review of NuScale Topical Report TR-0716-50351, REVISION 0 NUSCALE APPLICABILITY OF AREVA METHOD FOR THE EVALUATION OF FUEL ASSEMBLY STRUCTURAL RESPONSE TO EXTERNALLY APPLIED FORCES Presenters:
Chris Van Wert - Senior Reactor Systems Engineer, Office of New Reactors Bruce Bavol - Project Manager, Office of New Reactors September 5, 2019 (Open Session)
Non-Proprietary 1
NRC Technical Review Areas/Contributors 2
Non-Proprietary REACTOR SYSTEMS NUCLEAR PERFORMANCE & CODE REVIEW BRANCH / NRO:
ADVANCED REACTOR TECHNICAL BRANCH / NRO:
Chris Van Wert Pacific Northwest National Laboratory (PNNL):
Nicholas Klymyshyn
Staff Review Timeline TR-0716-50351, NUSCALE APPLICABILITY OF AREVA METHOD FOR THE EVALUATION OF FUEL ASSEMBLY STRUCTURAL RESPONSE TO EXTERNALLY APPLIED FORCES NuScale submitted Topical Report (TR)-0716-50351, NuScale Applicability of AREVA Method for the Evaluation of Fuel Assembly Structural Response to Externally Applied Forces, Revision 0, on September 30, 2016, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML16274A469).
NuScale submitted ANP-10337P-A, PWR Fuel Assembly Structural Response to Externally Applied Dynamic Excitations, Revision 0, on April 30, 2018 (ADAMS Accession No. ML18144A816)
Staff plans to issue its final SER in late October 2019.
Staff plans to publish the -A (approved) version of the TR in early 2020.
3 Non-Proprietary
Scope of the Staff Review The staffs review included:
- Evaluation of the NuScale design versus the reference methodology topical report (ANP10337PA)
- Comparison of the NuScale fuel assembly design versus the designs covered by the methodology
- Evaluation of the limitations and conditions
- Evaluation of modifications to the referenced methodology The staffs review did not include:
- The underlying methodology (covered by topical report ANP10337P-A)
- The docketed analysis of the NuScale fuel assembly design (covered by technical report TR081651127P) 4 Non-Proprietary
Summary of ANP-10337P-A, PWR Fuel Assembly Structural Response to Externally Applied Dynamic Excitations Presents a generic methodology to evaluate PWR assembly structural response to externally applied forces Considers irradiation effects Establishes protocol for benchmark testing Defines acceptance criteria Horizontal and vertical dynamic finite element models Structural analysis of limiting 3D deflection Evaluation of grid impact forces against allowable limits Used for demonstrating compliance with GDC 2 and 10 CFR Part 50 Appendix S Consistent with guidance provided in SRP Section 4.2 Appendix A Contains 9 conditions and limitations 5
Non-Proprietary
NuScale Fuel Design Based on Framatome 17 by 17 HTP design M5 fuel pin cladding Zirc-4 guide tubes HTPTM grids HMPTM bottom grid Differences
~1/2 length Five grids (vs. seven) 6 Non-Proprietary
Modifications to Methodology ANP-10337P-A fuel assembly model has been modified for the NuScale fuel assembly design
- Shorter length
- Fewer grids The staff finds that the dimensional modifications to the model from ANP10337P-A accurately represent the NuScale design and are consistent with the general methodology Axial coolant flow damping is ignored
- ANP-10337 uses fixed generic damping values that credit axial flow damping and require justification on the basis of test data. NuScale modifies the methodology to propose a different set of damping values specific to the NuScale design and are justified with test data.
The staff finds that by providing test results on the NuScale fuel assembly, NuScale is following the methodology from ANP-10337P-A. Additionally, NuScale ignores any potential flow damping which the staff finds conservative and acceptable.
7 Non-Proprietary
Modifications to Methodology Fuel assembly characterized for the first three mode shapes instead of five
- The typical mechanical testing protocols defined in ANP-10337P-A were written for typical full length fuel, which would naturally have more relevant flexural mode shapes than a shorter assembly with fewer grid spacers.
The staff finds that the use of three mode shapes for NuScale to be acceptable based on the comparison of the primary mode shapes versus the fuel assembly motion spectrum.
The staff also notes that while ANP-10337P-A requires the characterization of the first five mode shapes, only the first three are used in the model.
8 Non-Proprietary
Limitations and Conditions 9
Non-Proprietary L&C #
Topic Summary of Disposition 1
Grid Behavior The NuScale grid design is exactly the same grid design used as an example in ANP-10337.
2 Grid Deformation Applicability Limits The NuScale grid design is exactly the same grid design used as an example in ANP-10337.
3 CASAC The NuScale evaluation is performed using a version of CASAC that is consistent with this L&C.
4 Current Fleet The NuScale design is a significant change from the current fleet, but the technical information and analysis documented in reports and RAI responses, as well as PNNL independent confirmatory analysis, addresses all concerns.
5 Damping NuScale proposed and justified specific horizontal damping values that differ from the generic damping values.
Limitations and Conditions 10 Non-Proprietary L&C #
Topic Summary of Disposition 6
Fuel Rod Evaluation NuScale performed fuel rod evaluation that meets this L&C.
7 Control Rod Locations NuScale used the control rod location stress limits to meet this L&C.
8 3D Loads NuScale performed 3D analysis of loads to meet this L&C.
9 Grid Deformation Model Limits The NuScale grid design is exactly the same grid design used as an example in ANP-10337. The grid deformation limit on the impact model is not exceeded.
Staff SER Conclusions The staff concludes that the NuScale fuel assembly meets the conditions and limitations associated with the referenced methodology topical report ANP-10337P-A The staff concludes that the modifications to the approved methodology are appropriate for the NuScale design are acceptable The staff finds that the use of ANP-10337P-A is acceptable for NuScale given the modifications outlined in TR-0716-50351-P.
11 Non-Proprietary
Questions?
12 Non-Proprietary