ML18186A571
| ML18186A571 | |
| Person / Time | |
|---|---|
| Issue date: | 05/15/2018 |
| From: | Zena Abdullahi Advisory Committee on Reactor Safeguards |
| To: | |
| Abdullahi Z | |
| References | |
| NRC-3731 | |
| Download: ML18186A571 (100) | |
Text
Official Transcript of ProceedingsNUCLEAR REGULATORY COMMISSIONTitle:NuScale Subcommittee Open SessionDocket Number:N/ALocation:Rockville, Maryland Date: 05-15-18Work Order No.:NRC-3731 Pages 1-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 COMMISSION'S 7 ADVISORY COMMITTE E 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 t ranscript has not been reviewed, 17 corrected, and edited, and it may contain 18 inaccuracies.
19 20 21 22 23 1 1 UNITED STATES OF AMERICA 2 NUCLEAR REGULATORY COMMISSION 3+ + + + +4 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 5 (ACRS)6+ + + + +7 NUSCALE SUBCOMMITTEE 8+ + + + +9 OPEN SESSION 10+ + + + +11 TUESDAY 12 MAY 15, 2018 13+ + + + +14 ROCKVILLE, MARYLAND 15+ + + + +16 The Subcommittee met at the Nuclear 17 Regulatory Commission, Two White Flint North, Room 18 T2B1, 1 1545 R o c k ville Pike, at 1:00 p.m., Walter L.19 Kirchner, Chairman, presiding.
20 COMMITTEE MEMBERS:
21 WALTER L. KIRCHNER, Chairman 22 RONALD G. BALLINGER, Member 23 MICHAEL L. CORRADINI, Member 24 VESNA B. DIMITRIJEVIC, Member 25 JOSE MARCH-LEUBA, Member NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 2 1 JOY L. REMPE, Member 2 PETER C. RICCARDELLA, Member 3 GORDON R. SKILLMAN, Member 4 5 ACRS CONSULTANT:
6 STEPHEN P. SCHULTZ 7 DESIGNATED FEDERAL OFFICIALS:
8 ZENA ABDULLAHI 9 MIKE SNODDERLY 10 ALSO PRESENT:
11 BRUCE BAVOL, NRO 12 MICHAEL BRADBURY, NuScale 13 ALLYSON CALLAWAY, NuScale 14 TIMOTHY DRZEWIECKI, NRO 15 CHRIS KIRBY, NuScale 16 VICK NAZARETH, NuScale 17 JENNIE WIKE, NuScale 18*Present via telephone 19 20 21 22 23 24 25 NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 3 1 C-O-N-T-E-N-T-S 2 Chairman Opening Remarks
............4 3 Overview...................7 4 Power Nuclear Analysis Codes
..........9 5 Code Description
................13 6 Core and Reflector Description
.........16 7 Code Validation and Benchmarking
........19 8 Nuclear Reliability Factor Generation
......30 9 Code Application
................34 10 Critical Heat Flux Correlation
.........38 11 Introduction and Background
...........40 12 Correlation Development
............46 13 VIPRE-01 Code
.................57 14 15 Overview: Power Nuclear Analysis Codes and Critical Heat Flux Correlation
......59 16 Public Comment
.................72 17 18 19 20 21 22 23 24 25 NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 4 1 P R O C E E D I N G S 2 1 2:59 p.m.3 CHAIRMAN KIRCHNER: The meeting will now 4 come to order. This is a m eeting of the NuScale 5 Subcommittee of the Advisory Committee on Reactor 6 Safeguards.
I am Walt Kirchner , S ubcommittee C hair 7 today for t h e review of t he t wo NuScale topical 8 reports, one TR-0616-48793, N uclear Analysis Codes and 9 Methods Qualification, and two, TR-0116-21012, 10 Revision One, NuScale Power C ritical H eat Flux 11 Correlations.
12 ACRS members in attendance today are Ron 13 Ballinger, G ordon Skillman, Michael Corradini, Pete 14 Riccardella, J ose March-Leuba a nd Joy R empe. W e also 15 have a former member and c onsultant, S tephen Schultz, 16 with us today.
17 Dr. Rempe is conflicted on matters related 18 to Studsvik s c a n ning power that's mainly related to 19 the neutronic methods a nd therefore will recuse 20 herself from review of the neutronic methods topical 21 report and any associated letter writing.
22 Zena Abdullahi and Mike S nodderly are the 23 designated federal officials for this meeting.
24 Today the staff, the NuScale applicant and 25 their consultants will brief us on the c ontent of two NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 5 1 topical reports and their applicability to the NuScale 2 desi g n and o perating conditions.
The staff will 3 establish t h e basis for their findings on these two 4 reports.5 We have one bridge line arranged for 6 interested members of the public to listen in during 7 the open portion of the meeting. In order to minimize 8 noise, this line will kept in mute. At the end of the 9 open portion of the m eeting, we will request if anyone 10 listening would like to make further comments.
11 We have not received written comments or 12 requests for time to make oral s tatements from members 13 of the public regarding today's meeting.
14 A separate closed bridge line i s available 15 for N RC and applicants and t heir c onsultants.
And 16 please place y o ur phones on mute to minimize 17 interference.
Also state your n ame, t he organization 18 you are representing b efore we commence the closed 19 portion of the meeting. That's I think, going to be 20 in reference t o those w ho are coming i n on the bridge 21 line for the contractor and the staff.
22 I request all parties to acknowledge and 23 confirm that the participants in the phone c onference 24 are members of staff a nd/or t he NuScale applicant and 25 their consultants. And that's obviously relevant to NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 6 1 the closed portion of the meeting.
2 As t he meeting is being transcribed, I 3 request that participants use the microphones located 4 throughout this r oom when addressing t he subcommittee.
5 Participants should first identify themselves and 6 speak with sufficient clarity and volume so that they 7 can be readily heard.
8 Let me r emind yo u t o please ensure that 9 all electronic devices have b een placed in silent mode 10 to minimize disturbances during the meeting.
11 We will now proceed with the meeting and 12 I call -- oh, pardon me, Vesna Dimitrijevic has also 13 joined us for the record.
14 MEMBER RICCARDELLA: Walt?
15 CHAIRMAN KIRCHNER: Yes, sir.
16 MEMBER RICCARDELLA:
I am also c onflicted 17 on this topic so I will not participate i n the 18 deliberations.
19 CHAIRMAN KIRCHNER:
On both neutronics and 20 CHF? Both topics?
21 MEMBER RICCARDELLA: I believe so.
22 CHAIRMAN K I R C HNER: Okay. Okay. T hank 23 you. And now we will proceed. Who is going to be up 24 first? A llyson, are you s tarting? Or Jennie? O kay. 25 Please.NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 7 1 MEMBER C ORRADINI:
You n eed the g reen 2 light to shine.
3 CHAIRM A N K IRCHNER: Yes. And pull it 4 closer to you if you can. That will help.
5 MS. WIKE: I apologize for the brief n oise 6 as I'm moving. So my name is Jennie Wike. I am the 7 licensing manager for NuScale's DCA review. So I'll 8 kick off our first presentation.
9 You know, a s Chairman Kirchner m entioned, 10 NuScale i s here today to present on two t opics. W e're 11 going to start out with the topical r eport on nuclear 12 analysis codes and methodology.
13 First, we're going to do some 14 introductions of who's presenting on this topic. So, 15 you know, I already introduced myself.
16 I'm the NuScale licensing manager. My 17 background, I've been with NuScale for r o u g h ly four 18 years. Previous to this, I worked at Xcel Energy at 19 the Monticello and Prairie Island Nuclear Generating 20 Plants. And prior to t hat, I did some R&D work 21 because I graduated from the University of Wisconsin 22 with a materials science degree and d id some R&D work 23 before moving into nuclear power.
24 CHAIRMAN KIRCHNER:
Does that c onflict our 25 chairman?NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 8 1 MEMBER CORRADINI: No.
2 CHAIRMAN K IRCHNER: No. T hank you. I just 3 wanted to understand.
4 MEMBER C ORRADINI:
She's in the w rong 5 department.
6 MEMBER REMPE: You'll hear h i m s ay it's 7 okay since she didn't g o to that department that he's 8 in.9 MS. WIKE: B u t we were right next d oor, 10 connected by the skyway. All right. Allyson.
11 MS. CALLAWAY:
S o my name is Allyson 12 Callaway.
I'm the supervisor of the nuclear analysis 13 group and the interim s u p e rvisor of the core form 14 hydraulics group.
15 I've been with NuScale for eight years. 16 Before that, I came from Oregon State University from 17 their nuclear sharing department. Go ahead.
18 MR. KIRBY: My name is Chris Kirby. I'm 19 a consultant with Structural Integrity Associates.
20 I've been doing work for NuScale for about five y ears 21 in the nuclear analysis and core design group.
22 Before that, my experience i s with San 23 Onofre Generating Station for about six years during 24 core design and nuclear analysis in a nuclear fuel 25 management group. And before that I worked at Bettis NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 9 1 Atomic Power L aboratory for a year working on the core 2 designs.3 And my educational background is a degree 4 in physics a nd a degree in nuclear e n gineering from 5 the University of Michigan.
6 MR. NAZARETH:
And I'm Vick Nazareth.
I'm 7 the director of nuclear fuel at Structural Integrity 8 Associates. My background is I worked at Combustion 9 Engineering for 10 years. And t hen I w orked a t San 10 Onofre for 25 years. I was the last director of 11 nuclear fuel at San O nofre. A nd unfortunately Harold 12 isn't here or he'd remember that.
13 So I've worked i n the industr y f o r 35 14 year s , all i n n uclear fuel, different aspects of 15 nuclear fuel.
16 MS. CALLAWAY: Okay. So with that we'll 17 get s t a rted w ith the open session for the nuclear 18 analysis codes and methods topical report.
19 A quick agenda. This is the a g enda for 20 the open session. Some of these t opics w e'll cover in 21 more detail in the closed session.
22 So we'll g o o v er an overview of the 23 purpose of t he topical r eport a n d t h en a high l evel 24 brief overview of the c ode syste m t hat w e're 25 qualifying.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 10 1 We'll give a r eview of some of t he 2 relevant aspects of the NuScale reactor design. And 3 we'll talk about the overall validation approach and 4 the benchmarking we've d one a s far as the topical 5 report, generation of our n uclear reliability factors 6 and some of the a pplications that NuScale is g oing to 7 use the code for.
8 So this i s just a quick o verview o f what's 9 in the topical r e p o r t. So the topical report is 10 seeking a pproval to u se CMS5 code s uite from Studsvik 11 for physics design and analy s i s f o r the NuScale 12 reactor.13 So within the topical report, w e've 14 benchmarked this code for NuScale applications a nd for 15 the NuScale design. With the b enchmarki n g w e've 16 developed biases and bias u ncertainties and developed 17 nuclear reliability factors out of that whic h will 18 mostly be referred to as NRFs f rom here on out by us, 19 I think.20 And then the culmination of the topical 21 reports is the validation of the c o d e for physics 22 applications for NuScale.
23 MEMBER MARCH-LEUBA:
Let me ask a 24 question, a different question. I'm asking about 10 25 CFR Appendix B, particularly when the t ypical paradigm NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 11 1 is for vendors to have t heir own codes, which t h ey 2 have licensed and approved and t hey m a i n tain. It's 3 not unusual for Studsvik for be part of that.
4 But here, who i s going to be the holder of 5 the l icense? Who's in charge? W ho is responsible to 6 do Appendix B on those codes?
7 MS. WIKE: Sure. S o N uScale has an 8 approved QAPD topical report. A nd so we do have a 9 l i c e nse. T hough I say license, just utilizing your 10 words, w e just have an a p p r oved t opical report to 11 implement Appendix B at NuScale for our applications 12 across --13 MEMBER MARCH-LEUBA: I'm more interested 14 on the codes themse l v e s. W hen you're n ot the f inal 15 repository for the code, like I k now, this student in 16 Nigeria finds a problem with C ASMO5 a nd reports it to 17 Stu d s v i k, h ow does t hat c hange translate into the 18 planned operation?
19 MS. WIKE: Right. S o we would be notified 20 through a P art 21 notification because we would be 21 using that code.
22 MEMBER MARCH-LEUBA:
So you're going to 23 get periodic updates from Studsvik?
You'll always be 24 using the latest version o r the version that you f roze 25 in 2018?NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 12 1 MS. CALLAWAY:
We'll be using the 2 dedicated version, the version that we've qualified.
3 And then we would requalify any n ew version that we'd 4 like to upgrade to.
5 MEMBER MARCH-LEUBA: So once you qualify 6 the code, it becomes your version of t he c ode even 7 though you didn't change any code. And t hat's the one 8 that is approved, right?
9 And then that c ode derived from a 10 repository somewhere in Studsvik, that somebody f ound 11 a mistake on that one. And that needs to eventually 12 migrate into your version.
13 MS. WIKE: Mm-hmm. S o what we're seeking 14 approval o f in our topical report, and let me know if 15 this better answers your question, we're approving the 16 application of the code to the NuScale analysis.
17 MEMBER MARCH-LEUBA: But not the code.
18 MS. WIKE: But not the code itself.
19 MEMBER MARCH-LEUBA:
I'm worried a little 20 bit it's a different problem, but the application of 21 Appendix B to codes that don't belong to me.
22 MS. CALLAWAY:
So in g eneral, if an e rror 23 is identified, we would either reconcile the error or 24 upda t e t o a newer code version where that error has 25 been resolved and then revalidate through our NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 13 1 dedication process.
2 MEMBER MARCH-LEUBA:
I w a nt you to say 3 that you will keep the codes up to date not -- or at 4 least y ou tried to for your mistakes.
You have to 5 evaluate i t if the change is s ignificant.
And if you 6 change it, at which point do you reevaluate?
7 MS. WIKE: Yes. Ou r A p p endix B ravo 8 Program would require us to evaluate any errors. So 9 if Studsvik found a n error in the c ode a nd t hey 10 communicated to that us, usually through a Part 21 11 notification, then we would evaluate it under Appendix 12 Bravo. And at that point we'd have to, as Allyson 13 mentioned, either resolve it because maybe the error 14 doesn't i mpact how we're applying the code. B ut if it 15 does i mpact what we're doing, certainly we would have 16 to address that.
17 MEMBER MARCH-LEUBA: Yes. I have one or 18 two reservations that when there's multiple ownership 19 that those things become difficult.
20 MS. CALLAWAY:
Okay. So we'll cover t hose 21 codes a little bit more in the closed section. This 22 is the initial high level overview o f the codes so 23 starting CASMO5, that's a lattice physics code. It's 24 using ENDF/B-VII.1.
And it's the 2 D transport solver 25 that develops the nuclear data in cross-sections.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 14 1 The CMSLINK compiles all the cross-2 s ections into a library and that library i s t h e 3 p rimary input into SIMULATE5.
SIMULATE5 uses t h e 4 diffusion equation in a 3D model basically built u p of 5 the cross-s e c t i ons from t he library using 3D core 6 simulation.
7 So that's the general code flow. CASMO5 8 and SIMULATE5 are the latest v e rsions of the codes. 9 CASMO4 a nd SIMUL A TE3 are fairly prominent in the 10 industry.
And so these are the latest versions.
11 Studsvik has just also sub m itted a generic topical 12 report for us.
13 MEMBER MARCH-LEUBA:
Are you already 14 making commercial u s e of CASMO5 approved t o d ate in 15 the U.S.?16 MS. CALLAWAY:
Duke uses C ASMO5 c urrently.
17 I believe t hey've licensed that t hemselves.
And I 18 think that D ominion is o r will be going through an 19 8311 with Studsvik's general code.
20 MEMBER MARCH-LEUBA:
T he way I worded the 21 question is CASMO5 on paper is infinitely s uperior to 22 CASMO2 f o r s ure, right? The question i s we've been 23 tweaking those old codes f orever and not i n just 24 special factors here and there to make them work.
25 And now when y ou work, like, on 5 m aybe NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 15 1 those three factors don't a pply. So I'm interested to 2 follow-up o n benchmarking against reoperating 3 conditions in real plants.
4 How do they -- better code follows the old 5 plant. And obvi o u s l y you're not going to have a 6 NuScale core t o do that, b ut y ou should be plugged in 7 on experiences from Duke or whoever h as it or European 8 experience to make sure that you don't make the same 9 mistakes.10 DR. DRZEWIECKI: I'm sorry. This is Tim 11 Drzewiecki.
I mean, t hat's something t hat will be 12 covered in our presentation. There is a generic CMS 13 fact topical r eport. And t here is plenty of operating 14 plant benchmarking that's reflected in that topical 15 report, over 63 plant cycles, I believe.
16 MEMBER MARCH-LEUBA:
Mostly foreign 17 plants?18 DR. DRZEWIECKI: No. It's U.S. plants.
19 MEMBER MARCH-LEUBA:
A U.S. plant, yes. 20 Thanks.21 MEMBER SKILLMAN: Does Studsvik maintain 22 a user's group for their c odes? And I presume if they 23 do, NuScale is a member?
24 MS. CALLAWAY: Yes.
25 MEMBER SKILLMAN: For both.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 16 1 MS. CALLAWAY: Yes to both.
2 MEMBER SKILLMAN:
Both of their codes. 3 Thank you.
4 M S. CALLAWAY:
Okay. W ith that, I will 5 turn it over t o Chris, and h e's going t o cover some of 6 the more relevant aspects of the NuScale design.
7 MR. KIRBY: So this sl i d e j ust presents 8 some general parameters of the NuScale core and fuel 9 design. And as it relates to the codes, modeling of 10 the NuScale core is not much different than modeling 11 typical PWR except for the size and the power level.
12 As you can see, the core is composed o f 37 13 assemblies with 16 CRA s. The fuel assemblies are 14 standar d 17 x 17 design, 24 guide tubes and one 15 instrument tube.
16 The fuel has a maximum UO2 enrichment of 17 95 p ercent, UO2 and its encapsulated M5 cladding.
An 18 active fuel length is two meters.
19 The control routes have a s plit 20 composition of 37 centimeters of silver indium cadmium 21 at the bottom and that's followed by B4C at the top 22 for the remainder of the rod. And then gadolinia is 23 used as a printable absorber, which is c o m b ined 24 homogeneously with the UO2 and fuel pellet.
25 And one of the features of the NuScale NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 17 1 design, as it relates to safety, is its resiliency to, 2 or stability with respect to xenon oscillations.
3 So analysis that we've done with SIMULATE 4 has shown when we perturb the core to c ause a x enon 5 transient t hat the xenon o scillations are quickly 6 damped out and t h e c o re returns t o equilibrium, 7 usually within one oscillato r y cycle. So it's 8 different than a big PWR. It's very stable.
9 MS. CALLAWAY:
I f I could interrupt 10 quickly, I think you said it was 95 p ercent max 11 enrichment. You meant --
12 MR. KIRBY: 4.95 percent, y es. Thank you 13 for that.14 MEMBER R E MPE: If I could interrupt for a 15 second, j ust for clarification.
When I was l ooking at 16 this report versus the CHF report, which c learly said 17 a particular fuel type, I didn't see a specific fuel 18 type identified. And somewhere I thought in some of 19 the material we were given there was a time w here 20 NuScale didn't have a fuel or they switched from one 21 fuel to another.
22 And I w a s j u s t curious, is this topical 23 for the particular fuel type t h a t y o u a re now g oing 24 with? Or what's the story o n t h e f u el? I s this 25 topical for it?
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 18 1 MS. CALLAWAY: So the generic parameters 2 of the fuel type that apply, whether we are using a 3 prior fuel design or this fuel design, is the general 4 applicability of this topical report. So the 17 x 17.5 MEMBER REMPE: So when we write, or when 6 the Committee writes a letter o n this, they s hould not 7 reference the s pecific fuel type on this topical 8 report. You want i t to be more general for more than 9 the AREVA fuel type t hat you're currently g oing w ith. 10 Correct?11 MS. CALLAWAY: Yes.
12 MEMBER REMPE: Okay.
13 DR. DRZEWIECKI:
This is T im again. This 14 is s omething w hich is addressed in the staff's safety 15 evaluation that t here i s s ome flexibility in terms of 16 your fuel type, but there's also a l imitation provided 17 in the SE in terms of there's only certain materials 18 that are inside of the CMS5 code suite. And so they 19 are limited, obviously, to those.
20 MEMBER REMPE: Thank you.
21 MR. KIRBY: So as you can s ee in this 22 slide, it's a depiction of the heavy reflector around 23 the core. That reflector contains cooling channels to 24 remove the heat generated by the gamma radiation.
And 25 the heavy r eflector for N u S c a le was designed to NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 19 1 control leakage, improve fuel utilization and evenly 2 distribute power throughout the core.
3 As can be seen in the figure, the 4 reflector thickness varies around the core a nd ranges 5 from about 10 centimeters to about 30 centimeter.
6 Standard reflector modeling in CASMO5 and 7 SIMULATE5 is used t o model t h e reflector, but the 8 number of r eflector sections m o d el d epending on the 9 reflector geometry.
10 Modeling m u l t i p l e r e f l e c t o r s e g m e n t s b ased 11 upon position around the c ore and material composition 12 of the v arious segments was done to m aintain the 13 fidelity of the model, k eeping the distinct regions of 14 the reflector separate.
15 The ability of SIMUALTE5 to accurate m odel 16 the S IMULATE ref l e c tor h as been demonstrated by our 17 core benchmarking, which w e'll go into a l i ttle bit 18 later and specifically comparisons to MCNP.
19 And now we'll go back to talk a little 20 about the validation of the code with Allyson.
21 MS. CALLAWAY:
So w e used three d ifferent, 22 I guess, primary categories for be nchmarking.
The 23 first one was code-to-code benchmarking with M CNP, 24 empirical benchmarks of critical c onfigurations and 25 experimental reactors and commercial reactor benchmark NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 20 1 to TMI1.2 MEMBER MARCH-LEUBA:
So you say you're 3 doing a full core MCNP?
4 MS. CALLAWAY: Yes.
5 MEMBER MARCH-LEUBA: Full three?
6 MS. CALLAWAY: Mm-hmm.
7 MEMBER MARCH-LEUBA:
You have p lenty of 8 servers to run it on?
9 MS. CALLAWAY: It takes awhile to run.
10 MEMBER MARCH-LEUBA:
It t akes awhile, 11 right?12 MS. CALLAWAY:
Mm-hmm. So t hose 13 benchmarks comprise ou r c o de v alidation.
And the 14 results of the code validation are used to develop 15 biases and bias uncertainties.
16 MEMBER MARCH-LEUBA:
J ust curious, o n MCNP 17 model, to what level do you homogenize?
You d on't 18 model every pin do you?
19 MS. CALLAWAY: Yes, we do.
20 MEMBER MARCH-LEUBA: You model every pin 21 on every fuel assembly?
22 MS. CALLAWAY: Yes.
23 MEMBER MARCH-LEUBA:
I'd love t o see that 24 model.25 MR. KIRBY: R emember, it's only 37 NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 21 1 assemblies.
2 MEMBER MARCH-L E U BA: Y es. But t here is 3 the 17 x 1 7 pins. I k now MCNP allows you to repeat 4 the limits, b ut, geez, you're talking d issertation for 5 if you b r i n g it out, you get your Ph.D. just out of 6 it.7 MS. CALLAWAY:
Okay. S o the results of 8 the benchmarking we u sed to d e v elop b iases and bias 9 uncertainties are tolerance limits as its given h ere. 10 And those values w e develop nuclear reliability 11 factors to encompass them and the nuclear reliability 12 factors a nd the validate d c o de are ready for 13 downstream application.
14 So that's the general process t hat we 15 followed for v alidation and the basic flow of the top 16 core part that we're talking about.
17 Okay. So a little bit m o r e on code to 18 code --19 MEMBER REMPE: I have another question on 20 that slide, too. And this is more because, again, of 21 the interface with the t hermal hydraulics.
NuScale is 22 going to operate at lower pressures and lower flow 23 conditions.
24 And, again, I'm not an e xpert what all 25 Studsvik did to validate the i r c o des, but in a ll of NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 22 1 these benchmarks, did t hey consider a case that w ould 2 give you appropriate benchmarks that w ould consider 3 void coefficients and moderate greater coefficients 4 because of the different conditions that you're 5 operating at?
6 I m e a n , I know the benchmark of BWR 7 conditions as w e ll as PWR conditions.
But did you 8 look and say, oh, yes, this one really will give us 9 the right v oid coefficient and moderator coefficient?
10 MS. CALLAWAY:
So the closest benchmark 11 that we have for that is the commercial benchmark.
12 MEMBER REMPE: PMI1?
13 MS. CALLAWAY:
A nd it's 400 psi, I think, 14 lower pressure, but generally, f airly similar 15 operating conditions.
Also, w ith the code-to-code 16 benchmark with MCNP, you know, pressure doesn't 17 necessarily draft input. But we looked at a number of 18 different densities of the coolant as p art of that 19 benchmark.
So we get those implicitly in a couple of 20 different ways.
21 MEMBER REMPE: Because a gain, when I t hink 22 about things we've heard so far, A TWS concerns and 23 things like that are more impor t a n t. A nd so that's 24 why I'm real curious on that.
25 MS. CALLAWAY:
And so moderator NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 23 1 coefficients would be s imilar with the benchmarking we 2 looked at.
3 MR. NAZARETH:
And so let me add a little 4 bit more to that. Typically when you do a code like 5 this, am I on or off? Sorry.
6 Typically when you do a code l i k e t his, 7 you benchmark to operating data. T hat's t he key 8 aspect of what it is, but NuScale h as no o p e rating 9 data. So the benchmarking d one here t hat's described 10 over here is very extensive t o make up for whatever it 11 is you're going to have.
12 So the MCNP, you have t o g o into that 13 level of detail because you h ave t o have t wo c odes 14 that match up perfectly to say that the benchmarking 15 was okay. Okay?
16 And then same t hing with the empirical 17 benchmarks with the criticality and so o n. N o w TMI 18 data is t he closest data w e could find that will give 19 us the k inds of things we w anted to do for w hich 20 you're talking about. And so we used that.
21 And then ultimately we s et up, we compared 22 against t he industry standards j ust to s ee that w e're 23 not off, t hat we're c onsistent with what the industry 24 standard was for those kinds of item.
25 And so, these in the end, we a dded NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 24 1 conservatisms t o account for things we didn't k now. 2 Okay? We expect to verify that during startup testing 3 in this middle half of this table over here.
4 When it says update methods, we actually 5 put t he methods in a n d how w e validate it a fter we get 6 actual startup data a n d make sure it's s till 7 conservative.
Okay? But we had to do much more 8 extensive benchmarking becau s e of the fact t hat the 9 NuScale conditions are unique.
10 MEMBER REMPE: Thank you.
11 MEMBER SKILLMAN:
Let me expand on Dr.12 Rempe's question, please, Vick.
13 MR. NAZARETH: Sure.
14 MEMBER SKILLMAN:
T he first couple cycles 15 of TMI1 were at 2413, not 2 568, four pumps r u n n i ng. 16 Very high Reynolds numbers.
17 MR. NAZARETH: Yes.
18 MEMBER SKILLMAN:
And an e nrichment that's 19 very different than yours.
20 MR. NAZARETH: That's correct.
21 MEMBER SKILLMAN:
And e arly, early TMI 22 enrichments were 3.5, 4.1 max. And you're 4.95 with 23 a 24 month fuel cycle. Why is the TMI data 24 applicable?
25 MR. NAZARETH:
So the TMI -- okay. So the NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 25 1 TMI data is applicable to t he p o i nt o f s imulating 2 actual operating data. O k ay? It could have t aken 3 many d ifferent things l ike that. T he specific things 4 with enrichment and all of that, we did the code-to-5 code benchmarking to m atch t hat up really well. O kay?6 And the TMI data is like t he last step to 7 close the ranks to make sure we're actually using an 8 operating data from a plant to match up as well as we 9 can. And then we added s ome more conservatism to the 10 top of that. Okay?
11 S o w e b r ought i n -- there is m any -- i n 12 the Studsvik generic topical report, they brought up 13 data from many different plants, most of them Dominion 14 plants here t oday. O kay. So they had a broader b ased 15 look at all the plants. Okay?
16 So w h a t w e did in the end i s we came 17 together w ith that and said, well, for w hatever we 18 don't have -- b e c a use you c an run infinity with the 19 amount of data that you wanted to. Whatever data we 20 don't h ave, we'll m ake certain conservative 21 adjustments to make sure w e're not -- we're w ithin the 22 realm of what we expect to be for this particular run. 23 So it's the best we got, really, to match up with as 24 many things as we could.
25 MEMBER SKILLMAN: Thank you.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 26 1 MR. KIRBY: Can I clarify something?
The 2 two year cycl e l ength doesn't have a blanket 4.95 3 percent enrichment.
That's just the maximum 4 enrichment from the scale. For th e t w o y ear cycle, 5 the average enrichment is 3-1/2, 4 percent, something 6 right around t hose numbers. I just wanted to clarify 7 that.8 MEMBER MARCH-LEUBA:
But do you have 9 gadolinia?
10 MR. NAZARETH: Yes.
11 MEMBER MARCH-LEUBA:
That's s omething that 12 broadly the very early TMI code didn't have.
13 MR. NAZARETH: That's correct.
14 MEMBER MARCH-LEUBA:
That would be the 15 biggest difference.
16 MR. NAZARETH:
And t his is why did the 17 code to k ill kind of thing, right? Because we needed 18 to be able to d uplicate that we could model t hose 19 kinds of things. This is why we also compared it to 20 the industry d ata to make sure t hey were n ot stepping 21 out of things that are different.
B u t gadolinia is 22 fairly well known now. Framatome uses it all the time 23 so it's not that unusual.
24 MEMBER M ARCH-LEUBA:
G oing back to my 25 original comment which y ou probably f orgot a lready is NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 27 1 this are you relying on the Studsvik valuation also?
2 M R. NAZARETH:
Okay. So l et me ad d 3 something m ore to that. Okay? S o Studsvik is an 4 independent resupplier.
S o if there are errors in 5 their code, they're required to t ell NuScale a bout the 6 errors. And t hen NuScale evaluates that to make sure 7 it complies with NuScale's Appendix B program. O kay?8 So for things th a t are nice to h ave, 9 NuScale doesn't have t o take them in o r n ot. With 10 error reporting, it has t o be done and c orrectly.
11 That is a requirement for an Appendix B s upplier. And 12 there is what's called a NUPIC audit that goes back to 13 suppliers of codes and validates them.
14 MEMBER MARCH-LEUBA:
I'm not picking on 15 you.16 MR. NAZARETH: No, no, no.
17 MEMBER MARCH-LEUBA:
I'm trying to 18 understand --
19 MR. NAZARETH:
I'm just explaining the 20 system of our -- because many utilities now are d oing 21 independent analyses, r ight? APS i s doing their. 22 Duke is doing it. Dominion is doing it. We did it.
23 It's ours.
24 So the same kind of thing. We take over 25 whatever t he v endor codes are. It doesn't have to be NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 28 1 a field vendor anymore. Take over the vendor codes.
2 An Appendix B supplier, they're requi r e d to provide 3 you with error reporting.
4 MEMBER M ARCH-LEUBA:
A nd then a re you 5 required to validate your code independently from the 6 vendor?7 MR. N AZARETH: You assess it and you 8 evaluate it independently, c o r rect. You are the 9 licensee.
So this gives t he responsibility to 10 validate.11 MEMBER MARCH-LEUBA:
You cannot rely on 12 the validation that the v endor, Studsvik, probably 13 knows more about this than you do.
14 MR. NAZARETH:
No. You do rely on it 15 because they give you all the information r elative to 16 that. R ight? T h e i mpacts and all o f that, they do 17 the impact assessment and all of that. Okay?
18 So you apply i t t o y ourself what i s t he 19 homogeneric application?
20 MEMBER MARCH-LEUBA: Well, what gives me 21 a very nice warm feeling is well, we just held there 22 are 65 cores t hat we have validated, that's validated 23 on their own. You've done one.
24 MR. NAZARETH: Yes.
25 MEMBER MARCH-LEUBA: So I don't have 65.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 29 1 I have one. Let's degrade for it.
2 MR. NAZARETH:
That's why w e got all this 3 be n c h marking, right? Tons of i t because we try to 4 fill in as many gaps as we can.
5 CHAIRMAN KIRCHNER:
Just out of c uriosity, 6 has Studsvik used this code suite on boilers, on B WRs?7 MR. NAZARETH: They have. The answer to 8 that is yes.
9 CHAIRMAN KIRCHNER: Okay.
10 MR. NAZARETH: Which ones, I'm not quite 11 sure. But the answer to that i s yes. It's 12 generically --
13 CHAIRMAN KIRCHNER:
So that I w ould g uess 14 they w o u l d have benchmarked.
And t herefore, they 15 would h ave data at 1 000 psi and different flow 16 conditions than typical o f the PWR. So i t may provide 17 some confidence that t he code scale through a range of 18 pressures and flows and associated neutronic 19 parameters that are typical.
20 It's almost as if, without making any 21 judgment, it's like the NuScale de s i g n is somewhere 22 between a BWR and a PWR with y our natural circulation 23 and y our lower pressure.
And I g uess we'll hear more 24 about that when we get to critical heat flux.
25 But if Studsvik has benchmarked against NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 30 1 boilers, that's enhanced competence that the code 2 scales through substantially different thermodynamic 3 and neutronic conditions.
4 MR. NAZARETH: Yes. That's interesting.
5 CHAIRMAN KIRCHNER: Okay.
6 MS. CALLAWAY: Okay. So just a bit more 7 detail on the code-to-code benchmarking to start. As 8 we have said, the code-to-co d e benchmarking is CMS5 9 compared to MCNP6. And the benefit here is that w e're 10 comparing two different methods of deterministic 11 versus a s t ochastic method of very detailed M CNP6 12 model.13 Because it's a code-to-code b enchmark, 14 we're not relying o n a f ixed number of data points. 15 We h ave f lexibility i n the number of data points that 16 are availabl e to us. So m ost of t he physics 17 parameters that are important to us f or t he v alidation 18 we h ave t he ability to b enchmark through t his method.19 We can move on to the next s l i d e unless 20 anybody has any questions on that one. S o the 21 empirical benchmarking, the commercial reactor is 22 included in t his but we did do a large amount of 23 critical experiments a nd experimental reactor 24 benchmarking as p art of our empirical benchmarking as 25 well.NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 31 1 And the empirical benchmarking and the 2 commercial reactor benchmarking gives us real data to 3 compare ag a i n st a limited n umber of d ata points and 4 still a substantial amount, we hav e a ctual measured 5 data that we start to get to compare to.
6 MEMBER MARCH-LEUBA: What I don't see on 7 that slide is core depletion. I mean, it feels like 8 yo u c onsider it more to a particular space, the 9 operating condition, and calculated it to p ower 10 distribution.
Did you do the core depletion to m atch 11 the K effect as a function of time?
12 MS. CALLAWAY:
Yes, y es. We get t hat out 13 of the TMI benchmark.
14 MEMBER MARCH-LEUBA: That's the TMI?
15 MS. CALLAWAY: Mm-hmm. Yes. So there's 16 two cycles of core deletion.
17 MEMBER MARCH-LEUBA:
T hat's much harder to 18 do than a single point.
19 MS. CALLAWAY:
Y es. And so c ommercial 20 d a t a b enchmarking, we've covered this quite a bit 21 already. So TMI, you know, on cy c l e s 1 and 2 are 22 modeled. We get all of our key ph y s i cs p arameters 23 benchmarked through t his commercial reactor 24 comparison.
25 So the commercial benchmarking, the o ther NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 32 1 empirical benchmarking
, t h e c o d e-t o-c o d e b e n c h m a rking, 2 as a recap, w e use the results of those in combination 3 with developed biases and bias uncertainties and use 4 those to develop NRFs for NuScale's a pplication of the 5 code.6 And then the final recap of the process.
7 I guess, I mostly just said all of this. So o nce the 8 NRFs a re developed, we use t hose for the initial 9 NuScale design. And as soon a s w e're starting up, we 10 have the ability to validate those NRFs and t hen s tart 11 collecting additional data to e ither confirm or update 12 the NRFs once we have N uScale's specific data 13 available to us.
14 MEMBER MARCH-LEUBA:
A nd these are 15 penalties when they a re effective?
Give me, l ike, an 16 example of an NRF.
17 MR. NAZARETH:
Can we talk about t hat more 18 in the c losed session? Because w e're actually 19 presenting some of those things there.
20 MS. CALLAWAY: I can give you an example 21 for now would be a penalty to use your words on 22 control out growth.
23 CHAIRMAN KIRCHNER:
And so since we're in 24 open session, I think it's useful for the record and 25 the p ublic to j u st compare your NRFs that you NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 33 1 generated with utility. C ould you highlight t hat? 2 Are they bounded by typical v alues used by u tilities?
3 You have a table on Page 78 of your report, industry 4 standard values.
5 MS. CALLAWAY: Yes. So that's --
6 MR. NAZARETH: Yes, so.
7 CHAIRMAN KIRCHNER:
That's public 8 information.
Can you just go qualitatively, just say 9 how your NRFs compare with i ndustry bench m a r k s or 10 standards?
11 M R. NAZARETH:
O kay. Our NRFs are mo r e 12 conservative than the industry benchmarks then. O kay? 13 So the specific details we will provide in the closed 14 session.15 CHAIRMAN KIRCHNER: Sure.
16 MR. NAZARETH:
But in general, that middle 17 bullet that says a s conservative factors, t hey're set 18 up to b e conservative r e lative to a ll the types of 19 benchmarking that we did, okay, a t a 95/95 probability 20 confidence level.
21 And we'll talk a b o u t -- we have s ome of 22 the statistics in the topical report for anything else 23 you w ant to see. But they a re more conservative than 24 in the industry.
25 CHAIRMAN KIRCHNER:
And so going into NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 34 1 startup testing, you're u sing more conservative 2 nuclear reliability factors t han are t y p i cal in the 3 industry?4 MR. NAZARETH: Yes.
5 CHAIRMAN KIRCHNER: That's what I wanted 6 you to say.
7 MR. NAZARETH:
Yes. There is one 8 parameter that is more conservative, and I'll h ave to 9 explain it.
10 CHAIRMAN KIRCHNER: Okay.
11 MR. NAZARETH:
In t he closed session. 12 Okay?13 CHAIRMAN KIRCHNER:
A ll right. Thank you.14 MS. CALLAWAY:
Okay. I'll l et Chris take 15 over the last couple of slides for this s ession on the 16 code application.
17 MR. KIRBY: O kay. So NuScale was planning 18 to u se the CMS5 to perform core designs a nd to provide 19 input to safety analysis. And in doing so when they 20 performed these calculations, they will be applying 21 N R F s t o the CMS5 results in order to e nsure a 22 conservative result on the analysis.
23 They also w ould like to u se C M S 5 to 24 perform startup physics test i n g and a lso do core 25 follow-up predictions.
And in using the code i n this NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 35 1 manner, that w ould also help to validate the NRFs that 2 have already b e e n established and provide data to 3 update their NRFs when an enough data h as been 4 presented.
5 So in summary, NuScale has performed 6 extensive benchmarking into t he CMS5's code suite for 7 application to the NuScale design. The benchmarking 8 process has r esulted in the development of nuclear 9 reliability factors for use in the application o f the 10 code system to perform n u c l e ar analysis.
And t hese 11 NRFs will be validated a nd u pdated when o perating data 12 from NuScale modules becomes available.
13 MS. CALLAWAY:
That is the end of our open 14 session of material f o r nuclear analysis, codes and 15 methods topical report.
16 CONSULTANT SCHULTZ: Allyson, I have a 17 general question. A n d it has to d o with NuScale 18 support of the overall application and basically who 19 did what?20 MEMBER MARCH-LEUBA:
Steve, can you put 21 the green light? Oh, you have? Sorry.
22 CONSULTANT SCHULTZ: Oh, it's o n. And the 23 question is, have you some consultants in your -- as 24 I understand it in your application, you relied upon 25 Studsvik methodology.
I d on't know how much Studsvik NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 36 1 participated in this particular application.
What I'm 2 most interested in is going forward.
3 NuScale i s going to have a staff that's 4 going to move this in to the next p hase of the 5 licensing process. And I wanted to get an 6 appreciation for what NuScale i s d o ing to make sure 7 that the staffing that they have is well-experienced 8 in doing that application.
9 It has certainly benefitted from 10 consultants in developing the licensing application.
11 But going forward, you might leave those consultants 12 behind and have a group that's going to make this 13 satisfactorily move forward. And where are yo u n ow 14 and where are you going?
15 MS. CALLAWAY: Okay. So Studsvik didn't 16 participate at all in the development o f this work 17 short o f obviously supplying the softwar e. B ut the 18 rest of the v a l i d a tion work and the contents o f the 19 topical report and the rest of t he work that supports 20 what's in the topical report.
21 CONSULTANT SCHULTZ: But you must have 22 consulted with t h e m to at least develop an 23 understanding that what y ou w ere doing was an 24 appropriate application of the code?
25 MS. CALLAWAY:
Yes, yes. So t hey do NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 37 1 provide training on the code, yes.
2 CONSULTANT SCHULTZ: Good.
3 MS. CALLAWAY: But otherwise the use and 4 application of it is t hen independently owned as a 5 function by N u Scale. Does that f ully answer your 6 question?7 CONSULTANT SCHULTZ: A nd that i ncluded the 8 development and submittal of the application and the 9 RAI responses and so forth?
10 MS. CALLAWAY: Yes.
11 CONSULTANT SCHULTZ: Okay.
12 MS. CALLAWAY:
Yes. So it will be 13 NuScale's staff or augmented staff. But the work and 14 the process and the t e chnology and ownership of the 15 actual property is also --
16 CONSULTANT SCHULTZ: Augmented staff, and 17 is t hat augmentation g oing to con t i n ue or is it 18 envisioned to be more of an in-house activity?
19 MS. CALLAWAY:
The s cope of t h e topical 20 report was for approval for NuScale Power to a pply 21 these m ethods. And certainly we do intend to be a 22 design center for our future plants. And dependent on 23 how many plants we have --
24 CONSULTANT SCHULTZ: Understood.
25 MS. CALLAWAY:
-- that will determine our NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 38 1 staffing.
But certainly we would hope to have 2 hundreds. If there's any potential customers --
3 CONSULTANT SCHULTZ: T hank you. That 4 clarifies my concern and your cons i d e ration. T hank 5 you.6 CHAIRMAN K IRCHNER: Okay. W h y d on't we 7 continue with the CHF correlation presentation.
8 MS. WIKE: All right. So we're moving on 9 to the next NuScale o pen presentation on the critical 10 heat flux correlation topical report. So we do have 11 a new presenter joining us at the table. So I'll have 12 Mike introduce himself, give a little bit of a short 13 bio before we r o l l straight i nto the P owerPoint 14 slides.15 MR. BRADBURY:
O kay. Good a fternoon.
My 16 name is M ike Bradbury.
I'm staff aug to NuScale from 17 ISL. And I was the lead of t he CHF correlation 18 development.
19 With some of my prior experience, I worked 20 on mPower mostly thermal hydraulics stuff. I worked 21 at AREVA for six or seven years w ith PPR and such 22 things. And then --
23 CHAIRMAN KIRCHNER:
M ichael? Can I 24 interrupt and ask y ou j ust pull y o ur microphone a 25 little closer and speak out a little more?
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 39 1 MR. BRADBURY: Okay.
2 CHAIRMAN KIRCHNER: Please.
3 MR. BRADBURY:
A nd then prior to AREVA, I 4 worked at Cappell for six or seven years as well. So 5 I think that's me.
6 All right. So for the agenda, I'll just 7 do a quick overview of what the CHF topical is, some 8 introduction background information, the overview of 9 the development o f the NSP1, 2 and 4 correlations and 10 then a little bit of a discussion about VIPRE and our 11 use of it.
12 Okay. So the overview, essentially 13 NuScale was s eeking NRC approval to use both, or 14 either, the NSP2 or N S P4 CHF correlations in safety 15 analysis.
The CHF testing that w e have w as performed 16-- we had actually two kind of rounds of testing.
17 The first was done at Stern Labs and then 18 we have additional from the F ramatome's KATHY facility 19 i n Germany. And VIPRE was used in t he correlation 20 development and i s also used as the analysis tool for 21 safety analysis.
22 So this s lide, we'll j ust kind of get into 23 a little bit what m akes, you kn o w , NuScale special. 24 The NuScale S MR o perated under some unique conditions, 25 most notably the l ow f low from natural circulation NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 40 1 since we don't have forced flow pumps.
2 MEMBER CORRADINI:
So ma y be this is in 3 closed session. So you tell me to stop. W here do you 4 measure the flow in the design? We can wait.
5 MR. BRADBURY: In the design --
6 MEMBER CORRADINI:
In other words in 7 actual operation.
8 MR. BRADBURY:
In a ctual o peration, I 9 would have to get back to you. I'm not s ure exactly.10 MS. WIKE: Yes. Let us get back to you in 11 the closed session.
12 MR. BRADBURY: So, you know, we needed a 13 NuScale specific CHF correlation basically because our 14 flow rates are very l ow. Y ou know, the PWR, the 15 t y pical test in flow r ates go down to about 1/2 16 million pounds p e r hour foot squared. And we need 17 data below that.
18 So that's, you know, we went off and 19 test e d our -- at those conditions, which i sn't 20 necessarily easy. C HF t esti n g at l ow flows can be 21 kind of tricky.
22 We also have a shorter heated length, 23 which does play a little i nto the testing. You k now, 24 ours is a bout a 6-1/2 feet length bundle versus 12 or 25 14 for conventional PWR.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 41 1 So, like I said, we r an two dif f e r e nt 2 campaigns. The first was at Stern and that was back 3 in 2 012, 2013. And then w e d id a prototypical NuFuel-4 HTP2 bundled design test at KATHY in 2016.
5 MEMBER REMPE: S o, I know Stern and K ATHY 6 have no w b e en used quite a bit in various 7 appl i c a t i ons. But I still am interested in how you 8 have confidence in the calibration of the sensors. 9 And I know the report said you had diverse means.
10 And I guess I'm curious i f you know of any 11 cases where they found that a s ensor went bad and they 12 replaced it. Because, you k n o w , if you have two 13 sensors and one is reading different from the other, 14 you d on't know which one i s right. And so I'm curious 15 about that.
16 Is there a potential that they b oth c ould 17 have drifted? And I know there's s omething i n the 18 report that even said, well, all we care about is the 19 difference in temperature.
And, again, if things are 20 drifting, I don't have a lot of confidence in the 21 difference in temperature or flow o r whatever the 22 parameters you're measuring.
23 And so can you give u s a ny of your 24 insights about why you are comfortable and confident 25 of the calibration of the sensors?
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 42 1 MR. BRADBURY:
I'm not aware th a t a ny 2 sensors failed during our test campaign. I don't --
3 MEMBER REMPE: In the past, w hen you 4 talked to them, before you gave them money to do the 5 test, did you ask them about those kind of q uestions?6 MR. BRADBURY:
I believe, yes. A nd we 7 came away with confidence that they would be able to 8 adequately test. I can't speak too much to the S tern 9 data in that regard because that was before my time.
10 But a t l east w i t h K ATHY t esting we, you k now, 11 discussed those things and --
12 MEMBER R EMPE: And what gave you 13 confidence that they were taking care of it?
14 MS. WIKE: Do you mind if I jump in?
15 MR. BRADBURY: Oh, absolutely.
16 MS. WIKE: So we do have, like I 17 mentioned, an approved Appendix B Program. And we did 18 do a QA audit of the testing facilities t o ensure that 19 their controls and how they were run n i n g the 20 facilities met our A ppendix B expectations for 21 quality.22 MEMBER REM P E: But I just am curious in 23 just knowledge of what t hey did -- and I don't know 24 what A p p e ndix B folks who w ere auditing would do to 25 give them that con f i d e n c e. But what do you do? I NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 43 1 mean, I ran tests at a l aboratory.
And I k now some of 2 the things we did and I just am curious in what they 3 did and why you felt comfortable.
4 MR. BRADBURY:
Yes. I'm not sure that I'm 5 the right person to answer that.
6 MEMBER REMPE: I f y ou ha ve time, m aybe 7 there's time to get back to us. I'm just curious if 8 you could write a couple paragraphs and let us know.
9 MR. BRADBURY: Absolutely.
10 MEMBER REMPE: Thank you.
11 MS. WIKE: Okay. Next slide.
12 MR. BRADBURY:
Sure. Al l right. So a 13 little b ackground on the NuFuel-HTP2 d esign itself. 14 We covered this a little bit in the nuclear analysis 15 code of methods. You know, it's a conventional 17 x 16 17 arrayed f uel b u ndle. L ike I said earlier, it's 17 shorter than normal for typical PWRs.
18 We are u sing F ramatome's HTP and HMP 19 spacer grids. And those have been us e d extensively 20 throughout the industry, both in B&W-type plants and 21 Westinghouse type plants. So there's quite a history 22 with those.
23 MEMBER S KILLMAN: Could you please go 24 back? Were the tests that were conducted tests that 25 were conducted at the S tern and KATHY tests that used NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 44 1 an assembly that looked like this?
2 MR. BRADBURY: The one at Stern --
3 MEMBER SKILLMAN:
Let m e say it d ifferent.4 MR. BRADBURY: Sure.
5 MEMBER SKILLMAN:
An assembly that was 6 assembled like this.
7 MR. BRADBURY:
The one a t Stern w as not 8 because that was prior t o us having Framat o m e as a 9 fuel vendor. So the one at Stern, you know, while the 10 lattice was the same, you know, the pitch and the 11 diameters and broads and stuff that a re the same, the 12 grids were just simple non-mixing space requirements.
13 So they would not represent this product.
14 Now what was tested at the KATHY facility 15 was this actual product with the correct sp a n s and, 16 you know, like, f o r instance, the bottom, you k now, 17 gri d b e fore e ven the heated length, HNP, a nd then 18 there's HTPs and there's an HMP at the top. I mean, 19 down to the that, you know, they put all the r ight 20 spacer grids in all the righ t places for t he K ATHY 21 test.22 MEMBER SKI L L M AN: So I hear you s ay for 23 the KATHY test it is virtually an identical --
24 MR. BRADBURY: Yes.
25 MEMBER SKILLMAN: -- device?
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 45 1 MR. BRADBURY: Yes.
2 MEMBER SKILLMAN: Thank you.
3 MR. BRADBURY: Okay.
4 CHAIRMAN KIRCHNER: I think we're -- I'm 5 just s canning your slides, I don't think y ou are 6 showing u s in your slide deck t hat's for the open part 7 the actual test array. It that 5 x 5 or?
8 MR. BRADBURY: Yes. It is a 5 x 5.
9 CHAIRMAN KIRCHNER: All right.
10 MR. BRADBURY:
Which is pretty standard 11 for --12 CHAIRMAN KIRCHNER: Okay.
13 MR. BRADBURY:
All r ight. So a little 14 back g round on the operating conditions.
When we 15 compared it to traditional PWRs, NuScale relies on a 16 much lower f low, o bviously due to t he lack of poor 17 circulation.
And commensurate with that we also have 18 a much lower p ower density for linear heat g eneration 19 rate, whichever way you'd like to look at that.
20 So, you know, i n this plot you can sort of 21 see NuScale as an outlier away from the other PWR 22 plants.23 Now one of the t hings we look at i s Power-24 to-Flow just to see, you k now, it kind of gives you an 25 indicator on how aggressively you're going to be NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 46 1 pushing the thermo-hydraulics.
2 And NuScale's is a little h igher than, you 3 know, othe r d e s igns like EPR, AP1000. But when you 4 compare it to the typical Westinghouse Plant for the 5 AP1000, i t's not drastically higher. So, you k now, 6 that gives us confidence that we're not pushing it so 7 hard that we're going to, yo u k n o w , be pushing 8 ourselves into a constant CHF problem.
9 CHAIRMAN KIRCHNER:
In addition to linear 10 heat rate, what about typical heat fluxes?
11 MR. BRADBURY:
The average heat flux is --12 I want to say it's v ery low. I'm not sure o f an e xact 13 number.14 MEMBER CORRADINI:
W e can get to i t in the 15 closed session.
16 MR. BRADBURY:
Yes, that's fine. I m ean, 17 we can talk about it there.
18 MS. WIKE: Okay.
19 MR. BRADBURY:
Sure. All ri g h t. O kay. 20 So it's a little convoluted h ow w e got to our CHF 21 correlations due to what we were talking about earlier 22 with having -- you know, the Stern test doesn't m odel 23 exactly, you know, what we're planning o n p utting in, 24 et cetera.
25 So our initial correlation was this NSP1 NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 47 1 correlation.
And that was built off of t he Stern data 2 that we had gotten back in 2013.
3 Like I s a i d it had a g eneric n on-mixing 4 spacer grid, but it was -- the t e sting was very 5 expansive in terms of c o n d i t i ons, like very low 6 relative to where the NuScale reactor is f airly h igh, 7 you know, mass fluxes. Pressure range was very large, 8 covering almost, you k now, w ay below where a B WR w ould 9 go to until, you know, up to where a PWR w ould 10 normally be tested, things like that.
11 So it was a very thorough database, but, 12 you know, it just wasn't t he final design. So we used 13 t hat to develop this NSP1 correlation.
And th e n i n 14 early 2015, we changed fuel vendors to Framatome.
And 15 we were going with this NuFuel-HTP2 d esign, w hich 16 then had the HTP and HMP grids and that.
17 And so what we did was to make sure t hat, 18 you k now, t he correlation w e would have would work 19 with that. We were a ble to obtain a limited amount of 20 data from AREVA that was relevant.
21 And we could look at that with this NSP1 22 corr e l a t i on and w e did. And it wasn't -- the 23 correlation didn't d o a great job of predicting it 24 partly because it wasn't tuned to predict that.
25 So we developed t his NSPX factor which it NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 48 1 was intentionally designed to have conservatism. It 2 addressed the trend difference that we saw with that 3 small set of data from Framatome. And it also added 4 an intentional, you k now, like 5 p e r cent e xtra 5 conservatism.
Because the way we were w orking at the 6 time, we were going to have to be using t h e 7 correlation w hile we were in parallel getting the data 8 for the actual bundled design.
9 So we built in a lit t l e bit of risk 10 mitigation by adding conservatism. And then once we 11 actually received the data for t he NuFuel-HTP2 design 12 in 2016, we used that set of data to validate the 13 combination of NSP1 and NSPX, which is what we refer 14 to as NSP2.
15 MEMBER CORRADINI: So what is NSP4?
16 MR. BRADBURY:
I will get to t hat, I 17 believe, on the next slide.
18 MEMBER CORRADINI: Oh, sorry.
19 MR. BRADBURY: Oh, no, that's fine.
20 MEMBER SKILLMAN:
Okay. Just before we 21 change slides, NuFuel-HTP2 trademark.
22 MR. BRADBURY: Yes.
23 MEMB E R SKILLMAN:
If you will codify it 24 such that it i s m arried to t he NuScale design forever 25 and ever?NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 49 1 MR. BRADBURY:
Okay. So when y o u say 2 that, do you m e a n, would Framatome use it another 3 plant or do you mean it (simultaneous speaking)?
4 MEMBER SKILLMAN:
For any NuScale p lant 5 must the new NuScale plant use only NuFuel-HTP2 TM?
6 MR. BRADBURY:
If they are -- if t heir 7 safety analysis is performed with either the NSP2 or 8 the NSP4 correlation, than yes. Now, if we switched 9 fuel vendors 20 years from now --
10 MEMBER SKILLMAN: A whole new package.
11 MR. BRADBURY: Right. We'd have to --
12 MEMBER SKILLMAN: Re-analysis.
13 MR. BRADBURY:
Right. We'd have to get a 14 whole new correlation and such, yes.
15 MEMBER SKILLMAN:
Okay. So what w e're 16 really talking about here i s this 37 fuel assembly 17 plant with 16 control rods up to 4.9 5 percent 18 enrichment using NuFuel-HTP2 TM.
19 MR. BRADBURY:
For the CHF correlation, 20 yes. As far a s -- I'll let you jump in on the other.21 MEMBER SKILLMAN: The analogy in my mind 22 is when y ou buy a vehicle f rom a vehicle manufacturer, 23 you get a n engine, probably designed and built by that 24 manufacturer for t hat vehicle. Y o u don't get a 25 different engine.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 50 1 And so what I'm c ou p l i ng in my mind is, 2 okay, I got it. I understand what they're d oing. But 3 for the suite of analyses and for the effort that is 4 going into this, the b uyer of the first NuScale design 5 uses this fuel and only this fuel unless there's a re-6 analysis for fuel?
7 MS. WIKE: Correct.
8 MR. BRADBURY: Correct.
9 MEMBER SKILLMAN:
It seems crazy, but I'm 10 just trying to get it set in my mind. Thank you.
11 CHAIRMAN KIRCHNER:
Let me ask a different 12 question.
NSPX is t hat a co n s t a n t or a variable 13 correction?
14 MR. BRADBURY: It's a variable.
15 CHAIRMAN KIRCHNER:
Like a Tong factor, 16 then?17 MR. BRADBURY: Kind of.
18 CHAIRMAN KIRCHNER:
Has it any physical 19 bases?20 MR. BRADBURY: Yes. In developing it, I 21 think we'll get a little m ore into this in the close.22 But in developing we, you k now, looked at 23 sensitivities to various -- you know, I mean, in the 24 main frame there's a p ressure, flow, et cetera, et 25 cetera. So, you k n o w, we analyzed those t hings to NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 51 1 see, okay, you know, what seems to have t he most t rend 2 here? A nd then we picked the one tha t i t seemed to 3 have the most trend with and used that.
4 And we designed it so it's conservative.
5 Like, we added the conservatism in. We d esigned it so 6 that you'll n ever get a benefit f rom it. So it's only 7 ever t he worst -- or at be s t it's a p enalty. You 8 won't ever gain from it, I guess.
9 CHAIRMAN KIRCHNER: Now stop me if I get 10 into s omething closed, but normally, in the industry, 11 the history is the spacer grid d esigns h ave been used 12 to enhance heat transfer.
13 And typically that gives you the ability 14 to run the fuel at a higher heat flux and still have 15 a significant margin in your margin t o either, in your 16 case critical heat flux or DNB in the l arger PWRs. So 17 I'm trying to just understand your language here.
18 You were saying repeatedly that the NSPX 19 factor conservatively extends the NSP1 correlation.
20 MR. BRADBURY: Right. Okay. So to make 21 it a little clearer.
22 CHAIRMAN KIRCHNER:
Because the reason I'm 23 struggling with the v erbiage here is that NSP1 was 24 developed with, you know, the plain vanilla n on-mixing 25 grid. Once you go to your actual fuel with its nice NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 52 1 mixing veins and all of t hat in the grids, then one 2 expects b etter performance t hermo-hydraulically 3 speaking.4 MR. BRADBURY: I can discuss that. I 5 think that probably needs to be in t he closed session.6 CHAIRMAN KIRCHNER: Okay. I'll wait.
7 MR. BRADBURY:
I'm ready t o discuss it but 8-- okay. I'll take a n ote and I'll b ring it up at --9 MS. WIKE: Okay. NSP4.
10 MR. B R A D BURY: All right. The NSP4 11 correlation.
So NSP2, if you l ook at it, we developed 12 it based on the Stern data really and a small subset 13 of d ata from Framatome.
And then we validated it with 14 the NuFuel-HTP2 data. O kay. That's a n on-traditional 15 of doing it. Normally, you would --
16 MEMBER CORRADINI:
But when you say 17 validate, based on how you describe NSPX multiplying 18 NSP1 getting NSP2.
19 MR. BRADBURY: Mm-hmm.
20 MEMBER CORRADINI: It should, if I had a 21 45 deg ree line, always underpredict or predict CHF 22 before you actually saw it experimentally.
23 MR. BRADBURY: Correct.
24 MEMBER CORRADINI: Okay.
25 MR. BRADBURY:
Yes. So t he NSP2 was more NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 53 1 of a convoluted way of getting t here. And that was 2 just due to scheduling e ssentially.
NSP4 was a c lean 3 slate. You know, we developed it off of the NuFuel-4 HTP2 specific CHF data.
5 We validated it with the s ame data. It's 6 more the normal process you would expect to g o through 7 for d eveloping a CHF correlation.
So that's what the 8 NSP4 correlation is.
9 And w hat that gets us is it turned out the 10 NSP2 was very conservative.
So NSP4 helps regain some 11 of those margins for other things, you know, whether 12 it is to do something that, you know, where you have 13 to a ccommodate a higher h eat f lux or, y ou k now, 14 whatever could come up.
15 MEMBER CORRADINI:
But l e t m e a sk a 16 different question.
A nd, a gain, I'm not sure what you 17 showed o n a slide somewhere, some box somewhere, a bout 18 flow versus power.
19 MR. BRADBURY: Oh, yes.
20 MEMBER CORRADINI:
The design p oint didn't 21 change or did it?
22 MR. BRADBURY:
No. The design point does 23 not.24 MEMBER CORRADINI:
So essentially, you've 25 regained margin to be used o r t o be known, but not to NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 54 1 be changing the design that you --
2 MR. BRADBURY: Correct.
3 MEMBER CORRADINI: -- now submitted.
4 MR. BRADBURY:
Correct. Right. We w ould 5 not change a n y thing with t he D CI or a nything like 6 that.7 MEMBER CORRADINI:
Okay. Fine. T hank 8 you.9 MR. BRADBURY:
So b asically, you know, the 10 process for NSP2 was kind of convoluted.
You started 11 with one set of data. You v alidated with a different 12 set of data. And then the process for NSP4 was more 13 traditional where, you k now, you created the 14 corre l a t ion to the actual data you care about and 15 validated it as such. Okay.
16 CHAIRMAN KIRCHNER: But, again, it might 17 explain, I t hink, gets t o what I was thinkin g that 18 your terminology
-- yo u have a static design. But 19 your f inding improved w ith your -- not improved d ata. 20 With more d a t a t h at's more prototypical of your 21 design, your mar g ins are greater with the static 22 design.23 MR. BRADBURY:
Right. Given the 24 particular design, we'll call it the N SP2 correlation 25--NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 55 1 CHAIRMAN KIRCHNER: Yes.
2 MR. BRADBURY:
-- b ecause t hat's what I've 3 been calling it. That one predi c t s v ery 4 conservatively.
Like, you know, i f you pop up the CHF 5 data and you've got that 4 5 degree line, like, all of 6 it will be below it.
7 CHAIRMAN KIRCHNER: Yes.
8 MR. BRADBURY:
A n d i t's just very, very 9 conservative.
And that's fine. I mean, you k now, in 10 the R ev 0 or w hatever of t he D CA, that's what we used 11 and, you k now, we were able to survive, you k now, 12 transient scenarios.
You k now, b ut the desire was 13 there to, you know, recover margin in case things come 14 up in the future or, you know.
15 CHAIRMAN KIRCHNER:
I n case you have s pare 16 change in your pocket and you want to c ome back for an 17 upgrade.18 MR. BRADBURY:
Maybe. Something.
There's 19 lots of options where certainly m argin never h urts you 20 so that's --
21 MEMBER CORRADINI:
But I think j ust so 22 we're c l e a r , you quantified the margin. You didn't 23 change the design.
24 MR. BRADBURY:
W e did not change anything 25 in the design.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 56 1 MS. WIKE: That's correct.
2 MEMBER MARCH-LEUBA:
The thing I d on't 3 really understand on this little bit higher level is 4 why are you a sking approval f o r NSP2 if NSP4 w orks 5 just as w e l l and is much better than NSP2? Why are 6 you wasting our time?
7 MR. BRADBURY: We'll let Jennie.
8 MS. WIKE: Yes. W e l l , the answer is we 9 had originally submitted the topical report with N SP2.10 MEMBER MARCH-LEUBA:
So you worked very 11 hard on it so you're making us work hard on it?
12 MS. WIKE: We didn't want to restart the 13 review. There was a lot o f o verlap in our correlation 14 development between NSP2 and NSP4. And we wanted to 15 use t hat and so we added NSP4 to this existing 16 topical. And that's why we kept NSP2.
17 MEMBER MARCH-LEUBA: It was supplemental 18 rather than (simultaneous speaking).
19 MS. WIKE: Correct. When you see us a gain 20 for t he applicable chapters in the DCA, you'll see 21 that we use, like for example, i n C h a p t er 14, N SP4. 22 So whil e t h i s topical covers both NSP2 and NSP4, in 23 our DCA we've adopted NSP4. Next slide.
24 MR. BRADBURY:
All ri g h t. So both of 25 these correlations, NSP2 and NSP4, are implemented in NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 57 1 VIPRE. You know, VIPRE is a pretty u biquitous 2 Subchannel T/H code. It's used by nu m e r ous vendors 3 and utilities. It has the generic SER.
4 And we did, you know, d o all the use case 5 stuff. I'm not going to talk about it here because 6 that was in a separate topical r eport. That w as in 7 Subchannel Analysis Methodology Topical Report.
8 But the point is that, you know, we took 9 the g eneric S ER. We do show that it i s applicable for 10 NuScale. And then, you k now, one of the key things 11 h e r e is, you know, all of the constituent of m ode l s 12 and such that you would pick for u sing an analysis are 13 identical to what was used in the CHF development.
14 So t he CHF c orrelation i tself is acting as 15 a closure model, kind of t ying t he application back to 16 testing.17 MEMBER MARCH-LEUBA:
So, yes, honestly, 18 I'm not picking on you. I'm j ust trying t o learn. Is 19 EPRI an Appendix B supplier for you?
20 MR. BRADBURY:
EPRI i s not the -- the code 21 is owned at this point by Zachary.
22 MEMBER MARCH-LEUBA:
And they a re an 23 Appendix B supplier?
24 MR. BRADBURY: Yes.
25 MEMBER MARCH-LEUBA: Okay.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 58 1 MEMBER REMPE: Well, if they're going to 2 be o verlapped, we're going to do a separate review on 3 us i n g VIPRE f or NuScale and, I assume, each of the 4 documents r eferences c ertain of each o ther's document.5 MR. BRADBURY: Pretty much.
6 MEMBER REMPE: And if there's something 7 you6 find wron g in here, y ou'll have to update the 8 VIPRE document and vice versa. And that's the plan.
9 You'll just do a rev.
10 MR. B RADBURY: Yes. They are pretty 11 inexplicably tied.
12 MEMBER REMPE: Yes.
13 MEMBER CORRADINI:
So j ust for my memory, 14 did Zachary u sed to be Nuclear Numerical Applications?
15 MR. BRADBURY: Well, yes, that was --
16 MEMBER CORRADINI: They're renamed.
17 MR. BRADBURY:
T hat wasn't the -- who was 18 it? CSI, that's right.
19 MEMBER CORRADINI: Okay, fine.
20 MR. BRADBURY: Yes. Computer Simulation 21 something, I think.
22 MEMBER CORRADINI: Thank you.
23 MR. B R A DBURY: Okay. So effectively we 24 have two CHF correlations with the NSP2 and the NSP4 25 that we d eveloped.
We feel they're both applicable to NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 59 1 NuScale. The NSP2 is conservative, which was good in 2 some w ays. And the NSP4, you know, w e can regain 3 margins.4 You know, the topical report provides the 5 test dat a, provides the details of the correlation 6 development, provides the limits for t he correlations, 7 which tie back to GDC10. And it a lso gives the 8 applicability range and criteria.
And tha t's what 9 we're seeking approval of.
10 CHAIRMAN KIRCHNER: Okay. Any questions 11 at this point? Okay. Let's take a brief pause here 12 in situ and have the staff come up and present their 13 evaluation in open session. Go ahead, please.
14 M R. BAVOL: Okay. Thank you and go o d 15 afternoon.
My name is Bruce Bavol. I'm a project 16 manager for the NuScale project. T hese are two of my 17 topical reports that we're reviewing. Currently, we 18 completed our review on.
19 And to my right is Tim Drzewiecki.
And I 20 just wanted to let you know that per our agenda that 21 in a closed session, we are going to c over e ach t opic 22 separately to add continuity to the closed material.
23 The other contributors, Becky Karas is 24 here. S h e's a branch chief of the R eactor Systems. 25 Jeff S chmidt, who i s not. And t hen we had some NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 60 1 additional support for both the nuclear analysis and 2 CHF by Boyce Travis, Josh Kaizer and David Heeszel.
3 The timeline for the codes and the methods 4 qualification, this particular topical report, as was 5 discussed, came in on August 30, 2016. We had an RAI-6 8807 came in on May 9, 2017. We got a response back 7 from NuScale. That response was reviewed and closed 8 resolved.9 Our future plans are to have an ACRS full 10 committee s cheduled currently at June 7. It's a 11 Thursday morning. And we plan to issue a -- o ur plan 12 is to issue a final SER late 2018. And then publish 13 our approved version early October.
14 With that, I'm goin g t o turn i t o ver to 15 Tim.16 DR. DRZEWIECKI:
Thanks, Bruce. So in 17 terms of the findings made for the nuclear codes and 18 methods topical report we're not making findings, of 19 course, on any of the GDCs at this point. Those are 20 made during a DCA review.
21 But where this methodology is u sed once 22 approved, i t will f orm a partial basis for t hose 23 findings.24 What was asked for is staff t o f irst 25 approve the application of the C MS5 c ode suite for the NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 61 1 new scale core design as well as the base NRFs which 2 are t h e n umbers that a re used to a ccount for the 3 uncertainty in the prediction of those parameters as 4 well as an NRF update methodology.
5 Key areas of the staff review, and this is 6 kind o f how t he SE i s laid o ut. One is bas i c a lly 7 modeling capabilities of the CMS5 code s u ite, in 8 particular can y ou mode the appropriate geometry, the 9 material?
And do you h ave the appropriate physics 10 modeling capabilities in this code to do the job?
11 The assessment of the CMS5 code suite, and 12 that i ncludes the code-to-code comparisons as well as 13 comparisons to any kind of benchmarks a nd oper a t i ng 14 data, the NRF update methodology and development, 15 that's mostly a math problem.
16 And then the last one was t he uncertainty 17 of management during operation. And this is even if 18 you have confidence in your NRFs and your update 19 methodology, what if you're s till wrong whether you do 20 that? So that was something that we had fleshed out 21 as part of the SE.
22 Okay. So t h e a reas in which, you k now, 23 staff had spent some more time and which you would not 24 do i n a traditional review, o ne as far as the geometry 25 of this plant the fact that you have several modules NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 62 1 that are close together, we wa n t e d to ensure that 2 there was no kind of feedback from module to module, 3 especially given the location o f the ex-core 4 detectors.
5 The physics modeling, w e wanted to make 6 sure thermo-hydraulic m odeling capabilities inside of 7 SIMULATE5 w e r e appropriate.
And t his goes into 8 things, y ou know, like y our void feedback.
Make sure 9 that you can actually capture, you know, your void 10 fraction inside of SIMULATE5.
11 A validation of analysis, we made sure 12 that, you know, some of the key components here that 13 were different from a plant or t he fact that i t's a 14 small e r core, higher leakage and it's got a h eavy 15 reflector. So we made sure that they had validation 16 data that can address those aspects of this design.
17 Things staff had considered as part of 18 this review was not only the information provided in 19 this topical and obtained in the REI process as well 20 as the aud i t of the supporting c alculations, but we 21 also looked at the review of the generic CMS5 report 22 a s well as t he manuals and i nformation that w a s 23 supporting that review.
24 A l so, we h ad looked at similar types o f 25 reviews that were done in this area, like Duke Power NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 63 1 design methodology on any APS reactor physics 2 methodology.
3 So a s f a r as staff conclusions, on this 4 SER we did find the CMS5 code suite c an model the 5 NuScale c o r e design subject to one limitation.
And 6 that was that there was a l ist of materials used in 7 the core d esign that were fleshed out i n the CMS5 8 generic review. And they are going to be limited to 9 those same limitations here obviously.
10 But other than that, they are not 11 particularly wedded t o a design t hat would have, l ike, 12 an M5 cladding.
If t hat were to change in the future, 13 they would n ot be bound by this t opical t o use M5. 14 The base NRFs --
15 CHAIRMAN KIRCHNER: May I interrupt you, 16 Tim, just on the public record, limitation to 17 materials.
Now, if I recall, CMS5 is using ENDF/VII, 18 whatever mod.
19 DR. DRZEWIECKI: That's right, yes.
20 CHAIRMAN KIRCHNER:
So I w ould assume 21 that's all encompassing of the ma t e r i als that are 22 being modeled or are t here o ther m aterials in this 23 design that that cross-section database doesn't cover?24 D R. DRZEWIECKI:
So it's not limited b y 25 the cross-section so much as the closure of equations NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 64 1 that are being used to m odel some o f the mater i a ls 2 inside of SIMULATE5. Because SIMULATE5 does account 3 for things like fuel burn-up and change in the thermal 4 conductivity.
It accounts for things like changes in 5 geometry from swelling. And those have an impact on 6 reactivity.
And because o f those equations, is why --7 CHAIRMAN KIRCHNER:
S o it's more in 8 reference to the SIMULATE5 --
9 DR. DRZEWIECKI: Yes.
10 CHAIRMAN KIRCHNER:
-- not the b asic 11 neutronics. Thank you.
12 DR. DRZEWIECKI:
S ure. Okay. The second, 13 which i s the base o f N RF's proposed are accept a b l e. 14 And going back to one question that was s tated before, 15 the base NRFs all a ccount f or more uncertai n t y than 16 the generic CMS5 NRFs.
17 And last is that the NRF update 18 methodology t h a t was proposed in its topical report 19 are acceptable subject to one l imitation and the 20 condition.
21 And one limitati o n was that a ny kind of 22 updates to of a delayed neutronic parameter cannot 23 reduce its magnitude at below 5 percent. And that's 24 based on the data that we had seen. It was kind of 25 limited to tha t. So we couldn't see -- I mean we NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 65 1 could get it lower than that.
2 And the one condition is t hat any updates 3 to t he peaking factors, they must account for the pin-4 to-box bias and fixed in-core dete c t or bias in 5 accordance with the generic CMS5 topical report.
6 CONSULTANT SCHULTZ: Tim, that condition 7 is there because more information needs to come in 8 during operation in order for the overall evaluation 9 to be complete in these areas?
10 DR. DRZEWIECKI: You mean as far as this 11 condition for the peaking factors?
12 CONSULTANT SCHULTZ: Yes. This is 13 provided because there wasn't sufficient information 14 based upon lack of operation of the NuScale 4.
15 DR. DRZEWIECK I: N o. It has to do with 16 how these f actors were generated in the g e n e r ic 17 methodology in the sense that w hen you come up with a 18 pin-to-box bias, that has two factors in there.
19 One is a comparison of CASMO5 to MCNP6 --20 I'm sorry, actually, no. One of the benchmarking of 21 the CASMO5 code to data to basically see how that code 22 actually c ompares against data a nd the other was a 23 SIMULATE5 to CASMO5 t o l ook at t h e uncertainty that 24 you impose for your p in power reconstruction 25 algorithm.
Those are fixed values that you really NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 66 1 can't reduce by getting more data. And t hose were set 2 by the code vendor. And so we a re requiring that 3 those be maintained.
4 M E M B ER CORRADINI:
Oh, I got y ou. It's 5 the bias that you're maintaining.
6 DR. DRZEWIECKI: That's right.
7 MEMBER CORRADINI:
As whatever new data 8 will move the performance, y o u want t o m aintain the 9 bias, if I understood the condition.
10 DR. DRZEWIECKI:
That's right. That's 11 right. Y es. And there's also a bias associated with 12 having a fixed core i nstrumentation system, w hich 13 affects your 3D power peaking factor.
14 CONSULTANT SCHULTZ: All right. So in 15 spite of w hat might be developed in the future by 16 NuScale, the obligation is to meet condition one?
17 DR. DRZEWIECKI: That's right.
18 CONSULTANT SCHULTZ: Thank you.
19 MR. BAVOL: Okay. We're going move on to 20 the critical h eat flux, the s taff r eviewed time l ine. 21 This particular topical report Rev 0 was updated to 22 Revision 1. The r e v ised submittal implements the 23 additional NSP4 critical heat flux correlation and 24 incorporates changes associated with the RAIs that 25 this staff had submitted to point.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 67 1 There were two k ey RAIs. R AI-8795 and 2 RAI-8931.
ML numbers a re provided.
T hose two are as 3 responded to, completed, resolved and s atisfactorily.
4 The s taff p lans to also have an advisory committee 5 represen t t he safeguards at full committee J une 7, 6 same time. W e'd like t o h ave an issue o f a final SER 7 late July 2018 and publish the a pproved version of the 8 topical report also in October 2018.
9 DR. DRZEWI E C K I: So similar t o t he last 10 topical report, we are not making findings again st 11 specific GDCs here and approve the CHF topical report 12 can b e u sed to establish a partial basis, which is 13 used in review of the DCA to m ak e findings against 14 things l ike GDC10, 12 as well as any kin d of 15 omnivaluation of accidents looking at t hose 16 consequence of analyses.
17 NuScale had requested this review go 18 through and approve the use of NSP2 and NSP4, the CHF 19 correlations for the safety analysis o f NuScale p ower 20 module w ith NuFuel-HTP2 f uel over a s pecified range of 21 applications and with specific CHFR limits.
22 Key areas of staff review, of c ourse, was 23 d a t a collection, CHF model generation and a l arg e 24 focus of this review was on quantification of the CHF 25 model error, which is how you come up with your CHFR NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 68 1 limits.2 Areas in which the staff spent more time 3 was o n the development of a 95/95 CHFR limits as well 4 as we did look closer at the correlation of behavior 5 because its trends was s omewhat d ifferent from what we 6 had s een in the traditional P WR. And so we wanted to 7 make sure that we understood w hy we were s eeing t hat, 8 or a t least, you know, k now that t here was enough data 9 to back up those trends.
10 I think the staff had considered obviously 11 the information in t his to p i cal as well as the RAI 12 responses in the audit of the supporting calculations.
13 There was an inspection done at S tern 14 Laboratories for 20 1 3 when we w ere collecting d ata. 15 There was also a program, a report, that was submitted 16 to the staff in 2 0 14, preapp l ication space, that 17 pretty much had laid out what their program was g oing 18 to look l ike, where they e xpect in terms of what kind 19 of flow rates and pressures they expect to see in 20 their transient and accident analyses as w ell as t here 21 was an a udit done of a KATHY facil i t y in 2016. And 22 then, of course, the information t hat w as obtained 23 from previously reviewed CHF correlations.
24 And as part of this S E, there was an 25 appendix that kind of lays o u t t he review framework NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 69 1 that was informed by several o f the past C HF reviews.2 MEMBER REMPE: S o I'll ask you the same 3 question I asked the applicant about the data and when 4 instrumentation goes bad and what you've seen in the 5 past with your reviews of Stern data and KATHY data.
6 Again, you know, have t hey had some errors where they 7 detected i t? And how was that detected and how was it 8 replaced, the c ensors replac e d and how were they 9 qualified?
10 DR. DRZEWIECKI:
S o I have not seen issues 11 with them seeing failures in their, you k now, in t heir 12 calibrated instrumentation.
13 Something that does give us confidence is 14 both at Stern and at KATHY, they d o repeat test points 15 to e nsure that they can get, you k now, the same points 16 over and over again. Now the way it's done at Stern 17 and KATHY are different.
And that's fleshed out some 18 in the closed session. I can explain how that's done 19 at both facilities.
20 MEMBER REMPE: Okay.
21 DR. DRZEWIECKI: And so if they fell out 22 of calibration, there are certain reference points 23 where they should be a ble to go b ack and check and see 24 that they're still getting the results.
25 MEMBER REMPE: I'd be interested. Thank NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 70 1 you.2 DR. DRZEWIECK I: Okay. So the staff of 3 SER c onclu s i o ns is that the NSP2-CHF correlation is 4 acceptable for use in performing the safety analysis 5 of NuScale power module with NuFuel-HTP2 fuel with a 6 limit of 1.17 over a range of applicability provided 7 in the table, in that topical report, subject to two 8 limitations.
9 Similarly, the NSP4 correlation is also 10 acceptable for use with a limit of 1.12 over a range 11 of applicability, which a re p rovided i n the topical as 12 well.13 Those two limitations a re that the non-14 uniform flux factor s , or your Tong factors, h ave to 15 always be greater than or equal to one. Basically, it 16 has to always be -- it can't b e a credit t o CHF 17 margin. It's always applied as a penalty.
18 And that the use o f these correlations 19 have to be used in accordance with the Subchannel of 20 Analysis Methodology to b e used i n accordance with the 21 validation of these CHF correlations.
22 MEMBER CORRADINI:
W hich is a separate 23 topical we'll see.
24 DR. DRZEWIECKI:
Yes. That's right. 25 Acceptable topical we'll see.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 71 1 MEMBER CORRADINI:
So, I mean, that m akes 2 sense. I'm just trying to find out how t his is 3 linked. So how can one a gree to use the CHF 4 correlation until we see t he subchannel analysis.
5 They seem inextricably linked.
6 DR. DRZEWIECKI:
W ell, they are linked. 7 The important thing is that t he models used for all of 8 the d ata reduction calculati o n s are frozen. That's 9 the important thing.
10 That's what w e want to do i s to ensure 11 t h at t hose models and those code options are f roz e n 12 whic h is, you know, that's what's l aid out in that 13 subchannel analysis methodology. And so, basically, 14 when you do any kin d o f subchannel calculation, you 15 know, you have confidence that you're going to get the 16 same kind of -- yes.
17 MEMBER CORRADINI:
And then the next 18 question i s so, as I understand the limitation, if 19 used w ith an approved subchannel analysis methodology, 20 NuScale can apply either to or for?
21 DR. DRZEWIECKI: That's right.
22 MEMBER CORRADINI: Okay.
23 MR. B A Z OL: And that concludes o ur open 24 part of the presentation.
25 CHAIRMAN KIRCHNER: Okay. Any questions NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 72 1 from the members at this point? Let us then turn to 2 any c omments f rom the p ublic and see i f there are any 3 me m b e rs of the public that wish to make a comment? 4 I'm not seeing any present.
5 Can we -- yes, I know. We'll wait for the 6 bridge line t o be opened a nd see if any members of the 7 public are out there. If there a re any members of the 8 public listening in, and if you wish to m ake a 9 comment, please identify yourself and make that 10 comment. Hearing none, we can c lose the b ridge l ine, 11 please.12 And with that, I propose that w e t ake a 13 break at this point. I assume that we'll have 14 comments from the committee and our consultant after 15 the closed s ession. So with that w e a r e recessed.
16 Let's come back at quarter of on that clock.
17 (Whereupon, the open s ession of the matter 18 went off the record at 2:31 p.m.)
19 20 21 22 23 24 25 NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 PM-0518-59766-P 1 Copyright 2018 by NuScale Power, LLC.
Revision: 0 Template #: 0000
-21727-F01 R3 NuScale Nonproprietary Nuclear Analysis Codes and Methods Qualification TR-0616-48793 ACRS Presentation Allyson Callaway Chris Kirby Vick Nazareth ACRS Open Session - May 15, 2018 PM-0518-59766-P 2 Copyright 2018 by NuScale Power, LLC.
Revision: 0 Template #: 0000
-21727-F01 R3 This material is based upon work supported by the Department of Energy under Award Number DE
-NE0000633.
This report was prepared as an account of work sponsored by an agency of the United States (U.S.) Government. Neither the U.S.
Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the U.S.
Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the U.S.
Government or any agency thereof.
Acknowledgement & Disclaimer
PM-0518-59766-P 3 Copyright 2018 by NuScale Power, LLC.
Revision: 0 Template #: 0000
-21727-F01 R3 T Agenda *Overview*Code Description
- Core and Reflector Description
- Code Validation
- Nuclear Reliability Factor Generation
- Applications
- Summary PM-0518-59766-P 4 Copyright 2018 by NuScale Power, LLC.
Revision: 0 Template #: 0000
-21727-F01 R3 T Overview *NuScale seeks NRC approval to use StudsvikScandpower's Core Management Software (CMS5) codesuite for the nuclear physics design and analysis of theNuScale reactor*Code suite has been benchmarked for NuScale application*Nuclear reliability factors (NRFs) have been generated to
ensure conservative application for downstreamcalculations
- Codes have been validated to generate nuclear physics
parameters for use in core design, safety analysis, startuptesting, and operations support PM-0518-59766-P 5 Copyright 2018 by NuScale Power, LLC.
Revision: 0 Template #: 0000
-21727-F01 R3 Code Description
- CMS5 code suite includes:CASMO5 *Lattice physics code (ENDF/B
-VII.1)*Uses multi
-group 2D/3D neutron transportSIMULATE5 *Core simulator
- Uses 3D steady-state, multi
-group, nodaldiffusion theoryCASMO5/SIMULATE5 is the latest Studsvik neutronics code suite version
- Earlier and latest versions of this code suiteare widely used in the nuclear industry forcore physics calculations PM-0518-59766-P 6 Copyright 2018 by NuScale Power, LLC.
Revision: 0 Template #: 0000
-21727-F01 R3 T Core, Fuel, & CRA Description Core Description Power Level, MWt 160 Number of Fuel Assemblies 37 Number of Control Rod Assemblies 16 Fuel Assembly Description Fuel Rod Array17x17 Number of Guide Tubes 24 Number of Instrument Tubes 1 Fuel Rod Description Material UO 2Maximum Enrichment, wt% 4.95 Clad Material M5 Active Fuel Length, in. (cm) 78.74 (200)
Control Rod Assembly Description
Clad Material Stainless Steel Poison Material AIC, B 4C Integral Burnable Poison Description
Absorber Material Gd 2 O 3 PM-0518-59766-P 7 Copyright 2018 by NuScale Power, LLC.
Revision: 0 Template #: 0000
-21727-F01 R3 T Core Radial Reflector Radial Reflector Core Barrel Cooling Channels
PM-0518-59766-P 8 Copyright 2018 by NuScale Power, LLC.
Revision: 0 Template #: 0000
-21727-F01 R3 CMS5 Validation Flow Chart
PM-0518-59766-P 9 Copyright 2018 by NuScale Power, LLC.
Revision: 0 Template #: 0000
-21727-F01 R3 T Code-to-Code Benchmarking
- CMS5 code-to-code comparisons are performed withMCNP6-MCNP is considered a hi gher-fidelity c ode-MCNP6 model is both detailed and specific to NuScale design-Parameters benchmarked with this process include keff, peaki ng factors, power distribution, critical boron concentration, reactivitycoefficients, and control rod worth
-Data from code-to-code comparisons consists of tens to hundredsof data points for each parameter being examined
-Data points represent either an absolute or relative differenc e between CMS and MCNP PM-0518-59766-P 10 Copyright 2018 by NuScale Power, LLC.
Revision: 0 Template #: 0000
-21727-F01 R3 T Empirical Benchmarking
- Empirical benchmarking by code simulation of criticality data and comparing it to data results
- Types of Data
-Critical Experiment Data
-Experimental Reactor Data
-Commercial Reactor Critical Data*Parameters benchmarked with this process include keff , power distribution, critical boron concentration, reactivitycoefficients, and control rod worth PM-0518-59766-P 11 Copyright 2018 by NuScale Power, LLC.
Revision: 0 Template #: 0000
-21727-F01 R3 T Commercial Data Benchmarking
- Commercial Data Benchmarking
-Use available and relevant operating data to demonstrate ability t o accurately predict neutronics parameters with CMS5, as no NuScale-specific operating data exists
- TMI-1 Cycles 1 & 2 were modeled with CMS5 suite
-Comparisons were made between actual operating data and CMS5 predictions
-Important neutronics parameters were compared to derive biases and uncertainties
- Results from commercial data benchmarks, empiricalbenchmarks, and higher
-fidelity code comparisons areused to determine bias and bias uncertainties, and in turndevelop NRFs for NuScale applications of CMS5 PM-0518-59766-P 12 Copyright 2018 by NuScale Power, LLC.
Revision: 0 Template #: 0000
-21727-F01 R3 T Reliability Factor Generation
- The benchmarking data discussed previously was used to determine bias and bias uncertainties
- Develop a set of conservative factors called Nuclear
Reliability Factors (NRFs) for initial use in the NuScaledesign*NRFs will be validated and updated during the startup
testing process and module operation PM-0518-59766-P 13 Copyright 2018 by NuScale Power, LLC.
Revision: 0 Template #: 0000
-21727-F01 R3 T CMS5 Application
- CMS5 is used to perform core physics calculations for multiple applications in the NuScale modules:
-Designing and optimizing the nuclear core for initial core and reloads-Providing input parameters for design basis safety analysis
-Generation of startup physics testing predictions
-Generation of core follow predictions
-Developing plant physics data books PM-0518-59766-P 14 Copyright 2018 by NuScale Power, LLC.
Revision: 0 Template #: 0000
-21727-F01 R3 T Summary *NuScale has demonstrated acceptability of Studsvik'sCMS5 code suite for the nuclear design and analysis ofthe NuScale design.*Code qualification is supported by benchmarking againstcritical experiments, experimental reactors, commercial reactor data, and a higher
-fidelity code.
- Q ualification has resulted in the determination of conservative NRFs for use in the NuScale analyses.
- Physics parameters generated using this code suite willbe used in core design, safety analysis, startup testing,core follow and operations.
PM-0518-59766-P 15 Copyright 2018 by NuScale Power, LLC.
Revision: 0 Template #: 0000
-21727-F01 R3 Portland Office 6650 SW Redwood Lane, Suite 210 Portland, OR 97224 971.371.1592 Corvallis Office 1100 NE Circle Blvd., Suite 200
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Presentation to the ACRS Subcommittee Staff Review of NuScale Topical ReportsTR-0616-48793, REV 0,"NUCLEAR ANALYSIS CODES AND METHODS QUALIFICATION"
& TR-0116-21012, REV 1"NUSCALE POWER CRITICAL HEAT FLUX CORRELATIONS "Presenters: Bruce Bavol
-Project Manager, Office of New ReactorsTimothy Drzewiecki, Ph.D.-Reactor Systems Engineer, Office of New ReactorsMay 15, 2018(Open Session)Non-Proprietary 1
NRC Technical Review Areas/Contributors 2Non-ProprietaryReactor Systems NRO/DSRA/SRSB:Rebecca Karas (BC) Jeffrey Schmidt Timothy Drzewiecki Additional Support on Nuclear Analysis MethodologyBoyce Travis, NRO/DSRA/SCVBAdditional Support on CHF:Joshua Kaizer, NRR/DSS/SNPBDavid Heeszel, NRO/DSEA/RGS Staff Review Timeline TR-0616-48793, "Nuclear Analysis Codes and Methods Qualification"NuScale submitted its Topical Report (TR) TR
-0616-48793,"Nuclear Analysis Codes and Methods Qualification", on August30, 2016 (AgencywideDocuments Access and ManagementSystem (ADAMS) Accession No. ML16243A517), assupplemented by letter dated July 6, 2017 (ADAMS Accessio n No. ML17187B240
).Staff issued request for additional information (RAI 8807) on May 9, 2017NuScale responded to RAI 8807 on July 6, 2017 (ADAMSAccession No. ML17187B239)Staff plans to brief advisory committee on reactor safeguards(ACRS) fullcommittee on June 7, 2018Staff plans to issue its f inal SER in late July 2018Staff plans to publish the "-A" (approved) version of the TR inearly October 2018 3Non-Proprietary Scope of the Staff Review*Regulatory Basis
-An approved nuclear analysis methodology is used to establish a partial basis for compliance with several general design criteria (GDC) of 10 CFR 50, Appendix A
- Applicant requested approval of:
1.Applicability of Studsvik Scandpower, Inc. (Studsvik), Core Management Software, Version 5
suite (CMS5) to the NuScale reactor core design (RXC) 2.Base nuclear reliability factors (NRFs) 3.NRF update methodology
- Key areas of NRC staff review:
-Geometric, Material, and Physics modeling capabilities of CMS5 (applicability to NuScale RXC)
-Assessment of CMS5 suite (code
-to-code and empirical data
)-NRF development and update methodology
-Uncertainty management during operation 4Non-Proprietary Scope of the Staff Review (cont)
- Areas requiring additional review (due to unique design features)
-Geometry Modeling: Multi
-module effects and modeling of heavy reflector
-Physics Modeling: Thermal
-hydraulic modeling capabilities in SIMULATE5
-Validation analyses to address high leakage cores and heavy reflectors
- Information considered by NRC staff:
-TR-0616-48793, "Nuclear Analysis Codes and Methods Qualification," and supportinginformation obtained via RAIs and audit of supporting calculations
-Documentation provided by Studsvik in support of generic CMS5 topical report
- SSP-14/P01-028-TR-NP, "Generic Application of Studsvik Scandpower Core ManagementSystem to Pressurized Water Reactors" (ML15355A285)
- CASMO5, SIMULATE5, CMSLINK5 manuals
-Similar topical reports/safety evaluations (Duke Power Company Nuclear Design Methodology, Arizona Public Service Company PWR Reactor Physics Methodology) 5Non-Proprietary Staff SER Conclusions 1.CMS5 code suite is applicable to the NuScale RXC design, subject to Limitation 1:
-Limitation 1: Application of TR
-0616-48793 is limited to the materials identified in thesafety evaluation for the generic CMS5 methodology 2.The base NRFs proposed in TR
-0616-48793 are acceptable 3.The NRF update methodology proposed in TR
-0616-48793 is acceptable
, subject to Limitation 2 and Condition 1
-Limitation 2: Updates to any delayed neutron parameter NRF cannot reduce the magnitude of the NRF below 5 percent
-Condition 1: Updates to the pin peaking NRFs (FHand F Q) must include the pin
-to-box biasand fixed in
-core detector bias in accordance with the generic CMS5 topical report.
6Non-Proprietary Staff Review Timeline TR-0116-21012, Revision 1, "Critical Heat Flux Correlations" NuScale submitted its Topical Report (TR) TR-0116-21012, Revision 1, "CriticalHeat Flux Correlations," on November 30, 2017 (AgencywideDocumentsAccess and Management System (ADAMS) Accession No. ML17335A089), thisrevision replaced the submittal dated October 5, 2016 (ADAMS Accession No.ML16279A363), "NuScalePower Critical Heat Flux Correlation NSP2."The revised submittal implements an additional NSP4 critical heat flux (CHF) correlation a nd incorporates changes associated with NRC requests for additional information (RAIs
).Staff issued two requests for additional information (RAI 8795 on May 8, 2017
-ADAMS Accession No. ML17128A468) and (RAI 8931 on August 21, 2017 -ADAMS Accession No. ML17233A127)NuScale responded to RAI 8795 on (July 7, 2017 -ADAMS Accession No.ML17188A461) and RAI 8931 on (September 25, 2017
-ADAMS Accession No.ML17268A385)Staff plans to brief advisory committee on reactor safeguards (ACRS) fullcommittee on June 7, 2018Staff plans to issue its f inal SER in late July 2018Staff plans to publish the "-A" (approved) version of the TR in early October 2018 7Non-Proprietary Scope of the Staff Review*Regulatory Basis
-An approved critical heat flux (CHF) correlation is used to establish a partial basis for compliance with several regulations including the general design criteria (GDC) of 10 CFR 50,Appendix A:
- GDC 10 and GDC 12 (margin to fuel design limits), 10 CFR 52.47(a)(2)(iv) and GDC 19 (radiological consequences)
- Applicant requested approval of:
-Use of NSP2 and NPS4 CHF correlations for the safety analysis of the NuScale Power Module
- NuFuel-HTP2 TMfuel*Over a specified range of applicability
- With specified CHF ratio (CHFR) limits
- Key areas of NRC staff review:
-Collection of experimental data
-CHF model generation
-Quantification of CHF model error (development of CHFR limits) 8Non-Proprietary Scope of the Staff Review (cont)
- Areas requiring additional review
-Statistical Analysis -
Development of the 95/95 CHFR limits
-Correlation behavior differs from trends observed in previously reviewed CHF correlations for pressurized water reactors
- Information considered by NRC staff:
-TR-0116-21012, Revision 1, "NuScale Power Critical Heat Flux Correlations," and supportinginformation obtained via RAIs and audit of supporting calculations
-Inspection report for CHF testing at Stern Laboratories, April 18, 2013
-NuScale CHF test program technical report, January 24, 2014-Audit report for CHF testing at KATHY, August 12, 2016
-Information obtained from previously reviewed CHF correlations as documented in
Appendix A of the staff's SE 9Non-Proprietary Staff SER Conclusions
- NSP2 CHF correlation is acceptable for use in performing safety analyses of the NPM with NuFuel-HTP TMfuel-W ith a CHFR limit of 1.17
-Over the range of applicability provided in Table 8
-2 of TR-0116-21012, Rev. 1
-Subject to Limitation 1 and Limitation 2
- NSP4 CHF correlation is acceptable for use in performing safety analyses of the NPM with NuFuel-HTP TMfuel-With a CHFR limit of 1.21-Over the range of applicability provided in Table 8-4 of TR-0116-21012, Rev. 1
-Subject to Limitation 1 and Limitation 2*Limitations
-Limitation 1:
N onuniformflux factors must always be greater than or equal to 1
-Limitation 2: CHF analyses using the NSP2 and NSP4 correlations must be performed i n accordance with TR
-0915-17564, "SubchannelAnalysis Methodology" 10Non-Proprietary Questions/comments from members of the public before the closed session starts?