ML20115E457
| ML20115E457 | |
| Person / Time | |
|---|---|
| Issue date: | 04/09/2020 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| Burkhart, L, ACRS | |
| References | |
| NRC-0871 | |
| Download: ML20115E457 (122) | |
Text
Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION
Title:
Advisory Committee on Reactor Safeguards Open Session Docket Number:
(n/a)
Location:
teleconference Date:
Thursday, April 9, 2020 Work Order No.:
NRC-0871 Pages 1-82 NEAL R. GROSS AND CO., INC.
Court Reporters and Transcribers 1323 Rhode Island Avenue, N.W.
Washington, D.C. 20005 (202) 234-4433
NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 www.nealrgross.com 1
1 2
3 DISCLAIMER 4
5 6
UNITED STATES NUCLEAR REGULATORY COMMISSIONS 7
ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 8
9 10 The contents of this transcript of the 11 proceeding of the United States Nuclear Regulatory 12 Commission Advisory Committee on Reactor Safeguards, 13 as reported herein, is a record of the discussions 14 recorded at the meeting.
15 16 This transcript has not been reviewed, 17 corrected, and edited, and it may contain 18 inaccuracies.
19 20 21 22 23
1 UNITED STATES OF AMERICA 1
NUCLEAR REGULATORY COMMISSION 2
+ + + + +
3 672ND MEETING 4
ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 5
(ACRS) 6
+ + + + +
7 OPEN SESSION 8
+ + + + +
9 THURSDAY 10 APRIL 9, 2020 11
+ + + + +
12 TELECONFERENCE 13
+ + + + +
14 The Advisory Committee met via 15 teleconference at 8:30 a.m.,
Matthew
- Sunseri, 16 Chairman, presiding.
17 18 COMMITTEE MEMBERS:
19 MATTHEW W. SUNSERI, Chairman 20 JOY L. REMPE, Vice Chairman 21 WALTER L. KIRCHNER, Member-at-Large 22 RONALD G. BALLINGER, Member 23 DENNIS BLEY, Member 24 CHARLES H. BROWN, JR. Member 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
2 VESNA B. DIMITRIJEVIC, Member 1
JOSE MARCH-LEUBA, Member 2
DAVID A. PETTI, Member 3
PETER RICCARDELLA, Member 4
5 DESIGNATED FEDERAL OFFICIAL:
6 LARRY BURKHART 7
MIKE SNODDERLY 8
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
3 ALSO PRESENT:
1 STEPHEN BAJOREK, RES 2
MARGARET ELLENSON, Kairos Power 6
DARRELL GARDNER, Kairos Power 7
PETER HASTINGS, Kairos Power 8
ALAN KRUIZENGA, Kairos Power 9
STEWART MAGRUDER, JR., NRR 10 SCOTT MOORE, Executive Director, ACRS 11 QUYNH NGUYEN, ACRS 12 DREW PEEBLES, Kairos Power 13 PER F. PETERSON, Kairos Power 14 JOHN PRICE, Kairos Power 15 BRIAN SMITH, NSIR 16 NICOLAS ZWEIBAUM, Kairos Power 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
4 CONTENTS 1
Call to Order and Opening Remarks........
5 2
Kairos Advanced Reactor Design -- Scaling 3
Methodology and Reactor Coolant 4
Topical Reports................. 12 5
Kairos Power Presentation......... 14, 44 6
NRC Staff Presentation
............ 36 7
Adjourn..................... 82 8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
5 P R O C E E D I N G S 1
8:30 a.m.
2 CHAIRMAN SUNSERI: Good morning. The 3
meeting will now come to order. This is the second 4
day of the 672nd meeting of the Advisory Committee on 5
Reactor Safeguards.
6 I am Matthew Sunseri, the Chair of the 7
ACRS. We are going to do a roll call of the members.
8 As I call on each member, I ask that you acknowledge 9
your presence.
10 Ron Ballinger?
11 MEMBER BALLINGER: I'm here.
12 CHAIRMAN SUNSERI: Dennis Bley?
13 MEMBER BLEY: Here.
14 CHAIRMAN SUNSERI: Charles Brown?
15 MEMBER BROWN: Here.
16 CHAIRMAN SUNSERI: Vesna Dimitrijevic?
17 MEMBER DIMITRIJEVIC: Here.
18 CHAIRMAN SUNSERI: Walt Kirchner?
19 MEMBER KIRCHNER: Present.
20 CHAIRMAN SUNSERI: Jose March-Leuba?
21 MEMBER MARCH-LEUBA: Here.
22 CHAIRMAN SUNSERI: Dave Petti?
23 MEMBER PETTI: Here.
24 CHAIRMAN SUNSERI: Joy Rempe?
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
6 VICE CHAIR REMPE: Here.
1 CHAIRMAN SUNSERI: Pete Riccardella?
2 MEMBER RICCARDELLA: Present.
3 CHAIRMAN SUNSERI: And myself, Matt 4
Sunseri. And I note we have a quorum.
5 The Designated Federal Official for this 6
meeting is Mr. Weidong Wang.
7 Today during our meeting the Committee 8
will consider the following: Item No. 1, Kairos 9
Advanced Reactor Design, specifically the Scaling 10 Methodology and Reactor Coolant Topical Report.
11 And then we will have preparation of ACRS 12 reports on those topics and several of the NuScale 13 topics that we reviewed yesterday. As reflected in 14 the agenda, portions of the NuScale section may be 15 closed in order to discuss and protect information 16 designated as sensitive and proprietary, and I believe 17 that may go as well for Kairos Power.
18 At this point, I would like to ask Scott 19 Moore, Executive Director, to add some additional 20 comments regarding today's agenda.
21 Scott?
22 MR. MOORE: Thank you, Chairman Sunseri.
23 So, a few administrative comments for 24 everybody. One is for everybody. There's an error in 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
7 the public agenda that was placed on the public 1
website. It shows lunch is going from 12:00 noon 2
until 2:00 p.m. In fact, we're going to return from 3
lunch at 1:00 p.m. today. We had been planning some 4
training for the members of the Committee from 1:00 to 5
2:00, but that's not going to take place. So we will 6
be returning at 1:00 p.m. today.
7 The second message is for the members.
8 Weidong, the DFO, will be providing you with the link 9
that you will be going to for the closed meeting in 10 your email right after I've made this announcement.
11 So please watch your emails for that link. And you'll 12 get very clear direction on when we are closing the 13 open meeting and going to the closed meeting.
14 Weidong, is that correct?
15 MR. WANG: Correct. In particular, this 16 is for letter writing only. For the meeting here, if 17 there's a proprietary question asked, then we can use 18 the Skype line. The plan was open, but, in case if 19 there's a closed proprietary question that needs to be 20 asked, then we will make it at the end of this 21 meeting.
22 Thank you.
23 MR. MOORE: Sure. So, stay in the open 24 meeting until you get directions to go to closed. And 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
8 then, if we need to go to closed, your directions will 1
be in your emails.
2 The third item is just an open reminder to 3
the public that, per the agenda that's already out 4
there, if we do go to closed, we can come back to the 5
open public line, the line that we're on right now, at 6
any time during the agenda. So, we may have to go 7
back and forth between open and closed, but that's 8
just a reminder that we may come back to open at any 9
time after we're in closed.
10 PARTICIPANT: Scott?
11 MR. MOORE: Yes?
12 PARTICIPANT: Sorry for the interruption, 13 but Larry Burkhart is reporting that there's nothing 14 on the public phone. Right now he can't hear.
15 MR. MOORE: So, Chairman, obviously, some 16 of this is for the public. So, we need to wait until 17 they can hear.
18 CHAIRMAN SUNSERI: Understood.
19 MR. BURKHART: Yes, this is Larry. I am 20 on the phone bridge and I cannot hear anything on the 21 phone bridge still.
22 MR. MOORE: Okay. Larry, can you let us 23 know as soon as you can hear?
24 MR. BURKHART: Yes, sir.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
9 MR. MOORE: Larry, are you on both lines?
1 MR. BURKHART: I am on Skype, Meetings 2
with Skype, and then listening in on the phone bridge, 3
yes.
4 MR. MOORE: Okay. Thomas is working on 5
it.
6 (Pause.)
7 MR. MOORE: This is Scott. Is the phone 8
bridge up yet?
9 MR. BURKHART: This is Larry. I can hear 10 you now.
11 (Pause.)
12 MR. MOORE: Okay. Can I go? Can the 13 public line hear?
14 MR. BURKHART: I can hear you on the 15 public phone bridge, yes.
16 MR. MOORE: Okay. Then, Chairman Sunseri, 17 I'm going to go back and repeat just a couple of 18 things.
19 CHAIRMAN SUNSERI: Just the stuff that was 20 relevant to the public, please.
21 MR. MOORE: Yes, sir. Okay. The first 22 thing was, for the public, there's an error in the 23 public agenda. We will return after lunch at 1:00 24 p.m.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
10 I'd asked that everybody on the line mute 1
their phones because we're getting a lot of background 2
noise.
3 So, we're returning at 1:00 p.m. today.
4 The members were going to have training between 1:00 5
and 2:00 p.m.; the public agenda shows 2:00 p.m.
6 That's incorrect. We're returning at 1:00 p.m.
7 Eastern today.
8 The other is just a reminder to the public 9
that we can come back to this public line at any time.
10 We may have to go to a closed line for proprietary 11 information, but, as the agenda shows, we would come 12 back to this public line for open meeting at any time 13 during the agenda.
14 Chairman, that's it for me. Thank you.
15 CHAIRMAN SUNSERI: Thank you, Scott.
16 Okay. So, all that business about the public line, 17 there will be an opportunity for the public to 18 comment. And we have set aside time in the agenda for 19 comments from members of the public attending or 20 listening to our meeting. Written comments may also 21 be forwarded to Mr. Weidong Wang, the Designated 22 Federal Official.
23 A transcript of the open portion of the 24 meeting is being kept, and it is requested that the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
11 speakers identify themselves so that the transcriber 1
can relate your comments.
2 Finally, as I reflect on yesterday's 3
session, I note that all participants did a nice job 4
of practicing good virtual meeting behaviors. Before 5
we start today, I just want to reemphasize a few, the 6
first one being how important it is to mute your 7
microphone. It becomes very difficult to hear the 8
presenters and other people that have speaking rights, 9
if you will, when there's background noise and open 10 mics that people aren't using to speak.
11 Presenters yesterday did a nice job of 12 pausing to allow member interaction. I thought the 13 interaction was good. So, please continue to pause 14 during the slides or your presentation periodically to 15 let members interact.
16 And the last point is we have this IM 17 messaging panel for those participating on the Skype 18 session. And I noted yesterday that, as the day went 19 on, people became more comfortable and more proficient 20 at using this. So I just want to remind people not to 21 post any technical sidebar discussions out there 22 because any such discussion would be out of the public 23 record. And we don't want that to happen. We want 24 everything to be transparent. So, I didn't see 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
12 anything yesterday, but, as we become more proficient 1
at using it, I just want to remind everybody about 2
that.
3 So, at this point, we are ready to pick up 4
the agenda. Yes, okay, here we are. So, we will 5
begin with the Kairos Advanced Reactor design. I'm 6
going to ask Dave Petti if he has any opening remarks, 7
as Subcommittee Chair.
8 MEMBER PETTI: No, none at this time, 9
Matt. Let's just get into it.
10 CHAIRMAN SUNSERI: Okay. All right. So, 11 I don't have any other notes. I guess I turn this now 12 over to NRC staff, is that right? Or straight to 13 Kairos?
14 MR. SMITH: This is Brian Smith. I was 15 going to do some opening remarks for the NRC staff.
16 CHAIRMAN SUNSERI: Okay. Thank you, 17 Brian. I appreciate that. I didn't have that in my 18 notes. So I apologize. Please go ahead.
19 MR. SMITH: Okay. I'll be brief. Good 20 morning. My name is Brian Smith. I'm the Deputy 21 Director of the Division of Advanced Reactors and Non-22 Power Production and Utilization Facilities.
23 The staff is looking forward to the 24 discussions today with the ACRS regarding the staff's 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
13 review of Kairos' two Topical Reports on the scaling 1
methodology for their Kairos testing program and the 2
reactor coolant for the Kairos Power fluoride salt-3 cooled high temperature reactor.
4 We last presented on these reviews in 5
February, in front of most, if not all, of ACRS 6
members. Today, we'll provide a high-level overview 7
of our review and findings. At the last meeting, we 8
received some good feedback from the members and, as 9
a result, we have made a few changes to our Safety 10 Evaluations. The staff presenters will address those 11 changes in their presentation.
12 We look forward to receiving the letters 13 on the staff's review of these two Topical Reports 14 following this meeting. We also look forward to 15 future interactions with the ACRS as we complete 16 additional reviews of additional Kairos Topical 17 Reports.
18 And, with that, unless you have any 19 questions, I can turn it over to Peter Hastings for 20 some opening remarks.
21 CHAIRMAN SUNSERI: Go ahead.
22 MR. GARDNER: Good morning. This is 23 Darrell Gardner. I'm the Senior Director of Licensing 24 for Kairos Power. I do have a couple of opening 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
14 remarks, and I will be brief.
1 First of
- all, we have benefitted 2
significantly from the extensive pre-application 3
engagement that we've had with the NRC staff, and we 4
appreciate this specific invitation to describe to 5
this full Committee meeting two of our Topical Report 6
methodologies for developing and deploying the 7
fluoride salt-cooled high temperature reactor.
8 Today, we're talking specifically about 9
the Scaling Methodology Topical Report and the Reactor 10 Coolant Topical Report. I would note that these 11 reports are being discussed in an open session and we 12 have limited our discussion and presentation slides to 13 areas that we believe can be appropriately discussed 14 in this open forum. If during this presentation we 15 see questions or answers straying into proprietary 16 content, we will bring it to the Committee's 17 attention. I would request that these discussions be 18 moved to the closed session.
19 I would also note that, in many cases, 20 Kairos Power considers our business and technical 21 strategies to be business-sensitive proprietary 22 information, as well as certain technical content that 23 might represent commercially valuable intellectual 24 property.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
15 We have two primary presenters today from 1
our team to present an overview of these two reports:
2 Dr. Nicolas Zweibaum, who's the senior manager of 3
engineering testing; and Dr. Alan Kruizenga, who's the 4
director of salt chemistry. Other members of our team 5
that are present on the call today include Peter 6
Hastings, our vice president of regulatory affairs and 7
quality; Dr. Per Peterson, our chief nuclear officer; 8
Drew Peebles, our manager of safety and licensing 9
integration; and two senior licensing engineers, John 10 Price and Margaret Ellenson.
11 And that concludes my comments. Thank 12 you. We'll turn it over to Nico.
13 CHAIRMAN SUNSERI: Yes, please proceed.
14 DR. ZWEIBAUM: All right. Good morning, 15 everyone. I'd like to first confirm that everyone can 16 hear me and see my screen one more time.
17 CHAIRMAN SUNSERI: You're loud and clear.
18 DR. ZWEIBAUM: Good morning, Members of 19 the ACRS Committee and the NRC. My name is Dr.
20 Nicolas Zweibaum. I am the senior manager of 21 engineering testing at Kairos Power, and I was one of 22 the main preparers of the Scaling Methodology Topical 23 Report for which I'm going to provide an overview this 24 morning.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
16 First, Kairos Power is a mission-centered 1
company. As such, we like to start our public 2
presentations with our mission, which is to enable the 3
world's transition to clean energy with the ultimate 4
goal of dramatically improving people's quality of 5
life while protecting the environment. This mission 6
and message resonates particularly in these times when 7
everyone, or most people, are stranded at home. So, 8
I hope everyone is staying safe out there.
9 This is an outline of the main talking 10 points today, which follows the main points in the 11 Scaling Topical Report that was submitted to NRC staff 12 review. I will start by outlining the purpose of that 13 Scaling Methodology Topical Report. I'll have a brief 14 slide on the use of the hierarchical two-tiered 15 scaling, or H2TS, methodology.
16 I will then go on and explain how we are 17 using surrogate fluids in scaled experiments, thermal 18 fluids experiments. Then I will talk about the 19 application of the scaling methodology to integral 20 effects tests as well as separate effects tests that 21 support Kairos Power's evaluation methods validation.
22 And, finally, I'll have a few words of conclusion, 23 including what we asked the NRC to review and approve 24 in this Topical Report.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
17 Moving on, and for those of you who can't 1
see the screen but have the slides available, this 2
would be Slide 4 on the purpose of the Scaling 3
Methodology Topical Report. This methodology is used 4
to scale both integral effects tests, or IETs, and 5
separate effects tests, or SETs, supporting the 6
KP-FHR, which is the Kairos Power fluoride salt-cooled 7
high temperature reactor, evaluation model assessment 8
base.
9 Important to note, this is a salt-cooled 10 reactor. Our primary coolant is fluoride, which will 11 be described in a lot more detail in the next 12 presentation. So this scaling methodology is limited 13 to single-phase fluoride systems and related 14 phenomena.
15 The use of surrogate fluids enables direct 16 and comprehensive local measurements of the phenomenon 17 during investigation. And this is due to the higher 18 compatibility of existing high accuracy 19 instrumentation with low temperature surrogate fluids, 20 such as temperature and flow velocity, as opposed to 21 developing dedicated instrumentation for a high 22 temperature salt system.
23 And what Kairos Power asked the NRC staff 24 during their review was to approve our use of this 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
18 scaling methodology as laid out in the report with 1
surrogate fluids, also described in the report, 2
including heat transfer oils and water, for testing 3
that's included in the assessment base of the 4
evaluation models that support KP-FHR safety analysis.
5 I'll pause here, if there are any 6
questions so far.
7 (No response.)
8 DR. ZWEIBAUM: Okay. I don't hear 9
anything. I'm going to move on to the next slide, 10 Slide 5.
11 Why are scaling methods important to us?
12 They support acceleration of our validation testing 13 program, and it's key to note that validation testing 14 will be important to support the assessment base for 15 the safety case for the FHR. As such, we have already 16 developed important laboratory infrastructure.
17 The first one is our Rapid Lab, or R Lab, 18 which is located in our headquarters in Alameda, 19 California. There we have already developed Kairos 20 Power separate effects tests that are currently up and 21 running. These include fluid dynamics tests using 22 room temperature water at 40 percent geometric scale, 23 which allows us to match key non-dimensional numbers 24 relevant to flow dynamics phenomena, as well as heat 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
19 transfer tests using a heat transfer oil as a 1
surrogate fluid, which, again, at reduced geometric 2
scale and powering, allows us to match key non-3 dimensional numbers that are relevant to heat transfer 4
phenomena.
5 Important to note that those heat transfer 6
oils, we have run them around 72 degrees Celsius, and 7
this is to match a particular Prandtl number of the 8
fluid, which, compared to the Kairos Power reactor 9
operating with fluoride between 550 and 650 degrees 10 Celsius, is significantly lower.
11 In addition to those Kairos Power separate 12 effects tests, we are in the conceptual design phase 13 for our first Kairos Power integral effects test, 14 which would be, roughly, a house-height facility and 15 reduced area as well. And this will be located, also, 16 in this R Lab facility in Alameda, California, and 17 should be up and running before the end of the year.
18 These sets of experiments, all using 19 reduced scale of size, power, and temperature, 20 surrogate fluids and surrogate materials, will be used 21 to validate our KP-FHR evaluation models and will be 22 key in supporting deployment of our first 23 demonstration reactor that we're calling KP1. And 24 there's a very early schematic shown on the right of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
20 our reactor vessel.
1 Any questions on this?
2 CHAIRMAN SUNSERI: No questions. Thanks.
3 DR. ZWEIBAUM: Excellent. I'll move on to 4
Slide 6. This is more of a background slide on the 5
hierarchical two-tiered scaling methodology. This is 6
a generic scaling method that was previously developed 7
and approved by the NRC. It has been used for 8
development of
- previous, as well as
- current, 9
experimental programs for both lightwater reactors and 10 non-lightwater reactors. And, most importantly, why 11 this is mentioned here. is that this is the 12 methodology we have selected at Kairos Power for 13 scaling of our thermal fluids IETs and SETs as part of 14 the Evaluation Model Development and Assessment 15 Process, or EMDAP, that's described in Regulatory 16 Guide 1.203.
17 The illustration at the bottom is directly 18 inherited from an article by Novak Zuber describing 19 this methodology at a high level, which consists in 20 systemic decomposition, scale identification, then a 21 combination of top-down and bottom-up scaling. And 22 for those of you who read and reviewed the Scaling 23 Methodology Topical Report, this is the exact same 24 process we have been following to develop our scaling 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
21 arguments for the Kairos Power IETs and SETs.
1 If there are no comments or questions, I 2
will move on to the next slide, Slide 7, which covers 3
the use of surrogate fluids in scaled experiments.
4 So, why do we use surrogate fluids? As 5
briefly mentioned
- earlier, these allow us to 6
investigate the fluid flow and heat transfer phenomena 7
that are relevant to our design at significantly 8
smaller scale and required resources in terms of power 9
and temperature. More specifically, heat transfer 10 oil, a specific class of those, at room temperature or 11 close to room temperature, may simultaneously match 12 Reynolds, Prandtl, Grashof, and Froude numbers for 13 fluoride, matching those numbers for average operating 14 temperatures in the KP-FHR primary heat transport 15 system.
16 So, we are operating, as illustrated a 17 couple of slides back, around 72 degrees Celsius for 18 average operating conditions, which matches the 19 average properties of fluoride at 600 degrees Celsius.
20 In addition to those heat transfer tests, 21 we can also use water for flow dynamics testing, which 22 can simultaneously match Reynolds and Froude numbers 23 from fluoride systems. And this would be at room 24 temperature around 20 degrees Celsius.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
22 The use of surrogate fluids enables direct 1
and comprehensive local measurements of the phenomena 2
under investigation, and this is due to higher 3
compatibility of high accuracy instrumentation with a 4
low temperature environment. The ability to provide 5
those local measurements, and have a lot of those, 6
enables us to have extensive and high accuracy local 7
data that we can collect from those scaled Integral 8
effects tests and separate effects tests to support 9
the assessment base of our safety analysis tools.
10 Also, for the water testing, the use of 11 transparent surfaces can be used for direct visual 12 access, which obviously is not an option when you 13 start working with high temperature molten salt above 14 600 degrees Celsius.
15 Those surrogate fluids, it's important to 16 note we're not exactly breaking new ground here in 17 terms of using surrogate fluids for experimental 18 efforts in nuclear reactor development. This has been 19 done in the past for both single-and multi-phase flow 20 systems in support lightwater reactor development, 21 sodium-cooled reactor development,
- and, also, 22 actually, salt-cooled reactor development. This is 23 inherited from a long series of historical experiments 24 using similar surrogate fluids in early stage 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
23 development of FHR technology.
1 MEMBER PETTI: I have a question. I think 2
you touched on it in the Subcommittee, but I wanted to 3
hit again and remind folks that there is other 4
testing. You know, this has limits, this approach, 5
and I think you've outlined them. But you can't deal 6
with pebble contact friction as a result of that 7
potential particulate generation or looking at some 8
salt behavior, that you need to be at the actual 9
temperature of the actual material to understand. Is 10 that true?
11 DR. ZWEIBAUM: Absolutely. So, I think 12 the key here, which is laid out in the Topical Report 13 as well, is that any of those experiments -- and this 14 is the case where any scaled experiment -- will have 15 a number of distortions that have to be identified and 16 clearly laid out. In particular, when we run tests 17 that rely on the scaling methodology, that's laid in 18 the Topical Report. This will be accompanied by a 19 report that specifically lists the distortions and the 20 phenomena that they arise from.
21 So, the two examples you provided are 22 perfect examples of that. The key here is that we're 23 matching very closely a lot of the relevant phenomena, 24 but there will be a number of small distortions that 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
24 we will have to address and clearly look at.
1 MEMBER PETTI: Yeah, I think, you know, 2
just as a comment from one member, it would be useful 3
to have sort of a graphic that shows the whole 4
landscape of the technology development, and a little 5
box that says, okay, we're starting here, this is what 6
we're working on, I think to give people a better 7
understanding of the full set of things you plan to do 8
versus what you're talking about today.
9 DR. ZWEIBAUM: Mm-hmm.
10 MEMBER PETTI: Thanks.
11 MR. MOORE: This is Scott Moore. For all 12 the members, we do plan to have an overview 13 presentation by Kairos, but we felt that this first 14 virtual meeting probably wasn't the optimal point for 15 them to give it to us. So, we will schedule that.
16 Thank you.
17 CHAIRMAN SUNSERI: This is Matt. There 18 are several open mics, I can tell from my screen here.
19 So I'm going to ask everybody right now to look at 20 your microphone setting. Mute your microphone if 21 you're not one of the speakers or asking a question.
22 Thank you.
23 DR. ZWEIBAUM: Speaking of questions, do 24 we have any others on this specific content?
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
25 If not, I will move on to the next slide.
1 This is Slide 8 for those of you who are not following 2
on the screen.
3 So, this is a very high-level summary of 4
how we intend to apply the scaling methodology that's 5
laid out in the Topical Report to our integral effects 6
test. So, the scaling analysis that's performed in 7
the report is for a surrogate fluid -- specifically, 8
a heat transfer oil -- integral effects test that 9
replicates phenomena in the KP-FHR primary heat 10 transport system.
11 The illustration on the right is a much 12 simplified schematic that gives you a very rough sense 13 of the pumping duration of the Kairos Power fluoride 14 salt-cooled high temperature reactor. This is a 15 pebble-bed reactor. So you see the reactor core on 16 the left. We actually have two primary salt pumps in 17 our baseline pumping configuration flowing, actively 18
- flowing, molten salt to an intermediate heat 19 exchanger, that's shown on the right, that transfers 20 heat to an intermediate heat transfer system that uses 21 a secondary nitrate salt system. And then, after 22 going through the intermediate heat exchanger, or IHX, 23 the coolant goes back to the core through cold-leg 24 piping.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
26 The scaling methodology that's played out 1
in the report covers specific classes of licensing 2
basis events, and those are steady-state, normal 3
forced circulation operations with primary salt pumps 4
active, as well as transients that involve a loss-of-5 force flow and transition to natural circulation.
6 Examples of initiating events for that would be a pump 7
trip, loss of heat sink, station blackout.
8 And the methodology in the report is 9
illustrated using an idealized model of the KP-FHR 10 primary heat transport system and scaled IET.
11 However, the way the methodology is laid out in the 12 report can be extended to more representative KP-FHR 13 architectures with a number of branches and several 14 loops in parallel, in particular.
15 Are there any questions on this IET 16 portion?
17 If not, I will move on to the next slide, 18 which is Slide 9, on application of our scaling 19 methodology separate effects tests, or SETs. Those 20 SETs are used to develop closure models and 21 correlations for module-level or component-level 22 phenomena. And in the case of the Topical Report that 23 the staff reviewed, those specific tests relate to 24 fluid dynamics and heat transfer phenomena, as well as 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
27 KP-FHR design-specific phenomena. Those cover forced 1
circulation fluid dynamics; convective heat transfer; 2
conjugate heat transfer of salt structures; twisted 3
elliptical tube experiments, which is relevant to 4
design options for our intermediate heat exchanger, or 5
IHX, that couples the primary and intermediate heat 6
transport system. Pebble-bed granular flow dynamics 7
experiments. This reactor is a pebble-bed reactor.
8 So, the dynamics of the fuel moving through the core 9
are of particular interest to us. And, finally, 10 porous media or packed bed heat transfer experiments, 11 which, again, is of particular relevance to heat 12 transfer in our reactor core.
13 Any questions on this?
14 Okay. If not, I will move on to my last 15 slide, Slide 10.
16 As a summary, Kairos Power has adopted the 17 hierarchical two-tiered scaling methodology for 18 scaling of our integral effects and separate effects 19 test experiments that support KP-FHR evaluation 20 models. The Topical Report that was submitted for 21 review details the scaling methodology that we're 22 using for thermal fluids integral effects tests. That 23 models our primary heat transport system under both 24 normal operation and transients that involve 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
28 transition to natural circulation. The Topical Report 1
details the scaling methodology that's used for 2
thermal fluids separate effects tests that are 3
relevant to specific KP-FHR components and phenomena.
4 And, finally, the record describes the 5
motivations and rationales behind using specific 6
classes of surrogate fluids -- namely, heat transfer 7
oils or water -- in scaled KP-FHR IET and SET 8
experiments.
9 As a result of this, what Kairos Power 10 asked the NRC to review and approve is the specific 11 use of the scaling methodology as laid out in the 12 report with those surrogate fluids, heat transfer oil 13 and water, for testing that's included in the 14 assessment base of the evaluation model to support our 15 safety analysis.
16 And with this, if there are any questions, 17 I'd be happy to answer.
18 MEMBER PETTI: I have another question, to 19 remind myself from the Subcommittee meeting. In terms 20 of the testing, when you have heat generation and 21 you're looking at the response of the system in an IET 22 sense, are you planning to actually heat pebbles, 23 static pebbles, in the experiment or were you going to 24 pick a simpler geometry? And I was trying to remember 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
29 the rationale for the laterals decision.
1 DR. ZWEIBAUM: So, in the context of 2
integral effects tests, it is not required to use a 3
pebble bed to match the relevant non-dimensional 4
numbers at the system level. So, our options are 5
open. I will not go into the details of the design of 6
the first integral effects test facility. This is 7
still under development. But I will say it's not 8
required to use the pebble bed core in the integral 9
effects test to match the relevant heat transfer 10 properties, as well as flow dynamics properties.
11 One of the assumptions clearly stated in 12 the Topical Report is that we're focusing on 1D 13 phenomena, and, as such, in integral effects tests, we 14 are not looking at 2D or 3D flow distribution or heat 15 transfer within the core. That would be for integral 16 effects tests, if that was the question.
17 MEMBER PETTI: Yeah, I can remember this 18 discussion about the VF (phonetic) number and when it 19 was important. It required a different approach than 20 if it wasn't important in terms of the heat moving 21 into, you know, out of the pebbles.
22 DR. ZWEIBAUM: So, the VF number in the 23 application is only important for reflector 24 structures. And for that, we'll have to do some 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
30 scaling, but not for the pebble bed itself.
1 MEMBER PETTI: Okay. That's what it was.
2 Good. Thanks.
3 MEMBER MARCH-LEUBA: So, this is Jose.
4 One issue raised during the Subcommittee was the 3D 5
flow effects. If you're concerned about the integrity 6
of the structural materials due to heatup by the 7
coolant, 3D effects might give you some streaming that 8
direct coolant to a particular component. How do you 9
plan to address that?
10 DR. ZWEIBAUM: We would probably start by 11 investigating this at the separate effects test level 12 to understand if this is, indeed, a concern, before we 13 make decisions on carrying that over to the integral 14 effects test level.
15 MEMBER MARCH-LEUBA: Yeah. I suspect that 16 mostly it would be dependent on how much margin we 17 have at different temperatures. So, I mean, if you 18 have 500 degrees of margin, you don't care; if you 19 have 5 degrees of margin, then you care. So, yeah, 20 don't forget that can happen.
21 DR. ZWEIBAUM: Absolutely. But I will 22 just tell everyone that we expect to have more than 5 23 degrees
- margin, including for our structural 24 materials, which are the limiting factor in our safety 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
31 analysis.
1 MEMBER MARCH-LEUBA: Yeah, I was trying to 2
cover both ends of the 5 to 500.
3 MEMBER PETTI: So, at this point, for seed 4
conditions, will you need to test pebbles to validate 5
any of the scaling?
6 DR. ZWEIBAUM: To use pebbles -- do you 7
mean prototypical pebbles or just the pebble-bed 8
geometry in general?
9 MEMBER PETTI: Well, you can answer both.
10 The first step would be just the pebble-bed geometry, 11 and the second would, you know, be a more complex 12 test.
13 DR. ZWEIBAUM: So, in the context of 14 pebble-bed geometry, as mentioned earlier, we would 15 start with separate effects testing to see if there is 16 anything relevant to see there that has to carry over 17 to the integral effects testing. We would use 18 separate effects tests, and we have started doing that 19 actually, to measure convective heat transfer in the 20 core, and that would use the pebble-bed geometry.
21 MEMBER PETTI: Okay.
22 DR. ZWEIBAUM: Did that answer the 23 question?
24 MEMBER PETTI: Yeah, yeah.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
32 MEMBER KIRCHNER: Nicolas, this is Walt 1
Kirchner. I'd like to go back to David's observation 2
earlier. It would be useful, going forward, if we 3
were to see the intersection of -- for example, we're 4
going to hear shortly about the fluoride fluid 5
characteristics, et cetera. You've done a good job of 6
showing that, with your scaling methodology, you can 7
get to a place where you match important fluid 8
dynamics and heat transfer properties at nominal 9
operating conditions. And the purpose being, among 10 others, to benchmark your safety evaluation methods.
11 But when you get to off-normal conditions, 12 fluoride has behavioral characteristics, so to speak, 13 that are much different than heat transfer oil or 14 water. So I think it would be useful to see the 15 intersection of the fluid TR with the scaling 16 methodology and where the gaps are going forward, 17 looking at, in particular, transients, off-normal 18 conditions, where some of the characteristics of a 19 salt are much different than heat transfer oil and/or 20 water.
21 So, I'm not looking for an answer, but 22 that's a consideration, I think, going forward.
23 MEMBER PETTI: So, on chat, it says his 24 connection dropped. So he may not have heard that 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
33 question.
1 MR. HASTINGS: Yes, apologies. This is 2
Peter Hastings. His connection dropped. He's trying 3
to reestablish. But we did hear the question. So 4
we'll take it under advisement. Thank you.
5 DR. ZWEIBAUM: Hi. This is Nicolas. I 6
just came back. I'm very sorry, it dropped off at the 7
very beginning of the question. Unfortunately, I 8
didn't hear the question at all.
9 MEMBER KIRCHNER: Nicolas, this is Walt 10 again. Just an observation, not so much a question, 11 that it would be interesting going forward for us to 12 see the intersection, for example, of the fluid TR 13 with the scaling TR. And given the unique 14 characteristics of fluoride, where using heat transfer 15 oil and water might not necessarily be -- at nominal 16 operating conditions, you've done a good job of 17 showing that the scaling factors, the important things 18 like Prandtl number in salt, all the rest of those 19 parameters, are in good agreement, you don't have a 20 large divergence. But, as you get off-normal and 21 temperatures change and such, then the characteristics 22 of a salt are much different than the characteristics 23 of heat transfer oil or water.
24 DR. ZWEIBAUM: Absolutely. No, I 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
34 appreciate that. And I will say, at a high level, as 1
mentioned earlier, or at a minimum, when we do apply 2
this methodology, we'll make it clear what the 3
distortions are. That being said, to illustrate the 4
point here, I can cite, for instance, thermal 5
radiation, which obviously is something that people 6
care about when you operate at high temperature like 7
we do with the salts, as opposed to the surrogate 8
fluid. But the relative importance of thermal 9
radiation in the primary heat transport system 10 compared to convective heat transfer is pretty 11 minimal. So, this is the kind of argument that we 12 would develop in more detail when we list distortions 13 in our applications.
14 MEMBER PETTI: So, Nicolas, just on that 15 thermal radiation, I remember having a discussion with 16 Charles Forsberg from MIT about that was important, 17 that we didn't know enough about, whether it's the 18 emissivity or how thermal radiation propagates through 19 the salt. Can you shed any light on this? It was 20 surprising to me. I thought this would have been 21 something understood and it sounded like something 22 very fundamental that wasn't understood.
23 DR. ZWEIBAUM: So, we can probably bound 24 that and it would be related to the specific 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
35 properties of the salt and how it evolves in the 1
specific context of the operations of a reactor. So, 2
this is something that we would have to better 3
quantify and list as a specific distortion later. I 4
can't speak to specific numbers right now.
5 MEMBER PETTI: Yeah. Okay. So, it's more 6
of the scientific perspective than the engineering 7
perspective? There's ways to accommodate it.
8 DR. ZWEIBAUM: Yes.
9 MEMBER PETTI: Yeah. Thank you.
10 CHAIRMAN SUNSERI: Anything else on this 11 topic?
12 MEMBER PETTI: I think we're good, Matt.
13 CHAIRMAN SUNSERI: So we are going to move 14 into the next presentation, then?
15 MEMBER PETTI: Yeah, I think so.
16 DR. ZWEIBAUM: Thanks, everyone. I'm 17 going to mute myself.
18 CHAIRMAN SUNSERI: Okay. Thank you. And 19 for the Kairos folks, are you ready for the next 20 presentation?
21 VICE CHAIR REMPE: The agenda says it's 22 NRC staff now.
23 MR. MAGRUDER: Yeah. Good morning. This 24 is Stu Magruder. I'm the lead project manager for the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
36 Kairos project in the Office of Nuclear Reactor 1
Regulation. Can you hear me okay?
2 CHAIRMAN SUNSERI: I can. It wasn't clear 3
to me if these were going to be back-to-back Kairos 4
presentations followed by back-to-back staff, or what.
5 The agenda is not that clear.
6 MR. MAGRUDER: Oh, I apologize. I think 7
the intent was to have the NRC staff presentation on 8
the scaling topical, and then we'll move to the next 9
topical.
10 CHAIRMAN SUNSERI: Okay. That's fine. Go 11 ahead, then.
12 MR. MAGRUDER: Okay. So, I think I've 13 shared my screen. Can someone confirm that you can 14 see the NRC slides?
15 CHAIRMAN SUNSERI: You're there.
16 MR. MAGRUDER: Great. Great. Well, good 17 morning, everyone. The presentation this morning with 18 be brief from the staff. As Brian Smith said earlier, 19 we appreciated the feedback from the members of the 20 ACRS at the Subcommittee meeting in February. The 21 staff has made a number of changes to our Safety 22 Evaluation as a result of that discussion, and as a 23 result of further discussions with Kairos as they 24 reviewed our Draft Safety Evaluation.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
37 The primary presenter this morning will be 1
Mr. Antonio Barrett from NRR. But also on the line 2
supporting Antonio are Dr. Tim Drzewiecki and Dr.
3 Steve Bajorek. They were also kind of the primary 4
reviewers of this topical. So, I will drive the 5
presentation and Antonio will lead the discussion.
6 Antonio, take it away.
7 MR. BARRETT: Thank you, Stu. This is 8
Antonio Barrett from the Office of Nuclear Reactor 9
Regulation from the NRC staff. Can you go to the next 10 slide, please?
11 Yeah. So, for an overview of the scaling 12 methodology, the staff reviewed the Kairos Power 13 scaling methodology with respect to its application to 14 integral effects tests, separate effects tests, and 15 use of surrogate fluids. The staff developed its 16 limitations and conditions to support its conclusions 17 and findings based off that review.
18 Okay. Stu, can you go to the next slide?
19 Okay.
20 Scaling methodology is to design test 21 facilities that provide data for correlations, 22 analytical tool assessment, and demonstrate safety 23 function features of the design. For applicable 24 regulations, there's 10 CFR 50.43(e), which requires 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
38 that sufficient testing data exist on the safety 1
features of the design to assess the analytical tools 2
used for safety analyses of a sufficient range of 3
normal operating conditions, transient conditions, and 4
specified accident scenarios.
5 There's also 10 CFR 50.34, 52.47, and 6
52.79, "Contents of Applications". These require a 7
Safety Analysis Report to analyze the design and 8
performance of structures, systems, and components.
9 These analyses are typically performed with evaluation 10 models. There is guidance for the development of the 11 evaluation models in Reg Guide 1.203, using the 12 Evaluation Model Development and Assessment Process.
13 Stu, can you go to the next slide?
14 MR. MAGRUDER: Yes. And for everyone on 15 the phone, we're on Slide 4 now, "Review Scope and 16 Approach".
17 MR. BARRETT: Thank you. For the review 18 scope and approach, for integral effects tests, the 19 scaling methodology is applied to the Kairos Power 20 primary heat transport system for three scenarios, the 21 first being forced circulation, which is steady-state 22 normal operation, and then the second being a 23 transient transition from natural circulation down to 24 the third scenario, which is a quasi-steady natural 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
39 circulation.
1 The top-down scaling is based on a control 2
volume approach using 1D conservation equations. The 3
bottom-up scaling identified additional scaling routes 4
to preserve the scaling routes from the top-down 5
analysis with a focus on the individual component 6
processes.
7 The NRC staff was able to independently 8
verify the identified scaling groups from these 9
analyses. The staff finds this approach to be 10 acceptable because it's consistent with the 11 hierarchical two-tiered scaling methodology, which is 12 standard practice, and the use of non-dimensionalized 13 equations to develop similarity or scaling parameters 14 is also standard practice.
15 For separate effects tests, the applicant 16 addresses the treatment of fluid dynamics and heat 17 transfer phenomena with the use of scaling parameters 18 and values obtained from non-dimensionalized transport 19 equations. The staff finds that these scaling 20 approaches are acceptable because they are consistent 21 with standard practice for single-phase flow and heat 22 transfer.
23 For the use of surrogate fluids, they are 24 assumed throughout the entire Topical Report for the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
40 integral effects tests and separate effects tests 1
scaling. The NRC staff was able to reproduce the 2
results from a comparison of the thermal physical 3
properties applied to heat transfer oil that was 4
presented in the Topical Report. The NRC staff finds 5
that the use of surrogate fluids is acceptable because 6
the use of the fluids has a history of use in single-7 phase fluid flow and heat transfer.
8 Additionally, the analyses presented in 9
the Topical Report demonstrate that the use of 10 surrogate fluids results in experimental facilities 11 that exhibit small scaling distortions.
12 All right. Stu, can you move on to Slide 13 5?
14 MEMBER KIRCHNER: Antonio?
15 MR. BARRETT: Yes, sir?
16 MEMBER KIRCHNER: Walt Kirchner. You 17 didn't talk to the last bullet on your slide. Could 18 you just mention why that's there?
19 MR. BARRETT: Yes. So, one of the main 20 things is to limit it to the single phase. You know, 21 we don't go to freezing or anything else like that.
22 And this is part of the limitations and conditions 23 that we applied on the Scaling Topical Report. So, 24 that was the point of that bullet. It is basically 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
41 single phase. So it's not as complex as it would be, 1
and would not go to anything else other than the 2
single phase.
3 MR. MAGRUDER: Are there any other 4
questions on Slide 4 before we move on?
5 CHAIRMAN SUNSERI: Use the 5-second rule.
6 MR. MAGRUDER: Thank you.
7 MR. BARRETT: So, for changes to the SE, 8
there were only minor changes that were made to the SE 9
that don't affect any of the conclusions that were 10 made that have previously been seen. Updates were 11 made to clarify the applicant's motivation for the use 12 of surrogate fluids. And, also, there was a change to 13 the conclusion section, which updated to call out the 14 relationship to the regulations and the Evaluation 15 Model Development and Assessment Process from Reg 16 Guide 1.203. I've pasted into this the two changes 17 that were made. And there were no open items that 18 were identified from the Subcommittee meeting back in 19 February.
20 Thank you, Stu. Can you move on to the 21 next slide, Slide 6?
22 For the conclusions, the NRC staff 23 approves the Kairos Power Scaling Topical Report 24 methodology for scaling the heat transfer phenomena 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
42 for the KP-FHR primary heat transport system under 1
normal operations and transient conditions, subject to 2
the limitations and conditions.
3 The application of the scaling methodology 4
to integral effects tests and separate effects tests 5
identifies the appropriate scaling groups to capture 6
the relevant physical phenomena, subject to the 7
limitations and conditions.
8 The use of surrogate fluids, as described 9
in the scaling methodology, is capable of preserving 10 the appropriate scaling groups.
11 And that is the end of the staff's 12 presentation.
13 CHAIRMAN SUNSERI: Members, any other 14 questions or comments regarding the staff's 15 presentation?
16 MEMBER MARCH-LEUBA: This is Jose. Not 17 from me.
18 MEMBER KIRCHNER: This is Walt Kirchner.
19 Just looking at this, with regard to the limitations 20 and conditions, have you identified areas -- I'm going 21 back to 10 CFR 50.43(e). Do you feel that you have, 22 I'll use the exact terminology, "sufficient range" in 23 using these surrogate fluids to cover the transient 24 space that you may see with this particular design?
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
43 MR. BARRETT: So, there's a limitation on 1
just basically the three scenarios, to apply this just 2
to the three scenarios of the forced circulation, and 3
then down to the natural circulation and that 4
transition. So there may be transients outside of 5
that. And, if so, then this would not be applicable.
6 So, with the details that we have now, it's unknown 7
where exactly the transients will go, but this has 8
been limited to only these specific scenarios.
9 DR. DRZEWIECKI: I do want to add onto 10 that. This is Tim Drzewiecki from the staff.
11 The way it's described in the Topical 12 Report is that, if you did have a trip and you are 13 going to natural circulation, like a delta-T across 14 the core, it should be similar to what you have in 15 normal operation. And so the range of the calculated 16 distortion, which is I think 550 and 750 C, it should 17 be close to that in your transient. However, whatever 18 it is, there should be a calculated distortion and the 19 impact of that should be quantified. A limited kind 20 of method is going to reference for this Topical 21 Report.
22 Stu, can you hear me?
23 MR. MAGRUDER: Yes. Tim, I could hear 24 you.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
44 CHAIRMAN SUNSERI: Okay. Very good. All 1
right, members, any other comments or questions?
2 (No response.)
3 CHAIRMAN SUNSERI: All right. Dave Petti, 4
I'm turning it back to you.
5 MEMBER PETTI: Okay. I guess, for both 6
conditions, we have a Topical Report, then. Kairos?
7 DR. KRUIZENGA: Good morning. This is 8
Alan Kruizenga, Kairos Power. I'm the director of 9
salt chemistry. I just wanted to confirm that you can 10 both hear me and see my screen.
11 MEMBER PETTI: I can hear you. Yeah, I 12 can see it.
13 RR. KRUIZENGA: Very good. Well, good 14 morning. Great to be here. It's great to be here 15 virtually.
16 So, this Topical Report is the overview of 17 the Reactor Coolant Topical Report. I'll move on to 18 the next slide. There's a bit of a lag. It will take 19 a second, I think.
20 As was mentioned earlier, we're a mission-21 driven company. Our mission is to enable the world's 22 transition to clean energy with the ultimate goal of 23 dramatically improving people's quality of life while 24 protecting the environment.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
45 The outline for today is just to give a 1
little bit of information on the purpose of the 2
Reactor Coolant Topical Report, some of the criterion 3
that came into it from historical information, and 4
then some of the high level details behind the 5
specification for our fluoride coolant.
6 Now moving on to Slide 4. The purpose of 7
the Reactor Coolant Topical Report was really just to 8
get review and approval so that we have some basis of 9
understanding between ourselves and the NRC for the 10 design specification limits and thermal physical 11 properties for the KP-FHR as we begin to do our safety 12 analysis. So, that's the primary purpose and driver 13 behind this Topical Report.
14 VICE CHAIR REMPE: Alan?
15 DR. KRUIZENGA: Yes?
16 VICE CHAIR REMPE: Go ahead, finish. I'm 17 sorry, go ahead and finish.
18 DR. KRUIZENGA: No, that was it. I'd 19 actually ask if there's any questions.
20 VICE CHAIR REMPE: This is Joy Rempe, and 21 I do have a question. If I look at this, and the 22 remaining slides in this presentation, and even in 23 some of the staff slides, I might, as a member of the 24 public, not understand what approval of this Topical 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
46 Report means. So it would be good to have you 1
explicitly state what is meant by approval. And I 2
actually went back and looked at the staff SE when I 3
was thinking about this question last night.
4 So, could you explicitly address the topic 5
of whether you'll have to resubmit the updated version 6
of this Topical Report and if any additional testing 7
is required in order to come into the staff limitation 8
about bringing the properties listed in this report 9
into the QA program?
10 DR. KRUIZENGA: Yeah. No problem. Thank 11 you for the question. So, the purpose of the report 12 is really to establish the thermal physical 13 properties, as provided in the document.
14 VICE CHAIR REMPE: It's an initial step of 15 thermal physical properties where some of it is going 16 to have to be updated with an updated version of this 17 report. Again, look at the non-proprietary sections 18 of the SE the staff has issued, or the updated version 19 of it.
20 DR. KRUIZENGA: I understand. So, there 21 are several ways to go about qualifying the thermal 22 physical properties. Our preference is to work 23 through the qualification of the thermal physical 24 properties with methods not directly using testing, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
47 using historical information to work through that.
1 There is precedence for qualifying legacy data.
2 That's our primary desire. If needed from a safety 3
basis, safety significant standpoint, we would do 4
testing as needed. But our desire is to qualify it 5
using legacy data, primarily.
6 VICE CHAIR REMPE: And irrespective of 7
whether you are able to qualify with or without 8
testing, are you going to have to resubmit this 9
Topical Report with --
10 DR. KRUIZENGA: Could you repeat it one 11 more time?
12 VICE CHAIR REMPE: -- your qualification 13 methods?
14 DR. KRUIZENGA: I lost a little bit of 15 your question.
16 VICE CHAIR REMPE: Okay. Let me try 17 again. Are you going to have to resubmit an updated 18 version of this Topical Report demonstrating 19 summarizing the results of as you bring in the 20 qualified data to the staff?
21 So, this is kind of an initial step, is my 22 interpretation of what I read in the SE, and I think 23 I can even get that interpretation from what publicly 24 available information going to be released by the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
48 staff. Are you going to have to resubmit the Topical 1
Report?
2 MR. GARDNER: This is Darrell Gardner.
3 Let me step in here. So there's more than one way to 4
resolve the limitations and conditions. One way might 5
be to elect to provide a revision to the topical 6
report that addresses the limitations and conditions.
7 Another way would be to address those limitations and 8
conditions as part of the license application. So I 9
don't think that we're prepared to say today which way 10 we want to go. But either way, at the end of the day 11 we have to address the limitations and conditions in 12 the report.
13 VICE CHAIR REMPE: So what I think I heard 14 you say is that you may do it as part of your 15 licensing application -- which means, again, another 16 document needs to be submitted -- or you may do it 17 independently. Is that what you said, Darrell?
18 MR. GARDNER: Yes, I mean I don't think 19 that's any -- that's not really atypical of how 20 methodology topical worked in general. They represent 21 information, limitations and conditions are imposed.
22 And then when the license application uses that 23 topical, it's obligated to address the limitations and 24 conditions of the topical report.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
49 VICE CHAIR REMPE: Okay. And then I'd 1
like an overview from Kairos on your take at this 2
time, realizing that it's not completed all the work, 3
how much additional testing do you think you need in 4
order to cover the range of conditions required for 5
your -- I think earlier in the first presentation you 6
talked about a prototype?
7 MR. GARDNER: Yes, I don't think we'd be 8
prepared to have that conversation this -- one, in 9
open forum. I don't think we're prepared to have that 10 conversation today. This topical report is about the 11 properties themselves and agreement on the properties.
12 And then towards the limitations and conditions, we 13 would have to go back and make those decisions how 14 we're going to address those. I don't think we're 15 prepared today to outline our plans to close those 16 limitations and conditions.
17 VICE CHAIR REMPE: So you don't have a 18 feel yet, today, whether you've covered, for example, 19 the range of temperatures required, pressures required 20
-- whatever -- with respect to operating conditions or 21 activating conditions for your prototype even?
22 MR. GARDNER: I think I'm saying, we're 23 just not prepared to have the discussion about the 24 future testing program.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
50 VICE CHAIR REMPE: Okay, thank you.
1 DR. KRUIZENGA: So if there are no other 2
questions, I'll move on to slide 5.
3 MEMBER PETTI: Yes, go ahead Alan.
4 DR. KRUIZENGA: So one of the -- a lot of 5
the information can be referenced in this 2006 report 6
from Oak Ridge. It's an excellent compilation we 7
heavily leveraged during some of our initial screening 8
and work in this area. So there is roughly nine 9
criterion that was used for the molten salt reactor 10 experiment during the '60s and '70s -- for selecting 11 the salt. So the idea was that it had to have high 12 temperature stability, stability under radiation, 13 melting point that was below 500 degrees -- this was 14 really more due to engineering considerations. Had to 15 be compatible with containment materials, have low 16 corrosion rates.
17 Product choice is extremely important 18 because it was a liquid fueled reactor to have -- to 19 be an effective solvent for fissile material and 20 fission products. So we are not that. We are a 21 pebble reactor where the pebble is contained in the 22 fuel and the fission products. But it was fluoride 23 was chosen as an excellent solvent. And that's one of 24 the reasons, again, it was chosen. Both for its 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
51 neutronic characteristics and for its ability to act 1
as a solvent. It has negative coolant reactivity, 2
really short-term activation no long term 3
activation of the actual salt itself. It's fairly low 4
level of neutron capture and the thermal physical 5
properties are amenable to engineering and designing 6
the system.
7 MEMBER PETTI: Hey Alan?
8 DR. KRUIZENGA: Yes?
9 MEMBER PETTI: Just a question. What 10 corrosion rate -- is a little on the high side of a 11 number that I've seen, you know, for advanced 12 reactors. But it depends on the lifetime of the 13 reactor. Remind me, is this a 40-year reactor? Or a 14 60 or a 20? What?
15 DR. KRUIZENGA: Well, I think we're --
16 Darrell, though I am not sure if that's public or not 17 at this point.
18 MR. GARDNER: Oh. Copy that, I'm --
19 that's very -- we have addressed the appropriate life 20 as part of the application.
21 MEMBER PETTI: Okay.
22 DR. KRUIZENGA: Is there any other 23 questions?
24 (No response.)
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
52 DR. KRUIZENGA: Moving on to Slide 7. So 1
I haven't really said it explicitly before, but what 2
is FLiBe, FLiBe is a mixture of lithium fluoride and 3
beryllium fluoride. These are two salts. We chose it 4
for a variety of different reasons. But the FHR using 5
FLiBe is -- has an enhanced safety feature. So it has 6
a large thermal inertia, meaning that if there are 7
changes in temperature, it takes a lot of power to 8
change temperatures, so that helps to minimize rapid 9
temperature transients. The negative temperature 10 coefficient supports reactivity control and there are 11 minimal short term, long term activation products.
12 And it's really good on optimization for 13 nuclear reactor operation having high density and high 14 heat capacity and responds to thermal inertia.
15 Viscosity is comparable to water. Again, it's stable 16 under radiation at high temperatures. And then 17 lastly, I alluded to this a little bit before. But it 18 supports a safety barrier -- a safety basis as a 19 barrier to fission product release.
20 So since it's an excellent solvent, it 21 helps to capture products if they -- as they escape 22 from the TRISO protective barrier, providing extra 23 functional containment to the reactor. Are there 24 other questions on this slide?
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
53 (No response.)
1 DR. KRUIZENGA: Moving on to slide 8. So 2
this is the phase diagram. So what is being looked at 3
right here on the bottom is beryllium fluoride 4
concentration, amount of beryllium fluoride. So if 5
it's 100 percent beryllium fluoride, the melting 6
temperature is at 555 degrees -- at the top of that 7
light blue curve. It's 100-percent lithium fluoride 8
melting point is 848 degrees. Again, that's at the 9
very top of the blue curve, on the left. Where the 10 red lines are is our operating range. So we're 11 operating between temperatures of 550 to 650 degrees.
12 And in this white region along the vertical dotted 13 line -- all that means is that we're fully liquid in 14 this range. Are there other questions on this slide?
15 (No response.)
16 DR. KRUIZENGA: Moving on to slide 9. So 17 the scope of this topical report is to really just lay 18 out thermal physical properties -- density, viscosity, 19 thermal, capacity, thermal conductivity, melting 20 temperature. If this were water, we probably would 21 not be having this particular topical report. But 22 since it's a salt and it's so new to the community, 23 coolant is needed. And then you also have the 24 chemical specifications for the reactor. So we have 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
54 limits on impurities due to corrosion considerations.
1 And we also have limits on impurities for neutronic 2
considerations. Are there other questions on this 3
slide?
4 MEMBER BALLINGER: This is Ron Ballinger.
5 Are they prepared to discuss whether or not -- how 6
you're going to measure in real time the chemistry to 7
ensure that your parameters are met?
8 DR. KRUIZENGA: We are not ready to 9
discuss that feature right now. That's a good 10 question. Very good question.
11 MEMBER BALLINGER: Thank you.
12 (Pause.)
13 DR. KRUIZENGA: And that is the end of our 14 slide presentation.
15 MEMBER KIRCHNER: Alan? This is Walt 16 Kirchner. Can you go back to the slide that I will 17 call the phase diagram?
18 DR. KRUIZENGA: Yes.
19 MEMBER KIRCHNER: Please. Would you one 20 more time outline the meaning of that red box and 21 where you expect to operate?
22 DR. KRUIZENGA: So our operating region is 23 right here. Can you see my mouse on the screen, or 24 no?
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
55 MEMBER KIRCHNER: Yes.
1 (Simultaneous speaking.)
2 MR. GARDNER: -- we're not to get into 3
what's previously been proprietary. So maybe we need 4
to hold that to the closed session?
5 DR. KRUIZENGA: Well, I don't have --
6 there's no -- I am just going on the vertical line.
7 And this is -- for illustration and details are in the 8
topical report. Darrell is right. Some of those 9
details are proprietary.
10 MEMBER KIRCHNER: Now, just a moment.
11 We're looking at a phase diagram that's public 12 information.
13 DR. KRUIZENGA: That's correct.
14 MEMBER KIRCHNER: And secondly, we're 15 asking whether you're going to operate in the solid 16 and liquid zone, or a liquid zone. That's simply my 17 question.
18 DR. KRUIZENGA: We are fully in liquid 19 zone.
20 MEMBER KIRCHNER: Okay. So we should be 21 looking at -- you will be in the white space of the 22 diagram?
23 DR. KRUIZENGA: Correct.
24 MEMBER KIRCHNER: And control operating 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
56 conditions to remain comfortably above the -- I'll 1
describe as the lines there that delineate the 2
different phases.
3 DR. KRUIZENGA: That's correct.
4 MEMBER KIRCHNER: Okay, thank you.
5 DR. KRUIZENGA: No problem.
6 MEMBER BALLINGER: This is Ron Ballinger 7
again. With respect to that phase diagram, if you 8
were to have an unusual event, which caused the 9
temperature to drop -- if you're actually on that 10 line, when you get down to 458.9 -- plus or minus.2 11 degrees centigrade -- something weird is likely to 12 happen which is very dependent on the exact mole 13 fraction of beryllium fluoride. Have you folks 14 thought about what likely would happen? I mean, you 15 know, these lines are -- who knows what the range is 16 on these -- on that vertical line. But you could end 17 up with a case where you had instant conversion to 18 solid. Or in a solid-plus-liquid range where you have 19 to go through.
20 DR. KRUIZENGA: That's true. So, these 21 light blue areas are solid plus liquid?
22 MEMBER BALLINGER: Yes, that makes me feel 23 good. It's the purple area for which you're exactly 24 on the boundary.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
57 DR. KRUIZENGA: Yes.
1 MEMBER BALLINGER: And that means to me 2
that if you go to the left a little bit, you're in a 3
different regime and that is a -- if it's a puff 4
system, which it is, when you get there, things are 5
likely to get exciting.
6 MEMBER PETTI: Alan, is there any data 7
available on the kinetics of that transformation? Do 8
you know?
9 DR. KRUIZENGA: I'd have to go back and 10 look. I didn't see anything specifically in the MSRE 11 with regards to the specific kinetics. It's something 12 that we can look into, though.
13 MEMBER BALLINGER: I'm just curious as to 14 why you wouldn't want to be -- like, maybe there's a 15 reactor physics concern slightly to the right.
16 MEMBER KIRCHNER: Yes, that's where I was 17 going, Ron.
18 MEMBER BALLINGER: Because, you know, bad 19 things can happen if all of a sudden the thing locks 20 up.
21 MEMBER KIRCHNER: That's right, Ron.
22 That's where I was going. So maybe in the closed 23 session we can explore this further. But the question 24 I'll ask, you don't have to answer right now, is why 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
58 are you not at a higher mole fraction so that you have 1
much more margin in ensuring that you remain in the 2
liquid phase?
3 MR. GARDNER: So, this is Darrell Gardner 4
again. Just want to be careful of -- so I think if 5
you went back and looked at the subcommittee 6
presentation, you would see a proprietary slide that 7
does define the operating range, which is to the right 8
in the area where the asterisk is. But again, 9
cautioning everyone. We are not prepared to get into 10 that detail on the bottom axis in this open session.
11 But there is a figure that has been submitted to the 12 ACRS. It does show the specific operating ranges.
13 MEMBER BALLINGER: Thank you.
14 MEMBER BLEY: This is Dennis Bley. You 15 sense this as something we haven't seen before in 16 looking at reactors and how you will deal with this in 17 the safety analysis and are jumping the gun?
18 MR. GARDNER: So again, this is Darrell 19 Gardner. These are all great discussions that I would 20 expect us to have as we move into that discussion --
21 the transient and accident analysis. But we're a bit 22 ahead of that. This is more about the properties. So 23 we can then conduct those transients and accident 24 analysis in the future. Which would be, by the way, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
59 a subject of a -- we anticipate that being its own 1
topical report.
2 MEMBER PETTI: Are there any other 3
questions from the members?
4 MEMBER MARCH-LEUBA: This is Jose. I 5
wanted to confirm, I went to this committee slide --
6 from slide number 9. One of them, the one that's --
7 the report has the range we're talking about, and it 8
is proprietary.
9 MEMBER PETTI: Yes, I remember.
10 MEMBER MARCH-LEUBA: Yes. So if you would 11 like -- it's on Sharepoint if you can find the slides 12 from the subcommittee in February.
13 (Pause.)
14 MEMBER MARCH-LEUBA: Over and out.
15 MEMBER PETTI:
Okay.
Hearing no 16 questions, NRC staff, please?
17 MR. CHERESKIN: Good morning, this is Alex 18 Chereskin. Can everybody hear me?
19 (Pause.)
20 PARTICIPANT: Yes, we can.
21 MR. CHERESKIN: Thank you. Stu, are you 22 going to share the slides for the presentation?
23 Okay, so good morning everyone. Again, my 24 name is Alex Chereskin. I am a chemical engineer in 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
60 the Office of Nuclear Reactor Regulation. And this 1
morning I will be presenting to the ACRS full 2
committee the high level results of the staff's review 3
of the Kairos Reactor Coolant Topical Report. So next 4
slide, please.
5 So we are now on Slide 2. And this slide 6
covers a general introduction in the staff's review 7
approach for this topical report. Any submittal with 8
this topical report, Kairos had requested approval of 9
the thermal physical properties and reactor coolant 10 characteristics described in Tables 1 and 4 of the 11 topical report. And therefore, the staff only 12 provided conclusions for these portions of the topical 13 and information needed to support anything found in 14 these tables. And this is reinforced in some of the 15 staff's limitations and conditions. And I would like 16 to ask for -- if there are any questions before I move 17 on to the next slide.
18 Okay, so hearing none, this next slide 19 provides the regulatory basis for the review of this 20 topical report. And part of the regulatory basis are 21 10 CFR Sections 50.34(a) and 52.79. And these 22 regulations contain the requirements for an applicant 23 to provide information related to safety analyses and 24 also for reactor design characteristics. In addition 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
61 to these regulations in 10 CFR, in the Kairos topical 1
report there were several principal design criteria 2
that were referenced. These are described in a 3
separate topical report that was submitted by Kairos, 4
and that topical report contains a more thorough 5
discussion of the principal design criteria. And 6
there is some of them that are related to the molten 7
salt characteristics that were reviewed in this 8
topical report. And this is also discussed back at 9
the subcommittee meeting in a bit more detail. So 10 again, I would like to ask if there are any questions 11 on this slide?
12 (Pause.)
13 MR. CHERESKIN: So, hearing no questions, 14 I would like to move on to the next slide please.
15 Okay, so this slide covers the staff review of Table 16 1, which are the thermal physical properties of the 17 Kairos reactor coolant. And, sorry, I lost the visual 18 briefly. Sorry about that. So this table -- Table 1 19 contains the thermal physical properties of the Kairos 20 reactor coolant. And as Kairos had noted in its 21 report and in their presentation earlier, these are 22 derived from the Oak Ridge -- the molten salt reactor 23 experiment.
24 And so the staff reviewed the thermal 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
62 physical properties that were provided by Kairos, and 1
the overall finding was that these values were 2
reasonable for salt with the nominal composition as 3
the same as what was proposed by Kairos. And then in 4
addition to that, there were some limitations and 5
conditions in the topical report that would also need 6
to be satisfied for these properties to be found 7
acceptable. Some of this is described in section 3.2 8
of the topical report that Kairos submitted. And here 9
I just wanted to take one moment to briefly speak 10 about discussion from earlier in this meeting between 11 Member Rempe and Kairos. I believe that the 12 limitations and conditions that were being discussed 13 do provide some of the flexibility for how and when to 14 close these. And I think that the discussion earlier 15 did accurately capture the intent of the limitations 16 and conditions that were being discussed.
17 So I had just wanted to mention that. I 18 thought this would probably be an appropriate time to 19 cover that. So just to conclude here, based on the 20 nominal composition of the salt the staff did find the 21 properties in this table reasonable to use in safety 22 evaluation subject to the limitations and conditions 23 that were imposed in the -- in the staff safety 24 evaluation. So I would like to take a pause here to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
63 see if there are any comments or questions?
1 VICE CHAIR REMPE: So there were some 2
changes in your earlier SE and in the markups that 3
we've received since our subcommittee meeting. Could 4
you talk a little bit about what motivated those 5
changes? And then your thoughts about what additional 6
data -- testing might be needed versus what might be 7
addressed in the other unknown means?
8 MR. CHERESKIN: Sure, and so I just wanted 9
to note that there was a slide later in the 10 presentation that will deal with the differences. But 11 I think this is also an appropriate time to kind of 12 discuss what you had mentioned there, Member Rempe.
13 So in terms of motivation, some of the 14 reason for the change was a more clear understanding 15 of how Kairos proposes to bring some of this data into 16 its quality assurance program. And some of the 17 changes to limitations and condition also -- I believe 18 you asked for kind of my view on this -- is that there 19 are multiple ways to be able to do this. You know, 20 whether it be testing or another way. And I think 21 that some of the changes to the limitations and 22 conditions allow for that flexibility, understanding 23 that there may be more than one acceptable way to 24 perform this. And that also did result in some 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
64 changes to certain areas of the text that were 1
reflected in the staff's final SE.
2 VICE CHAIR REMPE: So, today we've heard, 3
and common sense tells us, they're going to go forward 4
with some analysis. And you've heard about scaling 5
and all of that will depend on these properties. And 6
today Kairos said, well, we may wait and submit the 7
updates to this topical report as part of our 8
application for, I guess, the prototype or whatever.
9 The demo. When does the staff really want to see an 10 updated version of this report? Showing how they're 11 going to satisfy your conditions and limitations?
12 MR. CHERESKIN: So, from my perspective, 13 I am not sure the timeline of when Kairos plans to 14 submit certain reports and when they may submit 15 certain reports that depend on this information. I 16 would think that it makes sense to have some of these 17 items resolved essentially by the time they are 18 needed. But again, I am not familiar with their exact 19 plans on when to submit the certain things. So I 20 don't know how much I could comment on that.
21 VICE CHAIR REMPE: Well, as one member, I 22 say it makes sense to try to get it resolved.
23 MR. CHERESKIN: Sure, no problem.
24 MEMBER PETTI: So I have a question in 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
65 terms of the -- bringing this under the QA program and 1
mentioning that there were more than one way to 2
resolve the open item. Are there criteria that the 3
staff uses to decide, yes, the historical data from 4
1965 was okay. Now, you know, we really need -- even 5
if it's confirmatory, we need measurements today 6
because, you know, of the number of reasons of how, 7
you know -- the pedigree was back there. You can't 8
recreate it completely. Is there something that 9
guides you in that discussion, in that assessment?
10 MR. CHERESKIN: So I think part of that 11 discussion would be held when Kairos will eventually 12 submit whatever their proposed path forward is on 13 that. However, and I do not recall the exact set of 14 criteria, but depending -- I do believe there is at 15 least some guidance, depending on the way that is 16 chosen to move forward with something like this. And 17 I believe it was done -- there was some data, I 18 believe, from one of the national laboratories on 19 separate licensing realm that used some of these 20 methods. And I think there could be some parallels 21 there.
22 MR. MAGRUDER: Yes, this is Stu Magruder 23 from the NRC staff. I agree with Alex on that. There 24 are specific requirements in the standard quality 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
66 assurance guidance and in Kairos's proposed QA topical 1
report on exactly how to do that, how to bring in 2
legacy data into their program. And as Alex 3
mentioned, we've just done that for the EPRI topical 4
report on the -- or a topical report on fuel data.
5 Actually, not the EPRI one, but the one on the 6
metallic fuel data from Idaho. So the staff is 7
learning, and I would say as we go along, on how to do 8
that. And that the process is pretty well-documented 9
in the QA process.
10 MEMBER PETTI: I just -- yes, and I was 11 wondering what the timeline is for these things -- and 12 is it, you know, if the answer is it's not acceptable 13 and the -- you need more data, the sooner you can tell 14 the applicant the better, right? So that they have 15 time to react.
16 MR. MAGRUDER: Yes, absolutely. I think 17 that's a coordinated effort among the developers and 18 the national labs, now, to make sure that whatever is 19 going to be relied on in license application has been 20 approved already.
21 MEMBER PETTI: Thank you.
22 MR. CHERESKIN: Okay, are there any 23 further questions on this slide?
24 Okay, hearing none, I would like to move 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
67 to the next slide please.
1 CHAIRMAN SUNSERI: Just for the public's 2
dialing in, could you state the slide number --
3 (Simultaneous speaking.)
4 MR. CHERESKIN: Oh, sorry about that. We 5
are on Slide 5.
6 CHAIRMAN SUNSERI: Yes, no problem. Thank 7
you.
8 MR. CHERESKIN: So, this slide covers the 9
staff review of the design specification for the KP-10 FHR reactor coolant that was provided in Table 4 of 11 the topical report. And as Kairos noted in their 12 earlier presentation, one of the considerations for 13 this table would be limits on allowable impurities.
14 And based on the information provided by Kairos, in 15 addition to the statement in Section 3.2 of the 16 topical that would determine corrosion performance of 17 materials and FliBe -- along with staff limitations 18 and conditions that are described in the staff SE, the 19 staff did find the information provided in Table 4 of 20 the topical report acceptable for use. So are there 21 any questions on this slide?
22 Hearing none, I would like to move to the 23 next slide, please. So we would be on slide 6. So 24 this slide describes changes to the SER between the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
68 draft SER, which was presented during the ACRS 1
subcommittee meeting back in February, and to the 2
final SER -- which we are discussing now. And so I 3
first wanted to mention that changes made to the SE 4
since the ACRS subcommittee meeting do not impact the 5
staff's overall conclusions. And that some of the 6
discussions that we had earlier regarding Table 1 --
7 there were some limitations and conditions that were 8
revised based on a clearer understanding of how Kairos 9
plans to do some data gathering activities. And along 10 with that, there were some corresponding changes made 11 to several sections of the text to reflect these 12 changes.
13 And there is also an opportunity to 14 combine, too, the limitations and conditions while 15 making these changes. Additionally, there was one 16 limitation and condition that was found to already be 17 covered by another. So we had the opportunity to 18 eliminate that to streamline the section a little bit 19 more. And in the text sections itself there were some 20 changes made just to provide additional clarity and 21 some editorial changes as well. Are there any 22 questions on this slide?
23 Hearing none, I would like to move to the 24 next slide, which would be Slide 7 and the final slide 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
69 in this presentation. So this slide presents the 1
staff conclusions on our topical report. And the 2
staff found that Kairos has provided reasonable 3
assurance that the information in Tables 1 and 4 of 4
the topical report satisfy regulatory requirements as 5
described in the staff SE and that this information is 6
accessible to use to begin safety analyses, and that 7
these staff approvals will be subject to limitations 8
and conditions that are specified in Section 4 of the 9
SE. Are there any further questions on my 10 presentation?
11 Okay. Hearing none, I suppose I will turn 12 it back over to Stu or the ACRS.
13 MEMBER PETTI: Thank you. Stu, do you 14 have anything else?
15 MR. MAGRUDER: No, I don't. Thank you.
16 MEMBER PETTI: Okay, members, any other 17 questions before we complete?
18 Okay, hearing none, I think this ends the 19 open session now. Chairman, back to you.
20 CHAIRMAN SUNSERI: Okay, so thank you Dave 21 and thank you Kairos and staff for both presentations.
22 So we are at a point here now where it looks like 23 we're ready to ask for any public comments regarding 24 the presentations you just heard. So, Thomas, if you 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
70 can open the public phone line and let me know when 1
that is open.
2 PARTICIPANT: Public line is open.
3 CHAIRMAN SUNSERI: Okay, thank you. So 4
any members of the public listening in on the public 5
phone line, if you care to make a comment or a 6
statement, now is the opportunity. State your name 7
and provide your comment.
And just for 8
acknowledgment, if there is anybody on the line that 9
just could say something to confirm that the line is 10 open?
11 PARTICIPANT: The line is open.
12 CHAIRMAN SUNSERI: Okay, thank you. Any 13 public comments?
14 (No response.)
15 CHAIRMAN SUNSERI: Okay, appreciate that.
16 Thomas, you can close the line now. And so next we 17 will go into report preparation, it looks like. And 18 so members, we have a crossroad here and I ask for 19 your preference on this. We can pick up with NuScale 20 report that we started yesterday, or we can go into 21 the Kairos. I think NuScale, just from a big picture 22 priority perspective, it is a higher priority and it 23 would be beneficial for us to finish those first. But 24 I am open to committing to finishing here. Anybody 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
71 want to comment?
1 MEMBER BALLINGER: This is Ron. When are 2
we -- there's a proprietary session with Kairos.
3 That's in the letter writing part?
4 CHAIRMAN SUNSERI:
That's my 5
understanding.
6 (Simultaneous speaking.)
7 MEMBER BALLINGER: So there's really no --
8 I mean, is that an appropriate venue for us to ask 9
questions to Kairos which they would consider 10 proprietary?
11 CHAIRMAN SUNSERI: Let me ask Dave for 12 guidance on that. Dave Petti?
13 MEMBER PETTI: I believe that the letter 14 and draft requires us to be in closed session. If 15 members have questions, which may be developed from 16 the reading of the letter. I think it will be much 17 along the lines of some of the questions that we heard 18 in the open session that they couldn't respond to. So 19 I think we're in a conundrum, frankly, in terms of how 20 we, you know, set out on finalities, the next step.
21 VICE CHAIRMAN REMPE: Well, could I make 22 a suggestion that I believe the letter on scaling has 23 no proprietary information and a quick read through of 24 it could be done while we're all still here without 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
72 having to connect and disconnect and all that to the 1
other line. And then perhaps it would be good to go 2
to the proprietary session and let Dave read the draft 3
letter on the coolant topicals to fully understand 4
where the concerns are. And at that point, stop and 5
go back to NuScale because it is a higher priority and 6
make sure we get through all of the letters that have 7
to be done? It's just a suggestion from one member.
8 MEMBER PETTI: I don't have a problem with 9
just doing a read through because that doesn't take 10 long.
11 MEMBER BLEY: It would seem, because we've 12 got the Kairos people here, that if we went to the 13 closed session, did a read through of that letter but 14 also let people ask proprietary questions and get that 15 out of the way for now, I am not sure you've got all 16 the right people if you wait until some arbitrary time 17 in the future.
18 (Simultaneous speaking.)
19 MEMBER BROWN: Can I make a -- this is 20 Charlie. While we were going through the other 21 presentation, all of the sudden a join a closed 22 meeting popped up and I was already in this other 23 session.
24 (Laughter.)
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
73 MEMBER BROWN: And Steve Schultz is now in 1
that session also. So I -- we got to figure out -- I 2
-- because I didn't close it because I didn't know if 3
I could get back in or not. So --
4 (Simultaneous speaking.)
5 MR. MOORE: Mr. Chairman, this is Scott 6
Moore. I think when the public line got closed, it 7
got closed all the way. In fact, it needed to be 8
muted but not closed. So, Thomas, could you bring the 9
public line back on and just mute it, please?
10 PARTICIPANT: Copy that.
11 MEMBER PETTI: So, Matt, I think Joy's 12 idea is a good one. So I only want to say, we'll 13 start with a read through of the scaling topical. And 14 since Jose led that, he can do the read through.
15 MEMBER BROWN: Is that the one that has to 16 be closed?
17 MEMBER PETTI: No. That's the one that's 18 open.
19 MEMBER BLEY: Matt?
20 CHAIRMAN SUNSERI: Yes.
21 MEMBER BLEY: I think we're off the record 22 for the meeting, are we not?
23 CHAIRMAN SUNSERI: You mean as far as the 24 transcriber goes?
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
74 MEMBER BLEY: Exactly.
1 CHAIRMAN SUNSERI: I believe that is true.
2 (Simultaneous speaking.)
3 COURT REPORTER: Can anyone hear me?
4 MEMBER BLEY: Is P&P on the record?
5 CHAIRMAN SUNSERI:
No, it's not 6
transcribed. It's public, but it's not transcribed.
7 So we can -- yes, Scott, so we're going to -- we can 8
release the transcriber -- he doesn't have to do 9
report preparation.
10 MR. MOORE: I believe that's correct.
11 (Simultaneous speaking.)
12 MR. MOORE: I think all the rest of the 13 sessions are letter writing or are P&P and none of 14 those are transcribed. Alicia, are you here?
15 PARTICIPANT: Yes, I am here.
16 MR. MOORE: And is my analysis correct 17 that everything is either letter writing or P&P and 18 none of those are transcribed?
19 PARTICIPANT: Correct.
20 (Simultaneous speaking.)
21 PARTICIPANT: Scott, this is Chris, just 22 wanted to chime in that I see here some of the 23 questions for Kairos that might have to be addressed 24 in the closed session. If that were the case, then I 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
75 would recommend that you keep the court reporter for 1
that Q&A session before we release the court reporter 2
when we switch into the letter writing session.
3 MR. MOORE: And split it up into Q&A and 4
then letter writing?
5 PARTICIPANT: Correct. Assuming that the 6
members would like to have Q&A portion being captured 7
on record.
8 MR. MOORE: That's a good point --
9 VICE CHAIR REMPE: I think some of the 10 questions are going to be about what is proprietary 11 and not proprietary in the draft coolant letter?
12 MR. MOORE: Well, Member Rempe, that's 13 fine. The transcriber can have a proprietary portion 14 of the transcription. We checked all that before 15 this.
16 MEMBER BROWN: Well, why doesn't it make 17 sense to do that proprietary session now? Read the 18 proprietary letter, ask the questions, and then we can 19 close that out?
20 MEMBER PETTI: Yes, in light of the fact 21 that the transcriber has to be here, with that 22 information, I kind of agree with you, Charlie, we 23 probably should flip it around.
24 VICE CHAIR REMPE: Do we really need a 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
76 transcriber for questions about what's proprietary and 1
not proprietary in a draft letter?
2 CHAIRMAN SUNSERI: Well, there were other 3
questions regarding the operating envelope and stuff 4
like that that I think might come up, too, so it's not 5
just administrative stuff.
6 MEMBER BROWN: I mean, we've got the open 7
-- we've got the closed session. It's there. It's 8
already opened. I know I'm in it, and Steve Schultz 9
is in it and there's somebody else in it. So I don't 10 know how it opened, but I've got it.
11 CHAIRMAN SUNSERI: Okay, so I've asked for 12 everybody's input. Thank you for all that. The 13 direction that we're going to move into is we're going 14 to break off of this open session. We're going to go 15 into closed session. And the order will be we'll have 16 a closed session, proprietary Kairos discussion 17 follow-up, and then we'll release the court reporter.
18 And then we'll go into the proprietary report 19 preparation. Dave can do the read-through. We can 20 get the major comments and then we can close that 21 session and come back into the public without the 22 court reporter after that. So --
23 VICE CHAIR REMPE: Do we need to tell the 24 public when we'll be back? Or do we just -- or expect 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
77 to hold on?
1 MR. MOORE: So, Member Rempe and Chairman 2
Sunseri, my understanding from Larry, who is on the 3
public line is that right now, he's the only member on 4
the public line. Larry, is that correct?
5 MR. BURKHART: Yes, that's correct.
6 CHAIRMAN SUNSERI: Well, I mean, that's 7
fine. But it's not all that material. We maintain a 8
public line no matter who is on it or not. And 9
according to our agenda, which was published on the 10 Federal Register, I don't think we need to make any 11 further announcements. It's clear that we're going to 12 be in and out of proprietary sessions. They can call 13 in as long as we keep the line open at the right time, 14 then we're covered. Okay, so at this point in time, 15 we are going off the public record.
16 MEMBER BLEY: Sorry, this is Dennis. Do 17 we have any problem -- I am going to shut this session 18 down and go to the other one. If some members leave 19 it open, is there cross-talk from one to the other?
20 Because we have trouble with proprietary unless we all 21 shut this other one down?
22 CHAIRMAN SUNSERI: Yes, I think the only 23 way to avoid these duplicate sessions is we're just --
24 everyone is going to have to sign out of this current 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
78 session, sign in to the new one. And then when we're 1
ready to go forward with, you know, a more open 2
session then we will close out of the private one, the 3
proprietary one, and then sign back in to this one.
4 MEMBER MARCH-LEUBA: I might have missed 5
it. What time do we join the proprietary? Do we have 6
a break?
7 CHAIRMAN SUNSERI: Yes, we're going to 8
take a 15-minute break here. We will resume at 10:30 9
10 MEMBER KIRCHNER: Matt?
11 CHAIRMAN SUNSERI: I'm sorry, go ahead.
12 MEMBER KIRCHNER: Could we take a little 13 bit longer break this time?
14 CHAIRMAN SUNSERI: Longer than 15 minutes?
15 MEMBER KIRCHNER: Yes.
16 CHAIRMAN SUNSERI: How long do you 17 suggest, Walt?
18 MEMBER KIRCHNER: So, quarter of the hour?
19 CHAIRMAN SUNSERI: Thirty-minute break?
20 Okay. We'll take a 30-minute break. We'll resume at 21 a quarter till the hour.
22 MEMBER MARCH-LEUBA: And I think we should 23 all be planning to work late. I don't know about you 24 all guys, but I don't have anything better to do. I 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
79 am here -- I have been at home and I am not going 1
anywhere. So --
2 MEMBER BLEY: Speak for yourself.
3 MEMBER MARCH-LEUBA: Okay.
4 CHAIRMAN SUNSERI: Jose, we'll see what --
5 we'll work as, you know, whatever is prudent and 6
practical. I mean, I don't want to spend our time 7
here after all the hours yesterday, I physically can't 8
do anything anyway, it was exhausting. But we'll see 9
how it goes.
10 MR. WIDMAYER: Hey, Matt?
11 CHAIRMAN SUNSERI: Yes.
12 MR. WIDMAYER: This is Derek. There's a 13 question on the IM from NuScale people that joined the 14 Skype session and would like to understand what they 15 should do.
16 MR. MOORE: Weidong, this is Scott. Does 17 NuScale have the bridge line?
18 MR. SNODDERLY: This is Mike Snodderly.
19 Let me speak. So I just was communicating with Mark 20 Chitty of NuScale. That should not be a problem.
21 This Skype session, they don't have access to the 22 Kairos Skype session. They could stay here until we 23 come back to here to do letter writing. I think it 24 would benefit NuScale if we could give them some idea 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
80 when that might occur so that they could go off and do 1
other things. But there's not a problem with -- I 2
don't see a problem to have a separate Skype session 3
for closed. I don't believe there's a problem.
4 MR. WONG: Yes, let's go to Skype for 5
closed session. It was sent out this morning -- it's 6
all to the members in this email.
7 MR. SNODDERLY: Yes, please do not share 8
that or put that on the instant message. Just go to 9
that NRC email to get it --
10 MR. WONG: I sent it out to email, yes.
11 MR. MOORE: Thank you, I misunderstood the 12 question. So for anybody on this we would --
13 (Simultaneous speaking.)
14 MR. MOORE: -- we will definitely be back 15 at 1:00. We may be back before 12:00.
16 MEMBER BROWN: Now, to be clear, we're 17 supposed to hang up from this session and we'll just 18 log back in later?
19 MR. MOORE: We'll log back in at 10:45.
20 MEMBER BROWN: Yes, we're going to do the 21 closed meeting at 10:45.
22 MR. MOORE: That's correct.
23 MR. NGUYEN: I think what Charles is 24 asking is that -- if you are an ACRS member, you 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
81 should hang up on this call and so --
1 MEMBER BROWN: Exactly.
2 MR. NGUYEN: -- go to a closed Kairos 3
session at 10:45.
4 CHAIRMAN SUNSERI: That is correct.
5 MEMBER BROWN: Right, that's what I wanted 6
to confirm. Thank you.
7 CHAIRMAN SUNSERI: And as far as the 8
NuScale folks, I don't see any way we're going to get 9
to them before 1:00 Eastern Time. So --
10 MR. SNODDERLY: Thank you very much, 11 Chairman Sunseri. I will let NuScale know and we'll 12 look forward to starting letter writing with you guys 13 at 1:00.
14 CHAIRMAN SUNSERI: Okay. So just to 15 summarize, ACRS members are going to hang up from this 16 current session. We are going to sign into the 17 proprietary session that Weidong has sent out the note 18 to our NRC email at a quarter till the hour. So that 19 would be 10:45. We will have the court reporter 20 transcribing for that part of the meeting, and then we 21 will release the transcriber and go into a proprietary 22 report writing or preparation. And then, when Dave 23 Petti is satisfied we are sufficiently progressed 24 through that, we will sign out of the proprietary 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
82 session. And I am not going to say what's going to 1
happen after that. We will decide when we get to that 2
point in the proprietary session. All right?
3 Everybody clear?
4 MR. MOORE: Yes.
5 CHAIRMAN SUNSERI: Thank you all for a 6
good open session. And we are recessed out of this.
7 See you on the proprietary line.
8 (Whereupon, the above-entitled matter went 9
off the record at 10:21 a.m.)
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
KP-NRC-2004-001 707 W Tower Ave Kairos Power LLC 121 W Trade St, Ste 1010 Alameda, CA 94501 www.kairospower.com Charlotte, NC 28202 April 1, 2020 Project No. 99902069 US Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001
Subject:
Kairos Power LLC Presentation Materials for Kairos Power Briefing to the Advisory Committee on Reactor Safeguards on Reactor Coolant and Scaling Methodology Topical Reports This letter transmits presentation materials for the April 9, 2020, briefing for the Advisory Committee for Reactor Safeguards (ACRS) full committee meeting. At the meeting, participants will discuss two topical reports that were submitted to the Nuclear Regulatory Commission staff for review and approval:
(1) Reactor Coolant for the Kairos Power Fluoride Salt-Cooled High Temperature Reactor (KP-TR-005-P);
and (2) Scaling Methodology for the Kairos Power Testing Program (KP-TR-006-P).
provides the non-proprietary presentation materials for the open session.
If you have any questions or need any additional information, please contact Drew Peebles at peebles@kairospower.com or (704) 275-5388 or Darrell Gardner at gardner@kairospower.com or (704) 769-1226.
Sincerely, Peter Hastings, PE Vice President, Regulatory Affairs and Quality
Enclosures:
- 1) Open Session Presentation Materials for the April 9, 2020, ACRS Briefing (Non-Proprietary) xc (w/enclosure):
Benjamin Beasley, Chief, Advanced Reactor and Licensing Branch Stewart Magruder, Project Manager, Advanced Reactor and Licensing Branch Weidong Wang, Senior Staff Engineer, Advisory Committee for Reactor Safeguards
Open Session Presentation Materials for the April 9, 2020, ACRS Briefing (Non-Proprietary)
Copyright © 2020 Kairos Power LLC. All Rights Reserved.
No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.
OVERVIEW OF SCALING METHODOLOGY TOPICAL REPORT ACRS FULL COMMITTEE MEETING, APRIL 8, 2020
Confidential and Proprietary No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC Kairos Powers mission is to enable the worlds transition to clean energy, with the ultimate goal of dramatically improving peoples quality of life while protecting the environment.
Copyright © 2020 Kairos Power LLC. All Rights Reserved.
No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC 3
Outline
- Purpose of the Scaling Methodology Topical Report
- Hierarchical Two-Tiered Scaling (H2TS) Methodology
- Use of Surrogate Fluids in Scaled Experiments
- Application of Scaling Methodology to Integral Effects Tests (IETs)
- Application of Scaling Methodology to Separate Effects Tests (SETs)
- Conclusions
Copyright © 2020 Kairos Power LLC. All Rights Reserved.
No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.
4 Purpose of the Scaling Methodology Topical Report
- The methodology is used to scale integral effects tests (IETs) and separate effects tests (SETs) supporting the KP-FHR evaluation model assessment base
- The methodology is limited to single-phase Flibe systems and phenomena
- Surrogate fluids enable direct and comprehensive, local measurements of the phenomena under investigation due to higher compatibility of high-accuracy instrumentation (e.g., temperature and flow velocity)
- Kairos Power is requesting NRC review and approval to:
Use the scaling methodology with surrogate fluids described in the report (heat transfer oil and water) for testing included in the assessment base of evaluation models supporting KP-FHR safety analysis 4
Copyright © 2020 Kairos Power LLC. All Rights Reserved.
No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.
5 Scaling Methods Support Acceleration of Kairos Powers Validation Testing Roadmap KP-1 Demonstration Reactor Validation of KP-FHR Evaluation Models Full scale Flibe coolant (550-650°C)
TRISO fuel pebbles Reduced scale (size, power, temperature)
Surrogate fluids Surrogate materials KP-IETs R-Lab 2020 1/2 Height KP-SETs R-Lab 2020 Fluid dynamics tests Room-temperature water 40% geometric scale Heat transfer tests Heat transfer oil (72°C)
Reduced geometric scale
Copyright © 2020 Kairos Power LLC. All Rights Reserved.
No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.
6 Hierarchical Two-Tiered Scaling (H2TS) Methodology
- Generic scaling method previously developed for and approved by the NRC
- Used for development of previous and current experimental programs for LWRs and non-LWRs
- Selected by Kairos Power for scaling of thermal fluids IETs and SETs as part of the Evaluation Model Development and Assessment Process described in Regulatory Guide 1.203 Source: Zuber, N. et al. (1998).
An Integrated Structure and Scaling Methodology for Severe Accident Technical Issue Resolution: Development of Methodology. Nuclear Engineering and Design, 186 (1), 1-21.
Copyright © 2020 Kairos Power LLC. All Rights Reserved.
No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.
7 Use of Surrogate Fluids in Scaled Experiments
- Surrogate fluids allow the investigation of fluid flow and heat transfer phenomena relevant to the KP-FHR design at significantly smaller scale and required resources (e.g., power and temperature)
Heat transfer oil at room temperature may simultaneously match Reynolds, Prandtl, Grashof and Froude numbers for Flibe at average operating temperatures in the KP-FHR primary heat transport system Water may be used for simultaneous matching of Reynolds and Froude numbers
- Surrogate fluids enable direct and comprehensive, local measurements of the phenomena under investigation due to higher compatibility of high-accuracy instrumentation (e.g.,
temperature and flow velocity) with low-temperature environment
- As a result, extensive, high-accuracy local data may be collected from scaled IETs and SETs to support the assessment base of KP-FHR safety analysis evaluation models, and transparent surfaces may be used for direct visual access
- Surrogate fluids have been used extensively in past and current experimental efforts for nuclear reactor development in both single-and multi-phase flow systems
Copyright © 2020 Kairos Power LLC. All Rights Reserved.
No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.
8 Application of Scaling Methodology to IETs
- Scaling analysis for a surrogate fluid (heat transfer oil) IET of the KP-FHR primary heat transport system
- Classes of licensing basis events illustrated in the topical report:
Steady-state, normal forced-circulation operations Transients involving loss of forced flow and transition to natural circulation (e.g., pump trip, loss of heat sink)
- Illustrated using an idealized model of the KP-FHR primary heat transport system and scaled IET 8
Copyright © 2020 Kairos Power LLC. All Rights Reserved.
No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.
9 Application of Scaling Methodology to SETs
- SETs are used to develop closure models and correlations for module/component-level phenomena
- Topical report covers generic fluid dynamics and heat transfer phenomena, and KP-FHR design specific phenomena:
Forced circulation fluid dynamics Convective heat transfer Conjugate heat transfer with solid structures Twisted elliptical tube experiments Pebble bed granular flow dynamics experiments Porous media and packed bed heat transfer experiments 9
Copyright © 2020 Kairos Power LLC. All Rights Reserved.
No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.
10 Conclusions
- Kairos Power has adopted the H2TS methodology for scaling of IET and SET experiments in support of KP-FHR evaluation models
- The report details the scaling methodology used for thermal fluid IETs that will model the KP-FHR primary heat transport system under normal operations and transients that involve transition to natural circulation
- The report details the scaling methodology used for thermal fluid SETs relevant to specific KP-FHR components and phenomena
- The report describes the motivations and rationales for using specific classes of surrogate fluids in scaled KP-FHR IET and SET experiments
- Kairos Power is requesting NRC review and approval to:
Use the scaling methodology with surrogate fluids (heat transfer oil and water) described in the report for testing included in the assessment base of evaluation models supporting KP-FHR safety analysis
Confidential and Proprietary No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC
, Part 810 Export-Controlled Information 11 Questions
Copyright © 2020 Kairos Power LLC. All Rights Reserved.
No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.
OVERVIEW OF REACTOR COOLANT TOPICAL REPORT ACRS FULL COMMITTEE MEETING, APRIL 8, 2020
Confidential and Proprietary No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC Kairos Powers mission is to enable the worlds transition to clean energy, with the ultimate goal of dramatically improving peoples quality of life while protecting the environment.
Copyright © 2020 Kairos Power LLC. All Rights Reserved.
No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.
3 Outline
- Purpose of Reactor Coolant Topical Report
- Coolant Selection Criterion for MSRE
- KP-FHR Flibe Specification Corrosion allowances Neutronic Considerations 3
Copyright © 2020 Kairos Power LLC. All Rights Reserved.
No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.
4 Purpose of the Reactor Coolant Topical Report Kairos Power requested the NRC review and approval of the reactor coolant design specification limits and thermophysical properties for the Kairos Power Fluoride Salt-Cooled, High Temperature Reactor (KP-FHR).
Copyright © 2020 Kairos Power LLC. All Rights Reserved.
No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.
5 Compilation of Coolant Data and Information Reference leveraged heavily for basis of Flibe due to excellent compilation of broad information.
Williams ORNL-2006
Copyright © 2020 Kairos Power LLC. All Rights Reserved.
No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.
6 Coolant Selection Criterion for MSRE Criteria Flibe Information
- 1. Stability at high temperatures (>800°C)
Vapor pressure is low over operational temperatures
- 2. Stability under radiation Minimal degradation if using 7Li
- 3. Melting point below 500°C The melting point of Flibe is 459°C
- 4. Materials compatible Clean Flibe has low corrosion rates. Additions of elemental beryllium control corrosion to less than 30 micron/year
- 5. Effective solvent for fissile material and fission products Flibe was solvent for MSRE fuel salt; able to dissolve fuel and most fission products
- 6. Negative coolant reactivity Coolant density Coefficient: -$0.01 per 100°C Coolant Void Ratio: -$0.11*
- 7. Low short-term activation and no long-life activation Short-term activation is small.
- 8. Low relative neutron capture 8x neutron capture relative to graphite.
- 9. Thermophysical properties
- Analysis performed using prismatic VHTR geometry.
From Williams ORNL-2006
Copyright © 2020 Kairos Power LLC. All Rights Reserved.
No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.
7 KP-FHR uses Flibe (2LiF:BeF2) as a coolant
- Flibe coolant provides enhanced safety features relative to LWR designs.
Large thermal inertia minimizes rapid temperature transients Negative temperature coefficient of reactivity supports reactivity control Minimal short-term and long-term activation
- Flibe is an optimization for nuclear reactor operation High density and heat capacity (i.e. thermal inertia)
Viscosity comparable to water Stable under radiation and at high temperatures
- Flibe supports safety basis as a barrier to fission product release.
Absorbs fission products that escape the TRISO protective layer, providing additional functional containment protection.
LiF-BeF2 mixture (Flibe)
Copyright © 2020 Kairos Power LLC. All Rights Reserved.
No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.
8 Lithium Fluoride, Beryllium Fluoride Phase Diagram Grimes, W.R., Bohlmann, E.G., Meyer, A.S., and Dale, J.M.,Fuel and Coolant Chemistry, Chapter 5 in Rosenthal, M.W., Haubenreich, P.N., and Briggs, R.B., The Development Status of Molten-Salt Breeder Reactors, Oak Ridge National Laboratory Report ORNL-4812 (1972).
- KP-FHR operating range Simplified from ORNL-DWG71-527OR2 BeF2
(mole fraction)
Temperature (oC) 363.5 +/- 0.5oC 458.9 +/- 0.2oC 848 555 solid solid & liquid liquid
Copyright © 2020 Kairos Power LLC. All Rights Reserved.
No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.
9 Reactor Coolant Topical Report Scope Reactor Coolant Topical Report Defines
- Thermophysical properties of Flibe Density, viscosity, heat capacity, thermal conductivity, melting temperature, etc.
- Chemical Specification used in KP-FHR Corrosion allowances; impurities known to cause corrosion have limits on concentration Neutronics considerations; impurities important for neutronics have limits on concentration
Confidential and Proprietary No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC
, Part 810 Export-Controlled Information 10 Questions
Presentation to the ACRS Full Committee Staff Review of Kairos Topical Reports KP-TR-006, REV 1, SCALING METHODOLOGY FOR THE KAIROS POWER TESTING PROGRAM Presenters:
Stu Magruder - Project Manager, Office of Nuclear Reactor Regulation (NRR)
Antonio Barrett, Reactor Systems Engineer, NRR April 9, 2020 (Open Session) 1
Scaling Methodology for the Kairos Power Testing Program Overview
- Review scope and approach
- Integral effects tests (IETs)
- Separate effects tests (SETs)
- Surrogate fluids
- Conclusions/Limitation and conditions 2
Regulatory Basis
- An approved scaling methodology is used to design test facilities that provide data for analytical tool assessment and demonstrate safety features of a design.
- Applicable regulations:
- 10 CFR 50.43(e) requires that sufficient test data exist on the safety features of the design to assess the analytical tools used for safety analyses over a sufficient range of normal operating conditions, transient conditions, and specified accident scenarios
- 10 CFR 50.34, 10 CFR 52.47, and 10 CFR 52.79 "Contents of Applications" require a safety analysis report to analyze the design and performance of structure, systems, and components
- Analyses are typically performed with evaluation models (i.e., analytical tools) 3
Review Scope and Approach IET Review Top-down
- Control volume approach consistent with top-down evaluation from Hierarchical Two-Tier Scaling Analysis (H2TS)
- Review transport equations and associated assumptions
- Perform independent non-dimensional analysis Bottom-up
- Compare scaling groups against results from traditional non-dimensional analyses SET Review Compare against standard practice where applicable Identify unique design features and access scaling approach experience base Surrogate Fluid Review Perform independent calculations to compare thermophysical properties Investigate sources of distortion Identify limitations to the use of surrogate fluids 4
Changes to SER Minor changes to the SER following the Subcommittee meeting Updated the applicant's motivation for the use of surrogate fluids to include fewer required resources, and to enable the use of available and accurate instrumentation.
Updated the conclusion discussion to include the regulatory basis to develop assessment data as required by EMDAP and in partial fulfillment of 10 CFR 50.43(e).
Open Items from Subcommittee meeting No follow-up questions or activity identified during Subcommittee meeting 5
Conclusions The NRC staff approves the KP-TR-006 topical report methodology for scaling momentum and heat transfer phenomena for the KP-FHR PHTS under normal operations and transient conditions, subject to 3 Limitations and 5 Conditions
- The application of the scaling methodology to IETs identifies the appropriate scaling groups to capture the relevant physical phenomena subject to the applicable Limitation and Conditions
- The application of the scaling methodology to SETs identifies the appropriate scaling groups to capture the relevant physical phenomena subject to the applicable Limitations and Conditions.
- The use of surrogate fluids as described in KP-TR-006 is capable of preserving the appropriate scaling groups, with acceptable distortions 6
Backup Slides 7
Limitations and Conditions Limitation 1: NRC staff's approval on the identified scaling groups is limited to the KP-FHR Primary Heat Transport System for 1-D flow for the 3 scenarios identified in the TR Limitation 2: Modeling of specified flow behavior requires justification outside the scope of the scaling TR Limitation 3: The use of surrogate fluids cannot be used for scenarios involving a change of phase Condition 1: An evaluation model that references the TR will include a summary of a distortion analysis that evaluates the as-built and completed test distortions.
Condition 2: An evaluation model that references the TR will assess the impact of the distortion attributed to parasitic heat loss differences between the KP-FHR prototype and the scaled facility.
Condition 3: An evaluation model that references this TR for the scaling of twisted tube heat exchangers needs to assess the potential for unidentified scaling distortions, due to uncertainties in the adequacy of the geometric scaling presented for twisted tube heat exchangers, in the evaluation model assessment and uncertainty quantification.
Condition 4: An evaluation model that references this TR for the scaling of heat transfer phenomena in packed beds, and the associated development of heat transfer correlations, needs to assess the potential for unidentified scaling distortions, due to uncertainties in the adequacy of the geometric scaling presented for porous media or packed beds, in the evaluation model assessment and uncertainty quantification.
Condition 5: Distortion report will quantify the impact of thermal radiation heat transfer 8
Presentation to the ACRS Full Committee Regarding NRC Staff Review of KP-TR-005, Revision 1 Reactor Coolant for the Kairos Power Fluoride Salt-Cooled High Temperature Reactor Topical Report, Revision 1 ACRS Full Committee Meeting April 9th, 2020 Presenters:
Alexander Chereskin Stewart Magruder April 9, 2020 Open Session April 9, 2020 1
Introduction and Review Approach
- Kairos requested approval of the thermophysical properties in Table 1 of the TR and the reactor coolant characteristics in Table 4 of the TR.
- The staff only provided conclusions for these portions of the TR and any information needed to support the values and parameters found in these tables.
- Limitation and Condition 1 states that an applicant referencing this TR may only use information provided in Tables 1 and 4 (subject to other relevant Limitations and Conditions).
2 April 9, 2020
Regulatory Basis
- Title 10 of the Code of Federal Regulations (10 CFR) Sections 50.34(a) and 52.79 contain requirements regarding reactor design characteristics and preliminary safety analyses.
3 April 9, 2020
Staff Review of Table 1 Kairos stated that the thermophysical properties are predominately derived from the Oak Ridge National Laboratories Molten Salt Reactor Experiment.
Staff reviewed the thermophysical property correlations and expected uncertainties provided in Table 1 of the Reactor Coolant Topical Report.
The staff found the thermophysical properties and associated uncertainties in Table 1 acceptable for use subject to Limitations and Conditions.
- An 'Open Item' in Section 3.2 of the TR states that Kairos will bring this data under its QA program.
4 April 9, 2020
Staff Review of Table 4 Table 4 provides the design specification for the KP-FHR reactor coolant.
The staff found the design specification acceptable subject to Limitations and Conditions.
- Additionally, Kairos stated in Section 3.2 of the TR that corrosion performance of 316H in Flibe (consistent with specified impurity limits) will be addressed.
5 April 9, 2020
- Two Limitations and Conditions were consolidated based on clearer understanding of planned Kairos data gathering activities described in Section 3.2 of the TR.
- Corresponding changes to several text sections to reflect this.
- Eliminated one redundant Limitation and Condition.
- Additional clarity and editorial changes.
6 April 9, 2020 Changes to SER
- Kairos has provided reasonable assurance that the information in Tables 1 and 4 of the Reactor Coolant TR will satisfy regulatory requirements as described in the staff SER.
- Information is acceptable to use in safety analyses.
- The Staff approvals are subject to the Limitations and Conditions in Section 4.0 of the SER.
7 April 9, 2020 Staff Conclusions