ML23248A272
| ML23248A272 | |
| Person / Time | |
|---|---|
| Issue date: | 08/23/2023 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| References | |
| NRC-2510 | |
| Download: ML23248A272 (1) | |
Text
Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION
Title:
Advisory Committee on Reactor Safegaurds TerraPower NATRIUM Design Reactor Docket Number:
(n/a)
Location:
teleconference Date:
Wednesday, August 23, 2023 Work Order No.:
NRC-2510 Pages 1-141 NEAL R. GROSS AND CO., INC.
Court Reporters and Transcribers 1716 14th Street, N.W.
Washington, D.C. 20009 (202) 234-4433
NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 www.nealrgross.com 1
1 2
3 DISCLAIMER 4
5 6
UNITED STATES NUCLEAR REGULATORY COMMISSIONS 7
ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 8
9 10 The contents of this transcript of the 11 proceeding of the United States Nuclear Regulatory 12 Commission Advisory Committee on Reactor Safeguards, 13 as reported herein, is a record of the discussions 14 recorded at the meeting.
15 16 This transcript has not been reviewed, 17 corrected, and edited, and it may contain 18 inaccuracies.
19 20 21 22 23
1 UNITED STATES OF AMERICA 1
NUCLEAR REGULATORY COMMISSION 2
+ + + + +
3 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 4
(ACRS) 5
+ + + + +
6 DESIGN CENTERED LICENSING: TERRAPOWER SUBCOMMITTEE 7
+ + + + +
8 WEDNESDAY 9
AUGUST 23, 2023 10
+ + + + +
11 The Subcommittee met via hybrid in-person 12 and Video Teleconference, at 8:30 a.m. EDT, Thomas 13 Roberts, Chairman, presiding.
14 15 COMMITTEE MEMBERS:
16 THOMAS ROBERTS, Chair 17 RONALD G. BALLINGER, Member 18 CHARLES H. BROWN, JR., Member 19 VICKI BIER, Member 20 VESNA DIMITRIJEVIC, Member 21 GREGORY HALNON, Member 22 WALT KIRCHNER, Member 23 JOSE MARCH-LEUBA, Member 24 ROBERT MARTIN, Member 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
2 DAVID PETTI, Member 1
JOY L. REMPE, Member 2
3 ACRS CONSULTANT:
4 DENNIS BLEY 5
STEVE SCHULTZ 6
7 DESIGNATED FEDERAL OFFICIAL:
8 KENT HOWARD 9
10 ALSO PRESENT:
11 REED ANZALONE, NRR 12 BRIAN JOHNSON, TerraPower 13 NICK KELLENBERGER, TerraPower 14 ED LYMAN, Public Participant 15 CANDACE DE MESSIERES, NRR 16 SCOTT MOORE, ACRS 17 GEORGE PICCARD, TerraPower 18 JESSE SEYMOUR, NRR 19 MALLECIA SUTTON, NRR 20 ERIC WILLIAMS, TerraPower 21 GEORGE WILSON, TerraPower 22 EMILY YOUNG, TerraPower 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
3 C-O-N-T-E-N-T-S 1
2 Opening Remarks and Objectives 3
By Thomas Roberts.............
4 4
TerraPower Nuclear Island and Energy Island 5
Interface TR Submittal 6
By Nick Kellenberger, Eric Williams, George 7
Wilson 7
8 NRC Staff Presentation Nuclear Island and Energy 9
Island Interface TR Review 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
4 P-R-O-C-E-E-D-I-N-G-S 1
8:30 a.m.
2 CHAIR ROBERTS: This meeting will now come 3
to order. This is a meeting of the ACRS Subcommittee 4
for the TerraPower NATRIUM Design Reactor. I'm Tom 5
Roberts, Chair of the Subcommittee.
6 ACRS members in attendance are Ron 7
Ballinger, Juan, or Jose March-Leuba, Matt Sunseri, 8
Dave Petti, Joy Rempe, Bob Martin, Vicki Bier, Greg 9
Halnon, and Charlie Brown. Members online are Walt 10 Kirchner and Vesna Dimitrijevic. Can you please 11 confirm you're online?
12 MEMBER DIMITRIJEVIC: Yes, we are here.
13 Good morning.
14 CHAIR ROBERTS: Good morning, Vesna. And 15 Walt?
16 MEMBER KIRCHNER: Yes, Tom. Good morning.
17 CHAIR ROBERTS: Yes, good morning. And 18 consultants, we have Steve Schultz in the room, and 19 Dennis Bley online. Dennis, can you confirm you're 20 there?
21 MR. BLEY: I'm here.
22 CHAIR ROBERTS: Thank you. Now, Kent 23 Howard of the ACRS staff is the designated federal 24 official for the meeting, over there.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
5 Today the Subcommittee will discuss a 1
topical report submitted by TerraPower, and reviewed 2
by the NRC staff on the subject of independence 3
between the nuclear island and the energy island of 4
the NATRIUM design.
5 The topical report sets out to make the 6
case that all structured systems and components, or 7
SSCs, relied upon for reactor safety are on the 8
nuclear island. And events on the energy island are 9
sufficiently decoupled from the nuclear reactor that 10 the energy island can be considered to be non-safety, 11 and not require use of reactor safety standards in 12 design and construction.
13 These are more detail on this from the 14 applicant, as well as the contents of the direct 15 safety evaluation from the NRC staff.
16 The ACRS was established by statute, and 17 is governed by the Federal Advisory Committee Act, or 18 FACA. The NRC implements FACA in accordance with 19 regulations found in Title 10 of the Code of Federal 20 Regulations, Part 7.
21 We hold Subcommittee meetings to gather 22 information and perform preparatory work that will 23 square deliberation at a full Committee meeting if 24 necessary.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
6 The Committee can only speak to its 1
published letter reports. As with any ACRS meeting, 2
attendees should consider any remarks by ACRS members 3
are their personal comments and not Committee 4
positions.
5 The rule for participation in all ACRS 6
meetings, including today's were announced previously 7
in the Federal Register, and included on the ACRS 8
section of the USNRC's public website.
9 This website provides our charter, by-10 laws, agendas, letter reports, and transcripts of all 11 full and Subcommittee meetings, including presented 12 material.
13 As stated on the website, members of the 14 public who desire to provide written or oral input to 15 the Subcommittee may do so, and should contact the 16 designated federal officer five days prior to the 17 meeting as practicable.
18 We did not receive any written comments or 19 requests to make oral statements from members of the 20 public regarding today's session.
21 Today's meeting is open to public 22 attendance. And there will be time set aside during 23 the meeting for comments from members of the public 24 attending or listening to our meetings.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
7 Today's meeting is a hybrid meeting, 1
meaning there is both in person attendance and remote 2
capability via a Microsoft Teams link.
3 A transcript of today's meeting is being 4
kept. Therefore, we request that meeting participants 5
identify themselves when they speak, and speak with 6
sufficient clarity and volume so they can be readily 7
heard.
8 At this time, I ask all the attendees to 9
put their devices on mute, both the Teams computers 10 and cell phones, to minimize disruptions, and unmute 11 only when speaking.
12 We'll now proceed with the meeting. And 13 I'll call upon Mr. Nick Kellenberger from TerraPower 14 to make introductory remarks.
15 MR. KELLENBERGER: Good morning and thank 16 you, ACRS Subcommittee. We are excited for our first 17 Subcommittee meeting. We had a presentation earlier 18 this year on the overview of our plant, but this will 19 be the first, this is the first meeting on our, one of 20 our topical reports.
21 As the Chair said, I'm Nick Kellenberger.
22 I'm a licensing manager at Terra Power, and joined by, 23 to my left Eric Williams. He's the Senior Vice 24 President and design authority for the NATRIUM 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
8 reactor; George Wilson, who's our Vice President of 1
Reg Affairs and Licensing.
2 Also in the room, Emily Young, our manager 3
of deterministic safety analysis, and George Piccard, 4
who's our Site Director for Unit 1, first NATRIUM 5
plant. With that I'm going to turn it over to Eric to 6
walk us through the beginning. And then George will 7
take over near the end.
8 MEMBER MARCH-LEUBA: Sorry. These 9
microphones are very, very directional. All of the 10 people in the --
11 MR. WILLIAMS: Okay. I'm going to go 12 ahead and talk. If there's any problems with the 13 audio, just stop me and let me know. So, my name is 14 Eric Williams. Thank you for the introduction. And 15 I'm happy to be here to talk about this topical report 16 today.
17 We've lined up a presentation that goes 18 through the topics here. We're going to go back and 19 look at the reactor overview of the design. But since 20 we were here recently and explained the reactor 21 overview recently to the ACRS I'm going to more focus 22 on what's important for the topical report discussion 23 today. So, going through and pointing out the key 24 features of the energy island and nuclear island 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
9 interfaces, and things like that.
1 Then we're going to talk about operation 2
flexibility, and how the energy island is designed to 3
operate and take care of transients. We're going to 4
talk about what we mean by transient separation, so 5
that will get into some of the structure that we're 6
using to look at licensing basis events, and all of 7
the licensing modernization project approach.
8 And then we're going to end with 9
regulatory impacts. And George is going to take that 10 portion at the end. And so, really all of the 11 discussion is really designed to set up that 12 discussion on regulatory impact. So, we'll jump right 13 in.
14 All right. So here's the look that we 15 usually portray if we're talking about the NATRIUM 16 safety features. Some of the main differences to 17 other technologies are kind of tabulated there on the 18 left.
19 It is a pool type metal field sodium fast 20 reactor. A lot of the experience in the United States 21 has been with loop reactors. There's been a lot of 22 international experience on pool reactors.
23 So, that's one of the key aspects here 24 that's important to talking about the thermal inertia 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
10 that exists in the primary heat transport system.
1 Having the pool reactor in the large volume coolant in 2
the vessel is an important feature for that.
3 Metal fuel, and the specific design for 4
the NATRIUM reactor lead to a lot of the safety 5
features that we portray on this slide. The fact that 6
it's metal fuel, and it's metal coolant makes the two 7
very compatible with one another, which adds another 8
aspect to the safety case.
9 And the molten salt energy island is 10 another change that we've introduced into the design, 11 that we think adds a lot to the safety case. And 12 we're going to be talking a lot about that part today.
13 Other sodium fast reactors have had steam 14 gener -- had sodium steam generators, sodium water 15 steam generators. So that is one of the aspects that 16 we've eliminated by design. Because the sodium water 17 reaction is highly energetic.
18 What we now have are sodium salt heat 19 exchangers. So, we'll be introducing a lot about 20 those today in the discussion. And there is also an 21 exothermic reaction between sodium and salt that we've 22 mentioned before, much more benign reaction than 23 sodium and water. But still something that is 24 addressed in the design.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
11 And the large thermal inertia is something 1
that's going to come up a lot, not just in the primary 2
heat transport system, but the intermediate heat 3
transport system, and the salt system as well.
4 There's a lot of volume of coolant in those systems 5
that can absorb heat. So, those are kind of the key 6
aspects for setting up today's discussion. We've got 7
a --
8 MR. BLEY: Eric?
9 MR. WILLIAMS: -- fundamental safety --
10 Oh, yes.
11 MR. BLEY: This is Dennis Bley online. I 12 don't know that we talked about it last time. But 13 looking at this picture there's a lot of stuff inside 14 your pool. Can you say anything, just briefly, about 15 how you've set this up to be able to do maintenance 16 with such a compact design?
17 MR. WILLIAMS: Yes, sure. So, all of the 18 main components are designed to be removed and 19 replaced, or go through operation and maintenance.
20 So, even the kidney shaped intermediate heat 21 exchangers are designed to come out. The mechanical 22 primary sodium pumps can be removed.
23 There's a maintenance port as well in the 24 reactor vessel head that I don't think can be seen on 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
12 the diagram, that can be used to go in and hook up 1
different machines to perform maintenance.
2 And then of course you've got the 3
refueling equipment that mates up with the reactor 4
vessel head to maintain the fuel assemblies. So, we 5
are designing that for maintenance.
6 I think the picture gives the impression 7
of more congestion than there actually is. Certainly 8
in the center of the reactor vessel head, where the 9
control rods come in. That is a highly congested part 10 right there just due to the control rods, the 11 refueling. That's the rotating plug that handles the 12 refueling equipment as well.
13 So there's some congestion in that area.
14 But it's still a very large vessel. And we have the 15 equipment, you know. I think it looks a lot more 16 congested on the picture than it actually is. But --
17 MR. BLEY: Okay.
18 MR. WILLIAMS: -- the cool pools reopen, 19 yes.
20 MR. BLEY: Thank you. And at some point 21 in the future, if you guys have movies about this 22 operation will work it would be real helpful to see 23 that.
24 MR. WILLIAMS: Yes, definitely. Yes. We 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
13 can pull up the 3D model even, and rotate it around 1
and take a look inside.
2 MEMBER REMPE: Is the 3D model sufficient?
3 Or are you planning to do some sort of non-nuclear 4
prototype with all the widgets in there, and practice 5
maintenance as part of your development?
6 MR. WILLIAMS: We will be practicing some 7
maintenance in our test and fill facility. That's 8
designed to go on site in Wyoming as a way of 9
combining both some full scale testing of equipment, 10 as well as the facility needed to fill the actual 11 reactor with cilium eventually.
12 So, in that facility we'll be testing some 13 full scale prototypes. And some aspects of that will 14 be for maintenance operations as well, refueling, and 15 things like that.
16 MEMBER REMPE: Thank you.
17 MEMBER MARCH-LEUBA: While you were 18 discussing the figure, that bright red square on the 19 button, what is it?
20 MR. WILLIAMS: Yes. That's the heated 21 length of the fuel. So, you can kind of sense how 22 small that is compared to the amount of coolant that 23 you have.
24 (Off microphone comment) 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
14 MR. WILLIAMS: Yes.
1 MEMBER MARCH-LEUBA: -- capacity.
2 MR. WILLIAMS: Right.
3 MEMBER MARCH-LEUBA: And the vessel is low 4
pressure obviously. And is on air. It's not in a 5
large cooling pool like --
6 MR. WILLIAMS: Right. You're actually 7
looking at two vessels. And hard to see. But you've 8
got a reactor vessel. And then surrounding that 9
reactor vessel is a guard vessel, and in between that 10 space is interim space using argon gas, so you 11 actually have two vessels there, and outside of that 12 guard vessel is air, and that is what cools the 13 reactor in emergencies, takes care of the decay heat 14 removal.
15 MEMBER MARCH-LEUBA: People contribute 16 sodium and moisture.
17 MR. WILLIAMS: Right.
18 MR. BLEY: Jose, if you can stay on the 19 mic it would help us out here.
20 MEMBER MARCH-LEUBA: I was talking into 21 the mic. So --
22 MR. BLEY: It's clear now. It wasn't 23 then.
24 MEMBER MARCH-LEUBA: After seven years 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
15 here I thought you would understand me. I mentioned 1
that there is no, I don't see any credible path 2
mixture between the sodium and water. Because there 3
is no water.
4 MR. WILLIAMS: Right.
5 MR. BLEY: Yes. Thanks.
6 MR. WILLIAMS: So, on the right of the 7
slide we've got our fundamental safety functions.
8 I'll just touch upon some of the differences here.
9 So, in control I think it's important to 10 point out the motor driven control rod run back.
11 That's something that comes up a lot in discussion 12 energy island transients that we don't need to scram 13 the reactor on. We just need to do a power run back.
14 The control rods are designed to handle 15 those run backs, to avoid the scram. So, that takes 16 into account the transients, the time constants that 17 exist throughout the integrated plans, to be able to 18 run back the power and avoid the scram. So, that's 19 something that we'll be discussing today.
20 There's also of course the gravity driven 21 control rod scram. And then we talked about the 22 inherent reactivity feedback. That's also a form of 23 reactivity control that comes from the design of the 24 core restraint system and the fuel itself.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
16 When we look at cooling, of course we call 1
this an in vessel primary sodium heat transport, or an 2
integrated reactor vessel. Meaning the entire primary 3
heat transport system is contained within the vessel.
4 That means the only primary fluid that 5
leaves this vessel is the cleanup systems, which are 6
small bore pipes that clean up the liquid sodium and 7
the cover gas inside the reactor vessel. All the 8
penetrations go through the reactor vessel head as 9
well.
10 There's also an intermediate sodium 11 system, because the primary coolant isn't leaving the 12 vessel. The intermediate heat exchangers give up heat 13 to an intermediate sodium system that carry the heat 14 out of the vessel and to the sodium salt heat 15 exchangers.
16 And within that system is also another 17 sodium to air heat exchanger that can run in both an 18 active mode and a passive mode.
19 And so, the active mode is what is going 20 to be used when we talk about a lot of the transients 21 today that run back the power down to five percent, 22 isolate from the energy island, and then remove heat 23 with these sodium air heat exchangers, using forced 24 flow mode.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
17 So, that's going to be the typical thing 1
that we'll come back to and refer to as the 2
intermediate air cooling system. It will also work in 3
natural draft flow as well.
4 So, there's some dampers that can open, 5
and just allowing natural draft you can get heat 6
removal there as well. And then the -- Yes.
7 MEMBER MARCH-LEUBA: Let me talk into the 8
microphone. You don't remember a part of your life 9
where you were not working on this design. But to us 10 it's new?
11 MR. WILLIAMS: Yes.
12 MEMBER MARCH-LEUBA: So, please try to 13 explain to us. So, those green heat exchangers I see 14 there are sodium to sodium?
15 MR. WILLIAMS: Yes.
16 MEMBER MARCH-LEUBA: And then the sodium 17 goes outside the vessel?
18 MR. WILLIAMS: The intermediate sodium.
19 MEMBER MARCH-LEUBA: The intermediate 20 sodium --
21 MR. WILLIAMS: Right.
22 MEMBER MARCH-LEUBA: -- goes outside the 23 vessel and heats up the salt?
24 MR. WILLIAMS: That's right.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
18 MEMBER MARCH-LEUBA: And that intermediate 1
sodium can also transfer heat to air in the 2
environment. Is that in site containment or is it 3
outside containment?
4 MR. WILLIAMS: Those exchangers are 5
outside.
6 MEMBER MARCH-LEUBA: Oh. So, it transfers 7
the heat to the environment?
8 MR. WILLIAMS: Yes. It does.
9 MEMBER MARCH-LEUBA: Try to --
10 MR. WILLIAMS: Okay.
11 MEMBER MARCH-LEUBA: You see here to --
12 MR. WILLIAMS: I will.
13 MEMBER MARCH-LEUBA: We don't know this.
14 MR. WILLIAMS: Okay.
15 MEMBER MARTIN: Yes. And I have a 16 question as well. Bob Martin, member. Regarding the 17 air cooling natural draft flow, that is strictly a 18 safety system, right?
19 MR. WILLIAMS: Yes.
20 MEMBER MARTIN:
And during normal 21 operations you would isolate that? No. So, you get 22 parasitic heat losses?
23 MR. WILLIAMS: Yes. And that's okay.
24 That's okay. Yes. Yes. One of the key aspects to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
19 the reactor air cooling system, that's the third 1
bullet under cooling.
2 That's a system that's cooling the outside 3
of this guard vessel using air. Is that it's 4
primarily radiation heat transfer limited. So, it 5
runs on temperature to the fourth power. And so, it 6
takes the primary coolant heating up in order to kick 7
it into operation.
8 So, during normal operation you can accept 9
the parasitic heat loss. Of course, we'd like to sell 10 more electricity with that. But it's okay for the 11 benefit of having it always on, and nothing having to 12 move position or anything to kick it in other than the 13 fluid heats up. So, yes, that's the RAC erector 14 cooling system.
15 MEMBER PETTI: Just a question on the 16 height of the vessel.
17 MR. WILLIAMS: Let me think of the actual 18 number here. I think it's about, yes, between 50 and 19 60 feet tall, yes.
20 MEMBER BALLINGER: This is Ron Ballinger.
21 You're going to get beat up on the prototype versus 22 non prototype issue as we go along.
23 I seem to recall a very long time ago when 24 the French folks discovered that they couldn't find 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
20 the fuel after the irradiation, because of the 1
distortion. And with a constrained core you can limit 2
that I'm assuming.
3 But how do you deal, that's one case where 4
without a test it's going to be tough. Is it going to 5
be tough, do you think, to justify not making a 6
prototype?
7 Because without the irradiation damage on 8
the fuel you won't get the distortion, limited as it 9
might be because of the core restraint system, to 10 verify that the darn control rods will go in when 11 they're supposed to?
12 MR. WILLIAMS: Yes, so a lot of, I mean, 13 our fuel, we're relying on the database provided by 14 the Fastbucks test facility for our fuel, and we've 15 set the design of the Type 1 fuel to be very close to 16 what was used at FFTF for that reason.
17 And then, we're supplementing that with 18 quite a lot of four mechanical tests. We have a lot 19 of full scale tests that look at distortion. We 20 distort assemblies in our facility in Bellview, and 21 look at withdrawal and insertion forces on those.
22 We also do multi assembly core mechanical 23 tests to get additional data on anything that is 24 different with the NATRIUM fuel. And so, I think 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
21 we're relying on the database from FFTF as well as the 1
attesting that we've done got in our plan to make the 2
argument that that prototype isn't needed.
3 And then, to go to our advanced fuel then 4
we need years of operation with a lead test assembly 5
program in NATRIUM to build it back. So, we're 6
starting with the bootstrap method using a fuel design 7
that's very, very close to FFTF.
8 MEMBER BALLINGER: You're satisfied you 9
can make that case?
10 MR. WILLIAMS: Yes.
11 MEMBER KIRCHNER: Eric, this is Walt 12 Kirchner. Just clarification. My memory for FFTF is 13 oxide fuel. Did you have, did they, did Argon send 14 metal fuel for irradiation --
15 MR. WILLIAMS: Yes.
16 MEMBER KIRCHNER: -- experiments or data 17 in FFTF?
18 MR. WILLIAMS: Yes, they did. They did.
19 They were in the process of testing metal fuel. So, 20 they hadn't converted over to metal fuel or anything.
21 So it was an oxide fuel reactor with metal fuel 22 assemblies within it. So, we do have data on that.
23 And we've acquired those assemblies to do PIE on.
24 MEMBER REMPE: Now much fluence did they 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
22 get in FFTF?
1 MR. WILLIAMS: I don't know off the top of 2
my head. You could maybe contact somebody back --
3 MEMBER REMPE: Well, again, this, the 4
purpose of the meeting isn't on that. But that's 5
something to think about.
6 MR. WILLIAMS: Okay. We do have a, 7
George, remind us. We have a fuel qualification 8
topical report right now. Yes.
9 MR. PICCARD: Yes. We have several 10 reports, we just got back the draft form that will 11 talk about the new qualifications methodology and how 12 we're going to go through that, so it will be covered.
13 And it's on future topical reports in more detail.
14 MR. WILLIAMS: Okay. The last fundamental 15 safety function is contain. I don't think we're 16 talking too much about that today, because we're not 17 talking about releases.
18 But we have low pressure systems in the 19 plant. I think we mentioned that already. Low 20 pressure in the primary system that you see here. Low 21 pressure in the intermediate feed transport system, 22 and even in the salt system.
23 So, none of those systems are highly 24 pressurized. You won't get high pressure until you 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
23 all the way out to the steam generating system. So, 1
that helps quite a bit with the containment strategy.
2 We know that sodium has affinity for 3
radionuclides. So, we'll be factoring that into the 4
mechanistic source term analysis. And there's 5
multiple boundaries, you know.
6 There's an intact primary system like you 7
see here. And then there's, you know, a head access 8
area above the reactor vessel head. That's also 9
another layer of protection.
10 CHAIR ROBERTS: Eric, are we looking at 11 the containment right now, this thing, picture beside 12 13 MR. WILLIAMS: Essentially those are the 14 guard vessel surrounding the reactor vessel is part of 15 that.
16 CHAIR ROBERTS: What do you --
17 MR. WILLIAMS: And the seals --
18 CHAIR ROBERTS: -- as containment?
19 MR. WILLIAMS: Yes. So, that's a, it's a 20 series of SSCs that are credited. The guard vessel is 21 part of that. The reactor vessel head is part of 22 that. And the isolation valves on those two systems 23 that come out of the primary system for the cleanup, 24 I think those are also part of that.
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24 MR. WILSON: We'll have a functional, this 1
is George Wilson, TerraPower. We have a functional 2
containment design that will go from some of the EPZ 3
methodologies that we take credit for different 4
portions based on where we're at. So --
5 MR. WILLIAMS: Yes.
6 MR. WILSON: It would follow the SECY 7
paper if that was approved, that SRM that was approved 8
by the Commission on how to describe and go through 9
the functional containment. So, that will be further 10 discussed later.
11 MR. WILLIAMS: So, taking all that into 12 account you have a pretty simplified response to 13 abnormal events. And that group of bullets you see 14 there is really what we would be crediting in say a 15 design basis accident scenario with reliable reactor 16 shut down.
17 Then you transition to natural circulation 18 cooling. You use the reactor air cooling system, or 19 indefinite asset emergency heat removal. You've got 20 the low pressure functional containment. Then 21 there'll be no reliance on the energy island for any 22 safety functions.
23 No safety related operator actions for AC 24 power as well. And we've kind of already discussed 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
25 our basis in the legacy US SFR experience. All right.
1 Go to the next one, Nick.
2 So, this just shows a bird's eye view of 3
the site that's laid out. I think last time we were 4
here we didn't have quite the topology, the way it 5
really looks in Wyoming. So, that's kind of a nice 6
feature that's been added.
7 I don't think anything is significantly 8
moved around though, since we last discussed with you.
9 We're mainly talking about here the, well, if we talk 10 about the nuclear island first, you can see Buildings 11 1, 2, 3, and 4 in the center of the slide.
12 1 is the control building, 2 is the fuel 13 handling building, 3 is the reactor building where the 14 vessel that we saw on the prior side is in the reactor 15 building below grade. And then the reactor ox 16 building, which is Building number 4.
17 We're going to be talking a lot about the 18 equipment in that building today, because we're 19 talking about these energy island transients. And I 20 wanted to point out the question that often comes up 21 is the nuclear island salt system isolation valves, 22 and where they're located.
23 They're actually located at, just outside 24 of Building number 4, in the salt piping that is going 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
26 out to the salt storage tanks. And that's identified 1
with Label 5. 5 shows you the piping train that comes 2
out of the sodium salt heat exchanger, and goes out to 3
the storage tanks that you see on the energy island.
4 So, those isolation valves, there'll be 5
one on the hot side and one on the cold side, those 6
exist just outside of Building number 4, as close as 7
practical to it. So, that's where the break is where 8
we talked about the interface between the nuclear 9
island and the energy island where that break occurs 10 physically.
11 MEMBER HALNON: So, Eric, intermediate 12 cooling, forced cooling, is that the two structures 13 just to the left of the Number 5 circle there?
14 MR. WILLIAMS: No. Those would be close 15 to Building 4. I think it's that grey --
16 MEMBER HALNON: So, it's inside those --
17 MR. WILLIAMS: Yes.
18 MEMBER HALNON: Inside the nuclear island?
19 MR. WILLIAMS: It is in the nuclear island 20 yes.
21 MEMBER HALNON: We just don't see it.
22 MR. WILLIAMS: Yes. You'll see it a 23 little bit better on the next slide.
24 MR. KELLENBERGER: Yes. It's these two 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
27 tan towers to the left of 4. Those are the --
1 MEMBER HALNON: Okay. So, that's the 2
separation you have?
3 MR. WILLIAMS: Right.
4 MEMBER HALNON: Okay. Thanks.
5 CHAIR ROBERTS: This is Tom Roberts. Can 6
you talk some more about those valves? Are they, you 7
know, giant valves that shuts, isolates the flow on 8
that sub pipe? How big a pipe is that?
9 MR. WILLIAMS: It's about a 36 inch pipe.
10 So, it is designed to isolate the salt system, isolate 11 the nuclear island from the energy island. So, when 12 we do our power run back we'll reduce power to about 13 five percent. And then we'll isolate from the energy 14 island. And we'll take care of all the decay heat 15 removal.
16 Say if you're in a, even during an outage 17 for refueling, or something like that. We'll come 18 down and take care of all the heat removal using the 19 intermediate air cooling system, those sodium to air 20 heat exchangers.
21 MEMBER MARTIN: A clarification. Bob 22 Martin. To the right of seven is that like a air 23 cooling ultimate heat sink?
24 MR. WILLIAMS: Yes. That's the forced 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
28 cooling, cooling down --
1 MR. WILSON: It is not an ultimate heat 2
sink. That is just a cooling tower for the turbine, 3
for the condenser.
4 MR. WILLIAMS: Yes.
5 MR. WILSON: That has nothing to do with 6
safety. So --
7 MEMBER MARTIN: I wasn't using the 8
ultimate heat sink as a safety term. Because 9
obviously --
10 MR. WILSON: It just --
11 MEMBER MARTIN: -- heat loss --
12 MR. WILSON: It's condenser cooling for --
13 MR. WILLIAMS: Right.
14 MEMBER MARTIN: I'd like to -- And this is 15 your design? Not just a artist rendering, or anything 16 for --
17 MR. WILLIAMS: Right, yes.
18 MEMBER MARTIN: -- Linkedin, or something?
19 MR. WILLIAMS: Right.
20 MEMBER MARTIN: Last month we were at 21 Comanche Peak. And one of the things that impressed 22 me was just really how compact everything was. And 23 here I see a control room over here on the left in a 24 very linear layout.
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29 And now, part of the, you know, part of 1
the point is all this independence, you know, by 2
seeking. So, it's very obvious where you need to draw 3
a line.
4 But I have to wonder, when it comes to, 5
you know, a big part of your safety case is built on 6
the hazards of, so you're going to have PRA, what have 7
you. You're going to have maybe a fair amount of 8
cabling, electrical.
9 And I wonder whether your, you know, total 10 length of these activities, and just maybe just a 11 thermal inertia that you have there. Plus your pool, 12 your intermittent loop, your salt, and then the steam.
13 And in, so I'm wondering about the 14 responsiveness of the plant overall. Again, an 15 independent, you know, if you're trying to get a 16 dependence you're going to be a lot decoupled.
17 But even, you know, there's a trade off, 18 right, with the responsiveness of the plant. You're 19 going to have something as simple as load follow, 20 which makes your, you know, of course operators 21 impatient. The answer is an automatic control.
22 But all these sort of thing is going to 23 factor into I would say your PRA. And have you 24 considered how the physical layout like this, you 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
30 know, like the linear feet of your cabling and stuff 1
play into that? Is that on your mind?
2 MR. WILLIAMS: It's definitely on our 3
mind. I mean, we have built quite the integrated real 4
F5 model of this plant that takes into account all of 5
these interfacing systems.
6 We're also using that for the engineering 7
simulator, which is starting to come online. So, 8
we'll be running a lot of these transients to see 9
those different time constants and, you know, system 10 interaction type facts that come into play with these 11 things.
12 And right now it's actually looking very 13 beneficial from the standpoint of plant control. And 14 we'll get into a little bit of that when we get to a 15 slide coming up, about the difference between the 16 nuclear island operator and the energy island 17 operator.
18 But I think that that buffer of having the 19 salt tanks in the middle, in between these systems 20 does provide this very good divisional between the 21 two. So, it's not all so tightly coupled, because 22 those tanks kind of buffer things.
23 MR. WILSON: And this is George Wilson.
24 And we also have a human factor's evaluation topical 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
31 report coming in that you guys will get a look at 1
potentially later on, to address some of the comments 2
that you brought up.
3 MEMBER BIER: Yes. That was going to be 4
my follow up. This is Vicki Bier. Which is, so Bob 5
kind of mentioned just the linear feet of cable and 6
your piping, or whatever that may make it vulnerable.
7 But also, are there actions that are going to require 8
people going back and forth between the different 9
locations? Or --
10 MR. WILSON: Right now we're doing -- This 11 is George Wilson. We don't have any safety. We're 12 not taking credit for any operator actions. And we do 13 not have any safety related AC at all on the plant.
14 So the design itself addresses some of 15 your guys' questions, but will also address the human 16 factors. Like I said, there's topical reports that 17 are still being written, that's going to the NRC, that 18 you'll have, and so you will get a chance to have 19 additional questions to that.
20 MEMBER HALNON: Yes. And we went through 21 this in your last presentation about the location of 22 the control room, and whatnot. And you might think, 23 I understand that the picture itself, it's not a 24 quarter mile.
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32 MR. WILLIAMS: Right.
1 MEMBER HALNON: It's a pretty compact 2
plant. So, moving it 100 feet to the right is not 3
going to increase the responsiveness all that much, if 4
any. Because you may have to be walking around 5
buildings or through buildings at that point. So, we 6
did discuss some of this earlier on. So, really good 7
to see how responsive other topicals.
8 MR. WILLIAMS: Yes.
9 MEMBER REMPE: So, I have a different 10 question. I'm not sure if this is the place, or 11 later. But you always emphasize you're building upon 12 U.S. experience. And I'm thinking of the Japanese 13 experience in Monju.
14 And if your, some of this requires 15 instrumentation. And of course the leakage was from 16 somebody putting in a thermal couple that was not, was 17 susceptible to corrosion and leakage.
18 And are you going to have, and I looked 19 through the materials we were given at a different 20 level. But are you going to have some sort of 21 limitations to consider that you aren't going to have 22 some problems in the energy island that, and I'm 23 thinking co-located hazards, that if something were to 24 degrade, and that salt happens to have a problem, and 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
33 people are responding to it, that it might adversely 1
affect the nuclear island.
2 MR. WILLIAMS: Well, I don't, I think, you 3
know, most of the problems that would be initiated in 4
the energy island, you know, would simply result in a 5
power run back.
6 Because you want to, if it's a big enough 7
problem you'd want to shut down the energy island, and 8
go do the repair. I think the good thing about this 9
plant is that you don't have to scram the reactor to 10 do that. You can take a power run back, put the 11 system through a much milder transient, much safer 12 transient to go down in power on the nuclear island.
13 There's also quite a bit of time before 14 you have to do that. We'll talk about it in a minute, 15 which is a big improvement I think.
16 So, I don't, I can't see right now why a 17 maintenance issue or a failing piece of equipment on 18 the energy island would ever impact the safety of the 19 nuclear island.
20 From a reliability standpoint it is very 21 important though. And we are trying to design a very 22 reliable energy island, probably more reliable than 23 what concentrated solar plants would want, or need.
24 So, you know, we want the high capacity 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
34 factors that nuclear plants expect, and so our energy 1
island will be designed with a high level of 2
reliability, so that will definitely be true now.
3 MEMBER PETTI: I understand that the 4
concentrated solar guys, the reliability is not very 5
good. What are you guys --
6 MR. WILLIAMS: Yes. We're looking at the 7
OE from the concentrated solar industry.
8 MEMBER PETTI: I mean --
9 MR. WILLIAMS: We're looking at the codes.
10 MEMBER PETTI: -- sold by them. It's 11 advisory.
12 MR. WILLIAMS: Yes. The codes that 13 they've applied to their systems, and different types 14 of failures that they've seen in the field. So, we're 15 in tune with all of that very closely. So, we're 16 taking that into account in our design.
17 And the interesting thing though is just 18 that that, with their low capacity factors they don't 19 really necessarily need the same reliability that we 20 do. So, that is something that we're paying attention 21 to.
22 MEMBER BROWN: Question. You mentioned 23 there's no safety related electrical systems at all.
24 And yet, the reactor protection system is scram 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
35 supplant as part of the nuclear island. And it's got 1
four divisions. And how do you maintain --
2 MR. WILSON: I meant that --
3 MEMBER BROWN: -- power --
4 MR. WILSON: -- there's no backup. We 5
don't have any safety related diesel generators, or 6
anything like that. We don't have any --
7 (Simultaneous speaking) 8 MR. WILSON: That's right. You'll have 9
RPS. And you also have all the PAMs instruments.
10 MEMBER BROWN: Is there one system set up 11 to have redundant run back capability? In other 12 words, redundant systems to drive those? That seems 13 to be --
14 MR. WILSON: There's logic --
15 MEMBER BROWN: -- the primary thing. So, 16 that's what I'm talking about.
17 MR. WILSON: Yes. There's logic.
18 MEMBER BROWN: Like the SS4 division. And 19 just so the run back obviously is there to bring the 20 power down during operations if you have difficulties, 21 so you don't have to scram.
22 And I was curious. They didn't talk about 23 having any redundant channels or divisions for that.
24 It sounded like a one division, one off sort of.
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36 MR. WILSON: It may be later --
1 (Simultaneous speaking) 2 MR. WILSON: We have a topic report to 3
talk about the nuclear island control system. We've 4
had interactions. And the RPS system will go through 5
the design review guide. But there's multiple 6
channels. And we have logic --
7 MEMBER BROWN: Okay. All right.
8 (Simultaneous speaking) 9 MEMBER BROWN: Thank you.
10 MEMBER MARTIN: There's a question.
11 You've, of course already, George, mentioned, you 12 know, safety related components, what have you. We're 13 safety related this, that at this stage, at least of 14 your interaction with ACRS.
15 As far as I know, not seeing any kind of 16 safety classification methodology. I see, you know, 17 you go through a hazard, a PRA, what have you.
18 There's a methodology to making those claims.
19 All I hear is claims, arguments. But as 20 far as I know have you sent something to the staff 21 that explains the classification methodology?
22 MR.
WILLIAMS:
Yes.
We've had 23 interactions with the staff, and how we've utilized an 24 AI 1804, and how we're doing our SSE classification, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
37 how we're doing our design base and licensing basis 1
events. We've had all those interactions. And we've 2
written topical reports and white papers to the staff.
3 MEMBER MARTIN: Okay.
4 MR. WILLIAMS: So, there's a series of 5
topical reports that we still have to submit to the 6
staff. And the staff has received several topical 7
reports already.
8 MEMBER MARTIN: Okay. Maybe I'll save my 9
question for the staff.
10 CHAIR ROBERTS: Yes, this is Tom Roberts.
11 One more question. And I hope we can get it off the 12 slide. Part of what Joy was asking. Did you look at 13 potentially catastrophic events happening in the 14 energy island, like something, you know, something 15 blows up due to a chemical reaction? Or, you know, a 16 exothermic reaction of the salt with something?
17 I don't know. But, it's I don't really 18 see in the topical reports talk about how that would 19 not affect operations on the nuclear island.
20 MR. WILLIAMS: Well, our licensing basis 21 events are, and our initiating events that we're 22 screening are all driven by failure modes and effects 23 analyses on the equipment.
24 So, we are looking at from a fundamental 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
38 standpoint how each piece of equipment can fail.
1 We're not seeing anything like an explosive reaction 2
in the salt tanks, or anything like that. Because 3
salt isn't interacting with air.
4 You know, if you get a salt leak from a 5
tank it freezes in the air. It solidifies and comes 6
as this white powdery stuff that you clean up with a 7
shovel.
8 We are addressing the potential for 9
flooding from, you know, a catastrophic failure of the 10 tanks using berms that you don't actually see in this 11 diagram. But they would direct the flooding away from 12 the nuclear island.
13 And then it's about, you know, impact of 14 failures, you know, that have to go all the way 15 through the energy island salt piping, through the 16 nuclear island salt piping, and to the sodium heat 17 exchangers, sodium air heat, sodium salt heat 18 exchangers. Through those to the intermediate heat 19 transport system and through the IHX to the primary 20 pool.
21 So, it's all about kind of impact from the 22 energy island and make it through all of that to any, 23 you know, adverse any fundamental safety function, 24 which we're saying it cannot based on our simulations 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
39 that we've done.
1 So, we are looking at things like, you 2
know, salt hammer type events. If those isolation 3
valves close quickly, you know. Things like energy 4
island salt pump trips, and things like that.
5 So, all of those things that can happen on 6
the energy island are being studied. They're part of 7
the design. And we have a design requirement that 8
they shall not impact the nuclear island.
9 So we'll be continuing to, you know, if 10 anything changes we'll be continuing to look at that, 11 but we're not seeing anything like an explosion in the 12 tanks or anything of that nature, because we don't see 13 a precursor for that.
14 CHAIR ROBERTS: Okay. Thank you. Yes, in 15 theory an explosion in the energy island could affect 16 habitability in the control room, or any of a number 17 of direct mechanical effects on the nuclear island.
18 So, I'm glad to hear you're looking at that.
19 MR. WILLIAMS: Yes.
20 MEMBER MARCH-LEUBA: And, Tom, this time 21 I wanted to answer the previous question. Is it okay?
22 MR. ANZALONE: Yes, thanks. Is there a 23 microphone up here? Okay.
24 MEMBER REMPE: I think it's the top one.
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40 MR. ANZALONE: Okay. Thanks. Yes. I 1
just wanted to clarify that we're going to be talking 2
about the safety. Oh, sorry. Reed Anzalone from the 3
staff. We're going to be talking about the safety 4
classification process in our presentation. So, happy 5
to address the question then.
6 MEMBER MARCH-LEUBA: Thank you.
7 MR. WILLIAMS: Thank you. So, just to get 8
off this slide, you know, Building 6 is where the 9
steam generator equipment is. And Building 7 is where 10 the turbine haul is. So, we'll go to the next slide.
11 And this one is looking at the three 12 central nuclear island buildings, as if we're standing 13 at the energy island looking back towards the nuclear 14 island.
15 So, if you're looking, if you ever go back 16 and flip back and forth between the two slides, you're 17 looking backwards to the nuclear island here.
18 So, in the middle you see the reactor 19 building. You can see the reactor vessel, guard 20 vessel. Below grade there, you can see the pipes for 21 the intermediate heat transport system that come out 22 of the reactor vessel head. And they make their way 23 over to the reactor auxiliary building, above grade.
24 And that is where the sodium salt heat 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
41 exchangers live. They're above grade in that 1
building. There's two of them per train. And there's 2
two trains.
3 And so, that's where the intermediate heat 4
transport system interfaces with the nuclear island 5
salt system, and transfers heat from the sodium to the 6
salt.
7 There is also some discussion in the 8
topical report about drainage. You know, in cases 9
where you need to go into a long term outage you would 10 drain. You could drain both the sodium and the salt 11 system from, sodium from that heat exchanger. So, 12 there's drain tanks for both of those.
13 If there was a leak in the sodium salt 14 heat exchanger you would also initiate a drain, so 15 that you could, you know, terminate that interaction 16 between sodium and salt, and go in and take care of 17 the leak.
18 So, the sodium and salt drain tanks are 19 both below grade in the reactor ops building. So, 20 that's where those will be physically located.
21 You can see the salt piping going out to 22 the thermal storage system over there on the left.
23 That is where those NSS isolation valves will be 24 located.
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42 And you can see the intermediate air 1
cooling heat exchanger up at the top there, above the 2
reactor ops building. That's what we call the air 3
heat exchangers of the intermediate air cooling 4
system.
5 It's connected to, there's one of those 6
connected to each of the intermediate heat transport 7
loops. So, there's two of those in the design. And 8
like I said earlier, they can run in forced flow 9
cooling mode, where there is actually blowers blowing 10 air across the coils of the heat exchanger.
11 It can also run in natural draft mode, 12 where the dampers open and just allow natural draft 13 air flow over the coils. And that's the system that's 14 used in a lot of these run backs, and certainly in 15 refueling mode. Yes, question.
16 MEMBER KIRCHNER: Eric, this is Walt 17 Kirchner. A couple of questions. The sodium salt 18 heat exchangers, you mentioned earlier that sodium 19 salt mixtures are exothermic.
20 Since these are solid systems, in terms of 21 solid liquid during normal operation, is there the 22 potential for propagating a, energy back into the 23 primary vessel?
24 MR. WILLIAMS: They're actually not solid.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
43 There is a drain tank in the intermediate heat 1
transport system. So, there's a cover gas on that 2
drain tank.
3 MEMBER KIRCHNER: Yes. I see you have an 4
argon, a pre surface argon cover gas.
5 MR. WILLIAMS: Right. Right. And we can 6
detect the leak in a number of ways. And either 7
initiate a run back, or if it propagates to, you know, 8
a loss of heat transfer at the IHX, then it would be 9
picked up by one of the scram set points in the 10 nuclear island, if that were to happen.
11 MEMBER KIRCHNER: I'm not so much worried 12 about it leaking into one of your compartments.
13 Although that would be a concern from a fire 14 consideration.
15 But my concern would be, any energy 16 transfer due to an exothermic reaction between the 17 salt and the sodium. That could pressurize the 18 system.
19 MR. WILLIAMS: Yes. That is something we 20 are looking at though. That will be looked at in our 21 models for any sort of pressure wave that could make 22 its way back to the IHX. So, that would be something 23 that we would definitely look at.
24 MEMBER KIRCHNER: Yes. I think that would 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
44 be important. The other Achilles heel these systems 1
in the past has been the air cooling system for decay 2
heat removal.
3 So, can you tell us a little bit more 4
about this? This intermediate air cooling, is that 5
sodium to air?
6 MR. WILLIAMS: That's right. Sodium to 7
air. So, you have your intermediate heat transport 8
loop. And you have a leg that comes off of the main 9
pipe. And it goes out to this sodium air heat 10 exchanger. Like I said, there's one in each loop.
11 And it's always running through there.
12 And so, what needs to happen is, for natural draft air 13 cooling the dampers would open to allow more air to 14 flow. If it's going into forced cooling mode then the 15 dampers open and the blowers turn on to remove heat 16 from that heat exchangers.
17 So, it's one of the workhorse components 18 that we have. Because it's always used in a run back.
19 It's always used as the main go to system for taking 20 care of decay heat when you're not in a, you know, 21 emergency situation.
22 MEMBER KIRCHNER: Right. So, this system 23 would have isolation valves on it should you get a air 24 a leak to air. I mean, the concern would be a fire or 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
45 other energetic events that could result from leaks in 1
the system.
2 MR. WILLIAMS: Yes, yes. If there were to 3
be a leak in the system that would probably be a drain 4
dilute kind of situation.
5 MEMBER KIRCHNER: Okay. Thank you.
6 MEMBER MARCH-LEUBA: You mentioned the 7
intermediate air cooling has AC power blowers? But 8
they're not required for decay heat.
9 MR. WILLIAMS: Right.
10 MEMBER MARCH-LEUBA: Only during --
11 MR. WILLIAMS: Right.
12 MEMBER MARCH-LEUBA: -- the low power.
13 MR. WILLIAMS: Right, yes. Only during 14 low power --
15 MEMBER MARCH-LEUBA: The decay heat safety 16 removal is the air ducts?
17 MR. WILLIAMS: Yes. It's the air ducts.
18 So, that would be reactor air cooling ducts. You're 19 seeing two of them there in the reactor building.
20 MEMBER MARCH-LEUBA: So, I'm going back to 21 my, everything above grade is susceptible to missiles 22 that can impact. You can live without that? Can you 23 live without the air cooling ducts?
24 MR. WILLIAMS: We can live without a 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
46 certain, we can take a certain amount of degraded 1
performance in the reactor air cooling system. It's 2
actually very robust in fact to say pressure drops and 3
things like that.
4 As long as you have that radiation heat 5
transfer going between the guard vessel and the 6
reactor vessel, then the system performs very well.
7 We will, I mean, obviously be quantifying how much 8
degradation we can handle.
9 And, you know, in the PRA, you know, 10 looking at, it's part of the aircraft impact analysis 11 that we have to do, so there's a lot. At some point, 12 you can, you know, block up all the air ducts, and 13 then, you know, you'll probably bring in some 14 equipment from off site to unblock the duct or 15 something, you know, in that beyond design basis 16 regime, but we're still working through all that.
17 MEMBER MARCH-LEUBA: You mentioned time 18 constant will play a significant factor; you're 19 talking --
20 MR. WILLIAMS: No, yes. Right.
21 MEMBER HALNON: Eric, one last question.
22 Since the fuel is in sodium, the spent fuel's in 23 water, can you just talk to me about how that 24 transition is done, so that you don't get a problem --
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
47 MR. WILLIAMS: Oh, yes.
1 MEMBER HALNON: -- when you insert it in 2
water?
3 MR. WILLIAMS: Storage, yes. That's very 4
carefully. So, fuel comes out. Obviously, I should 5
have mentioned this. But the fuel actually goes into 6
an in vessel storage location outside of the reactor 7
core barrel when it is done in the core.
8 And it cools off there for a cycle, inside 9
the vessel, before it even comes out. So that's a, 10 you know, a unique feature I think of a lot of sodium 11 bass reactors, pool reactors especially I think.
12 So, it cools off a little there, comes out 13 of the vessel. And then it gets transferred to an X 14 vessel storage tank, which is filled with sodium. And 15 it goes there during the outage. And you collect all 16 of your assemblies there.
17 And then after the outage you go in and 18 process them. And what you would do to put them into 19 the spent fuel pool is, you would take them out, and 20 they would go through a pool immersion cell, PIC, 21 which is a pit. It's probably one of those that you 22 see below grade over in the field handling building.
23 And it goes into that container. And what 24 we do is we blow initially dry nitrogen over that, to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
48 just blow off any sodium that is remaining, and 1
gradually turn up the humidity on the nitrogen very 2
slowly and carefully until any water in the nitrogen 3
is able to react with the sodium in any crevices or 4
things like that, until it's all removed.
5 And then finally when that is performed it 6
gets moved over to the spent fuel pool. So, and 7
during that whole migration, you know, it is handled 8
very carefully, taken through systems that have 9
barriers between it and air through inerted 10 environments, so that there's no chance of contact 11 with, the sodium on the fuel assembly with the air in 12 the reactor.
13 So yes, sometime I'm sure we'll go through 14 that whole process in detail. Yes. All right. I 15 think that --
16 CHAIR ROBERTS: This is Tom Roberts. I 17 was going to point out that we're about 40 minutes 18 into, essentially into the presentation with five 19 slides done. So, just --
20 MR. WILLIAMS: Okay.
21 CHAIR ROBERTS: -- keep that in mind and 22 try to maybe pick up the pace a little bit, and hold 23 the questions if possible. Thank you.
24 MR. WILLIAMS: Yes.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
49 MEMBER REMPE: We always blame the 1
Subcommittee.
2 MR. WILLIAMS: Okay. So now we're looking 3
back towards the energy island. You can see in the 4
picture to the right the energy island salt piping 5
that's coming back.
6 You've got pipes going from the cold salt 7
tank that go back to the nuclear island. And pipe 8
that goes from the sodium salt heat exchanger to the 9
hot salt tank. So, they're all contained within that.
10 One thing I wanted to point is, you see 11 several of the green lines that are coming, going into 12 the steam generator building. That's because we have 13 five steam generator trains, and the hot salt tank has 14 five pumps that go into, one per steam generator 15 train.
16 Off the cold salt tank, you also see quite 17 a few pumps and lines there. That's the attemperation 18 pumps that come off of the cold salt tank and go over 19 and mix into the salt coming out of the hot salt tank.
20 And then you can see a process flow 21 diagram down there at the bottom left. A lot of the 22 typical equipment that you see in a steam generator is 23 contained on this.
24 There are again five of these steam 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
50 generator system trains. So, if we just take from the 1
left to the right, you can see hot salt coming out of 2
the tank there.
3 It goes into both the super heater and a 4
reheater. The reheater takes some cold reheat from 5
the turbine extraction, and sends it back as hot 6
reheat.
7 The evaporator starts to bring the 8
feedwater up to saturation in the steam drum. And 9
then that goes over to the super heater to super heat 10 the steam, and send that off to the turbine.
11 We also use some of the salt to preheat 12 the feedwater over there on the right. And so that 13 essentially completes that circuit.
14 We have looked at, you know, transients 15 where you lose that cold salt, that salt return to the 16 cold salt tank. And we can go quite a bit of time 17 without that cold salt return before we have to do 18 anything on the nuclear island to adjust power, or 19 take the plant down, rather.
20 So, that is something that we've looked at 21 with our transient analysis. And we'll continue to 22 be, you know, checking that as we go through the rest 23 of the design.
24 MEMBER HALNON: Are the two tanks, hot and 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
51 cold, are they identical?
1 MR. WILLIAMS: Yes.
2 MEMBER HALNON: And so the same?
3 MR. WILLIAMS: Yes.
4 MR. SCHULTZ: Eric, the transient analysis 5
that you did associated with the Energy Island, those 6
calculations are done with what methodology? Staff 7
had some comments during their audit associated with 8
the pedigree of the evaluation.
9 MR. WILLIAMS: Yes. Those were done as 10 part of our integrated plant analysis
- work, 11 specifically looking at all of the ASME design 12 transients, level A, B, C, D. And some of those then 13 get run over in the SAS code as part of looking at 14 these transients from a DBA perspective.
15 So we kind of used the best estimate 16 methodology to look at the ASME design transients and 17 then those factor in. If something like that were to 18 make its way into a DBA, then we would look at a 19 different methodology for safety analysis.
20 The transients that were looked at by the 21 staff, I think we had one calculation that used SAS, 22 but most of them were using 3D.
23 MR. SCHULTZ: Okay. The staff just 24 mentioned that they hadn't taken a look at those in 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
52 terms of code review and so forth.
1 MR. WILLIAMS: Okay.
2 MR. SCHULTZ: That could be something that 3
is done in the future?
4 MR. WILLIAMS: Yes.
5 MR. SCHULTZ: Thank you.
6 MR.
WILLIAMS:
Yes.
Those were 7
preliminary. This topical report, which was submitted 8
in October of '22, was based on a conceptual design of 9
the plant.
10 So I think it did a really good job of 11 showing us these various time constants that exist in 12 the system and how robust the design is to have this 13 sort of independence between Energy Island and Nuclear 14 Island. We know that we will be repeating these 15 analyses as we proceed through the design.
16 MR. SCHULTZ: The staff mentioned all that 17 in their audit report and also came to the same 18 conclusions regarding the results. Thank you.
19 MR. WILLIAMS: All right. Let's go to the 20 next slide. We'll talk a little bit now about 21 operational flexibility. These are really the talking 22 points for the next slide, so why don't I just speak 23 to this as we look at the picture on the next slide.
24 We're kind of seeing two sides of the view 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
53 here. The side on the left is the view from the 1
Nuclear Island operator and the side on the right is 2
from the view of the Energy Island operator.
3 On the Nuclear Island side, we're going to 4
have licensed reactor operators controlling reactor 5
power. This allows the Nuclear Island operator to 6
really focus on the safety of the plant.
7 As long as the cold salt tank is flowing 8
appropriately into the sodium-salt heat exchangers, 9
we're not going to be affecting any of what we call 10 the interface parameters between the Energy Island and 11 the Nuclear Island that would cause a scram or 12 anything like that. So that's kind of the view from 13 the Nuclear Island standpoint.
14 From the Energy Island standpoint, the 15 grid operator is able to then control the turbine to 16 meet the electricity demand of the grid. As long as 17 the Energy Island operator is managing the inventory 18 between the hot and cold salt tanks, they won't be 19 triggering a runback.
20 They can manage that any way they want.
21 They can turn back electricity production. They can 22 increase electricity production. Whatever is required 23 to maintain a certain minimum cold salt tank level, 24 they can do that without recourse through the Nuclear 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
54 Island.
1 And so one of the things we look at is 2
what does that cold salt tank minimum level need to 3
be. For example, you would take the height of salt 4
required to provide net positive suction head to the 5
cold salt pumps.
6 Add to that the amount of salt that you 7
need to do a runback, to consume the runback, and add 8
to that the amount of salt you need to consume to 9
isolate the two systems from one another. And then 10 say to the Energy Island, don't go below that.
11 That would be a way of giving that Energy 12 Island operator flexibility to meet the grid demand 13 without impacting the Nuclear Island at all, and 14 always maintaining the reserve that you need to do a 15 proper runback without having to scram the plant.
16 MEMBER HALNON: Eric?
17 MR. WILLIAMS: Yes.
18 MEMBER HALNON: When everything is working 19 right, that sounds great. What happens when, say, the 20 dispatch calls for more power than what the Energy 21 Island can produce?
22 Are those controls and limits things that 23 cause some kind of action? You can control your 24 operators on-site and you can train them, but you're 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
55 not going to train the dispatcher.
1 MR. WILLIAMS: Yes. That all has to be --
2 control bands, alert levels, response times, all of 3
that has to be factored into what the grid operator is 4
doing. I don't know if we want to say any more about 5
how the grid operator would react to those things.
6 At some point they hit a limit and they 7
can't provide any more electricity. Or if they're up 8
at the maximum electrical output of 500 megawatts 9
electric and the grid still demands more but they've 10 depleted the hot salt tank, then they would have to 11 dial that back.
12 MEMBER HALNON: I guess I was more 13 thinking of low-power operation where you're a little 14 overambitious in saying, you've got a big hot salt 15 tank there. I can grab more than what you're 16 producing right now and hopefully meet the curve 17 somewhere in the middle before you run out of hot 18 salt.
19 We can talk later, but it would be 20 interesting to talk through those types of scenarios 21 to see how the systems would react. It's probably 22 controls on the Energy Island to find the dispatch, 23 but that interface was a big deal in commercial 24 reactors between the grid operator and the control 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
56 room.
1 MR. WILSON: This is George Wilson. We 2
have monthly meetings with PacifiCorp to go over this.
3 We talk with their compliance people and their grid 4
people. We're coordinating all this now and looking 5
at it.
6 We haven't finalized the procedures, but 7
we're starting to talk about compliance because it's 8
also new for them to get a nuclear plant on their 9
grid. There's additional standards that are going to 10 apply to them now. So we're still working with them, 11 doing the coordination. George's group is leading.
12 MEMBER HALNON: I guess my point is if 13 there's some things beyond your control that you need 14 to look at from the Energy Island and how that might 15 affect the Nuclear Island.
16 MR. WILLIAMS: That's a good point.
17 MEMBER KIRCHNER: This is Walt. Just to 18 kind of add onto your line of questioning, Eric or 19 George, could you give us a feeling of what's the net 20 output from the reactor versus the net output from the 21 steam plant, from the Energy Island?
22 And what's the time constant between the 23 two? Where I'm going with this is, what's the steady 24 state, and then what would be the peaking factor? How 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
57 would that feed back on the reactor system?
1 Or Greg went through a scenario where 2
you're dumping, you're reducing power. You mentioned 3
500 megawatts of electric for the Energy Island.
4 What's the equivalent from the reactor? How much can 5
you store?
6 How are you sizing that hot tank such that 7
when you look at that operational interface, you're 8
going to have a time constant that will run the 9
reactor itself up and down in terms of thermal 10 transients?
11 MR. WILLIAMS: So the design is for the 12 reactor to run a steady-state, full-thermal power.
13 We're not cycling back to any sort of load following.
14 We're doing the load following purely on the Energy 15 Island side.
16 MEMBER KIRCHNER: Yes.
17 MR. WILLIAMS: So in thermal equilibrium, 18 the reactor is putting out the equivalent of 345 19 megawatts electric. And the Energy Island is 20 providing 345 megawatts electric to the grid for a 21 period of time, between four or five hours let's say, 22 you can go up to 500 megawatts electric or you can go 23 down to 100 megawatts electric.
24 If you're in a daytime scenario and all of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
58 the renewables are online and you want to dial back 1
the system, you can dial it back as low as 100 2
megawatts electric. That's just a limitation of your 3
turbine design.
4 You can change that, if you want, with a 5
different design. All of the equipment beyond those 6
tanks are designed in size for 500 megawatts electric, 7
whereas all of the equipment on the Nuclear Island 8
side before the tanks is all designed for 345 9
megawatts electric.
10 MEMBER KIRCHNER: Okay. Thank you.
11 MEMBER MARCH-LEUBA: From the top of your 12 head, in units of power for 500 megawatts electric 13 operation, how big is the hot tank? Four hours, 12 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br />, 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />?
15 MR. WILLIAMS: Yes. It's between four and 16 five hours.
17 MEMBER MARCH-LEUBA: Only four to five 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />?
19 MR. WILLIAMS: Yes.
20 MEMBER MARCH-LEUBA: For the renewable 21 it's 12, right? The nighttime is 12?
22 MR. WILLIAMS: Right, but the peaks really 23 only last for that period of time. The peak in the 24 evening and then the peak in the morning, we have 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
59 people that are waking up. Yes.
1 MEMBER MARCH-LEUBA: Obviously, it doesn't 2
compromise the tanks?
3 MR. WILLIAMS: Right, no. That's 4
optimized for Wyoming. If you went to somewhere else, 5
you might have a different --
6 MEMBER MARCH-LEUBA: And you would just 7
have to change the size of the tanks?
8 MR. WILLIAMS: You can change the size of 9
the tanks. You can have additional pairs of tanks if 10 you need more storage. You can have additional 11 turbines if you want lower turndown.
12 There's a lot of optionality on the Energy 13 Island and a lot of flexibility. It's the Nuclear 14 Island we want to standardize and run full-power all 15 the time. So yes, very flexible.
16 MEMBER MARCH-LEUBA: Do you envision 17 having to sell megawatts electric at a loss? There's 18 sometimes in which nobody wants your power.
19 MR. WILLIAMS: Right, yes. We're not 20 designing for that.
21 CHAIR ROBERTS: Following up on Greg's and 22 Jose's questions, it looks like from the reactor 23 safety perspective, your biggest concern would be a 24 low demand, which is going to basically drain the cold 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
60 tank and fill the hot tank. Is there some minimal 1
level that is essentially a tech spec that if you go 2
below that, you do have a reactor safety concern?
3 MR. WILLIAMS: I think the power runback, 4
what happened before that. I'm sure there are even 5
lower limits that would be tech specs on the tanks 6
perhaps.
7 CHAIR ROBERTS: Tech spec would seem to 8
imply safety-grade instrumentation and that kind of 9
thing to measure it. I was trying to understand how 10 you can maintain the separation when the cold tank 11 level really is a factor in reactor safety.
12 MR. WILLIAMS: Yes. I guess in a future 13 slide here we're going to talk about the interface 14 parameters a bit. And actually, on this next slide is 15 where we have them listed. These are the things that 16 we would be looking at from a safety perspective.
17 If you go to the next one here, this is 18 where we start talking about separation. These are 19 the parameters that we really think of in terms of 20 something that would start to have an effect, would 21 start to propagate through the IHD and then to the 22 PHD.
23 We've looked at all the failures that 24 could occur out there in the Energy Island, all the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
61 way to complete loss of salt flow, which is probably 1
the most bounding of all of them. Just have all of 2
the salt tanks stop running. That would be even worse 3
probably than hitting a low level in the tank or 4
something like that.
5 And so they all come down to either a loss 6
of or reduced heat removal from the intermediate heat 7
transport system because of something that happened 8
out in the Nuclear Island salt system or an increase 9
in heat removal on the intermediate heat transport 10 system.
11 And so these are the parameters that we 12 would probably be looking at more, not so much the 13 tank levels but things closer to the sodium and salt 14 heat exchanger, such as a loss of salt flow that would 15 be detected in the Nuclear Island salt system, a high 16 salt temperature coming out of the sodium-salt heat 17 exchanger, or low salt pressure that might indicate a 18 leak.
19 On the increased heat removal side on the 20 IHD, you can have increased salt flow from a pump 21 over-speed condition or low salt temperature that 22 might be introducing an overcooling transient on the 23 primary system.
24 So these are actually the parameters that 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
62 we would look at. They kind of decouple ourselves, if 1
you will, from the Energy Island. Things that happen 2
on the Energy Island can be taken care of by the 3
Energy Island operator. They can be taken care of 4
with power runbacks.
5 You would have to propagate out to these 6
parameters to start impacting the primary system 7
through all those time constants. And so when we ran 8
our transients and showed those to the staff, we were 9
looking at transients and examples of these different 10 parameters that get triggered.
11 And then you have things even further out 12 beyond the tanks like turbine trips, steam generator 13 malfunctions, equipment like that that would be 14 further away from the sodium-salt heat exchanger that 15 would probably start to trip equipment on the Energy 16 Island due to asset protection, and eventually would 17 trigger one of the runbacks at points to go back and 18 run the system back normally.
19 MEMBER PETTI: I don't think you answered 20 the question. I understand these events, what they 21 could do, and how they could challenge it, but I 22 thought Tom's question was the case of low power and 23 the salt level in the cold tank is also really low.
24 It's sort of an operational condition that 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
63 you could somehow get into a different problem. I 1
guess I didn't see how these transients capture that 2
question.
3 MR. WILLIAMS: Yes. If we think about 4
operating the plan and delivering electricity from the 5
grid where you've depleted the cold salt tank level 6
down to the lowest that you're allowed, you would 7
still have, based on what I was talking about a few 8
slides ago about sizing that minimum level, you would 9
still have enough salt to do the runback and to 10 isolate the system and still have enough for net 11 positive suction ahead of the pumps.
12 So that level was designed to only allow 13 the Energy Island to operate when it's reserving that 14 amount of salt to go ahead and do a runback of the 15 plant. It's not designed to go below that.
16 That kind of gets back to Greg's question 17 over there. You would have to stop producing 18 electricity if you got to that level. You'd have to 19 manage that inventory within the limits provided to 20 the Energy Island.
21 MR. WILSON: This is George Wilson. We 22 haven't developed it but we'll develop system 23 operating procedures, conditions, and limits. It'll 24 be in those system operating conditions and limits 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
64 that you'll have normal operating bands. We just have 1
not done those.
2 So to address your question fully, all 3
that stuff will be covered when we have our operating 4
procedures when we've completed them.
5 MEMBER HALNON: And that comes back, 6
George, to a fundamental question on the operator.
7 Even though you say that there's no events that the 8
operator has to respond to, is there a condition where 9
the operator is required to maintain a certain 10 operating envelope to maintain pre-existing conditions 11 so that no response is such as required?
12 The fundamental question is if they're 13 required to keep it within an operating band, is the 14 operator not in essence responding to a license-based 15 event by maintaining the operational boundaries, if 16 you will, in place?
17 MR. WILLIAMS: This is George Wilson. If 18 you do it by design, I can have design intake have the 19 systems take action. I wouldn't have to rely on an 20 operator. It would be a fall-back, but I could have 21 the system take action. As Eric was saying, transient 22 runbacks and you essentially get a scram.
23 George, did you want to add?
24 MR. PICCARD: Yes. George Piccard from 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
65 plant operations. I will just add to that there is 1
little difference in how you would maintain with a 2
design margin and then an operational margin and other 3
types of operational primers of the amount of salt you 4
want to reserve in the cold tank.
5 You have to have a certain amount of water 6
in the tank. It would be the same type of procedural 7
guidance. You would have a design basis and then an 8
operational margin.
9 Some additional operational margins before 10 you load the dispatcher to actually control anything, 11 you would have even more margin to how much salt 12 reserve you'd have in the cold tank. You wouldn't 13 allow them to be able to control the turbine during 14 start-up or shut-down or any type of other transient 15 or any type of maintenance.
16 There would always be an override where 17 the operators have to give control to the load 18 dispatcher to be able to control the turbine. Any 19 signal that comes from the plant would override 20 anything that came from the load dispatcher. They're 21 not going to be able to control the turbine any time 22 that you don't want them to control the turbine.
23 MEMBER HALNON: Okay. Well, I think we'll 24 explore it more but again, a combination of operating 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
66 procedures, technical specifications, operator 1
training, and system interactions with those operators 2
pre-existing, pre-transient conditions. You have to 3
set up those conditions. It would be an interesting 4
period of discussion when we get into the operators.
5 MR. PICCARD: There would be a tech spec 6
probably for the minimal amount of salt in the cold 7
tank. Remember that's only there to allow the worst-8 case scenario runback to allow you get below five 9
percent power. Not a whole lot of heat is required 10 for that. It doesn't have anything to do with the 11 safety case.
12 MEMBER HALNON: There's no effect from the 13 Energy Island to the Nuclear Island, yet this is an 14 effect. So we have to explore that connection and how 15 that impacts the safety. Okay. I've got a clear 16 picture of where we're going. Thanks.
17 MEMBER REMPE: Just a note of procedure.
18 When you're not up front, you need to say your name 19 every time you talk for the court reporter. And you 20 probably should say it now. Thank you.
21 MR. PICCARD: That was George Piccard.
22 MR. WILLIAMS: Okay. I think we can move 23 a little quicker. The next three slides are really 24 background type of information just to show and talk 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
67 a little bit about that we do have a robust procedure 1
following NEI 18-04 to identify licensing basis 2
events.
3 And so the events that we've talked about 4
here would all be initiating events screening. That 5
would be looked at as part of the PRA. We're really 6
talking about those events in the green shaded region 7
here mostly today. This is a nice slide that reminds 8
us of all of the different families of events that are 9
out there being considered.
10 So the next slide shows us the defense 11 line scheme that we use on NATRiUM. I don't think 12 defense lines come directly from NEI 18-04. They're 13 more of a TerraPower methodology for being able to 14 consider defense-in-depth adequacy in the earliest 15 design phases.
16 So looking at defense lines, tracking them 17 as design requirements in our configuration management 18 of the design has really helped the safety analysts, 19 PRA people, and the engineers on the design really 20 being able to talk the same language.
21 When we look at these defense lines, we're 22 going to see a lot of the Energy Island systems, the 23 runback taking care of Defense Line 2 functions, but 24 no Defense Line 3 or 4 functions on the Energy Island.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
68 That's part of the independence that we have in the 1
design. The Defense Line 3 is where the safety 2
systems are. The Defense Line 4 is more of the 3
mitigation systems.
4 And then the next slide kind of shows a 5
little bit of what we were talking about there and a 6
framework for thinking about Energy Island event 7
responses versus Nuclear Island event responses and 8
how we look at deterministic safety analysis.
9 A lot of the typical events that you would 10 think of in an operating nuclear power plant that 11 happen on the balance of the plant side, those same 12 type of events on NATRiUM would really have no impact 13 on the Nuclear Island. They can't really affect the 14 Nuclear Island until an interface parameter like we 15 were talking about on the prior side gets triggered.
16 And in all cases, if the defense line 2 17 function fails, like the runback is designed to happen 18 but it doesn't happen fast enough, there's still the 19 reactor protection system set points on the Nuclear 20 Island to protect the reactor. So there's always that 21 defense line 3 protection in the plant.
22 All right. This one really talks about 23 the types of transients that we looked at. They all 24 fall into that decrease or increase in heat removal 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
69 from the Nuclear Island salt system.
1 And it's really the thermal inertia and 2
the intermediate heat transport system and the primary 3
heat transport system that provides the adequate time 4
to respond to the event via signals monitored within 5
the Nuclear Island.
6 So in fact, I think the deterministic 7
safety analysis will look at a pretty extreme loss of 8
heat transfer at the sodium-salt heat exchanger and 9
really use that to bound any possible thing that could 10 happen on the Energy Island, and show that the reactor 11 is designed with adequate safety margin.
12 We looked at a couple of transients in 13 detail here. The power runback, which is really 14 something that we want to perform to avoid the scram, 15 begins with reactor power being decreased by the 16 insertion of control rods at a predetermined rate.
17 And being able to do that -- there's 18 different timing that can happen with that. We're 19 designing those control rods to be able to perform 20 that runback in time to avoid the scram.
21 That involves looking at a lot of 22 different transients. Depending on how the runback 23 gets triggered, there's different time constants and 24 different interactions between the systems. We're 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
70 making sure that the control rods are designed in all 1
cases to avoid that scram.
2 Then the IAC and RAC provide the system 3
heat removal. These are what would normally happen in 4
the plant. We're not talking about DBA-type 5
assumptions here. We have both intermediate air 6
cooling and reactor air cooling able to provide heat 7
removal.
8 The primary sodium pump and the 9
intermediate sodium pump get decreased through their 10 targeted flow settings as part of the power runback.
11 And then finally, when you get down to about five 12 percent power, then you isolate from the Energy Island 13 using the NSS isolation valves.
14 In the case of a scram, if one of the 15 reactor protection set points gets triggered, then the 16 reactor power gets decreased. The control rod is 17 dropped by gravity, in this case, as opposed to 18 running them in on the motors.
19 The IAC and RAC also provide heat removal 20 here. The PSPOPs get ramped down. And then you 21 isolate when you get down to five percent power.
22 If we were to look at this same transient 23 from a DBA perspective, then you wouldn't take credit 24 for the intermediate air cooling. You would only take 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
71 credit for reactor air cooling. Instead of the PSPOPs 1
ramped down, they would be coasting down. And we 2
don't take credit for the NSSI isolation.
3 These are kind of the scenarios that were 4
included in our transient analysis that we showed the 5
staff and the different examples of each of these that 6
were presented.
7 MEMBER MARCH-LEUBA: Is only the scram 8
safety grade?
9 MR. WILLIAMS: Only scram is safety grade.
10 MEMBER MARCH-LEUBA:
What are the 11 implications with ATWS? We cannot get to the reactors 12 by designing that scram very reliable. Is there more 13 than one way of getting the rods in? Do you have a 14 way to push the rods in if they don't go by gravity?
15 MR. WILLIAMS: Yes. We have a scram 16 follow function. That is also motor-driven here.
17 MEMBER MARCH-LEUBA: Is it safety grade?
18 MR. WILLIAMS: I am not sure.
19 MS. YOUNG: This is Emily Young from 20 TerraPower. The scram follow function is one of our 21 DL4 functions for our defense-in-depth. If our 22 gravity drop doesn't work for whatever reason, then 23 we'd go into that feature.
24 So it's not necessarily going to be a 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
72 safety-related feature. It's just going to be a 1
defense-in-depth adequacy feature for us.
2 MEMBER BROWN: I thought the topical 3
report read that if you scrammed, you automatically 4
initiated the drop-in. That's the way I read it. If 5
I read it wrong, just tell me, but that's what I saw, 6
that there wasn't a differentiation.
7 MS. YOUNG: This is Emily Young. I'll 8
double check and get back.
9 MEMBER BROWN: Okay. That's the best way 10 to do it. You don't want to wait until you don't have 11 any rods.
12 MEMBER MARCH-LEUBA: The question I was 13 going to mention is to eliminate errors from your 14 analysis, you have to demonstrate that your scram is 15 on the line of 5 or whatever number you choose. So I 16 guess it's only if the components are safety grade.
17 MEMBER MARTIN: Real quick, what power 18 level does the Energy Island generate power to the 19 grid?
20 MR. WILLIAMS: You mean during start-up?
21 MEMBER MARTIN: Yes, during start-up.
22 Obviously you would have a procedure unlike what it is 23 for shutdown.
24 MR. WILLIAMS: George, our start-up 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
73 narrative?
1 MR. PICCARD: Yes. George Piccard, 2
TerraPower. The way the start-up narrative currently 3
reads is that we would actually put the steam 4
generators into a hot standby mode.
5 You don't need to necessarily have the 6
same type of -- get to a certain power and then roll 7
the turbine. You would have a light-water reactor 8
typically at maybe 25-30 percent power.
9 Depending on where the salt tanks were 10 whether you had a long shutdown or a short shutdown, 11 you could bring the reactor up to power, low power.
12 You could stay on the intermediate air cooling system 13 or you could put more heat into the salt tanks.
14 So there's a lot more flexibility in the 15 start-up than you would have at the light-water 16 reactor. I don't think right now we actually know 17 when is the ideal time to start rolling the turbine at 18 what power level, but I would imagine it would be 19 similar, 20 percent to 50 percent power.
20 You'd want to start putting your heat 21 somewhere. So it's just a matter of how much capacity 22 you have for where your heat goes and when you want to 23 start using it.
24 If you don't want to roll your turbine and 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
74 you still want to bring the power up, we also have 1
steam dump valves. So there's a tremendous amount of 2
flexibility of when you actually want to start 3
generating electricity. You just don't have to do it 4
at a certain point during start-up.
5 MEMBER BROWN: Is this Nuclear Island a 6
true nuclear island? You don't even need the Energy 7
Island at all; it can support itself?
8 I thought all the electrical power that 9
was generated in the Energy Island is not self-10 supporting. Is it independent?
11 You don't have to have the grid to run the 12 plant, but you have to have the Energy Island to 13 operate the plant without electricity, but you don't 14 have any diesel generators.
15 So there's some point in here where you 16 need other power for doing something, I would think.
17 It sounds like if all the lights go out, you don't 18 care anywhere in the entire, whole plant.
19 MR. WILSON: This is George Wilson. We 20 have a diesel generator. It's not safety grade.
21 MEMBER BROWN: Okay.
22 MR. WILSON: I don't have any safety-23 related backup power.
24 MEMBER BROWN: That's fine. What I was 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
75 really getting to is you don't have to have the grid 1
in order to operate via a stable, low-power 2
conditioning. You're self-supporting?
3 MR. WILLIAMS: Yes. You can dump the 4
steam, I think, which is what George was saying there.
5 MEMBER BROWN: As well as run your 6
turbines, if you needed to. You could generate your 7
own electrical power from the Energy Island; is that 8
correct also?
9 MR. WILSON: This is George Wilson. We're 10 going to re-validate it if we're going to backfeed 11 from generator output back and give houseloads back 12 into what you can.
13 That is something that's still being 14 evaluated where we'll potentially backfeed in there.
15 Right now our sodium pumps would be powered from the 16 grid. So if you would lose the grid, you would lose 17 your sodium pumps.
18 MEMBER BROWN: All right. Thank you.
19 MEMBER KIRCHNER: This is Walt Kirchner.
20 Along those lines, you initially had indicated five 21 steam generator trains. Have you decided on your 22 turbine equipment yet?
23 If you had five turbines -- I'm not saying 24 that's what you're doing -- you could do a cold blast 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
76 start of the plant by yourself without off-site power.
1 MR. WILSON: This is George Wilson.
2 That's something that we've talked with some people 3
that are interested in our plant, actually doing a 4
backfeed and doing a cold start off of our salt tanks.
5 That's not something that we've put into the design 6
yet, but that is something we're evaluating.
7 MR. WILLIAMS: Emily, you want to add 8
something?
9 MS. YOUNG: Yes. Emily. Again, a point 10 of clarification, you are correct. The scram follow 11 would initiate immediately following a scram signal 12 generation, correct. Scram follow, yes, for freezing.
13 And then also there was a question about 14 unprotected events. I just want to make a point of 15 clarification that we do have some unprotected events 16 that we are looking at for the LMP process in terms of 17 discussing the cliff edge effect, but those are 18 currently screened out of our BDBE region.
19 Their frequency is what we're clarifying 20 as an OQE, an other quantified event. So we will look 21 at those.
22 But the scram follow events where we don't 23 have gravity drop and motor drive-in, those events are 24 categorized as a beyond-design-basis event per the LMP 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
77 currently. So they will be on our list of assessed 1
events in our LBE list.
2 MR. WILLIAMS: Thanks, Emily.
3 All right. I'll turn this over to you, 4
George.
5 MR. WILSON: My name is George Wilson.
6 I'm going to talk about what I call the interface or 7
the separation between the Energy Island and Nuclear 8
Island, the potential regulations that wouldn't fully 9
apply to our design.
10 The first thing we have to look at is the 11 NRC's definition in 10 CFR 50.2 of what safety-related 12 means. And then we look at what the NEI 18-04 13 difference in safety-related, their definition.
14 The NEI's is actually based on function 15 and frequency. The NRC's is to do with boundary and 16 has three criteria. Right now we need to either show 17 how we're going to meet the intent of 50.2 or take an 18 exemption of 50.2 and use the classification and the 19 definition and NEI 18-04 for our definition of safety-20 related.
21 I'll focus on the bottom two first. For 22 10 CFR 55, licensed operator reaction, if you look 23 into the guidelines and the definitions in 10 CFR 55, 24 this is one of the actions. We require an operator to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
78 have a license.
1 The scope of 55.2 says any individual who 2
manipulates the controls of any utilization facility 3
licensed under 50.52 and 54 of this chapter. The key 4
word there is control 5
When you go into the definitions in 10 CFR 6
50.54, the definition is controls when used with 7
respect to a nuclear reactor means an apparatus and 8
mechanism, the manipulation of which directly affects 9
the reactivity or power level of the reactor based on 10 the fact of the inertia that you can operate the 11 turban.
12 It has to go through the salt tanks and 13 then it has to go through the intermediate heat 14 transfer system. Finally, it gets to the primary heat 15 transfer system. The time lapse that it takes, there 16 is no direct reaction between operating the turbine 17 and the impact of the reactor.
18 It can be minutes or even hours before you 19 would see an impact back onto the reactor power based 20 on where you were at. So with that, it is our 21 intention to allow the turbine generator to be 22 operated by the grid operator just like they would in 23 a fossil fuel plant.
24 MEMBER MARCH-LEUBA: When you say grid 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
79 operator, do you mean somebody located in Atlanta?
1 MR. WILSON: Well, it would be someone 2
located in the grid operations of --
3 MEMBER MARCH-LEUBA: Remotely?
4 MR. WILSON: Remotely, right. It would 5
just be operated remotely. Our turbine will be 6
designed with a different ramp rate. Our plant can 7
truly load follow because there is no -- you operate 8
the turbine and reactor at a different power level.
9 So it is our intentions with our design to 10 allow our turbine to be operated remotely. There will 11 be constant communication with our control room and 12 our operators, but it would be the intention to allow 13 our turbine to be operated.
14 MEMBER MARCH-LEUBA: And of course, this 15 is a plant that will be doing the safety analysis 16 because all you do is get bored of the computer with 17 numbers. You could consider cybersecurity, attacks, 18 and all this kind of stuff -- you have to make sure 19 that the Energy Island truly does not feed back into 20 the nuclear?
21 MR. WILSON: Right. We have to have air 22 gaps. We will meet the NRC's requirement. NEI will 23 be doing the cybersecurity. We'll also have to meet 24 the requirements of the CIP standards because there is 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
80 a bright line between when FERC standards roll over 1
and it's the first isolation point after the turbine.
2 So we'll have to meet all the requirements 3
for cybersecurity and physical security. We've had to 4
look at allowing to reach out to the grid operator to 5
do the turbine. It will be something new for the NRC.
6 We've already bridged that with --
7 MEMBER MARCH-LEUBA: You're completely 8
opening the firewall to the grid operator?
9 MR. WILSON: To a certain extent. I'm not 10 going to go into that.
11 MEMBER BROWN: To a lesser extent unless 12 you open the LAN.
13 MEMBER BALLINGER: This is Ron Ballinger.
14 When you say control power remotely, will you be 15 allowing people to remote control other 16 characteristics like reactor power? Can you do that?
17 MR. WILSON: I just know right now we 18 would allow the -- I don't know about decay bars. Is 19 that what you're talking about, reactor power?
20 MEMBER BALLINGER: Yes.
21 MR. WILSON: We're still working with 22 PacifiCorps on what we're going to do, but there would 23 be no issue with them changing. You're just changing 24 the output of your turbine that you're putting into 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
81 the grid. If I'm putting a reactive load out, I would 1
have to maintain reliability.
2 We're still working those details out with 3
who would be our grid operator of PacifiCorp. That 4
would be our intention to allow them to. There will 5
be direct communications all the time, but that's 6
something that the industry is actually very 7
interested in.
8 MEMBER HALNON: So in the spirit of 9
helping move along, this has been done for 50 years.
10 The case is that they're saying it doesn't affect the 11 reactor.
12 If it doesn't affect the reactor and it 13 doesn't affect reactor safety, then what the grid 14 operator does is independent of all that. The certain 15 extent is within the limits we've already talked 16 about.
17 MEMBER MARCH-LEUBA: The problem, Greg, is 18 the US is a juicy target for the bad guys. If a 19 hacker in North Korea gets control of your Energy 20 Island, it's not a safety concern, but you'd make it 21 to CNN. And you will have to go testify in front of 22 Congress.
23 MEMBER HALNON: I think we can argue that 24 point as well. I don't think it's that juicy of a 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
82 target, but go on.
1 MR. SCHULTZ: Steve Schultz, just a 2
question. I understand the turbine operation issue 3
associated with operator licensing. The other 4
elements associated with the Energy Island, are those 5
functions for the tanks and so forth performed by a 6
licensed operator?
7 MR. WILSON: Right now we're still 8
developing our reactivity manipulations control 9
program. If you look at the NRC's conditions, it said 10 we didn't look at 54(j). We will have definitions.
11 We'll have that just like any other reactor.
12 You have to have a
reactivity 13 manipulations control program and start looking at the 14 indirect impacts and what would have to be controlled 15 by a licensed operator or overseen by the operator.
16 So we're still fully evaluating that.
17 But right now, if there would be, it would 18 be some of the stuff with the salt tanks and nothing 19 with the rest of the plant on the Energy Island side.
20 We're still looking at that. We haven't fully 21 developed that. That's one of the conditions the NRC 22 has put in our top drawer.
23 MEMBER HALNON: Understood. Thank you.
24 MR. WILSON: When we looked at 10 CFR 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
83 Appendix B, Appendix B states that this appendix 1
applies to all activities affecting the safety-related 2
functions of those structure systems and components.
3 During our classifications of the way that 4
we do the SSCs, based on when we do the licensing 5
basis events, currently there is no safety-related or 6
non-safety related with special treatment systems, 7
structures, or components located on the Energy 8
Island.
9 Therefore, on the classification -- you 10 heard the NRC staff; they'll talk about it a little 11 bit more -- their Appendix B would not apply to 12 anything on the Energy Island. The other two 13 regulations are kind of lumped together.
14 One of them would be a limited work 15 authorization of 10 CFR 50.10 and 10 CFR 50.65.
16 Requirements for monitoring effectiveness of the 17 maintenance at power plants, known as the maintenance 18 rule. 10 CFR 50.10 and 50.65 have the same language 19 in there. So 50.10 actually borrows the maintenance 20 rule language for some of the criteria.
21 When we looked at the maintenance rule 22 language specifically, we focused on (b)(2). It says 23 non-safety related structures, systems, or components.
24 It you look at item number 3, it says whose failure 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
84 could cause a reactor scram or actuation of a safety-1 related system.
2 To get additional clarification for that, 3
the NRC's Reg Guide 1160, which actually references 4
the NUMARC 93-01 standard -- and if you go into the 5
NUMARC 93-01 standard, item number 3, which is more 6
clarity to the regulations, states
- systems, 7
structures, and components identified in the 8
licensee's analysis whose failure would cause a 9
reactor scram or actuation of a safety-related system.
10 Based on that clarification, the salt system could 11 cause a reactor scram if a runback did not happen.
12 So we said that it meets that criteria of 13 the maintenance rule. It is our intention based on 14 using the LMP process to go after an exemption of this 15 based on our risk-informed performance-based approach 16 because, as I stated earlier, there's no safety-17 related or non-safety related with special treatment 18 systems in the Energy Island.
19 So really, the intent of the maintenance 20 rule was to keep those systems robust so that you made 21 sure you can do your safety system. So it is our 22 intention to go after an exemption of 10 CFR 50.65 23 just for that criteria and have those systems, 24 structures, and components in the Energy Island of the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
85 maintenance rule.
1 That's all I have. If there's no 2
questions, thank you guys for your time. We greatly 3
appreciate your time. We're here if you have any 4
other questions.
5 MEMBER MARCH-LEUBA: Out of curiosity, 6
could you tell us something of your schedule? What 7
are your plans?
8 MR. WILSON: The plan is we'll be 9
submitting our construction permit application in 10 March of 2024 for the NRC to review.
11 MEMBER MARCH-LEUBA: Your vision is to be 12 operating the plant when?
13 MR. WILSON: We'll start preconstruction 14 activities the first quarter of '25. Full operations 15
-- Nick, you can help me here -- I think it's 2030.
16 MEMBER MARCH-LEUBA: Thanks.
17 CHAIR ROBERTS: It's Tom Roberts. It's 18 now 10:05. We're about 25 minutes behind schedule.
19 To help that along, I figure we'd take about a ten-20 minute break. Looking around, I think there's 21 agreement to do that.
22 I think we have enough time towards the 23 end of the schedule here to make up the time. We'll 24 reconvene at about 10:15 this morning. We'll go with 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
86 the NRC staff and then proceed from there.
1 (Whereupon, the above-entitled matter went 2
off the record at 10:06 a.m. and resumed at 10:16 3
a.m.)
4 CHAIR ROBERTS: It is now 10:15 and we're 5
coming back into session. We now have the NRC staff 6
presentation. Candace de Messieres will start the 7
presentation for the staff.
8 MS. DE MESSIERES: Thank you, Chairman 9
Rempe and Member Roberts, for the opportunity to 10 present to the committee today. I am Candace de 11 Messieres, Chief of Advanced Reactor Technical Branch 12 2 in the Division of Advanced Reactors and Non-Power 13 Production and Utilization Facilities, or DANU, in the 14 Office of Nuclear Reactor Regulation.
15 During this meeting, the NRC staff will 16 provide you with a summary of our review of 17 TerraPower's topical report titled Regulatory 18 Management of NATRiUM Nuclear Island and Energy Island 19 Design Interfaces.
20 As we've been discussing, this topical 21 report pertains to the decoupling strategy to ensure 22 independence of operation between nuclear and Energy 23 Island systems for the NATRiUM design.
24 The topical report contains TerraPower's 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
87 evaluation for regulations and requests NRC approval 1
of the topical report such that the NATRiUM reactor 2
licensees can utilize the regulatory evaluation via 3
reference and licensing submittals.
4 I'll emphasize that this review is part of 5
ongoing pre-application engagement with TerraPower.
6 Our review conclusions rely on key preliminary design 7
and analysis aspects and assumptions.
8 These aspects and assumptions, which 9
include implementation of key design features and 10 assignment of SSC safety classifications, will be 11 confirmed as part of future licensing reviews and are 12 reflected in our topical report safety evaluation in 13 the form of limitations and conditions.
14 I will now turn it over to the NATRiUM 15 Project Management and Technical Leads, Mallecia 16 Sutton, Senior Project Manager, and Reed Anzalone, 17 Senior Nuclear Engineer, as well as Jesse Seymour, 18 Senior Reactor Engineer Examiner, to present details 19 of our review.
20 Thank you again for the opportunity to 21 present to the committee. We look forward to your 22 observations and feedback.
23 MS. SUTTON: Good morning. I'm Mallecia 24 Sutton. I'm glad to be here with you guys. Let me go 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
88 to the next slide, please.
1 I'll provide a review of the time line of 2
this topical report. We had a pre-engagement 3
application public meeting on November 17th of 2021 to 4
discuss the potential of submittal. The initial 5
submittal was a white paper titled Energy Island 6
Decoupling Strategy, which was submitted on February 7
4th.
8 At the staff review, we had another 9
discussion with TerraPower where they voluntarily 10 withdrew the submittal because we didn't have 11 sufficient information to conduct a review.
12 After further discussion, TerraPower 13 decided to submit its topical report, why we're here 14 today, titled Regulatory Management at NATRiUM Nuclear 15 Island on October 4th of 2022. Staff accepted the 16 topical report on November 16th.
17 We conducted an audit to understand the 18 transient analysis discussed in topical report to 19 demonstrate compliance with 10 CFR 50.54(j). The 20 staff will discuss more detail. The audit ran from 21 January 23, 2023 to March 10, 2023. Then staff 22 finalized the draft safety evaluation report, which 23 was issued on August 10, 2023.
24 With that, I'll turn it over to Reed to go 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
89 over the staff's evaluation of the topical report.
1 Thank you.
2 MR. ANZALONE: Thanks, Mallecia. I think 3
I can tell the microphone is working, which is always 4
a concern for me.
5 I think TerraPower did a pretty good job 6
of going over the purpose of the topical report. I'm 7
not going to talk about that anymore. I'll just focus 8
on our strategy for the review.
9 What we wanted to do in this review, given 10 where we are in the design and licensing design 11 process with TerraPower, what we wanted to focus on 12 was those key aspects of the NATRiUM design and 13 analysis presented in the topical report, and kind of 14 use that as the context for the regulatory evaluations 15 that they were doing. And then propose appropriate 16 limitations and conditions that would be necessary for 17 those evaluations to be acceptable.
18 And really, that's kind of the structure 19 of this presentation too. We're going to talk about 20 the key aspects of the design and analysis. We're 21 going to look at the regulatory evaluations, and then 22 we're going to talk about the limitations and 23 conditions.
24 Next slide. I say basically the same 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
90 thing on this slide. Next slide, please.
1 So I also have a little design overview 2
that I put together that I think goes along with what 3
TerraPower did. We can walk through this pretty 4
quickly.
5 These figures are taken from the topical 6
report. There's the primary heat transport system.
7 There's the intermediate loop going between the 8
intermediate heat exchanger and the sodium-salt heat 9
exchanger.
10 There's the thermal salt storage system 11 with the hot and cold salt tanks. And the separation 12 between the Nuclear Island and Energy Island is those 13 isolation valves there on the thermal salt storage 14 system.
15 Also on the Energy Island there's the 16 steam generating system. Those are the same diagrams 17 that TerraPower presented earlier.
18 Keep going.
19 So on the Nuclear Island, we've got these 20 safety systems, the reactor air cooling system, and 21 the intermediate air cooling system. The one thing I 22 wanted to talk a little bit more about on this slide 23 was the audit, which TerraPower touched on a little 24 bit, what they shared with us. I wanted to just 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
91 mention the key audit findings.
1 We looked at the analysis that they 2
performed concerning the Energy Island/Nuclear Island 3
interface and the ability of the Nuclear Island to 4
respond to transients on its own. Those Energy Island 5
events -- and TerraPower mentioned this -- that have 6
the greatest possibility to affect the Nuclear Island 7
are the ones that occur physically closest to the 8
Nuclear Island.
9 Events that occur further out from that 10 interface can really all still be boiled down to 11 changes at the Nuclear Island/Energy Island interface.
12 The question is just how long does it take for those 13 changes to propagate through.
14 Even then, once you have those changes 15 that you see at the Nuclear Island/Energy Island 16 interface, how long does it take those to propagate 17 through to where they have an effect on the core?
18 TerraPower talked a bit about the thermal 19 inertia of the various systems. We see that those are 20 really significant towards making the case for Energy 21 Island/Nuclear Island independence.
22 The design of the primary heat transport 23 system, the fact that they're using a pool-type SFR, 24 the intermediate heat transport system and how big it 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
92 is. And then the really big thing is the thermal salt 1
storage
- system, which pretty much effectively 2
insulates changes in turbine power from affecting 3
reactor power, as we've discussed.
4 Next slide.
5 MR. SCHULTZ: Reed, before you go on, this 6
is Steve Schultz.
7 MR. ANZALONE: Sure.
8 MR. SCHULTZ: I meant to ask TerraPower 9
about this. You talked about the time frames that are 10 available for the interaction between the Energy 11 Island and the Nuclear Island qualitatively. Can you 12 quantify that a bit, the power and so forth?
13 MR. ANZALONE: It really depends on the 14 specific transient, what's going on, and what system 15 you're talking about. But it is minutes to hours, not 16 seconds. I think that's pretty much the only level I 17 can -- it really depends on the particular --
18 MR. SCHULTZ: That's fine. I wanted to 19 get the minutes and the powers on the record. Thank 20 you.
21 MR. ANZALONE: Okay. I think George 22 mentioned that during the last little bit of --
23 MR. SCHULTZ: Thank you.
24 MR. ANZALONE: So I'm going to touch on 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
93 the safety classification using NEI 18-04, which is 1
the risk-informed, performance-based technology 2
inclusive guidance for non-light-water reactor 3
licensing basis development. That's a mouthful so I'm 4
just going to say NEI 18-04 LMP from now on.
5 We endorsed that in Reg Guide 1.233.
6 TerraPower is following those approaches as endorsed 7
in the Reg Guide.
8 It's a risk-informed, performance-based 9
safety classification approach that's laid out in NEI 10 18-04, which is highly integrated with other aspects 11 of the process including the selection and analysis of 12 licensing basis events and evaluation of adequacy. I 13 think TerraPower later in the presentation showed some 14 of those pieces all together.
15 It's a slightly different definition for 16 safety-related SSCs than in 50.2, which George touched 17 on. The 50.2 definition talks about safety-related 18 SSCs should be those needed to ensure the integrity of 19 the reactor coolant pressure boundary, the capability 20 to shut down the reactor and maintain it in a safe 21 shutdown condition, or the ability to prevent or 22 mitigate the consequences of accidents which could 23 result in off-site releases comparable to the 50.34 24 limits.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
94 We think that conceivably you could use 1
the LMP process to demonstrate compliance with that 2
50.2 definition of safety-related, but you may or may 3
not. So you might need to take an exemption from 4
50.2. I think TerraPower is considering that as well.
5 Go to the next slide, please, Candace.
6 CHAIR ROBERTS: Reed, Tom Roberts. I'm 7
just trying to understand some examples of what might 8
not meet the definition of 50.2, if it were shown to 9
be safety-related per LMP.
10 MR. ANZALONE: I think there's a question 11 of whether what TerraPower has in their reactor design 12 constitutes a reactor coolant pressure boundary, 13 quote/unquote, because it's operating at atmospheric 14 pressure.
15 They have made a distinction historically 16 between reactor coolant boundary versus reactor 17 coolant pressure boundary. Other more exotic designs 18 might deviate a little bit even further away from 19 those definitions in 50.2.
20 So NEI 18-04 and our Reg Guide kind of 21 leaves open the possibility that you might need an 22 exemption from 50.2. Does that answer the question?
23 CHAIR ROBERTS: I think so. Is that the 24 case here? It seems like integrity of the coolant 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
95 boundary is going to be required regardless of what 1
you call it.
2 MR. ANZALONE: Yes. It's just a matter of 3
wording. I think they would propose an alternate 4
definition. I believe there was a public meeting we 5
had with them some time last year where they talked 6
about changing that to just say reactor coolant 7
boundary or primary coolant boundary instead of 8
reactor coolant pressure boundary.
9 CHAIR ROBERTS: It gets into more 10 semantics than technical? That's what I'm trying to 11 understand.
12 MR. ANZALONE: Yes. I would agree with 13 that.
14 CHAIR ROBERTS: Okay. Thank you.
15 MR. ANZALONE: So the NEI 18-04 process 16 uses this definition for the different safety 17 classifications that are available. There's the 18 safety-related SSCs and those are the SSCs selected 19 for the required safety functions to mitigate design-20 basis events within the frequency consequence target 21 curve. I have a slide coming up where I'm going to 22 explain what that actually means.
23 And SSCs selected for required safety 24 functions to prevent high consequence beyond design-25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
96 basis events from entering the design-basis event 1
region beyond the frequency consequence target. I'll 2
talk about those more when we get to the next slide.
3 There's also this concept of non-safety 4
related with special treatment, which is roughly 5
analogous to Part 50. Those are the non-safety 6
related SSCs that are performing risk significant 7
functions or needed for defense-in-depth.
8 I think that conceptually you can think 9
about you might have multiple SSCs that can do a 10 safety function. You would have one you would 11 designate as safety-related and then you would have 12 another that you would designate potentially as non-13 safety related with special treatment.
14 And then the final category is non-safety 15 related with no special treatment, which as TerraPower 16 has discussed, they're trying to get all those Energy 17 Island SSCs to be in that final category.
18 Next slide, please, Candace.
19 Here's the frequency consequence target 20 curve from NEI 18-04. I'm just going to use this to 21 try to help explain those safety-related SSCs.
22 If you can advance it a little bit, that's 23 the design-basis event region, which is those events 24 that have a frequency between 1E minus 4 and 1E minus 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
97
- 2. The high consequence beyond design-basis events 1
are those in the beyond-design basis event region.
2 So that's between five times ten to the 3
minus seventh and ten to the minus fourth. Those are 4
beyond the 50.34 dose limit. The safety-related SSCs 5
are used to keep the DBEs within the frequency 6
consequence target. The high-consequence BDDE is 7
within the frequency consequence target.
8 Also -- if you can advance it one more 9
time, Candace -- only the safety-related SSCs are 10 available to keep design-basis accidents below the 10 11 CFR 50.34 dose limit.
12 Those design-basis accidents are DBE 13 events that have been stylized to use very 14 conservative assumptions. There's a deterministic 15 analysis that's done to show that they stay below the 16 50.34 limit using only safety-related SSCs.
17 MEMBER MARTIN: This is Bob Martin. Is 18 their power showing preliminary results for dose 19 consequences --
20 MR. ANZALONE: Yes.
21 MEMBER MARTIN: -- and their methodology?
22 Is there a slide, maybe somewhere else because it's 23 not here, of how they compare to the curve?
24 MR. ANZALONE: There are some results 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
98 from, I want to say, earlier this year. Those were at 1
the time considered proprietary.
2 MEMBER MARTIN: We're okay seeing that, 3
right?
4 MR. ANZALONE: Yes since this is a public 5
meeting. Yes, everything was inside the target curve.
6 MEMBER MARTIN: They submitted a topical 7
on those consequences and methodology?
8 MR. ANZALONE: They will be submitting a 9
topical and on the deterministic safety analysis. The 10 safety classification process was one of the key 11 things that we were considering in our review of the 12 topical report in addition to the design.
13 So now I'll talk a little bit about the 14 regulations that were covered in the topical. I think 15 George actually did a great job overviewing these 16 during TerraPower's presentation.
17 They looked at 50.10 and 50.65, which are 18 the LWA rule and the maintenance rule which, as he 19 said, have identical requirements for some of them.
20 They looked at Appendix B and Part 55.
21 Next slide.
22 The LWA rule provides a requirement that 23 no person may begin the construction of a production 24 or utilization facility on a site on which the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
99 facility is to be operated until they've been either 1
issued a construction permit or a limited work 2
authorization.
3 50.10(a)(1) provides the scoping criteria 4
that defined what constitutes construction in the 5
context of the rule. Those scoping criteria were 6
chosen to encompass those SSCs that have a reasonable 7
nexus to radiological health and safety or common 8
defense and security.
9 If you go to the next slide, Candace.
10 Criteria 2, 3, and 4 were chosen based on 11 the language in the maintenance rule, which had 12 already been around for some time at this point.
13 Basically, when the Commission was promulgating the 14 LWA rule, there was a desire to try to use agreed-upon 15 definitions for what had a reasonable nexus to health 16 and safety.
17 They just basically lifted those criteria 18 from the maintenance rule because there was guidance 19 and they had been used for some time. Then also, 20 criteria 1 is safety-related SSCs.
21 And then there are several additional 22 criteria. Those necessary to comply with Part 73, 23 which is the security regulations, those needed to 24 comply with 50.48 and criteria 3 of the general design 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
100 criteria, which are fire protection regulations and 1
those needed for on-site emergency facilities.
2 If you could go to the next slide?
3 MR. MARCH-LEUBA: Not allowing testing?
4 You have testing at the end of the first paragraph.
5 MR. ANZALONE: I have to say I don't 6
actually know off the top of my head.
7 MR. MARCH-LEUBA: I think if they come and 8
ask you that you would tell them, yes, go ahead and 9
test all you want. Okay.
10 MR. ANZALONE: So I'm going to walk 11 through all the criteria in 50.10(a)(1). First I'll 12 talk about TerraPower's evaluation and then I'll talk 13 about what we thought about that evaluation.
14 So criteria 1 they said wasn't applicable 15 because those Energy Island SSCs are non-safety 16 related with no special treatment. We said that was 17 reasonable.
18 It's consistent with the NEI 18-04 safety 19 classification definition, but we did have a 20 limitation regarding the definition of safety-related.
21 I've already talked about how there's a distinction 22 between the 50.2 definition and the NEI 18-04 23 definition.
24 Criteria 1 here actually specifically 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
101 refers back to 50.2. Rather than saying safety-1 related, it says safety-related SSCs as defined in 10 2
CFR 50.2.
3 So if it just said safety-related, it 4
wouldn't necessarily be an issue. But if they're 5
getting an exemption from 50.2, they would also need 6
to get an exemption here. And that's what the 7
limitation tries to make clear.
8 Criteria 2 TerraPower determined wasn't 9
applicable because Energy Island SSCs aren't used to 10 mitigate accidents or transients or used in the EOPs, 11 the emergency operating procedures. We thought that 12 was consistent with the plant design.
13 We wouldn't expect non-safety related SSCs 14 to participate in mitigation or prevention of 15 accidents or transients, but we haven't reviewed 16 TerraPower's emergency operating procedures. They're 17 still under development. So we added a limitation and 18 condition on the topical report to address that.
19 Criteria 3 isn't applicable because the 20 NSD SSCs wouldn't be capable of preventing safety-21 related SSCs from fulfilling their safety functions.
22 We thought this was consistent with the NEI 18-04 23 safety classification definition. And I'll also note 24 I think I have a slide that talks a little bit more 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
102 about this later.
1 There was a comment or a staff position in 2
the Reg Guide endorsing NEI 18-04 that says basically, 3
if an SSC provides a central support to a higher 4
classified SSC, so if you had an SSC providing support 5
to a safety-related or non-safety related with special 6
treatment SSC, we would expect that support in SSC to 7
be classified the same as the higher classification 8
SSC.
9 And finally, on this slide criteria 4, and 10 George talked about this, they determined that it was 11 applicable because the failure of an Energy Island SSC 12 could eventually cause a reactor trip and they planned 13 to seek an exemption. And that they would use the 14 same exemption basis for 50.10(a)(1)(4) and 15 50.65(b)(2)(3) because those are the same language.
16 We agreed with TerraPower's determination 17 that the criteria was applicable. We thought it was 18 reasonable to use the same exemption basis for the two 19 regulations that have the same language, but we didn't 20 take a position on the prospective exemption. We'll 21 review that when we get it.
22 Next slide.
23 Criteria 5
TerraPower said wasn't 24 applicable because there wouldn't be any physical 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
103 security program SSCs on the Energy Island. And that 1
if they had any SSCs that were identified as critical 2
digital assets for the cybersecurity program, they 3
wouldn't be installed on the Energy Island prior to 4
the construction permit.
5 We felt like that was consistent with the 6
design, but we kind of expect that that would be 7
constrained in scope to the Nuclear Island. We didn't 8
have a lot of detail on the security program. We're 9
going to have to look at those further when we have 10 those details.
11 Criteria 6 they judged to be non-12 applicable because fires on Energy Island would not 13 prevent the ability to maintain and achieve shutdown, 14 which is really the focus of 50.48. We thought that 15 that was an adequate evaluation because those Energy 16 Island SSCs are non-safety related with no special 17 treatment, as TerraPower talked about quite a bit 18 today, and can be achieved and maintained solely using 19 Nuclear Island systems.
20 And then finally, criterion 8 they 21 determined was not applicable because the on-site 22 emergency facilities would not be located on the 23 Energy Island. We felt like that was consistent with 24 the plant design and could be a design goal, but we 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
104 hadn't seen that flushed out yet to the point where we 1
could say definitively yes. The on-site emergency 2
facilities are not on the Energy Island. So we had a 3
limitation condition there.
4 Next slide.
5 MEMBER HALNON: So the end result of all 6
of this was this evaluation in combination with the 7
limits and precautions, limits and conditions, and 8
their exemptions? They can build Energy Island 9
without a limited work authorization?
10 MR. ANZALONE: If it appears it's going in 11 that direction.
12 MEMBER HALNON: Okay. So this is a hurdle 13 that they jumped over, and it looks like there's a 14 clear road ahead but there's still some --
15 MR. ANZALONE: Yes. I would agree with 16 that.
17 So I'll talk a little bit about the 18 maintenance rule but really, fundamentally the 19 evaluation was basically the same as for 50.10. The 20 maintenance rule requires licensees to have a program 21 that monitors the performance or condition of certain 22 SSCs or demonstrates that they'll be able to perform 23 their intended functions through appropriate 24 preventative maintenance.
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105 The scope of the SSCs are basically the 1
same as the several regulations that we already talked 2
about in 50.10. 50.65(b)(1) is similar to but not 3
identical to 50.10(a)(1)(i) in that it doesn't say 4
safety-related SSCs as defined in 50.2. It says 5
safety-related SSCs to include all of the stuff that's 6
in the definition in 50.2, so it's a little bit 7
different there, but then the other criteria in 50.65 8
are the same as the ones in 50.10.
9 Next slide.
10 So TerraPower didn't evaluate 50.65(b)(1),
11 which is the note about safety-related, so we didn't 12 disposition that in our safety evaluation. The other 13 criteria we evaluated the same as in our evaluation 14 under 50.10.
15 Next slide.
16 Appendix B provides quality assurance 17 requirements for the
- design, manufacture, and 18 construction of certain SCCs, and it applies to all 19 activity is affecting the safety-related functions of 20 SSCs that prevent or mitigate the consequences of 21 postulated accidents that could cause undue risk for 22 the health and safety of the public.
23 Next slide.
24 So TerraPower asserted that all the Energy 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
106 Island SSCs will be non-safety related with no special 1
treatment, and that SSCs classified as non-safety 2
related with no special treatment under that NEI 18-04 3
process wouldn't be capable of affecting the safety-4 related function of the SSCs used for prevention or 5
mitigation.
6 We considered the role that we would 7
expect non-safety related SSCs to play, and determined 8
that the evaluation was acceptable. That's the staff 9
position that I mentioned earlier, that support SSCs 10 should be classified at the higher level of the SSCs 11 that they support.
12 Now I'm going to turn it over to Jesse --
13 MEMBER MARCH-LEUBA: Hold on.
14 MR. ANZALONE: Sure.
15 MEMBER MARCH-LEUBA: Let me just make a 16 comment. This is not a criticism. Appendix B is 17 good. Appendix B is also painful and expensive to be 18 brought in.
19 From a public presentation point of view, 20 they don't need to do any QA on the Energy Island.
21 I'm sure TerraPower is going to do some ISS standard 22 or something like that.
23 So from a public presentation point of 24 view, we should say that the QA that they're planning 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
107 to do is sufficient and doesn't need to be expanded to 1
the Appendix B's standards. I'm just suggesting that 2
because I'm sure you're going to use QA. It's an 3
expensive plant.
4 MR. ANZALONE: Point taken. Thank you.
5 MEMBER HALNON: The QA is going to be 6
essentially -- it's required by the construction 7
codes, right?
8 MR. ANZALONE: Which is not nothing.
9 MEMBER HALNON: No. You've got all kinds 10 of steps on there.
11 MR. ANZALONE: All right. Now Jesse is 12 going to talk a little bit about Part 55.
13 MR. SEYMOUR: Thank you, Reed.
14 My name is Jesse Seymour. I'm an operator 15 licensing examiner and technical reviewer at NRR. I 16 reviewed the Part 55 related portion of the topical 17 report.
18 In the topical
- report, TerraPower 19 describes that the NATRiUM design removes direct 20 interaction between the reactor and the turbine 21 generator, which results in operation of the turbine 22 generator not constituting an apparatus or mechanism.
23 This manipulation directly affects the reactivity or 24 power level of the reactor.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
108 TerraPower also states in the topical 1
report that NATRiUM design would allow for a non-2 licensed operator based upon that to operate the 3
turbine generator. From an operator licensing 4
perspective, this is much different than the current 5
large light-water reactor practice in which turbine 6
generator operations have historically been considered 7
to be control manipulations, and therefore restricted 8
to being only performed by licensed operators.
9 In evaluating TerraPower's position, a key 10 consideration is TerraPower's description of the 11 NATRiUM thermal storage system as providing a 12 significant thermal energy storage capacity that can 13 be used to support electrical generation such that the 14 reactor power wouldn't be directly correlated to 15 turbine manipulations.
16 MEMBER HALNON: Jesse, did you look at 17 this from just the turbine generator set or for the 18 whole Energy Island perspective?
19 MR. SEYMOUR: I'll address the Energy 20 Island aspect a little further into this. The primary 21 consideration was who could operate the turbine. So 22 again, when you're looking at the Energy Island, 23 obviously there's other things that could potentially 24 be seen coming off the system, drawing salt energy.
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109 MR. HALNON: Levels of the salt tanks was 1
what I was -- it seems like the closest connection to 2
effects on the Nuclear Island. That's what I was 3
curious about, whether or not we're talking about an 4
exemption for the entire Energy Island or just what 5
you have to run the turbine with.
6 MR. SEYMOUR: So the focus of topical 7
evaluation is going to be on the turbine generator 8
operation itself and whether the turbine constitutes 9
a control. When we get to the broader discussion of 10 the Energy Island, that's covered more so by the 11 50.54(j) discussion I'll be going through later on.
12 MR. HALNON: Okay.
13 MR. SEYMOUR: One thing I do want to throw 14 in there is this is part of the reason that we wanted 15 to judge the exemptions on their own merits when those 16 come in. Those will more, we would expect, very 17 clearly define the scope of what would be exempt and 18 what wouldn't.
19 We evaluated these considerations within 20 the context of the regulations of 10 CFR Parts 50 and 21 55, the associated regulatory history, and the 22 relevant statutory requirements. As I'll discuss in 23 detail in the next slide, the word direct is used in 24 the definition of control is central to understanding 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
110 the meaning of key regulations involved here and 1
evaluating the assessment of the topical report.
2 Next slide, please.
3 The Atomic Energy Act defines operators 4
under Section 11 as being individuals who manipulate 5
the controls of utilization facilities. The Atomic 6
Energy Act also mandates under Section 107 that 7
individuals who operate utilization facility controls 8
must be licensed by the NRC.
9 Thus, there is a statutory driver behind 10 why only licensed operators will operate the controls 11 of the facility. Very importantly, though, the Atomic 12 Energy Act does not define what those controls 13 actually consist of, which leaves that definition to 14 instead be made by the NRC via regulation.
15 From the inception of operator licenses 16 back in 1956, manipulation of the controls of the 17 utilization facility has been restricted to licensed 18 operators under the Regulation 50.54(i). That 19 specific regulation is very closely linked to the 20 Atomic Energy Act provisions that I discussed.
21 It's worth noting that the original 1956 22 definition of controls was much broader than the 23 modern version and formally encompassed mechanisms 24 which by manipulation or failure to manipulate singly 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
111 or in combination could result in the release of 1
atomic energy or reactor materials in amounts 2
determined by the Commission to be sufficient to cause 3
danger to the health and safety of the public. So 4
again a very, very broad definition in its original 5
form.
6 In 1963, the Atomic Energy Commission 7
narrowed that definition significantly on the basis 8
that a regularly narrow interpretation of what was 9
truly controlled would be more consistent with the 10 Commission's original intent.
11 An amended definition of controls remains 12 unchanged in its present day and is limited to the 13 scope of apparatus and mechanisms, the manipulation of 14 which directly affects the reactivity or power level 15 of the reactor.
16 Separately, 50.54(j) was also introduced 17 in 1963, which also addresses the manipulation of 18 apparatus and mechanisms other than the controls, the 19 operation of which may affect the reactivity or power 20 level of a reactor and states that those shall be 21 manipulated only with the knowledge and consent of a 22 licensed operator present at the controls.
23 Notably, those types of operations are 24 permitted to be conducted by individuals other than 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
112 licensed operators provided that the provisions or 1
consent and oversight are still met.
2 The key takeaway here is that the 3
regulations recognize the distinctions between an 4
apparatus or mechanism, whose manipulation directly 5
affects the reactivity or power level of the reactor, 6
and those that are not direct in nature, with separate 7
requirements governing each of those.
8 As mentioned earlier, the word direct and 9
the definition of controls is the key here. The 10 implication of the use of the word direct was that 11 controls can be interpreted to mean apparatus and 12 mechanisms that when manipulated affect reactor power 13 level reactivity without also needing something 14 intermediate to make that happen.
15 Manipulations of that type fall under the 16 scope of 50.54(i) and their performance is going to be 17 restricted to licensed operators and senior operators.
18 Again, there's a very direct tie back to the Atomic 19 Energy Act on that.
20 Thus the presence or absence of a 21 significant intermediary between any given 22 manipulation and the reactivity or power level effects 23 on the reactor is the key factor that we as a staff in 24 our judgement identified as being the essential 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
113 determinant of whether given operations fall under the 1
scope of 50.54(i).
2 Based upon that perspective, we evaluated 3
the implications of NATRiUM's described design and 4
determined that the thermal storage system would act 5
as a significant intermediary between manipulations 6
involving Energy Island steam loads and reactivity 7
effects on the reactor.
8 This led to our conclusion in the safety 9
evaluation. Manipulations of NATRiUM apparatus and 10 mechanisms that affect Energy Island steam loads do 11 not directly affect the reactivity or power level of 12 the reactor, and therefore do not fall under the scope 13 of 50.54(i).
14 The topical report does not address 15 compliance with 50.54(j) though.
This was 16 incorporated into the limitations and conditions that 17 will be discussed later in the presentation.
18 Unless there's questions, I'll go ahead 19 and turn it back over to Reed.
20 MEMBER HALNON: So you're talking about 21 the thermal storage system doesn't affect reactivity, 22 but it sounds like it could cause a reactor scram or 23 runback. How is that not affecting reactivity?
24 MR. SEYMOUR: The distinction made here is 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
114 you have a category of things that directly are 1
discussed to affect reactivity, and you have a 2
category of things that the operation of which may 3
affect reactivity.
4 The distinction is that one set of things 5
falls under (i) in 50.54(i) and the other falls under 6
(j). What we're saying here in the topical is that 7
there is very well a subset of things that could fall 8
under (j). We'll cover that in a limitation that we 9
put on there.
10 MEMBER HALNON: So that's all being dumped 11 into (j)?
12 MR. SEYMOUR: That's correct, yes. So 13 it'll still be necessary for TerraPower to show how 14 they're going to comply with (j) or to go through and 15 seek some type of an exemption.
16 I would mention, and I'll build upon this, 17 during the audit we did query TerraPower on how they 18 want to pursue compliance with (j). Again, this was 19 done in audit so it's not something that's necessarily 20 reflected in safety evaluation.
21 They did provide us with a copy of their 22 draft reactivity plan. At the point that we looked at 23 it, it was still in a very rudimentary state, being 24 flushed out. But that plan was intended to, I 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
115 believe, eventually show how they're going to comply 1
with 50.54(j) for Energy Island operations.
2 MEMBER HALNON: So you get another bite at 3
the apple to discuss how the thermal systems could 4
affect reactivity?
5 MR. SEYMOUR: That's right. Ultimately 6
the applicability is still there for 50.54(j), which 7
puts that into a regime where you either have to 8
comply or seek an exemption from it.
9 MEMBER HALNON: Okay.
10 MR. SEYMOUR: Again, there's a significant 11 difference between (i) and (j). With 50.54(i), as I 12 talked about, there's almost a straight line going 13 back to the Atomic Energy Act.
14 MEMBER HALNON: Yes. It seems like 15 there's a success route there. It's just a matter of 16 what the documentation is going to be?
17 MR. SEYMOUR: That's correct.
18 MEMBER HALNON: Okay.
19 MR. SEYMOUR: I'll turn it over to you, 20 Reed.
21 MR. ANZALONE: I think that's one of the 22 themes of what we're talking about here. There's a 23 success path. We're kind of outlining what that 24 success path looks like, but that path has to be 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
116 walked.
1 Now I'm going to talk a little bit about 2
the limitations and conditions, which kind of provide 3
the contours of that path. The first limitation is 4
about key aspects of the NATRiUM design.
5 That states that applicants referencing 6
the topical would need to use a plant design that's 7
substantially similar to what was discussed in the 8
topical and that deviations that could affect the 9
safety evaluation conclusions need to be justified 10 when the topical report is referenced.
11 I think in general in the topical report 12 process, this is one of these things that's kind of 13 assumed would happen that you need to justify the 14 applicability of the topical report to your plant when 15 you reference it. But we wanted to put this in as 16 limitations to underscore the importance of those 17 design features that enable the independence of the 18 Nuclear Island and Energy Island.
19 While those regulatory evaluations that we 20 talked about were really relatively high level, we did 21 make our determinations in the context of the NATRiUM 22 design and its capabilities. Part of the reason we're 23 doing this too and putting it specifically as a 24 limitation in the condition is that there is interest 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
117 in applying similar approaches to decouple the Nuclear 1
Island and Energy Island that's been expressed to us 2
by other industry organizations.
3 So we wanted to kind of outline, here are 4
the things that you need to happen in the design to 5
make something like this possible.
6 Next slide.
7 So limitation condition 2 talks about the 8
safety classification process. This is sort of a 9
similar theme to the first one. They use NEI 18-04 in 10 the topical report to do the safety classification.
11 We relied on that to make our 12 determinations, but also the design process is 13 iterative. NEI 18-04 identifies that it would be 14 intended to be applied iteratively as the design 15 matures. Eric mentioned this in their presentation.
16 They've done these analyses. They are 17 doing these analyses. They're going to continue to do 18 these analyses and reconfirm as the design matures 19 that the Energy Island SSCs continue to be non-safety 20 related with no special treatment for the conclusions 21 in our safety evaluation to remain applicable.
22 So limitation 3, this is the one talking 23 about the difference in the definition between 50.2 24 and NEI 18-04 for safety-related. And I think I 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
118 already covered that one. I'll move on.
1 Limitation 4, there are other definitions 2
in the regulations of construction. Part 51, which is 3
the environmental regulations, also has a definition 4
of construction that's similar or possibly identical 5
to Part
- 50.
I'm in safety licensing, not 6
environmental, so I'm not actually that familiar with 7
the environmental regulations.
8 We just wanted to make it clear that the 9
evaluation applies to the Part 50 definition of 10 construction that TerraPower evaluated. It doesn't 11 apply to any other places that construction might be 12 defined.
13 Five, and I already talked about this. We 14 haven't reviewed EOPs for NATRiUM and TerraPower 15 didn't discuss them in sufficient detail to ensure 16 they don't rely on Energy Island SSCs.
17 Six and 7, similar to 5. We're going to 18 need more information on the physical and 19 cybersecurity programs to ensure that the Energy 20 Island doesn't include SSCs that fall under the scope 21 of those programs. We think the design supports it, 22 but we didn't have enough to be able to say 23 definitively.
24 Now Jesse is going to talk about 8 and 9.
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119 MR. SEYMOUR: Thanks, Reed.
1 As mentioned earlier, the topical report 2
does not address the requirements of 50.54(j).
3 Therefore, we did not provide any safety evaluation of 4
the implications of NATRiUM's design as it relates to 5
that specific regulation.
6 Again, 50.54(j) deals with apparatus and 7
mechanisms, the operation of which may affect 8
reactivity. It does not require a licensed operator 9
to do those things, but a licensed operator at the 10 controls has to provide knowledge and consent.
11 Thus, any NATRiUM facility licensee or 12 applicant for an operating license or combined license 13 that references this topical report, in the absence of 14 receiving an exemption, must ensure that manipulation 15 of any Energy Island apparatus or mechanism which may 16 affect the reactivity or power level of the reactor is 17 only permitted with the knowledge and consent of a 18 licensed operator or senior operator.
19 Beyond that, 55.31(a)(5) requires that 20 reactivity manipulations for operative licensed 21 applicant experience requirements must involve 22 operating the controls which, as discussed earlier, 23 are associated with direct reactivity or power 24 changes.
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120 Therefore, any apparatus or mechanism 1
determined to not be a control must logically also be 2
excluded from being acceptable for applicant 3
experience credit under 55.31(a)(5). Again, this was 4
important to point out because historically we've 5
accepted those loading changes as a reactivity 6
manipulation for that type of credit.
7 So consistent with that, applicants for 8
operator or senior operator licenses at a NATRiUM 9
facility where the facility licensee references its 10 topical will not be able to rely upon manipulation of 11 apparatus and mechanisms that affect Energy Island 12 steam loads, including the turbine generator, for the 13 purposes of satisfying those operator license 14 experience requirements.
15 I'm going to turn it back over to Reed 16 again.
17 MR. ANZALONE: I'll just talk about this 18 last limitation, which is pretty simple. The topical 19 report discussed the basis for the proposed 20 exemptions. We reviewed it for information, but we're 21 not taking a perspective on the exemptions that we 22 haven't received yet in the safety evaluation.
23 MR. BLEY: Excuse me. This is Dennis 24 Bley. Could you back up one slide and go over that 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
121 last point you made? It kind of slipped past me. I 1
didn't fully understand it.
2 MR. SEYMOUR: Sure. This is Jesse. When 3
a licensed operator applicant applies for a license, 4
one of the requirements is that they have to show they 5
conducted five significant reactivity manipulations.
6 Those can either be done on an actual plant, or with 7
a few more restrictions it can be done on a simulator.
8 One of the keys is that they have to 9
utilize the controls of the facility. Historically, 10 with the existing large light-water fleet, we have 11 accepted credit for those occurring, moving the rods, 12 berating, diluting, manipulating recirculation pumps 13 on the reactor side. And then over on the secondary 14 side changing turban loading has been something that 15 we've accepted for credit before.
16 So based upon this topical report and our 17 evaluation of it, again, it creates a little bit of a 18 logical disconnect if you were going to say that the 19 turbine and its manipulation does not constitute a 20 control on the one hand, but then on the other hand 21 allow that to still be credited for those types of 22 applications.
23 Essentially, what that condition and 24 limitation is saying there is that you can't have your 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
122 cake and eat it too, for lack of a better way to put 1
it.
2 MR. BLEY: Okay. I think I get it now.
3 Thank you.
4 MR. SEYMOUR: If you could go to the next 5
slide, please?
6 So the high-level conclusions. The 7
topical report is acceptable for referencing future 8
licensing submittals subject to our limitations and 9
conditions, which we think delineate that path where 10 it would be acceptable. The plant design and Energy 11 Island's safety classification, they are integral part 12 of our evaluation.
13 With that, I will open it up to any 14 questions.
15 MEMBER HALNON: On the cybersecurity side 16 when we drew the bright line back in 2010-ish time 17 frame for operating plants, are you going to carry 18 that same scope, I guess, for lack of better terms, 19 for the NRC to be into the construction as well?
20 I assume that when Vogel was constructed, 21 the NRC looked at the compliance with the New York 22 side as well, like they do in the operating plants.
23 Is that going to carry forward in these advanced 24 reactors as well?
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123 MR. SEYMOUR: I'm not a cybersecurity 1
expert so I can only comment so much, but that is 2
basically my understanding of where things are. We've 3
talked with the cybersecurity people about this.
4 MEMBER HALNON: Okay. So obviously, 5
there's no major change in how we're going to be 6
looking at it in the future then?
7 MR. SEYMOUR: Not to my understanding, but 8
I could be proven wrong.
9 MEMBER HALNON: Okay.
10 MR. MARCH-LEUBA: My concern with the 11 cyber is this starts defining political components.
12 Nothing in the NEI is a political component.
13 Therefore, a cybersecurity plan is not required.
14 MEMBER HALNON: Well, by the NRC's 15 standard. The NERC standard would put them into a 16 more special category.
17 MR. MARCH-LEUBA: I've always said you 18 guys have to be looked for aquariums. And the EI 19 sounds to me like an aquarium. I will tell you the 20 story after. Or just Google cybersecurity attack on 21 a casino with an aquarium.
22 MS. de MESSIERES: This is Candace de 23 Messieres of the NRC staff again. I just wanted to 24 reiterate we did explicitly put that limitation and 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
124 condition in the topical safety evaluation just 1
because we do need more information in this area, so 2
more to come.
3 MR. SCHULTZ: Reed and Jesse, this is 4
Steve Schultz. Just to confirm in general, during the 5
presentations today from TerraPower, your review of 6
your overall evaluation, and the limitations and 7
conditions, things are aligned between you and 8
TerraPower, associated with their actions that they 9
see they need to take in regard to the exemption 10 requests?
11 MR. SEYMOUR: Yes, I would say so.
12 MR. SCHULTZ: And other follow-up actions 13 associated with the limitations and conditions?
14 MR. SEYMOUR: Yes.
15 MR. SCHULTZ: And with regard to the 16 exemptions, it doesn't seem as if they're high 17 hurdles, the Part 50 exemptions that TerraPower is 18 moving forward to obtain.
19 MR. SEYMOUR: I think I would agree with 20 that. Like I said, they laid out a lot of the basis 21 for the exemptions in the topical report, so we're 22 kind of aware of where they're going to go.
23 MR. SCHULTZ: So your limitations and 24 conditions are aligned with that as well?
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125 MR. SEYMOUR: Yes.
1 MR. SCHULTZ: Thank you.
2 CHAIR ROBERTS: Are there any other 3
questions from the members online?
4 MEMBER KIRCHNER: No, thank you, Tom.
5 CHAIR ROBERTS: Thanks, Walt.
6 Hearing none, I have one final question 7
for the staff. Is there anything in this topical 8
report you think was innovative or kind of ground-9 breaking or just kind of the normal process of doing 10 business with the pre-application phase?
11 MR. SEYMOUR: I would say the whole 12 concept is kind of innovative and ground-breaking, but 13 I think that's mostly just because nobody has really 14 had a technology that seemed to us to be capable of 15 doing this previously.
16 I think for a lot of the reasons that 17 Jesse and I have laid out, it's not something that you 18 could do with a large light-water reactor with the 19 current designs that are in the operating fleet. So 20 it took somebody coming up with a design that was 21 capable of doing this and then trying to put into 22 practice.
23 I think there is some ongoing things that 24 TerraPower is going to need to make sure of. I'm 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
126 confident that they are going to do that because this 1
is one of their key design principles, to maintain the 2
separation between the Energy Island and the Nuclear 3
Island.
4 But as they go through the process, 5
they're going to have to continue to try to reinforce 6
that separation to be able to make sure that these 7
things can actually be followed through as they're 8
described in the topical report. I'll leave it at 9
that.
10 MR. BLEY: This is Dennis. Could I ask a 11 question of TerraPower? Throughout this discussion, 12 you talked a lot about using the LMP. We've heard 13 some complaints from people about how arduous that is.
14 So I have two questions for you. One is, 15 can you describe a little bit how you found the use of 16 the LMP in your projects so far?
17 Two, do you have any comments on the 18 limitations and conditions the staff has placed in 19 their review? Were they surprises to you or are you 20 pretty comfortable with them?
21 MR. JOHNSON: This is Brian Johnson on the 22 line, Manager of Nuclear Safety Licensing leading up 23 the risk reliability efforts and a lot of the LMP 24 implementation.
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127 I will agree. I think the LMP is somewhat 1
arduous, but I think it's a worthwhile and good way to 2
establish a positive safety case that's thorough early 3
on.
4 I think it's also going to be something we 5
want to leverage to defend things like our safety 6
classifications so that they don't drag on, that we 7
have an agreed-upon systematic basis for making those 8
determinations, rather than ad hoc determinations 9
based on whatever negotiation we can do, whatever 10 precedent exists.
11 So that experience of developing the PRA 12 and going through the LMP, I think, has been overall 13 good and that we have gotten significant insight from 14 that process.
15 I'm not going to speak directly to the 16 limits and conditions of the topical here, but I did 17 want to say that has been our overall experience with 18 LMP. Yes, it's a lot of work, but it gives worthwhile 19 insights.
20 MR. WILSON: This is George Wilson of 21 TerraPower. We expected that we were going to get 22 limitations and conditions on the topical report for 23 where we were at.
24 We just wanted to make sure that the NRC 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
128 was open, our logic was there, and the regulatories 1
flow past so that we can continue through the process.
2 So we expected the limitations and the conditions that 3
we received.
4 MR. BLEY: Gentlemen, thanks.
5 CHAIR ROBERTS: Are there any other 6
questions for the staff or the applicant? Now is the 7
time on the agenda for comments from members of the 8
public. If anybody online would like to make a 9
comment, please go ahead and unmute yourself, state 10 your name and organization, and make your comment.
11 Hearing none -- there is a hand, okay.
12 What does the hand mean?
13 MR. LYMAN: Ed Lyman.
14 CHAIR ROBERTS: Yes, hello. Go ahead.
15 MR. LYMAN: This is Ed Lyman from the 16 Union of Concerned Scientists. I'd just like to bring 17 up one point. I've heard from a reliable source that 18 the estimated capital cost of this project has doubled 19 from original estimates.
20 I don't know if that means from the $4 21 billion that was originally stated, meaning you would 22 be up to $8 billion. Clearly, the molten salt storage 23 aspect is a substantial contributor to that capital 24 cost.
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129 I would anticipate there may be design 1
changes along the way to try to address the capital 2
cost increase that could impact the conclusions now 3
that we've reached here. So I'm just raising that as 4
an issue, perhaps for the committee to keep in mind, 5
but some of these redundancies may go away. Thank 6
you.
7 CHAIR ROBERTS: Thank you. Are there any 8
other members of the public that would like to make a 9
statement?
10 Hearing none and seeing no additional 11 hands raised, now is time for the Committee 12 discussion. I guess I'll start by suggesting from 13 what we heard today, I would suggest that we would not 14 need to write a letter because of various reasons.
15 One is the limitation condition number 2 16 in the topical report. Basically you can go through 17 this whole line of reasoning on the actual design as 18 it's produced.
19 There's nothing really that's being 20 committed to at this point other than acknowledging 21 that the process leads to the types of interaction 22 that you've heard today. I'd be interested from the 23 members if people see it that way or have different 24 views.
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130 MEMBER MARCH-LEUBA: I'm a proponent of 1
not writing those when it's not needed. Whenever 2
there is a new and novel concept in its first 3
application, I think in years later will have value.
4 The energy out from Nuclear Island is the first time 5
I've seen it implemented. I think having a position 6
for FCRS is okay.
7 MEMBER HALNON: I absolutely hate agreeing 8
with Jose, but I think that it serves a couple of 9
purposes. One is there's a couple of items that I 10 think we still need to keep our eye on.
11 That is the requirement for the operators 12 to maintain pre-existing conditions prior to a 13 transient in order for that operating envelope to say 14 within the bounds of where it needs to be so that they 15 don't have to respond to an accident condition.
16 That's more on the nuclear side than 17 Energy Island side, but I'm interested in the how tech 18 specs would roll out, procedures, EOPs, and those 19 types of things before we could say that we agree, 20 there's a clear distinction here where there's no 21 license operators on Energy Island.
22
- Secondly, to Jose's
- point, it's a
23 progressive aspect of our committee to give a green 24 light, if that's what we're going to be, which I think 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
131 we should be, to a novel concept to move forward with.
1 I think we concluded, or at least I concluded in my 2
mind, that both the staff and the applicants have done 3
a good job to lay groundwork for future work that has 4
a clear success path, but there's still some hurdles 5
to get beyond.
6 Not just the exemptions, but some of the 7
other analyses that have to be done. I think there's 8
a good aspect to putting a green light on that, but 9
also the cautionary aspect of some things that still 10 need to be shaken out.
11 MEMBER REMPE: I agree with the members 12 who have spoken, except that I have more problems with 13 agreeing with Greg than Jose.
14 MEMBER PETTI: I'm just concerned with how 15 we write such a letter. It's kind of like a green 16 light but putting your foot on the break because 17 there's these issues out there that you really can't 18 evaluate until the design gets more mature.
19 So if we do it, it's going to have to be 20 really carefully worded. Is it viewed as a full green 21 light? The staff didn't give them the full green 22 light. This is kind of a blinking yellow at best.
23 We don't usually write letters like that.
24 I think we're going to see this is all going to come 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
132 back again. It's sort of an issue of when is the 1
optimal time.
2 MEMBER REMPE: There are some things that 3
we will be evaluating as we go forward. It's not 4
really cautions. It's just, hey, there's some 5
outstanding.
6 I'm sorry I interrupted you, Vesna. Go 7
ahead.
8 MEMBER DIMITRIJEVIC: That's okay because 9
that's the limits of my ability to participate in this 10 discussion. This is just conceptual, the approach.
11 So I don't really think that there is a 12 reason for us to write the letter before the design is 13 complete. They're still going to talk with us about 14 human factors that we don't completely understand yet 15 until the PRA is completed.
16 So basically, what they have been saying 17 is technically that Energy Island can be separated 18 from Nuclear Island. And therefore, the components 19 there would not require the same certification, but 20 this is just concept until these other things are 21 complete.
22 MEMBER BROWN: This is Charlie. Are you 23 finished, Vesna?
24 MEMBER DIMITRIJEVIC: Yes.
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133 MEMBER BROWN: I guess I would agree with 1
Tom and Vesna. They've just laid out a concept for 2
how we would like to go. They've given us the plant 3
concept for how to get separation, but there's a whole 4
pile of additional items that need to be evaluated 5
relative to exemptions and the limitations and 6
conditions, which we don't have any closure on at all.
7 I would prefer to have some more detail of 8
how they're actually going to finish rowing the boat 9
through these rapids before we write a letter on it 10 because right now, all we can say is maybe. So I 11 would vote for no letter at this particular time.
12 That would be my position.
13 MEMBER BALLINGER: This is Ron Ballinger.
14 From the standpoint of the technical side, I agree 15 with Tom. We don't need a letter. But what we're 16 talking about here is something which has a much 17 larger implication going forward.
18 What we're talking about here is basically 19 spending reserve for these plants. In the future, 20 it's like putting a battery on the grid in effect, and 21 not having the transmission lines from a freaking --
22 excuse my French -- from a wind turbine somewhere.
23 So going forward, having the Energy Island 24 separated from the Nuclear Island has implications 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
134 which we may want to at least point out. I don't know 1
whether we want to do that in a letter or not, but 2
this concept has larger implications, although people 3
say it's existed for a long time. What's the 4
difference between that and pump storage, I guess.
5 MEMBER HALNON: If you go just a little 6
bit further, Ron, it may not be an Energy Island. It 7
may be a chemical plant. You don't want to put 8
nuclear licensed operators at a chemical plant because 9
they could indirectly affect reactivity by changing 10 their chemical processing. So it's got further 11 implications even broader than that.
12 It's also -- correct me if I'm wrong --
13 this is the first licensing action that TerraPower has 14 asked for. Is that correct?
15 PARTICIPANT: This is the first time.
16 MEMBER HALNON: To show progress in the 17 advanced reactor world, I think it's important that we 18 show the committee is engaged and going forward. Yes, 19 we don't give a complete green light, I agree, to the 20 separation of Energy Island from Nuclear Island.
21 I think it's even beyond conceptually when 22 we see a clear path. There's regulatory hurdles to 23 get over, but they're regulatory hurdles, not 24 necessarily physical. There might be one or two 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
135 physical ones that we pointed out. I think it's 1
important for us to endorse a potential path forward 2
for not just energy islands but chemical process 3
plants, hydrogen plants.
4 MEMBER BALLINGER: In theory, they could 5
shut that down from the salt loop to the Nuclear 6
Island, and just run the turbine and generate power 7
until they ran out of heat.
8 MEMBER HALNON: Yes, until the tank is 9
empty.
10 MEMBER REMPE: Okay. The letter would not 11 occur until October Full Committee week if it were to 12 occur. So I would recommend that you take a vote 13 through the subcommittee and then during P&P September 14 Full Committee, it will become an official committee 15 decision on this.
16 So why don't you give a recommendation to 17 go forward or not to go forward from the subcommittee.
18 And then you'll have to present it at full committee 19 in September.
20 If it does not go forward, you need to 21 have a paragraph that could go into them needing 22 summary notes. I don't think there's more than a 23 subcommittee could do right now. You might want to 24 take a vote and decide what the consensus or the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
136 majority is.
1 MEMBER MARCH-LEUBA: The subcommittee does 2
both, right?
3 MEMBER REMPE: You can have a soft P&P and 4
have a recommendation for the subcommittee. That's 5
what I'm trying to say. I hear both sides of the 6
aisle and I'm kind of stepping in to help you out 7
here.
8 CHAIR ROBERTS: Okay. So our subcommittee 9
vote would be to enter P&P with a recommendation to 10 either write a letter or not write a letter for 11 presentation at the October meeting?
12 MEMBER REMPE: If there is going to be a 13 letter, then there would be a presentation in October.
14 The one question I didn't hear asked is did the staff 15 or the applicant request a letter from ACRS?
16 It does cost the applicant to take time to 17 do a presentation. You can do it remotely. You don't 18 have to fly in or anything.
19 MS. SUTTON: Neither the staff nor the 20 applicant requested a letter. I know we do have a 21 proposed date for October 4th if it was needed. So I 22 guess we will know in September if we will support a 23 full committee.
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137 having to wait until that October -- are there 1
decisions being made by the applicant or the staff 2
other than you can't issue your SC without our letter 3
if we're going to have a presentation? But there's 4
nothing like a real operating plant. Sometimes we're 5
delaying something but we're not really.
6 MS. SUTTON: There's no ground-breaking.
7 There's no construction being done, no construction 8
activities. So at this time we just have several 9
topical reports. We have six in house that we're 10 reviewing that will potentially come to the 11 subcommittee.
12 MEMBER HALNON: Is it required that we 13 have a full committee presentation? Since the 14 subcommittee is the full committee, why can't we just 15 say let's have a one-hour deliberation and then go 16 into letter writing?
17 MEMBER REMPE: Are there any members not 18 present today?
19 MEMBER HALNON: That is an option.
20 MEMBER MARCH-LEUBA: What we do in this 21 case is we ask the staff to make a summary 22 presentation of ten to 15 minutes, and have the 23 applicant on the phone in case there's a question.
24 MEMBER HALNON: Just in case there's some 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
138 lingering questions.
1 MEMBER MARCH-LEUBA: They don't have to 2
travel.
3 MEMBER REMPE: Absolutely, yes. They 4
don't have to. Anyway, I'd take some sort of vote on 5
the recommendation.
6 CHAIR ROBERTS: Let's go ahead and take a 7
vote. The vote would be on whether a P&P coming up in 8
two weeks, whether it's the recommendation of the 9
subcommittee that the full committee meet to 10 deliberate a letter.
11 Does that make sense? A yes vote would be 12 to proceed with a letter and a no vote would be to not 13 proceed with a letter. How would you vote?
14 MEMBER KIRCHNER: I personally would make 15 a summary and not do a letter. My reasons would be 16 that I think we would find ourselves repeating all the 17 limitations and conditions that the staff has 18 discussed as parent of their deliberations in FC.
19 I'm not sure that this would really --
20 again, we're at a conceptual phase. There are lots of 21 questions yet that will depend on the details that 22 will be forthcoming for the applicant. So I guess at 23 this point, I would not write a letter, just put a 24 summary entry into our record.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
139 CHAIR ROBERTS: Thanks, Walt.
1 Vesna?
2 MEMBER DIMITRIJEVIC: Same here. I 3
already said that, a summary note.
4 CHAIR ROBERTS: Let's get a show of hands 5
in the room of who would write a letter? And who 6
would proceed with writing a summary and the P&P but 7
not form a letter?
8 The vote is five plus two, so seven to 9
four to proceed on the basis of not writing a letter.
10 I'll draft a paragraph for the P&P coming up in two 11 weeks, and then we'll have another discussion and 12 another vote at that point.
13 MEMBER MARCH-LEUBA: Procedurally, you 14 would present a recommendation of the subcommittee to 15 the full committee. Hopefully, nobody will change 16 their mind. The decision would be on the full 17 committee.
18 CHAIR ROBERTS: Okay. Thanks, Jose.
19 MEMBER MARCH-LEUBA: The staff and 20 applicant can probably assume that you won't write the 21 letter, but you won't know until September.
22 MS. SUTTON: This is Mallecia. I just want 23 to clarify. Is the vote to actually write a summary?
24 And if no summary, then we'll have the October 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
140 meeting? No letter but the summary of the meeting?
1 MEMBER REMPE: Just to clarify, this 2
summary is just, hey, the subcommittee met. We 3
discussed this. The general people were favorable.
4 We supported the LNCs, the limitations and conditions, 5
whatever comments. You're done.
6 CHAIR ROBERTS: This is our record that we 7
made a decision not to do a letter.
8 MS. SUTTON: I just wanted to make sure we 9
are on the same page. Thank you.
10 MEMBER BROWN: You're clean.
11 MR. MOORE: This is Scott Moore, the 12 Executive Director. We prepare a summary for each full 13 committee meeting. It would go into that. The summary 14 is publicly available in ADAMS. It would describe 15 whatever the full committee decides to do on this.
16 The full committee could still decide to 17 write a letter, as Jose has pointed out, but it's 18 unlikely given that you've got, I think, everybody 19 here. You can see it in the summary and so can the 20 public.
21 MEMBER REMPE: Sometimes an applicant or 22 licensee likes that summary saying that even though 23 they didn't write a letter, they supported it.
24 MEMBER BROWN: Our summary can have a 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
141 caveat that we reviewed all the stuff and it's not 1
unreasonable, but no closure on things, however Tom 2
can phrase it in a happy manner.
3 MR. KELLENBERGER: So we would know in 4
September whether we need to come back for the full 5
committee in October?
6 CHAIR ROBERTS: No surprises.
7 MEMBER REMPE: We'll make sure to let you 8
know.
9 CHAIR ROBERTS: Are there any other 10 comments that the members or consultants would like to 11 make?
12 MEMBER HALNON: Just thank you to 13 TerraPower for coming in. We greatly appreciate face-14 to-face communications when we can get it, so we 15 appreciate it very much that you were here.
16 CHAIR ROBERTS: I'd like to reiterate what 17 Greg said. I appreciate the presentations from both 18 TerraPower and NRC staff. They were excellent. I 19 think our questions got answered to the extent that it 20 could be answered given the preliminary nature of the 21 concept design.
22 With that, this meeting is adjourned.
23 (Whereupon, the above-entitled matter went 24 off the record at 11:29 a.m.)
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
Staff Review of NATD-LIC-RPRT-0001, Regulatory Management of Natrium Nuclear Island and Energy Island Design Interfaces Mallecia Sutton, Senior Project Manager, NRR/DANU Reed Anzalone, Senior Nuclear Engineer, NRR/DANU Jesse Seymour, Senior Reactor Engineer (Examiner), NRR/DRO
Agenda
- Review Chronology
- TR Overview and Review Strategy
- Safety Evaluation Overview
- Plant design and transients
- Safety classification using NEI 18-04
- Regulatory evaluations
- Limitations and conditions
- Conclusions 2
Review Chronology
- Pre-Application Public Meeting
- November 17, 2021
- Submittals on Decoupling Strategy
- White Paper: Energy Island Decoupling Strategy February 4, 2022 (voluntarily withdrawn)
- Topical Report: Regulatory Management of Natrium Nuclear Island and Energy Island Design Interfaces October 4, 2022
- TR Accepted
- November 16, 2022
- Audit Conducted
- January 23, 2023 - March 10, 2023
- Final Draft Safety Evaluation Issued
- August 10, 2023 3
TR Overview and Review Strategy
- Purpose of TR:
- The independence of operation between the systems contained within the NI and the plant systems composing the EI is a key aspect of the Natrium design philosophy.
The NI boundary conditions have been intentionally designed so the interrelationship with the EI does not impact the NI safety case.
- [E]valuate regulatory impacts of the Natrium design interfaces with respect to the interaction of NI and EI systems
- Review Strategy
- Examine key aspects of Natrium design and analysis presented in the TR
- Assess regulatory evaluations in the context of these key aspects
- Propose appropriate limitations and conditions necessary for evaluations to be acceptable 4
Safety Evaluation Overview
- Sections 1 Introduction and Background
- Section 5 - Staff Evaluation
- Section 5.1 - Natrium Plant Design and Transients
- Section 5.2 - Natrium Safety Classification of SSCs
- Section 5.3 - Regulatory Analyses
- Section 6 - Limitations and Conditions
- Section 7 - Conclusions 5
Plant Design and Response to Transients SHX NI EI PHT IHT IAC RAC TSS SGS Images sourced from NATD-LIC-RPRT-0001, Regulatory Management of Natrium Nuclear Island and Energy Island Design Interfaces (ML22277A824) 6 6
Safety Classification Using NEI 18-04*
- NEI 18-04 endorsed in RG 1.233, Guidance for a Technology-Inclusive, Risk-Informed, and Performance-Based Methodology to Inform the Licensing Basis and Content of Applications for Licenses, Certifications, and Approvals for Non-Light-Water Reactors
- Risk-informed, performance-based safety classification is integrated with other aspects of NEI 18-04 process, including selection and analysis of licensing basis events and evaluation of defense-in-depth adequacy
- Different definition for safety-related SSCs than 10 CFR 50.2
- NEI 18-04, Risk-Informed Performance-Based Technology Inclusive Guidance for Non-Light Water Reactor Licensing Basis Development, Revision 1 (ML19241A472) 7
Safety Classification Using NEI 18-04 From NEI 18-04, Rev. 1 (ML19241A472) 8
Role of F-C target in Safety Classification DBEs High Consequence BDBEs Only SR SSCs available to keep DBAs below 10 CFR 50.34 dose limit From NEI 18-04, Rev. 1 (ML19241A472) 9 9
Overview of Regulations Covered in TR
- 10 CFR 50.10, License required; limited work authorization
- 10 CFR 50.65, Requirements for monitoring the effectiveness of maintenance at nuclear power plants
- 10 CFR 50 Appendix B, Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants
- 10 CFR 55, Operators Licenses 10
10 CFR 50.10 (LWA rule) Overview
- 10 CFR 50.10(c): [n]o person may begin the construction of a production or utilization facility on a site on which the facility is to be operated until that person has been issued either a [construction permit] or a limited work authorization [LWA].
- 10 CFR 50.10(a)(1) provides scoping criteria defining construction.
- Rule issuance FRN (72 FR 57415) notes that scoping criteria were chosen to encompass those SSCs that have a reasonable nexus to radiological health and safety or common defense and security.
11
Activities constituting construction are the driving of piles, subsurface preparation, placement of backfill, concrete, or permanent retaining walls within an excavation, installation of foundations, or in-place assembly, erection, fabrication, or testing, which are for:
(i) Safety-related structures, systems, or components (SSCs) of a facility, as defined in 10 CFR 50.2; (ii) SSCs relied upon to mitigate accidents or transients or used in plant emergency operating procedures; (iii) SSCs whose failure could prevent safety-related SSCs from fulfilling their safety-related function; (iv) SSCs whose failure could cause a reactor scram or actuation of a safety-related system; (v) SSCs necessary to comply with 10 CFR part 73; (vi) SSCs necessary to comply with 10 CFR 50.48 and criterion 3 of 10 CFR part 50, appendix A; and (vii) Onsite emergency facilities, that is, technical support and operations support centers, necessary to comply with 10 CFR 50.47 and 10 CFR part 50, appendix E.
12
10 CFR 50.10(a)(1) Evaluation Criterion TerraPower Staff (i)
Not applicable because EI SSCs are NST.
Reasonable, consistent with NEI 18-04 safety classification definition. See L&C 3 regarding definition of safety-related.
(ii)
Not applicable because EI SSCs are not used to mitigate accidents or transients or used in EOPs.
Consistent with plant design. Would not expect NST SSCs to participate in mitigation or prevention.
Not enough information on EOPs. See L&C 5.
(iii)
Not applicable because NST SSCs would not be capable of preventing SR SSCs from fulfilling safety functions.
Consistent with NEI 18-04 safety classification definition.
(iv)
Applicable because failure of EI SSCs could eventually cause a reactor trip.
Plan to seek exemption. Exemption basis would be the same for 10 CFR 50.10(a)(1)(iv) and 10 CFR 50.65(b)(2)(iii).
Agree with determination that criterion is applicable.
Reasonable to use same exemption basis for 10 CFR 50.10(a)(1)(iv) and 10 CFR 50.65(b)(2)(iii). Not taking a position on prospective exemptions. See L&C 10.
13 13
10 CFR 50.10(a)(1) Evaluation Criterion TerraPower Staff (v)
Not applicable because no physical security program SSCs are on EI; CDAs will not be installed on EI prior to CP.
Appears consistent with design, but not enough information to support. See L&C 6.
(vi)
Not applicable because fires on EI will not prevent ability to maintain and achieve safe shutdown.
Adequate because EI SSCs are NST and safe shutdown can be achieved and maintained solely with NI systems.
(vii)
Not applicable because onsite emergency facilities will not be located on EI.
Consistent with plant design, but not enough information to support. See L&C 7.
14 14
10 CFR 50.65 (Maintenance Rule)
- Requires licensees to have a program that monitors the performance or condition of certain SSCs or demonstrates the performance or condition of these SSCs through appropriate preventative maintenance, to provide reasonable assurance that they are capable of fulfilling their intended functions.
- Scope of SSCs considered under the Maintenance Rule are in 10 CFR 50.65(b)
- 10 CFR 50.65(b)(1) is similar to 10 CFR 50.10(a)(1)(i)
- 10 CFR 50.65(b)(2)(i) through (iii) are identical to 10 CFR 50.10(a)(1)(ii) through (iv) 15
10 CFR 50.65 Evaluation
- TerraPower did not evaluate 10 CFR 50.65(b)(1).
- TerraPower determined criteria (i) and (ii) are not applicable. Staff discussions and conclusions are the same as for 10 CFR 50.10(a)(1)(ii) and (iii).
- TerraPower determined criterion (iii) is applicable and plans to seek an exemption. Staff discussion and conclusions are the same as for 10 CFR 50.10(a)(1)(iv).
16
- Appendix B applies to all activities affecting the safety related functions of SSCs that prevent or mitigate the consequences of postulated accidents that could cause undue risk to the health and safety of the public.
17
10 CFR 50, Appendix B Evaluation
- TerraPower asserted that all EI SSCs will be NST, and SSCs classified as NST under the NEI 18-04 process are not capable of affecting the SR functions of SSCs used for prevention or mitigation.
- Staff considered the role of NST SSCs and determined TerraPowers evaluation was acceptable
- RG 1.233 Staff Position C.2 states, in part: The staff expects that SSCs that provide essential support (including required human actions) for SR or NSRST SSCs will be classified in a manner consistent with the higher-level function, even if the supporting SSC is not explicitly modeled in the PRA.
18
- TerraPower states that the Natrium design removes direct interaction between the reactor and the turbine generator
- Turbine operations would not be an apparatus or mechanism whose manipulation directly affects the reactivity or power level of the reactor
- Natrium design should allow for a non-licensed individual to fully operate the turbine generator
- Staff evaluated that the nature of the TSS is consistent with Natrium not treating turbine generator operations as a control as defined under 10 CFR 50.2 and 10 CFR 55.4
- A key consideration is the term direct and its specific meaning within the definition of controls 19
- The AEA Section 11 defines operators as individuals who manipulate the controls of utilization facilities; definition of controls is left to the NRC
- Section 107 further mandates that individuals who operate utilization facility controls must be licensed by the NRC.
- Manipulation of the controls is restricted to licensed operators under 10 CFR 50.54(i)
- Definition of controls in Parts 50 & 55 dates back to 1963 (28 FR 3197)
- Narrowed from an earlier, broader definition; FRN notes that this [current] narrower interpretation is in accord with the original Commission intent.
- The direct aspect of a control means they cause reactor power level or reactivity changes without needing something intermediate to make that happen
- Natrium TSS is a significant intermediary from a reactivity standpoint 20
L&C 1 - Key Aspects of Natrium Design
- Applicants referencing TR must use a plant design that is substantially similar to what was discussed in TR. Any deviations from plant design discussed in TR that could affect SE conclusions must be justified when the TR is referenced.
- Staff underscores the importance of the design features that enable the independence of the NI and EI. While the regulatory evaluations may be relatively high-level, the staffs determinations were made in the context of the Natrium design and its capabilities.
21
L&Cs 2&3 - Safety Classification; Definition of Safety-Related
- L&C 2
- Staffs conclusions rely on the use of the NEI 18-04 process for safety classification and a determination that all EI SSCs are classified as NST.
- Design process is iterative; so is NEI 18-04. As design matures, TerraPower will need to ensure EI SSCs continue to be NST for conclusions to be applicable.
- L&C 3
- Definition of SR in NEI 18-04 is different from that in 10 CFR 50.2.
- Some regulations explicitly reference 10 CFR 50.2 definition rather than simply saying safety-related.
- Use of NEI 18-04 may require exemptions from 10 CFR 50.2 and regulations that refer to it.
22
L&Cs 4 Evaluation of 10 CFR 50.10 and 10 CFR 50.65
- L&C 4 - TerraPower did not address definitions of construction outside of 10 CFR 50.10; this limitation makes the scope of the TR clear.
- L&C 5 - Staff has not reviewed EOPs for Natrium and TerraPower did not discuss in sufficient detail to ensure they do not rely on EI SSCs.
- L&Cs 6&7 - TerraPower did not discuss physical and cyber security programs or onsite emergency facilities in sufficient detail for staff to ensure the EI does not include SSCs that fall under the scope of 10 CFR 50.10(a)(1)(v) and (a)(1)(vii).
23
L&Cs 8 Evaluation of 10 CFR 55
- L&C 8 - 10 CFR 50.54(j) not addressed in TR.
- L&C 9 - Since manipulating the EI does not directly change reactivity or power, operator licensing experience requirements under 10 CFR 55.31(a)(5) are not satisfied by operating the EI.
24
L&C 10 - Prospective Exemption Requests
- TR discussed basis for proposed exemptions.
- Staff reviewed for information but did not take a position on prospective exemptions in the SE.
25
Conclusions TR is acceptable for referencing in future licensing submittals, subject to limitations and conditions.
Plant design and EI SSC safety classification [assumptions] are integral parts of staffs evaluation.
26
Abbreviations BDBE - Beyond design basis event CFR - Code of Federal Regulations CP - Construction permit CDA - Critical digital assets DBA - Design basis accident DBE - Design basis event EI - Energy Island EOP - Emergency operating procedure F-C - Frequency-consequence FR - Federal Register FRN - Federal Register notice IAC - Intermediate air cooling system IHT - Intermediate heat transport system L&C - Limitation and/or condition LWA - Limited work authorization NEI - Nuclear Energy Institute NI - Nuclear island NSRST - Non-safety related with special treatment NST - Non-safety related with no special treatment PHT - Primary heat transport system QA - Quality assurance RAC - Reactor air cooling system RG - Regulatory guide SGS - Steam generation system SHX - Sodium/salt heat exchanger SSC - Structure, system, or component SE - Safety evaluation SR - Safety related TR - Topical report TSS - Thermal salt storage system 27
From NEI 18-04, Rev. 1 (ML19241A472) 28
15800 Northup Way, Bellevue, WA 98008 www.TerraPower.com P. +1 (425) 324-2888 F. +1 (425) 324-2889 August 17, 2023 TP-LIC-LET-0094 Project Number 99902100 U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTN: Document Control Desk
Subject:
Submittal of Presentation Material for Advisory Committee on Reactor Safeguards Subcommittee Meeting This letter provides the TerraPower, LLC presentation material for the August 23, 2023 Advisory Committee on Reactor Safeguards Subcommittee meeting (Enclosure 1).
This letter and enclosures make no new or revised regulatory commitments.
If you have any questions regarding this submittal, please contact Ryan Sprengel at rsprengel@terrapower.com or (425) 324-2888.
Sincerely, Ryan Sprengel Director of Licensing, Natrium TerraPower, LLC :
TP-LIC-PRSNT-0014, Regulatory Management of Natrium Nuclear Island and Energy Island Design Interfaces cc:
Mallecia Sutton, NRC William Jessup, NRC Nathan Howard, DOE Jeff Ciocco, DOE
ENCLOSURE 1 TP-LIC-PRSNT-0014, Regulatory Management of Natrium Nuclear Island and Energy Island Design Interfaces
SUBJECT TO DOE COOPERATIVE AGREEMENT NO. DE-NE0009054 Copyright© 2023 TerraPower, LLC. All Rights Reserved.
Regulatory Management of Natrium Nuclear Island and Energy Island Design Interfaces a TerraPower & GE-Hitachi technology TP-LIC-PRSNT-0014
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Table of Contents
- Natrium'Reactor Overview
- Operational Flexibility
- Transient Separation
- Regulatory Impacts 2
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Natrium Safety Features
- Pool-type Metal Fuel SFR with Molten Salt Energy Island
- Metallic fuel and sodium have high compatibility
- No sodium-water reaction in steam generator
- Large thermal inertia enables simplified response to abnormal events
- Simplified Response to Abnormal Events
- Reliable reactor shutdown
- Transition to coolant natural circulation
- Indefinite passive emergency decay heat removal
- Low pressure functional containment
- No reliance on Energy Island for safety functions
- No Safety-Related Operator Actions or AC power
- Technology Based on U.S. SFR Experience
- EBR-I, EBR-II, FFTF, TREAT
- SFR inherent safety characteristics demonstrated through testing in EBR-II and FFTF Control Motor-driven control rod runback and scram follow Gravity-driven control rod scram Inherently stable with increased power or temperature Cool In-vessel primary sodium heat transport (limited penetrations)
Intermediate air cooling natural draft flow Reactor air cooling natural draft flow -
always on Contain Low primary and secondary pressure Sodium affinity for radionuclides Multiple radionuclides retention boundaries 3
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1 2
3 4
5 6
7 1.
Control Building 2.
Fuel Handling Building 3.
Reactor Building 4.
Reactor Auxiliary Building 5.
Salt Piping 6.
Steam Generation 7.
Turbine Building 1
2 3
4 5
6 7
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Reactor Aux. Building Intermediate Sodium Hot Leg Intermediate Sodium Cold Leg Reactor and Core Intermediate Air Cooling Head Access Area Refueling Access Area Reactor Air Cooling / Reactor Cavity Intermediate Reactor Building Fuel Handling Building Reactor Air Cooling Ducts Spent Fuel Pool (water)
Sodium Int. loop Sodium/Salt HXs Salt Piping to/from Thermal Storage System Ground Level 5
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Energy Island 6
Cold Tank Hot Tank Hot salt pump Superheater Reheater Cold reheat Hot reheat Live steam Steam drum Evaporator Preheater Feedwater Cold salt pump Hot salt from reactor Cold salt to reactor Attemperation pump
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Operational Flexibility 7
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Operational Flexibility Scope of NI command and control
- Licensed Reactor Operator controls reactor power
- Allows NI operators to focus on safely operating the nuclear heat source Reactor power independent of turbine output
- Grid Operator controls turbine output based upon grid demand
- Reactor remains at full power while turbine output variations are accommodated via salt tank inventory management Requirements related to salt tank levels, controlled bands, alert levels, and response times will be verified by initial modeling and reflected throughout design process Immediate reactor plant response to changes in EI heat rejection systems are not necessary 8
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Operational Flexibility
- Molten salt storage tanks change the direct correlation between reactor power and steam demand 9
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Transient Separation 10
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EI Initiated Transients
- All failures associated with the EI are grouped into:
- Loss of or reduced heat removal of IHT system via NSS:
- Loss of salt flow
- High salt temperature
- Low salt pressure
- Increased heat removal of IHT system via NSS:
- Increased salt flow
- Low salt temperature 11
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Initiating Event Screening Meets F-C Target Event Type Line Diagram by Frequency 12 All Events PRA Modeled Events (QHOs Calculated here)
Quantified Events (Assigned a Consequence)
Licensing Basis Events AOO DBE BDBE DBA Other Quantified Events EPZ/Cliff Edge Normal Ops Screening Residual Region DID Only Event Type Line Diagram by Frequency All Events Decreasing Frequency Meets 10 CFR 50.34 dose limits Derived from DBE, no frequency assigned Demonstrates DID adequacy or other important safety feature Evaluates potential for cliff edge and events contributing to EPZ evaluation
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Transient Separation Defense-in-Depth
- Plant safety analyses only model PIEs that directly impact the NI
- All DL3 and DL4 functions are performed by NI systems 13
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Transient Separation With operational flexibility, most events on the EI that would affect the NI in a typical nuclear power plant have no immediate impact EI events can lead to PIEs if resulting change to an interface parameter occurs Plant design ensures that EI SSCs are not required to perform any DL functions other than very few selected DL2 functions on the EI
- Enables no safety-related DL3 SSCs on the EI 14
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Plant Response to EI Transients
- Decrease or increase in heat removal from NSS leads to increased sodium temperature or decreased sodium temperature in IHT respectively
- Thermal inertia in IHT and PHT provides adequate time to respond to the event via signals monitored within NI Power runback:
- Reactor power decreased by insertion of control rods at predetermined rate
- IAC and RAC provide system heat removal
- PSP/ISP flow decreased to target flow settings
- NSS isolation Reactor SCRAM:
- Reactor power decreased by control rod drop via gravity
- IAC and RAC provide system heat removal
- PSP/ISP ramp down
- NSS isolation 15
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Regulatory Impacts 16
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Regulatory Impacts
- Future Exemption Requests
- 10 CFR 50.2, Definitions
- 10 CFR 50.10, License required; limited work authorization
- 10 CFR 50.65, Requirements for monitoring the effectiveness of maintenance at nuclear power plants
- Requirements not applicable to NST SSCs on the EI
- 10 CFR 50 Appendix B, Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants
- Turbine operation by a Licensed Operator is not required
- 10 CFR 55, Operators Licenses 17
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18 Questions?
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AOO - Anticipated Operational Occurrence BDBE - Beyond Design Basis Event CCF - Common Cause Failure CFR - Code of Federal Regulations DBA - Design Basis Accident DBE - Design Basis Event DID - Defense-in-Depth DL - Defense Line EBR - Experimental Breeder Reactor EI - Energy Island EPZ - Emergency Planning Zone F-C - Frequency-Consequence FFTF - Fast Flux Test Facility HXs - Heat Exchangers IAC - Intermediate Air Cooling System IHT - Intermediate Heat Transport System ISP - Intermediate Sodium Pump NI - Nuclear Island NSS - Nuclear Island Salt System NST - Non-Safety-Related with No Special Treatment PHT - Primary Heat Transport System PIE - Postulated Initiating Event PRA - Probabilistic Risk Assessment PSP - Primary Sodium Pump QHO - Quantitative Health Objectives RAC - Reactor Air Cooling System SFR - Sodium Fast Reactor SHX - Sodium-Salt Heat Exchanger SSC - Structure, System, and Component TREAT - Transient Reactor Test Acronym List 19