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Transcript of the Advisory Committee on Reactor Safeguard 669th Full Committee Meeting - December 5, 2019 (Open)
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Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION

Title:

Advisory Committee on Reactor Safeguards Open Session Docket Number: (n/a)

Location: Rockville, Maryland Date: Thursday, December 5, 2019 Work Order No.: NRC-0726 Pages 1-16 NEAL R. GROSS AND CO., INC.

Court Reporters and Transcribers 1323 Rhode Island Avenue, N.W.

Washington, D.C. 20005 (202) 234-4433

1 1

2 3

4 DISCLAIMER 5

6 7 UNITED STATES NUCLEAR REGULATORY COMMISSIONS 8 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 9

10 11 The contents of this transcript of the 12 proceeding of the United States Nuclear Regulatory 13 Commission Advisory Committee on Reactor Safeguards, 14 as reported herein, is a record of the discussions 15 recorded at the meeting.

16 17 This transcript has not been reviewed, 18 corrected, and edited, and it may contain 19 inaccuracies.

20 21 22 23 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

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1 1 UNITED STATES OF AMERICA 2 NUCLEAR REGULATORY COMMISSION 3 + + + + +

4 669TH MEETING 5 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 6 (ACRS) 7 + + + + +

8 THURSDAY 9 DECEMBER 5, 2019 10 + + + + +

11 ROCKVILLE, MARYLAND 12 + + + + +

13 The Advisory Committee met at the Nuclear 14 Regulatory Commission, Two White Flint North, Room 15 T2D30, 11545 Rockville Pike, at 10:45 a.m., Peter 16 Riccardella, Chairman, presiding.

17 18 COMMITTEE MEMBERS:

19 PETER RICCARDELLA, Chairman 20 MATTHEW W. SUNSERI, Vice Chairman 21 JOY L. REMPE, Member-at-Large 22 RONALD G. BALLINGER, Member 23 DENNIS BLEY, Member 24 CHARLES H. BROWN, JR. Member 25 VESNA B. DIMITRIJEVIC, Member NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

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2 1 WALTER L. KIRCHNER, Member 2 JOSE MARCH-LEUBA, Member 3 DAVID A. PETTI, Member 4

5 DESIGNATED FEDERAL OFFICIAL:

6 WEIDONG WANG 7

8 9

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3 1 P R O C E E D I N G S 2 10:47 a.m.

3 CHAIRMAN RICCARDELLA: Okay, so the 4 meeting will come to order. We are going to discuss 5 the GE/GNF control rod drop accident methodology, and 6 the initial part of the meeting is open.

7 MEMBER MARCH-LEUBA: Yes. We will start 8 off with a few minutes of open, then we will close 9 because most of the information is proprietary. So 10 now is --

11 CHAIRMAN RICCARDELLA: Okay. I'll turn 12 the meeting over to Jose March-Leuba, who is chairman 13 of the appropriate subcommittee.

14 MEMBER MARCH-LEUBA: It's called thermal 15 hydraulics.

16 CHAIRMAN RICCARDELLA: Thermal hydraulics.

17 MEMBER MARCH-LEUBA: Okay. So we're going 18 to have some introductory remarks by NFC.

19 MR. OTTO: Okay. Good morning, ladies and 20 gentlemen of the Committee. We're just grateful for 21 the opportunity to present the staff's review of the 22 Global Nuclear Fuel Topical Report. Sitting beside me 23 here is Scott Krepel; he'll be providing the staff's 24 review. We look forward to finishing up today in the 25 full committee.

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4 1 We can have the subcommittee on Tuesday, 2 and we look forward to receiving your letter at the 3 end of your review. So thank you, and we also 4 appreciate working with GE/GNF during the review in 5 closing out all the technical issues associated with 6 this review. So thank you.

7 MEMBER MARCH-LEUBA: So in the interest of 8 time and the GNF/GE, I made the same joke on the 9 subcommittee. Please tell us who you are, and who you 10 work for. Go ahead.

11 MR. HALAC: Hello, my name is Ken Halac.

12 I'm the licensee for fuel licensing for Global Nuclear 13 Fuels, GE Hitachi, and I'm here with Scott Pfeffer, 14 who is our technical lead in the area of control rod 15 drop, among other things at PDH.

16 MR. PFEFFER: Okay, and I'm Scott Pfeffer.

17 As Ken said, I'm the technical leader for the 18 radiological side of the stability and radiological 19 team at GE/GNF. Prior to that I was senior engineer 20 on the stability side of our team as well for a number 21 of years.

22 So without further ado, we'll get into it.

23 So we'll start with an overview of the licensing 24 topical report; just really briefly talk about the 25 drivers, and then the approach we took. And then NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

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5 1 we'll go over very briefly the remaining milestones we 2 got and, obviously, the meetings today and Tuesday, 3 the final licensee and the issuance of the approved 4 LTR. Next slide.

5 Also, the drivers for our development of 6 the LTR here, we're to align with the latest 7 reactivity-initiated accident fuel damage guidelines 8 and more thoroughly evaluate possible CRDA scenarios.

9 So the staff has recently released new guidance, and 10 we wanted to bring you all up to date on that.

11 Improve plan operations: so, allow for 12 more flexibility during startup, which is a critical 13 time for plant operation, and then prevent inadvertent 14 subcriticality events which have been met with LaSalle 15 --

16 MEMBER MARCH-LEUBA: I know we discussed 17 the possibilities. Can you tell us what the 18 subcriticality event is?

19 MR. PFEFFER: Right, yes. So for this 20 event during startup, because of the current 21 requirements in banking at BWRs, the top bank position 22 is at four, dash four, and that doesn't have a lot of 23 worth with a lot of new fuel designs. So during the 24 startup the plant is trying to pull those blades; 25 they've got to pull all the blades to four before they NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

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6 1 can pull any blades further in Groups 3 and 4. When 2 they do that, there's not a lot of worth there.

3 They're just continuing to heat up at that point, and 4 they can actually drop back subcritical if they reach 5 criticality --

6 MEMBER MARCH-LEUBA: So this is --

7 MR. PFEFFER: -- prior to that.

8 MEMBER MARCH-LEUBA: -- going to put in a 9 control role, generally so many (unintelligible) shut 10 you down. Is that correct?

11 MR. PFEFFER: Correct, yes. So they can't 12 get enough reactivity from those --

13 MEMBER MARCH-LEUBA: And it is probably 14 periodic, you'd have pulses, right?

15 MR. PFEFFER: Just very little, because 16 you're just not adding enough reactivity from those 17 pulls to four. So the idea of the new LTR is that 18 we'll be able to provide banks which are more 19 impactful and actually more applicable to the new fuel 20 designs as well, to allow those plants to move 21 appropriately through their startups as well as 22 protect against control rod dropbacks (phonetic).

23 And the last item, there's a dose 24 improvement I just want to demonstrate the goal and 25 the requirement of the LTR to demonstrate zero fuel NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

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7 1 rod failures, and so we'll demonstrate that for CRDA 2 and potentially allow some dose consequence 3 improvements in plants as well.

4 Again, the approach that we took was to 5 utilize previously approved methods, so PANAC or 6 PANACEA is our core simulator. PRIME is thermal 7 mechanical methodology, and TRACG is our BWR system 8 code.

9 When implementing NRC guidance related to 10 specifically hydrogen-efficient gas release models, 11 and then the pellet cladding mechanical interaction 12 and high temperature cladding failure enthalpy 13 thresholds. The PCMI version was originally in 14 Appendix B of Section 4.2. Both of those are now in 15 Draft Guide 1327, which is the draft guidance on 16 reactivity-initiated accidents.

17 And so all these base guidances are listed 18 below. The memoranda is initially on the hydrogen 19 uptake and reactivity initiated accidents 4.2 Appendix 20 B, and then most recently Draft Guide 1327, which has 21 been in development for the past number of years.

22 So documentation status: We had a 23 subcommittee meeting on Tuesday. We were actually 24 here for the full committee today. We expect then, 25 pending this review, final IC in January 2020, and NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

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8 1 then we'll issue the approved version of the LTR at 2 that point in February 2020.

3 And along with that, we'll issue an update 4 to GESTAR-II in 2020, and so the CRDA LTR was 5 submitted with the modifications to GESTAR-II included 6 as part of that package, and so with the approval of 7 the LTR, those modifications to GESTAR will also be 8 approved.

9 Quick background on GESTAR: It's the 10 General Electric Standard Application for Reactive 11 fuel, and it's their process and methodology for 12 plants they have referenced in their tech specs, and 13 as long as they follow the methodologies and 14 requirements that are part of GESTAR, they can 15 implement, for example, the next fuel product line 16 according to those requirements and guidelines in 17 GESTAR-II without additional review and approval by 18 the staff.

19 MEMBER MARCH-LEUBA: Does the GESTAR cover 20 mixed cores? You could take over a plant from 21 Framatome?

22 MR. PFEFFER: So I would say a number of 23 the methodologies specifically have requirements on 24 mixed cores that are part of GESTAR-II.

25 And that's all I have for the open NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

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9 1 session. Are there any other questions?

2 MEMBER MARCH-LEUBA: We'll now have an 3 open session from the staff, and we'll go into closed 4 session later. Remember, we are still in open 5 session.

6 MR. KREPEL: Okay. So we only have a 7 short time, so I'll get started here. My name is 8 Scott Krepel. I will keep this brief. My background 9 is that I graduated from Purdue almost 20 years ago, 10 and then I spent about 10 years working in the 11 industry at TVA.

12 I worked at Elite Analyst for fuel 13 engineering, and then I came to NRC where I've been 14 working ever since for the last 19 years as a safety 15 analyst. I've worked with the research office and 16 with NRR. Now I'm here to discuss GNF and the CRDA 17 application methodology. Next slide, please.

18 So just a short background for everybody:

19 The GE methodology is based on old guidance from 20 about, I think, the '80s.

21 Hold on one second for the interpreter.

22 It was two 80-calorie per gram, and that 23 was limiting from the old guidance. But more recently 24 the research has shown us that NSRR and other 25 facilities who have done simulations, they did rod NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

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10 1 ejection simulations, and that demonstrated the limits 2 were not very conservative.

3 And so with the more recent guidance in 4 place, we have the SRP 4.2, Appendix B, and so that 5 was able to give us a more current guidance for DG 6 1327, which has just been closed for public comment.

7 That will be coming to you soon for review. So the 8 new method that was proposed by GNR does fit the new 9 guidance, DG 1327, much better. Next slide, please.

10 So their method uses their current 11 approved code which you can see listed behind me. As 12 they had different aspects of their analysis, and all 13 of those codes have already been approved and verified 14 by NRC and all significant phenomena.

15 There's been some additional verification 16 that has been done and looked at for the impact of 17 cold conditions for CRDA activities. Okay, next 18 slide, please.

19 So the GNF did not conduct a formal PIRT, 20 which you might be familiar with, but that's basically 21 where they figure out which phenomena are involved in 22 the accident or the incident, and then they assign a 23 ranking of high, medium, or low importance. And so 24 it's this nice, pretty table that we're able to show 25 you. But GNF did not conduct that PIRT.

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11 1 But what they did do is, they identified 2 the phenomena, and they created a report that was a 3 comparison, and so it's another PIRT that's available, 4 and so the NRC as able to review that.

5 And that phenomena was identified by GNF, 6 and it was very consistent with other information that 7 we receive, and it did address the uncertainties that 8 we were looking for. So it was a different approach, 9 but they were able to look using bounding values for 10 parameters as well as demonstrating minimal 11 sensitivity and then creating methodology for 12 conservatism.

13 And there were a few uncertainties that 14 were covered with conservatism, and I will be covering 15 those later in the closed session. Next slide, 16 please.

17 So in summary, I won't repeat everything 18 to you, but everything has been listed in the safety 19 evaluation. There are two important requirements:

20 first, they needed to analyze the CRD events; they 21 also had to look at the radiological release.

22 And so there are some additional 23 requirements as well, such as cooling ability, but GNF 24 and their methodology is actually based and 25 demonstrated that there are no fuel incidents.

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12 1 So we can assume from moving forward, that 2 they meet all the requirements, because there are no 3 radiological release and no loss of cooling.

4 The fuel fair probability evaluation is 5 most useful because the criteria is very similar to 6 the NRC guidance for SRP as well as DG 1327. So with 7 either guidance, they are in compliance, and it is 8 applicable for the licensee to do their analysis.

9 Next slide.

10 So as mentioned briefly, GESTAR-II is a 11 little bit unique. It's unique to GNF and their 12 approach because their licensee is able to implement 13 this methodology without getting further approval by 14 the NRC. They also provide information as needed to 15 support their changing of that fuel, and they will 16 provide clarification as needed about how that 17 methodology or how the information will be updated in 18 the future. That will be discussed a little bit more 19 in depth in the closed session. And that closes my 20 open session of this presentation.

21 MEMBER MARCH-LEUBA: Thank you very much.

22 Can we get --

23 MR. KREPEL: Just a second.

24 MEMBER MARCH-LEUBA: Okay. Can we have 25 any open questions, please?

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13 1 MEMBER REMPE: Yes. Just to make sure, 2 because we're on the record, it's full committee, and 3 it's hardly worth mentioning, but it is worth 4 mentioning. You did agree in our subcommittee that 5 you would correct a statement regarding Draft Guide 6 1327 in the SE before it's issued, correct? Thank 7 you.

8 MR. KREPEL: Yes, that is correct. That 9 is one comment that we are planning to make sure that 10 we correct on the safety evaluation, absolutely.

11 MEMBER REMPE: Okay, thank you.

12 MR. OTTO: And I know we address it in the 13 final safety evaluation, which we're going to complete 14 after this meeting.

15 MEMBER KIRCHNER: Jose, I have two 16 comments. The first, thank you. We will schedule a 17 meeting on DG 1327 at some period. Now, as Scott 18 pointed out, they've closed the public second round of 19 public comments. But my real comment here is, I'm a 20 little puzzled by the erratic blanket statement that 21 GNF satisfies the requirement ensuring that no fuel 22 failures occur as a result of a CRDA. Isn't that 23 dependent on the actual plant application, not the 24 methodology?

25 MEMBER MARCH-LEUBA: Did you want to NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

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14 1 answer it?

2 MEMBER KIRCHNER: We'd prefer.

3 MR. KREPEL: I can answer, yes. Their 4 methodology is specifically intended to allow the 5 licensee to analyze specific plants and then confirm 6 that there are no fuel failures happening at that 7 plant.

8 MEMBER KIRCHNER: I understand that, but 9 which plant? I just don't know -- am I missing 10 something? Is this tied to a specific plant?

11 MEMBER MARCH-LEUBA: Let me -- no, it's 12 not. The methodology is going to determine the bank 13 withdrawal procedures that will be allowable. So if 14 you drop a rod you will not fail any fuel. So if you 15 drop a rod and fail fuel, the bank position is not 16 allowed, and you have to iterate and get a new one.

17 So at the end of the day, for every plant where this 18 is implemented, they will have zero fuel failures by 19 choosing the proper bank positions.

20 MR. KREPEL: Correct.

21 MEMBER KIRCHNER: Correct, I agree. It's 22 just that the methodology doesn't ensure that. It has 23 to be applied to a specific plant and fuel loading, 24 and then you do the analysis. The methodology is 25 being qualified and accepted as a means to make that NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

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15 1 determination.

2 MEMBER MARCH-LEUBA: The methodology 3 requires an interruptive procedure and the use of this 4 further (phonetic) criteria.

5 MEMBER KIRCHNER: Okay.

6 MEMBER MARCH-LEUBA: So the methodology, 7 as we said before, has nothing to do with codes, 8 nothing to do with hydraulics. It's only how you 9 iterate to get it done.

10 MEMBER KIRCHNER: Okay. All right. I 11 missed that subtlety.

12 MEMBER MARCH-LEUBA: How you iterate, by 13 the way, is proprietary, so when we have the letter, 14 we will have to recap.

15 Okay. Can you hit the gavel for a moment?

16 I want us to go into a short recess while we set up 17 the closed session, okay? Are there any public 18 comments from the room?

19 MR. BROWN: Thomas, we need to open the 20 public line.

21 MEMBER MARCH-LEUBA: We don't need one 22 together.

23 Are there any members of the public on the 24 phone line? If you would like to make a comment, 25 please identify yourself and make a comment.

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16 1 MR. HECK: This is Charles Heck of GNF.

2 I'm just commenting so that you know whether or not 3 you can hear somebody.

4 MEMBER MARCH-LEUBA: Thank you. We 5 confirm that the phone line is open, and nobody else 6 wants to make a comment, so at this time we will close 7 the open session.

8 MR. BROWN: Okay. We're going to drop the 9 public line now. GE, we're going to keep the GE line.

10 If you happen to get dropped, please call back into 11 that line, and we will call back in as well.

12 MEMBER MARCH-LEUBA: And GE, can you look 13 around the room and make sure everybody here belongs?

14 I see on this side are all staff members anyway. On 15 that side it's all you.

16 (Whereupon, the above-entitled matter 17 went off the record at 11:06 a.m.)

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Control Rod Drop Accident (CRDA) Application Methodology NEDE-33885P Review December 5th, 2019

Contents for Open Portion Licensing Review

Licensing Topical Report (LTR) Development Overview

Drivers

Approach

Remaining Milestones

ACRS Meetings

Final Safety Evaluation (SE)

Issuance of Approved LTR and GESTAR-II Revisions

LTR Development Drivers

Align with latest reactivity-initiated accident fuel damage guidelines

More thoroughly evaluate possible CRDA scenarios

Improve plant operations

Allow for more flexibility during reactor startup

Prevent inadvertent subcriticality events

Dose Improvements

Demonstrate zero fuel rod failures result from a CRDA

LTR Development (continued)

Approach

Utilize previously approved methods

PANAC, PRIME, and TRACG

Implement NRC guidance

Hydrogen and Fission Gas Release (FGR) models

Pellet Cladding Mechanical Interaction (PCMI) and High Temperature Cladding Failure (HTCF) thresholds

Sources for NRC guidance

NRC Memoranda ML14188C423 (Reactivity-Initiated Accident Acceptance Criteria) and ML15133A306 (Hydrogen Uptake)

NUREG-0800, Sections 4.2, including Appendix B, and 15.4.9

DG-1327 (Control Rod Ejection and CRDA)

Current Status Documentation

ACRS Subcommittee - December 3rd, 2019

ACRS Full Committee - December 5th, 2019

Final SE anticipated January 2020

Issue approved CRDA LTR expected February 2020

Update GESTAR-II expected February 2020

Scott Krepel Office of Nuclear Reactor Regulation, US NRC 1

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Background===

NRC guidance for RIAs has evolved significantly in recent years SRP 4.2 Appendix B DG-1327 Current GNF/GEH methods are based on BPWS NEDE-33885P provides an approach better tailored to current guidance 2

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Background===

NEDE-33885P only covers an analysis procedure; all codes have previously been reviewed and approved by the NRC TGBLA (lattice physics)

PANACEA (3D core physics)

TRACG (thermal hydraulics)

PRIME (fuel rod performance)

Additional validation performed to confirm applicability of codes to limiting CRDA events 3

CRDA Phenomenology GNF did not perform a formal PIRT, however, they did identify all key phenomena in a manner consistent with other references For each phenomenon, the uncertainties were quantified or dispositioned by:

Using bounding values for parameters Demonstrating minimal sensitivity Crediting methodology conservatism 4

Acceptance Criteria Current regulatory requirements may be summarized as follows:

CRDA event must be analyzed GNF provides guidance to assure bounding results Any radiological releases must comply with regulatory limits GNF satisfies this requirement by ensuring that no fuel failures occur as a result of CRDA Possibility of fuel failures evaluated primarily via enthalpy based acceptance criteria consistent with NRC guidance (SRP 4.2 Appendix B, DG-1327) 5

GESTAR & Method Applicability GESTAR II updates to describe relevant documentation requirements (e.g., control rod withdrawal requirements)

Clarifications regarding how methodology can be used New NRC approved models and codes may be used in lieu of those described in the LTR, subject to certain limitations 6

Nomenclature BPWS - Banked Position Withdrawal Sequence CRDA - Control Rod Drop Accident DG - Draft Guide GEH - General Electric - Hitachi GNF - Global Nuclear Fuel LTR - Licensing Topical Report NRC - Nuclear Regulatory Commission RIA - Reactivity Initiated Accident SRP - Standard Review Plan 7

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