ML20023B305
| ML20023B305 | |
| Person / Time | |
|---|---|
| Issue date: | 12/03/2019 |
| From: | Weidong Wang Advisory Committee on Reactor Safeguards |
| To: | |
| Wang, W, ACRS | |
| References | |
| NRC-0732 | |
| Download: ML20023B305 (54) | |
Text
Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION
Title:
Advisory Committee on Reactor Safeguards Subcommittee on Global Nuclear Fuel Licensing Topical Report Subcommittee Open Session Docket Number:
(n/a)
Location:
Rockville, Maryland Date:
Tuesday, December 3, 2019 Work Order No.:
NRC-0732 Pages 1-29 NEAL R. GROSS AND CO., INC.
Court Reporters and Transcribers 1323 Rhode Island Avenue, N.W.
Washington, D.C. 20005 (202) 234-4433
NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 www.nealrgross.com 1
1 2
3 DISCLAIMER 4
5 6
UNITED STATES NUCLEAR REGULATORY COMMISSIONS 7
ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 8
9 10 The contents of this transcript of the 11 proceeding of the United States Nuclear Regulatory 12 Commission Advisory Committee on Reactor Safeguards, 13 as reported herein, is a record of the discussions 14 recorded at the meeting.
15 16 This transcript has not been reviewed, 17 corrected, and edited, and it may contain 18 inaccuracies.
19 20 21 22 23
1 UNITED STATES OF AMERICA 1
NUCLEAR REGULATORY COMMISSION 2
+ + + + +
3 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 4
(ACRS) 5
+ + + + +
6 SUBCOMMITTEE ON GLOBAL NUCLEAR FUEL (GNF) LICENSING 7
TOPICAL REPORT (LTR), NEDE-33885P REVISION 0, 8
"CONTROL ROD DROP ACCIDENT (CRDA) APPLICATION 9
METHODOLOGY" - OPEN SESSION 10
+ + + + +
11 TUESDAY 12 DECEMBER 3, 2019 13
+ + + + +
14 ROCKVILLE, MARYLAND 15
+ + + + +
16 The Subcommittee met at the Nuclear 17 Regulatory Commission, Two White Flint North, Room 18 T2D30, 11545 Rockville Pike, at 8:30 a.m., Jose 19 March-Leuba, Chair, presiding.
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2 COMMITTEE MEMBERS:
1 JOSE MARCH-LEUBA, Chair 2
RONALD G. BALLINGER, Member 3
JOY L. REMPE, Member 4
5 DESIGNATED FEDERAL OFFICIAL:
6 WEIDONG WANG 7
8 9
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3 C-O-N-T-E-N-T-S 1
2 ACRS Chairman Introductory Remarks 4
3 NRC Staff Introductory Remarks 6
4 GNF Staff Introductory Remarks 9
5 CRDA Application Methodology, GNF 6
Background, Submittal Overview
...... 10 7
CRDA Application Methodology
.......... 14 8
Adjourn..................... 29 9
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4 P-R-O-C-E-E-D-I-N-G-S 1
8:51 a.m.
2 CHAIR MARCH-LEUBA: This is a meeting of 3
the Thermal-Hydraulics Phenomena Subcommittee of the 4
Advisory Committee on Reactor Safeguards. I am Jose 5
March-Leuba, Chairman of today's Subcommittee meeting.
6 ACRS members in attendance are Joy Rempe 7
and Ron Ballinger. Weidong Wang of the ACRs staff is 8
the federal official for this meeting.
9 During this meeting the Subcommittee will 10 review a draft safety evaluation report for Global 11 Nuclear Fuel Americas, also know as GNFA, Licensing 12 Topical Report NEDE-33885P Revision O, and GNF-CRDA 13 Application Methodology. The Subcommittee will hear 14 presentations by and hold discussions with NRC staff, 15 GNF-A representatives, and other interested persons 16 regarding this matter.
17 The rules for participation in all ACRS 18 meetings, including today, were announced in the 19 Federal Register on June 13, 2019. The ACRS section 20 of the U.S. NRC public website provides our charter, 21 by-laws, agendas, reports, and full transcripts of all 22 full Subcommittee meetings including the slides 23 presented there. A meeting notice and agenda for this 24 meeting will be posted there.
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5 We have received no written statements or 1
requests to make an oral statement from the public.
2 The first part of today's meeting is 3
opened to public attendance. The second part of the 4
meeting will be closed in order to discuss information 5
that is proprietary to the licensee and its 6
contractors pursuant to 5 USC 552(b)(c)(4).
7 Attendance at this portion of the meeting 8
that deals with such information will be limited to 9
the NRC staff and those individuals and organizations 10 who have entered into an appropriate confidentiality 11 agreement with them.
12 Consequently, we need to confirm that we 13 have only eligible participants in the room for the 14 closed portions when we get there.
15 The Subcommittee will gather information, 16 analyze relevant issues and facts, and formulate 17 proposed positions and actions, as appropriate, for 18 deliberation by the Full Committee.
19 The rules for participation in today's 20 meeting have been announced as part of the notice of 21 this meeting previously published in the Federal 22 Register. A transcript of the meeting is being kept 23 and will be made available as stated in the Federal 24 Register notice. Therefore, we are requesting the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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6 participants in the meeting use the microphones 1
located throughout the room when addressing the 2
Subcommittee.
3 The participants should first identify 4
themselves and speak with sufficient clarity and 5
volume so they may be readily heard. Just a reminder, 6
if your name is in front of you, you don't need to say 7
your name every time you talk. If your name is not in 8
front of you, you tell your name so the court reporter 9
knows who you are.
10 We will now proceed with the meeting.
11 Another reminder. Please place your phones on mute 12 because somebody always forgets and it's annoying when 13 it sounds.
14 Now I'll call on the NRC staff to provide 15 some introductory remarks.
16 MS. ROSS-LEE: Good morning and thank you 17 for your patience with shifting rooms and trying to 18 get all the technology aligned appropriately. My name 19 is MJ Ross-Lee. I'm the Deputy Division Director for 20 the Division of Safety Systems. I want to thank you 21 for coming this morning and for your patience as we've 22 shifted rooms.
23 GNF submitted this topical report in 2008 24 with the intent of implementing the proposed 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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7 methodology into GESTAR II in 2020 as an option for 1
licensees to analyze the control rod drop accident 2
event. GNF's legacy CDRA analysis methodology is 3
based on generic analysis performed to show compliance 4
with old NRC regulatory guidance.
5 The proposed methodology is an updated 6
approach to explicitly verify that the more recent NRC 7
acceptance criteria are met as well as provide 8
flexibility to licensees for analysis on a case-by-9 case basis. New regulatory guidance on reactivity-10 initiated events, accidents in the form of a Draft 11 Guide 1327, will be reviewed by ACRS within the next 12 few months prior to being finalized.
13 In the
- interim, the proposed GNF 14 methodology was reviewed with the criteria from the 15 current guidance in Appendix B to the SRP Section 4.2, 16 as well as the Draft Guide. As a result, the staff 17 expects that licensees will be able to utilize the 18 methodology with the most recent regulatory guidance, 19 whether it be the current SRP guidance or the Draft 20 Guide.
21 The interaction between GNF and NRC staff 22 was very productive in effectively identifying and 23 addressing several potential issues with the finding 24 of applicability of the methodology implementation for 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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8 specific licensees and to clarify potential uses of 1
the methodology not explicitly identified in the 2
topical report.
3 MEMBER REMPE: So I have a question. If 4
I look at your SE, there's a statement in there, and 5
I'm pretty sure it's not proprietary so I can quote 6
it, saying that the time this SE was written, "The 7
Draft Guide is not expected to be finalized." Are you 8
planning to fix that statement?
9 MR. KREPEL: This is Scott Krepel. The 10 Draft Guide was recently finalized. We finished the 11 public comments just a couple of months ago and it's 12 going to go to the ACRS sometime in the next couple 13 months. The safety evaluation is expected to be 14 completed before the Draft Guide becomes finalized as 15 regulatory guidance so the statement will stay as is.
16 MEMBER REMPE: It's a word thing, but if 17 I read this verbatim, at the time this SE was written, 18 Draft Guide 1327 is not expected to be finalized as a 19 regulatory guide. That sounds like ain't never going 20 to happen to me. Probably it should be revised a bit.
21 MR. KREPEL: Sure, I can go ahead and 22 revise that.
23 MEMBER REMPE: Thank you.
24 MS. ROSS-LEE: Yeah, that makes sense now 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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9 as you read it, the wording. It will still be draft 1
but it will be finalized at some point in time.
2 MEMBER REMPE: Sounds like it's never 3
going to happen. Thank you.
4 MS. ROSS-LEE: I understand the question 5
now.
6 CHAIR MARCH-LEUBA: With this discussion 7
we'll pass the gavel to -- for the record, I will call 8
you GE, GEH, GNF, and GNF-A. You let me know what I 9
mean by that. Please tell us what the name of your 10 company is and introduce yourselves.
11 MR. HALAC: Hello. My name is Kent Halac.
12 I work for Global Nuclear Fuels and GE Hitachi. I am 13 here today -- I am the lead licensing engineer for 14 fuel licensing at Global Nuclear Fuels. With me is 15 Scott Pfeffer from Global Nuclear Fuels, GE Hitachi 16 also. He is our technical lead in the area of 17 stability and control rod drop.
18 We appreciate you hearing this topic 19 today. We've come a long ways with this particular 20 methodology and we are looking forward to final 21 closure. We submitted the topical in February of 2018 22 and we had a detailed audit which was scheduled for 23 September 2018 but Hurricane Florence had something to 24 say about that and got delayed to October of 2018 and 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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10 was executed successfully subsequent to the hurricane 1
in Wilmington.
2 Scott Krepel has done an amazing job 3
digesting our technology and providing excellent 4
feedback on the content and narrowing it to be 5
appropriate and consistent with the draft guidance.
6 We have read and have digested the draft 7
SE associated with this and some of the feedback I've 8
received from our consulting engineers is it's 9
arguably the best SE he's every seen. We want to give 10 complements to Scott for his thorough detailed 11 approach toward this particular technology.
12 With that, I will yield to NRC.
13 CHAIR MARCH-LEUBA: I believe you're up.
14 MR. HALAC: Okay, that's right. Sorry.
15 MR. PFEFFER: I'm Scott Pfeffer. I'm the 16 technical lead for the radiological side of the 17 stability and radiological team at GNF GEH. Prior to 18 that I spent eight years on the stability and 19 radiological team mostly doing stability work previous 20 to that.
21 We'll get into the open items on the 22 control rod drop accident methodology. We'll start 23 off with a brief overview of the drivers and the 24 approach that we took in developing the LTR, and then 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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11 a brief discussion on the documentation status, so the 1
REIs, limitations and conditions, and the draft safety 2
evaluation.
3 Drivers, as has been previously mentioned, 4
were to align with the latest guidance from the staff 5
related to reactivity-initiated accident fuel damage 6
guidelines, specifically for CRDA for BWRs. The idea 7
was to more thoroughly evaluate possible CRDA 8
scenarios.
9 We also want to improve plant operations 10 to allow a person more flexibility than is currently 11 available under the old methodology which is a banked 12 position withdrawal sequence methodology. As part of 13 that, we've had some fuel changes and things, some 14 difficulties in start-up at plants, and one of those 15 is an inadvertent subcriticality event that can occur 16 so we wanted to allow some flexibility for that.
17 CHAIR MARCH-LEUBA: Subcriticality?
18 MR. PFEFFER: Subcriticality. The old 19 methodology has some generic requirements on banked 20 positions that must be met during the start-up and 21 mostly developed as part of older fuel designs. The 22 banked at four, which is right at the top of the fuel, 23 especially at BOC conditions, can have very little 24 worth.
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12 During the start-up if they are too slow 1
in pulling those rods, if they can't pull them fast 2
enough with zero worth as the reactor is heating up, 3
they can actually drop and become subcritical. That 4
happened at LaSalle, I believe it was. We wanted to 5
start to allow for flexibility in those banked 6
positions and that's part of the new methodology.
7 As part of that, also looking for 8
potential dose improvements, the goal for our LTR was 9
to demonstrate no fuel failures and that would allow 10 for some benefit in terms of the dose consequence for 11 control rod drop accident.
12 CHAIR MARCH-LEUBA: And this single rod 13 failure, is that the goal, or is it a requirement, or 14 99.9?
15 MR. PFEFFER: It is a requirement of the 16 methodology that we demonstrate as part of our 17 analysis that there are no failures.
18 The approach we used was to use previously 19 approved methods so that includes PANACEA or PANAC 20 which is our core simulator of PRIME or 21 thermal/mechanical methodology, and TRACG BWR systems 22 code to do our analysis.
23 We wanted to implement the newest 24 guidance. We discussed specifically items that were 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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13 implemented were hydrogen efficient gas release models 1
and then the pellet-cladding mechanical interaction, 2
and high temperature cladding failure thresholds as 3
far as the acceptance criteria for rod failures.
4 Sources for that guidance were the 5
memoranda on the RAs and hydrogen pickup, as well as 6
SRP 4.2 Appendix B, as well as then supplemented by 7
Draft Guide 1327 as was mentioned previously.
8 Documentation. The LTR that was mentioned 9
was submitted in February 2018. We conducted the 10 audit in October 2018 and had good discussions there.
11 We resolved all RAIs in March 2019, again after some 12 back and forth and good resolution there.
13 LNC notification along with the draft SE 14 was issued in October with a final SE anticipated in 15 January 2020. At that point we would then issue the 16 approved version of the LTR in 2020 after receiving 17 the final SE.
18 As part of the LTR we also included the 19 required markups for GESTAR II, a General Electric 20 standard application for reactor fuel to allow us to 21 update GESTAR with approved modifications once the LTR 22 for CRDA is approved. Those modifications are part of 23 the LTR and will be part of the improvement.
24 That's all I have for the open session.
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14 Any questions?
1 CHAIR MARCH-LEUBA: Thank you to the 2
presenters. I have to confess while I was writing the 3
draft letter we issued in the full committee, I had 4
serious problems writing anything that was not 5
proprietary and that's why this presentation -- thank 6
you for having given us this.
7 Now we will proceed with the staff 8
presentation open. We are still in non-proprietary 9
session. You will need to turn on your mic.
10 MR. KREPEL: Good morning. I'm Scott 11 Krepel and you should all be familiar with me by now.
12 Just a quick reminder of my background. I graduated 13 from Purdue about 20 years ago now. I've had the 14 honor of studying under some of the former ACRS 15 members there.
16 Then I moved to TVA and I worked there as 17 a fuel engineer for about 10 years. Then I came to 18 the NRC where I've had experience in research, as well 19 as NRR doing licensing reviews for a lot of different 20 thermal-hydraulic events and accident events.
21 I'm sure that it may make it a little easier on 22 you that both of the presenters here today are named 23 Scott so here I am.
24 With no further ado, I'll go ahead and get 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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15 started with my presentation doing a review of the 1
CRDA methodology for GNF. First quick background on 2
this. Previously NRC had guidance for the reactivity 3
initiated accidents for CRDA. Also control rod 4
ejection events for PWRs that was developed quite some 5
time ago. I believe several decades ago. That's 6
fairly old and obsolete at this point.
7 More research from facilities like NSRR in 8
Japan and CARI in France, among others, have provided 9
a lot more information and data on fuel failure during 10 this type of accident event which has led to interim 11 criteria and SRP 4.2 Appendix B which eventually we 12 hope Draft Guidance 1327 will replace and become a 13 permanent guidance for the foreseeable future.
14 Currently the GE methodology is based on 15 BPWS, as the other Scott mentioned earlier. Really 16 that is a generic analysis that is designed to look at 17 the limiting notch worth to determine whether a 18 problem is going to occur or not. This methodology, 19 this new methodology, provides an approach that can be 20 used to explicitly analyze different rod withdrawal 21 sequences and confirm whether they match the current 22 guidance.
23 Next slide. As you see, there are four 24 codes listed here that were used by GNF to be able to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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16 do the analysis. I am not going to talk about TGBLA 1
again but I just have it there so you know it was a 2
cross section that goes to PANACEA. The other three 3
will be discussed further on as different models that 4
were used for direct CRDA analysis, or to provide a 5
bounding parameter for the input.
6 For the most part, we have already 7
validated a lot of the events of concern, but there 8
were some additional validation that needed to be done 9
that we needed to confirm the application of the cores 10 for the CRDA events and the cold conditions.
11 Next slide. I'm sure that you're familiar 12 with CRP 15.0.2 and that's the framework that we've 13 talked about before, but just a reminder that the last 14 two were not addressed explicitly. They were more 15 implicit as part of our review. If I looked at the 16 documentation and understood it, then I made the 17 finding that the documentation was sufficient. Those 18 are the asterisks for those last two.
19 Next slide. Before I talk about specific 20 areas and summarize that for the benefit of the 21 public, if there are any present, I wanted to go ahead 22 and summarize the regulatory acceptance criteria which 23 is outlined here on the slide. There's different SFR 24 50.34, but basically there's just a summary here of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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17 the requirements.
1 First of all, you have to analyze CRDA 2
events and demonstrate that they are bounded by your 3
plant operations and those parameters. Secondly, if 4
a CRDA event happens, you have to look at the dose 5
consequence and it has to be within the design basis 6
limitation. Those are basically the two things that 7
summarize this slide.
8 Next slide, please. In SRP there are 9
specific criteria to demonstrate the regulatory 10 compliance as outlined here. There are interim 11 criteria, but Draft Guide 13.27 has very similar 12 criteria as well. GNF, as already mentioned, their 13 goal with this methodology is no fuel failure.
14 Out of those, it doesn't really matter to 15 GNF for their methodologies since they are going for 16 no fuel failure because then you don't have to worry 17 about the fission gas release and there would be no 18 change in any of the other things as well. We'll be 19 focusing on basically the first two criteria that are 20 listed there which is the high temperature cladding 21 failure.
22 Next slide. There are four areas from SRP 23 15.0.2 that I wanted to talk about. First is that the 24 licensee describes and characterizes the CRDA event 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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18 and identifies the key parameters, output parameters.
1 We've got NFLP for example.
2 NRC staff, me basically, compared their 3
description of the event to the parameters with other 4
PIRTs. For example, GNF did not include a formal PIRT 5
in their topical report, but they did include enough 6
information for me to be able to compare with other 7
vendors' PIRTs, a PIRT that the NRC even developed, 8
for example.
9 Question?
10 MEMBER REMPE: I do have a question.
11 Thank you for noticing. Again, if this is 12 proprietary, stop me. I know in your SE you did talk 13 about it wasn't quite a typical PIRT. Do you want to 14 elaborate or can you about why it differed?
15 MR. KREPEL: Sure. Typically a PIRT is a 16 more systematic approach where you identify a whole 17 list of specific phenomena that are of interest for 18 the accident. Then you assign them a value of either 19 high, medium, or low importance. That is consistent 20 with the NRC approach.
21 GNF didn't formally officially do that in 22 their topical report, but what they did do is provide 23 a description of the phenomena and how they addressed 24 the most important ones. NRC staff identified that 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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19 there were no other phenomena that would be important 1
for this event.
2 MEMBER REMPE: Thank you. That helps.
3 MR. KREPEL: Sure.
4 All right. Next slide. So for the code 5
assessment, as I mentioned earlier on an earlier 6
slide, most of the codes have already been analyzed 7
previously for code fidelity, thermal hydraulic 8
modeling for physics.
9 The only thing is the gap assessment and 10 looking at the cold conditions for reactivity 11 initiated accidents. That was the one little 12 difference. Also looking at the doppler feedback, for 13 example, in previous ones are the turbine trip events.
14 I did an assessment using the SPERT III test.
15 Next slide. For the CRDA evaluation 16 method, there are generally two areas that the NRC 17 staff review; looking at the modeling guidance and the 18 CRDA analysis procedure.
19 Next slide. For the modeling guidance, 20 basically you summarize all of the different 21 recommendations for the input parameters for the 22 modeling and how they model within the code to perform 23 the analysis. They are listed here on the slide and 24 these are generic categories.
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20 Next slide. Yes?
1 CHAIR MARCH-LEUBA: This is still non-2 proprietary but on the fission gas inventory, I assume 3
that information goes from PRIME. Correct?
4 MR. KREPEL: Prime is used to generate 5
some of the information that is used in the analysis.
6 CHAIR MARCH-LEUBA: But the real question 7
is, is it provided how much fission gas is in the 8
cladding in the gap, or the one that is inside the 9
oxide pellet?
10 MR. KREPEL: In the topical report 11 methodology, and I don't know if this is proprietary 12 or not, Scott.
13 MR. PFEFFER: I don't think so.
14 CHAIR MARCH-LEUBA: You need to talk in 15 the microphone. Sorry. Say your name.
16 MR. KREPEL: I'm just trying to avoid 17 proprietary information so just wanted to check in.
18 MR. PFEFFER: This is Scott Pfeffer. I 19 think that question is okay.
20 CHAIR MARCH-LEUBA: Okay.
21 MR. KREPEL: So the methodologies in PRIME 22 to calculate the fission gas that's within the gap, 23 but then it also does more work to then --
24 MR. PFEFFER: One second.
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21 CHAIR MARCH-LEUBA: Okay. Why don't we 1
propose this discussion to the proprietary section.
2 MR. KREPEL: Yeah, that's fine. I plan to 3
discuss it later anyway.
4 Okay. The next section really describes 5
how the actual analysis is performed once you've got 6
the model and then what the actual process is that's 7
done. It formulates basically the heart of the 8
method.
9 There are a lot of steps, step-by-step 10 description of what happens and how to specifically do 11 the controlled run withdrawal sequence and different 12 parameters that may affect the applicability of that 13 order. Of course, you evaluate that against the 14 acceptance criteria.
15 Next slide. The uncertainties. Again, 16 GNF did not do a formal PIRT, but they did identify 17 all of the important phenomena and addressed each one 18 of those for the uncertainties in different ways.
19 There are three listed here, the three 20 different approaches; the bounding analysis 21 parameters, the sensitivity studies, and the analysis 22 conservatism so seeing that conservatism in the 23 analysis. I will discuss all of that later in more 24 detail because most of is proprietary.
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22 CHAIR MARCH-LEUBA: In 20 seconds or less 1
would you describe the methodology as best estimate, 2
best estimate plus uncertainties, or conservative? A, 3
B, C?
4 MR. KREPEL: I would probably characterize 5
it as conservative.
6 CHAIR MARCH-LEUBA: Okay. In LOCA terms 7
would it be an Appendix K type calculation?
8 MR. KREPEL: Not exactly 100 percent 9
Appendix K but, yeah, it is conservative.
10 CHAIR MARCH-LEUBA: Thank you.
11 MR. KREPEL: I mean, Appendix K is very 12 conservative as you know.
13 Next slide. The final area was a little 14 unique to this topical report because, as you may 15 know, GNF has GESTAR II and they allowed the licensee 16 to adopt new methodology right away. They provided 17 updates to their GESTAR II to allow the licensee to 18 adopt new methodology. There are documentation 19 requirements that clarify how that methodology can be 20 used.
21 Jose, do you have a question?
22 CHAIR MARCH-LEUBA: I didn't turn on my 23 green light and he already could foresee my question.
24 Yes, I would like for our education if you can give us 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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23 a one-minute primer on the GESTAR methodology.
1 How does it work? Specifically I'm 2
interested in if I am making a minor update to an 3
existing fuel; for example, I'm changing the inlet 4
filter or a major upgrade like GNF 13 by 13, how does 5
it propagate to a licensee? When does the licensee 6
need an LAR?
7 MR. KREPEL: First, with GESTAR II that is 8
the primary methodology that is documented and it 9
describes all of the other methods that can be used to 10 analyze the fuel. GNF does have a process for the new 11 fuel design and they can assess their new fuel design 12 and then document the details of what is called the 13 fuel compliance document which the NRC can audit at 14 any point. We did actually do an audit for GNF2 and 15 GNF1 fuel design if I recall correctly.
16 CHAIR MARCH-LEUBA: So a licensee on the 17 specifications have a reference to the GESTAR 18 document?
19 MR. KREPEL: Yes.
20 CHAIR MARCH-LEUBA: And then --
21 MR. KREPEL: The tech specs reference 22 GESTAR.
23 CHAIR MARCH-LEUBA: And then GE modifies 24 GESTAR only once, gets it approved through you, and it 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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24 applies to all the licensees. Is that correct?
1 MR. KREPEL: More or less, yes. They do 2
get approval and that includes all of the 3
modifications which is easy, but typically they submit 4
GESTAR amendment topical report that we also review to 5
confirm that everything is A-okay.
6 CHAIR MARCH-LEUBA: Once you issued an SER 7
Amendment 29, then every licensee that references 8
GESTAR can use the fuel. Is that correct?
9 MR. KREPEL: Yes.
10 CHAIR MARCH-LEUBA: Okay. Thank you.
11 MR. KREPEL: One last point here on this 12 final bullet point. As I mentioned, we'll talk about 13 it more later but there were some specific situations 14 where the requesting approval for the use of different 15 ways or methods to do the analysis. Those will be 16 subject to some limitations that we can discuss in 17 more detail later because, again, I don't want to run 18 into proprietary information.
19 Okay, next slide. So overall conclusions.
20 The staff found NEDE-33885P provided good guidance for 21 the use of GNF methodology to do CRDA analyses. We do 22 have four additional limitations and conditions beyond 23 those that already exist for the code that they're 24 using.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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25 I'll talk about those more in detail 1
later, but really they are just affirming the key 2
assumptions are met making sure that the method cannot 3
extend beyond the area of applicability that is 4
expected by the NRC staff when approving this method, 5
or when we plan to approve this method, I should say, 6
assuming that the ACRS is fine with it.
7 Yes.
8 MEMBER REMPE: I have a question. In your 9
SE you talked about the sensitivity of the results to 10 the high end of the enrichment spectrum. I assume 11 that was something near 5 percent. Could you confirm 12 that in the open session? Then how do I know that --
13 what would happen if GE came in with a higher enriched 14 fuel?
15 MR. KREPEL: I expect that kind of 16 situation would be addressed through their control rod 17 worth that explicitly says that is part of their 18 methodology for looking at whether they have higher 19 enrichment. Then that would lead to more release, 20 more heat release, and then that would be captured by 21 the control rod worth.
22 MEMBER REMPE: Just so I know what we're 23 approving if we approve this topical report, are we 24 approving its application for higher enrichment than 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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26 5 percent?
1 MR. KREPEL: I'm not explicitly approving 2
that but I'm not saying that it can't be used for that 3
purpose.
4 MEMBER REMPE: So then, again, I'm not 5
into how this process would work because I just know 6
that -- I'm more into the technical details, but how 7
does that get monitored and checked carefully if that 8
happens because, as you know, it's in discussion right 9
now.
10 MR. KREPEL: Probably the clearest answer 11 is right now PRIME in that methodology has its 12 limitation on burn-up and the applicability for that 13 method.
14 MEMBER REMPE: So for burn-up. What about 15 enrichment? Is it limited to 5 percent?
16 MR. KREPEL: Enrichment I can't recall 17 exactly. I know that with PANACEA there is an 18 assessment database that covers up to 5 percent but I 19 can't recall exactly if there is an explicit 20 limitation in there or not. Maybe GNF has an answer 21 to that.
22 MS. LAMB: This is Shawn Lamb from DNF.
23 We are looking it up right now.
24 CHAIR MARCH-LEUBA: Who was that? Sorry, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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27 what's your name?
1 MS. LAMB: This is Shawn Lamb. I'm the 2
Manager of Stability and Radiological Analysis Team.
3 We are looking up if PRIME has an enrichment 4
limitation right now. We'll get back to you very 5
shortly.
6 CHAIR MARCH-LEUBA: Thank you.
7 MEMBER REMPE: I am interested in that.
8 I started asking that question to GE or GNF or whoever 9
we're talking to but also other --
10 MS. LAMB: Okay, thank you.
11 MEMBER REMPE: It sounds like the rules 12 might change and I just want to know if we're missing 13 something if the rules change. Thank you.
14 CHAIR MARCH-LEUBA: You know that ACRS 15 only speaks through letters so what we're hearing here 16 is subcommittee members opinions. I think even though 17 ACRS has not written a letter, we have made our ideas 18 very clear that if the enrichment is increased 5 19 percent, we would expect a very large review for 20 everybody in this building.
21 It wouldn't be -- all the technical 22 reports automatically apply. Even if you didn't say 23 specifically to apply 5 percent, I think it would be 24 a review of everything. That's what I would expect.
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28 MEMBER REMPE: Expectations. I'm just 1
curious so it's nice sometimes if someone can say, oh 2
yeah, some other method would limit this. Thank you.
3 MR. KREPEL: Understood. Understood.
4 That's a good statement.
5 CHAIR MARCH-LEUBA: We never made any 6
topical reports that says enrichment has to be granted 7
at 1 percent or 5, but if somebody comes up with a 8
natural reactor with.7 and it doesn't apply, you'll 9
have to review it if it's a big change.
10 MR. KREPEL: I know for the perspective on 11 this topical report, I know that I specifically 12 recognized and took a look that the way they 13 approached the applicability in looking at the 14 existing method that they used to analyze it and 15 whether there were any limitations on the methodology 16 would carry over into the new one for the CRDA 17 analysis.
18 MEMBER REMPE: Thank you.
19 CHAIR MARCH-LEUBA: Okay. So we managed 20 to recover all our technical difficulty time and we 21 are ahead of schedule. I would like to propose to 22 have a 10-minute break so we can switch to the closed 23 session. You are free to sit in your original chairs.
24 We are off the record --
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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29 MEMBER REMPE: Public comments.
1 CHAIR MARCH-LEUBA: We are not off the 2
record because we need to ask for anybody in the room 3
who wants to provide a comment because this is the 4
opportunity in the public session.
5 Nobody in the room wants to make a 6
comment. How about the phone? If anybody is on the 7
phone line, could you please say hello to know that 8
it's open?
9 MR. HECK: Hello. This is Charles Heck of 10 GNF. We're hearing you. Can you hear me?
11 CHAIR MARCH-LEUBA: Yes, we can hear you.
12 Does anybody on the phone line have a comment? If so, 13 state your name and provide a comment. We waited a 14 full three seconds and nobody said anything. We will 15 assume we can close the public line now because we are 16 going to go into closed session. You're dismissed.
17 We're on a short recess.
18 (Whereupon, the above-entitled matter went off 19 the record at 9:29 a.m. and resumed at 9:40 for the 20 Closed Session.)
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Control Rod Drop Accident (CRDA) Application Methodology NEDE-33885P Review December 3rd, 2019
©2019 Global Nuclear Fuel - Americas, LLC.
ACRS Meeting / December 3, 2019, Rockville, MD
©2019 Global Nuclear Fuel - Americas, LLC.
ACRS Meeting / December 3, 2019, Rockville, MD Licensing Review
- Licensing Topical Report (LTR) Development Overview
- Drivers
- Approach
- Documentation Status
- Request for Additional Information (RAI)
- Limitations and Conditions (L&C)
- Draft Safety Evaluation (SE)
Contents for Open Portion 2
©2019 Global Nuclear Fuel - Americas, LLC.
ACRS Meeting / December 3, 2019, Rockville, MD 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 3
©2019 Global Nuclear Fuel - Americas, LLC.
ACRS Meeting / December 3, 2019, Rockville, MD 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) 4
©2019 Global Nuclear Fuel - Americas, LLC.
ACRS Meeting / December 3, 2019, Rockville, MD Current Status Documentation
- NRC audit conducted October 2018
- All RAIs resolved March 2019
- L&C notification October 2019
- Draft SE issued October 2019
- Final SE anticipated January 2020
- Update GESTAR-II expected February 2020 5
Scott Krepel Office of Nuclear Reactor Regulation, US NRC 1
=
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
=
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
Licensing Topical Report (LTR)
Review Components 4
SRP 15.0.2 review areas (additional guidance in RG 1.203):
Accident scenario Code assessment Evaluation methodology Uncertainty evaluation Documentation*
Quality assurance*
- Implicitly addressed via GEH/GNF QA program and staff review of supporting documentation for this LTR
Regulatory Acceptance Criteria 5
Current regulatory requirements are defined in:
10 CFR 50.34 - general safety analysis reporting requirement GDC 13 - system parameters must be controlled adequately to bound design basis accidents GDC 28 - reactivity accidents must not damage reactor coolant pressure boundary or impede core cooling 10 CFR 100.11, 50.67 - radiation dose limits
Regulatory Acceptance Criteria 6
Current acceptance criteria to demonstrate regulatory compliance defined in SRP 15.4.9.II:
Reactivity initiated accident criteria (SRP 4.2 App. B)
High temperature cladding failure PCMI cladding failure Core coolability Fission product release inventory ASME reactor pressure vessel limit Note: DG-1327 contains updated criteria that are intended to supplant the current criteria; second public comment period ended October 2019
CRDA Accident Scenario 7
Licensee characterized the CRDA scenario and relevant phenomena.
Critical output parameters are derived from acceptance criteria for CRDA event.
Identification of high importance phenomena is consistent with other available assessments for the CRDA or similar events.
CRDA Code Assessment 8
Assessments from code LTRs Code fidelity Thermal hydraulics models Global core neutron kinetics response CRDA specific assessment SPERT III tests
CRDA Evaluation Methodology 9
Different aspects of the CRDA analysis methodology described in the LTR were reviewed.
Modeling Guidance CRDA Analysis Procedure
CRDA Evaluation Methodology:
Modeling Guidance 10 TRACG Model Nodalization Reactivity Insertion Fission Gas Inventory Initial Parameters Doppler Coefficient Enthalpy Determination
CRDA Evaluation Methodology:
Analysis Procedure 11 At-Power & Cold Zero Power Analysis Parameters Control Rod Withdrawal Order Evaluation Against Acceptance Criteria
CRDA Uncertainties 12 Uncertainties were dispositioned for individual phenomena known to be important for the CRDA event:
Bounding analysis parameters Sensitivity studies Analysis conservatism
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 can be used in lieu of those described in the LTR, subject to certain limitations 13
Conclusions The staff found NEDE-33885P to provide adequate guidance for use of PANACEA and TRACG to perform CRDA analyses.
Limitations and conditions associated with approved LTRs for individual codes remain applicable Four additional limitations and conditions Confirm key assumption (control rod drop speed)
Restrictions on extended applicability of methodology 14
Nomenclature 15 ASME - American Society of Mechanical Engineers BPWS - Banked Position Withdrawal Sequence CFR - Code of Federal Regulations CRDA - Control Rod Drop Accident DG - Draft Guide FGR - Fission Gas Release GDC - General Design Criteria GEH - General Electric - Hitachi GNF - Global Nuclear Fuel LTR - Licensing Topical Report NRC - Nuclear Regulatory Commission NSRR - Nuclear Safety Research Reactor PCMI - Pellet-Clad Mechanical Interaction RIA - Reactivity Initiated Accident RG - Regulatory Guide SPERT - Special Power Excursion Reactor Test SRP - Standard Review Plan
Backup Slides 16
17 Transient FGR Database Revised NSRR database shifted many data points and exposed a more prominent BU-dependence Large spread not unexpected, given spread in steady-state FGR data