ML18264A174
| ML18264A174 | |
| Person / Time | |
|---|---|
| Issue date: | 09/06/2018 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| Snodderly M | |
| References | |
| NRC-3880 | |
| Download: ML18264A174 (129) | |
Text
Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION
Title:
Advisory Committee on Reactor Safeguards Docket Number:
(n/a)
Location:
Rockville, Maryland Date:
Thursday, September 6, 2018 Work Order No.:
NRC-3880 Pages 1-129 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 656TH MEETING 4
ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 5
(ACRS) 6
+ + + + +
7 THURSDAY 8
SEPTEMBER 6, 2018 9
+ + + + +
10 ROCKVILLE, MARYLAND 11
+ + + + +
12 The Advisory Committee met at the Nuclear 13 Regulatory Commission, Two White Flint North, Room 14 T2B3, 11545 Rockville Pike, at 8:30 a.m., Michael L.
15 Corradini, Chairman, presiding.
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2 COMMITTEE MEMBERS:
1 MICHAEL L. CORRADINI, Chairman 2
PETER RICCARDELLA, Vice Chairman 3
MATTHEW SUNSERI, Member-at-Large 4
RONALD G. BALLINGER, Member 5
DENNIS C. BLEY, Member*
6 CHARLES H. BROWN, JR. Member 7
MARGARET SZE-TAI Y. CHU, Member 8
VESNA B. DIMITRIJEVIC, Member 9
WALTER L. KIRCHNER, Member 10 JOSE MARCH-LEUBA, Member 11 HAROLD B. RAY, Member 12 JOY L. REMPE, Member 13 GORDON R. SKILLMAN, Member 14 15 DESIGNATED FEDERAL OFFICIAL:
16 MICHAEL SNODDERLY 17 18 19
- Present via telephone 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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3 CONTENTS 1
Opening Remarks.................
4 2
NuScale Topical Report TR-0915-17564, "Subchannel 3
Analysis Methodology"...........
7 4
NuScale Design Certification Application (DCA),
5 Chapter 7-Instrumentation and Control and 6
Chapter 8 - Electrical Systems
...... 31 7
Adjourn..................... 86 8
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4 P R O C E E D I N G S 1
(8:30 a.m.)
2 CHAIRMAN CORRADINI: I'm sorry we had the 3
microphones on mute. NuScale, are you there and Matt 4
Thomas? Is there anyone on the phone line?
5 MR. LIGENFELTER: Andy Ligenfelter's here 6
from NuScale.
7 CHAIRMAN CORRADINI: Fantastic. Anybody 8
else?
9 MR. GAMBLE: Robert Gamble is here as 10 well.
11 CHAIRMAN CORRADINI: Anybody else? Okay.
12 Thanks. So, I think the best thing to do is, we're 13 going to put you guys on mute. And if you need to 14 speak, then maybe perhaps you could text Paul.
15 And then, Paul can let me know and we'll 16 take you off mute and -- unless, otherwise, if a 17 question comes up and we think we need you, then we'll 18 ask you guys. Does that sound reasonable?
19 MR. LIGENFELTER: Sounds good.
20 CHAIRMAN CORRADINI: Okay. Thanks. The 21 meeting will now come to order. This is the first day 22 of the 656th meeting of the Advisory Committee on 23 Reactor Safeguards. In today's meetings, the 24 Committee will consider the following, the NuScale 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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5 Topical Report on Subchannel Analysis Methodology and 1
the NuScale Design Certification Application for 2
Chapter 7, Instrumentation and Control and Chapter 8, 3
on electrical systems and then, preparation of ACRS 4
reports.
5 The ACRS was established by statute and is 6
governed by the Federal Advisory Committee. As such, 7
this meeting is being conducted in accordance with the 8
provisions of FACA. That means that the Committee can 9
only speak through its published letter reports.
10 We hold meetings to gather information to 11 support our deliberations. Interested parties who 12 wish to provide comments can contact our offices 13 requesting time after the Federal register describes 14 a meeting as published.
15 That said, we also set aside ten minutes 16 for extemporaneous comments from members of the public 17 attending or listening to our meetings. Written 18 comments are also welcome. Mr. Mike Snodderly is the 19 designated Federal official for the initial portion of 20 this meeting.
21 Portions of the sessions on NuScale design 22 certification application may be closed in order to 23 discuss and protect information designed as 24 proprietary. The ACRS section of the NRC's public 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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6 website provides our charter, bylaws, letter reports, 1
and full transcripts of all our full and subcommittee 2
meetings, including all slides presented at the 3
meeting. We receive no written comments or requests 4
to make oral statements from the members of the public 5
regarding today's sessions.
6 There is a bridge, a phone bridge line.
7 And to preclude interruption of the meeting, the phone 8
will be placed in a listen-in only mode during the 9
presentations and committee discussions. In addition, 10 a transcript of portion of the meeting is being kept.
11 And it is requested that speakers use one of the 12 microphones, identify themselves, and speak with 13 sufficient clarity and volume so they may be readily 14 heard.
15 And then, just remind everybody to please 16 turn off your cell phones or put them on silent mode 17 so they don't disturb our proceedings. With that, I'm 18 going to turn the first portion of the meeting over to 19 Walt Kirchner. And Walt, do you want to lay this out?
20 MEMBER KIRCHNER: Yes. We had a good 21 Subcommittee meeting on August 24th, good interactions 22 with the staff and the applicant. I think we'll hear 23 more about that in today's session. And with that, I 24 am going to look to Bruce, and turn it over to you, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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7 Bruce.
1 MR. BAVOL: Okay. Very good. Good 2
morning.
3 VICE CHAIRMAN RICCARDELLA: Just one 4
thing, Bruce. I think I need to recuse myself from 5
these deliberations.
6 MR. BAVOL: Okay. My name is Bruce Bavol.
7 I'm a project manager in the Office of New Reactors.
8 This was the review of TR-0915-17564, Revision One, 9
Subchannel Analysis Methodology for NuScale Project.
10 To my right is the lead for the review, Mr. Syed 11 Haider.
12 He will be discussing an overview of the 13 scope of the review. What I'm going to do is just 14 briefly go over the staff review timeline. Then, I'll 15 turn it over to him. But also, we have -- we'll be 16 going over any of the comments we went through during 17 the Subcommittee meeting to see how that goes.
18 So, our staff review timeline, the NuScale 19 Topical Report was submitted February 15th, 2017.
20 This is Revision One. That was provided as an update 21 for propriety and export control information in the 22 topical report. Staff issued a number of REIs for 23 them and received responses.
24 The applicable information is provided in 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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8 the handout. We plan to issue a final safety 1
evaluation late in October of this year. And then, 2
staff plans to publish an approved version, if all 3
goes well, in the early part of 2019. With that, I'll 4
turn this over to Syed Haider and he can go over an 5
overview of the staff review.
6 MR. HAIDER: Thank you, Bruce. Good 7
morning. My name is Syed Haider. I'm the lead 8
technical reviewer at the NRO for the NuScale 9
Subchannel Analysis Methodology document report, 10 revision one that was submitted in February 2017 and 11 is the subject of today's full committee meeting.
12 I would also like to acknowledge the 13 contributions made to the current review by Matt 14 Thomas, my colleague in the ecosystems branch and Joe 15 Kelly from the office of research. While Matt and I 16 performed the topical reviews and wrote the respective 17 SER sections, Joe performed all necessary viper 18 confirmatory analyses that were needed to support the 19 review.
20 I would also like to thank Bruce Bavol, 21 the PM, sitting next to me, for his effective 22 management of all of our coordination needs with 23 NuScale, was with the ACRS. Now, I'll summarize the 24 highlights of the open and closed session staff 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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9 presentations that I made, during the SER subcommittee 1
meeting on August 24th. A subchannel analysis is 2
typically used to calculate the baseline thermal 3
hydraulic margin for the critical heat flux and the 4
fuse central line temperature that feed into the DCD 5
Chapter 4 and Chapter 15, even to specific safety 6
analysis.
7 The staff conducted the review of the 8
NuScale Subchannel Analysis Methodology Topical 9
report, per general design criterion ten, on from 10 10 C.F.R., Part 50, Appendix A. The related regulatory 11 guide is stipulated in NuScale Design's specific 12 review standard, section 4.4 on thermal and hydraulic 13 design and 10 C.F.R., 50, 34, on the contents of 14 applications and technical information.
15 So, essentially, the NuScale Subchannel 16 Analysis Methodology uses the NRC-approved viper one, 17 subchannel thermal hydraulic computer code to conduct 18 the NuScale fuel design subchannel safety analysis.
19 A viper one code that was doubled-up and has a PWR 20 license and history.
21 It's worth clarifying that there is no 22 viper two subchannel core. And viper one is also 23 interchangeably used -- it's called viper. So both 24 viper one and viper would refer to the same subchannel 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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10 core. Viper has two versions, mark one and mark two.
1 NuScale used the latest viper version, mark two, in 2
the NuScale methodology that was approved in 1993.
3 While the earlier viper version, mark one, 4
was approved by the NRC in 1996, the NRC approval of 5
viper mark one and mark two core versions, is 6
documented through the respective generic NRC safety 7
evaluation reports that are cited.
8 The present slide also lists the four 9
elements of approval for the NuScale Subchannel 10 Analysis Methodology or NSAM, that NuScale applied 11 for, as documented in the topical report. These four 12 elements required the staff to focus on the viper 13 code's applicability to the NuScale steady state and 14 constant subchannel analysis.
15 Number two, whether the methodology 16 fulfills the NRC's requirements specified in the two, 17 generic ESRs issued by the NRC while approving viper 18 versions mark one and mark two. And number three, 19 whether the methodology is independent of any specific 20 CHF correlation and is used for NuScale applications, 21 with an NRC-approved NuScale specific CHF correlation.
22 And lastly, whether the treatment of 23 uncertainties in the NuScale Subchannel Methodology is 24 appropriate. So, the staff's review was focused on 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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11 these four elements of approval that was sought by the 1
applicant for the topical approval. The two generic 2
SERs that document the NRC approval of viper versions 3
mark one and mark two, identify a total of nine 4
conditions and that an application of viper code has 5
to meet.
6 These nine conditions that mainly deal 7
with the viper modeling assumptions and qualifications 8
provided the technical basis for the staff review of 9
the NSAM topical report. Out of the nine conditions, 10 the first five conditions belong to the viper mod one 11 SER, while the later four conditions belong to the 12 viper mod two SER.
13 The evaluation of NSAM topical report 14 against the viper generic SER conditions required the 15 staff to focus on several aspects of the methodology 16 application and the treatment of uncertainties. Even 17 though the generic viper one qualifications for 18 subchannel analysis had been reviewed as a part of the 19 original mod one and mod two approvals, the staff 20 closely looked into certain technical areas to ensure 21 the viper licensing applicability to the NuScale.
22 The staff presented the overriding 23 concerns and the technical details are leading to 24 their resolution during the closed session of the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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12 subcommittee meeting on August 24th. So, now I'll 1
summarize some of the highlights of the August 24th 2
presentations.
3 During the review, the staff raised and 4
resolved questions about the in a sense, applicability 5
gain of the thermal hydraulic parameters and any 6
potential viper code limitation that would be 7
applicable to the NuScale design.
8 The staff performed a
confirmatory 9
analysis to ensure that the NuScale and natural 10 circulation design, normal and off-normal operating 11 conditions in the subchannel and at the core exit, 12 were more typical of EWIs. The staff also ensured 13 that the core-on number criterion is met and the viper 14 numerical solution is stable throughout the various 15 design basis, transients, that were identified in the 16 NSAM topical report.
17 The staff conducted a
confirmatory 18 analysis to ensure the in-led boundary condition 19 consistency between the system level core and re-lap 20 five and the viper subchannel calculations. The staff 21 established that both codes were independently 22 predicting the same, overall pressure drop across the 23 core, which served as an over-arching check on the 24 viper calculations. The staff also performed a 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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13 confirmatory analysis to verify that the viper 1
predictions are not sensitive to the core in-led flow.
2 And the viper solution is well-behaved in 3
the neighborhood of the most limiting viper transient 4
involving concurrent misoperation, single rod 5
withdrawal. The staff also reviewed the viper model 6
geometry.
7 The sensitivity studies the applicant 8
performed which demonstrated the applicability of the 9
axial and radial normalizations and the NSAM 10 assumptions made for the axial and radial power 11 distributions. The staff concluded that the NSAM had 12 an overall conservative approach toward modeling the 13 geometry, normalization, and power distribution.
14 During the closed session on August 24th, 15 the staff also presented its review of the applicant's 16 qualification of key viper models and assumptions, 17 especially, the proofers for models used in the NSAM.
18 In our review, the information the NRC staff 19 considered, in addition to the NSAM topical report, 20 revision one, included the responses to REIs 9080 and 21 its supplement and REIs 9086, 9099, and 9129, as well 22 as the documents NuScale furnished for the audit.
23 MEMBER REMPE: Excuse me. During our 24 meeting -- and again, if I say something that needs to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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14 be answered later in a closed session, we'll deal with 1
it then. But, I'd ask, well, in some cases, the staff 2
said, well, we don't approve the final value.
3 We don't even approve the method, because 4
you didn't fully document on how you got what some of 5
the final values for condition three. And yet, in the 6
final end statement, you said, yeah, we've approved 7
things. And I just want to make sure I understand 8
what you've approved.
9 So, when they come in with their final 10 values for startup with a core loading, are you going 11 to go back and look like, at all the input parameters 12 as well as the processes they used to calculate those 13 values again and say whether they get a thumbs up or 14 down or what exactly did you approve? And I kind of 15 think that's what I asked before.
16 And it's -- when you say you don't approve 17 the values or even the way they calculated it in some 18 of those cases, what -- you know, what did you approve 19 and how will things change later on?
20 MR. HAIDER: Okay. I think you are 21 specifically referring to the example. During the 22 closed session, we tried to make it clear that there 23 were certain example variables. And you are also 24 documenting this at appropriate locations in the SER, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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15 that we are not approving this example variable, which 1
was more of a middle of the range variable that they 2
were using. But, the actual value will be approved 3
when the methodology is applied in the DCB for Chapter 4
4 and Chapter 15.
5 MEMBER REMPE: So, I can understand you 6
didn't approve the example values.
7 MR. HAIDER: The example values.
8 MEMBER REMPE: But, you actually said, I 9
didn't even approve the process you used because you 10 didn't fully document it, and again, in certain 11 places. And I don't have the SE in front of me, but 12 I think in the discussion on values pertaining to 13 condition three.
14 I -- was the radial power distribution, 15 the bypass flows -- there were several of them where 16 you note that the processes were also not approved.
17 MR. HAIDER: Okay. Some of those, whether 18 we found that some of the methodology reserves were 19 not sensitive to some of those parameters that we are 20 considering.
21 MEMBER REMPE: Okay.
22 MR. HAIDER: We had some basis to believe 23 that we could approve these numbers because the 24 reserves were not sensitive to those values. While, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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16 for some other values, the numbers would be reviewed 1
while the NSAM is applied to the Chapter 4, the 2
respective Chapter 4 and Chapter 15 analysis. But, I 3
mean, if you can give me a specific example that is --
4 CHAIRMAN CORRADINI: Maybe we should do 5
that in closed session, if necessary.
6 MEMBER REMPE: Well, I don't even have a 7
-- I'm going to have to -- do you have a printout 8
Walt?
9 MR. KIRCHNER: But, if I just repeat -- I 10 want to make sure that we're clear. The way I read 11 condition three is, there was nothing there that 12 caused you concern on how they met the requirement.
13 But, the proviso is, when I look at 14 Chapters 4 and 15, you're going to have to look at the 15 values chosen and the logic or the justification upon 16 the logic they used to pick those values, because 17 that's specific to the NuScale design.
18 MR. HAIDER: That's correct.
19 MEMBER REMPE: So, that might make me feel 20 good if that is what it said, that again, not only did 21 we not approve the value, we didn't really even 22 approve the logic for it. But again, if something 23 comes in with 4 and 15 that's radically different, 24 you're going to change things. And I guess I didn't 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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17 get that from the discussion or what I saw in the SE.
1 MR. HAIDER: Okay. Okay. But, that is 2
indeed the case.
3 MEMBER REMPE: Okay. As long as that's, 4
again --
5 MR. HAIDER: That's more -- and I can even 6
give you an example.
7 MEMBER REMPE: Okay. That's fine. Again, 8
maybe it's more tradition and I'm not aware of the 9
tradition. But, I was puzzled when I read this 10 because it sounded like, well, we approved it. But, 11 yet, if I look at -- well, we didn't totally approve 12 it.
13 MR. HAIDER: Okay. I think we can go into 14 15 MEMBER REMPE: Okay.
16 MR. HAIDER: Into deeper in the closed 17 session --
18 MEMBER REMPE: Okay. Thank you.
19 MR. HAIDER: So, during the open session 20 of the SER's subcommittee meeting on August 24th, the 21 staff presented how the applicant met the nine 22 conditions from the viper mod one and mod two SERs.
23 During the closed session, the staff provided 24 additional proprietary details of the staff review of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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18 the NuScale Subchannel Analysis Methodology that were 1
used to finalize the safety findings, as documented in 2
the safety evaluation report with no open items and 3
how various REIs and supplements were closed.
4 So, based on the information documented in 5
the safety evaluation report, the NRC staff has 6
reasonable assurance that the use of the viper one mod 7
two code, now with the NuScale subchannel analysis 8
methodology as described in the topical report, is 9
appropriate for the NuScale fuel thermal hydraulic 10 design and plant safety analysis, provided that 11 condition one of the SER is met.
12 The staff also found that sufficient 13 information has been presented by the applicant for 14 its four, requested elements of approval. So, based 15 on its review findings, the staff concludes that viper 16 is applicable to the NuScale's steady state and 17 transient subchannel analysis in using the methodology 18 presented in the NSAM topical report.
19 NSAM fulfills the NRC's requirements, as 20 specified in the two, generic SERs issued for viper 21 mod one and mod two core programs. NSAM is 22 independent of any specific CHF correlation and is 23 used for NuScale applications with an NRC-approved CHF 24 correlation that also meets condition one of this SER.
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19 NSAM describes an appropriate methodology for the 1
treatment of uncertainties in the NuScale subchannel 2
analysis.
3 So far, I have summarized the review and 4
its findings in the open part of my presentation. I 5
would invite any further questions about this staff 6
review of the NuScale subchannel analysis methodology, 7
before we move on to the three suggestions that the 8
SER subcommittee made during the August 24th 9
presentation for the staff of NRC.
10 On August 24th, the SER subcommittee 11 members made three suggestions about the safety 12 evaluation report for the staff to consider. The 13 staff discussed the suggestions, found them valuable, 14 and decided to incorporate all of them into the SER.
15 The staff made those changes in the SER and has 16 forwarded the advance copies of those changes in 17 redline, strikeout, for distribution to the SER and 18 its members.
19 Now, I'll go over each one of the three 20 suggestions and explain what the staff did to address 21 it. The next two slides explain the ACR suggestions 22 and what staff did to incorporate those suggestions 23 into the SER. So, the subcommittee's first condition 24 one, that the staff had developed as a part of the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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20 present staff SER, which is documented in section five 1
of the SER under conditions and limitations. The 2
objective of the SER condition is to ensure that only 3
NRC-approved correlations are used with NSAM.
4 Therefore, an applicant referencing the 5
NSAM topical report in a subchannel safety analysis, 6
would be required to reference an approved CHF 7
correlation. However, the SER has commented that the 8
condition could be made more restrictive to additional 9
ensure that a CHF correlation used for the safety 10 analysis has also been approved using the same NSAM 11 methodology, as the viper-based NSAM methodology was 12 also used to develop a
NuScale-specific CHF 13 correlation, with the same set of frozen viper models 14 and correlations.
15 The staff recognizes the circular nature 16 of relation between the NSAM methodology and the 17 approved CHF correlation. So, the staff also 18 appreciated that its approval of the NSAM methodology 19 for safety analysis partially relied on the fact that 20 the same NSAM methodology was also used which helped 21 allay the staff concerns about any phenomenonological 22 uncertainty due to the extended quality range 23 encountered in the NuScale CHF correlation 24 development. Therefore, as shown on the slide, the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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21 staff has appropriately worded the condition to ensure 1
that the CHF correlation used with NSAM is not only 2
approved by NRC, but it has also been demonstrated to 3
be applicable for use with the NuScale subchannel 4
analysis methodology topical report.
5 So now, the revised, two-part condition is 6
inherently viper-specific, as was suggested by the 7
subcommittee. An advance copy of the redline and 8
strikeout of the revised conditions text has been 9
provided to the SER. The second SER's comment belongs 10 to a section on page 26 of the SER that the staff had 11 titled.
12 The staff agreed that the ACR's comment 13 that such a comprehensive title would be ideally 14 suited for an SER that was dedicated to the subject.
15 The staff sensitivity study presented in the SER 16 section, was limited and only concerned with one 17 aspect of instability within a rather narrow regime of 18 reactor operation for a specific, limiting transient, 19 involving rod misoperation.
20 But, the staff has kept the section in the 21 SER, due to the need to demonstrate a stable viper 22 solution in the NSAM methodology for a range of core 23 in the flow. However, the staff has appropriately 24 changed the title of the section to "Flow 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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22 Participation Sensitivity Study" and has reworded the 1
body of the text accordingly. The staff has basically 2
rewritten this section title and made conforming 3
changes to the first two paragraphs of the section to 4
de-emphasize the instability aspects of the writeup 5
and has, rather, focused on the core inlet flow 6
variations.
7 The staff agrees that our study did not 8
categorically demonstrate that the NuScale power 9
module was not operating near approval and stayed with 10 the point. And such a conclusion was not warranted to 11 approve the subchannel methodology report. An 12 advanced copy of the redlined/strikeout paragraph has 13 been provided to the NCRS.
14 The following final comment from the NCRS 15 was a correction proposed, which is figure one on page 16 10 of the SER. The SER figure was intended to compare 17 viper predictions of the fuel center line composure 18 for the limiting concordance operation case for 19 temparal relations and to conclude that the effect of 20 boiling heat transfer correlation is negligible 21 compared to the available margin, and regardless of 22 the choice of boiling correlation.
23 However, the SER has duly pointed out that 24 the chin and palm curves on figure one were not 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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23 consistent with their descriptions within the body of 1
the text. So, the staff cross-referenced the SER 2
description with the viper predictions and concluded 3
that even though the SER description and conclusions 4
are correct, that the palm and chin legends on figure 5
one had been mistakenly swapped at some stage of 6
editing.
7 I know the staff has made the proposed 8
correction and legends on figure one wholly represent 9
the viper one predictions corresponding to the chin 10 and palm correlation. An advance copy of the 11 corrected figure one has been provided to the NCRS.
12 This concludes my presentation for the open session.
13 The staff would like to thank the NCRS for 14 giving valuable feedback that improved the overall 15 quality of the SER. Now, I would invite any question 16 still outstanding on this matter, again.
17 CHAIRMAN CORRADINI: Joy, did you -- can 18 I ask just a -- did you want to go into closed session 19 to talk about your thing?
20 MEMBER REMPE: Well, again, all I have are 21 my notes, because I don't have a printout of the SE in 22 front of me. But, as my notes indicated that there 23 were several values that you didn't approve, such as 24 the bypass flow, the instrument I-2 bypass flow, inlet 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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24 flow distribution, radial power distribution, major 1
mint and certainty value for delta H, et cetera. And 2
that you note on page 28 of the SE that specific 3
inputs will be approved.
4 In some cases, you said, even the process 5
for getting those values were not approved. So, what 6
I think that you've told me is, well, when the Chapter 7
4 and 15 comes around, we'll look at those values.
8 We'll look at the process they use.
9 And if we don't like the -- and I don't 10 know how you're going to decide the numbers are too 11 far off from what you believe is right. Because 12 you've basically told us, I think, in open session, 13 the values didn't affect the final result. Is that 14 what you said?
15 MR. HAIDER: Some of the values, not all.
16 MEMBER KIRCHNER: No. It's not all.
17 MEMBER REMPE: So, if the --
18 MR. HAIDER: They will also be reviewed.
19 MEMBER REMPE: They'll be reviewed? And 20 what will you use as a basis for reviewing it? I 21 mean, this is something where the applicant as well as 22 the NRC can get into trouble if you have an unclear 23 agreement. And I just am wondering what the basis is 24 that you'll judge it's appropriate or not.
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25 MR. HAIDER: The basis is also documented 1
in the SER, like we were approving and why we were not 2
approving this.
3 MEMBER REMPE: Right. But what will be 4
deemed acceptable? I mean, do you have a -- I don't 5
think I saw in the SER that you had comparison 6
calculations for those values.
7 You said that they -- we didn't like the 8
number or we don't approve the number. We didn't 9
approve the process. So, when will you have a process 10 that you approve?
11 MR. HAIDER: No. That's not true. And 12 for a case for it, I mean, I can give you some example 13 for which we even performed a confirmatory analysis 14 and changed a number by five times and didn't see much 15 compare on the results. So we were --
16 MEMBER REMPE: For each of those that you 17 didn't approve the process --
18 MR. HAIDER: I can remember at least four.
19 A couple of them we performed the confirmatory 20 analysis.
21 MEMBER REMPE: Okay.
22 MEMBER KIRCHNER: Maybe I can jump in 23 here. It seems to me, what they did was essentially 24 use nominal values expected for the NuScale power 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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26 module, and then exercise the methodology. And so, 1
what was really being approved here was the 2
methodology, the subchannel analysis methodology, not 3
the specific parameters.
4 I believe that and I expect we will see 5
that with Chapter 4 and 15. And then, it will be 6
incumbent on the applicant to demonstrate that these 7
are realistic and appropriate and, where necessary, to 8
back it up with experiment or independent analysis.
9 So, I think -- like, in one example, where 10 I think you used -- in relap five. And you did 11 demonstrate comparable, overall core delta Ps. Is 12 that correct?
13 MR. HAIDER: That's correct.
14 MEMBER KIRCHNER: So, that is an example 15 of an independent calculation to just demonstrate that 16 they're in the right ballpark.
17 MEMBER REMPE: Okay. So --
18 MR. HAIDER: And another example would be 19 that we're mixing parameter.
20 MEMBER KIRCHNER: Yeah.
21 MR. HAIDER: We're changing the parameter 22 by a factor of five.
23 MEMBER KIRCHNER: Right. When it comes to 24 things like the actual inlet flows and how much is 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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27 bypassed in the reflector, I think that is all to be 1
demonstrated in Chapter 4. Is that correct?
2 MEMBER REMPE: Okay. So, okay. So, the 3
criteria or condition three, is the applicant has to 4
provide justifications for modeling assumptions to 5
base flow models, heat transfer, and CHF correlations, 6
and plant-specific data, such as turbulent mixing 7
coefficients, et cetera, geometry notalization.
8 Sufficient information and justification 9
have to be provided. And you've said, yes, they've 10 met it. But yet, we didn't approve the value. We 11 didn't approve the process in some of these cases.
12 And that's where I'm kind of struggling 13 with is, is it enough or why didn't you say, well, 14 they gave us some things, but we're going to review it 15 carefully in Chapter 4 and 15?
16 CHAIRMAN CORRADINI:
I guess my 17 interpretation, Joy, is that, as Walt was saying, 18 these are nominal values. Given the nominal values, 19 the methodology's acceptable. But, it's essentially 20 on the applicant to show that the values used for the 21 design are appropriate and justified.
22 MEMBER REMPE: And how will the staff 23 decide that in Chapter 4 and 15?
24 MEMBER KIRCHNER: We do it for any 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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28 reactor.
1 MEMBER REMPE: With Chapter 4 of the 2
design certification and 15, will there be benchmark 3
calculations or will they just say, yeah, if the --
4 MEMBER KIRCHNER: It depends, at this 5
juncture. But it would be the same with any new 6
design. When Chapter 4 arrives, then you would have 7
to look for either experimental data or other basis to 8
justify something like the amount of bypass flow.
9 MEMBER REMPE: Okay. I --
10 MEMBER KIRCHNER: And if it can't be 11 justified, then one would expect that would be a 12 confirmatory item for a startup test, as an example.
13 MEMBER REMPE: Okay. I just -- I wanted 14 to -- I didn't see some of these things clearly in the 15 SE. And maybe that's just the way this is done 16 always. But, I was still kind of struggling with 17 well, it's approved, but they didn't approve a lot of 18 the underlying processes as well as the values.
19 MEMBER BROWN: But, I guess my way of 20 thinking about it, this is -- I would assume staff is 21 going to take the same approach they did for APR 1400.
22 MR. HAIDER: Yes.
23 MEMBER BROWN: Which, some things were 24 approved. Some things were left for confirmatory 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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29 testing for startup. So, I assume that's what staff's 1
going to do.
2 MR. HAIDER: Yes. That's precisely right.
3 And whatever we do not accept, approve, we also 4
documented that in the SER, so that it becomes a 5
reference for the Chapter 4 and Chapter 15.
6 MEMBER REMPE: So, yeah, we'll be looking 7
carefully at 4 and 15 to make that those values are 8
addressed.
9 MR. HAIDER: That's right.
10 MEMBER REMPE: And I, again, I think 11 that's just something we need to emphasize, okay?
12 Thanks.
13 MEMBER KIRCHNER: Mr. Chairman, since 14 there are no further questions from the committee, I 15 think we can turn to any members of the public for 16 comment. If there are any members of the public who 17 wish to make a comment, please do so. Just state your 18 name and your comment.
19 We're going to use the ten-second out 20 there. Okay. Again, if there are any members of the 21 public who wish to make a comment, please state your 22 name and make your comment. There appear to be none.
23 There appear to be none.
24 CHAIRMAN CORRADINI: We can close the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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30 line.
1 MEMBER KIRCHNER: We can close the line 2
then. So now, Mr. Chairman, the question is whether 3
members of the committee wish to go into closed 4
session and have any further detail questions that 5
might be of a proprietary nature?
6 CHAIRMAN CORRADINI: Anybody? I guess 7
not.
8 MEMBER KIRCHNER: So, therefore, I don't 9
think we need a closed session.
10 CHAIRMAN CORRADINI: Okay. Good.
11 MEMBER KIRCHNER: Thank you. I want to 12 thank the staff for a very complete and thorough 13 review of the applicant's submittal. Thank you.
14 CHAIRMAN CORRADINI: Okay. So, we're 15 going to adjourn this session. We will probably have 16 a read-through of the draft that the subcommittee put 17 together of the letter report. This would be a good 18 time to do that. So, staff can sit around for that if 19 you want, okay? Thank you very much.
20 So, we'll take a couple of minutes, only 21 a couple of minutes, to reconfigure so we can look at 22 the draft letter report from the subcommittee that 23 Walt has marshalled through the system. It's an open 24 session. You can listen to it.
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31 (Whereupon, the above-entitled matter went 1
off the record at 9:06 a.m. and reconvened at 10:12 2
a.m.)
3 CHAIRMAN CORRADINI: It must not have been 4
transmitted to us. That's good to know. Welcome, 5
Dennis.
6 MEMBER BLEY: Thank you.
7 CHAIRMAN CORRADINI: Are you in beautiful 8
Minnesota or beautiful New Mexico?
9 MEMBER BLEY: I'm still in New Mexico for 10 a little bit longer.
11 CHAIRMAN CORRADINI: Okay. We'll not 12 going to start for a couple of minutes. One other 13 business item, Dennis, did you get the phone number 14 for tomorrow's noon meeting?
15 MEMBER BLEY: I did. Thank you.
16 CHAIRMAN CORRADINI: Okay. And if you 17 have question, we can discuss offline. But, I'll be 18 there.
19 MEMBER BLEY: I got enough information 20 from Derek to clarify things.
21 CHAIRMAN CORRADINI: Okay. Good. Okay.
22 And we've got a line, so Derek can call in also.
23 MEMBER BLEY: I saw.
24 CHAIRMAN CORRADINI: Okay. All right. Do 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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32 we need to mute the NuScale line? We'll turn it on if 1
they call for lifeline. Otherwise, let's mute it. I 2
don't want to have that crackling during the meeting.
3 So, if the NuScale folks need to be called upon, 4
you're either going to alert your folks in the room 5
and we'll open the line, or we'll open the line to ask 6
you a question.
7 But, we're going to mute the NuScale 8
folks, just because of the background crackling.
9 Okay. We're ready to go. Okay. We're back in 10 session. And we're now going to take up the topic of 11 the DCD, Chapters 7 and 8, with open items. And am I 12 going to turn to Omid or somebody of major more 13 influence?
14 MR. TABATABAI: We're going to go to Shana 15 Helton.
16 CHAIRMAN CORRADINI: Oh, there she is.
17 I'm sorry.
18 MS. HELTON: Hello.
19 CHAIRMAN CORRADINI: Shana, go ahead.
20 MS. HELTON: Good morning. Thank you. I 21 don't know about the major more influence. I think 22 you've got all the influential people sitting in front 23 of you at the table today. But, I'll take the 24 pleasure of giving some opening remarks.
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33 CHAIRMAN CORRADINI: Okay. Good. Thank 1
you.
2 MS. HELTON: So, that you for that. So, 3
my name is Shana Helton. I'm the Acting Director of 4
the Division of Engineering and Infrastructure. And 5
sitting in front of you at the table today, you've got 6
Luis Betancourt and Dinesh Taneja. And they're from 7
the Instrumentation Controls and Electronics 8
Engineering Branch within my division in the Office 9
New Reactors.
10 So, we're very pleased to be here today.
11 It's a culmination of our safety evaluation with open 12 items. We'll give you a briefing and where we're at 13 with that, with the NuScale design certification 14 review. I think we've had a lot of good interactions 15 at the subcommittee level.
16 And that's helped influence what we're 17 presenting to you today. So hopefully, we'll cover 18 all the topics you want. And if not, I think we have 19 time on the agenda for questions. And with that, I'll 20 turn it on over. Thank you.
21 MR. TABATABAI: Thank you, Shana. Good 22 morning everyone. Good morning, Mr. Chairman. Thank 23 you very much for giving us this opportunity to 24 present to you the Chapter 7 instrumentation and 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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34 controls, as well as Chapter 8, electric power safety 1
evaluation report, prepared by the staff.
2 We presented these SERs to the 3
subcommittee back in June and also August of 2018. We 4
received comments. We tried to average those comments 5
in the revised SER. To my left and right, Luis 6
Betancourt and Dinesh Taneja, will be presenting 7
Chapter 7, instrumentation and controls.
8 And to my far right, Sheila Ray, is the 9
lead reviewer for electric power. And, based on the 10 agenda, we're going to start with Chapter 7. We just 11 want to remind the Committee, we don't have any open 12 items in the Chapter 7 SER, although we have, in a 13 couple of places, saying that we are waiting for 14 additional input from other branches to provide.
15 We have NuScale representatives in 16 attendance and -- as well as on the phone, in case 17 there are any more detailed questions that we need 18 their assistance. I will call upon them to provide 19 responses. Without further ado, I'll turn the 20 microphone to Luis Betancourt to start our 21 presentation of Chapter 7.
22 MR. BETANCOURT: Well, good morning. My 23 name is Luis Betancourt. I am the Acting Chief of the 24 Instrument and Controls Branch in the Office of New 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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35 Reactors. We're happy to be here today to talk about 1
Chapter 7. We have a lot of background in the slides.
2 So, I would like the members to look at the slides 3
nine and ten, even though we try to avoid the acronyms 4
as much as I can in the presentation.
5 This slide is basically to show the list 6
of the INC technical staff that participated in the 7
review. As part of the timeline from 2014 to 2016, we 8
actually had a lot of pre-application activities with 9
the applicant.
10 These three pre-application interactions 11 were so NuScale could actually embrace in the concepts 12 of the service which actually led to them using the 13 fundamental design principles to design the potential 14 platform as well as the NuScale architecture.
15 It also provided us a lot of time to 16 understand their design, as well as a lot of technical 17 issues that they were actually facing at that time.
18 In March of 2017, they submitted an application. And, 19 at that time, we already knew what are the areas that 20 we wanted to focus our attention, as far as the 21 review.
22 Around the same time, the ACRS glossary 23 approved the protection system platform topical report 24 that is compared by reference in the application. So, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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36 between March 2017 to December 2017, we actually held 1
five public meetings, each that contained 15 question.
2 And we were able to complete one audit 3
that actually contained the analysis, and also an 4
analysis for the system architecture, as well as the 5
diversity, a segmentation analysis technical basis.
6 Around January of 2018, we were able to complete the 7
draft SER with open items.
8 Even though it says, open items, we didn't 9
have any open items specifically on this SER. Open 10 items are referred to under chapter section 18 of the 11 application. So, when it came to March 2018, we were 12 able to receive the traditional assigned certification 13 and we were able to close all of the confirmatory 14 items in April 2018.
15 Two weeks ago, we were able to present to 16 the members at NCR subcommittee meeting and today we 17 are here at the spot of the full committee. I would 18 like to actually comment on both the staff and NuScale 19 as part of these interactions.
20 Because we had a lot of help and 21 collaborative involvement in being able to resolve all 22 of these issues. This is the first time to win a 23 critical path. So, for us, this was a good success 24 story on how to do a review, a dissected focus review.
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37 So the way that we actually established the review was 1
-- we call it a dissected focus review. You actually 2
have two approaches.
3 One was, that the office established a 4
policy of what they meant about having a safety focus 5
review, which lined up perfectly with the framework 6
that was in Chapter 7 or the review, specific standard 7
developed by the INC staff.
8 The use of insights to enhance a safety 9
focus review of the skill and design is consistent 10 with the fundamental design principles of 11 independence, redundancy, predictability, and 12 repeatability, otherwise known as determinism, 13 diversity, and simplicity.
14 This slide basically illustrates the way 15 that we actually performed the review. If you look on 16 your left, we started first with a tier one review, 17 where, in Sections 2.5 and 2.6 of the application, we 18 were able to review the design commitments and the 19 inspections test analysis on a circumspect theory, 20 otherwise known as I-Tech.
21 In the middle of the bin, that's where the 22 majority of the focus -- we spent on the time. You 23 will see the big bowl on the left. Basically, there 24 were three that were IBR and were incorporated by 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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38 reference, two technical reports, and one topical 1
report. The topical court is what led into high 2
interpretation.
3 Lot one that was already evaluated and 4
approved by the NCRS and its staff. As part of 5
technical review -- that contains 65, application-6 specific action items that were reviewed as part of 7
Chapter 7.
8 And in parallel, we were able to review 9
Chapter 9 and Chapter 14.35 on I-Tech and the 10 communication systems. And even though we're not 11 talking about that today and we're going to present 12 that at a later stage, that was also part of the 13 initial scope of the review.
14 On the left, we were able to have two 15 assumptions. The first one is about at worst. And 16 they'll have a slide that talks about that. And we 17 have also another TMI action item, 50.34, that even 18 though we're not the leap reviewer for that 19 assumption, we actually provided support.
20 And that evaluation is contained in 21 Chapter 8. Any questions? Okay. No questions is 22 good. So, as part of the atmos assumption, as I 23 mentioned before, this was evaluated and documented in 24 Chapter 7, with assistance of repair systems and the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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39 BRA. To give a brief history, NuScale requested an 1
assumption for the portion of the atmos rule requiring 2
diverse equipment to initiate a tubal trip on the 3
conditions indicative of an atmos.
4 They also stated that since a descent does 5
include an auxiliary or emergency free water systems, 6
that possibly the atmos rule requiring diverse and 7
problematic free water initiation system is not 8
applicable to them. Since they are relying the 9
purpose of the rule is to reduce the risk associated 10 with the atmos events.
11 The staff evaluated three major aspects of 12 this request. First, we evaluated how the design 13 reduced the risk of atmos redundancy, diversity, 14 independence, with the NuScale model protection 15 system. The built-in diversity of the model 16 protection system reduces the probability of a 17 familiar of scram.
18 Secondly, the staff evaluated how the 19 disarm responds to an atmos event and is actually 20 bonded by the disarm basis access analysis. And 21 finally, the staff evaluation showed that the MPS 22 designed resources and other contribution to the core 23 damage frequency, which is lower than the safety goal.
24 And 10 C.F.R. points us to rule-making documents.
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40 Therefore, the staff concluded that the on-the-line 1
purpose of the rule was met by the NuScale design.
2 I think this is where we're going to be 3
having a lot of questions. So, as part of the NCRS 4
subcommittee Chapter 7, we have over here summarized 5
at a high level the comments that we received. The 6
first one is basically about the configuration of the 7
data values.
8 And there was a concern that that 9
configuration was not specified in the application.
10 Our finding actually based that the application 11 clearly contains a design feature as a one-way 12 selection device from the model control system or the 13 plan control system to the plan network.
14 DCPO 2, Section 7.29 states that an 15 applicant must submit a cyber security plan in 16 compliance with 10 C.F.R. 573. Our review took credit 17 for this. But the compliance with the cyber security 18 program with the licenses responsible for implementing 19 the one-way data flow from the model control system or 20 the plan control system to the plan data network, 21 using hardware mechanisms.
22 This is clearly stated in Section B(1)(4) 23 of the directive 5.71. However, the applicant 24 recently submitted a letter. Through this, they 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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41 awarded the firewall connection that actually resolved 1
some of the software configuration issues that the 2
NCRS was talking about at the last meeting.
3 And they committed to use an isolation 4
device that, in their words, is basically enforcing 5
the harbor mechanisms.
6 CHAIRMAN CORRADINI: Say the last part 7
again, please?
8 MR. BETANCOURT: Oh, the last one?
9 CHAIRMAN CORRADINI: Yeah. The last part 10 you said, they committed to what?
11 MR. BETANCOURT: They committed to us in 12 the letter that was actually submitted to us on 13 September 14. I don't know if you guys have seen that 14 or not. Okay. So, in the letter, they actually 15 submitted revised language that they removed the 16 firewall language that a lot of members have some 17 trouble.
18 MEMBER BROWN: Which firewall are you 19 talking about, the one from the plant network out to 20 the rest of the world? That's where the firewall is 21 specified.
22 MR. BETANCOURT: Right.
23 MEMBER BROWN: The only place a -- that's 24 the only one. All the rest of the PCS and the MCS 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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42 communications were via this unit directional data, 1
but it never mentioned the word firewall. That was in 2
you all's SER where you called it that, which was an 3
inconsistency.
4 MR. BETANCOURT: It was also --
5 MEMBER BROWN: Let me finish.
6 MR. BETANCOURT: Right.
7 MEMBER BROWN: So, when you talk about 8
firewall, you're going to have to differentiate. The 9
only firewall that they had in their Chapter 7 and --
10 was from the plant network to the rest of the business 11 network and all the rest of the -- the entire world 12 can talk to this business network or whatever, okay?
13 MR. BETANCOURT: Right. And that's 14 consistent. So --
15 MEMBER BROWN: So, if that's the software, 16 whatever it is, that's where the cyber security 17 controls are most critical.
18 MR. BETANCOURT: Right.
19 MEMBER BROWN: To relate or make the 20 MCS/PCS a part of this cyber security, that's an 21 implant communication
- device, not an ex-plant 22 communication device.
23 MR. BETANCOURT: Right.
24 MEMBER BROWN: So, to put that together 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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43 with this secure development environment in a cyber 1
security plan is, to use a cumbersome word, absurd, 2
okay? And there's no way that we should be dependent 3
on that communication process implant.
4 MR. BETANCOURT: Right.
5 MEMBER BROWN: It ought to be similar to 6
what we do from the main -- you know, the mocking 7
protection system and the PPS, which are very explicit 8
in how those communication modules -- you look at the 9
Chapter 7, it states very explicitly that those are 10 one way and they tell you how.
11 MR. BETANCOURT: Right.
12 MEMBER BROWN: They're only to transmit 13 wire for those equipment or EEE devices or whatever 14 they end up using, is the only one connected. So, 15 there is actually a physical hardware limit on how 16 those could be accomplished.
17 MR. BETANCOURT: Right.
18 MEMBER BROWN: And yet, here in the most 19 vulnerable section of the communications, all the 20 plant control systems, both all 12 module control 21 systems, including the overall plant control system, 22 is just connected through this nebulous isolation 23 device, which can be, based on their comments in the 24 subcommittee meeting, could be whatever they determine 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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44 they want it to be in five years.
1 MR. BETANCOURT: Right.
2 MEMBER BROWN: So, that, to me -- this is 3
to me. This is me speaking, right? This is not the 4
committee speaking. That's me speaking.
5 MR. BETANCOURT: Right.
6 MEMBER BROWN: Does not make any sense.
7 Largely because you have to separate the implant 8
communications from the explant communications.
9 MR. BETANCOURT: Right.
10 MEMBER BROWN: I have no problem with the 11 firewall. Obviously, that one's going to be a cyber 12 security plant, you know, up in the plant network, out 13 to the world.
14 MR. BETANCOURT: Right.
15 MEMBER BROWN: That's going to be what it 16 is. But, we need a door from PCS and MCS to that 17 plant. Right now, there's no door specified. It's an 18 open door.
19 MR. BETANCOURT: Okay.
20 MEMBER BROWN: Keep in mind that that's my 21 considerations or my thoughts, which I will be 22 obviously recommending to the committee to either 23 agree or disagree with.
24 MR. BETANCOURT: Right.
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45 MEMBER BROWN: But, that's the position 1
I'm coming from in terms of how I review, post their 2
review.
3 MR. TABATABAI: So, Member Brown, Actos, 4
in technical reviewing this document, there were a 5
couple of elements that played the rule and the way we 6
reviewed it. You know, the safety focus review 7
explicitly stated -- and I will review, we need to 8
take credit for operational programs. Okay?
9 So, in Chapter 13, where the operational 10 programs are laid out, there is a CRL item for the 11 serial applicant to submit a cyber security plan, 12 okay? That is an operational program. So, we are 13 taking credit for that as one of the items that has to 14 occur in accordance with part 73, the cyber security 15 program.
16 And in Chapter 7, there are explicit 17 statements made for the cyber security plan to be 18 developed in accordance with part 73. So, recognizing 19 that, and then we go to 5.71, and 5.708 specifically 20 states that preventing encrypted data from bypassing 21 checking mechanism -- it's implementing one-way data 22 flows using hardware mechanism. So, it really 23 provides guidance on how to develop a cyber security 24 plan, for the given facility. So it is a problematic 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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46 item. And looking at the operational programs and 1
looking at that safety focus review, we are taking 2
credit in our review of the operational program.
3 That was the approach that the staff used 4
in looking at this realistically. And recently, we 5
had to see we had received a direction from our Office 6
Director which basically says, how do you approach a 7
review which provides a reasonable assurance of 8
safety.
9 And one of the guidance that we received 10 from -- I would say, a direction that we received from 11 our Office Director, it was to really, you know, take 12 credit for operational programs in this as well. So, 13 there's a couple of places.
14 I mean, I can quote the memo that we got 15 from our Office Director, Fred Brown, that basically 16 says, "Doing in-depth review of parts of the design 17 certification application that requires site-specific 18 parameters or values may not be necessary or efficient 19 when there is no concurrent review of the combined 20 license or early site permit application that 21 references the design." I had no idea what that meant 22 either.
23 CHAIRMAN CORRADINI: So, can I ask a much 24 more uneducated question?
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47 MR. TABATABAI: Sure.
1 CHAIRMAN CORRADINI: The way I view 2
Charlie's comment, at this point, his comment, is you 3
guys are doing it -- you guys -- the NuScale design is 4
suggesting a way to handle it within the -- I'll get 5
these wrong I think -- the MCS and PCS.
6 Oh, I'm sorry. Within the -- within a 7
certain part of plant. And yet, in this part of the 8
plant, they've chosen an unspecified approach. Why 9
not simply adopt the same approach for all in-plant 10 communication? That, I think, is the essence of 11 Charlie's --
12 MEMBER BROWN: Well, okay. So, I have an 13 answer for that.
14 CHAIRMAN CORRADINI: Is that close to 15 being accurately, Charlie?
16 MEMBER BROWN: Relatively. I mean, the --
17 right now, when you look at MPS, PPS -- that's the 18 plant protection system and the module protection 19 system, which is reactor-tripped and safeguards, I 20 mean, the hardware is a hardware. And it's very, very 21 explicit in Chapter 7 as to how it's accomplished.
22 CHAIRMAN CORRADINI: And so, my question 23 is -- I interpret Charlie's comment to be, so why not 24 just be that explicit and that simple for the other 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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48 one?
1 MR. TABATABAI: Okay. Explicitly, it's 2
there. So, this dial which presents a check-valve, 3
essentially is a one-way communication. Now, what is 4
missing at this stage of the application is the 5
specification of this device, okay? Exactly, you 6
know, what parameters and what specification.
7 So, those are really part of the, you 8
know, as-built configuration when the plant is built.
9 And so, there is that operational program that really 10 requires the, you know, the critical digital access to 11 be specifically identified that have to comply with, 12 you know?
13 And read that 5.7 was very explicit on 14 that as to what one of the inequalities or the 15 characteristic of the diode has to be. So, from our 16 point of view at this review, we are looking at that 17 data buyer and saying, okay, it's typically one-way 18 communication.
And it will not allow any 19 communication coming back into the network.
20 MEMBER BROWN: But, hold it, just a 21 minute.
22 MR. TABATABAI: Right.
23 MEMBER BROWN: To quote the NuScale 24 representative in subcommittee, he stated, we will 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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49 specify that in our application, if it is digital or 1
hardware or software-based. In other words, software-2 based is just fine in the -- put aside all the other 3
blathering about 5.71 and other type things. They 4
explicitly stated that this would allow a software-5 based data diode, which a software --
6 MR. TABATABAI: Okay. I just --
7 MEMBER BROWN: Let me finish.
8 MR. TABATABAI: I'm sorry.
9 MEMBER BROWN: Which a software-based data 10 diode, when it's controlled and configured that --
11 very explicit ways they're operating, can't be 12 compromised, as opposed to a hardware, one-way diode.
13 And, right now, that's not clear, regardless if you go 14 through all these other steps because red guide 5.7 15 talks about the one-day data diode being a hardware-16 based that doesn't require --
17 MEMBER KIRCHNER: It's a guidance.
18 MEMBER BROWN: It's a guidance issue, not 19 an explicit. It says, you've got to think about it.
20 That's all it does. I mean, I was there. I wrote the 21 letter on 5.71 ten years ago. So -- or eight years 22 ago, whatever it was, back in 2010, I think.
23 MR. TANEJA: So, it's an operational 24 program that has a, you know, a regulatory framework 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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50 which really flowers. And, you know, where they are 1
actually looking all the, you know, these critical 2
data flows and, you know, whether or how they are 3
protected.
4 So, you know, so the NRC -- so the reason 5
we understand this to be an operational program is 6
that cyber security is an evolving threat. Now, what 7
today we consider secure, you know, five, ten years 8
from now, may be, you know, somebody's probably -- a 9
thief is going to figure out how to break that lock.
10 So, you know, so what is the security at 11 that time? That's why I guess it is really, you know, 12 an evolving stage where the program has to also be 13 evolving. So, what is the requirement at the it's 14 going to take place? And that's the way staff is 15 looking at this thing.
16 MEMBER BROWN: Dinesh, I don't understand 17 18 MR. TANEJA: Yes.
19 MEMBER BROWN: How we can say we're going 20 to evolve --
21 CHAIRMAN CORRADINI: I mean, if the 22 applicant wants to make a comment, that might help 23 you.
24 MEMBER BROWN: I hope. But, my heart is 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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51 not jumping with joy or apprehension that it's going 1
to be anything like we would expect. Before he makes 2
a comment, I would -- I'd just -- you're not -- don't 3
leave. I just want to make one observation.
4 Every other applicant that we've come 5
through have committed to make that off, outside the 6
plant, communication from in-plant stuff, a hardware-7 based, data diode, explicitly. This is the only 8
applicant that has come through saying, we can accept, 9
and we're smart enough to be able to design it however 10 we want to design it in five years.
11 And it's all going to come out okay.
12 Trust us. And, quite frankly, the evolving nature of 13 the ability of people to satisfy cyber requirements 14 with software-based protocols that you have to 15 monitor, check for threats, upgrade constantly, is 16 always in reaction to being compromised.
17 MR. TANEJA: Yes. I understand.
18 MEMBER BROWN: Never, in terms of being 19 able to prevent. And all you've got to do is -- you 20 hear the news every day. So, that's the reason I'm as 21 hard over as I am. And hopefully, I can convince my 22 folks. Now I will let -- excuse me, for letting me 23 blather on here before you go.
24 MR. ARNHOLT: No. Thank you. This is 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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52 Brian Arnholt, the INC Supervisor with NuScale Power.
1 At the subcommittee meeting, we did take back the 2
recommendations from the subcommittee members. And we 3
made a specific, explicit change in our FSAR to refer 4
to these diodes as one-way, deterministic isolation 5
devices.
6 MEMBER BROWN: Nope. It says -- it 7
doesn't say one-way. It says, deterministic isolation 8
device, which -- whatever that means. An RS-232 with 9
only one line going out can be defined as a 10 deterministic isolation device. But, it's not totally 11 software-based. I mean, it's not totally hardware-12 based. Excuse me. Go ahead.
13 MR. ARNHOLT: Right. And I'm continuing.
14 Where that language came from, it came from NEI-13-10, 15 Revision 6, that was issued in 2017. It has received 16 endorsement by the NRC staff. And we did contact 17 several industry representatives to gather 18 understandings about what is an industry best practice 19 today.
20 And you're exactly right. Hardware-based 21 devices are an industry best practice. We've actually 22 contacted some vendor, and met vendors who supply 23 hardware -- what they call hardware-based devices.
24 There is actually software on either end of those 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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53 hardware devices that functions.
1 So, we were very -- that's why we were 2
very deliberate in the language we used. Now, with 3
that said -- and I'll enter for the record what a one-4 way deterministic isolation device is. It refers to 5
a boundary control device that transmits or receives 6
network traffic in one direction only, which is 7
enforced in the hardware design, not software.
8 No software configuration or 9
misconfiguration will cause the boundary device to 10 reverse the direction of data flow or become a two-way 11 device. And in NEI-1310, they actually use, for 12 example, the data diode. So, we removed any 13 connotations that that device is configured or 14 operates on a software leg.
15 MEMBER BROWN: Are those words in Chapter 16 7 or are they just in this NEI document?
17 MR. ARNHOLT: There's a description in the 18 NEI document. But, in Chapter 7, we call it a one-19 way, deterministic isolation device.
20 MEMBER BROWN: So, let me go backwards.
21 The nice words you just talked about, you put those in 22 Chapter 7, it may look acceptable once we see how 23 they're -- but, right now, just saying deterministic 24 isolation device is vague.
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54 MR. ARNHOLT: Right. And to add to what 1
the NRC staff said about leveraging operational 2
programs, why we chose that language, because that is 3
an endorsed guidance that the current operating fleet 4
is using today.
5 So, we took that approach to set up future 6
CLL applicants, when they actually implement the cyber 7
security provisions of their -- of the design when it 8
meets the plan, to leverage what we put into our DCA.
9 That was our intention.
10 MEMBER BROWN: Well, the role of is to try 11 to ensure that we maintain a satisfactory safety 12 posture, okay? That is defined in advance and doesn't 13 "evolve in some later determination" because industry 14 evolves as they go. In other words, we need somewhat 15 well-defined, explicit statement of what is meant.
16 And, right now, that's not in Chapter 7. It's 17 fundamentally the difficulty.
18 CHAIRMAN CORRADINI: I think we're clear 19 now.
20 MEMBER BROWN: There's enough words now in 21 the transcript that that ought to be clear. It's just 22 the -- once we went to the deterministic isolation 23 device, that was even, in my opinion again, was more 24 vague and ambiguous than a uni-directional data diode.
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55 That at least has, in the context of going and looking 1
at products, has some context.
2 The way that was phrased does not. Now, 3
your additional words that you talked about, if they 4
were put together as such that it is very, very clear 5
that these devices -- whatever hardware. I'm not 6
worried about base stuff.
7 But, they are configured based on a 8
physical configuration of transmit and/or receive that 9
you cannot change by entering it with some code 10 somewhere else on the device, in the device, or 11 attached to the device through some other, you know, 12 like a laptop or whatever. It ought to be a hardware 13 configuration.
14 And once there, it can't be changed, 15 unless you go in and take the device out and 16 physically do something to it. And that's the thought 17 process. And that sounds like what you were talking 18 about, but it's just not in Chapter 7 right now.
19 MEMBER RAY: Mike, can I make a comment?
20 Are you done, Charlie, for the moment?
21 MEMBER BROWN: Yeah. At the moment, for 22 a moment. Am I ever done?
23 MEMBER RAY: I just wanted to make a 24 comment to the members. This is a very specific and 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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56 detailed example of a general issue. The staff 1
mentioned taking credit for operational programs to 2
which guidance exists and applies.
3 But, it does illustrate the process in 4
which we're engaged now, but not later when this 5
operational guidance, the red guide, is applied to an 6
operational program. And we need to reflect on that.
7 Charlie's trying to pursue something very specific 8
that he's very interested in right now.
9 But, the essence of it will be that this 10 credit that was referred to, is part of what we're 11 reviewing. It's credit for guidance that will be 12 applied to an operational program in the future. And 13 we -- op review will be ancient history by then. So, 14 I just want to make that point because we'll be 15 talking about the generic aspects of the enhanced 16 safety focus review approach at another time.
17 MS. HELTON: Is it okay if I pipe in just 18 for a second? This is Shana Helton. On that topic, 19 I think the staff has a strong sensitivity to what 20 you're raising about what type of review we're doing 21 now with the design certification and what type of 22 review we'd be doing later, as part of the COL review, 23 if and when one were to come. So, I think part of 24 what we want to do -- there's the combination of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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57 products that will be referred to at the COL phase.
1 Our staff safety evaluation is one of them.
2 And we're trying to be very clear about 3
what would -- you know, why is it acceptable today, as 4
a design serve? What needs to be evaluated as a COL 5
item? I think we could say that we would be very 6
specific in our SE writeup about the COL item that 7
would have to be associated with this. Especially, 8
with regards to the security plan.
9 MEMBER RAY: Well, I think that's an 10 interesting point. And it illustrates the dialogue 11 that I don't know has fully taken place on this point.
12 In other words, things that we would ordinarily expect 13 to resolve at this time, as Charlie was pursuing, 14 you'll have another chance to see what the resolution 15 is of the COL.
16 The understanding of that -- and having 17 confidence in it is something that I don't think all 18 of, at this point in time, are satisfied with. And 19 yet, things are moving on and we need to find out how 20 we can get a better understanding.
21 MEMBER BROWN: My point is, on the COL end 22 of the thing, the only way the COL knows, on an 23 explicit basis, what is desired, is through the DCD, 24 where it's explicitly specified. Right now, the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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58 condition is not specified. So, he is up -- it's up 1
on the air.
2 Five years from now, oh, I'll do it this 3
way. And therefore, I've got these wonderful guides 4
and we've got all these marvelous cyber security 5
programs and this is going to serve us well. So, he 6
doesn't know. Unless we tell him in the DCD where we 7
want that hard wall for safety purposes.
8 Access to those plant control systems can 9
put you into -- they can take over control of the 10 plant. They can initiate every item in there and 11 create an unknown, unknown plant conditions, that your 12 protection system will not protect against.
13 And if you think you can protect that with 14 some vague reference to something that'll be done by 15 the COL years later, is -- I just can't even 16 comprehend that because that -- it's an unknown, 17 unknown. And it is a combination of events that we 18 don't analyze for, that -- our whole analysis is very 19 explicit in terms of what you have to look at.
20 And, I mean, it's like the atlas. We've 21 determined in this circumstance, they don't have to 22 comply with that. And we didn't take issue with that 23 in our meeting because of the -- I think it was the 24 analysis basis puts it outside the boundary conditions 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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59 where we should have to consider that. That's a risk-1 informed type decision.
2 So, we have not -- we haven't really 3
addressed it in Chapter -- I guess it will come up in 4
Chapter 15 at some point. Is that correct? So, we'll 5
hear that one again. But, the DCD is the only place 6
that the COL has for reference, what is really 7
desired.
8 And this is a major vulnerability. If 9
you've got anything that's -- any doorway that's 10 controlled by software is like giving a hacker a super 11 highway into every -- and once he gets into this 12 distributed control system, there are no boundaries.
13 This is the first of the -- I'm not aware of any other 14 total distributed control system that we've looked at 15 in the other apps.
16 They've all been explicit systems for each 17 and every component or system. That's not the case 18 here. Now, they're all bundled together, even though 19 it's segmented. I may be finished. I don't know.
20 You can tell I'm over this.
21 MEMBER RAY: I just want to concur with 22 Charlie so he's not alone. I think that should be a 23 condition. If it's not called out now, then it should 24 be added as a condition.
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60 MR. ARNHOLT: It may show up in our 1
letter.
2 MEMBER RAY: Or just -- I'm going to 3
approach this an example. It's an example. It's a 4
real good example, but it's just an example.
5 MEMBER BROWN: Yeah. It's an example of 6
something where we don't have total -- you look at the 7
operational approach to that and it may not meet what 8
we want later. That's all. And Harold's point was 9
valid.
10 MALE PARTICIPANT: Member Brown, thank you 11 very much for elaborating on this issue. So, I think, 12 based on what NuScale's representative explained and 13 the staff's review of additional information, I 14 believe we have some additional clarification to make 15 in Chapter 7, FSAR, final safety analysis report, as 16 well as if there are any needs for our SER to be -- so 17 18 CHAIRMAN CORRADINI: So, I think we need 19 to move on. But, from a process standpoint, we're 20 going to go with what we know is written. And we kind 21 of know where some suggestions are by certain members.
22 MALE PARTICIPANT: And we will review your 23 letter to make those quantifications.
24 MR. BETANCOURT: Anything else or -- no?
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61 I'm looking at the boss. So, the second comment that 1
we got off here was about the motor control system and 2
the plant control system technical analysis. And I 3
believe the concern was that the SER implied that a 4
failure of these systems could affect the motor 5
protection system or the plant protective system.
6 So, the SER was clarified that a failure 7
of these systems does not affect the safety function 8
rather than the motor control -- motor protection 9
system or the plant protection system. The third 10 question was related to the plant impacts associated 11 with true post-related failure.
12 So, RCS flow sensors -- and I think there 13 was a comment. And the way that we clarified that in 14 the SER was that the RCS low-flow protection actions 15 are not credited in any design bases, accidents or 16 transients.
17 Hence, the -- on the liability of the RCS 18 flow variable, it's not a safety concern. So, I don't 19 know if that addresses your question or not.
20 MEMBER RAY: Thank you. That does.
21 MEMBER BROWN: One comment on the 22 segmentation thing. I think you included that in that 23 revised of the SER.
24 MR. BETANCOURT: Right.
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62 MEMBER BROWN: And I think I remember 1
reading it. My question was -- my comment was, you 2
all made the statement that the segmentation was 3
necessary to prevent --
4 MR. BETANCOURT: The first impact to the 5
motor protection system.
6 MEMBER BROWN: Yeah. In other words, it 7
-- somehow it could go backwards and affect that.
8 MR. BETANCOURT: Right.
9 MEMBER BROWN: And I guess the thought 10 was, you really needed to disconnect that thought 11 because it really can't. It's a one-way communication 12 and it can't go backwards.
13 The issue, to make sure I understand it, 14 was you didn't want compounding failures within the 15 control systems to result in a situation where the 16 module protection system could not perform its 17 function in accordance with the safety analysis. Does 18 that -- did I phrase that right or --
19 MR. BETANCOURT: Yeah.
20 MEMBER BROWN: And I don't remember your 21 exact words. But, I just wanted to make sure here --
22 now, I've got in the record, that I can remember it, 23 how I understood it when I read it. I'm trying to 24 clarify that for the members here so they'll have some 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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63 idea of what we -- what I was talking about.
1 MR. BETANCOURT: So, that was an oversight 2
on our part. So, we've corrected that in the rest.
3 MEMBER BROWN: All right. Yeah. I 4
thought you did. I didn't have any question when I 5
read the revised SER.
6 MR. BETANCOURT: And the last comment was 7
basically that we got a lot of the open items that 8
were specific to Chapter 7. We removed that language 9
from the SER, as well as some editorial changes that 10 we saw.
11 We also included three new confirmatory 12 items -- so, new letters that we received in July and 13 the recent letter that the applicant submitted in 14 September. That's actually now incorporated in the 15 staff evaluation report.
16 MEMBER BROWN: Was that relevant to the 17 SDOE-type stuff in those various paragraphs?
18 MR. BETANCOURT: Yeah. Right.
19 MEMBER BROWN: But, if those change based 20 on what we're doing -- I just don't like the idea.
21 I'm uncomfortably with coupling X-plans, programs, if 22 I haven't phrased this properly earlier, with -- and 23 I've tried to stay out of those. I totally understand 24 what goes on relative to the plant network out to the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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64 world. But, once we're in-plant, those communications 1
ought to be solid, relative to their either receive or 2
transmit or both.
3 And the 57.0-1, is explicit and shows 4
those fairly clearly. So, it allows us to look at 5
that, as well as the other unidirectional, as well, as 6
you specified, the bi-directional. And you can see 7
where, you know, where you might have a problem or 8
don't.
9 MR. BETANCOURT: Right.
10 MEMBER BROWN: So, that's -- now, had you 11 all did -- let me ask one other question. You all 12 made one other discussion relative to the MCS 13 compromising the MPS. The same issue would apply to 14 the PCS compromising the PPS, the plant protection 15 system.
16 MR. BETANCOURT: Right.
17 MEMBER BROWN: I've assumed, based on the 18 review of those communications that your analysis for 19 MCS backwards to MPS, would also apply and show your 20 satisfactory from PCS back to the P -- and I may 21 explicitly state that in the letter just to make sure 22 we have that on the record.
23 MR. BETANCOURT: And we were able to 24 revise that in the SER.
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65 MEMBER BROWN: The last one?
1 MR. BETANCOURT: Look, in the version that 2
we sent you earlier in the week, that was revised.
3 MEMBER BROWN: I couldn't find that. I 4
looked explicitly for the same words that you applied 5
for the MPS/MCS issue. I didn't -- I could not find 6
it for the PCS.
7 MR. BETANCOURT: Okay.
8 MEMBER BROWN: So, if you can tell me what 9
page of the SER that's on, I would appreciate that --
10 the revised SER.
11 MR. BETANCOURT: Okay.
12 MEMBER BROWN: Okay. That's all I had, 13 Mike.
14 MR.
BETANCOURT:
So, let's go to 15 conclusions. So, to conclude the approach that the 16 staff used for the precise specific review standard 17 for Chapter 7, resulting in a single architecture and 18 the high system design we compared the fundamental 19 principles and this resulted in the completion of the 20 safety evaluation in an efficient and effective focus 21 matter.
22 And the staff concludes that the design to 23 be saved on the compliance with applicable 24 regulations. Any more questions before I transition 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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66 the presentation to Sheila? Okay.
1 MS. RAY: Good morning. My name is Sheila 2
Ray. I'm in NRR. My division is Engineering, the 3
electrical engineering and new reactors license 4
renewal branch.
5 MEMBER BLEY: Can I interrupt? This is 6
7 CHAIRMAN CORRADINI: Dennis, go ahead.
8 MEMBER BLEY: Yes, Sheila, I want to ask 9
you a question that you can answer as you go through 10 the presentation. But, as I looked through your 11 slides, you're going to talk about the remaining two 12 open items.
13 One of them relates to exemptions on DDC-14 17 and 18. But, the SER we reviewed and I believe 15 during our subcommittee, there were also exemptions on 16 33, 34, 35, 38, 41 and 44, that were still under 17 review. Tell us about those and if those have been 18 closed.
19 Because they were not in -- they were not 20 closed in the version we read. And my last thing is 21 related to the Chapter 7. I just want a second to 22 thank Charlie for staying on the one-way 23 communication. That's all for me.
24 CHAIRMAN CORRADINI: Do you have, Sheila, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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67 what he's got?
1 MS. RAY: Yes.
2 CHAIRMAN CORRADINI: And so, just bring it 3
up when it's appropriate, when you get to your 4
exemption discussion, if you could.
5 MS. RAY: Sure.
6 CHAIRMAN CORRADINI: Thank you.
7 MS. RAY: Well, on slide two, I just 8
wanted to mention we have a lot of reviewers for this 9
Chapter and we appreciate their assistance. So, our 10 SER is based on rev zero of the DCA. in phase 4, we 11 will address the revisions from rev one of the DCA.
12 Our SER contains two major open items and 13 we'll be discussing those. And our open-end 14 confirmatory items will be closed in phase four of our 15 review. So, on the -- regarding the NuScale design, 16 the electric power system for the NuScale design is 17 comprised of non-safety-related AC and non-safety-18 related DC power systems.
19 The design does not depend on off-site or 20 on-site AC electrical power systems, including that 21 from the transmission grid for safe operation. The 22 non-safety AC systems are comprised of low, medium, 23 and high-voltage systems, as well as backup diesel 24 generators and auxiliary AC power sources. The on-25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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68 site DC systems include the highly reliable EDSS and 1
EDNS systems, both non-class one. Next slide.
2 Using the DSRS or SRP, as well as the 3
graded review approach, the staff reviewed the design 4
of the electric power systems necessary for the safe 5
design and operation of the plant or whose failure 6
might adversely affect their safety-related or risk-7 significant functions.
8 There are two major open items, one 9
pertaining to the GDC 17, 18 exemptions and one on the 10 electrical penetration assemblies. At this point, I 11 will address Member Bley's comment on GDCs 34, 35, et 12 cetera. Those are still remaining as open items at 13 this point.
14 They are related to GDC 17 and 18. We 15 will have more discussion with our Chapter 15 16 colleagues and continuing reviewing that in phase 17 four. Does that address your comment or question?
18 MEMBER BLEY: Let me get unmuted. Yes, it 19 does. Thank you. I appreciate that.
20 MS. RAY: No problem. Next slide. So, 21 this open item on the exemptions is recurring 22 throughout Chapter 8, in that this open is referenced 23 in Section 8.2 for off-site power systems, Section 24 8.31 for on-site AC systems, Section 8.32 for on-site 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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69 DC systems, and Section 8.4 for station blackout.
1 Basically, this particular open item is repeated in 2
each section of Chapter 8.
3 The NuScale design does not rely on 4
safety-related AC or DC power systems. A topical 5
report was submitted on the safety classification of 6
passive nuclear power plant electrical systems. And 7
the staff approved the TR with five additional 8
conditions.
9 The open item relates to the exemptions to 10 GDC 17 and 18, as described in DCA, Part 7, regarding 11 the staff verifying that the design does not require 12 safety-related power. In addition, the Chapter 15 13 review on accident analyses is still ongoing.
14 The staff issued an REI regarding how the 15 NuScale design meets the conditions of applicability 16 and the five, additional conditions. The staff is 17 currently evaluating the response as part of the 18 Chapter 8 and 15 review.
19 MEMBER MOORE: So, just to make sure I get 20 it, so this is connected to the major open item 21 relative to how the TR is met by the actual design?
22 MS. RAY: Correct.
23 MEMBER MOORE: And we will see that in 24 phase later?
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70 MS. RAY: Yes. When we come back, 1
completing our phase four SER, and we come to ACRS in 2
phase five.
3 MEMBER MOORE: So, let me ask a somewhat 4
unsophisticated question. Since the TR was written by 5
NuScale and their design supposedly meets it, is there 6
some substantive reason for the delay? I would expect 7
this would be clear. What am I missing?
8 MS. RAY: So --
9 MEMBER MOORE: Can you give me a hint as 10 to why it's not closed at this point? Is the design 11 being modified to meet it? I'm still struggling here.
12 MS. RAY: The staff wasn't clear on how 13 the NuScale design does meet all of the conditions of 14 applicability. And some of those are related to other 15 chapters. So, until the other chapters are more 16 complete, we cannot make our conclusion in Chapter 8.
17 MEMBER MOORE: Okay. So, what you're 18 saying is, there are system interactions that have yet 19 to be determined for transients, accidents, et cetera, 20 et cetera?
21 MS. RAY: That's correct.
22 MEMBER MOORE: Okay. Fine. So, let me 23 ask another one. So, until we see Chapter 15 and it's 24 closed, 8 may never be closed? The open item in 8 may 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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71 never be closed.
1 MS. RAY: That is correct.
2 MEMBER MOORE: Okay. Fine. Just 3
checking. But, and last --
4 MS. RAY: Yes.
5 MEMBER MOORE: That then kind of returns 6
back to the Chapter 7, because all of these 7
assumptions are hooked together. Because the only 8
open items that I saw in Chapter 7, were essentially 9
those pointing to 8.
10 MS. RAY: Chapter 7, I don't believe, has 11 any open items.
12 MEMBER MOORE: Well, there was reference.
13 Well, then maybe I am --
14 MR. TANEJA: I didn't see any specific 15 open items.
16 MEMBER MOORE: Okay. Excuse me.
17 MR. TANEJA: But, there are open items 18 that reference Chapter 8 and 15.
19 MEMBER MOORE: Correct. That's my -- that 20 was my point. Okay. Thank you. I'm just trying to 21 refresh my memory.
22 MS. RAY: I understand. Next slide, slide 23 seven. The second open item is regarding electrical 24 penetration assemblies. And the staff issued an RAI 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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72 regarding the non-Class 1-E, electrical penetration 1
assemblies and their respective productive devices.
2 The applicant indicated that the non-Class 3
1-E EPAs have no electrical circuits that use the 4
associated containment penetration to perform a 5
safety-related function and that the EPAs designed as 6
non-Class 1-E are subject to the same EQ and seismic 7
requirements as Class 1 EPAs.
8 Furthermore, the applicant provided 9
clarity on the self-limiting protective devices, such 10 that the maximum fault current in these circuits would 11 not damage the penetration if the current was 12 available indefinitely. The staff finds the response 13 acceptable, since the non-Class 1-E EPAs will not be 14 impacted by a fault and are subject to the same EQ and 15 seismic requirements as Class 1 EPAs.
16 Currently, as a confirmatory item in the 17 draft, phase four, SER. And just for a conclusion, we 18 are working on our phase four review and these are the 19 two open items. So, at this time, I'll take any 20 questions.
21 MEMBER MOORE: I'm back to -- as the 22 official, designated worrier, I'm still -- this is 23 probably not -- let me state my concern, and then, 24 maybe this is not the forum to discuss it, but you'll 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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73 take it back to the higher-ups.
1 MS. RAY: Yes.
2 MEMBER MOORE: I'm trying to understand, 3
in a logical fashion, if all of these things are 4
connected, which is the first logical thing to look at 5
in phase four, so the other bubbles start falling? In 6
other words, is Chapter 15's accident analysis the 7
key? It strikes me, that's the key.
8 That is, I want to show in my simple mind 9
that the sourcer is X and when I apply the sourcer of 10 design-basis accidents, we've satisfied it. The 11 accident analysis shows that I keep the core cool and 12 I can, essentially, get the ultimate heat sync.
13 Once I satisfy all of that, all of these 14 other things are going to meet. So, am I right in 15 that simple-minded thought process?
16 MS. RAY: I guess I would --
17 MALE PARTICIPANT: Mr. Chairman, I'd like 18 to make a comment on that. You're absolutely right.
19 We all are actually making adjustments to our 20 schedules for phase four review and before we come to 21 the ACRs to present our phase fours reviews.
22 So, we are taking into account what 23 portions of, for instance, Chapter 8 requires input 24 from Chapter 15, so we can schedule those 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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74 presentations in tandem so there is a full picture to 1
be presented to the ACR.
2 CHAIRMAN CORRADINI: Okay. And the reason 3
I'm -- and I figured you'd tell me that. But, so --
4 my concern kind of revolves around this. I think, 5
when the time has come, the committee members are 6
going to want to look at this carefully.
7 And therefore, if somehow, all of a 8
sudden, the schedule starts slipping, so be it. Just 9
so we're clear two years in advance and there's no 10 surprises. Okay. I've said it.
11 MALE PARTICIPANT: We understand the 12 comment.
13 CHAIRMAN CORRADINI: Okay. Thank you.
14 Are you guys done?
15 MS. RAY: Yes.
16 CHAIRMAN CORRADINI: Dennis, did you have 17 any more -- you wanted to be online to make sure you 18 had your questions asked.
19 MEMBER BLEY: I did. And my questions are 20 all pretty well answered. I want to follow-up on what 21 Mike just went through. And I think when it comes 22 time to close this out, we need to have real clarity 23 on all the conditions in tables 3.1 and 3.2 of the 24 topical are met and especially how the staff has 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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75 concluded that all of their conditions have been met 1
as well. I'm sure that'll be in that phase four SER.
2 But, we will be looking closely at that. And that's 3
all for me.
4 CHAIRMAN CORRADINI: Okay. Thanks, 5
Dennis. Are there other members that have --
6 MEMBER KIRCHNER: Do we have a running 7
document table, for lack of the right description, of 8
all of the exemptions that are being requested and 9
what they -- in other words, we have open items here 10 that relate to Chapter 15.
11 We've seen this before. Is there some 12 table that the staff is maintaining that kind of 13 summarizes the overall application and what the --
14 connects the dots, as these open items and exemptions 15 are dispositioned?
16 Because we are getting it piecemeal. For 17 example, it's quite a while back we had exemption at 18 GDC 27. I don't want to reopen the topic, I just --
19 but from a process standpoint --
20 CHAIRMAN CORRADINI: But, it's still 21 sitting out there. It's still sitting out there, is 22 your point.
23 MEMBER KIRCHNER:
Yeah.
And if, 24 subsequent to Chapter 15 analysis, it's determined, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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76 for example, in that particular case that the CBCS 1
system needs electrical power, then that changes both 2
your INC and your electrical SERs.
3 MR. TANEJA: That's great. Actually, as 4
far as the table view mentioned, of course the DCA, 5
design certification application, is comprised of 6
several parts. And one part, I think it's part four 7
I believe, that lists all of the exemption requests.
8 So, that table exists there.
9 The way that the staff is dispositioning 10 or making a decision on those exemptions, is based on 11 documenting the results of those exemption reviews 12 within each chapter that they apply to. For instance, 13 we have, of course, Chapter 17, 18. And all of these 14 GDC exemptions that we have, we will have a write-up 15 on.
16 In this case, of course, we don't have the 17 answers. So, we are pointing at -- pointing to 18 Chapter 15 SER to -- and then, of course, when we 19 finalize the SER, we bring everything together that we 20 have, a complete resolution for each item.
21 CHAIRMAN CORRADINI: But, I think what 22 Member Kirchner's getting at is kind of a subset, 23 maybe a superset of my worry which is, normally, we 24 don't worry about process. We worry about technical 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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77 things.
1
- But, the technical issues are so 2
interconnected, I think we have to do -- we do have to 3
understand somehow the process so we're not confused 4
that we thought it was closed and it's not or it's 5
connected and we weren't aware of it or -- so, I think 6
I'll take the action item on our side to work with 7
Mike Snodderly to get some clarity.
8 MEMBER KIRCHNER: Okay.
9 CHAIRMAN CORRADINI: Any other member?
10 MEMBER MARCH-LEUBA: Are we grossly ahead 11 of schedule? Can I take quotes? It is such a strong 12 word.
13 CHAIRMAN CORRADINI: Actually that is such 14 a strong word, but go ahead.
15 MEMBER MARCH-LEUBA: Can I put a couple of 16 sentences on the record? And it refers to the 17 previous topic of discussion, so it might open up.
18 But, what I wanted to put on the record --
19 CHAIRMAN CORRADINI: But, if I might? Are 20 we talking about Chapter 7 and 8?
21 MEMBER MARCH-LEUBA: Seven.
22 CHAIRMAN CORRADINI: Oh, okay. I'm sorry.
23 MEMBER MARCH-LEUBA: The staff, on ACRS, 24 should not be in the business of specifying solutions.
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78 What the staff on ACRS should specify is requirements.
1 And this is -- refers to that diode. What the staff 2
should ensure is that there is a one-directional 3
communication and with sufficient reliability and 4
confidence that that will happen.
5 And then, it's up to the applicant to 6
decide how they want to satisfy that requirement.
7 That's stupid, if they put a hardware-based data 8
diode, then all their review will sail through and 9
they don't have to do anything. If they want to use 10 a software system, they're going to have to spend out 11 the money and time and incur risk.
12 But, we should not be in the business of 13 specifying a particular solution that it has to be a 14 diode from manufacturer X, with serial number 1234.
15 I just wanted to put in the record that even though we 16 kind of go that direction, what we really should do is 17
-- the requirement is that it has to be unidirectional 18 with extremely high properties.
19 CHAIRMAN CORRADINI: Thank you. Other 20 member comments?
21 MEMBER BROWN: Mike, Mr. Chairman, at the 22 risk of maybe a little tongue in cheek, let me be a 23 little tongue in cheek as I say this. I think the 24 question you asked, is there a logical sequence 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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79 through what are the remaining big nuggets that we 1
need to address, is yes.
2 I think that there is a yes answer to that 3
question. But, here is my tongue in cheek. So, we 4
started with six modules, no, 12. They can all fail.
5 Well, don't worry, because we've got lots of water.
6 There won't be a common mode failure. We don't have 7
a container. We have something else.
8 And oh, by the way, we don't need volume 9
control system, because it's all passive as long as 10 those valves open. And that's how come we don't need 11 off-site power, because we've got boo-coos of 12 batteries and we're going to go to lead acid batteries 13 so the footprint's smaller.
14 So, we've got criteria 17 and 18. We've 15 got exemptions for off-site power. We're scratching 16 our head about common mode failure or what happens 17 when one module's up in the air and the crane fails.
18 What is the sequence to get us through this forest?
19 I think the sequence is through the electrical power.
20 If we resolve and agree, we really don't 21 need off-site, if we can agree on the exemptions for 22 electrical
- power, and become comfortable with 23 reactivity insertion, and become comfortable that we 24 really do not need a makeup chemical control system, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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80 and that the paths of cooling systems cool because of 1
the inventory of the water and a large pool is never 2
compromised, we cut a path through this.
3 So, I think it really does begin with 4
electrical power. And I think the first dominos are 5
going to be criteria 18 and 18. That's tongue and 6
cheek. But, I've been thinking about this since we 7
started this. I'm intrigued by the box of batteries 8
and then not needing off-site power.
9 And that has major siting implications, 10 which are appropriate for an SMR. But, maybe as we 11 work our way through this, this might set the path for 12 how we go to the next SMR. Thank you.
13 MEMBER RAY: Implicit in a lot of these 14 discussions is what I've sometimes referred to as 15 incremental decision-making. I won't call it 16 approval, but decision-making.
17 One way to handle it is, well, no 18 decisions count until the final, until all of the 19 steps are laid out clearly at the end. Even though 20 this looked okay a year ago, the fact is, now we have 21 the complete picture and what we thought was going to 22 work, won't. And that seems, inevitably, inherent in 23 what we're about here and it just needs to be 24 explicit. It needs to be clear to everybody that 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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81 something that was agreed upon in step three, may have 1
been based on assumptions that are not valid once we 2
see step four.
3 That's the same sort of thing we've been 4
saying. And I don't find and I haven't been engaged 5
in the process that we're talking about here 6
previously. But, I just -- as I look at what's in 7
front of me now on that subject, it's just not 8
explicit.
9 It's not clear that there is a final 10 decision point, once all the information is available, 11 whether it has to do with off-site power or what it 12 has to do with, is we're not able to make a decision 13 on everything until everything is made explicit and 14 clear.
15 I think that's the same thing you're 16 talking about. You're talking about making decisions, 17 Mike, at least as I understood your point, first here 18 and then there, and which one's more important than 19 the next one.
20 And should we do this first and that?
21 Maybe the answer's yes, but I haven't been involved in 22 thinking through the process enough to know whether it 23 is or not. The one thing I can say is, it's not 24 explicit in anything I've seen that nothing counts 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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82 until the end.
1 MEMBER REMPE: But, I think this one's 2
very complicated. Maybe AP-1000 was just as 3
complicated. And some sort of table that documents 4
what chapters need to look at what items that we've 5
identified, just a tracking thing -- I agree with what 6
you're saying, Harold.
7 It's not a done deal until it's a done 8
deal. But, I think that some sort of documentation 9
would help us remember. It seems like there's a lot 10 of things that we're trying to remember.
11 MEMBER RAY: Well, I don't disagree, Joy.
12 I just am saying that -- and AP-1000 would be an 13 example. It, of course, didn't use this enhanced 14 process that we're engaged in now. And nothing was 15 final until it was final.
16 Although, there were times when we got 17 lectured about, I thought you agreed to this a year 18 ago and now you're disagreeing with me. Well, that 19 was because you have brought to the table information 20 that we didn't have then.
21 And that was the end of it, as far as that 22 process was concerned. This is perhaps different.
23 We'll have to talk about that separately.
24 CHAIRMAN CORRADINI: But, as I said, I 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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83 think it's my action item for the committee to try to 1
understand with Mike the path that the staff wants to 2
take and to see, from our standpoint, does this make 3
sense.
4 Because I think we, technically, need to 5
be able to have time to kind of mull over these 6
things. And I just don't want things to all arrive in 7
one, fell swoop at the end and us being told that 8
there's not enough time.
9 Because we'll make enough time because we 10 have to feel comfortable for the technical standpoint.
11 That's all I want to make sure. So, we'll go the 12 staff and find out what they're thinking is. Dennis?
13 MEMBER BLEY: Yeah. I'd like to get in 14 one more thing, since we don't go around the table at 15 the end. I really agree with this last discussion.
16 I think it's important. But, Jose brought up 17 something that I do want to comment on related to 18 Chapter 7, this one-way communication bit.
19 And he is, of course, right. And I should 20 be the one of everybody saying this. And whatever is 21 proposed, it's an issue of is it reliable enough. My 22 own, personal reason why I've been pushing with 23 Charlie for very specific hardware choices for the 24 one-way communication is I spend a fair amount of my 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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84 spare time reading reports from a number of 1
organizations in the states and around the world of 2
odd things that have happened inside computer systems.
3 And I've reached the point that I don't 4
think you can reach that point of being sufficiently 5
reliable without having that anchored in hardware.
6 But, the underlying principle is exactly as Jose said.
7 I agree with that.
8 CHAIRMAN CORRADINI: Okay. Thank you, 9
Dennis. All right. I don't see any more members 10 jumping on. So, I think we want to go to public 11 comments. So, if anybody's in the room, we're going 12 to open up the outside phone line.
13 MR. SNODDERLY: So, Mike, this is Mike 14 Snodderly. I think Shana Helton of the staff wanted 15 to make a statement real quick.
16 CHAIRMAN CORRADINI: Oh, okay. But, let's 17 get the outside phone line open. Shana, did you want 18 to go ahead? Please feel free.
19 MS. HELTON: Oh, okay. Thanks. Yeah. I 20 think earlier in the presentation on Chapter 7, we 21 alluded to an expectations memo from the office 22 director. And I just wanted to clarify that I think 23 we raised that too, as an explanation for our 24 philosophy applied during the review. That's -- the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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85 memo itself is not something we're ready to share on 1
the ACRS record in detailed form. But, just for the 2
high level philosophy and awareness.
3 CHAIRMAN CORRADINI: That's fine. It's 4
quoted. It's on the record. But, I understand your 5
point. It was more to give us background.
6 MS. HELTON: Yes.
7 CHAIRMAN CORRADINI: Okay.
8 MR. SNODDERLY: So, the memo exists.
9 CHAIRMAN CORRADINI: That's fine.
10 MR. SNODDERLY: There's just not extent 11 strong enough to put it on the record.
12 CHAIRMAN CORRADINI: Understood. Okay.
13 Is there -- we have nobody from the audience here in 14 the room to make a comment. Is there anybody on the 15 phone line that wants to make a comment? Please, make 16 a noise. The line's open. I know. So, I hear 17 nothing.
18 So, we'll close the line and thank 19 everybody. And we're going to thank the staff and 20 NuScale for listening in. And we're done with our 21 session. We have PNP in 20 minutes. And we also have 22 some of the members going to a side meeting on PRA in 23 20 minutes. So, we will wait until after lunch to 24 read through the draft letter, which, thanks to Member 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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86 Brown, is comprehensive. We're going to convene back 1
here at 12:45.
2 (Whereupon, the meeting in the above-3 entitled matter was concluded at 11:20 a.m.)
4 5
6 7
8 9
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Presentation to the ACRS Full Committee Staff Review of NuScale Topical Report TR-0915-17564, REVISION 1 SUBCHANNEL ANALYSIS METHODOLOGY Presenters:
Bruce Bavol - Project Manager, Office of New Reactors Syed Haider, Ph.D.- Reactor Systems Engineer, Office of New Reactors Matt Thomas - Reactor Systems Engineer, Office of New Reactors September 6, 2018 (Open Session)
Non-Proprietary 1
NRC Technical Review Areas/Contributors 2
Non-Proprietary Containment and Ventilation Branch NRO/DSRA/SCVB:
Reactor Systems NRO/DSRA/SRSB:
Jeffrey Schmidt Timothy Drzewiecki Matt Thomas
Staff Review Timeline TR-0915-17564, Subchannel Analysis Methodology NuScale submitted its Topical Report (TR)-0915-17564-P, Subchannel Analysis Methodology, Revision 1, on February 15, 2017 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML17046A333).
Staff issued the following request for additional information /
NuScale provided response:
- RAI 9080 - 09/11/2017 (ML17254A439) / 11/09/2017 (ML17313B205) & S1 (ML18061A109)
- RAI 9086 - 09/09/2017 (ML17252A688) / 10/30/2017 (ML17299A973)
- RAI 9099 - 09/02/2017 (ML17251A368) / 09/13/2017 (ML17251A368)
- RAI 9129 - 11/17/2017 (ML17321A597) / 01/15/2018 (ML18015A012)
Staff plans to issue its final SER in late October 2018.
Staff plans to publish the -A (approved) version of the TR in early 2019.
3 Non-Proprietary
Scope of the Staff Review (1/2)
Regulatory Basis
- General Design Criterion (GDC) 10, Reactor Design, in 10 CFR Part 50, Appendix A
- NuScale DSRS, Section 4.4, Thermal and Hydraulic Design
- 10 CFR 50.34, Contents of Applications; Technical Information NRC approved VIPRE-01 subchannel analysis code, version MOD-02 Elements of approval for the NuScale Subchannel Analysis Methodology (NSAM)
- VIPRE-01 applies to the NuScale steady-state and transient subchannel analyses
- Methodology fulfills the NRCs requirements in the SERs for VIPRE-01, MOD-01 and MOD-02.
- Methodology is independent of any specific CHF correlation, and is used for NuScale applications with an NRC approved CHF correlation.
- Methodology for treatment of uncertainties in the NuScale subchannel methodology is appropriate.
4 Non-Proprietary
Scope of the Staff Review (2/2)
Technical basis for the NRC staff review
- Nine conditions in the generic SERs for VIPRE-01 MOD-01 and MOD-02
- VIPRE-01 modelling assumptions and qualifications Areas requiring additional review
- NSAM applicability range and VIPRE-01 code limitations
- NuScale operating conditions
- Stability of the numerical scheme
- Inlet flow BC consistency; Core flow sensitivity
- Model geometry, nodalization, power distribution
- Qualification of VIPRE-01 MOD-02 models Information considered by NRC staff
- NuScale Topical Report, TR-0915-17564, Revision 1, Subchannel Analysis Methodology
- Responses to RAIs 9080, 9086, 9099, 9129 & Audit documents 5
Non-Proprietary
Staff SER Conclusions The NRC staff has reasonable assurance that the use of the VIPRE-01, MOD-02 code with the NSAM described in the TR is appropriate for the NuScale fuel thermal-hydraulic design and plant safety analyses, provided that the present SER condition is met.
Elements of NSAM Approval
- VIPRE-01 applies to the NuScale steady-state and transient subchannel analysis.
- NSAM fulfills the NRCs requirements in the SERs for VIPRE-01, MOD-01 and MOD-02.
- NSAM is independent of any specific CHF correlation and is used for NuScale applications if the methodology requirements are satisfied and if the NRC approves the CHF correlation as confirmed by Condition 1 of this SER.
- NSAM describes a methodology for treatment of uncertainties in the NuScale subchannel analysis that is appropriate.
6 Non-Proprietary
Additional ACRS Comments (1/3)
Comment 1 - Consider rewording:
Condition 1, An applicant referencing this TR in the safety analysis must also reference an approved CHF correlation. The basis for this Condition is provided in Section 4.1 of this SER.
Response - Condition 1 has been reworded to the following:
7 Non-Proprietary An applicant referencing this TR in the safety analysis must also reference an approved CHF correlation which has been demonstrated to be applicable for use with TR-0915-17564. The basis for this Condition is provided in Section 4.1 of this SER.
Additional ACRS Comments (2/3)
Comment 2 - Consider rewording the title, Two-Phase Flow Instability Found in SER (page 26)
Response - Reworded title to, Flow Perturbation Sensitivity Study and made corresponding changes to the body of the text:
a.
Removed/revised instability language b.
Struck sentence that stated, Consequently, the staff confirmed that the NPM was not operating near a two-phase instability point.
Note - An advance copy of the redline strikeout paragraph was provided to ACRS membership.
8 Non-Proprietary
Additional ACRS Comments (3/3)
Comment 3 - Thom vs. Chen graph - check that it is properly represented in the SER (page 10) Figure 1 Effect of the boiling heat transfer correlation on the fuel centerline temperature for the control rod misoperation case Response - Corrected legend in Figure 1 (Chen/Thom)
Note - An advance copy of the corrected Figure 1 was provided to ACRS membership.
9 Non-Proprietary
Questions/comments from members of the public before the closed session starts?
10 Non-Proprietary
Safety Evaluation with Open Items:
Chapter 7, Instrumentation and Controls NuScale Design Certification Application Review ACRS Full Committee Meeting September 6, 2018
NRC Staff Review Team
- Technical Staff
- Sergiu Basturescu, NRO
- Dawnmathews Kalathiveettil, NRO
- Dinesh Taneja, NRO
- Yaguang Yang, RES
- Project Manager
- Gregory Cranston, Lead Project Manager
- Omid Tabatabai, Chapter Project Manager 2
September 6, 2018 Chapter 7 - Instrumentation and Controls
Timeline 3
September 6, 2018 Chapter 7 - Instrumentation and Controls Date Activity 2014 - 2016 Pre-application Activities September 2016 Readiness Review March 2017 Accepted Revision 0 of the DCD for Review April 2017 ACRS Full Committee Meeting on HIPS Platform Topical Report March 2017 -
December 2017 Held 5 Public Meetings / Issued 9 RAIs / Completed 1 Audit January 2018 Draft SE with Open Items Completed March 2018 Applicant Submitted Revision 1 of the DCD April 2018 Confirmatory Items Incorporated into Revision 1 of the DCD August 2018 ACRS Subcommittee Meeting September 2018 ACRS Full Committee Meeting
Safety-Focused Review 4
September 6, 2018 Chapter 7 - Instrumentation and Controls ESFRA FUNDAMENTAL DESIGN PRINCIPLES Independence Redundancy Predictability &
Repeatability Diversity and Defense-in-Depth Simplicity
NuScale DCD Evaluation 5
September 6, 2018 Chapter 7 - Instrumentation and Controls TIER 1 2.5 (MPS/SDIS) 2.6 (NMS)
ATWS (50.62)
TMI Action Item 50.34(f)(2)(xx)
Exemptions TIER 2 IBR Documents Setpoints TeR (Tier 2 - 7.2.7)
Sensors TeR (Tier 2-7.2.6) 14.3.5 (ITAAC) 9.5.2 (COMS)
A S
A I
Chapter 7 TR-1015-18653 HIPS Platform
Three aspects to acceptance of exemption
- Built-in Diversity of the MPS
- ATWS Response Bounded by Plant Design and Chapter 15 analysis
September 6, 2018 Chapter 7 - Instrumentation and Controls 10 CFR 50.62(c)(1)
Exemption
SER with open items updated to address ACRS SC questions related to:
- Configuration of the data diodes
- D3 Coping Analysis
- Editorial Changes 7
Chapter 7 - Instrumentation and Controls ACRS Comments from NuScale Chapter 7 SC Meeting September 6, 2018
- The approach of DSRS Chapter 7 resulted in:
- A simple I&C architecture and the HIPS design, which are based on the fundamental design principles
- A completion of safety evaluation in an efficient and effective manner (safety-focused)
- The staff finds the I&C design to be safe and that it complies with applicable regulatory requirements 8
Chapter 7 - Instrumentation and Controls Conclusion September 6, 2018
Acronyms ACRS: Advisory Committee on Reactor Safeguards ASAI: application-specific action item ATWS: anticipated transient without scram CCF: common-cause failure CDF: core damage frequency CM: communications module COMS: communication systems D3: diversity and defense-in-depth DBC: digital-based CCF DCD: design control document DCIP: Division of Construction Inspection and Operational Programs DLSE: Division of Licensing, Siting and Environmental Analysis DSRA: Division of Safety Systems and Risk Assessment DSRS: design-specific review standard DSS: division of safety systems EDSS: highly reliable direct current power system EIM: equipment interface module ELVS: electrical distribution system EP: emergency preparedness ESFAS: engineered safety features actuation system ESFRA: enhanced safety-focused review EQ: environmental qualification HIPS: highly integrated protection system HPN: health physics network I&C: instrumentation and control IBR: incorporated by reference ICIS: in-core instrumentation system ITAAC: Inspections, Tests, Analyses, and Acceptance Criteria 9
Chapter 7 - Instrumentation and Controls September 6, 2018
Acronyms 10 Chapter 7 - Instrumentation and Controls September 6, 2018 MCS: module control system MPS: module protection system NRC: U.S. Nuclear Regulatory Commission NMS: neutron monitoring system NRO: Office of New Reactors NRR: Office of Nuclear Regulation NSIR: Office of Nuclear Security and Incident Response NuScale: NuScale Power, LLC PAMS: postaccident monitoring system PCS: plant control system PPS: plant protection system QA: quality assurance RAI: request for additional information RES: Office of Nuclear Regulatory Research RTS: reactor trip system RM: fixed area radiation monitoring SBM: scheduling and bypass module SC: subcommittee SFM: safety function module SDIS: safety display and indication system SER: safety evaluation report SVM: scheduling and voting module TeR: technical report TMI: Three Mile Island
12 Chapter 7 - Instrumentation and Controls Backup Slide September 6, 2018
NRC Staff Interfaces Chap.
7 PAMS NRO/DICP NRO/DLSE NRO/DSRA EQ & TMI-Action Item Exemption NRR/DE Coping Analysis &
ATWS Exemption NRO/DSRA Setpoints &
Tech Specs NRR/DSS Software QA
& ITP NRO/DCIP COMS NSIR/EP ATWS Exemption NRO/DSRA 12 September 6, 2018 Chapter 7 - Instrumentation and Controls
NuScale I&C Architecture 13 September 6, 2018 Chapter 7 - Instrumentation and Controls
Safety Classification 14 September 6, 2018 Chapter 7 - Instrumentation and Controls
Independence 15 Chapter 7 - Instrumentation and Controls Physical Electrical Communications Functional September 6, 2018
Redundancy
- MPS Redundancy
- Four separation groups and two divisions of RTS/ESFAS
- Internal Platform Redundancy
- NMS Redundancy
- Four separation groups
- Post-Accident Monitoring
- Two divisions of SDIS 16 Chapter 7 - Instrumentation and Controls September 6, 2018
MPS Platform (1 sec response time) 18 Chapter 7 - Instrumentation and Controls Predictability and Repeatability September 6, 2018 Input Sub-Module SFM SBM EIM Field Components SVM EIM Field Sensors
Diversity and Defense-in-Depth 19 Chapter 7 - Instrumentation and Controls September 6, 2018
20 Chapter 7 - Instrumentation and Controls Diversity and Defense-in-Depth (Cont.)
September 6, 2018
- The I&C architecture and systems incorporate the fundamental design principles with an overall focus on simplicity
- Simple RTS/ESFAS functions
- No closed/open loop control
- All safety-related functions are de-energize to actuate Simplicity 21 Chapter 7 - Instrumentation and Controls September 6, 2018
Non-Safety-Related Systems Segmentations 22 Chapter 7 - Instrumentation and Controls
- Segmentation of the MCS and PCS ensures that a failure of these systems does not adversely affect the safety functions
- This segmentation prevents any multiple failures resulting in spurious actuations or situations which put the plant in an unanalyzed condition
- Staff audited the technical basis of the segmentation analyses for both the MCS and the PCS September 6, 2018
24-hour timers 24-hour timers are part of the MPS boundary Powered by the non-safety-related EDSS MPS Undervoltage Design Feature Upon voltage degradation conditions, the MPS fails into a safe state 23 Chapter 7 - Instrumentation and Controls ACRS Comments from NuScale Chapter 8 SC Meeting September 6, 2018 Source: DCD Tier 2, Figure 7.1-1ai: Loss of AC Power to ELVS 24 Hour Timers Division I
24 September 6, 2018 Chapter 7 - Instrumentation and Controls 10 CFR 50.34(f)(2)(xx)
Exemption
- 10 CFR 50.34(f)(2)(xx) specifies power provisions for pressurizer relief valves, block valves, and level indicators
- Staff finds pressurizer level instrumentation is not necessary to maintain natural circulation cooling
Presentation to the ACRS Full Committee NuScale Power, LLC NuScale Design Certification Application Review Safety Evaluation with Open Items: Chapter 8 ELECTRIC POWER September 6, 2018
September 06, 2018 Chapter 8, Electric Power 2
- Technical Staff Reviewers
- Project Managers
Lead Project Manager - Gregory Cranston
Chapter 8 Project Manager - Omid Tabatabai Sheila Ray. P.E.
Raul Hernandez James Strnisha Nadim Khan Luis Betancourt Timothy Drzewiecki Robert Fitzpatrick Clinton Ashley Jeffrey Schmidt Fanta Sacko Thomas Scarbrough
September 06, 2018 Chapter 8, Electric Power 3
Overview of Chapter 8 Review NuScale submitted its DCA, Rev 0, in December 2016, and a Rev 1, on March 15, 2018. The staffs SER is based on the review of Rev 0 of the DCA.
Issued a total of 10 RAIs with 25 Questions. All RAIs have been responded.
The staffs SER with Open Items contains two open items and will be discussed in the subsequent slides.
Open and Confirmatory Items will be closed in Phase 4 of the Review.
September 06, 2018 Chapter 8, Electric Power 4
Technical Topics Chapter 8 - Electric Power Technical Topics NuScale Design:
The electric power system for NuScale design is comprised of non-safety related AC (or ac)(alternating current) and non-safety related DC (or dc) (direct current) power systems.
This design does not depend on onsite or offsite AC or DC electrical power system, including that from the transmission grid for safe operation.
The NuScale Power Plant design with non-reliance on electrical power accommodates a site location where an offsite transmission grid is not available.
The Offsite Power System includes the switchyard and one or more connections to a transmission grid, micro-grid, or dedicated service load.
The following nonsafety-related systems are the major constituents of the onsite AC power system Electrical High Voltage System (EHVS) (13.8 kV)
Electrical Medium Voltage System (EMVS) (4.16 kV)
Electrical Low Voltage System (ELVS) (480 Volts and 120 Volts)
Backup diesel generators (BDGs) (480 volts)
Auxiliary ac power source (AAPS) (13.8 kV)
The onsite DC power systems include the non-Class 1E EDSS and the non-Class 1E EDNS.
A safe and stable shutdown is automatically achieved and maintained for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> without operator actions.
September 06, 2018 Chapter 8, Electric Power 5
Technical Topics Chapter 8 - Electric Power Technical Topics Staffs review:
The staff reviewed the design of the electric power systems necessary for safe design and operation of the plant, or whose failure might adversely affect their safety-related or risk-significant safety functions.
The staff reviewed the design of the electric power systems in accordance with the applicable DSRS or SRP and consistent with the graded review approach.
The staff reviewed the offsite and onsite power system to ensure that it will perform its design function during all operating and accident conditions.
The staff reviewed the information pertaining to SBO in the FSAR to determine whether the design is capable of withstanding and recovering from a complete loss of ac electric power for a minimum of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Open Items
Exemptions to GDC 17 and 18 regarding the staff verifying that the design does not require safety-related power Pertains to all sections in Chapter 8
Electrical Penetration Assemblies Pertains to Section 8.3.1
September 06, 2018 Chapter 8, Electric Power 6
Technical Topics Chapter 8 - Electric Power Open Item 8.3 Exemptions to GDC 17 and GDC 18 FSAR, Tier 2, Section 8.3 and DCA Part 7 state that the design does not rely on safety-related AC or DC power systems
This position is supported by the application of the evaluation methodology described in NuScale topical report (TR)-0815-16497, Safety Classification of Passive Nuclear Power Plant Electrical Systems.
The open item relates to the exemptions to GDC 17 and 18 regarding the staff verifying that the design does not require safety-related power.
Furthermore, the staffs evaluation of accident analyses are in Chapter 15 which has not been completed to demonstrate that 1) fuel design limits and design conditions of the reactor coolant pressure boundary are not exceeded as a result of anticipated operational occurrences and 2) the core is cooled and containment integrity and other vital functions are maintained in the event of postulated accidents.
Staff issued a safety evaluation approving TR-0815-16497 with five additional conditions.
The NuScale DCA did not directly address the conditions of applicability and the five additional conditions.
NRC staff issued RAI 9359, Question 1-1, to address the conditions of applicability and the additional conditions associated with TR-0815-16497.
Staff is evaluating the RAI response.
September 06, 2018 Chapter 8, Electric Power 7
Technical Topics Chapter 8 - Electric Power Open Item - Electrical Penetration Assemblies Staff enquired about non-Class 1E electrical penetration assemblies (EPAs) as well as protective devices.
The applicant responded to RAI 9308.
The applicant indicated that non-Class 1E penetrations have no electrical circuits that use the associated containment penetration to perform a safety-related function. However, EPAs designated as non-Class 1E are subject to the same equipment qualification and seismic requirements as Class 1E EPAs.
The applicant provided clarity on self-limiting protective devices, such that the maximum fault current in these circuits would not damage the penetration if that current was available indefinitely.
The staff finds the response acceptable and currently, in the draft P4 SER, this is a confirmatory item.
September 06, 2018 Chapter 8, Electric Power 8
Summary Two Open Items:
Electrical Penetration Assemblies Relating to the exemptions to GDC 17 and 18, regarding the staff verifying that the design does not require safety-related power.
Staffs review:
Currently working on Phase 4 review.