ML18060A312

Transcript of Advisory Committee on Reactor Safeguards AP1000 Subcommittee Meeting - February 7, 2018 (Open Session), Pages 1-94

ML18060A312
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Issue date:	02/07/2018
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Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION

Title:

Advisory Committee on Reactor Safeguards AP1000 Subcommittee [Open Session]

Docket Number:

N/A Location:

Rockville, Maryland Date:

Feb 7, 2018 Work Order No.:

NRC-3521 Pages 1-94 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

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 UNITED STATES OF AMERICA 1

NUCLEAR REGULATORY COMMISSION 2

+ + + + +

3 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 4

(ACRS) 5

+ + + + +

6 AP1000 REACTOR SUBCOMMITTEE 7

+ + + + +

8 OPEN SESSION 9

+ + + + +

10 WEDNESDAY 11 FEBRUARY 7, 2018 12

+ + + + +

13 ROCKVILLE, MARYLAND 14

+ + + + +

15 The Subcommittee met at the Nuclear 16 Regulatory Commission, Two White Flint North, Room 17 T2B1, 11545 Rockville Pike, at 1:02 p.m., Harold B.

18 Ray, Chairman, presiding.

19 20 COMMITTEE MEMBERS:

21 HAROLD B. RAY, Chairman 22 RONALD G. BALLINGER, Member 23 DENNIS BLEY, Member 24 CHARLES H. BROWN, JR., Member 25

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 MICHAEL CORRADINI, Member 1

VESNA B. DIMITRIJEVIC, Member 2

WALTER L. KIRCHNER, Member 3

JOSE A. MARCH-LEUBA, Member 4

DANA A. POWERS, Member 5

JOY L. REMPE, Member 6

PETER C. RICCARDELLA, Member 7

GORDON R. SKILLMAN, Member 8

JOHN W. STETKAR, Member 9

MATTHEW W. SUNSERI, Member 10 11 ACRS CONSULTANT:

12 UPENDRA ROHATGI 13 14 DESIGNATED FEDERAL OFFICIAL:

15 WEIDONG WANG 16 17 ALSO PRESENT:

18 CLINT ASHLEY, NRO 19 JAMES BRADLEY CHAMBERLAIN, Southern Nuclear*

20 JASON EISENHAUER, Westinghouse*

21 DONALD HABIB, NRO 22 JESSE KLINGENSMITH, Westinghouse*

23 YUEN-LI LI, NRO 24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 KEVIN MCNAMEE, Westinghouse 1

GREG MAKAR, NRO 2

ANDREW PFISTER, Westinghouse 3

SHAYAN SINHA, Westinghouse 4

COREY THOMAS, Southern Nuclear 5

BOYCE TRAVIS, NRO 6

ANDREA D. VEIL, Executive Director, ACRS 7

KAI ZHANG, Westinghouse*

8 9

• Present via telephone 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 1

5 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 C-O-N-T-E-N-T-S 1

2 Opening Remarks 3

Harold Ray, ACRS 5

4 5

Westinghouse Topical Report 6

Shayan Sinha, Westinghouse 9

7 8

AP1000 In-Containment Cables Non-metallic 9

Insulation Debris Integrated Assessment 10 and draft Safety Evaluation 11 Clint Ashley, NRO 24 12 Boyce Travis, NRO 30 13 14 Public Comments 15 57 16 17 Adjourn 57 18 19 20 21 22 23 24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 1

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 P R O C E E D I N G S 1

1:02 p.m.

2 MEMBER RAY: Well, now that we've got 3

essentially everyone here, we'll please call the 4

meeting to order.

5 This is a meeting of the AP1000 Reactor 6

Subcommittee, a Standing Subcommittee of the Advisory 7

Committee and Reactor Safeguards.

8 I'm Harold

Ray, Chairman of the 9

Subcommittee.

10 ACRS members in attendance are Ron 11 Ballinger, Matt Sunseri, Dick Skillman, Dana Powers 12 will join us shortly as will Mike Corradini, Dennis 13 Bley, John Stetkar, Jose March-Leuba, Walt Kirchner, 14 Charlie Brown, Joy Rempe and Vesna Dimitrijevic. And, 15 thank you, Pete Riccardella.

16 He wasn't there when I wrote my list down 17 and so I missed him.

18 Thank you.

19 Also, ACRS Consultant, Upendra Rohatgi is 20 present and will assist the Subcommittee in this review.

21 Weidong Wang is the Designated Federal 22 Official for the meeting.

23 In this meeting, the Subcommittee will 24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 review a Westinghouse Topical Report, WCAP 17938-P 1

Revision 2 entitled AP1000 In-Containment Cables and 2

Non-Metallic Insulation Debris Integrated Assessment 3

and the associated staff Safety Evaluation Report.

4 The WCAP proposed changes to Tier 2 5

provisions of the existing AP1000 DCD. These 6

provisions are critical to ensuring that the natural 7

circulation function of the passive design is not 8

compromised by debris which might result from a pipe 9

break or from chemical effects following flooding.

10 These are GSI 191 considerations as 11 uniquely applied to natural circulation, differential 12 pressures in the AP1000.

13 The existing DCD requires that zero debris 14 result from a pipe break or flooding. And, this was 15 to be achieved by use of insulation and chilling 16 materials and by location or protection of electrical 17 cable so that debris would not result from pipe rupture 18 or flooding.

19 Further development of the design has made 20 it necessary to use alternate materials for which 21 suitable equivalency, those words in quotes, must be 22 demonstrated and to establish more specific 23 requirements for the electrical cable.

24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 The standard of zero debris remains a 1

requirement -- remains the requirement, therefore, our 2

review is to establish whether the alternate materials 3

and requirements addressed by the WCAP that we are 4

reviewing maintain that comply with that 5

requirement.

6 We will hear presentations from the NRC 7

staff and the representatives from the design 8

certification holder.

9 We have received no written comments or 10 requests for time to make oral statements for members 11 of the public regarding today's meeting.

12 Part of the presentations I expect after 13 our break will be closed in order to discuss information 14 that is proprietary to Westinghouse and its contractors 15 pursuant to 5 U.S. Code 552(b)(c)(4).

16 Attendance at these portions of the meeting 17 that deal with such information will be limited to the 18 NRC staff and its consultants, Westinghouse and those 19 individuals and organizations who have entered into 20 appropriate confidentiality agreement with them.

21 Consequently, we will need to confirm at 22 that time that we have only eligible observers and 23 participants in the room for the closed portion.

24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 The Subcommittee will gather information, 1

analyze relevant issues and facts and formulate 2

proposed positions and actions as appropriate, and this 3

is important, for deliberation by the Full Committee.

4 The rules for participation in today's 5

meeting have been announced and are part of the Notice 6

of this meeting published previously in the Federal 7

Register.

8 A transcript is being kept and will be made 9

available as stated in the Federal Register Notice.

10 Therefore, we request that participants 11 in this meeting use the microphones located throughout 12 the room when addressing the Subcommittee.

13 The participants should first identify 14 themselves and speak with sufficient clarity and volume 15 so that they may be readily heard.

16 We'll now proceed with the meeting, but 17 first, let me turn to Don and ask if he has any opening 18 remarks.

19 MR. HABIB: Thank you very much and I 20 appreciate this opportunity to make the presentations 21 and we don't have any other remarks at this time.

22 MEMBER RAY: That's fine.

23 Then, I'll turn it over to which ever of 24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 the gentlemen here will take charge for Westinghouse 1

and please you to proceed.

2 MR. SINHA: Good afternoon.

3 My name is Shayan Sinha, I will be 4

presenting the public slide material for Westinghouse.

5 We also wanted to thank you for the 6

opportunity, we are grateful to be able to discuss this 7

topical report with the ACRS.

8 I'd like to begin by talking about a little 9

bit of background of the GSI 191 related design basis, 10 specifically, how they apply to AP1000.

11 So, the resolution of GSI 191 requires 12 nuclear plants to place limits on potential sources 13 of debris inside containment. This is to ensure that 14 you don't have potential -- some blockage following 15 a loss of coolant accident where there's a pipe break 16 inside containment.

17 The AP1000 actually significantly reduces 18 and eliminates many of the debris sources that are found 19 in typical Generation II plants. And, by incorporating 20 a lot of these lessons learned into the design prior 21 to construction and operation.

22 The maximum allowable fibrous debris 23 inside containment for AP1000 is 6.6 pounds. And, this 24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 is all attributable to latent debris. So, in other 1

words, the expectation is that following a loss of 2

cooling accident, there would be no debris generated 3

as a result of that -- fibrous debris generated as a 4

result of that LOCA.

5 There's metal reflective insulation used 6

within the AP1000 extensively including only insulation 7

for the reactor vessel itself.

8 The DCD provides requirements of what must 9

be demonstrated if and AP1000 decides to use a type 10 of insulation other than metallic reflective 11 insulation, or MRI. And, these requirements include 12 that we need to demonstrate that the insulation is a 13 suitable equivalent to MRI for the purposes of GSI 191.

14 And, in order to qualify as a suitable 15 equivalent, testing must be performed to show that 16 debris is not generated or transported.

17 And, finally, there's a requirement in the 18 DCD that states that the suitable equivalent testing 19 must be approved by the NRC.

20 So, the purpose of this topical report, 21 WCAP 17938, is to gain approval for three items.

22 The first item is to establish a zone of 23 influence applicable to AP1000 in-containment cables 24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 that demonstrates that the cabling will not generate 1

debris following a LOCA.

2 The second is to gain approval for that 3

the non-metallic insulation used in the AP1000 reactor 4

vessel insulation system is a suitable equivalent to 5

MRI for the purposes of GSI 191.

6 And then, the third item is to gain approval 7

for the AP1000 to utilize the approved methodology for 8

defining debris generation break size from NEI Guidance 9

Document 04-07.

10 So, this methodology is generically 11 approved, is part of the safety evaluation for NEI 04-07 12 by the NRC. However, what we're trying to do in this 13 topical report is gain approval to use this methodology 14 for AP1000.

15 And, as I'll demonstrate in the -- I'll 16 discuss in the next few slides, testing analysis has 17 been completed that shows that the cabling and the NMI 18 does not generate debris following a LOCA.

19 So, there was two factors that led to the 20 creation of this topical report, WCAP 17938. The first 21 factor is that the AP1000 -- there was an issue 22 identified that the AP1000 cabling contained fibers 23 and other materials that were not originally considered 24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 as a debris source when -- as part of the AP1000 GSI 1

1919 related evaluations.

2 So, as this issue was resolved, corrective 3

actions were taken and these corrective actions 4

included developing a testing program to establish a 5

zone of influence for the containment cabling.

6 And, the second factor is that the 7

non-metallic insulation is required for certain 8

subcomponents of the reactor vessel insulation system 9

because some of these subcomponents performed functions 10 other than insulation such as shielding or in vessel 11 retention.

12 So, if you take a look at this diagram here 13 to the right, the CA31 module shown at the top of the 14 reactor vessel performs a shielding function. It is 15 needed to prevent radiation streaming upward into 16 containment.

17 And then, the lower neutron shield which 18 is more on the bottom half of the reactor vessel shown 19 here forms a shielding function that provides shielding 20 for the lower reactor cavity.

21 Then, finally, the water inlet doors at 22 the very bottom of the vessel support this in vessel 23 retention support for certain beyond design basis 24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 events.

1 MEMBER REMPE: So, when I was reviewing 2

the information for this meeting, I kept thinking to 3

myself, jeepers, shouldn't Westinghouse have known that 4

the cabling -- I mean, this isn't your first PWR, right, 5

that would exist and these materials might exist and 6

that you might need this material?

7 And, why, you know, right now, the way you 8

presented it, it was like, well, okay, we figured you 9

might have to do some qualification for NMI.

10 But, I just was surprised. I mean, did 11 this all come as a surprise to you all and you didn't 12 think about it during design certification?

13 MR. PFISTER: So, I'll take the question 14 on cabling first because they're separate.

15 Traditionally, cabling isn't considered 16 a source of debris for GSI 191. As we try to do, we 17 look into what the industry has done. That's not a 18 source that's generally being considered as a debris 19 generation source.

20 Or, if it is, it's just rolled into the 21 other margin for operating plants.

22 And, the insulation design within cabling 23 is going to be vendor specific.

24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 And so, as we went through the process of, 1

you know, defining the specification for cabling, 2

working with vendors and procuring cabling, you know, 3

we became aware that there is fibrous materials as 4

insulation within some cables, not all cables. But, 5

that is a material that cable vendors use.

6 So, within the design certification, 7

there's some generic language that says, you know, 8

insulation or other materials won't become debris.

9 And, because we work through NEI guidance 10 where we have established ZOIs, whether it was through 11 an NEI program or a PWR OG program or something specific 12 for AP1000, there had never been an established ZOI 13 for cabling.

14 So, we identified, this is a gap and said, 15 not necessarily that it is a debris source, but it 16 certainly could be one. So, we had to take the 17 necessary steps to say, where must it be located 18 relative to high energy lines in order to preclude it 19 from being a debris source?

20 So, that's where this came from.

21 MEMBER RAY: Where -- you said -- well, 22 we are going to have some specific questions about the 23 testing of cabling and so on. Is that best addressed 24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 in the proprietary portion of the discussion?

1 MR. PFISTER: Yes.

2 MEMBER RAY: Okay, go ahead, Walt.

3 MEMBER KIRCHNER:

This might be 4

proprietary, too, so I can hold it. I was just curious 5

what the shielding material is that --

6 MR. PFISTER: So, we use two different 7

shielding materials. So, I'll speak generically about 8

them.

9 MEMBER KIRCHNER: Okay, or you can just 10 wait until later and we can --

11 MR. PFISTER: Yes, and then I can answer 12 it generically now and then --

13 MEMBER KIRCHNER: And, not to force you 14 all the way back to slide two or one, how do you know 15 you have 6.6 pounds of latent material? And, how do 16 you measure that and what's the -- is there a tech spec 17 that governs operation as a result of that?

18 MR. PFISTER: So, as to the shielding 19 question first and --

20 MEMBER KIRCHNER: There's some precision 21 there --

22 MR. PFISTER: -- the 6.6 --

23 MEMBER KIRCHNER: -- that's often hard to 24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 measure in light weight --

1 MR. PFISTER: Yes.

2 MEMBER KIRCHNER: -- material.

3 MR. PFISTER: So, the shielding material, 4

so within the lower neutron shield, we use a boron 5

silicone material. And, to note, that all the 6

shielding is non-safety related shielding. So, this 7

is shielding that we only credit during normal 8

operations and shutdown, not shielding that we credit 9

for accidents.

10 And, within CA31, which is shield --

11 essentially shield blocks that will go into more detail 12 13 MEMBER RAY: Let interrupt you for just 14 a second.

15 You were asking about the 6.6, weren't you?

16 (OFF MICROPHONE COMMENTS) 17 MR. PFISTER: He asked -- so, I was 18 answering the question about shielding then I was going 19 to answer --

20 MEMBER RAY: Okay.

21 MR. PFISTER: -- the 6.6.

22 MEMBER RAY: I missed the --

23 MR PFISTER: And, within the CA31 which 24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 are 60 individual blocks inherently designed within 1

the refueling cavity floor, we use boron carbide for 2

shielding there.

3 So, relative to your second question, how 4

do we demonstrate 6.6 pounds? And so, ultimately, 5

that's something that must be demonstrated prior to 6

fuel load and prior to each refueling.

7 It's done in almost the exact same way you 8

would do it for an operating PWR is that, as part of 9

your containment cleanliness program, you have to 10 quantify and demonstrate containment cleanliness. You 11 typically do that, they almost call it a white glove 12 test where you go around and you test certain areas.

13 And then, you know, the -- I think the 14 industry standard is, of the debris that you quantify 15 for all of containment, the assumption is 15 percent 16 of that debris is fibrous.

17 And so, when they do their containment 18 cleanliness and they go in, you know, to their pre-fuel 19 load inspections, you know, as part of their containment 20 cleanliness program, that would define how you measure 21 the total amount of debris.

22 And then, industry standard is 15 percent 23 of that is assumed to be fibrous.

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 MEMBER KIRCHNER: What struck me was that 1

the 6.6 is a fairly precise number.

2 MR. PFISTER: Yes. And so, the 6.6 was 3

established during design certification as part of the 4

fuel assembly and sump testing. And so, that's 5

essentially the limit we were able to push our fuel 6

assembly testing to.

7 You know, with the combination of latent 8

debris and chemical debris to show we didn't get 9

unacceptable DP across the fuel.

10 MEMBER KIRCHNER: No, I knew the basis for 11 the amount, but I was curious about how you measure 12 it to that precision.

13 MEMBER RICCARDELLA: Are your limits 14 smaller than a conventional PWR because of the passive 15 nature of the system?

16 MR. PFISTER: Essentially, the answer is 17 yes. So, you'll see a range of limits within PWRs.

18 You'll see what they consider high fiber plants where 19 the limits are much, much higher.

20 And, you'll see low fiber plants. You 21 know, we're probably the lowest of the low fiber plants.

22 But, a lot of that's driven by acceptable 23 DP we can withstand due to the passive recirculation.

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 MEMBER RICCARDELLA: Okay, thank you.

1 MR. SINHA: Okay, so, on slide six, this 2

just summarizes the results that came from our program 3

to evaluate the non-metallic insulation and the 4

in-containment cables.

5 So, firstly, the first bullet talks about 6

the zone of influence of four diameters. There are 7

four times the debris generation break size was 8

established for in-containment cables. And, this was 9

done through an extensive large-scale jet impingement 10 testing program which was conducted at a facility that 11 had been previously used by the pressurized water 12 reactor zoners group for other operating plant 13 evaluations related to GSI 191.

14 And so, this cable as the OI, was able to 15 be incorporated into the design requirements and then 16 the location of the cables and the cable trays, we 17 consider them as, you know, as the locations were 18 developed for the plant.

19 The WCAP also invokes the alternative 20 evaluation methodology from NEI 04-07 for determining 21 the limiting RCS break size, you know, in our debris 22 generation evaluations.

23 And so, this was done through a structural 24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 evaluation that reviewed whether the hot leg or cold 1

legs would fully separate following a loss of coolant 2

accident.

3 And then, this is compared against the NEI 4

04-07 criteria and shown to be acceptable for AP1000.

5 And then, finally, jet impingement and 6

submergence testing program was performed for the 7

non-metallic insulation. And, the insights from this 8

programs were used to strengthen the design of the 9

elements for the reactor vessel insulation system.

10 So, essentially, this resulted in design 11 changes that used a thicker and more robust 12 encapsulation for the neutron shield blocks.

13 And then, the final slide is the 14 conclusions for the public portion.

15 The jet impingement testing program that 16 was conducted was used to justify a cable ZOI for L/D 17 for the AP1000 in-containment cabling.

18 The cabling was found to contribute no post 19 LOCA debris.

20 The application of the NEI 04-07 ultimate 21 break methodology was acceptable for the AP1000. And 22 then, the encapsulated non-metallic insulation was 23 found to not produce debris when subjected to the jet 24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 impingement from the limiting RCS lines -- line breaks.

1 And then, the cabling and the NMI were 2

evaluated for chemical debris and found that neither 3

types of components would contribute to chemical 4

debris.

5 And, this -- the conclusions related to 6

jet impingement and chemical debris were used to make 7

the conclusion that the non-metallic insulation in the 8

reactor vessel insulation for AP1000 is a suitable 9

equivalent to MRI for the purposes of GSI 191.

10 And then, I just wanted to highlight the 11 overall conclusion that the WCAP justifies that there's 12 no debris -- no new debris generated for AP1000 from 13 the cables and the non-metallic insulation.

14 So, that is all we have for the public 15 portion. We can open it up for questions.

16 MEMBER BROWN: Just a question on the 17 previous slide, two previous slides, six.

18 What the design was changed to use thicker 19 and more robust -- what's meant by more robust? I 20 missed that if you --

21 MR. SINHA: Yes, we're going to detail it 22 more --

23 MEMBER BROWN: You're going to talk about 24

24 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 that -- okay, then, we'll wait.

1 MR. SINHA: So, it's the weld type that 2

we use.

3 MEMBER BROWN: It's the what -- the weld 4

5 MR. SINHA: We use a more robust weld type.

6 MEMBER BROWN: -- the welding --

7 MR. PFISTER: The welding techniques that 8

we use.

9 MEMBER BROWN: Okay, all right.

10 MEMBER RAY: Any other questions?

11 MR. ROHATGI: Anyway, are you going to 12 change the weld technique that you'll discuss later 13 on?

14 MR. SINHA: Yes.

15 MR. ROHATGI: Because they're not going 16 to be all the same techniques?

17 MR. SINHA: Correct.

18 MR. ROHATGI: Okay.

19 MR.

SINHA:

Yes, the different 20 subcomponents have different weld techniques.

21 MEMBER RAY: Okay, we've got the scope of 22 the discussion here clear, I think, and the purpose 23 of it and so on.

24

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 Anything else?

1 (NO RESPONSE) 2 MEMBER RAY: If not, we will have an 3

opportunity for public comment following the staff open 4

discussion.

5 MR. SINHA: I apologize, I actually had 6

-- there's one other comment I wanted to make was about 7

the utility -- the licensee, Southern Nuclear wanted 8

to make a comment about the usage of this topical report 9

for Vogtle Units 3 and 4.

10 MEMBER RAY: Okay, that's fine. Please 11 12 MR. THOMAS: Yes, this is Corey Thomas from 13 Southern Nuclear, Vogtle 3 and 4 Licensing.

14 First of all, this WCAP is important to 15 us from a construction sequence to allow us to continue 16 with the installation of non-metallic insulation inside 17 containment and installation of the cable inside 18 containment.

19 Thank you.

20 MEMBER RAY: Yes, and because of that, we 21 were all geared up to write your letter this week.

22 But, we understand that we've got a little more time.

23 So, we'll have the Full Committee consider whether 24

26 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 they wish to write a letter on right now forecasted 1

to be the April Full Committee meeting.

2 Okay, again, we're in public session. We 3

will ask for any public comment, but following the staff 4

presentation.

5 So, we'll trade places now and proceed with 6

the staff and then return -- we may get to the closed 7

session before our break if things continue to move 8

this quickly.

9 And, you'll want to remove that card, 10 that's good.

11 Okay, Don, could you launch the ship, 12 please?

13 MR. HABIB: Thank you and good afternoon.

14 The staff's here to make our presentation -- public 15 presentation for the AP1000 In-Containment Cables 16 Non-metallic Insulation Debris Integrated Assessment 17 and the draft Safety Evaluation that it prepared.

18 So, these are our speakers and they'll 19 introduce themselves.

20 I'm going to turn it over to Clint Ashley 21 who's the first presenter.

22 MEMBER RAY: Before you do, let me say, 23 on the agenda I was given, maybe I should direct to 24

27 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 Weidong, shows only Westinghouse speaking in the closed 1

session. That implies to me that you don't have any 2

closed material to present.

3 MR. HABIB: That's correct. But we do --

4 MEMBER RAY: But, we may have questions 5

for you that need to be discussed in closed session.

6 So, I just want to make that clear to everyone that 7

staff will remain with us for purposes of questions 8

that involve proprietary material and that could be 9

relevant to the discussion we're about to have.

10 So, anyway, for all intents and purposes 11 you'll be with us also in the closed session.

12 Go ahead.

13 MR. ASHLEY: So, good afternoon.

14 My name is Clint Ashley. I'm a Technical 15 Reviewer in the Office of New Reactors.

16 And, we'd all like to thank you for the 17 opportunity to present our draft Safety Evaluation on 18 this particular topical report.

19 And, we do look forward to addressing any 20 of your questions. And, as you mentioned, I think these 21 slides are non-proprietary. But, we recognize that 22 some of the discussions may go into proprietary 23 information and we'll hold those over until the closed 24

28 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 session.

1 So, going back one slide, we're just going 2

to cover a few topics here initially and I'll discuss 3

the introduction and overview and then we'll roll right 4

into the staff's approach and our findings.

5 The next slide shows the presenters here, 6

members of the technical team as well as the project 7

manager. We also worked closely with NRR Technical 8

Reviewer, Steve Smith, as part of this process. So, 9

I wanted to make sure I acknowledged their involvement 10 in this review.

11 So, the next several slides really just 12 try to explain at a base level what a topical report 13 is for those that may not be familiar with them, what 14 guidance the staff used during the review.

15 And, you've already heard Shayan this 16 morning what this topical report is all about. So, 17 I'll probably be able to breeze through some of those 18 background slides.

19 The -- a topical report is a standalone 20 document containing technical information about a 21 nuclear power plant safety topic and provides the 22 technical basis for a licensing action.

23 And, typically, the objective is to add 24

29 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 value by improving the efficiency of other licensing 1

processes. For example, the process for reviewing 2

license amendment requests or we call them LARs.

3 They improve the efficiency of the 4

licensing process by allowing the staff to review 5

proposed methodologies, designs or other safety related 6

subjects on a generic basis so that they may be 7

implemented by reference by multiple licensees once 8

approved by the NRC staff.

9 And, in this particular topical report, 10 Westinghouse updates the AP1000 plant safety analysis 11 related to generic safety issue 191 which is concerned 12 with the assessment of debris on pressurized water 13 reactor sump performance.

14 The WCAP seeks review for three items and 15 we'll talk about these in the next few slides.

16 The main guidance for evaluating this 17 topical report is the Nuclear Energy Institute, NEI 18 document 04-07. And, that was published in 2004 time 19 frame, if I'm not mistaken.

20 The NEI 04-07 submission as approved in 21 accordance with the staff's Safety Evaluation provides 22 an acceptable overall guidance methodology for the 23 plant specific evaluation sump performance.

24

30 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 And, that staff safety evaluation was also 1

completed in 2004 time frame.

2 One thing the NEI 04-07 document mentions 3

is that it didn't really have enough information to 4

conclude anything about chemical effects other than 5

more study was needed.

6 So, the industry put together another 7

topical report, 16530, that the staff approved. And, 8

I believe that approval was completed in maybe the 2008 9

time frame.

10 So, as Westinghouse already communicated 11 earlier, the AP1000 safety evaluation really is based 12 on a zero loss of coolant accident generated fibrous 13 debris source term.

14 So, no LOCA generated fibrous debris, 15 they've gotten rid of all that fibrous insulation that 16 a lot of operating plants are plagued with.

17 And, the way they achieve this is through 18 the use of metal reflective insulation. This is on 19 main coolant piping, steam generators, all those large 20 main coolant system components.

21 The DCD also does allow or permit a suitable 22 equivalent insulation. And, as part of this WCAP, 23 Westinghouse recognizes that there's going to be at 24

31 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 least three locations for suitable equivalent 1

insulation to replace metal reflective insulation.

2 And, the last bullet on this slide, the 3

DCD does specify that NRC approval is required to use 4

a suitable equivalent insulation.

5 Westinghouse already communicated this 6

information. It's about electrical cabling. And, it 7

was -- I would view it as more of a discovery item as 8

Andy Pfister had communicated. So, I don't think 9

there's any need to brief anymore on this slide.

10 Next?

11 So, in light of the AP1000 design basis 12 in which the AP1000 design does not generate fibrous 13 debris during a LOCA, and that coupled with a detailed 14 design reviews which took place on cabling and 15 non-metallic insulation.

16 The WCAP seeks approval for the following 17 three items.

18 And, the first one is zone of influence 19 for electrical cabling.

20 The second is use of non-metallic 21 insulation as a suitable equivalent to metal reflective 22 insulation.

23 And, the last one is use of the NEI 04-07 24

32 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 alternate evaluation methodology for assessment of 1

debris generation.

2 And, the next slide talks about what it 3

means to be a suitable equivalent insulation from a 4

debris generation perspective.

5 Testing must be performed that subjects 6

the insulation to conditions that bound the AP1000 plant 7

conditions.

8 Testing demonstrates that debris would not 9

be generated to include chemical debris.

10 And, this must be approved by the NRC.

11 That's all called out in the DCD.

12 And so, the three requests for NRC approval 13 are detailed in the subsequent slides.

14 And, at this point, I'll turn it over to 15 Boyce Travis who's going to talk through the items one 16 and two.

17 MEMBER RAY: Boyce, before you begin, let 18 me just say that these points that were just covered 19 about in quite detail in the DCD were in anticipation 20 that we would be here having this discussion at the 21 time.

22 That sort of detail isn't spelled out 23 later, but it was just in unresolved matters as to 24

33 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 whether MRI would be totally satisfactory throughout 1

the design. So, there was a provision made for suitable 2

equivalent. Here we are.

3 Go ahead.

4 MR. TRAVIS: As Clint mentioned, my name's 5

Boyce Travis. I'm a Technical Reviewer in the 6

Containment Branch at NRO. I'll be discussing the 7

first two requests in the WCAP.

8 So, item one of the WCAP requests approval 9

for a ZOI for electrical cabling and containment. In 10 order to determine the acceptability of this, staff's 11 goal was to ensure that the tested cables represented 12 a bounding set for all the AP1000 cables and to ensure 13 the test conditions for the facility bound the target 14 conditions expected in the AP1000 plant.

15 In order to make this determination, staff 16 observed the cable jet impingement testing facility.

17 We assessed the applicability of the test facility 18 to produce the conditions representative of the AP1000 19 plant.

20 And, in doing so, we reviewed both the test 21 material -- physical test materials and the prepared 22 test reports for the facility. And, as part of our 23 review, we issued RAIs.

24

34 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 And some additional detail on how we came 1

to our finding is on the following slide.

2 So, as part of the review, staff looked 3

at observations from previous NRC visits to the test 4

facility.

5 In about six, seven years ago, the Office 6

of Research visited the facility which was, at the time, 7

being contracted by the PWR Owners' Group. At that 8

time, the test facility was instrumented to determine 9

whether it was capable of producing jet conditions that 10 would be representative of the large PWR.

11 At the time, the group from research found 12 that they thought it would be able to do so. And, this 13 topical report leverages some of that instrumented 14 testing in its evaluation of the test facility that 15 they used for both the cabling and the NMI.

16 So, as part of the review and the topical 17 report, the test conditions that were generated by the 18 facility for this testing were compared to the facility 19 conditions from the previous testing to verify both 20 repeatability and the expected target conditions were 21 at jet impingement pressures expected for a PWR, in 22 this specific case, the AP1000.

23 MEMBER RAY: Yes, I think we have some 24

35 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 questions perhaps on this point. Our consultant will 1

discuss them.

2 I don't think they will go into proprietary 3

material. They have to do with process.

4 MR. TRAVIS: Okay.

5 MEMBER RAY: And, your oversight of how 6

you're auditing of it.

7 But, if they do, then, of course, we'll 8

stop and resume after we go into -- but we should discuss 9

in the open session as much as we can that's not 10 proprietary.

11 So, go ahead.

12 MR. ROHATGI: Yes, looking at this, when 13 you did the cable testing and you're saying the 14 conditions will bound the LOCA conditions in AP1000?

15 MR. TRAVIS: That's correct.

16 MR. ROHATGI: But, that didn't come out 17 very clearly because, I don't want to go in detail of 18 the size of the jet and all, but --

19 MEMBER RAY: Try and use the other 20 microphone also. There's two microphones not being 21 used there.

22 MR. ROHATGI: Okay, so, what I wanted to 23 know is that how do you decide that this test facility 24

36 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 bounds the condition expected in the containment?

1 MR. TRAVIS: Sure.

2 So, I'll try to do this at a high level 3

and that's all I can do in the open session.

4 But, with respect to the pressure produced 5

by the -- so, the previous testing performed at the 6

facility was well instrumented. And so, for an 7

expected conditions in the -- for expected test 8

reservoir conditions, we have an expected pressure 9

profile that's going to be generated by the jet.

10 At all conditions -- I'll say this, based 11 on the locations that the cables were placed during 12 testing and the distance the cables were from the jet 13

-- from the facility exit nozzle, the instrumented 14 conditions led staff to believe that for those -- for 15 the -- specifically with regard to the cables, once 16 we get into talking about the blocks, it becomes a little 17 more nebulous.

18 But, specifically with regard to the 19 cables, the pressure the cables experienced from the 20 jet is -- would be equal to a greater than that they 21 would see in the AP1000 based on the instrumented test 22 facility and the reservoir conditions of the test 23 facility as was reviewed by the staff.

24

37 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 MR. ROHATGI: So, the jet has a velocity, 1

I don't know, stop me if I go in anything -- so the 2

jet which is running impinged has a velocity profile 3

and the center of the jet will have the largest static 4

pressure?

5 MR. TRAVIS: That's correct.

6 MR. ROHATGI: I mean static pressure may 7

be uniform. So, the question, so, when you impinge 8

on this cable, have you moved around the jet to see 9

each of the cables is subjected to largest static 10 pressure or it was just one short?

11 And, because the damage was -- seems to 12 be random from some cable on the left were damaged or 13 sometimes on the right, but how do they connect to the 14 center of the jet?

15 MR. TRAVIS: So, I think we're going to 16 be getting in to proprietary discussion very quickly 17 there.

18 MR. ROHATGI: Yes, I'll wait, I'll wait.

19 MR. TRAVIS: So, if we could hold that to 20 where I can fully anser the question?

21 MR. ROHATGI: That's fine, thank you.

22 Okay, thank you.

23 MR. TRAVIS: Okay, so, I guess I'll go back 24

38 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 and try and continue -- pick up where we left off.

1 So, as I was saying, as part of the review, 2

staff determined that the facility produced conditions 3

that would bound the expected conditions at a distance, 4

a scaled distance from the jet as would be experienced 5

in the AP1000.

6 And so, as part of testing, the applicant 7

performed tests at different scale, length over 8

diameter ratios and determined a ZOI for what -- when 9

damage would occur, when the onset of damage would occur 10 and when no damage would occur due to cables.

11 And then, did repeated tests to determine 12

-- to make sure that those conditions were represented 13 or that those test conditions could be repeated.

14 And so, that was, at one point, the 15 applicant conservatively made their request that their 16 acceptable ZOI would be that which showed no debris 17 generation.

18 The primary concern is quantifying a ZOI 19 for the cables based on experimental observation and 20 debris generation. And so, by choosing a ZOI that 21 showed no damage to the cables, the staff felt that 22 was a conservative choice in making what would be an 23 acceptable ZOI for cable damage.

24

39 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 I'll note that the applicant tested both 1

aged and unaged cables to serve as a representative 2

bounding set. And, those cables were aged both 3

thermally and radiation -- they were fresh and unaged 4

cables -- fresh and unaged cables tested both from a 5

thermal perspective and a radiation perspective.

6 We can move on to the next slide.

7 MEMBER RAY: Could you repeat that for the 8

record just to make sure it's --

9 MR. TRAVIS: Sure.

10 MEMBER RAY: -- clear. It was a little 11 12 MR. TRAVIS: So, the --

13 MEMBER RAY: -- trailing off at the end 14 there.

15 MR. TRAVIS: Yes.

16 There were aged and unaged cables tested.

17 Aging consisted of both of thermal and radiation aging.

18 MEMBER POWERS: The thermal aging and the 19 radiation aging were done together or separate?

20 MR. TRAVIS: That I would to -- I believe 21 separately, but I would have to go back and check that 22 to be sure.

23 MEMBER POWERS: Well, NRC funded Roger 24

40 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 Cliff to look at in-containment cable degradation 1

during service life. And, what he observed was that 2

cable damage due to radiation and thermal conditions 3

were synergistic. So, why would you do the aging 4

separately if there's synergism between thermal and 5

radiation damage?

6 I mean, this is research funded by the NRC, 7

it's publically available.

8 MR. TRAVIS: So, I think that's a fair 9

question. As I said, I'd have to go back and look at 10 when the aging was performed.

11 I will say that, yes, because at the test 12 facility and saw the cables. They were tested and I 13 have verified the aging reports that do exist.

14 But, if we can hold my full answer to closed 15 session, I'll go back and -- I have the topical report 16 right there, and go back and look and make sure that 17 I have a complete answer for you --

18 MEMBER POWERS: I'm very patient.

19 MR. TRAVIS: -- in a few minutes.

20 MEMBER POWERS: -- I'm not going anywhere 21 until Saturday.

22 MR. TRAVIS: Understood.

23 And so, back to the slides.

24

41 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 With regards to the cabling, the staff 1

found that the topical report provided an acceptable 2

technical basis for determining no debris will be 3

generated by the cables at or beyond the proposed ZOI.

4 The testing generated -- the testing as 5

part of the WCAP demonstrated no debris generation would 6

occur outside that ZOI. And, therefore, the staff 7

determined that that ZOI was acceptable.

8 As part of this finding, the staff imposed 9

the limitation and condition as part of the WCAP stating 10 that performance of cables within the ZOI, if any are 11 present, is outside the scope of the WCAP and any cabling 12 that was located within the ZOI would have to be assessed 13 by an applicant or a licensee referencing the AP1000 14 and the WCAP to determine that it was acceptably 15 protected.

16 MEMBER REMPE: I have a question. In the 17 report that Westinghouse submitted, they concluded that 18 chemical testing was not needed. Submergence testing 19 was not needed. And, they cited several reasons.

20 And, in the first reason they said was 21 because of a letter that ACRS wrote. And, you guys 22 actually mentioned that, too. But, nobody said, in 23 your letter, at least your draft, you didn't mention 24

42 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 that that didn't seem like a very good reference to 1

support that ACRS dismissed it.

2 And, I was a little offended that they would 3

even try and use that. Because I read what was in that 4

ACRS letter, it sure didn't support that you didn't 5

need that.

6 And, you're shaking your head yes, that 7

was a bad thing to do and I would have made the applicant 8

prove that sentence.

9 MR. TRAVIS: For that discussion on 10 chemical effects, you're correct.

11 MEMBER REMPE: Okay.

12 MR. MAKAR: What we did -- what we added 13 to that was the -- or in addition to that letter, there 14 were a phenomena identification and ranking table.

15 And then, a subsequent analysis which wasn't mentioned 16 in their topical report that addressed organic 17 materials from a variety of standpoints.

18 And so, they -- the reason that cable 19 materials haven't been included in our standard 20 chemical effects evaluations is because, as aa debris 21 material in and of themselves is they have fallen into 22 the category of uncertainty if you apply the accepted 23 methodology that's based on a lot of conservative 24

43 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 assumptions.

1 And, there are things that we don't know 2

about like cables and other materials whether they would 3

form a chemical precipitant or not.

4 Organic materials, including cables, have 5

been looked at in different ways. Now, from a chemical 6

resistance standpoint, they -- some of these materials 7

are chosen, for example, in the chemical process 8

industry because they have such good resistance to 9

chemicals and elevated temperatures at -- over a variety 10 of chemical conditions.

11 It could change with aging some, but 12 they're often a material choice for aggressive chemical 13 conditions.

14 What they are always -- the way they're 15 always included is from the acidification acids they 16 can generate under a radiation field in the post LOCA 17 environment.

18 And, that acid is then included in the 19 calculations that determine how much pH buffer one needs 20 in the containment.

21 From -- then there are other possible 22 contributors from the organics like agglomeration of 23 things that are in the water and whether that helps 24

44 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 you or hurts you from a debris generation and transport 1

standpoint.

2 And, also complexation. So, if these 3

materials from the -- if the organic materials can bind 4

with metallic ions or other things in the water, they 5

can increase the solubility which could mean less 6

precipitant.

7 So, we've looked at organic materials from 8

a variety of ways and I don't think that, you know, 9

the references we made didn't go into all that detail.

10 MEMBER REMPE: Yes. Well, again, I mean 11 there were several things they cited. It was just one 12 of them didn't seem to jive and I was surprised that 13 that wasn't disputed in your draft SE.

14 MEMBER RAY: Okay, I just -- before we go 15 off of this slide, because later on, my guess is as 16 someone was just mentioning, we're going to get into 17 things where we may forget the last point.

18 I just wanted to reiterate it, performance 19 of cables within the zone of influence, if any, is 20 outside the scope of the WCAP.

21 We're not trying to decide how much damage 22 23 MR. TRAVIS: That's exactly right.

24

45 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 MEMBER RAY: -- would result to cables 1

inside the zone of influence.

2 MR. TRAVIS: That's exactly right.

3 The staff's finding is based on at 4-D there 4

will be no damage to the cables.

5 MEMBER RAY: Yes.

6 MR. TRAVIS: Inside that 4-D, the WCAP 7

makes no finding.

8 MEMBER RAY: This is a -- the safety 9

evaluation is very thorough, very detailed, talks about 10 a lot of things which, based on rules like this, really 11 aren't relevant because they're talking about things 12 that, at the end of the day, are outside the scope of 13 what we're doing.

14 MR. TRAVIS: I'll just make a note real 15 quick that I think NEI 04-07, technically, you could 16 define the onset of incipient damage as your acceptable 17 ZOI. That's why I said the applicant chose to 18 conservatively define 4-D --

19 MEMBER RAY: Four instead of three.

20 MR. TRAVIS: -- or whatever.

21 MEMBER RAY: Yes.

22 MR. TRAVIS: I won't get into the numbers 23 in the open session.

24

46 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 But, yes. And so, that's why we were very 1

prescriptive in this determination.

2 MEMBER RAY: Yes.

3 MEMBER SKILLMAN: Can I ask this, please?

4 The gentleman from Vogtle announced that 5

this is an important action that we're undertaking here.

6 With regard to that last bullet, are we 7

in a zone of urgency where there are cabling activities 8

going on at Vogtle that hinge on the last bullet?

9 MR. TRAVIS: I definitely don't have the 10 expertise to answer that. Don, this project --

11 MEMBER SKILLMAN: That might be an 12 inappropriate question. But, what I'm wondering is 13 if there is a practical issue that is before us that 14 we don't fully recognize?

15 MEMBER RAY: Well --

16 MR. TRAVIS: Yes, we're going to --

17 MEMBER RAY: I don't --

18 MR. TRAVIS: We don't have anything on 19 that.

20 MEMBER RAY: I don't believe there is.

21 MEMBER SKILLMAN: I think the answer is 22 no, but that I've just seen some --

23 MEMBER RAY: Let's just assume for now the 24

47 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 answer's no. As I said, we were expecting to need to 1

get our part of this done this month, now is such that 2

we don't have to do it that quickly. That doesn't 3

answer your question, but proceed.

4 MR. TRAVIS: Okay.

5 So, on the next slide, I'll start talking 6

about WCAP item two which requests approval for the 7

use of the non-metallic insulation as a suitable 8

equivalent to the metal reflective insulation.

9 This approval is a -- would be at limited 10 locations and would be bounded by testing and analysis 11 as requested in the topical report.

12 I'll also, at a high level, note that the 13 approval of the blocks differs significantly from the 14 cables in that a single set of jet impingement testing 15 is not enough to qualify the blocks.

16 The blocks themselves require both testing 17 and analysis -- different types of testing and analysis 18 to all form of coherent justification for why they act 19 as a suitable equivalent.

20 And so, as part of the staff's review for 21 the non-metallic insulation blocks, we have served both 22 jet impingement and submergence testing, evaluated 23 thermal expansion testing performed by the applicant, 24

48 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 assessed the applicability of all the test facilities 1

at the affirmation test facilities.

2 Again, reviewed test materials and test 3

reports and issued a number of RAIs related to the 4

non-metallic insulation.

5 In further detail on this next slide, for 6

the qualifying the neutron shield blocks with regards 7

to jet impingement testing, they were tested to qualify 8

the ability -- their ability to withstand jet forces 9

under a variety of ZOIs and block configurations 10 including those both that they expected to be present 11 in the plant and perhaps were more conservative in those 12 expected in the plant.

13 This testing was then supported by a 14 discussion of confined jet behavior as based on their 15 location of the neutron shield blocks, it was not 16 obvious that a free jet was the appropriate model.

17 And so, the confined space of the reactor 18 cavity could have presented a compounding factor for 19 the jet pressure.

20 And so, to qualify that confined space, 21 the WCAP embarked on a literature review which the staff 22 reviewed for applicability.

23 And, ultimately the staff's finding for 24

49 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 jet impingement on the NMI was based on a combination 1

of the presented testing and the literature review for 2

confined space which allowed the staff to verify that 3

the predicted NMI jet impingement pressure would be 4

bounded by the test facility at the requested ZOI.

5 Ultimately, staff feels that the test 6

demonstrated the request nature of the blocks and showed 7

that in the actual plant, no debris would be generated 8

due to a jet at the ZOI expected.

9 On the next slide, the qualifying NMI also 10 required evaluation of chemical effects as the neutron 11

-- some of the neutron shield blocks are below the 12 containment flood up levels.

13 So, there's both a debris generation and 14 a submergence piece to this.

15 Submergence testing measured releases for 16 different levels of NMI encapsulation. Staff used the 17 testing as a means to evaluate that design's ability 18 to prevent chemical effects.

19 And, ultimately, the testing that the 20 applicant performed demonstrated and showed that a 21 complete encapsulation of the block was necessary to 22 prevent the release of any elements that could generate 23 chemical effects and that additional chemical effects 24

50 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 resulting from materials inside the non-metallic 1

insulation would be predicated on what the amount 2

submerged aluminum was present in containment.

3 And so, that led us on the next slide --

4 so the staff's finding is that the topical report 5

provides an acceptable technical basis for determining 6

that no debris will be generated by the blocks.

7 And, as there was no debris generated, the 8

blocks themselves functioned as a suitable equivalent 9

to MRI.

10 But, as part of this, staff imposed a pair 11 of limitations and conditions on this subset of the 12 WCAP.

13 The evaluation -- the staff's evaluation 14 of the NMI is limited to debris generation only, not 15 of their functions provided by the blocks such as the 16 neutron shielding. That ability would be assessed by 17 the supplicant on -- in the appropriate change process.

18 And, the staff also imposed a limit on the 19 amount of aluminum in containment based on the blocks 20 as the presence of additional aluminum combined with 21 the submergence effects from the blocks.

22 Basically, the applicant performed their 23 demonstration on the amount expected in the AP1000, 24

51 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 further aluminum could influence the chemical effects 1

generated from the submerged NMI.

2 And, for a discussion of the third request 3

in the WCAP, I'm going to toss it back to Clint.

4 MR. ASHLEY: Next slide, please?

5 So, this third item, the -- and it's the 6

final WCAP item, request approval to use the NEI 04-07 7

alternate evaluation methodology.

8 And this methodology is approved in the 9

Safety Evaluation associated with NEI 04-07 which was 10 done back in 2004 time frame.

11 But, the AP1000 plant design didn't 12 specifically invoke this section of the NEI 04-07 13 document. So, they wanted to be up front in this 14 topical report and show that they wanted to apply this 15 particular section of the 04-07.

16 So, the NEI 04-07 alternate methodology 17 in part assumes a double-ended guillotine break of the 18 postulated pipe breaks in the reactor coolant system 19 main coolant piping.

20 Unless that piping is physically limited.

21 And, it could be limited in a number of ways, piping 22 restraints, supports, other structural members of 23 piping stiffness that could be demonstrated by 24

52 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 analysis.

1 So, if you have this main coolant pipe that 2

is physically limited, the advantages that you can 3

assess a smaller break size for debris generation 4

purposes.

5 Next slide?

6 So, as far as the staff review approach 7

is concerned, we looked at the topical reports 8

implementation of the approved methodology.

9 We did focus our review on reactor coolant 10 system main piping breaks that are physically limited.

11 We audited calculations and reports used 12 to determine that limited separation for those 13 postulated breaks.

14

And, we also reviewed the WCAP's 15 methodology for determining essentially a result in 16 break diameter for limited separation breaks and the 17 associated zone of influence.

18 Next slide?

19 So, our finding, the applicant's approach 20 to determine limited separation breaks, equivalent 21 break diameter and zone of influence was reasonable 22 based on the information reviewed as part of the audit 23 and the information contained in the WCAP.

24

53 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 The WCAP does implement the alternate 1

evaluation methodology consistent with prior staff 2

approval. And, based on those two items, the WCAP's 3

use of NEI 04-07 alternate methodology was acceptable.

4 We did note that, because NEI 04-07 5

methodology, this alternate methodology, permits use 6

of operator actions or credit for non-safety systems, 7

that we wanted to avoid any confusion because the WCAP 8

excludes use of operator actions or used of credit for 9

non-safety systems as part of mitigation.

10 And so, we threw in this limitation and 11 condition just to make sure that was clear.

12 Next slide?

13 So, in summary the staff reviewed the three 14 items that were presented in the WCAP for review and 15 approval and they are summarized on this slide.

16 And, the draft Safety Evaluation, the staff 17 finds the approach described in the WCAP acceptable 18 and the staff approves the request subject to 19 limitations and conditions.

20 That concludes the staff presentation for 21 the public portion.

22 MEMBER RAY: Dana, this discussion here 23 today is only about what is the scope of the WCAP, not 24

54 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 broader issues. But, it does conclude -- reach a 1

conclusion about limitation on aluminum.

2 In the past, you suggested, I think, that 3

zinc is an equivalent to aluminum in some cases and 4

that it might be used in primer coating and so on.

5 MEMBER POWERS: It is used in the primer 6

coating. It is the primer for the epoxy and it is the 7

only coating on the upper part of the containment 8

building.

9 They don't -- they need the conductivity 10 through the containment shield, so they only use a 11 primer coating above a certain level. I can never 12 remember what that level is, but up in the higher dome 13 that's all there is.

14 It is -- I would not characterize it really 15 as equivalent to aluminum. It does form precipitates 16 in the water. They don't tend to be nearly as 17 flocculent and obnoxious as aluminum oxide 18 precipitates.

19 But, they do and so, but are they one to 20 one, I don't know. But, they are a consideration.

21 But, I believe those are taken into account 22 in the existing limitations in the -- for the GDC 191, 23 aren't they? I mean the --

24

55 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 MEMBER RAY: GSI.

1 MEMBER POWERS: GSI, I'm sorry.

2 MR. MAKAR: As a result of the methodology 3

that AP1000 uses for chemical effects analysis, it was 4

not required to evaluate zinc precipitants.

5 The staff hasn't really determined that 6

there are zinc precipitants that occur in the post LOCA 7

environment.

8 MEMBER POWERS: Well, if the staff hasn't, 9

then they're alone in the world because everybody knows 10 you get zinc precipitates in these things.

11 MR. MAKAR: Well, sorry, they were 12 observed not as in as many tests and the conditions 13 under which they occurred at weren't as you think.

14 MEMBER POWERS: Well --

15 MR. MAKAR: And, there were -- the quantity 16 wasn't as much. And so --

17 MEMBER POWERS: My thinking is that what 18 they really did was they took enough bromide in their 19 test solutions to bound not only the aluminum but 20 everything else that they can think of. Because 21 there's a lot of stuff.

22 MR. MAKAR: Say that again, please?

23 MEMBER POWERS: They --

24

56 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 MR. MAKAR: Enough --

1 MEMBER POWERS: In the WCAP where they 2

propose how to drove to resolve the generic safety 3

issue, they formulate a representative solution and 4

they put a lot of simulant materials in there.

5 One of the things they put in is bromide, 6

the other one I think silicon carbide for hard 7

particulates. But, it's not that they have any silicon 8

carbide in the plant, but they wanted to simulate a 9

hard particulate and fiber and a lot of things.

10 And, I think they took enough to simulate 11 what they thought was the amount of zinc that they would 12 get from, you know, blow downs and things like that.

13 MR. MAKAR: In some of the testing, the 14 zinc -- the precipitate was adherent also to the zinc 15 coupons rather than in the water.

16 And, that the --

17 MEMBER POWERS: That's the motion of time.

18 MR. MAKAR: And, again, the methodology 19 is based on if you take this conservative approach with 20 regard to aluminum and the other things that we were 21

-- that the industry was able to identify in the water, 22 the staff felt that that's conservative enough to 23 account for uncertainty about some other elements where 24

57 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 it wasn't clear what the precipitant was and what the 1

effect was on head loss.

2 MEMBER POWERS: Yes, there's --

3 MR. MAKAR: So, I think we -- there's --

4 zinc is -- it would be on the table if someone used 5

a different approach to chemical effects rather than 6

the standard methodology is one way of saying.

7 MEMBER POWERS: Yes, I would -- zinc 8

wouldn't be the first thing I would think of for chemical 9

effects because I don't believe they use triphosphate 10 in this system, do they?

11 MR. MAKAR: In this case, yes.

12 MEMBER POWERS: They do use it?

13 MR. MAKAR: Yes.

14 MEMBER POWERS: Oh God. That's really 15 bad.

16 MEMBER RAY: Well, I raise it here only 17 because, like I say, I don't want to increase the scope 18 of what we're trying to address here now because it's 19 important that we get closure on it ultimately.

20 But, because aluminum had been set up as 21 a consequence of what we're doing here, I felt I needed 22 to ask the question.

23 I don't think from what I've understood 24

58 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 of your dialogue here that we've answered the question 1

as to whether zinc is problematic, have we?

2 MEMBER POWERS: I think you try to bound 3

it with the amount of aluminum in there and it's not 4

going to be worse than aluminum.

5 At least my experience with zinc 6

precipitates is that they're pretty easy to handle.

7 Aluminum precipitates will -- are obnoxious in the 8

extreme.

9 So, if you put a lot of aluminum in, you're 10 okay. That would be my view on the thing.

11 MEMBER RAY: Well, I just want to give you 12 an opportunity to pursue it.

13 MEMBER POWERS: Yes, the -- but the --

14 MEMBER RAY: But, not --

15 MEMBER POWERS: -- issue of aluminum is 16 predominant in my mind as it -- aluminum, as they pointed 17 out, depends on how much you have submerged because 18 the submerged aluminum will corrode and you'll get more, 19 a lot more.

20 MEMBER RAY: Okay, well, I won't raise it 21 again then if you're satisfied.

22 MR. MAKAR: If I can just mention that also 23 with the AP1000, the strainer testing, and there was 24

59 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 bare strainers so that additional chemical effects 1

beyond what's considered in the design basis wouldn't 2

have had an effect. And, I think some of the fuel 3

assembly testing used higher levels that the design 4

basis and, the evaluation on the fuel.

5 So, it was conservative in a number of ways.

6 So, I think additional -- focusing on this conservative 7

methodology and staying within that design basis, staff 8

feels adequate to still to address those -- that kind 9

of uncertainty.

10 MEMBER RAY: Okay, questions?

11 MR. ROHATGI: Yes, just quickly, just a 12 clarification. The NMI has no aluminum, it's all 13 steel.

14 MR. MAKAR: There's no chemical effects 15 from the metal reflective insulation.

16 MR. ROHATGI: So, the aluminum thing is 17 not coming from NMI?

18 MR. MAKAR: That's correct.

19 MEMBER RAY: That's right.

20 MR. ROHATGI: Okay.

21 MEMBER RAY: Other questions?

22 (NO RESPONSE) 23 MEMBER RAY: Okay, it's five minutes after 24

60 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 2:00. So, we're going to make a transition here in 1

a moment into the closed session because I think it's 2

a little early, just an hour into this, to take a break.

3 And, we'll decide, depending on how the 4

closed session goes, whether we'll then take a break 5

during it or perhaps wrap up before need to.

6 So, if we can -- Westinghouse will Be the 7

first up in the closed session.

8 If Westinghouse can come up and, as they're 9

doing so, we'll invite any members here in the audience 10 of the public who will not be remaining with us if there 11 are any comments?

12 (NO RESPONSE) 13 MEMBER RAY: Seeing none, we will ask that 14 the phone line be opened so that we can make a similar 15 question to them.

16 Weidong, is it open and on?

17 MR. WANG: It is open.

18 MEMBER RAY: All right.

19 MR. WANG: All of -- yes, the line is open.

20 MEMBER RAY: Is there anyone on the phone 21 line who would like to make a comment on the discussion 22 that we've had here now?

23 (NO RESPONSE) 24

61 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 MEMBER RAY: Hearing none, we will close 1

the phone line and ask that staff and Westinghouse 2

ensure we have only the allowed participants.

3 Weidong, would you ensure the phone line 4

is closed, please?

5 And, with that, we will declare that we 6

are in closed session and ask Westinghouse to resume.

7 (Whereupon, the above-entitled matter went 8

into closed session at 2:07 p.m.)

9 10 11 12

1 Westinghouse Non-Proprietary Class 3

© 2018 Westinghouse Electric Company LLC. All Rights Reserved.

This presentation is non-proprietary AP1000 is a trademark or registered trademark of Westinghouse Electric Company LLC, its affiliates and/or its subsidiaries in the United States of America and may be registered in other countries throughout the world. All rights reserved. Unauthorized use is strictly prohibited. Other names may be trademarks of their respective owners.

Westinghouse Non-Proprietary Class 3

© 2018 Westinghouse Electric Company LLC. All Rights Reserved 2

WCAP 17938 Revision 2, ACRS Subcommittee - Public Meeting February 7, 2018 Andrew Pfister Shayan Sinha

3 Westinghouse Non-Proprietary Class 3

© 2018 Westinghouse Electric Company LLC. All Rights Reserved.

Background

AP1000 GSI 191 Design Bases AP1000 design significantly reduces / eliminates debris sources that are typically found in Generation II plants Maximum allowable fibrous debris inside containment is 6.6 lbs

- All fibrous debris is attributable to latent debris

- There is no fibrous debris generated during a LOCA Metal reflective insulation (MRI) is extensively used in containment DCD/FSAR provides requirements that must be demonstrated if an alternative (fibrous) insulation to MRI is utilized Insulation must be demonstrated to be a suitable equivalent insulation to MRI for the purposes of GSI 191 To qualify a suitable equivalent testing must be performed to demonstrate that debris will not be generated or transported Suitable equivalent testing must be approved by the NRC

4 Westinghouse Non-Proprietary Class 3

© 2018 Westinghouse Electric Company LLC. All Rights Reserved.

Background

WCAP 17938 Purpose Purpose of WCAP 17938 is to obtain approval of the following:

1.

Establish a ZOI applicable to all AP1000 plant in-containment cabling to demonstrate cabling will not generate LOCA debris 2.

Gain approval that the non-metallic insulation (NMI) utilized in the reactor vessel insulation systems (RVIS) is a suitable equivalent to MRI for the purpose of GSI 191 as applied in AP1000 3.

Gain approval to utilize the approved NEI 04-07 alternative methodology for defining debris generation break sizes for AP1000 Testing and analysis is complete to demonstrate that neither cabling nor NMI will contribute to post LOCA debris

5 Westinghouse Non-Proprietary Class 3

© 2018 Westinghouse Electric Company LLC. All Rights Reserved.

Background

WCAP 17938

• AP1000 cabling may contain fibrous and other materials that were not considered in initial GSI 191 debris source term evaluations

- Corrective actions included development of a test program to establish a zone of influence (ZOI) for in-containment cabling

• NMI is required in RVIS because subcomponents of the RVIS perform functions in addition to insulation (such as shielding and in-vessel retention support)

CA31 LNS Water Inlet Doors

6 Westinghouse Non-Proprietary Class 3

© 2018 Westinghouse Electric Company LLC. All Rights Reserved.

Summary of Results WCAP justifies no new debris generation for AP1000 from cabling or NMI

• Extensive large scale jet impingement testing established a ZOI for in-containment cables of 4 L/D

- Cabling ZOI design requirements were incorporated into the detailed design in advance of any cable or tray installation

• WCAP invokes the alternate evaluation methodology provided in NEI 04-07 to determine a limiting RCS break size in debris generation evaluation for certain AP1000 components

• Insights from NMI jet impingement and submergence testing resulted in strengthening design for elements of the RVIS

- Design was changed to use thicker and more robust encapsulation

Westinghouse Non-Proprietary Class 3

© 2018 Westinghouse Electric Company LLC. All Rights Reserved 7

Conclusions

8 Westinghouse Non-Proprietary Class 3

© 2018 Westinghouse Electric Company LLC. All Rights Reserved.

Conclusions

• Jet impingement testing supports a Cable ZOI of 4 L/D for AP1000 in-containment cabling

• Application of NEI 04-07 alternative break methodology is acceptable for AP1000

• Cabling does not contribute to AP1000 post LOCA debris limits

• Encapsulated NMI applications utilized within the AP1000 RVIS will not produce debris when subjected to jet impingement from limiting line breaks

• Neither cabling nor NMI within the RVIS contribute to GSI 191 chemical debris limits

• NMI utilized as part of the RVIS is a suitable equivalent to MRI for the purpose of GSI 191 WCAP justifies no new debris generation for AP1000 from cabling or NMI

Presentation to the ACRS Subcommittee Draft Safety Evaluation AP1000 In-Containment Cables and Non-Metallic Insulation Debris Integrated Assessment WCAP-17938-P, Revision 2 February 2018

Presentation Topics

• Introduction

• Overview

• Review Approach

• Finding

• Summary 2

Introduction

• NRC Technical Reviewers Clint Ashley Containment and Ventilation Branch Boyce Travis Containment and Ventilation Branch Renee Li Mechanical Engineering Branch Greg Makar Materials & Chemical Engr. Branch Malcolm Patterson PRA and Severe Accidents Branch

• NRC Project Manager Don Habib Licensing Branch 4 3

Introduction (contd)

• A topical report is a document that addresses a technical topic related to nuclear power plant safety.

• In topical report WCAP-17938, Westinghouse updates the AP1000 plant safety analysis related to Generic Safety Issue 191 (GSI-191).

• Westinghouse seeks review and approval of WCAP-17938 by the U.S. Nuclear Regulatory Commission (NRC) for use in the licensing process by AP1000 licensees.

4

Overview

• Main guidance for evaluating WCAP-17938:

Nuclear Energy Institute (NEI) 04-07, PWR Sump Performance Evaluation Methodology Safety Evaluation for NEI 04-07, PWR Sump Performance Evaluation Methodology WCAP-16530-NP-A, Evaluation of Post-Accident Chemical Effects in Containment Sump Fluids to Support GSI-191 5

Overview (contd)

• The AP1000 plant safety evaluation decision addressing GSI-191 is based on zero loss-of-coolant accident (LOCA) generated fibrous debris.

Achieved in part through the use of metal reflective insulation (MRI) or a suitable equivalent insulation.

As part of detailed design, the AP1000 plant uses a suitable equivalent insulation in three locations around the reactor vessel.

Use of a suitable equivalent insulation requires NRC review per the AP1000 DCD.

6

Overview (contd)

• The AP1000 plant design also includes electrical cabling that may be directly impinged upon by a loss-of-coolant accident jet.

AP1000 electrical cables may contain fibrous material that was not considered in the original GSI-191 debris source evaluation.

As a corrective action, Westinghouse conducted testing to define a zone of influence for cables.

7

Overview (contd)

• The AP1000 design basis in part states that a LOCA in the AP1000 does not generate fibrous debris due to damage to insulation or other materials included in the AP1000 design,

• As such, the WCAP seeks NRC approval for three items:

1. A zone of influence (ZOI) for electrical cabling in containment.

2. Use of non-metallic insulation (NMI) as a suitable equivalent to metal reflective insulation (MRI).*

3. Use of NEI 04-07 alternate evaluation methodology to assess debris generation.

• Next slide 8

Overview (contd)

To qualify as a suitable equivalent insulation, the AP1000 DCD states in part that:

Testing must be performed that subjects the insulation to conditions that bound the AP1000 plant conditions.

Testing demonstrates that debris would not be generated, to include chemical debris.

Testing and/or analysis must be approved by the NRC.

The three WCAP requests for NRC approval, are detailed on the following slides.

9

WCAP Item 1

• Requests approval for a ZOI for electrical cabling in containment.

• Staff review approach Observed cable jet impingement testing Assessed the applicability of the test facility Reviewed test materials Audited test reports Issued requests for additional information 10

WCAP Item 1

• Staff review approach (contd)

Staff reviewed observations from previous NRC visits to the test facility, and examined the facility conditions produced during instrumented tests These conditions were compared to facility conditions for current testing to verify repeatability Staff determined the facility produced conditions that would bound as-built facility conditions Applicant determined a ZOI for onset of damage, then conservatively requested an acceptable ZOI tested just beyond that showing no debris generation 11

WCAP Item 1

• Staff Finding The topical report provides an acceptable technical basis for determining that no debris will be generated by cables located at or beyond the proposed ZOI.

Because the WCAP demonstrated no debris generation outside the ZOI, the proposed ZOI for electrical cabling is acceptable.

• Limitations and Conditions Performance of cables within the ZOI (if any) is outside the scope of the WCAP.

12

WCAP Item 2

• Requests approval for the use of NMI as a suitable equivalent insulation to MRI.

• Staff review approach Observed jet impingement and submergence testing Evaluated thermal expansion testing Assessed the applicability of test facilities Reviewed test materials Audited test reports Issued requests for additional information 13

WCAP Item 2

• Staff review approach (contd)

Neutron shield blocks tested to qualify the blocks ability to withstand jet forces under variety of ZOIs/block configurations.

This testing was supported by a discussion of confined jet behavior, as reactor vessel cavity could be considered a confined space.

WCAP used a literature review, which staff reviewed for applicability.

Ultimately, combination of testing and literature review allowed for verification that the predicted NMI jet impingement pressure would be bounded by the test facility jet at the requested ZOI.

14

WCAP Item 2

• Staff review approach (contd)

Qualifying NMI as suitable equivalent also required evaluation of chemical effects.

Submergence testing measured releases for different levels of NMI encapsulation.

Staff used the testing as a means to evaluate the designs ability to prevent chemical effects.

Submergence tests showed complete encapsulation is necessary to prevent the release of elements that could generate chemical effects, and that additional chemical effects were predicated on amount of submerged aluminum.

15

WCAP Item 2

• Staff Finding The topical report provides an acceptable technical basis for determining that no debris will be generated by the blocks.

Because there is no debris generation, use of NMI as a suitable equivalent insulation to MRI is acceptable.

• Limitations and Conditions Evaluation limited to debris generation Limit placed on the amount of aluminum in containment 16

WCAP Item 3

• Requests approval to use the NEI 04-07 alternate evaluation methodology.

NEI 04-07 alternate evaluation methodology in part assumes a double-ended guillotine break of postulated pipe breaks in reactor coolant system (RCS) main loop piping unless physically limited by piping restraints, supports, other structural members or piping stiffness as may be demonstrated by analysis.

If physically limited, then a smaller pipe break size may be used to assess debris generation.

17

WCAP Item 3

• Staff review approach Evaluated the topical reports implementation of the approved methodology.

Focused review on RCS main loop piping breaks that are physically limited.

Audited reports used to determine the limited separation of the postulated breaks.

Reviewed the WCAPs methodology for determining the equivalent break diameter for limited separation breaks and the zone of influence (ZOI).

18

WCAP Item 3

• Staff Finding The applicant approach to determine limited separation breaks, equivalent break diameter and ZOI is reasonable based on information reviewed in the audit and contained in the WCAP.

The WCAP implements the alternate evaluation methodology consistent with prior staff approval.

Based on the above, the WCAPs use of the NEI 04-07 alternate methodology is acceptable.

• Limitation and Condition Excludes use of nonsafety systems and operators.

19

Summary

• The WCAP requests staff review and approval for three items:

the application of the proposed ZOI for cables the determination that NMI located in the reactor vessel cavity is a suitable equivalent insulation the application of the alternate evaluation for debris assessment

• The staff finds the approach described in the WCAP acceptable and approves the requests, subject to limitations and conditions.

20

BACKUP SLIDES 21

22 WCAP-16530 Methodology For Chemical Effects

• Calculates the amount of chemical precipitate calculated based on plant-specific materials and pH buffer Input the material quantities (e.g., aluminum surface area, fiberglass mass)

Input the pH buffer chemical Input realistic pH and temperature profiles Conservative corrosion/release rates applied

23 WCAP-16530 Methodology For Chemical Effects Released elements assumed to precipitate as certain chemical compounds

• AlOOH, NaAlSi3O8, Ca3(PO4)2 All precipitates present when the LOCA occurs All aluminum forms a precipitate All calcium forms a precipitate if phosphate is present Surrogate chemicals used in strainer and fuel assembly testing have been shown to clog fiber beds Refinements to the base model must be justified