ML11356A028
| ML11356A028 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 09/10/2009 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Atomic Safety and Licensing Board Panel |
| SECY RAS | |
| Shared Package | |
| ML11356A026 | List: |
| References | |
| RAS 21601, 50-247-LR, 50-286-LR, ASLBP 07-858-03-LR-BD01 | |
| Download: ML11356A028 (10) | |
Text
RIV000030 Submitted: December 22, 2011 EXCERPT 1
UNITED STATES OF AMERICA 2 NUCLEAR REGULATORY COMMISSION 3 + + + + +
4 565TH MEETING 5 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 6 (ACRS)
+ + + + +
THURSDAY, SEPTEMBER 10, 2009 1 + + + + +
1 ROCKVILLE, MARYLAND 12 The Advisory Committee met at the Nuclear 13 Regulatory . Commission, One White Flint North, 14 Commissioner's Conference Room, 11555 Rockville Pike, 15 at 8:30 a.m., Dr. .Mario V. Bonaca, Chairman, 1 COMMITTEE MEMBERS:
MARIO V. BONACA, Chairman 1 SAID ABDEL-KHALIK,. Vice Chairman GEORGE E. APOSTOLAKIS, Member 2 J. SAM ARMIJO, *Member-at-Large 22 SANJOY BANERJEE, Member 23 CHARLES H. BROWN, Member 24 MICHAEL L. CORRADINI, Member 25 OTTO L. MAYNARD, Member NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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2 2 COMMITTEE MEMBERS (Continued):
3 DANA A. POWERS, Member 4 HAROLD B. RAY, Member 5 MICHAEL T. RYAN, Member 6 WILLIAM J. SHACK, Member JOHN D. SIEBER, Member 8 JOHN W. STETKAR, Member 9
10 1
12 13 14 15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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3 1 C-0-;*N-T-E-N-T-S 2 Call to Order and Welcome .......................... 4 3 Indian Point License Renewal ....................... 7 4 Briefirig/DiscusSion with NRC Staff*~************ 83 5 Entergy Response to Questions ..................... 94 Public Comments ........ *.......................... 113 License Renewal Application ...................... 117 and Final SER for the Three Mile Island Nuclear Station Unit 1 Briefing/Discussion with NRC Staff.; ........... 118 1 Fire Protection for Nuclear Powerplants . . . . . . . . . . 17 5 1 Draft Digital Instrumentation and 13 Control Research Plan for 14 Fiscal Years 2010 to 2014 . . . . . . . . . . . . . . . . . . . . . . . . 211 15 Adjourn 16 17 18 1
20 21 22 23 24 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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90 1 Thank you.
2 MS. GREEN: I would like to move on to the 3 flow-accelerated corrosion program and the operating 4 experience.
5 During the ACRS Subcornrni ttee :rp.eeting in 6 March, an ACRS member questioned why the inspection frequency did not change for instances where the minimum measured wall thickness was near or below minimum acceptable wall thickness. At. that time, the 10 staff did not answer the ACRS member's question. So I 11 would like to try to address-that now.
12 During the audit, the staff questioned the 13 applicant about the incidences of wall thinning that 14 were reported in the license renewal application.
15 Specifically, there was an IP3 vent chamber drain 16 piping, IP3 high-pressure turbine drain piping. There 1 is a 2-inch diam~ter line and a three-quarter-inch diameter line, and the IP2 steam trap piping. These 1 were, I think, the four cases that the ACRS member was referring to in the staff's audit report.
2 In response to the audit question, as well 22 as a few others that were related to the flow-23 accelerated corrosion program, the applicant stated 24 that the piping and affected components were included 25 in the flow-accelerated corrosion program prior to the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323RHODE ISLAND AVE., N.W.
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91 insp~ctions. As the wall thinning of these components 2 was discovered, the applicant replaced the 'components 3 with like-for-like materials *or FAC-resistant 4 materials.
5 The applicant also stated that, if a component is discovered that has a current or projected wall thickness less than the minimum acceptable wall thickness, then additional inspections 9 of identical or similar piping components in a 10 parallel or alternate train is performed to bound the 1 extent of thinning. When the inspections of 12 components detects significant wall thinning, then the 13 sample size for that line is increased.
14
- One of the examples I would like to talk 15 about to explain this is the IP3 vent chamber 16 drainpipe thinning. During the refueling outage '13, Entergy did an inspection of an elbow immediately downstream of the moisture separator reheater and 1 found wall thinning less than the minimum acceptable 2 wall thinness, requiring replacement of the elbow.
2 Based on the results of that inspection, 22 the applicant performed a sample expansion to 23 determine the extent of condition for this pipe 24 thinning. The expansion included corresponding 25 components on the other moisture separator reheaters NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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92 with a configuration similar to that of the elbow 2 displaying the thinning.
3 Entergy then performed four additional inspections. These inspections also found wall thinning less than the minimum acceptable thickness requiring replacement of the components.
The sample expansion was continued until no additional components .were detected with significant** wear. Entergy performed four additional 1 inspections downstream of the worn elbows. .The 1 results . of this expansion did not find significant 12 wear, and the sample expansion was then terminated by 13 Entergy. The applicant updated and adjusted the 14 Checkworks model to incorporate the inspe~tion data.
MEMBER BROWN: Before you go on, I guess I asked that question. So I will ask it again.
I'm trying to draw a conclusion from your answer that, No. 1, they replaced them with more erosion-resistant or flow-accelerated corrosion-resistant materials when they did the replacements.
Is that correct?
22 MS. GREEN: For that particular line, they 23 were planning to replace with Chrome-Moly, but for 24 other lines 25 MEMBER BROWN: That doesn't mean anything; NEAL R. GROSS COURT REPORTERS AND ~SCRIBERS 1323 RHODE ISLAND AVE., N.W.
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93 1 I'm not a metallurgist. Is it better or worse?
2 MS.. GREEN: It 1 s better.
3 MEMBER BROWN: Okay. Thank you.
4 MS. GREEN: Sorry.
5 That is more FAC-resistant. For other 6 lines, they did a replacement of like-for-like material.
8 MEMBER BROWN: Okay. The second question 9 was they had found the wall thicknesses considerably 10 less. There were a number of other locations also 11 that had less than the minimum acceptable wall 12 thickness.
13 So the second part of the question about, 14 if they just did it like-for-like, what do you do to 15 your inspection process to make sure you don't 16 encounter a circumstance that you now find you've got 17 less than minimum wall thickness again, which means 1 increased frequency? That part I didrt' t understand 19 the answer. Or was there an answer?
20 MS. GREEN: I am not a flow-accelerated 2 corrosion program expert. So I would have to ask Matt 22 Yoder from the staff to address your question.
23 MEMBER MAYNARD: I believe we have 24 somebody coming to answer that.
25 We need a portable microphone, I believe.
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94 MR. YODER: Okay, Matt Yoder, NRR staff.
2 So, when these instances were found, the 3 data is then fed back into your Checkworks model. So 4 that, for future planning of inspections and UT, your 5 model is _going to predict a gr~ater wear rate at those 6 locations, and it should then be scheduled for more frequent UT inspection.
MEMBER BROWN: Okay. So there was an explanation of the Checkworks thing in, I think, the applicant's answer back, which I read, not being a, 12 So the point being that the information of 13 the increased wear* rate is then fed back into this 14 model, so that it gets into a periodic inspection that 15 is more frequent than before? It is not like you go 1 change a chart somewhere, but you do it based on the 17 predictions of the model?
18 MR. YODER: That is correct. The model is 19 continuously updated with actual field data.
20 MEMBER BROWN:> Okay. All right, thank 2 you.
22 MEMBER SHACK: How long has the Checkworks 23 program been in place at Indian Point?
24 MR. YODER: I will _have* to defer to 25 Entergy.
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95 MR. AZEVEDO: My name i::'? Nelson Azevedo.
.2 I'm the Supervisor of Programs at Indian Point.
3 We first started using the Checkworks 4 models when it was first issued by EPRI, which I 5 believe was the early nineties. I don' t know the 6 exact date.
MEMBER SHACK: It hasn't. reached steady-state yet?
MEMBER MAYNARD: Okay, let's go.
MS. GREEN: Okay. I would just like to cover briefly the staff's evaluation of the 12 applicant's flow-accelerated corrosion program.
13 In the license renewal application, the 14 applicant stated that its flow-accelerated corrosion 15 program is consistent with the GALL AMP XI .M17 with 1 one exception, that exception being the use of EPRI 1 NSAC-202L, Revision 3, in lieu of Revision 2, which is 1 recommended in the GALL report. The staff reviewed 1 the exception and found that the use of Revision 3 is acceptable.
2 Based on. the staff's audit and review, it 22 determined that all other program elements are 23 consistent with the GALL report AMP.
2 The applicant's program includes updated 2 inputs for the power operating parameter changes with NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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96 1 steam flow rates and temperatures and such. It also 2 identified piping systems and components that are 3 currently the most susceptible to the loss of material 4 due to FAC.
5 Corrective actions that are in place 6 include re-evaluati9n, repair, or replacement. Based on the review of the applicant's program, the staff concluded that it is adequate to manage the effects of aging, and therefore, acc~ptable.
During the March ACRS Subcommittee, ACRS 1 Member Brown asked the staff to explain the various 12 criteria for Charpy upper-shelf energy. At the time, 13 the staff did not provide a full explanation, and 1 therefore, *chairman Maynard asked us to provide an 15 explanation of the criteria, which I will attempt to 16 do now.
1 10 CFR 50, Appendix G, requires that 18 reactor vessels must maintain Charpy
- upper-shelf 19 energy values of no less than 50-foot- pounds, unless 20 it can be demonstrated that lower values of upper-2 shelf energy will provide margins of safety against 22 fracture equivalent to those required by Appendix G of 23 Section 11 of the ASME Code.
24 Appendix K of the ASME Code, Section 11, 25 and ASME Code Case N-512 provide criteria for NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE, N.W.
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