ML17328A508
| ML17328A508 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 10/19/1990 |
| From: | Alexich M INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG |
| To: | Murley T NRC, NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| AEP:NRC:1059A, NUDOCS 9010260213 | |
| Download: ML17328A508 (5) | |
Text
ACCELERATED DI~)TPJBUTION DEMONSTPWTION SYSTEM REGULA Y INFORMATION DISTRIBUTI SYSTEM (RIDS)
L.'CCESSION NBR:9010260213 DOC.DATE: 90/10/19 NOTARIZED: NO DOCKET FACIL:50-316 Donald C.
Cook Nuclear Power Plant, Unit 2, Indiana a
05000316 AUTH.NAME AUTHOR AFFILIATION ALEXICH,M.P.
RECIP.NAME RECIPIENT AFFILIATION MURLEY,T.E.
NRC No Detailed AffiliationGiven
SUBJECT:
Discusses statys of util thimble tube testing program initialy committed to in util 881026 ltr.
DISTRIBUTION CODE:
AOOID COPIES RECEIVED:LTR L ENCLN SIZE'ITLE:
OR Submittal:
General Distribution NOTES:
D RECIPIENT ID CODE/NAME PD3-1 LA COLBURN,T.
INTERNAL: NRR/DET/ECMB 9H NRR/DST 8E2 NRR/DST/SICB 7E NUDOCS-ABSTRACT OGC/HDS1 RES/DSIR/EIB EXTERNAL: NRC PDR COPIES LTTR ENCL RECIPIENT ID CODE/NAME PD3-1 PD 01 NSIC NRR/DOEA/OTSB11 NRR/DST/SELB 8D NRR/DST/SRXB 8E OC REG FILE COPIES LTTR ENCL D
D R
D NOTE TO ALL"RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAMEFROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!
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LTTR 17 ENCL
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Power Company ~
P.O. Box 16631 Coiumbus, OH 43216 AEP:NRC:1059A Donald C.
Cook Nuclear Plant Unit 2 License No.
DPR-74 Docket No. 50-316 THIMBLE TUBE TESTING PROGRAM U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington; D.C.
20555 Attn: T.
E. Murley October 19, 1990
Dear Dr. Murley:
In our letter AEP:NRC:1059 dated October 26,
- 1988, we committed to provide a thimble tube testing program for Unit 2 based on eddy current results obtained during our summer 1990 refueling outage.
This letter identifies our program to examine the Unit 2 thimble tubes in the future.
The Unit 1 thimble tube testing program will be provided at a later date as promised in AEP:NRC:1059.
On August 29,
- 1990, we met with members of your staff to discuss the results of the Unit 2 summer 1990 eddy current test.
The proceedings of that meeting are summarized in a memorandum to our docket by Mr. Timothy Colburn of your staff dated September 13, 1990.
At that meeting, we presented evidence of apparent "accelerated" wear of the Unit 2 thimble tubes.
After one cycle of operation with newly installed thimble tubes, ten thimble tubes were worn enough, including one failure, to warrant replacement.
Nineteen additional tubes were worn enough to warrant repositioning to realign wear surfaces to a location which is free of wear.
In addition, we committed:
1)
To replace ten thimble tubes and axially reposition 19 other thimble tubes; 2)
To re-examine all Unit 2 thimble tubes during the next refueling outage, currently scheduled for winter 1992;
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Dr. T.
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~ Murley AEP:NRC:1059A 3)
To consider re-examining Unit 2 thimble tubes prior to the next refueling outage if an outage of sufficient duration were to occur prior to the next refueling outage and if the results of Unit 1 eddy current testing or Unit 2 operational experience indicated that such an earlier re-examination of Unit 2 thimble tubes would be warranted; 4)
To provide the staff with Unit 1 eddy current test results following the upcoming Unit 1 refueling outage; and 5)
To provide the staff with the results of our root cause analysis and long-term recommendations which we indicated would be completed in early 1991.
Since that meeting, the ten thimble tubes have been replaced and 19 thimble tubes have been repositioned.
Also, each of these 29 thimble tubes were eddy current tested to provide baseline information for subsequent examination's.
I We are still evaluating the root cause of our thimble tube wear.
Our root cause analysis is on'hold until we examine the Unit 1 thimble tubes.
Comparison of the Unit 1 wear data with the Unit 2 data should provide adequate insight to the nature of our thimble tube wear problems.
Finally, with regard to a Unit 2 thimble tube inspection program, we will fulfillour commitments as outlined above.
In addition, we will continue to re-examine the Unit 2 thimble tubes and replace or reposition thimble tubes as is necessary during each refueling outage until cyclic wear rates are reduced to reasonable levels as a
result of an engineered long-term solution to this problem.
At that time, this inspection program will be reviewed and, if necessary or
- prudent, revised.
We will inform you of any such change.
This document has been prepared following Corporate procedures that incorporate a reasonable set of controls to ensure its accuracy and completeness prior to signature by the undersigned.
Sincerely, M. P.
A xich Vice President ldp cc:
D. H. Williams, Jr.
A. A. Blind - Bridgman J.
R. Padgett G. Charnoff A. B. Davis
- Region III NRC Resident Inspector
- Bridgman NFEM Section Chief
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