ML17328A797
| ML17328A797 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 11/27/1990 |
| From: | Alexich M INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG |
| To: | Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| AEP:NRC:1059B, NUDOCS 9012040160 | |
| Download: ML17328A797 (5) | |
Text
.-ACCELERATED D TRIBUTION DEMONS TION SYSTEM REGULATORY INFORMATION DISTRIBUTXON SYSTEM (RIDS)
ACCESSION NBR:9012040160 DOC.DATE: 90/11/27 NOTARIZED: NO DOCKET FACIL:50-315 Donald C.
Cook Nuclear Power Plant, Unit 1, Indiana 05000315 AUTH.NAME AUTHOR AFFXLIATION ALEXICH,M.P.
Indiana Michigan Power Co. (formerly Indiana
& Michigan Ele RECXP.NAME RECIPIENT AFFILIATXON MURLEY,T.E.
Document Control Branch (Document Control Desk)
SUBJECT:
Forwards results of eddy current exam of thimble tubes during 1990 refueling outage
& tube testing program.
DISTRIBUTXON CODE A001D COPIES RECEIVED LTR ENCL SIZE:
TITLE: OR Submittal:
General Distribution NOTES RECIPIENT ID CODE/NAME PD3-1 LA COLBURN,T.
INTERNAL: NRR/DET/ECMB 9H NRR/DOEA/OTSBll NRR/DST/SELB 8D NRR/DST/SRXB 8E OC/LF+9 RE~X"L 01 EXTERNAL: NRC PDR COPXES LTTR ENCL 1
1 2
2 1
1 1
1 1
1 1
1 1
0 1
1 1
1 RECIPXENT ID CODE/NAME PD3-1 PD NRR/DET/ESGB NRR/DST 8E2 NRR/DST/SICB 7E NUDOCS-ABSTRACT OGC/HDS1 RES/DSXR/EXB NSIC COPIES LTTR ENCL 1
1 1
1 1
1 1
1 1
1 1
0 1
1 NOTE TO ALL"RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM P 1-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!
- TOTAL NUMBER OF COPIES REQUIRED:
LTTR 18 ENCL 16
indiana hlgchigan ~
Power Company ~
P.O. Box 16631 Columbus, OH 43216 R
AEP: NRC: 1059B Donald C.
Cook Nuclear Plant Unit 1 Docket No. 50-315 License No.
DPR-58 RESULTS FROM EDDY CURRENT EXAMINATIONOF THIMBLE TUBES DURING 1990 REFUELING OUTAGE AND THIMBLE TUBE TESTING PROGRAM U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C.
20555 Attn: T. E. Murley November 27, 1990
Dear Dr. Murley:
At an August 29, 1990 meeting with members of your staff to discuss the results of the Unit 2 summer 1990 eddy current examination of the thimble tubes, we committed to provide the results of the Unit 1 autumn 1990 thimble tube eddy current examination.
Also, in our letter AEP:NRC:1059 dated October 26,
- 1988, we committed to provide a thimble tube testing program for Unit 1 based on eddy current results obtained during the autumn 1990 refueling outage.
These items are included in this letter.
Attached is a summary of the results from the Unit 1 autumn 1990 eddy current examination.
After operating for only one cycle after being replaced, some amount of wear was found on 56 of the 57 thimble tubes.
One tube could not be replaced during the previous refueling outage; its location was capped during Cycle 11 operation and therefore no data is available for the 58th thimble tube.
The maximum amount of wear found in one tube was 64%.
As was noted for the Unit 2 thimble tubes, the worst wear on the majority of the tubes is found at locations corresponding to the fuel assembly bottom nozzle.
During the current refueling outage, we will reposition the 29 thimble tubes that have wear indications in excess of 30% to realign wear surfaces to a location which is free of wear.
No tubes will be replaced as the indications for all tubes are below the value provided by Westinghouse Electric Corporation in their finite element analysis of the Cook Nuclear Plant thimble tubes.
9012040160 901127 PDR ADOCK 05000315 P
PDC one
Dr. T. E. Murley AEP:NRC'1059B Again, as noted in our letter AEP:NRC:1059A dated October 19,
- 1990, we are still evaluating the root cause of our thimble tube wear.
In the August 29, 1990, meeting we committed to provide the staff with the results of our zoot cause analysis and long-term recommendations, both of which we indicated would be provided in early 1991, Finally, with regard to a Unit 1 thimble tube inspection program, we will continue to re-examine the Unit 1 thimble tubes and replace or reposition thimble tubes as 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 program is identical to the Unit 2 thimble tube inspection program provided to you in our letter 'AEP:NRC:1059A.
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 exich Vice President ldp Attachment cc:
D, H. Williams, Jr, A. A. Blind - Bridgman J.
R. Padgett A. B. Davis - Region III NRC Resident Inspector
- Bridgman NFEM Section Chief
ATTACHMENT TO AEP:NRC:1059B
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