ML20079B859
| ML20079B859 | |
| Person / Time | |
|---|---|
| Site: | Columbia, Satsop  |
| Issue date: | 06/10/1991 |
| From: | Sorensen G WASHINGTON PUBLIC POWER SUPPLY SYSTEM |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| REF-PT21-91 067, 67, GO3-91-082, GO3-91-82, NUDOCS 9106180024 | |
| Download: ML20079B859 (7) | |
Text
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WASillNGTON PUllLIC POWER SUI'l'LY SYSTEM l'.O Das 1223 e 11rrsa. histrigstart tr45-l!.1223 e (2(6) 882 o 128 June 10. 1991 G03-91-082 Docket No. 50-508 U.
S.
Nuclear Regulatory Commission Attention:
Jocument Control Desk Mail Station P1-137 Washington, D.
C.
20555 i
Subject:
NUCLEAR PROJECT No. 3 POTENTIAL 10CFR50.55(E) DEFICIENCY WESTING 110USE POWER CENTER DRY TYPE TRANSFORMER INSUIATOR CRACKING on May 13, 1991, the Supply System notified your offico of a potential 10CPR50.55(o) deficiency concerning the subject condition.
Attached is a Supply System Interim Report.
The report provides a description of the deficiency, correctivo actions taken/ planned, and the current status.
To-date, the Supply System does not have suf ficient information to fully determino reportability under 10CFR50.55 (o).
In addition, while it is known that this same type of transformer has been supplied to other projects, the generic significanco has not been determined.
This written report is being submitted pursuant to earlier oral notification.
If our evaluations determine that the subject condition is reportable, the Supply System will submit the appropriate report to describe the plan of correctivo action.
As our investigation continues, if significant new information is developed, Interim Reports may be filed prior to tho datormination I
l of final reportability, l
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S. Ituclear Regulatory Commission Page Two POTENTIAL 10CFR50.55(E) DEFICIEllCY WESTINGHOUSE POWER CENTER DRY TYPE TRANSFORMER INSULATOR CRACKIllG Should you have any questions or desire further information, pleano contact Mr.
C. M. Dutros, WNP-3/5 Site Manager at (206) 482-4428, Ext. 5010.
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G.
C. So'ronson, Manager Regulatory Programs WKD/cae ces Mr. R. G.
Dailey, Puget Sound Power & Light Co.
Mr. W.
L.
Bryan, Washington Water Power Co.
Mr. R. E.
Dyer, Portland General Electric Co.
Mr. J. R. Lewis, BPA Mr. T. A. Lockhart, Pacific Power & Light Co.
Ms. R. M. Taylor, Ebasco - Elma Ebasco - New York Mr. J.
D. Martin, U.
S.
NRC, Region V Administrator Mr. H. S.
Reynolds, Winston & Strawn f
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i WASHINGTON PUBLIC POWER SUPPLY SYSTEM WNP-3 i
1 INTERIM REPORT i
WESTINGHOUSE POWER CENTER DRY TYFE TRANSFORMER INSULATOR CRACKING (CONTRACT NO. 3240-48)
DEVIATION / NONCOMPLIANCE NO 067 i
6 Prepared by:
C G Reid @NzC
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Date:
June 5, 1991 l'
s 4
I i
o WASHINGTON PUBLIC POWER SUPPLY SYSTEM NUCLEAR PROJECT N0. 3 INTERIM REPORT Westinghouse Powe'r Center Dry Type Transfomer Insulator Cracking Deviation / Noncompliance ha. 67 Introduction This Interim Report is submitted pursuant to the requirements of 10CFR50.55(e).
It concerns the d'"./ery of cracked coil support insulators in Class IE and Non Class IE dry +yr puwer center transformers supplied to WNP-3 by Westinghouse Electric Corpo,'a,1on. Preliminary assessment indicates that the cracking is caJed by stress placed on the insulators as a result of their off center positioning between the pressure plate and the transfome r coil.
The compressive forces that hold the transformer coils in position act through these l
insulators.
The cracked insulators have been found in both energized transformers at.] ones which have never been energized.
The transformers are type ASL Core Form Power Center Transformers, rated between 750KVA and 2666KVA, with primary voltage of either 13.8KV or 4.16KV and secondary voltage of 480V, This deficiency has been designated as potentially reportable since the detemination of significance could not be completed within 14 days of QA notification as required by procedure.
Significance and reportability will be decided and a Final Report submitted when information is received from the manufacturer and significance can be determined.
On May 13, 1991 Lewis Miller of the Region V Office was notified of this problem by telecon.
Description of problem in September 1987, an insulator that supports the C-phas'e coil of a Westinghouse
. supplied (Contract 3240-48) dry type air ventilated 2000KVA Non Class IE transformer (A22-NA) was discovered to be cracked and this problem was documented on a work request.
Then in January 1990, three (3) cracked insulators were discovered in Non Class IE transformer A21-NA purchased under the same contract.
The latter discovery resulted in an engineering inspection of transformers A21-NA and A22-NA.
The inspection confirmed the insulator cracking and also identified the off-center positioning of the insulators between the coil and the pressure plate.
Preliminary assessments indicated that the cracks resulted from the stress caused by the compressive force acting through the side of each insulator (see Sketch A).
Both these transformers were energized prior to the discovery of the cracked insulators.
As a result of this discovery, a letter was sent to Westinghouse in February 1990 notifying them of the problem and requesting their technical assistance.
. ~
a Deviation / Noncompliance No. 67 Pago 2 Description ofPrnblem(Cont'd)
Due to the above, Engineering initiated an additional work request to open the Plant's six (6) Class IE power center transformers, purchased under the same contract, for inspection.
The transformers, which have not yet been energized, were inspected in November 1990.
This inspection found that the Class IE transformers had the same off center positioning of the insulators between the transformer coil and the pressure plate.
In addition, cracked insulators were found in two of the six transformers ( A33-SA and B33-58).
Westinghouse was
. advised of this subsequent discovery.
No information or assistance was provided 4
by them and on April 11,1991. NCR 15525 was initiated to document and track resolution of the problem and the open work requests were closed.
The problem was deemed potentially significant since it is unknown at this time what effect the insulator's off center position and subsequent cracking would have on the Class IE qualification of the transformers.
This evaluation will begin when inf ormation requested from Westinghouse, in our letter of April 30, 1991 and earlier correspondence referenced therein, is received.
Corrective Action The Project has tracked this problem from an isolated finding to what appears to be a generic problem.
After it was detemined that the problem affected our Class IE transformers, NCR 15525 was written to document the deficiency and track resolution. As part of the NCR's interim disposition and evaluation, the finding was deemed potentially significant since the potential for common mode failure exists and potentially reportable to the NRC under 10CFR50.55(e) as required by Procedure C3-N-23WP when significance could not be evaluated within 14 days.
When the requested technical information is received from Westinghouse, significance will be determined and a final disposition will be made on the NCR to resolve this problem.
Current Status i
The Project formally notified Westinghouse Electric Corporation on Ar : 1 30, i
1991 that this problem affects our Class IE transformers as well a.
the Non Class IE transformers and asked for technical assistance to evaluate it.
We also informed Westin under 10CFR50.55(e) ghouse that we would be reporting this problem to the NRC and requested they evaluate the need for a 10CFR Part 21 Report since the defect appeared generic to the product and the Project has no l
schedule for resolution at this time.
The Project has not yet received a response from Westinghouse.
i Final Report Due to the currently undefined schedule for Westinghouse technical input and Preservation Period limitations that prevent Supply System resolution of this l
issue without vendor input, the schedule for issuance of a Final Report can not be determined.
Additional Interim Reports will be filed if significant new information develops.
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2 W ASHlhCTON POOLIC POW 4R SUPPLY SYSTEM INTEROFFICE MEMORANDUM E3-JLP-91-060
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DISTRIBUTION: KAll DROP:
DATI:
June 5. 1991 JP Cooper 775 BJ Crow 772 C. M. Butros, WNP-3/5 Site Manager (760)
WK Drinkard 701 Tch LA Hill 772 J. L. Perreault, WNP-3 Technical Mgr. (751)
RJ Marzano 752 ruoM CG Reid 714 DELEGATION OF AUTHORITY JW Rett 757 sulUECT:
RM Taylor 705 ADMIN FILE 060 WNP-3 FILE 703
REFERENCE:
JLP/lb 751 Dic 20.3 Mr. C. M. Butros will have delegation f or the duties of the WNP-3 Technical Manager during my absence June 6.1991 and June 7,1991.
Mr.
Butros will have full responsibility of this position except for personnel matters and salary action.
/cae tVP-102 R5 to 90)
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