ML20080N699
| ML20080N699 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 09/27/1983 |
| From: | Tucker H DUKE POWER CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8310060038 | |
| Download: ML20080N699 (2) | |
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DUKE POWER GOMPANY P.O. HOX 33180 CHAMLDTTE, N.C. 28242
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IIAL H. TUCKER
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TELEPHONE
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g g ; $$tember 27, 1983 SY/" "
Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission Region II' 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30303 Re: Catawba Nuclear Station Units 1 and 2 Docket Nos.50-413 and 50-414
Dear Mr. O'Reilly:
Pursuant to 10 CFR 50.55e, please find attached Significant Deficiency Report SD 413-414/83-10.
Very truly yours, d
Hal B. Tucker RWO/php Attachment cc: Director INP0 Records Center Office of Inspection and Enforcement Suite 1500 U. S. Nuclear Regu'iatory Commission 1100 Circle 75 Parkway Washington, D. C. 20555 Atlanta, Georgia 30339 NRC Resident Inspector Mr. Robert Guild, Esq.
Catawba Nuclear Station Attorney-at-Law P. O. Box 12097 Palmetto Alliance Charleston, South Carolina 29412 21351 Devine Street Columbia, South Carolina 29205 OFFICW" F310060038 830927 PDR ADOCK 05000 j
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CATAWBA NUCLEAR STATION REPORT NUMBER: SD 413-414/83-10 REPORT DATE: September 27, 1983 FACILITY: Catawba Nuclear Station Units 1 and 2
' IDENTIFICATION OF DEFICIENCY:
The Westinghouse NSSS 7300 Process Control Equipment NLP (Loop Power Supply) printed circuit cards which were shipped after August 1,1980
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and prior to September 1,1982 have a: deficiency in the adhesive bond of the heat sink assembly for the inverter transistors. The deficiency was identified by a Westinghouse technical bulletin dated June 15., 1983.
,3, INITIAL REPORT:
On-August 29, 1983, Virgil Brownlee of the NRC was notified of the deficiency by L. Coggins, J. Thomas, J. Smith, and C. Rolfe of Duke Power Company.
COMPONENT AND/0R SUPPLIER:
The-NLP printed circuit cards were supplied by Westinghouse's Industry Electronics Division.
DESCRIPTION OF DEFICIENCY:
The NLP Loop Power Supply cards have a. deficiency in the adhesive bond in the thermal link assembly of the heat' sink assembly on the inverter transistors. Failure of the adhesive bond allows the heat sink plate to come loose and fall off the printed circuit board.
ANALYSIS OF SAFETY IMPLICATIONS:
The heat sink plate is conductive and when it seperates from the 'NLP card K
it has the potential of creating various random failures by shorting out low ~ level signals in the card frame'. These short circuits within the SSPS my affect the safety of the plant.
CONNEC'iIVE ACTION:
There were 33 defective cards on Unit 1 (including 1 spare) and 36 defective cards on Unit 2.. These cards have been returned to Westinghouse for repair.
A new style heat sink assembly will be utilized which will eliminate the adhesive and make use of metal screws and an insulating shoulder washer to assemble the parts. These assemblies will be replaced by December l',1983.
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