ML20005A369
| ML20005A369 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 06/19/1981 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8106300255 | |
| Download: ML20005A369 (2) | |
Text
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400 Chestnut Street Tower II l
June 19, 1981
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BLRD-50438/81-12 BLRD-50439/81-12 72
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Mr.
P. O'Reilly, Director jCU 3 7
Office of Insputir.st and Enforcement
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U.S. N ear Regulatory Commission
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Region II Suite 3100
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101 Mariett Street Atlanta, Geor 30303
Dear Mr. O'Reilly:
BELLEF(BITE NUCLEAR PLANT UNITS 1 AND 2 - CAPACITORS ON (X)NSOLIDATED CONTROL CORPORATION FIELD BUFFER CARDS - BLRD-50438/81-12, BLRD-50439/81 THIRD INTERIM REPORT The subject deficiency was initially reported to NRC-0IE Inspector M. Thomas on January 23, 1981, in accordance with 10 CFR 50.55(e) as NCR 1309 This was followed by our interim mports dated February 23 and May 27, 1981. Enclosed la our third interia mport. We expect to submit our next m port by January 12, 1982. We consider 10 CFR Part 21 to be applicable to this deficiency.
If you have any questions concerning this matter, please get in touch with t
D. L. Lambert at FT3 857-2581.
Very truly yours, TEleiESSEE VALLET AUTHORITY L. M. Mills, Manager Nuclear Regulation and Safety Enclosure
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co: Mr.VictorStallo,Jr., Director (Enclosure)/
Office of Inspection and Enforoceent U.S. Nuclear Regulatory Coensission Washington, DC 20555
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ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 CAPACITORS ON CONSOLIDATED CONTROL CORPORATION FIELD BUFFER CARDS BLRD-50-438/81-12, BLRD-50-439/81-12 THIRD INTERIM REPORT Description of Deficiency Field buffer cards (6N193-1) in the Solid-State control System (SSCS) are vendor supplied by Consolidated Controls Corporation. The card can be used interchangeably in both safety-related and nonsafety-related systems. Some field buffer cards have been experiencing failures of the capacitors on the cards, resulting in card failures.
Interim Progress Site inspections have been completed and all cards which have discrepancies have been identified.
Although only the 6N193 field buffer cards were cited as possibly deficient, additional cards used in the SSCS for Bellefonte units 1 and 2 were analyzed.
The capacitor's failure was because of a large inrush. current resulting from insertion of a card into a powered cabinet. A different type capacitoc (tantalum electrolytic) and a current limiting resistor were,
added to eliminate further failures.
Capacitors which were evaluated as unnecessary to circuit function were removed. This was the case for the 6N191, 6N193, and 6N196 cards.
As a result of their analysis, the vendor is undertaking an e:: tensive rework program on the 6N191, 6N193, and 6N196 cards, and they expect to provide TVA with an engineering report detailing their findings.
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