ML20076A831
| ML20076A831 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 08/05/1983 |
| From: | Tramm T COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, 7103N, 83-09, 83-9, NUDOCS 8308180350 | |
| Download: ML20076A831 (2) | |
Text
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Commonwealth Edison
/
) one First N:ti'nal Plata. Chic;go. Illinois Address Reply to: Post Othee Box 767 Chicago, I!Iinois 60090 s
August 5, 1983 Mr. James G. Keppler, Regional Administrator
- Region III U.S.
Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137
Subject:
Byron Generating Station Units 1 and 2 Braidwood Generating Station Units 1 and 2 Process Protection System Heat Sinks and Relays NRC Docket Nos. 50-454, 50-455, 50-456, and 50-457
Dear Mr. Keppler:
On July 6, 1983, Commonwealth Edison notified Mr. James Konklin of a deficiency reportable pursuant to 10 CFR 50.55(e) regarding the Westinghouse 7300 process protection systems at Byron and Braidwood stations.
For your tracking purposes this deficiency was assigned number 83-09 for Byron and 83-09 for Braidwood.
This letter fulfills the thirty-day reporting requirement of the regulation.
DESCRIPTION OF DEFICIENCY The adhesive bond in the heat sink assembly on loop power supply (NLP) cards is subject to failure.
Failure of the bond can cause the separation of the heat sink plate from the thermal links such that it falls of f of the printed circuit board.
The second potential deficiency involves contact bounce as experienced in seismic testing of the temperature channel test (NTC) card.
This will result in signal saturation of the RTD Amplifier (NRA) card in the That and Tcold circuits.
The deficiency could delay initiation of the overtemperature - delta T and overpower-delta T trips.
ANALYSIS OF SAFETY IMPLICATIONS The heat sink plate is conductive metal and under certain circumstances could cause shorting of the low-level signal if it became wedged between cards in the card frame.
The relay chatter deficiency could delay initiation of the overtemperature-delta T and overpower-delta T trips as described above.
8308180350 830805 PDR ADOCK 05000454 S
PDR hhk do
J. G. Keppler August 5, 1983 CORRECTIVE ACTION The heat sinks on-the NLP cards will be replaced.
Installation at Byron Station is projected 'for the end of September,1983.
Installation at Braidwood Station is expected to be complete by the end of October, 1983.
Replacement relays for the NTC cards are being developed by Westinghouse.
If they are not installed prior to fuel load, existing filter circuits will be adjusted to compensate.
Please address questons regarding this matter to this office.
Very truly yours, fr N
T. R. Tramm Nuclear Licensing Administrator 1m cc:
Director of Inspection and Enforcement
.7103N
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