ML20207M619
| ML20207M619 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 01/09/1987 |
| From: | Diederich G COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 8701130234 | |
| Download: ML20207M619 (1) | |
Text
f Commonwealth Edison LaSalle Counh Nuclear Station Rural Rouc #1, Box 220 Mars,eilles lllinois61341 Telephone 815/357 6761 January 9, 1987 Mr. James G. Keppler Regional Administrator Region III U.S. Nuclear Regulatory Commission 199 Roosevelt Road Glen Ellyn, Illinois 60137
Dear Mr. Keppler:
This special report is being submitted in accordance with the C. W. Schroeder to J. G. Keppler letter dated December 22, 1983, regarding the LaSalle Unit 1 drywell temperature and revises the special report dated November 3, 1986, for this event.
On October 10, 1986 at 1630 hours0.0189 days <br />0.453 hours <br />0.0027 weeks <br />6.20215e-4 months <br />, it was observed that the thermocouple monitoring the "D" Main Steam Isolation Valve Limit Switch metal temperature was indicating 186.2*F.
This is above the 150*F temperature for which the qualified life was determined in accordance with procedure LTP-300-17T, EQ Trigger Setpoints. The ambient air temperature in the vicinity of the MSIV's averages around 130*F.
Following startup of Unit I after the Refuel outage, it was observed that the MSIV sensor was reading about 8'F higher than the previous operating cycle.
On October 4, 1986, a drywell entry was made and a small gap in some insulation on the "D" Main Steam Line was closed. The sensor initially showed l
a 15'F decrease after the gap was closed. However, several hours later the l
temperature increased to between 180'F and 195'F and has remained in this l
range. On December 5, 1986 the cause of the high metal temperature was determined to be from a packing leak on the "D" MSIV.
The packing leak has not yet been corrected, but will be repaired at the first available opportunity.
An analysis by Sargent and Lundy for the MSIV limit switch seals shows that for a postulated continuous temperature of.300*F, the qualified life is 169 days.
l The station will replace the MSIV limit switch equipment before the end of the qualified life.
8701130234 870109 AO-gDR ADOCK 05000373 G. J. Diederich PDR Station Manager LaSalle County Station GJD/KC4/sga Y
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