ML20151R362
| ML20151R362 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 08/02/1988 |
| From: | Diederich G COMMONWEALTH EDISON CO. |
| To: | Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 8808120142 | |
| Download: ML20151R362 (2) | |
Text
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Comm:nwrith Edison LaSalle Coun'.y Nuclear Station RuralRoute #1, Box 220 Marseilles, Illinois 61341 TWohone 815/357 6761 August 2, 1988 r p;tf 0RITY ROUTIn hyp tuU y
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Mr. A. Bert Davis
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v Regional Administrator hklAg f Region III i
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U.S. Nuclear Regulatory Commission FILE A
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799 Roosevelt Road Glen Ellyn, Illinois 60137 This special report is being submitted in accordance with Technical Specification 3.7.7.a and the C. W. Schroeder to J. G. Keppler letter dated December 22, 1983 to supplement the report transmitted on October 13, 1987 regarding LaSalle Unit 1 Drywell temperature.
On September 15, 1987, at about 1230 hours0.0142 days <br />0.342 hours <br />0.00203 weeks <br />4.68015e-4 months <br />, temperature sensor ITE-VP211, which measures the metal temperature of a limit switch housing for Main Steam Isolation Valve (MSIV)
"D", indicated above the Environmental Qualification (EQ) setpoint of 150 degrees F.
The temperature stabilized at approximately 168 degrees F, and remained below 180 degrees F during the remainder of the cycle.
Qualified life analyses were performed by Sargent and Lundy for the MSIV equipment affected by the temperature seen by sensor ITE-VP211.
The analyses indicated that sufficient equipment life remained to achieve the next (second) refuel outage.
On September 21, 1987, at 0815 hours0.00943 days <br />0.226 hours <br />0.00135 weeks <br />3.101075e-4 months <br />, it was observed that temperature sensor ITE-VP210, located in the vicinity of the Safety Relief Valves (SRVs),
indicated in excess of the 150 degree F ambient air temperature limit of Technical Specification 3.7.7.a.
The observed temperature of 152.9 degrees F was below the EQ setpoint of 170 degrees F, therefore no change to the qualified life had occurred for the equipment associated with the SRVs.
The temperature remained below the qualification temperature throughout the remainder of the cycle.
Final resolution of this problem is pending completion of the drywell cooling modification (scheduled for third refueling outage).
The cause of the temperature seen by sensor ITE-VP211 could not be determined.
The Unic 1 drywell walkdown, performed at the conclusion of Cycle 2 operation, revealed no packing leak in the vicinity of the sensor.
During the second refuel outage, a functional test to demonstrate the operability of sensor ITE-VP211 was successfully performed.
In addition, the limit switches for the inboard MSIVs were replaced.
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s To. ensure-adequate drywell temperatures during Unit 1 Cycle 3 operation, an insulat, ion walkdown was performed prior to drywell closcout and work was performed to correct as many insulation discrepancies as possible.
Discrepant
-conditions which could not be rectified were evaluated ~and found to have no significant impact on the drywell environmental qualification.
For discrepant ccnditions with the greatest impact on the drywell environment, replacement sections of insulation are being manufactured for installation during outages of sufficient duration during the cycle, after appropriate replacement parts are available.
To ensure accurato drywell temperature data during Unit 1 Cycle 3 operation, the temporary temperature sensors were inspected, repaired as necessary, and functionally tested.
Yo g( G. J. Diederich Station Manager LaSalle County Station
'GJD/MHR/cth cc: Nuclear Licensing Administrator NRC Resident Inspector INp0 - Records Center US NRC Document Control Desk J