ML19338D006
| ML19338D006 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 04/30/1970 |
| From: | Hoyt H COMMONWEALTH EDISON CO. |
| To: | |
| References | |
| NUDOCS 8009150598 | |
| Download: ML19338D006 (1) | |
Text
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Commonwealth Edison Company ONE FI R S T NATIONAL PLAZA e C H I C A G O.
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_re Dr. Peter A. Morris, Director C t-4. -.
Division of Reactor Licensing
-7 U.
S.
Atomic Energy Commission 1
Washington, D.
C.
20545
Dear Dr. Morris:
The purpose of this letter is to inform you of an unusual operating experience on Dresden Unit 1.
This experience was the failure of a motor perated valve during an operational check of the valve prior reactor startup.
s Unit 1 was shut down for maintenance on April 16, 1970.
On April 23, 1970, the safety system check-off sheets were being completed in preparation for s t ar tu p.
The reactor mode switch was in refuel with all rods inserted.
During the operational check of the emergency condenser, it was found that the MO-101, the north emergency condenser condensate valve, failed to open.
The valve was satisfactorily opened and closed manually -indicating the 125 V DC motor had failed.
The motor was remaved and dis-assembled, and inspection indicated signs of overheating.
This motor is located in the primary steam drum compartment and exposed to above ambient temperatures.
The motor on the south emergency condenser condensate valve, MO-109, was remcved for inspection and found to be in good condition.
MO-101 was repaired and both motors were returned to service on April 25, 1970.
These v alve s were last checked on December 27, 1969 during our normal surveil-lance and found to operate normally.
The station plans to take action to avoid this problem by extending both valve operators outside of the steam drum compartment so that the motors will be in an accessible and cooler location.
This relocation of the motor operators will be done during the 1971 Refueling Outage.
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Sincerely,
,s D0;KETED M
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Superintendent yut'- '
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