ML19329A675
| ML19329A675 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 10/14/1976 |
| From: | DUKE POWER CO. |
| To: | |
| Shared Package | |
| ML19329A670 | List: |
| References | |
| NUDOCS 8001090659 | |
| Download: ML19329A675 (1) | |
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OCONEE UNIT 3 Report No.: R0-287/76-17 Report Date: October 14, 1976 Occurrence Date: September 17, 1976 Facility: Oconee Unit 3, Seneca, South Carolina Identification of Occurrence:
Reactor Building Cooling Unit inoperable due to defective motor Conditions P'ior to occurrence: Unit at 33 percent full power r
Description of Occurrence:
On September 17, 1976, it was determined that the 3C Reactor Building cooling unit breaker ~had tripped.
Investigation revealed that the 3C RBCU three phase fan motor had failed. The motor was inoperable for one day of power operation before Oconee Unit 3 was shutdown for refueling.
Apparent Cause of Occurrence:
The probable cause of the occurrence was an insulation failure on one phase of the three phase fan motor, resulting in an insulation breakdown on the other two phases and subsequent grounding of the motor.
Analysis of Occurrence:
For the period of time during which the 3C RBCU was out of service, boch Reactor Building spray systems and the remaining,ao Reactor Building cooling units were operable as required by Oconee achnical Specification 3.3.6.(d).
These systems have full heat removal capability in the event of an ES actuation and, therefore, it is concluded that the health and safety of the public were not affected by this occurrence.
Corrective Action:
The 3C RBCU fan motor was replaced and an analysis of the failure mode of the defective motor is being made. The 3A and 3B RBCU fan motor insulation will be examined using a 500V Megger prior to Oconee Unit 3 startup.
Addi-tionally, the Oconee Unit 1 and 2 RBCU fan motors will be examined during each unit's refueling outage..This incident is considered to be an isolated occurrence and is not indicative of a generic problem.
It is felt that this corrective action will prevent reoccurrence of this incident.
S00 7 $90dQ