ML19329A655
| ML19329A655 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 10/07/1976 |
| From: | DUKE POWER CO. |
| To: | |
| Shared Package | |
| ML19329A652 | List: |
| References | |
| RO-287-76-16, NUDOCS 8001090637 | |
| Download: ML19329A655 (1) | |
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DUKE POWER COMPANY OCONEE UNIT 3 Report No.: R0-287/76-16 Report Date: October 7, 1976 Occurrence Date: September 12, 1976 Facility: Oconee Unit 3, Seneca, South Carolina Identification of Occurrence: Loss of power to ES equipment due to failure of static inverter Conditions Prior to Occurrence:
Unit at 45 percent full power Description of Occurrence:
On September 12, 1976 the failure of an input filtering capacitor on the 3DIB Vital Bus Inverter resulted in a loss of power to the 3KVIB AC Vital Instru-mentation Power Panelboard. This resulted in various parameters of the RPS Channel B tripping.
Power was immediately restored by manually transferring the 3KVIB panelboard loads to the 3KRA AC Regulated Power Panelboard.
The 3DIB Vital Bus Inverter was returned to service in approximately 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
Apparent Cause of Occurrence:
The apparent cause of this occurrence was the breakdown of the dielectric of an input filtering capacitor on the 3DIB Vital Bus Inverter.
This mal-function caused a current surge which tripped the inverter input circuit breaker and resulted in the loss of power to the 3KVIB AC Vital Instrumen-tation Power Panelboard.
Analysis of Occurrence:
1 This occurrence resulted in the trip of various parameters associated with RPS Channel B.
Additionally, the even digital channel ES actuation and one ES analog channel actuation were not available for the very short period of time necessary to manually transfer the 3KVIB panelboard to the regulated AC source. During this short time period, the redundant odd digital channels ar.d two remaining ES analog actuation channels were available and would have functioned properly if required.
During the time period that inverter repairs were in progress, these functions received AC power from a non-load-shed AC l
source and would have functioned properly if required.
The 3DIB vital bus inverter was restored to service within the time. period permitted by Technical Specification 3.7.2.(d).
Is is therefore ccrxlatral that due to the availa-bility of redundant ES equipment and the brief interval over which power was lost that the health and safety of the public was not affected by this occur-rence.
Corrective Action:
The 3DIB Vital Bus Inverter was repaired and returned to service.
This occur-rence was a random equipment failure and, therefore, it is felt that no further corrective actien is appropriate.
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