ML19317D842
| ML19317D842 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 10/21/1974 |
| From: | DUKE POWER CO. |
| To: | |
| Shared Package | |
| ML19317D832 | List: |
| References | |
| RO-269-74-06, RO-269-74-6, NUDOCS 7912100571 | |
| Download: ML19317D842 (1) | |
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DUKE POWER COMPAh7 OCONEE UNIT 1 4
Report No.: UE-269/74-6 Report Date: October 21, 1974 Event Date:
September 9, 1974 Facility: Oconee Unit 1, Seneca, South Carolina Identification of Event:
Trip breaker cabinet seismic deficiency Conditions Prior to Event:
Various power levels to 100 percent full power Description of Event:
A re-evaluation of the seismic qualification of the control rod drive system AC breaker cabinets has been performed for the Oconee Nuclear Station by the Babcock & Wilcox Company.
This analysis has revealed that the attachment of the cabinet to the floor is possibly inadequate to withstand the safe shutdown earthquake (SSE) acceleration levels.
Analysis of Event:
The Control Rod Drives (CRD) are tripped by a loss of power to the drive stators.
Power is interrupted by disengaging either the AC or DC control rod drive breakers.
In the unlikely event of a seismic disturbance, analysis cannot verify the integrity of the AC breaker cabinet floor mountings.
The subsequent random motions of the cabinet have not been analyzed to ensure that the AC breakers would always perform as designed.
The DC breakers would function to interrtpt powar to the control rod drives and ensure that the reactor would be shut down.
It is concluded that the health and safety of the public will not be endangered during the time necessary to rectify this situation.
Correctivo. Action:
A modification is being prepared which will increase the attachment strength of the cabinet to the floor either through additional bolting or using a fillet veld.
This codification will Se completed by February 1, 1975.
7912100 S'7/
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