ML19317F175
| ML19317F175 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 08/25/1975 |
| From: | DUKE POWER CO. |
| To: | |
| Shared Package | |
| ML19317F174 | List: |
| References | |
| RO-287-75-09, RO-287-75-9, NUDOCS 8001080892 | |
| Download: ML19317F175 (2) | |
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DUKE POWER COMPAhT OCONEE UNIT 3 Report No.: UE-287/75-9 Report Date: August 25, 1975 Event Date: July 14, 1975 Facility 1 Cconee Unit 3, Seneca, South Carolina Identification of Event: Failure of personnel hatch interlocks Conditions Prior to Event: Unit at full power Description of Event:
On July 14, 1975,, rsonnel entering i:he Reactor Building checked the personnel batch interlocks and found the inner door interlock was not functioning pru;;::1y. Administrative controls were taken to assure that both doors were not opened simultaneously.
Designation of Apparent Cause of Event:
Each door of the perscnnel hatch has a gear which is rotated by the door handwheel. A pawl mechanism, in conjunction with this gear, creates a ratchet mechanism to prevent rotation of the door handwheel should the opposite door be open. The pawls are raised from or lowered on the gear by motion of the opposite door transmitted through a cable and linkage mechanism. The apparent cause of this event was insufficient spring tension on the interlock cable.
Analysis of Event:
1 Prompt action was taken to prevent simultaneous opening of both hatch doors.
The interlock mechanism was repaired and operable within approxi-l mately one hour of discovery of its failure. Containment integrity was maintained at all times.
It is-concluded that the health and safety of the public was not affected.
Corrective Action:
The spring tension on the interlock cable was adjusted and the personnel hatch was returned to service. The interlocks were tested approximately ten times to verify operability.
Additional action has been taken to preclude further failures of the interlock mechanism including:
(1) A preventive maintenance program for the personnel and emergency hatches has been implemented.
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(2) Several modifications have been implemented to improve the operability and reliability of the interlock mechanisms.
1080
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i Failure Data:
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-Previous failures of the personnel hatch inte-!ocks on Oconee Unit 3 were reported as UE-287/75-3 and UE-287/75-8.
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