ML19317D995
| ML19317D995 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 05/13/1976 |
| From: | DUKE POWER CO. |
| To: | |
| Shared Package | |
| ML19317D990 | List: |
| References | |
| RO-269-76-06, RO-269-76-6, NUDOCS 7912100668 | |
| Download: ML19317D995 (1) | |
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DUKE POWER COMPANY t
OCONEE UNIT 1 Report No.:
R0-269/76-6 Report Date: May 13, 1976 Occurrence Date: April 14, 1976 Facility: Oconee Unit 1, Seneca, South Carolina Identification of Occurrence: Failure of Reactor Building Engineered Safeguards isolation valve.
Conditions Prior to Occurrence: Unit at 86% full power.
Description of Oc'urrence:
On April 14, 1976, during the performance of routine surveillance testing, ES valve PR-7 failed in the closed position after being cycled from open to closed. This valve is located in the air sample line for the Reactor Building Purge System and provides containment isolation upon an ES actuation. A work request was issued to investigate the problem, and within two hours the valve was opened for test. However, attempts to reclose the valve were unsuccessful.
Valve PR-7 was then isolated by locking closed the redundant valve PR-8 located outside of the Reactor Building.
This action was completed within 3.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> from the time valve PR-7 was re-opened electrically from the failed closed position.
Technical Specification 3.6.4.b.2 specifies that a containment isolation valve may be inoperable provided that the affected penetration is isolated within four hours by the use of a deactivated automatic valve secured and locked in the isolated position.
Apparent Cause of Occurrence:
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Investigation revealed that the limit switch and torque switch for valve PR-7 were inoperable and that the valve spindle was broken.
Analysis of Occurrence:
Valve PR-7 was properly isolated in compliance with Oconee Technical Specification 3.6.4.b.2 by securing the redundant valve PR-8 in the closed position.
In the event that containment integrity had been required, redundant isolation valve PR-8 on the outside of containment would have closed upon an ES actuation. Containment integrity was not affected by this incident, and it is, therefore, concluded that the health and safety of the public were not affected.
Corrective Action:
i Valve PR-7 has been repaired and its operability verified.
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