ML19316A381

RO 269/78-08:on 780315,valve FDW-108 Failed to Close.Failure Has Occurred Previously.Caused by Apparent Unsuitability of Valves for long-term Operation in Sys Environ.Valve Stem Lubricated.Valves Will Be Replaced

ML19316A381
Person / Time
Site:	Oconee
Issue date:	04/11/1978
From:	DUKE POWER CO.
To:
Shared Package
ML19316A379	List: ML19316A378 ML19316A381 ML19316A384
References
RO-269-78-08, RO-269-78-8, NUDOCS 7912110642
Download: ML19316A381 (1)

Text

.

DUKE POWER COMPANY OCONEE UNIT 1 Report Number: R0-269/78-8

ort Date

April 11, 1978 cccurrence Date

March 15, 1978 Facility: Oconee Unit 1, Seneca, South Carolina Identification of Occurrence: Valve FDW-108 failed to close Conditions Prior to Occurrence: 100 percent full power Description of Occurrence:

On March 15, 1978, after taking a steam generator sample,.lFDW-108 failed to close under system pressure. Redundant valve 1FDW-107 was locked closed within four hours pursuant to Technical Specification 3.6.3b(2). After stem lubrication the valve was cycled and verified to be operable.

Apparent Cause of Occurrence:

This type of valve failure on this and other identical valves has occurred on several previous occasions. Corrective actions suggested by the manu-facturer have been unsuccessful in resolving the problem. The valves appear to not be suited for long-term operation in the system environment.

Analysis of Occurrence:

1FDW-108 is an isolation valve on the steam generator sample line. The failure of the valve did not violate containment integrity as the redundant valve was operable and would have performed its Engineered Safeguard func-tion if necessary. Thus, the health and safety of the public were not endangered.

Corrective Action:

The valve stem was lubricated and cycled to assure operability.

This failure is one of several similar failures which have been occurring at the Oconee Nuclear Station. The affected valves (FDW-106 and -108) will be replaced by ones of a different design at the first appropriate outage for each unit after September 1, 1978.

7912110[d g,

.