ML19256A786

to Suppl Info Sheet for LER NP-33-78-120 on 781005.Other Svc Water Valves Associated W/Component Cooling Water Heat Exchangers Were Inspected for Similar Inoperable Conditions.No Problems Noted

ML19256A786
Person / Time
Site:	Davis Besse
Issue date:	01/02/1979
From:	TOLEDO EDISON CO.
To:
Shared Package
ML19256A784	List: ML19256A783 ML19256A786
References
NUDOCS 7901160154
Download: ML19256A786 (1)

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TOLEDO EDISON COMPANY DAVIS-BESSE UNIT ONE NUCLEAR POWER STATION SUPPLEMENTAL INFORMATION FOR LER NP-33-78-120 DATE OF EVENT: October 5, 1978 FACILITY: Davis-Besse Unit 1 IDENTIFICATI0.: OF OCCURRENCE: Component Cooling Water (CCW) Loop 1 inoperable due to inoperability of heat exchanger outlet valve Conditions Prior to Occurrence: The unit was in Mode 1, with Power (MWT) = 2772, and Load (MWE) = 925.

Description of Occurrence: On October 5,1978 at 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br />, the Control Room operator unsuccessfully attempted to open the CCW Heat Exchanger 1 Service Water Outlet Valve SW 1424 to control CCW heat exchanger 1 outlet temperature. He then attempted to manually stroke or operate SW 1424, but it renained closed. CCW Loop 1 was declared inoperable.

The unit was placed in the Action Statement of Technical Specification 3.7.3.1, which requires the operability of two independent cooling water loops in Modes 1, 2, 3, and 4. The action statement specifies that the inopnrable loop should be restored to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or the unit must be in Hot Standby (Mode 3) within the next six hours, and in Cold Shutdown (Mode 5) within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

Designation of Apparent Cause of Occurrence: Upon visual inspection it was dis-covered that a nut on the actuator linkage for the valve was missing. The valve had failed in the closed position since the positioner was not connected to the actuator.

Analysis of Occurrence: There was no danger to the health and safety of the public or unit personnel. The other CCW loop was operable during the short period that CCW Loop 1 was inoperable.

Corrective Action: CCW Loop 1 temperature was controlled by taking manual control '

of the valve. Instrument and Control technicians replaced the linkage arm bolt and set the stroke on SW-1424 under Maintenance Ucrk Order IC557-78. Under Maintenance Work Order IC558-78, the valve operator was recalibrated, and the position switches set.

Af ter satisfactorily completing stroke times, the valve was declared op trable at 1425 hours0.0165 days <br />0.396 hours <br />0.00236 weeks <br />5.422125e-4 months <br /> on October 5, 1079. The unit tms removed from the Action Statement of Technical Specification 3.7.3.1.

Under Maintenance Work Order IC-606-78, other service water valves associated with 1 , the CCW Heat Exchangers were inspected for similar conditions with no nrohlers noted.

LER #78-101 7901Ieoy3