ML19256A693

LER 78-101/03L-0,supplemental Info Sheet:On 781005,Component Cooling Water Loop 1 Inoperable Due to Inoperability of Heat Exchanger Outlet Valve.Caused by Missing Nut on Actuator Linkage for Valve.Replaced Linkage Arm Bolt & Set Stroke

ML19256A693
Person / Time
Site:	Davis Besse
Issue date:	01/02/1979
From:	TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19256A689	List: ML19256A687 ML19256A693
References
LER-78-101-03L-01, LER-78-101-3L-1, NUDOCS 7901090210
Download: ML19256A693 (1)

Text

,

0 TOLEDO EDISON COMPA'IY 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 IDENTIFICATION 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 (FRCE) = 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 remained 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 inoperable 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-overed 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 uncer Maintenance Work Order IC557-78. Under Maintenance Work Order 1C558-78, the valve operator was recalibrated, and the position switches set.

After satisfactorily completing stroke times, the valve was declared operable 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 uns removed fron the 4.ction 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 nrohlems noted.

7 9 010 9 0 A/('