ML19319B734

RO NP-33-77-26:on 770724,decay Heat Pump 1-1 Suction Valve Found Closed.Caused by Personnel Neglecting Positive Verification of Valve Position.Operator Reminded of Proper Valve Lineup Procedure

ML19319B734
Person / Time
Site:	Davis Besse
Issue date:	08/17/1977
From:	Batch S, Lingenfelter J TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19319B596	List: ML19319B595 ML19319B734
References
NUDOCS 8001270190
Download: ML19319B734 (2)

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TOLEDO EDISON CCMPANY DAVIS-BESSE UNIT ONE NUCLEAR POWER STATION i SUPPLEMENTAL INFORMATION FOR LER NP-33-77-26 DATE OF EVENT: July 24, 1977 i

FACILITY: Davis-Besse Unit 1 i

l IDENT!?? CATION OF OCCURRENCE: Decay Heat Pump 1-1 suction valve closed.

j Conditions Prior to Occurrence: The plant was in Mode 3, with Power (MWT) = 0

, and Load (MWE) = 0.

t Description of Occurrence: At 2350 hours0.0272 days <br />0.653 hours <br />0.00389 weeks <br />8.94175e-4 months <br /> on July 24, 1977, the plant entered Mode 3. In Mode 3, Technical Specification (TS) 3.5.2 requires both Decay Heat (DH) Pumps to be operable and lined up to be able to provide Low Pressure In-l jection (LPI) to the Reactor Coolant System (RCS) if a Loss of Coolant Accident (LOCA) did occur. At 1515 hours0.0175 days <br />0.421 hours <br />0.0025 weeks <br />5.764575e-4 months <br /> on July 25, 1977, DH Pump 1-1 suction valve l from the Borated Water Storage Tank (BWST), DH 2733, was discovered closed.

I This pl:ced the station into the Action Statement of TS 3.5.2. The Control Room i switch had no indication of valve position even though the breaker for this motor f

t operated valve was closed.

The Control Room Operator was unsuccessful in his attempts to open the valve i from the Control Room switch. The valve was manually opened off the seat, and then at 1615 hours0.0187 days <br />0.449 hours <br />0.00267 weeks <br />6.145075e-4 months <br /> on July 25, 1977, the valve was opened using the motor opera-1 tor. This removed the station from the Action Statement of Technical Specifica-

tion 3.5.2.

l Designation of Apparent cause of Occurrence: The DH suction valve was not open, upon entering Mode 3. Hot Standby, due to personnel error. Open indication on the ,

Control Room switch was not received, nor was local observation of open valve j

! position verified. The cause for the motor operated valve not opening is not l known. The valve was inspected and tested on August 16, 1977, and proper operation i was verified.

Analysis of Occurrence: Since DH Pump 1-2 was available to provide Low Pressure

Injection if needed under accident conditions, no threat occurred to the health l and safety of the public or station personnel. 1 Corrective Action

The operator who neglected positive verification of valve l position cas reminded of its necessity when performing valve lineups. The DH

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suction valve is opened prior to Mode 3 during normal operation and remains open during safety operation. Future improper operation should be discovered on these plant start'ps prior to Mode 3 for which both decay heat pumps are required.

s Failure Data: No previous similar eventa have occurred.

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