ML17266A087

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LER 79-022/03L-0 on 790627:during Periodic Surveillance, Testing Auxiliary Feedwater Pump Failed to Start.Cause Could Not Be Determined.Condensation in Steam Line May Have Delayed Starting Enough to Mislead Operator
ML17266A087
Person / Time
Site: Saint Lucie NextEra Energy icon.png
Issue date: 07/27/1979
From: Schoppman M
FLORIDA POWER & LIGHT CO.
To:
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML17206A944 List:
References
LER-79-022-03L, LER-79-22-3L, NUDOCS 7908070505
Download: ML17266A087 (3)


Text

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"B" steam supply could not be determined at the time of the occurrence.

Later pump operation indicates that condensation in the steam sutt, v ACTIVITY line ma have delaved the start sufficientl to lead the 1

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Reportable Occurrence 335-79-22 Licensee Event Report Page t>>o Additional Cause Descri tion and Corrective Action During periodic surveillance testing the 1C auxiliary feedwater pump failed to start from the "B" steam supply. The pump was started successfully from the "A" steam supply and then started success-fully from the "B" steam supply. No cause for the failure to start on the first attempt could be determined at the time of occurrence. Later pump operation indicates that the pump may not actuallj have failed to start.

On 7-16-79 during operator training exercises the 1C auxiliary feedwater pump was started locally from the "B" steam supply header. An excessive quantity of water was observed issuing from the turbine exhaust, and the pump came up to speed at a much slower rate than normal. Further investi-gation'evealed that a recent change to operating procedure 0700022 changed normally open warm-up valves V8384 and V8385 to normally closed to agree with the system P and 1D. 'Closing these, valves created a trap for conden-sation build-up upstream of the "B" steam supply valve MV08-13.

It is now hypothesized that the build-up of condensation created a water turbine effect in the first seconds of the attempted pump start which resulted in a much slower rate of acceleration.

Normally, the pump reaches appcoximately 2000 rpm in 15-20 seconds and when the operator did not see any indication of rpm in that time frame, he manually tripped the pump. It is felt that the pu-..p was slowly accelerating as the water was passing through the turbine and the pump would have started had it not been tripped manually.

Corrective action is to maintain the valves in a normally open configuration under OP 0010122.

Review by the Facility Review Group has determined that maintaining the valves open does not jeopardize plant safety. Engineering will be requested to verify the FRG's findings.