ML17338A693

LER 79-006/03L-0 on 790322:packing leak-off Observed on Three Valves.Cause Undetermined for Two Valves.Leaking Packing on Third Due to Broken Bellows Seal.Unit in Reeling Shutdown;Repairs Will Be Made Before Return to Power

ML17338A693
Person / Time
Site:	Turkey Point
Issue date:	04/20/1979
From:	Schoppman M FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML17338A692	List: ML17338A691 ML17338A693
References
LER-79-006-03L-02, LER-79-6-3L-2, NUDOCS 7905080571
Download: ML17338A693 (4)

Text

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Cg REPORTABLE OCCURRENCE 251-79-6, 0

LICENSEE EVENT REPORT P AGE TWO Additional Event Descri tion and Probable Conse uences The Plant Nucleary Safety Committee (PNSC) 'reviewed the evaluation of the Unit 4 Reactor Coolant System leakage rate that was in excess of 1 gpm. The sequence of events and the evaluation follows:

At about 7:00 AH on Tuesday, March 20, 1979, the routine calculation of RCS leak rate indicated a leak rate of 1.27 gpm.-. An investigation was initiated to determine the source of this, excess leakage.

By 3:00 PH, March 20, 1979, excess leakage was from:

it was tentatively determined that the source of the (1) Xhe 4A Reactor Coolant Pump number' seal leak-off as there were periodic, standpipe "high. level" alarms, (2) 'valve packing leak-off to the Reactor Coolant Drain Tank (RCDT) as ~

observed by periodically needing to quench the Reactor Coolant Drain Tank to maintain temperature below 180'F,.and (3) the 4A and 4B charging pump seal pots overflowing.

The leak rate remained stable at approximately 1.60 gpm through 7iednesday, March 21,'1979.

By about 7:00 AH on Thursday,.Harch 22, 1979, the leak rate had increased to 1.85 gpm and by 12:30 PH had increased to 2.85 gpm. At about 1 35 PH, the decision was made to place the reactor in hot shutdown in order to make entry inside the containment biological shield to determine the source of the increased leak rate.

The reactor was in hot shutdown at about 2:40 PH.

At 4:45 PH, a containment entry was made. The source of the leaks was found to be valve packing leak-offs to the RCDT from pressurizer valves HOV-4-535, HOV-4-536 and PCV-4-455A. In addition,. a minor leak was found from a swagelok fitting at the incore detector seal table for one of the score detector thimbXes that was draining to the containment sump.'ll leaks were evaluated as minor.

At about 8:30 AH on Friday, Harch 23, 1979, a second containment entry was made to ensure that all leakage areas had been identified and that the leakage at the incore detector seal table had not increased. No additional leaks were found and the leak rate at the incore detector seal table had not increased above the orig-inal leak rate observed.

Unit 4 was returned to service at about 2:40 PH on Friday, March 23, 1979.

The PNSC agreed with the evaluation that the leakage rate was minor.and recommended

the leak rate be checked once per each 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> shift in order to monitor trends in the water inventory. The PNSC determined operation of Unit 4 with this leakage would not involve any unreviewed safety questions.

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