ML19270F683

LER 79-003/03L-0 on 790118:flange Seal Gasket Was Leaking in Excess of 30 Std Cubic Feet Per Second.Caused by Seal Gasket Wear.Seal Gasket Will Be Inspected Further & Replaced If Necessary

ML19270F683
Person / Time
Site:	Quad Cities
Issue date:	02/16/1979
From:	Tietz G COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML17296A304	List: ML17296A303 ML19270F656 ML19270F659 ML19270F662 ML19270F668 ML19270F673 ML19270F676 ML19270F679 ML19270F682 ML19270F683 ML19270F684
References
LER-79-003-03L-08, LER-79-3-3L-8, NUDOCS 7903070373
Download: ML19270F683 (2)

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EVENT CE52ni3T'.1 I. '.; A C &_E CC '. 3 2CU EN CEI f)

While performing the Dr well Head Flange local leak rate test, it was determined the i

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34 30 31 40 41 43 CAUSE DESCRIPTION AfiD CORRECTIVE ACTIONS h The probable cause of the excessive leakage is due to seal gasket wear. The seal l li o l li li g l gasket will be further inspected and replaced i f necessary. A second leak rate test l

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1111lilillilII LO 5 NAME OF PHEPAnER _ Q. Tiet7 PHONE: 309-654-2241 ext. 247 ('

1. i.ER NUMBER: LER/R0 79-03/03L-0 ll. LjCENSEE NAME: Commonwealth Edison Company Quad-Ci ties Nuclear Power Sta tion Ill. FACILITY NAME: Unit Two IV. DOCKET NUMBER: 050-254 V. EVENT bESCRIPTION:

On January 18, 1979, while performing a local leak rate test on the Drywell Head Flange, it was determined the flange seal gasket was leaking in excess of 30 SCFH. The flange was tested in accordance with procedure QTS 100-2. This leak rate was probably greater than the allowable limit for all double gasketed seals of 36.72 SCFH, per Technical Specification 4.7.A.2.1.1.

VI. PROBABLE CONSEQUENCES OF THE OCCURRENCE:

The safety implications of this occurrence are minimal due to the fact the amount of leakage measured was small. Also, it is possible that not all the leakage would have es aped past both double knife edge seals. Since drywell pressure i, closely monitored, had a gross leak occurred it would have been noticed and a safe and orderly shutdown commenced.

Vll. CAUSE:

The probable cause of the excessive leak rate is due to seal gasket wear. Upon inspection of the gasket, numerous perfora-tions and tears were found to exist. Although the gasket was still pliable, repeated placements of the drywell head during past outages caused indentations in the gasket which created leakage paths.

Vill. CORRECTIVE ACTION:

The immediate correction was to write work request number 323-79 to repair or replace the fle.'qe seal gasket. After repairs are made, the flange will be loceI leak rate tested again. A supple-ment will be submitted which will include the repairs that were made and the results of a follow up leak rate test, which will be performed prior to unit start-up.