ML20084U710

AO 50-265/75-3:on 750104,during Leak Rate Testing of Drywell Personnel Air Lock Penetration,Excessive Leakage Rate Occurred.Caused by Worn Packing on Exterior Door Hand Wheel. Packing Replaced

ML20084U710
Person / Time
Site:	Quad Cities
Issue date:	02/19/1975
From:	COMMONWEALTH EDISON CO.
To:	US ATOMIC ENERGY COMMISSION (AEC)
References
AO-50-265-75-3, NUDOCS 8306290193
Download: ML20084U710 (2)

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I 'sREPORT fiUMBER: A0 50-265/75-[s

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REPORT DATE: February 19,1975 , -

n. . s OCCURREllCE DATE: January 4, 1975 /

FAC li.l TY : Quad-Cities Eclear Powo/ Station Cordova, t 11inois 61242/ .

10ENTIFICAT10NOFOCCUP.PhilCE: ~._

Equipment Failure - Excessive leakage o'n the drywell personnel air lock door seals.

CONDITION PRIOR TO OCCURRENCE: '

.i Unit 2 was in the cold shutdown condition for refueling. The personnel air lock doors were closed and the interior door hold-down bars were installed.

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DESCRIPTION 0F OCCURRENCE:

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, e , 1 Duiing local leak rate testing of the Unit-i drywell personnel air lock penetration l on January 4, 1975, an excessive lealiage rate was experienced when the air lock wcs pressurized to 10 psig.

Tlie. leak rate test was perforc'ed by pressur.Izing tIie volume enclosed by the single-ciasketed seal drvwell norsonnel air 1nck dones. A.lenkona rata of ~41 SCFH, maamerart at a test pressure of 10 psig, exceeded the limit of 18.36 SCFH specified by Tech-nical Specification 4.7.A.2.1.2.b.-

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Subsequent investigation using a soapy, solution with the air lock under pressure showed no visible leaks on any welds or on the interior and exterior door scaling surfaces; however, Icakage was discovered with the, soap bubble solution to be occurring through the packing on the exterior door hand wheel.

A, work request was initiated to repack the# exterior door hand wheel.

DESIGNATION OF APPARENT CAUSE OF OCCURRENCE:

The air lock excessive air leakage is attributed to worn packing on the exterior '

,. door. hand wheel.

ANALYSIS OF OCCURRENCE:

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Although this test was conducthd at 10 psig, the likelihood of an actual occurrence of this pressure inside of the air lock wouut he. minimal due to the redundant

' internal door. Therefore,,in the event of ITccident conditions In'the drywell, the air lock' doors would have' performed their desihn functlon.

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8306290193 750219 / Tr

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A0 50-265/75-3 February 19, 1975

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CORRECTIVE ACTION:

The worn packing was replaced and on January 7,1975, the Unit 2 drywell personnel air lock was retested at a leak rate test pressure of 10 psig. The resultant Icakage was found to be 0.0 SCFH which is within the Technical Specification re-quirements.

FAILURE DATA:

This is the first personnel air lock Icakage failure due to worn packing observed at Quad-Cities Station.

Excessive leakage was experienced on the Unit I drywell personnel air lock in ,

May 1974. This was attributed to deteriorated telephone line conduit sealing material.

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