ML19347D958

LER 81-031/03L-0:on 810315,auxiliary Feedwater Pump 1A-A Declared Inoperable When Observed to Have Abnormal Vibration & Odor.Vibration Caused by Deterioration of Inboard Bearing Insulation Which Allowed Excessive Shaft Movement

ML19347D958
Person / Time
Site:	Sequoyah
Issue date:	04/08/1981
From:	TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19347D953	List: ML19347D952 ML19347D958
References
LER-81-031-03L-03, LER-81-31-3L-3, NUDOCS 8104140525
Download: ML19347D958 (2)

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[ o s a l ] was declared inonerable when it was observed ,to have a' h normal vibration and odor f I: laj l resulted in enterind the action statement of limitine condition 'for onerheion 3.7.1.2. 1 h j3) [ The motor. driven auEiliary feedwater puer) IB-B p'rovided the'feedwater requirements. There r

[ o is ; l were no prev'ious occurrences. There was no danger to the health arid safety of the public.

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i,,;j l guards due to' friction. This overheating caused the motor to smell like biirnt oil. The

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, Sequoyah Nuclear Plant LER SUPPLEMENTAL INFORMATION SQRO-50-327/81031 Technical Specification Involved:

3.7.1.2 Reported Under Technical Specification: 6.9.1.13.b Time of Occurrence: 0300 CST

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Date of Occurrence: 3/15/81 Identification and Description of Occurrence: .

lA-A auxiliary feedwater pump was declared inoperable due to excessive vibration and a smell of burnt oil from outer bearing.

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Conditions Prior to Occurrence: .

Unit 1 in Mode 3, hot standby i Apparent Cause of Occurrence:

A failure of the motor bearing insulation Analysis of Occurrence The inboard bearing insulation was found to be deteriorated, thus allowing the bearing enough mobility to vibrate within the motor endbell housing.

The bearing failure also allowed the motor shaft to contact the inner and outer oil guards on the inboard end and the inner oil guard on the outboard end.

Corrective Action:

The motor was disassembled, bearings replaced, oil guards reworked, and the motor' reassembled in accordance with the manufacturer's instruction book.

The motor was functionally tested by surveillance instruction SI-130.2 after repairs.

Failure Data:

There have been no other failures of these bearings.

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