ML20086D886

Updated AO 73-02:on 730115,fan 1 on West Cooling Tower Failed in Forward Direction After Completion of Deicing Cycle.Caused by Bearing Failure in Reduction Gear Unit.Fan Disassembled & Angle Speed Reducer Drive Replaced

ML20086D886
Person / Time
Site:	Vermont Yankee
Issue date:	01/22/1973
From:	Rosalyn Jones VERMONT YANKEE NUCLEAR POWER CORP.
To:	US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086D889	List: ML20086D886 ML20086D892
References
AO-73-02, AO-73-2, VYV-2422, NUDOCS 8312050316
Download: ML20086D886 (2)

Text

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VERhi NT YANKEE NUCLEAR POWER CORPORATION SEVENTY SEVEN OROVC STREET RUTI,AND, VERMONT 03701 REPLY TOs VYV-2422 P. o. sox 157 j VERNON VERMONT 05354 January 22, 1973 N

h .jff'h Director ,M 4/.

',7s D\q Directorate of Licensing , j U.S. Atomic Energy Commission Washington, D.C. 20545 [- g

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REFERENCE:

Operating License DPR-28 5 El A 91973nLd

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Docket No. 50-271 hlpg3*G4,, .,, Q Abnormal Occurrence No. A0-73-02 1 Mail :$$ N

Dear Sir:

y An defined by Technical Specifications for the Vernont Yankee w,,r i n n e on,.,ov cc.einn, coreinn 6 7 na uo avo ro nne c < m, cho f n1 1 ni.,4 m, Abnormal Occurrence as AO-73-02.

At 0415 on January 15, 1973, the No. 1 fan on the west cooling tower failed in the forward direction after completion of the deicing cycle.

This particular fan and associated cooling tower cell are necessary to the cooling tower portion of the Alternate Cooling System and must be operable whenever irradiated fuel is in the reactor vessel and reactor coolant temperature is greater than 212*F as required by section 3.5.D.1 of Technical Specifications. The reactor was operating at approxinately 100% power at the time of the incident.

i After the failure, the diesels and the service water sub-systems were checked for operability in compliance with Technical Specifications section 4.5.D.3, and found to be satisfactory. This operability demonstration was g 39 repeated the following day although the fan was returned to service late ,

that af ternoon.

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'G4 Investigation of the fan unit revealed that there was a bearing failure g) in the reduction gear unit. The fan was disassembled, the complete angle g speed reducer drive was replaced, the f an reassembled, tested satisfactorily and restored to service. '

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8312050316 730122 ~ F ,#

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• VERMONT YANKEE NUCLCAR PCWER CORPORATION Directorate of Licensing January 22, 1973 Page 2 The Plant Operations Review Committee concluded that this failure was an isolated instance since twenty-one identical assenblics were in service without similar dif ficulty. After repair and retesting of the angle speed reducer drive, no further action is deemed necessary.

Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION

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Robert F. Jgp s Plant Superfntendent DUE/rpb m..