ML20085G998

AO BFAO-738W:on 730904,steam Supply Valve FCV-73-16 Failed. Caused by Misalignment of Motor Pinion on Motor Shaft & Three Chipped Gear Teeth.Gears Replaced

ML20085G998
Person / Time
Site:	Browns Ferry
Issue date:	09/12/1973
From:	Eric Thomas TENNESSEE VALLEY AUTHORITY
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085G999	List: ML20085G998 ML20085H004
References
AO-BFAO-738W, NUDOCS 8308300043
Download: ML20085G998 (2)

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TENNESSEE VALLEY TENNESSEE CHATT*ANOOGA, AUTHO AITY C"~J]t f

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panmenssin 1 September 12, 1973 d 7,', . h,h -

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d * *y i Mr. John F. O'Iaary, Director . /

Directorate of Licensing N// O 3" .N ' p Office of Regulation N M. '

U.S. Atomic Energy Ccmmission y@ h '

Washington, DC 20545 QM,[~, . . . . . , -

Dear Mr. O'Icary:

TENNESSEE VALLEY AUTHORITY - BROWNS FERRY NUCIEAR PLANT UNIT 1 -

DOCKET NO. 50-259 - FACILITY OPERATING LICEUSE DPR ABNOEMAL OCCURRENCE REPORT BFAO-738W The purpose of this report is to provide details concerning the -

malfunction of a steam supply valve to the hi Sh-pressure coolant injection (HPCI) turbine at Browns Ferry on September 4,1973 Description of the Incident r--

During routine testing of the HPCI with auxiliary steam at 1 p.m.

on September 4, steam valve FCV-73-16, which ie the eteam supply j

valve to the turbine, failed to operate. Preliminary investigation showed the trouble to be in the valve gearbox. The reactor was in the shutdown condition and had never been operated beyond open vessel testing. -

Investigation and Corrective Action i

Removal of the limitorque drive motor revealed several scored or damaged motor pinica gear teeth. Incpection of the clutch gear, which meshes with the motor pinion, revealed three chipped gear teeth. The damaged teeth showed that the gears had not been properly axially aligned since there was only 3/16- to 1/4-inch engagement of the teeth. The cause of misali nment 8 was the improper positioning of the motor pinion on the motor shaft. {

The shouldered gear had been placed on the shaft backwards

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vith the shoulder towards the motor, thus axially misaligning j the gears.

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8308300043 730912

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kr. John F. O' Leary Septenber 12, 1973 TENNESSEE VALLEY AUTHORITY - BROWNS FERRY NUCLEAR PLANT UNIT 1 -

DOCKET NO. 50-259 - FACILITY OPERATING LICENSE DPR ABNOPMAL OCCURRENCE REPCRT BFAo-738W The corresponding Gears were re=oved from a similar limitorque on unit 2, which is still under construction, and inctalled in the motor operator. The valve was operated electrically to test serviceability. Satisfactory completion of the HPCI surveillance test demonstrated operability of the valve. The HPCI system was returned to service on September 5,1973 Very truly yours, TENNESSES VALLEY AUTHORITY WM E. F. Thomas Director of Power Production -

CC: Mr. Noman C. Moseley, Director Region II Regulatory Cperations Office, USAEC 230 Peachtree Street, NW.

Atlanta, Georgia 30303 f O

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