ML20084H470

AO BFAO-50-260/741W:on 740730,11 of 14 Seismic Restraints Supporting Yarway Water Columns on Reactor Pressure Vessel Found Inoperable.Caused by Failure to Lubricate Restraints During Factory Assembly.New Restraints Installed

ML20084H470
Person / Time
Site:	Browns Ferry
Issue date:	08/09/1974
From:	Eric Thomas TENNESSEE VALLEY AUTHORITY
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084H462	List: ML20084H464 ML20084H470 ML20084H472 ML20084H474
References
NUDOCS 8305040299
Download: ML20084H470 (2)

Text

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TENNESSEE \/A1_LE: AUTHC AITY I'~3". 7 T's

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ANN'ihFN 53 NY August 9, 1974 ,s-,- cf!\u d, Q- f *f;. gg;gjgjg

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Mr. John F. O' Leary, Director i

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Directorate of Licensing Office of Regulation

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Dear Mr. O' Leary:

THETESSEE VALLEY AUTHORI5f - BROWS FERRY IIUCLEAR PLANT UNIT 2 -

DOCKET 1:0, 50-260 - FACILITf OPERATING LICEIISE DPR AEliORMAL OCCURRE;CEREPORTBFAO-50-260/741U ,

1 The enclosed report is to provide details concerning 11 of 14 scisnic restraints used to support the Yarway weter colur:ns on the reactor pressure vessel which vere found in an inoperativo condition on July 30,1974, and is submitted in accordance with Appendix A to Regulatory Guide 1.16, Revision 1, October 1973.

Very laula yvalo, TENNESSEE VALLEY AUTHORITI

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E. F. Thomas Director of Power Production Enclosure CC (Enclosure):

Mr. !'ornan C. Roseley, Director Region II Rc5ulatory Operations Office, USAEC 230 Pcachtrec Street, liW. , Suito Bib Atlanta, Georgia 30303 ,

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-..l hEHORMAL OCCURPJ2TCZ PIPORT l Report No.: BFAO-50-260/741W Report Date: August 9, 1974 -

Occurrence Date: July 30, 1974 Facility: Browns Ferr/ Nuclear Plant unit 2 Identification of Occurrence On July 30,1974,11 of 14 cei =ic restraints used to support the Yarway water colu=ns on the reactor prescure vessel were found in an inoperative condition.

Conditions Prior to Occurrence i

The reactor was shut down and preparations were under way for initial nucicar heatup.

Descrintion of Occurrence While correcting an interference problem that was discovered during the perfc=nnte of startup test, STI-17, a seismic restraint on one of the RFV Yarway colu=c was noticed to be extended too far. When this seienic restraint was taken 1cose for correction, it was found to be seized. A check was then cade of the new Yer.,my column ceicnic rectraints in the varchouse and it vac found that 5 out of 14 :ere either =ci::d er V ld not retr a t eftcz bcii.g u Le led. All of the se:Isi le restraint: in unit 2 were then checked end it was found that 11 cut of 14 vero h operative. -

Decicnation of Annarent Cause of Occurrence l

An inspection of both the old and new seismic restraints for the Yarway column revealed that the restraints were not lubricated during ascc bly at the facte:y.

Analysic of Occurrence The fact that these restraints were seiecd presented no cafety problem. With the Yarway colu=n coismic restraints seized, the Yart.my colu n could have with :ced a minirma of 300 cycles from hot to cold or cold to hot without failure.

Corrective Action Fourteen new seismic restraints were obtained from the factory and installed in unit 2. Oft documentation was received frca the tanufacturer on each of thece newly accenbled restraints certifying that they were instected at each asseroly step. The new seirnic restraints were functionc?ly checked upon receipt end following installation at Brown Ferrf.

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Bethel, Connecticut .

MSVA - Pechanical Shock and Vibration Arrester - 1A TT-4 AT-1.5

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