ML20085G727

AO BFAO-7313W:on 730914,differential Pressure Switch PdIS-71-1A of Isolation Logic Exceeded Tech Spec Setting. Switch Recalibr & Monthly Testing Increased to Once Every 2 Wks

ML20085G727
Person / Time
Site:	Browns Ferry
Issue date:	09/24/1973
From:	Eric Thomas TENNESSEE VALLEY AUTHORITY
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085G728	List: ML20085G727 ML20085G738
References
BFAO-7313W, NUDOCS 8308290303
Download: ML20085G727 (2)

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TENNESSEE CHATTANOOGA, VALLEYTENNESSEE AUTHOAITY MTT . f

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(,k. 3t[b5 September 24, 1973 _n ff

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PART NI_ FMiHIP t'

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Mr. John !. O' leary, Director Directorate of Li 2nning 1,j q

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V Office of Regulation U.S. Atomic Energy Comnission A" '/

Washington, DC 205h5

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Dear Mr. O' leary:

TE!CIESSEE VALLEY AUTHORITY - EROWIIS FERRY I;UCI2AR PIluT U?IIT 1 -

i DOCTET Iio. 50-259 - FACILITY OPSRATING LICEI!SE DPR AE iORMAL OCCURRE !CE RSPORT BFAO 'l313W The purpose of this report in to provide details concerning the s i

i malfunction of a differential pressure switch in unit 1 RCIC isolation logic at Browns Ferry I;uclear Plant on September 14, 1973 u This occurrence was reported by telegram on September 14, 1973, to the Region II Directorate of Regulatory Operations, Atlanta, Georgia.

e Dercription of the Incident During routine curveillance c

testing on September 14, 1973, PdIS-71-1A vas found to operate outside the technical specification setting of  :

equal to or less than 450 inches of water as specified in table 3 2.B.

The as-found setting vac 457 inches of water. i The cwitch han two contacts in parallel that fom a trip logic in  :

i the trip system. The trip logic ccts to trip the RCIC turbine and  !

isolate the system upon stera line high flow. Since only 1 of the  ;

2 channels is required operable and tne other channel tested i

satisfactorily, the logic vould have perfomed its intended function L if required. The reactor was in the COLD, SRUTDOWN condition; and RCIC was not required.

g This is a Earton differeatial indicatin6 switch, Model 288, with a range of 0-to-500 inches of vater. It was last runctionally tested [

i on nagust 1*(,1973, and was found satisfactory. The switch was e inspected for catisfcetory clearance and freedom of operation and  !

was recalibrated allowing for instrument accuracy. Several operations -

of the switch were perfomed to ensure operability.

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Mr. John F. 0 % ary September 2!+,1973 TENNESSEE V/.LLEY AUTl!ORITY - EROWNS FERRY HUCLEAR PIET UNIT 1 -

DOCKET NO. 50-259 - FACILITY OPERATIIC LICENSE DPR ABNORMAL OCCURRENCE RSPORT EFAo-7313W Thic instrument will be scheduled for testing once every two weeks until three concecutive tests prove caticfactory performance. At that. time, the original test schedule of once a month will be recumed.

Very truly yours, TENNESSEE VALIEY AUTEORITY Y LL~ L' x E. F. Thcmas

' Director of Power Production CC: Mr. Norman C. Moseley, Director e Regicn II Regulatory Operations Office, USAEC 230 Peachtree Street, IF..'

Atlanta, Geor81 a 30303 c

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