ML20085H009

AO BFAO-737W:on 730902,core Spray Sys Loop I Failed to Deliver Required Flow at Required Sys Pressure.Caused by Instrument Error.Flow Transmitter Recalibr & Calibr Frequency Changed to Bimonthly

ML20085H009
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
ML20085H013	List: ML20085H009 ML20085H016
References
BFAO-737W, NUDOCS 8308300066
Download: ML20085H009 (2)

Text

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TENNESSEE VALLEY AUTHO Al rY F2n M CHATTANCOGA, TENNESSEE i'T/j (J . , #

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3 A N rdih C b S h Y g, e %TA9:h%'s September 12, 1973 7 , h/[kk 9

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r, Mr. John F. O'Ioary, Director

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9 ., ,Jg8L. y Directorate of Licensing W Office of Regulation U.S. Atomic Energy Commissien \ s

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Washington, DC 205!+5 .,,' .; M Q'b'

Dear Mr. O' leary:

l l TENNESSEE VALLEY AUTHORITY - BROWNS FERRY NUCLEAR PIKIT UNIT 1 -

DOCKET NO. 50-259 - FACILITY OPERATING LICEIISE DPR AENORMAL OCCURRENCE RSPORT EFAo-737W The purpose of this report is to provide details concerning the suspected failure of the core spray system (CSS)-kop I to deliver required flow at required system pressure. This occurrence was reported on September 3, 1973, by telephone and telegram to the AEC Region II Directorate of Regulatory Operations in Atlanta, Georgia.

Description of the Incident x On September 2, 1973, during routine surveillance testing the

/ CSS-kop I appeared to be unable to deliver required flow at the required system pressure in the toruc-to-torus test mode.

The reactor was in the cold-shutdown condition during preparations for initial nuclear heatup and the CSS was not required.

l Investigation and Corrective Action

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Flow in each CSS loop is measured by a GE/MAC 555 flow transmitter.

Upon apparent failure of CSS-kop I, the f1cv trancmitter for CSS-kop I was checked. The "as found" test results indicated a zero offset of approximately 2-1/2 percent. The transmitter was recalibrated and the CSS-kop I curve 111ance test was repeated

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Mr. John F. O'Irary September 12, 1973 TENNESSEE VALLEY NJTHORITY - BBC'JNS FERRY NUCLEAR PLAI.T UNIT 1 -

DOCKET NO. 50-259 - FACILITY OPERATING LICENSE DPR nBNOP2!AL OCCURREUCE REPORT EFAO-737'd and all test recults were catisfactory. CSS flow instruments were originally scheduled for annual calibration; and this flow transmitter vac last calibrated on June 11, 1973 Previous calibration data did not indicate an offset error. The cause of this instrument error is not kno'vn, but Pydraulic surging during system startup and chutdown is suspected. Calibration of the CSS-Loop II flow transmitter was checked and found to have about 1/2 percent offcet in the same low direction at zero, which is within acceptable tolerance.

The CSS-Icop I was never incapable of delivering required flow at required precsure. The reported failure was in a flow instrament installed in a lcop used for curve 111ance test purposes only.

The scheduled periodic calibration frequency for the CSS flow trancaitterc has been changed to bimonthly. This schedule vill 1, be adjusted back to the original calibration frequency if data l for three cuccessive calibrations are found to be within instrument accuracy.

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Very truly yours, l TENNESSEE VALLEY AUTHORITY E. F. Thenas Director of Power Production CC: Mr. Norman C. Moseley, Director Region II Regulatory Operations Office, USAEC 230 Peachtree Street, NW.

Atlanta, Geor$1a 30303

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