ML20085G438

AO BFAO-735W:on 730813,111.5 Psid Setpoint for Pressure Switch PdIS-1-36A of Main Steamline C High Flow Exceeded Tech Spec Limit of 108.75 Psid.Cause of Setpoint Drift Not Determined.Switch Reset

ML20085G438
Person / Time
Site:	Browns Ferry
Issue date:	08/23/1973
From:	Eric Thomas TENNESSEE VALLEY AUTHORITY
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085G442	List: ML20085G438 ML20085G464
References
AO-BFAO-735W, BFAO-735W, NUDOCS 8308290088
Download: ML20085G438 (2)

Text

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TENNESSEE VALLEY AUTHOAITY CHAs a ANOOGA, TENNESSEE !i C'~ m' ~7/'

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$ N N 5 5 U E 9,N PARTNEASHfA August 23, 1973 2 AUGn y

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.[/ yj([/[y,e[+t~ g Mr. John F. O'Icari, Director ~c

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Dear Mr. O' Leary:

TENNFSSEE VALLEY AUTHORITY - BROWNS FERRY NUCLEAR PLAUT UNIT 1 -

DOCKET NO. 50-259 - FACILITY OPERATING LICENSE DPR ABNORMAL OCCURRESCE REPORT BFAO-735W The purpose of this report is to provide details concerning the failure of a pressure switch at Browns Ferry Nuclear Plant on August 13, 1973 This occurrence was reported to the AEC Regulatory Operations Inspector by telephone on August 13, 1973, and by telegram on August 14, 1973 s

Description of Incident During monthly routine surveillance testing, pressure switch PdIS-1-36A, main steamline "C" high flow, did not operate at its technical specification stitpoint of less than, or equal to, 140-percent rated steamflow which corresponds to 108 75 psid.

The as-found setpoint was 111 5 psid. The reactor was in a cold, open-vessel condition in preparation for initial criticality.

Investigation and Corrective Action The pressure switch is a part of th'e one out of two taken twice, initiation logic ir. the main steamline isolation valve isolation system. There are four pressure switches on each steamline. The switches are Barton Model 278 differential pressure indicating switches with a range of 0 to 150 psid. The inv stigation did

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2 Mr. John F. O' Leary August 23, 1973 - .

TENIGSSEE VALLEY AUTEORITY - BROWNS FERRY HUCLEAR PLANT UNIT 1 -

DOCKET NO. 50-259 - FACILITY OPERATING LICENSE DPR ABNOPML OCCURRENCd REPORT EFAO-735W not indicate any reason that would account for the setpoint drift.

The switch was within the proper accuracy when previously tested on July 17, 1973 The test standard was within its calibration interval, and a recheck confinned its accuracy. The pressure switch was reset to 106 5 psid and operated several times to ensure repeatability.

This is not considered a violatica since the reactor has never been critical and steca has not been generated from nuclear heat.

This report is made to provide infon ation data for your instruncat reliability record system.

Very truly yours, TENNESSEE VALLEY AUTHORITY s W

E. F. Thocas Director of Power Production CC: Mr. Honaan C. Moseley, Director Region II Regtiatory Operations Office, USAEC 230 Peachtree Street, IN.

Atlanta, Georgia 30303

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