ML20085G229

AO BFAO-7326W:on 731015,trip Settings of Differential Pressure Switches PdIS-68-85,PdIS-68-89 & PdIS-68-90 Exceeded Tech Spec Limit.Switches Recalibr & Frequency of Testing Increased to Once Every 2 Wks

ML20085G229
Person / Time
Site:	Browns Ferry
Issue date:	10/25/1973
From:	Eric Thomas TENNESSEE VALLEY AUTHORITY
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085G234	List: ML20085G229 ML20085G247
References
BFAO-7326W, NUDOCS 8308240707
Download: ML20085G229 (2)

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TENNESSEE V EY AUTHO AITY E- ' 3 CHATTANOOGA, TENNESSEE #ir 37401 L '

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.0ctober 25, 1973  %

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Mr. John F. O'Icary, Director 7. u n..f,H 'cdQ

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Que Directorate of Licensing E * ,-l.$ V, Office of Regulation '

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U.S. Atomic Energy Commission f ,.

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k'ashington, DC 20545

Dear Mr. O' Leary:

TE:C;ESSEE V.aTT"? AUTEORITY - ERCh':!S FERRY IiUCLEAR PIJJIT U; TIT 1 -

DOCET I 0 50-259 - FACILITY OPERATI!!G LICE !SE DPR AB:rCRMAL CCC'JR C CE EPCI EFAC-7326'd The purpose of this report is to provide details concerning the malfunctions of three differential pressure switches in unit 1 LPCI logic system at Browns Ferry Iiuclear Plant on October 15, 1973 This occurrence was reported by telegram on October 16 to the Region II Directorate of Regulatog Operations, Atlanta, Geor61a.

Description of the Incident #

During routine surveillance testing on Oct$ber 15, three differential pressure switches, PdIS-68-85, PdIS-68-89, and PdIS-68-90, vere found '

to operate outside the technical cpecification trip setting of equal to or less than 2.0 psid as specified- in Table 3 2.B. The as-found setpoints were as follows:

PdIS-68-85--------2.06 psid PdIS-68-89--------2.13 psid PdIS-68-90--------2.10 psid

- , . .G Investigation and Corrective Action The differential pressure switches each operate a ielay having two sets of contcets. These contacts are arranged in a one out of two taken four times lcgic for each trip system. The minimum number of channels required per trip cystem is two, and system performance was not compromised. At no time vas,the minimua nu:ber of channels exceeded, and the system would have perfo: ed it.s designed purpocc. These switches hcd been functicnally tc:t i en 12ptc.f;er 21 cn.1 fcuni saticractor;c. This logic contributes to loop selection of the LFCI mode of the RER system.

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PDR ADOCK8308240707 S 05000259 731025 mpy SENT pEGION Z' PDR

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Mr. John F. O'Iqary October 25, 1973 < .

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TENNESSEE VALEY NJTEORITY - BROWNS FERRY UUCLEAR PIANT UNIT 1 -

. DOCKET UO. 50-259 - FACILITY OPERATING LICENSE DPR ABUORIAL l OCCURRENCE REPO R BFAO-7326W l

The switches, Earton Model 288 differential pressure indicating switches, have a range of zero to 10 pounds differential. The switches were inspected for satisfactory clearance and freedom of operation and recalibrated to the rec _uired setpoint, allowing for instrument accuracy.

Several operations of the switches were perfomed to ensure operability.

All of the instru:ents of the loop selection function vill be ,

scheduled for testing once every 2 vecks until three consecutive tests prove satisfactory performance. At that time, the original test

. schedule of once a conth will be resumed.

New locking switchplate assemblies to prevent setpoint drift are bein6 made available by the vendor. They will be installed as soon as possible.

Very truly yours, ,

TEN:"EC' VALL2' An'.CRITY o

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91irector of Power Production CC: Mr. Noman C. Moseley, ",lrector Re61 on II Regulatcry Cperations Cffice, USAEC

'.',' /- 230. Ecachtree, Street, NW. . . .

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Atlanta, Georgia 30303 '

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