ML20085G145

AO BFAO-7328W:on 731017,HPCI Condensate Header Low Level Switches LS-73-56A & B Exceeded Tech Spec Limit.Caused by Sluggish Switch Spring Mechanisms.Wider Air Gap Established, Switches Reset & Test Frequency Increased

ML20085G145
Person / Time
Site:	Browns Ferry
Issue date:	10/26/1973
From:	Eric Thomas TENNESSEE VALLEY AUTHORITY
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085G136	List: ML20085G145 ML20085G154
References
AO-BFAO-7328W, NUDOCS 8308240314
Download: ML20085G145 (2)

Text

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 !                                                              e.u,,y/pr                                    i p/h Mr. John F. O'Icary, Director                   \2       czr l        Directorate of Licensing Office of Regulation
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s dJg g' l U.S. Atomic Energy Ccamission NW A g, Washington, DC 205!+5 Dear Mr. O'Ieary

TENIESSEE VALIEY AUT-:0RITY - BRC',GS FERRY !;UCEAR PLAI;T UNIT 1 -

l DOCIGT NO. 50-259 - FACILITY OPERATING LICENSE DPR ABNOW.AL OCCURRENCE REPORT BFAO-7326W The purpose of this report is to provide details concerning the malfunction of level switches at Browns Ferry Nuclear Plant unit 1

.        on October 17, 1973      This occurrence was reported by telegram on
;        October 18 to the Regica II Directorate of Regulatory Operations, i        Atlanta, Georgia.

Description cf the Incident . During routine surveillance testing on October 17, HPCI condensate header low level. switches E-73-56A and B vere found to operate outside the tecnnical specification trip level setting specified in table 3 2.B of equal to or greater than elevation 551 feet. - Investigation and Corrective Action The level switches are arranged in a one out of two logic. Either switch will initiate transfer of the EPCI suction from the condensate _ storage tank to the suppression chamber. Both switches were found inoperative and the transfer logic would not have operated. A simple adjustment of spring tensica made switch IS-73-56A operable. The switches are Robertshav model 83481 Levelac level switches. Both level switches were inspected and the switch-spring mechanisms found to be sluggish. The switch-spring mechanis=s were adjusted to obtain a positive snap action. In addition, residual magnetism was R evident in the mounting plate of switch IS-73-56B, which would contribute $ toward erratic switch operation. A vider airgap was established to 8308240314 731126 PDR S ADOCK 05000259 pyg ,. f Q

i...... - . O 9 yi i I 2 l 9 Mr. John F. O'Icary October 26, 1973 - TENNESSEE VALIl:Y AUT'{CRITY - BRO',CS FERRY :;UCLEAR PIJJ;T UNIT 1 - DOCKET I'O. 50-259 - FACILITY OPERATING LICE::SE DPR AENOR'4AL OCCURRENCE REPORT EFAO-7328W help eliminate this problem. The level switches were reset and operated several tines to ensure repeatability. These switches will be functionally tested once every 2 ueeks until three ccnsecutive tects prove satisfactory perfonnance. Very truly yours, TEUUESSEE VALLEY A'JTEORITY

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E. F. Thomas Director of Power Production CC: Mr. Ho: nan C. Moseley, Director Re61 on II Regulatory Operations Office', USAEC 230 Penchtree Street, IN. Atlanta, Georgia 30303

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