ML20085G000

AO BFAO-7332W:on 731031,HPCI Condensate Header Low Level Switch LS-73-56A Exceeded Tech Spec Trip Level.Switches Replaced w/1/2-ampere Switch Contacts.New Switches Will Be Replaced W/Original Type Upon Delivery

ML20085G000
Person / Time
Site:	Browns Ferry
Issue date:	11/09/1973
From:	Eric Thomas TENNESSEE VALLEY AUTHORITY
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
References
AO-BFAO-7332W, NUDOCS 8308240149
Download: ML20085G000 (3)

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TENNESSEE VALLEY AUTHO AlW r- sq-CHATTANOOGA, TENNESSEE .

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November 9, 1973 e tg SM'h'8%Pe"Z p j PAATNEASHIP B

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e Mr. John F. O'Icary, Director cm E-N v m s73 - #;i Z 1

Directorate of Licensing Office of Regulation L Sjk,' .c.' of g

U.S. Atomic Energy Cc iscion Washington, DC 20545 /,<,!w,# ,,0 # i~ *)

Dear Mr. O' Lear /:

TE:!!IESSEE VALIEY AUTHCRITY - BRCk'::S FEa.Tl NUCLEAR PUJiT U:IIT 1 -

DOCKET !!0 50-259 - FACILITY CPERATII G LICE:!SE DPR AEN0EAL OCCURRE:;CE REPCZD EFAG-7332'd The enclosed report is to provide details concerning an FFCI condensate j healer low level criten calfunction which occurred on Erowns Ferg

Nuclear Plcat unit 1 on October 31, 1973, and is submitted in cecordance

with Appendix A to Regulatog Guide 1.16, Revision 1, Cetober 1973

Very tr21y yours, TEli

:ESSEE VALLEY !.UTHORITY I, 7 T, ,sd/O nu .,

i E. F. Thena.s Director of Pcwer Production Enclosure CC (Enclosure):

l Mr. Ilomen C. Moseley, Director Region II Regulatory 0 3 rations Office, USAEC

, 230 Peachtree Street, 157 Atlanta, Georgia 30303 49 731109 l S M 05000259 > f l PDR l <

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COPY SENT REGTON

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ABNOK4AL CCCURRE: ICE REPORT Beport Ilo.--EFAO-7332W Report Date--:fovember 9,1973 Occurrence Date--October 31, 1973 Facility--Browns Ferry Ituelear Plant Identification of Occurrence Unit 1 HPCI condensate header low level switch calfunction. -

Conditions Prior to Occurrence Reactor at 30-percent power, 300 MWe, during startup test program.

Description cf Cecurrence During accelerated surveillanco testing on October 31, 1973, level switch IS-73-56A was found to operate outside technical specification trip level setting, Table 3 2.3, of equal to or greater than elevation 551 feet. Ievel switch B was tested i= ediately and operated properly. A simple' adjustment of spring tensica made switch IS-73-56A operable. The switches are Robertshaw Model 83481 levelac level switches.

Analysis of Occurrence The level switches are arranged in a one out of two logic. Either switch will initiate transfer of the EPCI suction fro = the condensate storage tank to the suppressica chamber. If required, transfer would have been initiated by the redundant switch. .

Corrective Action The vendor representative was called in to detemine the cause of the continued switch malfunctions. Theinitialswitcheswereratedat1/4 ampere /250Vd-c.

They were replaced with switches rated at 1/2 a= pere /250V d-c. (See letter from -

J. E. G111 eland to F. E. Kruesi, Director, Directorate of Regulatory Operations, AEC, dated July 18,1973.)

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Investigationindicatedthatthe1/2-ampereswitchcontactswerenotcompatible with the trip mechanism. Specifically, the new switch required a greater travel and greater pressure by the mechaniss to operate the contacts. The original type of switches will be installed as soon as they can be obtained and are s - 'suppressors installed around the level switch load to prevent arcing of these  !

i contacts. An accelerated testing frequency of once a week has been initiated l l

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for both switches. This test frequency will apply to the interim period with I l .

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the 1/2-c= pere switches and to the 1/4-c= pere switches until three consecutive tests have been accomplished satisfactorily en a weekly basis. The testing frequency vill then be increased to biveekly and the origi nal test schedule of once a month will ^ce recumed after three consecutive tests have been satisfactorily perfomed on the biveekly frequency.

i Failure Data Robertshaw Model 83481 Ievelac level switch. Serial numbers: Switch A--D-73-Io176; Switch B--D-73-Io160 Switch Date Failure Corrective Action

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LS-73-56B 6/18/73 Switch contacts / Installed higher current rating contacts failed [

IS-73-56B 8/16/73 Failed to operate Readjusted switch mechanism IS-73-56A and B 10/17/73 Failed to operate Readjusted switch mechanism a

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