ML20085M644

AO BFAO-7341W:on 731116,during Accelerated Surveillance Testing,Reactor Protection Sys Water Level Switches LIS-3-203A,B & C Malfunctioned.Cause Unstated.Switches Reset & New Locking Assembly Installed

ML20085M644
Person / Time
Site:	Browns Ferry
Issue date:	11/26/1973
From:	Eric Thomas TENNESSEE VALLEY AUTHORITY
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085M645	List: ML20085M644 ML20085M647
References
AO-BFAO-7341W, NUDOCS 8311090127
Download: ML20085M644 (3)

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TENNESSEE VALLEY AUTHO AITY Mg' '/ o CHATTANOOGA, TENNESSEE  :

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November 26, 1973 FTy' , $PEEEEEE PARTN TI A S Hip t .

y Mr. John F. O'Icary, Director Directorate of Licensing

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Qf Office of Regulation U.S. Atomic dnergy Commission 4

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Dear Mr. O'Icaq:

TE:EIESSE3 VALL".Y AUTHORITY - ERGW;IS ITRRY UUCIZAR PIAIE U?!1T 1 -

DOCKET I;O. 50-259 - FACILITY CPEalTI';G IlCEliSE DPR AE30 MAL OCCUR:C:CE P2PCRI EFAO-7341W The enclosed report is to provide details concerning reactor protection system vater-level switch malfunction which occurred on Ercvns Ferry Nuclear Plant unit 1 on November 16, 1973, and is submitted in accordance with Appendix A to Regulatory Guide 1.16, Revision 1, October 1973 Very truly yours, TEN:ESSEE VALLEY AUTHORITY l/

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<- x Thomas

[Di,iectorofPowerProduction Enclosure CC (Enclosure):

Mr. Nonaan C. Moseley, Director Region II Regulatory Operations Office, USAEC

, 230 Peachtree Street, IRT. .

! Atlanta, Georgia 30303

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Report No.--BFAO-7341W Report Date--Hovenber 26, 1973 Occurrence Date--Hovember 16, 1973 Facility--Browns Ferry nuelcar Plant unit 1 Identification of Occurrence Unit 1 reactor protection system vater-level switch malfunction.

Conditions Prior to Occurrence Reactor at 30-percent power, 250 nte during startup test program.

Description of Occurrence During accelerated surveillance testing on Novenber 16, 1973, rcactor water-level switches LIS-3-203A, B, and C vere found to operate outside technical specification setpoint limits. LIS 3-203A and C high level technical specification setpoint is -

less than or equal to 583 inches and were found to operate at 583 5 inches and 585 inches, respectively. LIS-3-203B was found to exceed the low-level setpoint of greater than or equal to 538 inches. It was found to operate at 537 inches.

r Analysis of Occurrence -

The contacts of LIS-3-293A and C are arranged in series to trip the RCIC turbine on high water level. Although both suitches operated outside the technical specification limit, the RCIC would have tripped on high voter level 1-1/2 inches above the trip setting. The other three low level channels were tested and found to operate satisfactorily. If the RPS had been required, it would have performed its intended function.

Corrective Action - 4 Locking plate assemblics have been received and are beingfinstalled in all Barton -

Model 288 switches. An accelerated testing frequency of once a week has been initiated and vill continue until three consecutive' tests prove satisfactory.

The testing frequency vill then continue on a biveckly schedule until three bivcekly tests are satisfactory, whereupon the or1 81nal schedule vill be resumed.

Fhilure Data Barton Model 288 Serial Nos.: LIS-3-203A, 288A-9958; LIG-3-203B, 288A-9959; LIS-3-203C, 288A-9960.

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Svftch Inte Fa flure Correetive Action LIS-3-203B 10/9/73 Operated Outside tech Reset switch to setpoint spec limit LIS-3-203c 10/9/73 Operated outside tech Rese't switch to setpoint spec limit LIS-3-203B 11/8/73 Operated outside tech Reset switch to setpoint spec limit LIS-3-203c 11/8/73 Operated outside tech Reset switch to setpoint spec limit LIS-3-203A 11/16/73 Operated outside tech Installing nev locking spec limit assembly LIS-3-2033 11/16/73 operated outside tech Installing nev locking spec limit assembly LIS-3-203c 11/16/73 Operated outside tech Installing nev locking spec limit assembly l

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