ML20085M273

AO BFAO-741W:on 740106,during Startup Test Program,Reactor Water Level Switches LIS-3-203A,B,C & D Malfunctioned.Caused by Setpoint Drift.Offset Will Be Considered in Setpoint Calibr

ML20085M273
Person / Time
Site:	Browns Ferry
Issue date:	01/15/1974
From:	Eric Thomas TENNESSEE VALLEY AUTHORITY
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085M276	List: ML20085M273 ML20085M284
References
AO-BFAO-741W, NUDOCS 8311080164
Download: ML20085M273 (3)

Text

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!' TENNESSEE VALLEY AUTHO AITY r""*2M CHATTANOOGA, TENNESSEE ( W i

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ANNNEAS nL

!, BRde' Pc7Fs",4f January 15, 1974-Mr. John F. O' Leary, Director i

Directorate of Licensing Office of Regulation U.S. Atomic Energy Comission Washington, DC 20545

Dear Mr. O' Leary:

TENNESSEE VALLEY AUTHORITY - BROWNS FERRY NUCLEAR PLANT UNIT 1 -

DOCKET NO. 50-259 - FACILITY OPERATING LICENSE DPR ABNORl/M OCCURREICE REPORT BFAO-741W The enclosed report is to provide details concerning reactor water level switch malfunction stich occurred on Browns Ferry Nuclear Plant unit 1 on January 6, 1//4, and is submitted in accordance with Appendix A to Regulatory Guide 1.16, Revision 1, October 1973.

Very truly yours, #% , '

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TENNESSEE VALLEY AUTHORITY Y N ,\

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2 E. F. Thomas

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Director of Power Production z' , j,4;f JI i

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Mr. Norman C. Moseley, Director hegion II Regulatory Operations Office, USAEC

• 230 Peachtree Street, UW.

Atlanta, Georgia 30303 i

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ABNORMAL OCCURRENCE REPORT r Report No.--BFAO-741W ,

Report Date--January 15, 1974 Occurrence Date--January 6, 1974 Facility--Browns Ferry Nuclear Plant unit 1 Identification of Occurrence Reactor water level switch nalfunction.

Conditions Prior to Occurrence Reactor at 50-percent power during startup test program.

Description of Occurrence Durin3 accelerated biweekly surveillance testing, reactor water level switches i r LIS-3-203A, 3,'C, and D were found to operate outside technical specification 9'"# -7setroint limits. LIS-3-203A and 3 high-level technical specification setpoints '

U Q . ~are less than or equal to 583. inches and were found to operate at 587 and 585

.- ; ' inches, respectively. LIS-3-203C and D low-level technical specification setpoints are greater than or equal to 538 inches and were found to operate at 537inchesand536-1/2 inches,respectively.

. Analysis of Occurrence .

The contacts of LIS-3-203A and C are arranged'in series to trip the RCIC -

turbine on high level. Althou6h switch A operated outside the technical  !

specification limit, the RCIC would have tripped 4 inches above the trip setting. The contacts of LIS-3-2033 and D are arranged in series to isolate the HPCI syste= on high water level. The automatic isolation would have occurred 2 inches above the trip setting. Both the HPCI and RCIC turbines would have tripped before gross moisture carryover could have resulted.

The low-level contacts of LIS-3-203A, B, C, and D nre arre.nged in a one out of two taken twice logic in the reactor protection system. ;Although contacts in LIS-3-203C and D operated outside the technical specification limit, contacts in LIS-3-203A and B would have performed.the low water leval trip within the technical specification limits.

1 Corrective Action .

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.,There was no apparent cause for the setpoint drift. An additional offset will l be considered in the setpoint calibration to compensate for drift. These .  !

instruments will be . checked on an accelerated frequency of once a week until three consecutive tests are satisfactory. -At that time, a biweekly accelerated '

frequency will be resumed; and, upon three consecutive tests at that frequency, the, normal, monthly frequency will be resumed. -

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O _,_ O Failure Data "

Barton bbdel 288.  ;

Serial Nos.: LIS-3-203A, 288A-9958; LIS-3-203B, 288A-9959; LIS-3-203c, 288A-9960; LIS-3-203D, 288A-9961. l Switch Date Failure Corrective Action lib-3-203B 10/9/73 Operated outside tech Reset switch to setpoint spec limit LIS-3-203c 10/9/73 Operated outside tech Reset switch to setpoint spec limit LIS-3-2033 11/8/73 Operated outside tech Reset switch to setpoint spec limit LIS-3-203c n/8/73 Operated outside tech Reset switch to setpoint spec limit LIS-3-203A 11/16/73 operated outside tech Inst-114ne new locking spec limit assembly LIS-3-2033 11/16/73 Operated outside tech Installing new locking spec limit assembly LIS-3-203c n/16/73 Operated outside tech Installing new locking spec limit assembly LIS-3-203A 1/6/74 Operated outside tech Reset switch to setpoint

• spec limit LIS-3-203B 1/6/74 Operated outside tech Reset switch to setpoint spec limit LIS-3-203c 1/6/74 operated outside tech Reset switch to setpoint spec limit

, LIS-3-203D 1/6/74 Operated outside tech Reset switch to setpoint spec limit 4

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