ML20085M273
| 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: |
| References | |
| AO-BFAO-741W, NUDOCS 8311080164 | |
| Download: ML20085M273 (3) | |
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TENNESSEE VALLEY AUTHO AITY r""*2M
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CHATTANOOGA, TENNESSEE 374Q1 sJ
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nL ANNNEAS 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, 27 "
TENNESSEE VALLEY AUTHORITY Y
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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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8311080164 740115 d
PDR ADOCK 05000259 l
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n.g 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.
Corrective Action
.,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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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.
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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