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 Issue dateTitleTopic
ML20046C0823 August 1993LER 93-012-00:on 930510,reported Unusual Noise Due to Small Frictional Force Release in RCS During heat-up.Developed & Implemented Enhanced Thermal Expansion Monitoring Program. W/930803 LtrOperating Basis Earthquake
Power change
ML20045F14530 June 1993LER 93-011-00:on 930518,nuclear Plant Instrumentation Sys Axial Flux Difference Limits Were Not Updated W/Ts Due to Inadequate Review of Colr.Initiated WR & Computer Software Mod request.W/930630 Ltr
ML20044H0752 June 1993LER 93-010-00:on 930508,Mode 3 Entered from Mode 4 W/Both MDAFWPs Rendered Inoperable by Handswitches Being Placed in pull-to-lock.Caused by Failure to Control Work Activity.Mgt Expectations clarified.W/930602 LtrTemporary Modification
ML20045A4931 June 1993LER 93-009-00:on 930504,noted That Supervising Operator Erroneously Instructed RO to Reset Steamline LP SI Signal Rather than Block SI Signal.Caused by Personnel Error. Personnel Have Been Directed to Review event.W/930601 Ltr
ML20044D28211 May 1993LER 93-007-00:on 930413,determined That Surveillance Test Procedure Re RHR Sys Inservice Pump B Test Not Accomplished by 930410.Caused by Lack of Oversight of Surveillance program.Past-due Notice proceduralized.W/930511 LtrTime of Discovery
ML20045H26331 December 1992LER 92-007-01:on 920326,hot Particle Discovered on Individual Left Cheek.Event Probably Occurred During Use of Plant Communications Equipment.Procedure RPP 02-510 Evaluated
ML20045H27027 April 1992LER 92-007-00:on 920326,hot Particle Picked Up During RCS Shim Restraint Rework Insp Results in Exposure Exceeding 10CFR20.101 Requirements.Hot Particle Control Program & Policies Being reviewed.W/920427 Ltr
ML20024G97910 May 1991LER 90-026-00:on 901123,tech Spec Violation Occurred Re Safety Related Class IE Battery Bank Powered from Spare Battery Charger.Caused by Error in Safety Evaluation for Procedure Mce E051Q-01.Procedure deleted.W/910510 LtrSafe Shutdown
ML20029B23628 February 1991LER 91-025-01:on 901223,common Min Flow Path Return Line for SI Pumps to RWST Frozen.Caused by Faulty Ambient Temp Switch.Switches Calibr to Insure Heat Trace Circuits & Alarms activated.W/910228 LtrSafe Shutdown
Boric Acid
ML20029A64826 February 1991LER 91-002-00:on 910128,essential Svc Water Flow to Containment Cooling Units Below TS 4.6.2.3 Requirements of 4,000 Gpm.Caused by Inaccurate Flow Readings Provided by Local Annubars.Surveillance Procedure revised.W/910226 Ltr
ML20028H69022 January 1991LER 90-025-00:on 901223,determined That Common Min Flow Path Return Line for SI Pumps to Refueling Water Storage Tank Frozen.Cause Undetermined.Need for Effective Communications Will Be Reiterated to Plant personnel.W/910122 LtrBoric Acid
ML20028H43628 December 1990LER 90-024-00:on 901129,portion of Contents of Waste Gas Decay Tank 6 Discharged While Maint Performed.Caused by Personnel Error.Shift Supervisor counseled.W/901228 Ltr
ML20028G91926 September 1990LER 90-020-00:on 900827,portable Sump Pump Installed W/Pump Discharge Directed to Storm Drains,Bypassing Turbine Bldg Drain Monitor LE-RE-59.Caused by Lack of Communication Between Involved groups.W/900926 Ltr
ML20043H72018 June 1990LER 90-012-00:on 900517,reactor Trip,Main Turbine Trip & Auxiliary Feedwater Actuation Signals Occurred.Caused by Steam Generator C Atmospheric Dump Valve Stuck Open. Converter Positioner Circuitry replaced.W/900618 Ltr
ML20043H15318 June 1990LER 90-013-00:on 900519,main Turbine Trip Occurred as Result of hi-hi Moisture Separator Reheater Level.Root Cause Investigation Not Conclusive.Cautions Added to General Operating Procedure Gen 00-004.W/900618 Ltr
ML20043G27615 June 1990LER 90-010-00:on 900516,discovered That Insp Access Door for Motor Driven Auxiliary Feedwater Pump B Room Cooler Had Been Removed.Caused by Personnel Error.Maint Personnel Informed of Necessity of Doors Being in place.W/900615 Ltr
ML20043G07413 June 1990LER 90-011-00:on 900514,feedwater Isolation Signal & Main Turbine Trip Signal Occurred When Steam Generator B Reached hi-hi Level Setpoint & Generator C Reached lo-lo Setpoint. Caused by Power Oscillations.Procedure revised.W/900613 Ltr
ML20043G1998 June 1990LER 90-007-00:on 900510,feedwater Isolation Signal Occurred Due to Surveillance Test Requiring High Feed Rate.Caused by Feedwater Flow Rate Higher than Steam Flow.Rev to Surveillance Test Procedures clarified.W/900608 Ltr
ML20043E9558 June 1990LER 90-009-00:on 900608,discovered That Circuit Breakers for Accumulator Outlet IV Closed Resulting in Two Inoperable Accumulators.Caused by Personnel Error & Lack of Specific Procedural Direction.Procedure revised.W/900608 Ltr
ML20043F1584 June 1990LER 90-008-00:on 900504,fuel Bldg/Control Room Ventilation Isolation Signals Received from Exhaust Radiation Monitor. Caused by Burned Out Lamp & Blown Fuse in Power Supply.Fuse & Lamp Replaced & Monitor Returned to svc.W/900604 Ltr
ML20043A67316 May 1990LER 90-006-00:on 900416,containment Purge Isolation Signal & Control Room Ventilation Isolation Signal Occurred.Caused by Inadequate Procedures to Govern Deenergization of 120- Volt Ac Distribution Ctrs.Procedures revised.W/900516 Ltr
ML20042G91710 May 1990LER 90-005-00:on 900410,control Bldg/Auxiliary Bldg Pressure Boundary Door Found Open W/O Continuous Watch Established. Caused by Inadequate Procedures.Fire Protection Impairment Control Procedure revised.W/900510 LtrHourly Fire Watch
ML20042G2137 May 1990LER 90-004-00:on 900405,Tech Spec Surveillance Requirement Not Satisfied Because of Personnel Error in Scheduling Surveillance Test.Procedure Adm 02-300 revised.W/900507 Ltr
ML20042E18513 April 1990LER 90-002-00:on 900314,determined That Halon Release in Either ESF Switchgear Room Would Trip Both Class 1E Electrical Equipment Air Conditioning Units.Caused by Lack of Design Criteria.Criteria revised.W/900413 LtrFire Watch
ML20043H2879 April 1990Corrected LER 85-058-01:on 850731,reactor Trip,Main Turbine Trip,Auxiliary Feedwater Actuation,Feedwater Isolation & Steam Generator Blowdown & Sample Isolation Occurred.Caused by Faulty Power Supply to Channel.Power ReplacedFire Watch
ML20012B4338 March 1990LER 90-001-00:on 900206,reactor Tripped as Result of Loop Low Flow Condition Following Trip of Reactor Coolant Pump a, Causing Feedwater Isolation & Auxiliary Feedwater Actuation Signals.Caused by High Differential current.W/900308 Ltr
ML20012B4745 March 1990LER 88-007-01:on 880513,determined That Procedures for Setting Trip Point for Overpower & Overtemp Differential Instrument Loops Did Not Require Setpoints to Be Reset Conservatively.Setpoints recalculated.W/900305 Ltr
ML20011D43918 December 1989LER 89-020-00:on 891117,determined That as-built Configuration of Housing for Both Trains of Containment Cooling Fan HXs Not Seismically Qualified to Withstand Sse. Addl Seismic Restraints installed.W/891218 LtrSafe Shutdown Earthquake
Earthquake
ML19332F91114 December 1989LER 89-021-03:on 881025,preliminary Investigations Indicated That Containment Cooling Fan B Could Not Be Relied on to Perform Intended Design Function.Motor Overcurrent Condition Existed Since installation.W/891214 Ltr
ML19325D52618 October 1989LER 89-019-00:on 890919,determined That No Procedural Problem Existed & Equipment Problem Caused 890915 Test Deficiency.Caused by Reaching Incorrect Conclusion.Train Restored to Svc After Replacement of relay.W/891018 Ltr
ML19341D80715 January 1988LER 87-056-00:on 871215,one 400 Uci Sr-90/Y-90 Source Could Not Be Located.Caused by Inadequate Control of Licensed matl.Fan-Shaped Apparatuses Removed from Svc to Prevent recurrence.W/880115 LtrTime of Discovery