05000311/LER-1991-004-02, :on 910218,radiation Monitoring Sys intermediate-range Vent Monitor 2R45B Spiked High,Causing Channel 2R41 to Deenergize.Caused by Damaged Cable Shield Connection.Detector Cable Replaced
05000272/LER-1991-003-02, :on 910209,steam Generator 14 Steamline Flow Channel I Transmitter Sensing Line Isolated During Investigation of Erroneous Readings.Caused by Personnel Error.Event Reviewed W/Personnel
05000311/LER-1991-003-01, :on 910110,leakage Noted in Svc Water Sys Charging Pump 21 Cooler Piping.On 910130,leakage Noted in Svc Water Sys Charging Pump Cooler 22 Piping.Caused by Equipment Failure.Piping Repaired
05000311/LER-1991-002, :on 910116,radiation Monitoring Sys Channel Failed.Caused by Equipment Design Concerns.Sys Design Mods Under Investigation.Channel Inspected & Repaired
05000272/LER-1991-001-02, :on 910111,containment purge/pressure-vacuum Relief Sys Isolation Signal Actuated.Caused by Equipment Failure.Channel Detector Connectors Checked & Returned to Svc
05000311/LER-1991-001, :on 910104,discovered That Hourly Roving Fire Watch Patrol for Several Areas Not Completed.Caused by Personnel Error.Responsible Individual Terminated & Event Discussed W/Appropriate Personnel
05000311/LER-1990-042, :on 901220,SWS Through Wall Leak on Inlet Pipe to Component Cooling Pump Room Cooler Occurred.Caused by Equipment Failure & Internal Corrosion.Carbon Steel Pipe Will Be Painted for Protection
05000311/LER-1990-041, :on 901206,Tech Spec 3.8.1.1 Action a Not Complied With.Required Operability Testing of 2A & 2B DG Not Performed in 8 H Due to Personnel Error.Personnel Counseled
05000272/LER-1990-037-01, On 901117,plant Vent Radioactive Noble Gas Monitor 1R41C Channel Deenergized & Failed During Investigation of 1R45 Channel Printer Failure Alarm Due to Equipment/Design Failure
05000272/LER-1990-034, :on 901005,1101 & 12,containment Purge/Pressure Vacuum Relief Sys Isolation Signals Actuated as Result of Channel Spike on Containment Particulate Monitor 1R11A. Caused by Personnel Error
05000272/LER-1990-036-01, :on 900307,Tech Spec 3.3.3.8 Noncompliance Occurred Due to Personnel Error
05000311/LER-1990-040, :on 901029,ESF Signal Actuation;Containment Ventilation Isolation Occurred Due to Equipment/Design
05000272/LER-1990-034-01, :on 901005,containment purge/pressure-vacuum Relief Sys Isolation Signal Actuated as Result of Channel Spike on Radiation Monitoring Sys
05000311/LER-1990-036, :on 900904,steam Generator Feed Pump 21 Tripped on Low Suction Pressure.Caused by Equipment Failure.Pressure Switch Replaced W/Equivalent Switch
05000354/LER-1988-014-02, :on 880511,RWCU Loop Isolated on High Flow Differential ESF Signal During Pressurization of Filter/ Demineralizer.Caused by Design & Procedure Deficiencies. RWCU Sys Operation Procedure Revised
05000354/LER-1987-048, :on 871125,trip of Safety Auxiliary Cooling Sys (Sacs) Pumps B & D & Automatic Start of Pump a Occurred. Caused by Lack of Precautions in Sacs Venting Procedure. Procedure for Venting Room Coolers Revised
05000354/LER-1987-036, :on 870804,ventilation Duct Chase Loads from Distribution Panel a de-energized.Root Cause of Occurence Under Investigation.Procedures Will Be Revised as Necessary & Battery Chargers & Inverters Investigated
05000354/LER-1987-035, :on 870804,standby Liquid Control Sys B Started,Squib Valve Fired & RWCU Isolated.Cause Undetermined.Piping Flushed & Restored to Svc & Squib Valve Replaced & Tested Satisfactory
05000354/LER-1987-033, :on 870730,unanticipated Initiation of Filtration,Recirculation & Ventilation Sys E Recirculation Fan Occurred.Caused by Dirty Contacts in Low Flow Switches of Sys Trains.Contacts cleaned.W/870831 1tr
05000354/LER-1987-030, :on 870714,HPCI Initiation Occurred While Valving in Level Transmitter on Low Pressure Side of Reactor Vessel Level Ref Leg.Caused by Design Deficiency in Transmitter.Design Change Implemented
05000354/LER-1987-034, :on 870730,reactor Scram Occurred Due to Inadvertent Deenergizing of 120 Volt Ac Uninterruptible Power Supply Inverter.Caused by Inadequate Equipment Operator Training Program.Training Upgraded
05000354/LER-1987-031, :on 870714 & 27,filtration,recirculation & Ventilation Sys Auto Initiations Occurred.Caused by Procedural Deficiency.Procedures Revised & Reviewed W/ Appropriate Staff
05000354/LER-1987-029, :on 870718,discovered That Instrument Root Valve (Irv) on RHR Pump C Discharge Line Closed.Cause Could Not Be Determined.All RHR & Core Spray Irvs to Automatic Depressurization Sys Verified to Be Open
05000354/LER-1987-050, :on 871204,determined Surveillance Missed for MSIV Outboard Steam Sealing Gas Test Line Isolation Valve on 871111 Test.Caused by Personnel Error.Procedure for Tracking Surveillance Testing Reinforced W/Personnel
05000354/LER-1987-032, :on 870729,discrepancies Discovered Between Measured & Indicated Flows for Filtration,Recirculation & Ventilation Sys (FRVS) B.Caused by Incorrect Calibr Procedure.Frvs Recalibr.Procedure Updated
05000354/LER-1987-040, :on 870910,two Isolations of RWCU Sys Occurred. Caused by High Differential Signal Due to Two Drain Valves Left Open & Personnel Errors While Placing Pump Back in Svc. Operator Counseled & Procedures Reviewed
05000354/LER-1987-046, :on 871016,initiation of Primary Containment Isolation Sys B Occurred While Swapping Reactor Protection Sys from Normal to Alternate Bus Power.Caused by Lack of Indication Alerting Operators of First Trip
05000354/LER-1987-045, :on 871007,primary Containment Isolation Sys Initiation When Restoring Power to Logic Cabinet.Caused by Spurious Logic Module Inputs.No Specific Corrective Actions Assigned
05000354/LER-1987-047, :on 871010,safety Relief Valve Failed to Close on Signal.Caused by Sand Blasting Grit in Solenoid Valve. Malfunctioning Target Rock Valve Replaced & Solenoids of Other Safety Relief Valves Inspected
05000354/LER-1987-005-03, :on 870624,loose Parts Monitor Printer Declared Inoperable After Routine Insp Revealed Problems W/Printer. New Printer Ordered But Not Received Before Expiration of 30-day Limiting Condition for Operation
05000354/LER-1987-044, :on 870925,isolation of RHR Sys Occurred During Performance of Instrument & Control Surveillance Test on Reactor Vessel Pressure Transmitter.Caused by Possible Loose Connection on Calibr Card or Wire
05000354/LER-1987-028, :on 870629 & 0701,RWCU Sys Isolation Occurred. Caused by Design Deficiencies.Procedure for Operation of Rwcs Reviewed by Chemistry Dept & Revised to Explicitly Define Valving Sequence
05000354/LER-1987-043, :on 870922,NSSSS Channel D Isolation of RHR Sys Occurred When Fuse Blown During Performance of Surveillance Procedure.Caused by Insufficient Work Space Due to Design Deficiency.Fuse Replaced
05000354/LER-1987-027, :on 870626,Channel C HPCI Isolation Occurred. Caused by Failed Temp Module.All Currently Installed Riley Tempmatic 86 Temp Modules Replaced W/Newer Model & Design Change Initiated
05000354/LER-1987-042, :on 870920,LOCA Signal Resulted in Isolation of Various Channel a Components.Caused by Leaking Instrument Valve.Instrument Isolation Valve Repaired & Sensor Calibr Procedure Reperformed Satisfactorily
05000354/LER-1987-041, :on 870910,channel Functional Test Overdue on Primary Containment Instrument Gas Sys.Caused by Personnel Unfamiliar W/New Computerized Scheduling Sys.Training in Proper Use of New Scheduling Sys Enhanced
05000354/LER-1987-026, :on 870615,motor-operated Valves Thermal Overloads Installed W/O Bypass Capability Per Tech Spec Requirement.Caused by Inadequate Design Review & Tech Spec Implementation.Design Change Initiated
05000354/LER-1987-025, :on 870611,sampling Frequency for Liquid Effluents (Composite Tritium & Gross Alpha) Required by Chemistry Dept Procedures Determined Inconsistent W/Tech Specs.Caused by Personnel Error
05000354/LER-1987-039, :on 870829,during Performance of Weekly Turbine Overspeed Protection Operbility Test,Reactor Scram Occurred. Caused by Pressure Transient Induced in Electrohydraulic Control Sys.Design Change Initiated
05000354/LER-1987-024, :on 870608,Channel a Primary Containment Isolation Sys Isolation Occurred When Two Functional Tests Being Performed at Same Time.Caused by Procedural Inadequacy.Procedures Revised
05000354/LER-1987-023, :on 870605,Tech Spec Violated Due to Drop of Emergency Diesel Generators a & B Below Min Limit.Caused by Low Pressure Alarm.Air Sys Pressure to Be Recorded Daily
05000354/LER-1987-037, :on 870816,reactor Scram & HPCI Occurred.Caused by Deficient Feedwater Sys Operating Procedure Due to Inadequate Instructions for Removing Reactor Feed Pump Turbine from Svc.Procedure Revised
05000354/LER-1987-038, :on 870818,failure to Perform Surveillance of Reactor Level Instrumentation within Period Required by Tech Specs Discovered.Caused by Personnel Error.Individual Responsible for Missed Surveillance Counseled
05000354/LER-1987-004-03, :on 870610,north Plant Vent High Flow Sample Pump Inoperable for More than 72 H.Caused by Equipment Failure.Spare Parts for Equipment Problem on Order & Should Be Installed by 870627
05000354/LER-1987-021, :on 870508,ESF Actuation Occurred When Reactor Protection Sys Bus a de-energized.Caused by Design Deficiency Re Use of Nonregulated Transformer.Regulating Transformer Will Be Installed
05000354/LER-1987-022, :on 870509,cooling Tower Blowdown Radiation Monitoring Sys Sample Pump Found Out of Svc for Greater than 12 H & Required Grab Samples Not Taken.Caused by Personnel Error.Technician Counseled & Retrained
05000354/LER-1987-020, :on 870421,while Shift Chemistry Technician Attempting to Place RWCU Filter/Demineralizer B in Hold Mode,Steam Leak Isolation Timer Initiated on High Differential Flow.Caused by Personnel Error
05000354/LER-1988-015, :on 880526,unanticipated Loss of Second Control Room Emergency Filtration Chiller Occurred.Caused by Component Design Deficiency.Operation Procedure Reviewed & Design Mod to Chiller Installed
05000354/LER-1988-012, :on 880430,reactor Manually Scrammed Following Circulating Water Sys (CWS) Infeeds Trip.Caused by Failure in CWS Multiplex (Mux) Sys.Replacement of CWS Mux Sys W/Hard Wired Sys Planned & Enhanced Maint Developed
05000354/LER-1988-010, :on 880414,two HPCI Oil Control Valves Discovered Not to Be in Required Position for Operability. Caused by Unauthorized Repositioning of Valves.Valves Restored to Required Position & Signs Posted
05000354/LER-1988-011, :on 880426,discovered That Seismically Unqualified Tubing Spans Installed on Two Local Instrument Racks.Caused by Personnel Faulty Preparation of Design Change Which Installed Tubing W/O Requirements
05000354/LER-1988-009-01, :on 880413,reported That Contrary to Tech Spec Requirement,Two 4-h Flow Rate Estimates Not Made During South Plant Vent Monitor Outage.Caused by Operator Failure to Initiate & Complete Daily Log
05000354/LER-1987-036-01, :on 870804,channel a Class 1E 125 Volt DC Loads from Distribution on Panel a de-energized During Operational Condition 1.Root Cause Not Determined.Breakers for Affected Sys Opened & Reset.Procedures Revised
05000354/LER-1988-008-01, :on 880401,caulking Matl Discovered Around Reactor Bldg Blowout Panels.Caused by Installation of Caulking W/O Design Change Authorization & Personnel Error. Unauthorized Caulking Removed
05000354/LER-1988-007-01, :on 880330,reactor Protection Sys Actuation Occurred.Caused by Workers Installing Design Change in Area Near Intermediate Range Monitor Preamplifier Cabinet.Warning Signs Posted
05000354/LER-1988-019, :on 880728,Channel C ECCS Level 1 Actuation Occurred During Functional Testing of Reactor Vessel Level Channel Causing Actuation of Emergency Diesel Generator & LOCA Sequencer.Caused by Procedural Deficiency
05000354/LER-1988-018, :on 880725,unanticipated Isolation of RWCU Occurred W/Plant in Operational Condition 1.Caused by Blown Fuse in Channel a of Nuclear Steam Supply Shutoff Sys.Fuse Replaced & Personnel Counseled
05000354/LER-1988-006-01, :on 880321,momentary Upscale Spike on Intermediate Range Monitor Resulted in Full Reactor Protection Sys Actuation.Caused by Electronic Noise Generated by Welders.Methods Evaluated
05000354/LER-1988-003, :on 880220,primary Containment Leakage Rate Determined to Be in Excess of Tech Spec Limit.Caused by Hairline Crack on Inboard Check Valve Seat & Irregularities in Outboard Check Valve Seat.Valves Adjusted
05000354/LER-1988-005, :on 880310,primary Containment Isolation Sys Inputs Inoperable & Required Tech Specs Actions Not Taken. Caused by Inadequate Design Change Package (DCP) Description.Secondary Containment Established
05000354/LER-1988-016, :on 880616,unanticipated Primary Containment & Control Room Emergency Filtration Initiation Occurred.Caused by Momentary Power Loss Due to Inverter Malfunction During Switching.High Voltage Power Supply Replaced
05000354/LER-1988-002-02, :on 880213,primary Containment Leak Rate Testing of Recirculation Sample Inboard Isolation Valve Overdue.Caused by Personnel Error.Event Will Be Reviewed as Stated When Preparing First Refuel Outage
05000354/LER-1988-001-01, :on 880106 & 28,liguid & Gaseous Radwaste Discharge Monitors Failed to Pass Functional Tests.Caused by Design & Procedure Deficiencies.Gaseous Radwaste Monitor Surveillance Procedures Revised
05000354/LER-1988-002, :on 880213,primary Containment Isolation Valves Inoperable.Caused by Failure of Inservice Insp to Notify Control Room Personnel That Surveillance Overdue.Both Inboard & Outboard Valves Reworked
05000354/LER-1988-004-02, :on 880301,discovered That Required Surveillance of Refueling Floor Exhaust Process Radiation Monitoring Channel B Not Performed.Caused by Personnel Error.Senior Supervisor Counseled
05000354/LER-1988-003-01, :on 880220,primary Containment Leak Rate Determined in Excess of Tech Spec Levels.Caused by Cracked Stellite on AE-V003 Disk & Worn Disk Hinge Pin.Valves Repaired & Review of Event Planned
05000354/LER-1987-052, :on 871210,isolation of RWCU Sys Occurred While Pressurizing Filter/Demineralizer (F/D) B.Caused by F/D Design Deficiency.Procedures Changed & Design Change Scheduled for 1988 Outage
05000354/LER-1987-051, :on 871208,automatic Reactor Scram Occurred. Caused by Grounding of Cabinets C & D Which Provided Path for Spurious Signal.Personnel Instructed & Monitor Grounding Configuration Analyzed
05000272/LER-1990-035-01, :on 901005,discovered That Position Indication Surveillance for Pressurizer PORVs & Block Valves Not Performed,Per Tech Spec Table 4.3-11
05000272/LER-1991-011, :on 910220,high Rad Area Found Unlocked & Unguarded.Caused by Personnel Error.Event Reviewed by Radiation Protection Dept & Corrective Action Taken Against Technician Responsible
05000311/LER-1991-005-02, :on 910226,sustained Undervoltage Relay Min Drop Out Trip Setpoints Set Below Tech Spec Value.Caused by Personnel Error & Procedural Inadequacy.New Relay Procedures Implemented
05000311/LER-1991-006-01, :on 910302,ESF Actuation,Automatic Switching of Control Room Ventilation to Emergency Mode of Operation Occurred.Caused by Equipment Failure.Channel Detector Cable Connection Rebuilt
05000272/LER-1991-010, :on 910220 & 0304,containment Purge/Pressure Vacuum Relief Sys Isolation Signals Actuated & Channel 1R12A Alarmed.Caused by Procedure Inadequacy.Alarm Point Procedure Revised
05000272/LER-1990-040-01, :on 901112,ground Fault Indication Received in Control Room for Both B & C 125-volt Dc Vital Busses Due to Installation of 125-volt Ac Struthers Dunn Relay Coil.Caused by Personnel Error.Event Reviewed
05000272/LER-1991-002-02, :on 910117,RHR Pump 11 Room Cooler Leakage Noted on Metal Weld of Inlet Control Valve.On 910124,leakage Noted on SI Pump Room Cooler & Auxiliary Feedwater Pump Cooler.Caused by Equipment Failure
05000272/LER-1991-006, :on 910216,20 & 27,containment Purge/Pressure Vacuum Relief Sys Isolation Occurred & Actuation Signals Initiated by Radiation Monitor Channel.Caused by Inadequate Administrative Controls.Channel Reset
05000272/LER-1991-007, :on 910217,motor Driven Auxiliary Feedwater Automatically Started After Distribution Cabinet 1CCDC Power Supply Transferred to Emergency Power Supply.Caused by Inadequate Administrative Controls
05000311/LER-1990-025, :on 900525,environ Qualification Noncompliance Concern of Main Steam Vent Valve Control Panel Noted Due to Inadequate Design Review
05000311/LER-1990-029, :on 900628,reactor Trip Occurred Following Loss of Generator Feedwater Pumps Resulting from Failure of Volt Transformer.Caused by Inadequate Preventive Maint.Design Change Concerns Reviewed by Mgt
05000272/LER-1990-039-01, :on 901214,radiation Monitoring Sys Channel Caused ESF Actuation Signal for purge/pressure-vacuum Relief Sys Isolation.Caused by Personnel Error.Event Reviewed & Disciplinary Action Taken
05000311/LER-1990-044, :on 901223,containment purge/pressure-vacuum Relief Sys Isolation Signals Received.Caused by Equipment/ Design Concerns.Microprocessor Pin Connections Cleaned & Tightened
05000311/LER-1990-038, :on 901004,containment Particulate Radiation Monitoring Sys Channel Spiked Resulting in Containment purge/pressure-vacuum Relief Sys Isolation Signal
05000272/LER-1990-038-01, :on 901123,control Room Ventilation Automatically Switched to Accident Mode.Caused by False High Activity Alarm Signal Due to Personnel Error
05000311/LER-1990-043, :on 901220,all Control Room Analog Rod Position Indicator Indication Lost.Caused by Ribbon Cable Insulation Wearing Through to Wire.Preventive Maint Program Will Be Reviewed & Modified
05000272/LER-1990-032-01, :on 900919,sys Engineer for RMS Discovered That Alarm Setpoint for 1R13A & 1R13B RMS Channels Not Correct
05000272/LER-1990-031-01, :on 900917,ESF Actuation;Control Room Ventilation Switchover Occurred Due to Equipment Failure
05000272/LER-1990-033-01, :on 900923,two Channels Made Inoperable Due to Equipment Failure
05000272/LER-1990-026, :on 901130,leakage of ASME Code Class 2 & 3 Piping Occurred.Caused by Equipment Failure.Piping Upgrade Continuing & Pipe Replacement Reviewed & Modified Based on Routine Insp Activites
05000272/LER-1990-030-01, :on 900910,trip on Steam Generator 13 lo-lo Level Occurred Due to Personnel Error
05000311/LER-1990-039, :on 901006,Tech Spec 3.5.2.c Noncompliance Occurred Due to Personnel Error
05000311/LER-1990-037, :on 900922,after Resetting 2C Sec (Upon Successful Completion of 2C DG 1 H Surveillance run),2C Sec Mode I Accident Safeguards Actuation Occurred
LR-N899176, Responds to Violations Noted in Insp Repts 50-272/89-15 & 50-311/89-14.Corrective Actions:Procedures Re Rod Position Indication Signal Module Calibr & Rod Drop Time Measurements Revised to Include Precautionary Note & Events Reviewed