05000259/LER-1989-012-02, :on 890505,fault in Isolated Phase Bus Duct on Secondary Side of Main Transformer 1A Occurred.Caused by Lack of Administrative Control on Operation of Bus Duct Cooling Sys.Standoff Insulators Replaced
05000382/LER-1988-030, :Since 881110,number of Discrepancies Have Been Identified in fire-rated Assemblies at Plant.Cause of Events Appears to Be Inadequate Fire Seal Installation & Insp Program During Initial Plant Const
05000369/LER-1989-019-01, :on 890821,inadvertent ESF Actuation Occurred Due to Inappropriate Action & Defective Procedure.Procedure Changes Completed for Train a & Train B Diesel Sequencer Timer Calibr Procedures
05000285/LER-1989-011, :on 890418,hourly Fire Watch Patrol at Door 1025-2 Not Performed & Penetration Seal Not Restored to Operable Status within 7 Days.Caused by Use of Uncontrolled Working List.Security Bulletin Issued
05000327/LER-1989-025, :on 890815,all Four Emergency Diesel Generators Declared Inoperable Because Fuel Oil Not Sampled.Caused by Inadequate Procedure Due to Chemistry Personnel Omission. Samples Obtained & Analyzed
05000338/LER-1989-005-01, :on 890225,unit Tripped from 76% Power When Initiating Signal for Reactor Trip Was Greater than Feedwater Flow Mismatch Coincident W/Low Steam Generator Level.Caused by Closure of Regulating Valve
05000369/LER-1988-036, :on 881118,third Test on Vg Header a Did Not Conclude Past Operability Because Blackout Header Loads During Blackout Conditions Are Unknown.Caused by Design Deficiency.Vg Sys Will Be Upgraded
05000260/LER-1989-006-01, :on 890331,unplanned ESF Actuations Occurred Due to Loss of Reactor Protection Sys Motor/Generator Output.Caused by Personnel Standing on Breaker Cabinet. Scaffold Const Procedure Revised
05000298/LER-1989-012, :on 890407,actuation of ESF Group Isolations Occurred Subsequent to Planned Manual Scram.Caused by design.State-of-the-art Digital Turbine Control Sys Being Installed
05000338/LER-1988-022, :on 881013,determined That Various Pipes in Safety Injection Sys & Chemical Vol & Control Sys Collected or Trapped Gas Which Might Affect Functions of Sys.Caused by Not Completely Venting Sys After Refill
05000334/LER-1989-007-01, :on 890518,electrical Supply Breaker to ATWS Mitigating Sys Actuation Circuitry Panel Accidentally Opened.Caused by Design Deficiency.Deficiency Corrected by Modifying Process Instrumentation Circuitry
05000328/LER-1988-041, :on 881209,discovered That as-installed Instrument Cabinets Supplied by Bailey Meter Co Did Not Meet Seismic Qualification Requirements.Caused by Lack of Two Restraint Bars on Vendor Drawings
05000317/LER-1989-003, :on 890319,operators Caused Inadvertent Actuation of ESF by Not Following Procedure step-by-step When Reinstating Block signal.INPO-assisted Formal Human Performance Evaluation Performed
05000341/LER-1987-031, :on 870720,high Vibration Signal Caused Turbine Control Valve Fast Closure & Reactor Scram Resulted.Caused by Erroneous High Vibration Signal from Faulty Shaft Rider Sensor Connection.Design Change Being Prepared
05000341/LER-1989-005, :on 890208,potential Concerns W/Secondary Containment Integrity Due to Use of non-Q Air Supply Noted, Following Test Failure.Caused by Wind Conditions Impacting Test Results.Foam Seal Installed within 4 H
05000301/LER-1989-001, :on 890203,operator Dicovered Both Supply Breakers in Open Position Due to Simultaneous Automatic Turbine Runback.Cause Not Positively Identified.Efforts Will Be Made to Ease Difficulty W/Supply Breakers
05000413/LER-1987-001, :on 870105,inadvertent Radioactive Gas Release Occurred Causing Auxiliary Bldg Ventilation Sys to Swap from Bypass to Filter Mode.Caused by Failure of Waste Gas Sys Drain Trap T-04
05000321/LER-1987-006-01, :on 870612 & 22,main Control Room Environ Control (Mcrec EIIS Code VI) Sys Went Into Pressurization Mode of Operation on Receipt of High Radiation Field Trip Signal.Caused by Irradiated Outage Equipment
05000259/LER-1988-032-01, :on 880914,discrepancies Discovered in Electrical Cable Classifications & Cable Routings Indicates Violation of Requirements.Caused by Inadequate Design Control.Design Program Improved Significantly
05000321/LER-1987-015-01, :on 870827 & 28,main Control Room Environ Control Sys Actuated on Signal from Refueling Floor Area Radiation Monitor,Resulting in 870827 Pressurization.Caused by Faulty Gm Tube.Tube Replaced
05000369/LER-1997-009, :on 970906,reactor Trip Occurred on Both Units Due to Loss of non-vital Power to Plant components.Re-closed Breaker MKA-1B,restored Kxa to Svc,Replaced Breaker MKA-1B & Repaiared Cable Connection
05000334/LER-1999-012, :on 990915,inoperability of Loop 1 Over Temperature Delta Temperature Function,Was Discovered.Caused by Personnel Error.Discussed with I&C Technicians.With
05000395/LER-1997-003, :on 970817,plant Was Entered Into TS 3.0.3. Cause Due to Less than Minimum Two Channels of OTDT Operable.Procedures Requiring Rev Due to TS Amend 75 Were Verified & Completed
05000364/LER-1998-001-05, :on 980328,manual Reactor Trip Due to Dropped Control Rod K-2,was Determined.Caused by Overcurrent Condition.Crdm Cable & Connectors Associated W/Rod K-2 Will Be Replaced & Rod Will Be Tested During Startup Testing
05000366/LER-1986-030-01, :on 860925,full Reactor Protection Sys Actuations Occurred.Caused by Static Electrical Noise. Operations Personnel Reset Actuation Signal
05000369/LER-1986-018-02, :on 860924 & 25,high Pressure Reactor Trip Occurred.Caused by Turbine Control Sys Malfunction. Troubleshooting & Testing Performed on Digital Electrohydraulic Turbine Control Sys
05000413/LER-1986-051, :on 860106,emergency Hatch Between Upper & Lower Containment Inoperable.Caused by Personnel Error. Importance of Instructions & Directions in Work Requests & Procedures Will Be Reviewed
05000341/LER-1987-018, :on 870520,during Troubleshooting of Leakage Discovered in Drywell,Rwcu Inboard Isolation Valve Isolated Twice & Outboard Isolation Valve Once.Caused by Latent Heat Migration in Sys Piping.Valve Repacked
05000267/LER-1986-026, :on 860917,FSAR Analysis for Safe Shutdown Cooling W/Firewater Invalid.Caused by Incomplete Analysis/ Inadequate Review.Review & Reanalysis Will Be Performed on Various Accidents Described in FSAR
05000366/LER-1986-017-01, :on 860915,RCIC Inboard Primary Containment Isolation Sys Valve Closed for No Apparent Reason.Caused by Spurious Electrical Noise.Valve Reopened
05000409/LER-1986-030, :on 860919,high Flux Scram Received on Nuclear Instrumentation Channel 6,causing Fast Spike from 19 to 36% of Scale.Caused by Malfunction of Instrument Channel. Replacement Nuclear Instrumentation Ordered
05000413/LER-1987-013, :on 870316,manual Reactor Trip Occurred After Main Feedwater Control Valve Failed Closed.Cause Unknown. Control Circuit Components Replaced & Tested & Reactor Trip Response Procedure Revised
05000269/LER-1986-010-04, :on 860828,potential for Lack of Pump Runout Protection During Certain Design Basis Transients Found. Caused by Failure to Analyze Emergency Feedwater Sys for All Design Basis Transients
05000370/LER-1986-010, :on 860623,containment Spray Pump 2B Declared Inoperable Due to Refueling Water Storage Tank Temp Exceeding 100 F.Pump 2A Declared Inoperable on 860619.Caused by Inadequate Procedures for Temp Monitoring
05000413/LER-1986-049, :on 860825,automatic Alignment of Nuclear Svc Water Sys to Standby Nuclear Svc Water Pond Inadvertently Occurred.Caused by Personnel Error.Sys Realigned & Transfer Switch Returned to Control Room Position
05000483/LER-1986-038, :on 861107,containment Purge Isolation Signal & Control Room Ventilation Isolation Occurred Due to Increased Gaseous Radioactivity Levels in Containment.Caused by Unanticipated Leakage from Pressurizer PORV Block Valve
05000348/LER-1987-009, :on 870510,during Performance of Svc Water (SW) Flowpath Verification,Rhr Pump 1B Room Cooler SW Isolation Valves Found Closed.Caused by Personnel Not Ensuring That Valves Repositioned.Personnel Counseled
05000409/LER-1986-025, :on 860821,containment Bldg Ventilation Isolation Occurred on High Gaseous Activity Monitor Alarm. Caused by Welding.Correlation Between Welding & Increased Gaseous Activity Checked
05000483/LER-1986-036, :on 860321,two Sealed Sources Discovered Placed Into Use W/O Performing Leak Testing.Caused by Cognitive Personnel Error.Sealed Sources Leak Tested by Vendor Prior to Shipment
05000301/LER-1986-007, :on 861009-22,eddy Current Insp of Steam Generator Tubes Conducted.Eight Tubes Degraded Equal to or Greater than 40% & Six W/Undefined Signal.All 58 Tubes Plugged
05000414/LER-1986-034-01, :on 860804,manual Reactor Trip Initiated Due to Unexpected Closure of Main Feedwater Containment Isolation Valves.Cause Unknown.Turbine Driven CA Pump Secured & Letdown Flow Reestablished
05000237/LER-1986-015-05, :on 860805,reactor Bldg Ventilation Particulate Sampler Filter Found Broken When Radiation Chemistry Technician (RCT) Attempted to Remove Filter for Counting. Caused by Improper Installation by RCT
05000259/LER-1986-027-01, :on 860731,control Room Emergency Ventilation Sys Fan a Observed Not Running Despite Completion of auto- Initiation Logic.Caused by Faulty Starter Coil.Suspected Starter Replaced
05000341/LER-1986-041, :on 861021,plant Allowed to Operate W/Drywell Sump Flow Monitoring Sys Inoperable.Caused by Inadequate Procedure Which Resulted from Cognitive Personnel Error. Surveillance Procedure Revised
05000483/LER-1987-006, :on 870413,util Received Ltr from Westinghouse Re Inaccuracy in Tech Specs for Response Times Associated W/ Safety Injection Signal.Tech Spec Change Requested & Granted on 870504
05000317/LER-1986-007-01, :on 861011,automatic Actuation of Reactor Protection Sys on High Axial Shape Index Initiated Reactor Trip.Caused by Lack of Detailed Procedural Guidance for Specific Plant Conditions
05000281/LER-1986-013-02, :on 861005,auxiliary Feedwater Pumps Started & Steam Generator Blowdown Trip Valves Closed.Caused by Cycling of Auxiliary Lube Oil Pump for Main Feed Pump (MFP) & Trip of MFP Breaker.Procedures Changed
05000281/LER-1986-014-02, :on 861010,results of Type C Containment Leakage Testing Indicated That Inside & Outside Containment Sump Trip Valves Had Leakage Greater than 300 Scfh.Caused by Erosion of Plug & Seat.Valves Will Be Replaced
05000250/LER-1986-039, :on 861227,reactor Tripped Following Loss of Turbine Electrical Load Due to Failed Turbine Governor Control Oil Pressure.Turbine Control Oil,Lube Oil & Seal Oil Piping Will Be Cleaned
05000409/LER-1987-002, :on 870216,manual Reactor Scram Following Receipt of First Out Alarm on Annunciator Scram Panel Occurred.Caused by Shorted Input Capacitor in Alarm Card. Alarm Card Replaced
05000370/LER-1986-011-03, :on 860625,auxiliary Feedwater Sys Automatically Started Due to Condensate Booster Pump Trip on False Low Flow Indication.Cause Undetermined. Pump 2B Manually Started
05000339/LER-1987-001-02, :on 870203,load Limit Setting on Emergency Diesel Generator 2H Determined to Be Incorrect.On 870206, Emergency Diesel Generator 2J Load Setting Also Incorrect. Caused by Failure to Follow Procedure
05000346/LER-1986-031, :on 860724,surveillance Requirement Interval for Station Batteries Exceeded by 9 H & 20 Minutes.Caused by Inadequate Shift Turnover & Cumbersome Test Tracking Sys. Event Discussed & Procedures Revised
05000382/LER-1986-029, :on 861228,hi-hi Alarm Occurred on Radiation Monitor ARM-IRE-0200.1S.Caused by Monitors Sensitivity to Electrical Spikes,Vibration & Light.Efforts Continuing to Reduce Sensitivity of Monitors
05000483/LER-1986-040, :on 861223,auxiliary Feedwater Actuation of motor-driven Auxiliary Feedwater Pump B Occurred.Caused by Inappropriate Human Performance.Event Discussed W/Operations Personnel
05000213/LER-1986-036, :on 860708,while Metering Charging Pump Out of Svc,Charging Pump a Taken Out of Svc Due to Broken Shaft. Caused by Metal Fatigue.Plant Placed in Hot Shutdown. Procedures Re Pumps Revised
05000458/LER-1997-007-02, :on 970926,discovered Cracked EDG Valve Adjusting Screw Assembly Swivel Pads (Vasasps).Caused by Mfg Defect.Replaced Vasasps in EDGs W/New Components & Returned Defective Vasasps to Vendor for Analysis
05000328/LER-1986-008-04, :on 861130,containment Ventilation Isolation Occurred.Caused by Personnel Error.Disciplinary Action Taken to Ensure That Instrument Mechanic Follows Procedures in Future to Prevent Recurrence
05000327/LER-1986-026, :on 860629,sudden Pressure Relay Failed on Common Station Svc Transformer D,Causing Fire Suppression Sys to Spray Transformer W/Water & Subsequent Transformer Trip.Caused by Shortened Microswitch in Relay Housing
05000312/LER-1986-013, :on 860630,0706,22 & 23,CR/TSC Essential HVAC Sys a & B Autostarted.Incidents Part of Recurring Problems W/Design,Control & Operation of Cr/Tsc Essential HVAC Sys.W/
05000409/LER-1986-035, :on 861118,failure of Low turbine-condenser Vacuum Relay SK25/1 Caused Reactor Scram W/Excessively Fast Cooldown.Caused by Failure of Allied Control,Model MHYO-12A 115-volt Ac Relay
05000302/LER-1986-021, :on 861112,emergency Feedwater Sys Actuation Occurred.Caused by Auxiliary Steam Regulating Valve Malfunction.Valve Repaired & Tested & Procedures Revised.W/
05000410/LER-1987-008, :on 870127,violation of Limiting Condition for Operation Occurred During mark-up of Carbon Dioxide Fire Suppression Sys.Caused by Misinterpretation of Communication by Personnel.Signature for Actions Required
05000328/LER-1986-007-04, :on 861111,error Discovered in Surveillance Instruction (SI) 246 Which Could Lead to Tech Spec Violation.Caused by Procedural error.SI-246 Will Be Revised & Flow Transmitters Will Be Recalibr
05000382/LER-1987-003, :on 870122,radiation Monitor Alarmed Due to Contaminated Instrument & Controls (I&C) Technician.Caused by Health Physics Technician Improperly Downgrading Work Permit Requirements.I&C Technician Retrained
05000327/LER-1987-004, :on 870113,discovered That Determination of Charcoal Adsorber Bank Efficiency by Technical Instruction TI-9 Performed Improperly.Caused by Personnel error.TI-9 Revised to Ensure Accurate Adsorber Efficiency
05000280/LER-1986-025, :on 860918 & 19,control Rods P-6 & P-10 Dropped Into Core,Respectively & Reactor Manually Tripped.Caused by Failed Stationary Gripper Coil & Loose Female Connector Pin. Parts Replaced & Control Rods Tested
05000364/LER-1986-008-01, :on 860915,failure to Post Fire Watch Per Tech Spec 3.7.11.2 Discovered.Caused by Personnel Propping Open Fire Door W/O Control Room Approval.Personnel Counseled Re Fire Door Opening Procedures
05000369/LER-1986-016-03, :on 860902,RCS Pressurizer Code Safety Relief Valve 1NC-1 Lifted W/Sys Pressure Below Required Relief Setpoint.Caused by Incorrect Setup of Valve.Valve 1NC-1 Replaced & Valve 1NC-2 Adjusted
05000250/LER-1987-003, :on 870112,annunciator E 8/3 Generator Field Ground Alarmed.Caused by Turbine Plant Cooling Water Leak in Exciter Housing.Leaking Exciter Air Cooler Isolated & Drained
05000328/LER-1987-001-02, :on 870110,discovered That Fire Breach Permit Not Written When Damaged Kaowool Found.Caused by Personnel Error.Kaowool Moved Back Into Place & Clamp Used to Hold Fire Protection Matl in Place
05000482/LER-1987-002, :on 870108,low Steamline Pressure Signal Occurred During Calibr Testing & ESF Actuation Initiated. Caused by Personnel Error.Improved Instrument Identification Tags & Procedural Enhancements Made
05000220/LER-1986-006, :on 860409,discovered That One of four-inch Sample Lines to Header Completely Plugged.Caused by Pebbles Washed Off Reactor Bldg Into Roof Drains.Roof Drain Screens Will Be Installed
05000298/LER-1986-005, :on 860227,HPCI Sys Declared Inoperable After Gasket Failure on Gland Steam Condenser.Caused by Condensate Leakage Through Condenser Top head-to-shell Joint Gasket. Condenser Repaired
05000298/LER-1987-003, :on 870107,reactor Scram & Group Isolations Occurred Due to Low Reactor Vessel Level During Troubleshooting.Caused by Insufficient Acceptance Test. Terminal Connections Verified
05000348/LER-1987-001, :on 870105,containment Atmosphere Particulate Radioactivity Monitor Discovered Inoperable Due to Improper Valve Alignment.Caused by Personnel Failure to Follow Procedures.Personnel Counseled
05000346/LER-1986-035, :on 860813,seismic Monitoring Sys Inoperable. Caused by Deficient Surveillance Test Procedures.Strong Motion Accelerometers Removed for Calibr & Test Procedures Revised to Meet Tech Specs
05000250/LER-1987-002, :on 870103,control Valve CV-3-739 Declared Out of Svc Due to Failed Solenoid Coil,Exceeding Tech Spec 3.3.3.Caused by Valve Being Left Out of Table 3.6-1.Failed Solenoid Replaced & Table 3.6-1 Revised
05000250/LER-1987-001, :on 870104,auxiliary Feedwater Pump Actuation Occurred Following Attempt to Start Steam Generator Feedwater Pump 3B.Auto-start Logic of Feedwater Pump Checked for Malfunction.Starts to Be Monitored
05000281/LER-1986-015-01, :on 861031,pressurizer Safety Valve Setpoints Found Outside Allowable Limits.Caused by Failure to Compensate for Operating Temp & Valve Wear.Valves Replaced & Setpoints Reset
05000382/LER-1987-005, :on 870211,safety Injection Tank 1B Drained to Level Below Tech Spec Limits.Caused by Procedural Inadequacies Re Narrow Range Level Instrument Ref Leg. Procedures Will Be Revised
05000410/LER-1986-019-01, :on 861215,reactor Scram Signal on Scram Discharge Vol Received Following Preplanned Scram.Caused by Operator Failure to Adhere to Scram Recovery Procedure. Procedure Revised.Training Mod Recommended
05000416/LER-1986-044, :on 861118,permanent Electrical Wire Erroneously Removed from Isolation Logic Circuit During Performance of Surveillance.Caused by Procedural Error. Procedure Revised to Delete Incorrect Step
05000328/LER-1986-010-04, :on 861203,containment Phase B Isolation Occurred During Performance of Surveillance Procedure.Caused by Deficient Procedure.Procedures Re ESF Actuations During Testing Will Be Revised
05000414/LER-1986-051-01, :on 861120,reactor Tripped on Turbine Trip Above 69% Reactor Power.Caused by Feedwater Pump Suction Flow Pressure Switch Being Out of Calibr.Work Request Initiated & Completed on Pressure Switch
05000269/LER-1986-009-02, :on 860610,discovered That Keowee Battery Racks Did Not Comply W/Seismic Design Requirements.Caused by Poor Communication & Design/Installation Deficiency.Styrofoam Cell Spacers Installed
05000281/LER-1986-019-01, :on 861201,individual Rod Position Indicators (Irpi) for Control Rods Out of Calibr.Caused by Instrument Drift.All Inoperable Irpis Recalibr & Returned to Svc
05000301/LER-1986-003, :on 860603,turbine Runback Occurred Due to Loss of Power on Instrument Bus.Caused by Trip of White Inverter Output Breaker.Procedures for Placing Inverter on Line Will Be Revised by 860901
05000382/LER-1987-009, :on 870317,discovered That Instrument Used to Determine Containment Internal Pressure Not Sufficiently Accurate.Caused by Design Deficiency.Calculational Methodology Substituted
05000382/LER-1987-010, :on 870318,discovered That Retest of Pressurizer Surge Line PSL-203 Sample Header Inside Containment Isolation Valve Not Performed.Caused by Failure to Comply W/Mgt Controls & Procedures
05000327/LER-1987-017, :on 870306,surveillance Instruction Review Identified Potential Failure to Meet Min Boron Concentrations.Caused by Inadequate Administrative Controls & Analytical Technique.Instructions Revised
05000286/LER-1986-005-01, :on 860523,turbine Trip Occurred During Monthly Surveillance Test 3PT-M12.Caused by Failed Relay in Turbine Independent Electrical Overspeed Protection Sys (Ieops). Relay Replaced & Similar Ieops Relays Tested
05000443/LER-1987-007, :on 870304,Train a Reactor Trip Breaker Inadvertently Tripped.Caused by Personnel Error.All Shifts Informed of Event to Ensure Added Caution During Future Performance of Surveillance
05000395/LER-1987-003, :on 870310,weekly Surveillance Not Performed on Diesel Fire Pump Starting Battery as Required by Tech Spec 4.7.9.1.3.Caused by Personnel Error.Event Discussed & Emphasis Placed on Timely Completion of Tests
05000364/LER-1987-001-01, :on 870228,reactor Tripped.Caused by Spike on Channel 1 of Over temp-delta-t While Channel 3 in Test. Investigation Into Cause of 7300 Series lead-lag Cards Continuing
05000410/LER-1986-012, :on 861128 & 29,series of Related Automatic Initiations of Standby Gas Treatment Sys Occurred.Caused by Clogged Filters & Personnel Error.Approx 50% of First Stage Filters Replaced & Training Mod Initiated
05000414/LER-1986-032-01, :on 860708,main Feedwater Isolation Occurred Due to hi-hi Level in Steam Generator C.Caused by Leaking Control Valves.Cf Isolation Signal Reset.Main Feedwater Pump Turbine Started
05000327/LER-1986-029, :on 850118,ERCW Pump K-A Failed to Meet Acceptance Criteria as Determined by Measured Total Flow Rate & Appropriate Baseline Curve.Caused by Personnel Error. Operating Procedures Will Be Revised
05000413/LER-1985-020, :on 850314,reactor Trip Occurred Due to Power Range High Flux Rate Signal.Caused by Loose Detector Cable Inside Power Range Cabinets.Work Request Initiated to Repair Loose Cable
05000327/LER-1986-028, :on 860702,discovered Failure to Comply W/Asme Section XI Accuracy & Range Requirements for Instruments Used for Pump Testing.Caused by Personnel Error.Instruments Calibr to Required Accuracy
05000395/LER-1987-002, :on 870225,roving Fire Watch Patrol Inadvertently Established in Room IB-412-04 in Lieu of Room IB-412-14.Caused by Personnel Error.Face to Face Communications Between Personnel Required
05000327/LER-1986-009-01, :on 860404,auxiliary Bldg Ventilation Isolation Occurred Due to Loss of Power to Radiation Monitor (RM)-90-101.Caused by Craftsman Contact W/Disconnect Switch. Switch Reclosed
05000249/LER-1986-003-08, :on 860403,power Lost to 4 Kv Emergency Bus 34-1 Resulting in Reactor Bldg Ventilation Sys Isolation. Caused by Personnel Leaving Relay Trip Check Open.Event Reviewed W/Responsible Individual
05000370/LER-1986-006-02, :on 860329,chemical & Vol Control Charging Pump 2A Racked in Svc W/O Emergency Power Supply,Resulting in No Operable Boration Flow Path.Caused by Personnel Error. Incident Will Be Reviewed During Staff Meeting
05000440/LER-1986-054, :on 860902,07,11,13,15 & 19,RCIC Isolations Occurred.Caused by Instrument Isolation Valve Failure & Impulse Line Slope Problems,Leak Detection Response Time & Personnel Error.Valves Repaired or Replaced
05000346/LER-1986-033, :on 860729,determined That Some Blowout Panels in Shield Bldg Wall Would No Longer Withstand Differential Pressure During Loca.Caused by Inadequate Technical Review of Panel Design Functions.Panel Revised
05000245/LER-1986-010-01, :on 860326,isolation Condenser Condensate Return Valve 1-IC-3 Failed to Open During Surveillance Testing.Caused by Motor Operator Torque Switch Trip. Operating Procedure Revised
05000270/LER-1986-003-05, :on 860602,core Flood Tank 2B Boron Concentration Fell Below Tech Spec Min of 1,828 Ppm.Cause Undetermined.Tank 2B Continuously Fed & Bled to Raise Boron Concentration
05000346/LER-1986-025, :on 860701,review of Tech Spec 3.3.3.8 Revealed Four Differences Between Installed Fire Detection Zones & Operability Requirements.Caused by Personnel Error.Fire Watch Established
05000317/LER-1998-003, :on 980113,damage Was Found on Stanchion & Restraining Steel of Unit 1 LPSI Sys Pipe Support Location on Common Discharge Line.Caused by LPSI Pump Discharge Check Valve Slam(S).Pipe Support Was Removed
05000414/LER-1986-021-01, :on 860530,main Feedwater Isolation Occurred During Testing of Auxiliary Safeguards Relays.Cause Undetermined.Isolation Signal Reset & Control Valves Realigned
05000413/LER-1986-027, :on 860519,automatic Nuclear Svc Water Sys Alignment to Standby Nuclear Svc Water Pond Actuated. Caused by Defective Procedures.Procedure Change 15 to Encls 13.12 & 13.14 of PT/2/A/4200/09A Begun
05000237/LER-1986-007-07, :on 860501,two Containment Atmosphere Monitoring Lines Did Not Meet NUREG-0661 Criteria.Caused by Lack of Design Document Control During Mod.Monthly Status Rept Will Be Mailed to Each Ae
05000413/LER-1986-053, :on 860927,nuclear Svc Water Sys (Nsws) Automatically Aligned to Standby Nuclear Svc Water Pond Due to auto-start Signal for Nsws Pumps.Caused by Personnel Error.Nsws Sys Realigned & Personnel Counseled
05000382/LER-1988-002, :on 880126,reactor Manually Tripped When Reactor Coolant Pump Upper Thrust Bearing Overheated.Caused by Clogged Lube Oil Strainer.Small Mesh Strainer Replaced W/Larger Mesh Strainer
05000220/LER-1986-008, :on 860422,reactor Bldg Emergency Ventilation Sys Initiated Due to Undervoltage Condition on Instrument & Control Bus 30.Caused by Loss of Backfeed from Plant Switchyard.Investigation Continuing
05000289/LER-1988-001-02, :on 880316,CRD Breaker Failed Undervoltage Trip Test.Caused by Undervoltage Trip Paddle Lodged Over Armature Disk.Breaker Replaced.Maint Procedures Will Be Revised to Provide Direction for Verifying Dimensions
05000298/LER-1988-011, :on 880418,Group 6 Isolation Occurred While Performing Maint on 24 Volt Dc Battery.Caused by Miscommunication of Clearance Order Requirements & Actual Work to Be Performed on Batteries.Bus Restored
05000369/LER-1986-004-01, :on 860129,cumulative Offsite Dose from Liquid & Gaseous Effluents Periodic Test Not Performed.Caused by Personnel Error.Program Implemented to Ensure That Staff Members Receive Weekly Periodic Test Schedule
05000348/LER-1988-010, :on 880411,determined That Individually Neither of Control Room Pressurization Units Able to Maintain Required Pressure of at Least 0.125 Inches Water Gauge. Caused by Open Penetrations
05000278/LER-1987-001-03, :on 880408,actuation of Primary Containment Isolation Sys Occurred During Switching of 4 Kv Emergency Bus Feed.Caused by Lack of Procedural Guidance & Training for Operators.Training Bulletin Issued
05000346/LER-1985-005-01, :on 851230,12 Boot Seal Seams Determined to Have Inadequate Overlap.Caused by Inadequate Procedure. Procedure MP 1700.29, Fabrication Installation of Flexible Pressure & Fire Seals Generated
05000366/LER-1988-009, :on 880321,local Leak Rate Test Missed Resulting in Condition Prohibited by Tech Specs.Caused by Personnel Error.Test Performed & Penetrations Declared Operable
05000338/LER-1988-013, :on 880319,turbine Trip/Reactor Trip Occurred. Caused by Electrohydraulic Fluid Control Sys Malfunction. Servo Control Valves for Four Governor Valves Replaced & Tested Satisfactorily
05000285/LER-1988-005-01, :on 880612,reactor Trip Occurred on Generated lo-lo Steam Generator Level Received from Steam Generator 32.Caused by Failure of Smoothing Orifice Relief Device in Westinghouse Main Turbine.Orifice Repaired
05000341/LER-1988-007, :on 880214,deenergized Radiation Monitor Caused Control Ctr HVAC to Shift to Recirculation Mode.Caused by Improper Review of Sys Functions Prior to Performing Work. Personnel Involved Counseled on Event
05000440/LER-1988-022, :on 880607,0226 & 0530,Tech Specs Violated When Operation Change Completed Prior to Meeting All Applicable Tech Specs Surveillance Requirements.Caused by Personnel Error.Licensed Operators Will Be Trained in Event
05000317/LER-1997-005, :on 970529,reactor Coolant Sys Leak Occurred. Caused by Failed Compression Fitting.Conducted Review of Compression Fitting Maint Performed on High Pressure Systems & Completed Insps of Compression Fittings
05000366/LER-1988-002, :on 880219,surveillance Requirements of Tech Specs Not Met.Caused by Personnel Error.Special Purpose Procedures Developed & Surveillances Performed or Scheduled
05000366/LER-1987-016-02, :on 871231,surveillance Not Performed within Time Limit.Caused by Personnel Error.Surveillance Performed, Verified & Schedule Modified.Personnel Counseled. W/88018 Ltr
05000269/LER-1986-003-02, :on 860208,discovered That Effluent Grab Sample from Chemical Treatment Pond 3 Missed.Caused by Personnel Oversight & Misentry Into Log Book.Personnel Counseled. Procedures Will Be Clarified
05000341/LER-1986-006, :on 860321,Div II Emergency Equipment Cooling Water & Emergency Equipment Svc Water Sys Automatically Started.Caused by Uncleared Undervoltage Signal on 4,160-volt Emergency Bus
05000333/LER-1986-007, :on 860323,Limitorque Valve Actuator Torque & Limit Switch Insulation Discovered Unqualified.Basis for Qualification Not Established in Applicable Rept.Actuators Replaced W/Actuators Qualified Per NUREG-0588
05000286/LER-1985-012-01, :on 851130,after Trip,Source Range Nuclear Instrumentation Channel 31 Failed to Reenergize When Reactor Neutron Flux Dropped Below Permissive Setpoint.Caused by Loose Wire Connection.Connection Repaired
05000423/LER-1985-001-01, :on 851209,during Cold Shutdown,Small Perforation Discovered in Fuel Oil Header Pressure Return Line Tubing of Emergency Diesel Generator A.Caused by Cyclic Vibration & Chafing Against Skid Frame
05000528/LER-1985-093, :on 851218,improper Valve Lineup on Radiation Monitor RU-141 Discovered.Caused by Radiation Protection Technician Error & Missing O-ring from Sample Holder Which Prevented Low Flow Alarm.Procedures Revised
05000245/LER-1985-027, :on 851121,loss of Normal Power Occurred While Trip Testing Breakers.Caused When Technician Used Incorrect Tripping Sequence,Causing Main Transformer to Divorce from Grid.Gas Turbine Failed to Respond
05000213/LER-1984-017, :on 841004,degradation of 15-conductor Interconnection Cable Discovered.Caused by Aging.Insp for Similar Problems in Other Equipment Concluded Problem Isolated Incident.Degraded Equipment Replaced
05000413/LER-1985-064, :on 851107,required Fire Watches for Two Fire Zones W/Inoperable Fire Detection Equipment & Fire Barriers Not Performed within Specified Time Limit.Caused by Personnel Error & Mgt Deficiency
05000413/LER-1985-062, :on 851104-05,continuous Fire Watch Not Conducted on Diesel Generator 1B While Low Pressure Cardox Fire Protection Sys Disabled.Caused by Miscommunication Between Security & Maint Personnel
05000366/LER-1997-003-02, :on 970328,excessive Leakage Identified on Secondary Bypass Valves Was Caused by Undersized Valve Operators & Inappropriate Valve & Operator Orientation. Re-routed Piping Containing Valves
05000270/LER-1986-001-03, :on 860131,reactor Tripped from 100% Power. Caused by Procedural Deficiency Resulting in Failure to Block Breaker Failure Initiate Relay to Power Circuit Breaker During Carrier Test.Contacts Replaced
05000237/LER-1985-040-03, :on 851021,during Review of Mar 1978 SER Re Plant Fire Protection Program,Discrepancies Concerning Mods Described in SER Discovered.Caused by Inadequate Documentation of Commitments in SER
05000323/LER-1985-016-01, :on 851126 & 1201,automatic Reactor Trips Occurred During 50% Load Rejection Startup Testing.Caused by Steam Dump Control Sys & Feedwater Control Sys Settings Inadequately Adjusted,Respectively
05000461/LER-1997-004, :on 970204,failed to Properly Implement TS SR 3.6.5.3.3 Due to Inadequate Procedure.Revised Surveillance Procedure to Verify Valves Closed
05000321/LER-1996-014, :on 961106,incorrect Circuit Breaker Setting Resulted in Inoperable Edg.Caused by Failure to Incorporate Design Info Into Appropriate Plant Single Line Electrical Drawing.Temporary Plant Mod Will Be Installed
05000348/LER-1996-006, :on 961008,Kaowool Fire Barrier Sys on Six Unit 1 Raceways Did Not Comply with Program Requirements. Caused by Personnel Error.Hourly Fire Watches Established & Will Remain Until Sys in Compliance
05000413/LER-1985-029, :on 850423,determined That End Stringer Clearance in Vital Instrumentation & Control Power Sys Exceeded Limits.Caused by Incorrect Mfg Installation Drawings.Styrofoam Spacers Installed
05000259/LER-1985-023-01, :on 850613,partial Containment Isolation Occurred When Temporary Jumper Slipped Off Relay Neutral During Replacement of Defective Relay.Dislodged Jumper Reconnected & Isolation Reset
05000370/LER-1985-010-02, :on 850502,vent Line Sight Glass Cracked & Valve Diaphragm Ruptured Due to Opening of Mislabeled Valve While Venting Upper Head Injection Piping.Caused by Administrative Error.Sight Glass & Valve Fixed
05000251/LER-1985-011-01, :on 850517,reactor Trip Occurred When off-site Power Lost Due to Multiple Faults on High Voltage Power Sys. Caused by Multiple Intense Brush Fires.Natural Circulation Cooling Established
05000370/LER-1985-015-01, :on 850517,upper Head Injection Accumulator Declared Inoperable Due to Missed Boron Concentration Verification.Caused by Personnel Oversight.Verification Performed.Event Will Be Reviewed W/Personnel
05000413/LER-1985-030, :on 850509,nuclear Svc Water Sys Automatically Aligned to Standby Nuclear Svc Water Pond & All Idle Sys Pumps Started Due to False lo-lo Level Signal in Sys Pumphouse Pit B.Caused by Loss of Voltage
05000325/LER-1990-013, :on 900725,determined That Cad/Containment Atmosphere Dilution Subsystem Design Did Not Meet FSAR Re Redundancy of Power Supply for Vaporizer Trains.Caused by Changing Regulatory Commitments.Sys Reviewed
05000328/LER-1985-006-03, :on 850406,air Control Valve for ERCW Valve 2-FCV-67-186 Found in Closed Position.Caused by Improper Back Plate Indications.Back Plates Will Be Modified
05000336/LER-1996-021-01, :on 960227,snubber Failure in Pressurizer Spray Line Occurred.Caused by Corrosion.Replaced Snubber Serial 12883 W/Identical Model PSA-1 Snubber
05000250/LER-1985-010, :on 850330,subcooling Margin Monitors Considered Inoperable Per Tech Specs & Plant Shutdown.Caused by Failure of RCS Temp Elements to Meet Environ Acceptance Criteria.Elements Will Be Replaced
05000416/LER-1984-056, :on 841219,RCIC Sys Containment Isolation Valve Closed on High Steam Low Signal.Caused by Spurious High Flow Signal Produced by Pressure Oscillations in Sensing Line. Pressure Equalized in Sensing Lines
05000293/LER-1985-004, :on 850215,reactor Shut Down Due to Small Leak in Socket Weld.Spool Piece & Weld Replaced
05000413/LER-1984-030-02, :on 841129,containment Penetration Leak Rate Test Performed Improperly.Caused by Penetration Piping Being Completely Drained.Procedures Revised
05000416/LER-1984-055, :on 841130,discrepancies Identified Between Design & Commitments to Reg Guide 1.63 Involving Overcurrent Protection of Containment Penetrations
05000370/LER-1984-030-01, :on 841126,following 841124 Reactor Trip, Jumpers on Two Lead/Lag Cards Found Not Installed.Caused by Deficient Vendor Drawings & Documents.Adequacy of Current Testing Procedures Checked
05000269/LER-1984-004-04, :on 841006,RCS Cooldown Rate Exceeded as Temp Decreased 57 F in 1/2 H.Caused by Personnel Error.Personnel Counseled Re Correct Interpretation of Appropriate Tech Spec
05000454/LER-1985-012, :on 850117,Tech Spec Surveillance for Steam Generator Blowdown Containment Isolation Valves Found Past Critical Date Re Valve 1SD005C.Caused by Testing of Improper Valve on 850108.Surveillance Program Modified
05000327/LER-1984-061, :on 840927,RCS Pressurizer Relief Tank Pressure Indicators Had Wrong Pressure Range.Cause Not Stated.Instrument Ranges Will Be Reviewed to Ensure Agreement W/Tech Specs
05000388/LER-1985-001, :on 850112,HPCI Turbine Failed to Trip During Hot Functional Test HF-252-011.Caused by Broken Stop Valve Actuator Shaft.Actuator Shaft Replaced
05000413/LER-1985-002, :on 841231,unit Entered Hot Shutdown W/Ice Condenser Lower Inlet Doors Blocked Closed.Incident Discovered on 850109.Caused by Personnel Error.Blocking Devices Removed & Training Sessions Held
05000334/LER-1984-011, :on 841012,eight Main Steam Safety Valve Lift Settings Found Outside Tech Spec Limits.Caused by Setpoint Drift.Valves Adjusted & Tested
05000260/LER-1984-008-04, :on 841129,IGSCC Indications Found in Recirculation Piping Reactor Water Cleanup Piping & Jet Pump Instrument Nozzles.Affected Welds Will Be Repaired Before Startup
05000259/LER-1985-006-02, :on 850304,during Performance of HPCI Sys Motor Operated Valve Operability Surveillance Instruction 4.5.E.1.c,HPCI Inverter Fuse Cleared.Caused by Blown Inverter Fuse.Fuse Replaced
05000316/LER-1985-004-01, :on 850125,RCS Loop 2 Cold Leg Temp Found Not Environmentally Qualified.On 850126,unit Trip Occurred. Caused by Unrelated Component Failure.Loop Replaced W/Qualified Spare
05000280/LER-1984-018, :on 840823,operator Discovered Air Hose Blocking Open Fire Door Between Equipment Space 1 & Cable Spreading Room.Caused by Misinterpretation of End of Walkdown Procedures.Hose Removed
05000414/LER-1995-006-02, :on 951215,missed TS Surveillance for Ac Offsite Power Sources.Caused by Personnel Error.Discussed Mgt Expectations for Attention to Detail W/Operator at Controls
05000285/LER-1995-006, :on 950824,improper Start of Number 1 DG Caused Rt.Caused by Inadequate Administrative Controls on Critical Parameter.Provided Addl Administrative Controls to Ensure That Governor Was Operated Correctly
05000327/LER-1995-015, :on 951101,ESF Actuation Occurred Due to Misinterpretation of Procedural Note of Determining Differential Proessure Across MSIV Prior to Opening Valve. Counseled Involved Personnel
05000315/LER-1984-007-01, :on 840522,detector Code Programming Error Discovered in Calculational Logic While Modifying Code. Procedure Change Made to Require Independent Line by Line Review of Coding
05000254/LER-1984-006-03, :on 840501,performance of Maint on Turbine Isolation Valves & MSIVs Resulted in Communication Via Main Steam Piping Between Reactor Bldg & Turbine Bldg.Caused by Procedural Inadequacy
05000311/LER-1984-010-01, :on 840423,during Startup Operations,Turbine Trip & Reactor Trip Occurred.Caused by high-high Level in Steam Generator 23.Feedwater Flow Nozzle Replaced & All Sys Performed as Designed
05000220/LER-1984-006, :on 840413,during Refueling Outage,Ak Breaker Feeding Power Tripped Open Due to Dirty Contacts,Causing Loss of Power to Powerboard & Other Sys.Full Scram Signal Resulted.Breaker Contacts Cleaned
05000220/LER-1984-010, :on 840608,reactor Protection Sys Channel 4 Power Supply Bus Experienced Momentary Power Loss Causing Condenser vacuum-MSIV Closure Scram Bypass Relays to Deenergize
05000369/LER-1984-020, :on 840606,reactor Tripped When Spurious Undervoltage Relay Actuation Deenergized One Reactor Coolant Pump.Caused by Component Malfunction.Further Testing Will Be Conducted to Determine Failure Mechanism
05000289/LER-1991-004, :on 911008,irradiated Fuel to Test Hoist Interlocks W/O Full Containment Isolation.Caused by Staff Error & Procedural Inadequacy.All Licensed Operators to Receive Addl Training & Procedures Revised
05000333/LER-1984-006, :on 840213,reactor Water Indicating Switch Found Out of Tech Spec Limits.Caused by Excessive Internal Mechanical Friction.Surveillance of Equipment Will Be Performed & Manufacturer Contacted
05000318/LER-1984-001-01, :on 831005,1220 & 840203,ECCS Pump Room Ventilation Sys Exhaust Fan Discharge Damper 21 Would Not Open.Caused by Air Supply to Exhaust Fan Discharge Damper Isolated.Air Restored & Sys Returned to Svc
05000364/LER-1995-005, :on 950601,loss of electro-hydraulic Fluid Resulted in Manual Rts.Repaired & Selected Welds on Eh Sys of 2A & 2B SGFP
05000298/LER-1984-004, :on 840405,operator Observed Increase in Turbine Speed & Pump Discharge Pressure W/Zero Output.Caused by Defective Ramp Generator & Signal Converter Box.Generator Replaced.Sys Tested Satisfactorily
05000281/LER-1984-004, :on 840315,67 of 267 Snubbers Failed to Meet Acceptance Criteria Stipulated in Snubber Administrative Procedures.Snubber Program Being Revised to Provide Better Controls on Maint & Tracking of Snubbers
05000369/LER-1984-008-01, :on 840112,during FSAR Review,Nrc Noted Several Model Changes to Westinghouse Marvel Code Used to Calculate Mass & Energy Release for Main Steam Line Breaks. Cause Not Stated.Analysis Performed
05000458/LER-1995-005-02, :on 950627,HPCS Pump Breaker Tripped During Surveillance Testing.Cause of Failure Not Identified.Breaker Internals,Prop Springs & Closing Latch Spring Inspected.W/
05000331/LER-1984-002, :on 840103,HPCI Inboard Steam Supply Isolation Valve Declared Inoperable.Caused by Technician Mistakenly Installing Jumper Across Relay Contact.Jumper Removed Allowing Valve to Open & Return to Svc
05000445/LER-1990-009, :on 900421,reactor Trip Occurred Due to Accidental Bumping of Source Range Reactor Trip Reset/Block Previously Bypassed for Power Operation.Order Issued Suspending Cleaning of Control Boards
05000245/LER-1994-015, :on 940410,during Surveillance Test,Inadvertent Decrease of RPV Water Level Occurred.Caused by Failure to Recognize Interactions.Corrective Action:Restored RPV Water Level & Isolated Leakage
05000285/LER-1991-002, :on 901209,ventilation Isolation Actuation Signal Generated by High Alarm on Process Radiation Monitor RM-062.Caused by Accumulation of Noncondensible Gases in Sample Piping.Valve Packing Leak Repaired
05000328/LER-1989-014-03, :on 891110 & 11,containment Ventilation Isolations Occurred.Caused by Personnel Error.Procedure to Be Issued for Use While Venting Sys Known or Suspected to Contain Radioactive Noble Gases
05000400/LER-1988-002-01, :on 880119,vent Stack wide-range Gas Monitor RM 1WV-3547-1 Declared Inoperable Under Tech Spec 3.3.3.11, Due to Missed Maint Surveillance Test on 871227.Caused by Procedural Deficiency.Procedure Revised
05000400/LER-1987-052, :on 870831,mechanic & Health Physics Technician Exiting Containment Through Personnel Access Hatch When One of Door o-ring Seals Fell Out of Groove.Caused by Personnel Error.Work Request Issued to Repair Door
05000425/LER-1998-004-02, :on 980419,defeat of Turbine Trip Function Led to Improper Mode Entry.Caused by Inadequate Administrative Controls of Work Process.Controls to Prevent Recurrence Are Being Instituted
05000318/LER-1989-003, :on 890307,plant Shutdown Due to Air Leak on Feedwater Regulating Valve (Frv).Caused by Failure to Identify Need to Perform Adequate Preventive Maint on Positioner.Frv Controller Placed in Manual
05000260/LER-1987-003-03, :on 870503,analysis of Water Sample from Reactor Vessel Found Ph Outside of Tech Spec (TS) Limits.On 870505,conductivity Increased Beyond TS Limits.Rwcu Demineralizers Placed in Svc
05000339/LER-1986-006, :on 860416,discovered Specific Gravities of Battery Cells on 3 of 4 Dc Busses Below Min.Caused by Failure to Correct Specific Gravities to Full Electrolyte Level.Administrative Procedure Revised
05000250/LER-1986-037, :on 861212,min Redundancy Requirements Not Met When Power Range Neutron Flux Detector N-41 Taken Out of Svc.Caused by Failure to Place Overpower Reactor Trip Signal in Tripped Condition.Procedure Revised
05000315/LER-1986-004, :on 860228,reversing Starters Improperly Arranged in Motor Control Ctr & Fault in Control Transformer Could Result in Loss of Ctr.Design Change Implemented & Problem Will Be Resolved During Outage
05000237/LER-1986-018-04, :on 860713,reactor Coolant Sample Not Taken During Reactor Startup.Caused by Miscommunication within Radiation Chemistry Dept.Event Discussed W/Involved Personnel
05000423/LER-1988-013, :on 880328,incomplete Installation to Circuits in Hydrogen Recombiner Sys Determined.Caused by Circuits Not Being Installed in Accordance W/Last Design Document.Work Completed as Described in Design Document
05000366/LER-1986-007, :on 860213,HPCI Steam Supply Outboard Isolation Valve 2E41-F002 Isolated Due to Unplanned Isolation Signal from Differential Pressure Transmitter.Caused by Defective Procedure.New Procedure Written
05000413/LER-1985-007, :on 850122,diesel Generators 1A & 1B Started on Blackout Signal.During Troubleshooting on Circuit Breaker 1B,Zone B Lockout Initiated,Causing Trip of 6,900-volt Switchgear.Caused by Design Deficiency
05000364/LER-1990-005-01, :on 901216,total of 574 Tubes Previously in Svc Found to Be Defective Which Requires Insp Results to Be Classified as Category C-3
05000412/LER-1987-011-01, :on 870730,inadvertent Safety Injection Occurred Due to Low Steam Line Pressure.Caused by Personnel Error.Test Engineer Reassigned & Incident Will Be Reviewed at Safety Meetings