05000029/LER-1985-010, Forwards LER 85-010-00 Re Inadvertent Reactor Scram During Maint Activity
B16740, Reissues LERs 97-031-00 & 97-014-02 Which Includes Rept Dates That Were Inadvertently Ommited in Previous Rept
05000328/LER-1988-019-02, :on 880407,discovered That Two ECCS Pumps to Be Inoperable,Resulting in Inadvertent Entry Into Tech Spec 3.0.3.Caused by Inadequate Work Control.Plant Procedure for Work Control Revised
05000277/LER-1989-011, :on 890424,scram Discharge Vol Drain & Vent Valve Stroking Surveillance Test Not Performed.Caused by Procedural Deficiency & Scheduling Error.Surveillance Test Completed Satisfactorily on 890429
05000331/LER-1989-006, :on 890224,isolation of RCIC & on 890302, Isolation of HPCI Occurred.Caused by Problems in Electrical Path from Thermocouples Monitoring Area Temp.Retermination of Broken Thermocouple Wire Before Break
05000260/LER-1989-006-02, :on 890331,reactor Protection Sys Deenergized, Resulting in ESF Actuations & Standby Gas Treatment,Control Room Emergency Ventilation & Refuel Zone Isolations.Caused by Personnel Standing on Breaker Cabinet
05000318/LER-1989-009-01, :on 890522,fire Damper Found in Closed Position by Fire Protection Design Engineer.Caused by Failure of Damper Fusible Link.Link Replaced,Damper Opened & Damper Insp Procedure Improved & Clarified
05000328/LER-1989-005-01, :on 890415,16 & 19,three Unit 2 Reactor Trips Occurred Due to Lo Lo Steam Generator Level During Startup. Cause for 890419 Trip Was Operating Loops Bypass Valves in Manual
05000341/LER-1989-014, :on 890603 & 18,discovered That Both Channels Bypass/Unbypass Functions Were Slightly Above Limits Allowed in Tech Specs.Caused by Emphasis on Checking Bypass Function of Bistable.Channels Properly Calibrated
05000277/LER-1988-029, :on 881110,inadequate Sealing of ECCS Pump Rooms Results in Plant Being Out of Design Basis.Caused by Lack of Clear Assignment of Penetrations to Mechanical or Civil Disciplines of Engineer Organization
05000461/LER-1989-015, :on 890311,surveillance Review Group Noted That Section 8.4 Not Been Performed within Max Time Interval Permitted by Tech Spec 4.0.2.Caused by Personnel Error. Individual Counseled on Failure to Use Ref
05000327/LER-1989-007-01, :on 890319,train a Control Room Isolation (Cri) Occurred.Caused by Personnel Error.Facility Assistance Shift Operations Supervisor Suspended Maint Activity on Smoke Detectors & Verified Train a Cri for Radiation
05000282/LER-1987-015-01, :on 870727,automatic Start of Diesel Generator & Other Equipment Actuations Occurred.Caused by Severe Weather.Plant Restored to Previous Condition
05000341/LER-1987-036, :on 870802,improper Valve Line Up During Fill & Vent Operation of RHR Caused Reactor Water to Divert from Reactor Vessel to Suppression Pool Causing Reactor Scram to Occur.Caused by Operator Error
05000259/LER-1987-013-01, :on 870712,standby Gas Treatment Sys Trains A,B & C & Control Room Emergency Ventilation Sys Trains a & B Actuated & Refuel Zone Isolation Occurred.Caused by Setpoint of Detector Lower than Vendor Recommendation
05000318/LER-1998-004-01, :on 980723,manual Plant Trip Occurred Due to Moisture Separator Reheater Vent Line Rupture.Caused by Flow Accelerated Corrosion.Replaced Ruptured Pipe & Completed Insp of Other Small Bore high-energy Piping
05000338/LER-1987-023-01, :on 871124,Kaman Process Vent Normal Range Radiation monitor,RI-GW-178-1,declared Inoperable.Caused by Loose Connection Between Central Processing Unit Card & Sys. Central Processing Unit Card Replaced
05000259/LER-1987-024-01, :on 870930,unplanned RWCU Isolation Occurred. Caused by Degraded Electrical Connections on Temp Switch. Isolation Reset & Sys Returned to Svc.Connections on Temp Switch Repaired
05000413/LER-1987-036, :on 860830,incorrect Alignment Performed Rendering Nuclear Svc Water (Rn) Train a Inoperable Re Unit 2 Power Operation.Caused by Design Deficiency Due to Incorrect Identification of Rn Alignment
05000259/LER-1989-002-02, :on 890208,buried Raw Cooling Water Discharge Piping Between Reactor Bldgs & Circulating Water Discharge Conduit Not Seismically Qualified.Caused by Design Error. Corrective Action Evaluated & Implemented
05000293/LER-1989-004, :on 890127,discovered Two Primary Containment Air Operated Valves Inoperable Resulting in Unit Shutdown. Caused by Pressure Drop Rate of Stored Air Supply for Valves.New Tubing Installed
05000382/LER-1987-023, :on 870813,invalid Grab Samples of Condenser Vacuum Pump Effluent Gas Resulted Due to Condensation from Pump Steam.Caused by Loop Seal Failure.New Method for Sampling Devised
05000346/LER-1997-002-01, :on 970122,identified Potential Overpressurization of Penetrations During Accident Conditions.Installed Mod to Protect Component Cooling Water Supply from Overpressurization Concerns on 970504
05000366/LER-1998-002-02, :on 980318,assembly Error Led to Malfunctioning Governor Causing EDG Inoperability.Caused by Sticking Shutdown Solenoid on DG Governor.Established Periodic Replacement Schedule for Solenoid
05000454/LER-1997-015-03, :on 970813,containment Penetration Test,Vent & Drain Valves Were Not Surveilled within 31 Days.Caused by Difference in Interpretation of Regulations.Surveillance Applied to All Valves
05000259/LER-1997-003-04, :on 970812,potential for Containment Pressure to Exceed Design During Purging or Inerting If LOCA Occurred Due to Unanalyzed Suppression Pool Bypass Path Was Noted. Caused by Design Error.Revised Sys Operating Instructions
05000327/LER-1986-045, :on 861002,short Occurred in Remote Control Power Branch Circuit Resulting in Blown MIS-5 Fuse in Feeder Circuit C42.Caused by Deenergized Wire Touching Energized Part of Circuit During Maint
05000220/LER-1986-030, :on 860916,reactor Bldg Ventilation Radiation Monitor 11 Tripped on Loss of Power,Resulting in Loss of Reactor Protection Sys Bus.Work Request Generated
05000370/LER-1986-020-02, :on 861118,generator Loss of Load Transient Occurred Followed by Main Feedwater Pump 2B Tripping on High Discharge Pressure Signal.Caused by Relay Fault.Operators Realigned Pump 2A to Feedwater Header
05000315/LER-1986-024-01, :on 861111,w/reactor at 90% Power,Esf Ventilation Fans Discovered Inoperable for Approx 18 Minutes.Caused by Damper Misalignment & Failure to Rept Error.Position Indicators Evaluated
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
05000348/LER-1987-008, :on 870504,fire Watch Discovered Not Posted as Required by Tech Spec 3.7.11.2 & Fire Door Left W/O Being Properly Closed.Caused by Personnel Error.Door Closed Immediately.Warehouseman Counseled
05000369/LER-1986-014-03, :on 860818,ESF Train B Safety Injection Signal Actuated from Pressurizer Safety Injection Low Pressurizer Pressure Signal.Caused by Defective Procedure.Procedure Change Implemented
05000348/LER-1986-014, :on 860801,both Trains of Charging Pumps Inoperable.Caused by Clogged Gear Oil Coolers.Svc Water Task Force Established to Investigate Problem
05000414/LER-1986-045-01, :on 861011,turbine-driven Auxiliary Feedwater Pump Found to Be Inoperable from Standby Shutdown Facility. Caused by Incorrectly Installed Solenoid Valve Due to Design Deficiency.Valve Retubed
05000414/LER-1986-044-01, :on 861021,two Containment Gas Monitor Containment Isolation Valves Found Inoperable.Caused by Equipment Failure.Valves MISV5230 & MISV5232 Opened. Sample Flow Annunciator Repaired
05000249/LER-1986-002-01, :on 860117,loss of Power to Radiation Monitors Occurred,Initiating Standby Gas Treatment Sys & Tripping Reactor Bldg Ventilation Sys.Caused by Procedural Inadequacy.Procedures Will Be Changed
05000220/LER-1986-031, :on 861014,reactor Bldg Emergency Ventilation & one-half Scram Initiated.Caused by Faulty Potentiometers in Voltage Regulator of MG Set 172.Voltage Regulator replaced.One-half Scram Reset
05000259/LER-1986-022-01, :on 860703,potential Safety Concern Identified During Design Review Re nonsafety-grade Air Solenoid Operators on Testable Check Valves That Could Fail.Air Supply to Solenoids Removed During Operation
05000336/LER-1986-022-01, :on 861223,reactor Tripped Due to Low Water Level in Steam Generator 1.Caused by Improperly Installed Bus Voltage Potential Transformer Drawer.Drawer & Cover Realigned & Reinstalled Squarely W/Bolts
05000370/LER-1986-020, :on 861118,main Generator Loss of Load Transient Occurred Followed by Main Feedwater Pump 2B Tripping on High Discharge Pressure Signal.Caused by Excessive Moisture in Isolated Phase Bus
05000270/LER-1986-005-05, :on 860723,reactor Tripped on High Steam Generator Level.Caused by Failure of RCS Flow Transmitter 2A.Work Request to Repair Transmitter Initiated & Unit Stabilized in Hot Shutdown Condition
05000369/LER-1986-013-02, :on 860626,discovered Loose Fuel Pellets from Fuel Assembly D-03 on Reactor Core Baffle Plate Near Core Location P-3.Caused by Baffle Jetting.Assembly Removed from Core & Core Redesigned
05000251/LER-1987-004-01, :on 870205,intake Cooling Water Pumps 4C & 4B Declared Out of Svc.Caused by Repairs to Discharge Check Valve Air Cylinder & Failure of Pump Shaft Coupling.Repairs Completed & Couplings Replaced
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
05000325/LER-1986-033, :on 861104,during Development of PRA Model, Diesel Generator Bldg Ventilation Design Deficiency Identified.Caused by Failed Close Design of Supply Dampers. Supply Plenum Damper Linkages Wired Open
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
05000382/LER-1999-013, :on 990825,exceeding TS Limits for RCS Cooldown Rate Was Discovered.Caused by Inadequate Content & Inadequate Implementation of TS Requirements.Page 2 of 2 in Attachment 2 of Incoming Submittal Not Included
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
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
05000220/LER-1986-017, :on 860615,reactor Scram Occurred.Caused by Reactor Low Water Level Setpoint Being Reached During Operator Surveillance Test for Automatic Startup of HPCI Mode of Feedwater Sys
05000333/LER-1997-009-01, :on 970905,discovered Radwaste Bldg Exhaust Monitor Instrument Channel Calibr Test,Required Ts.Caused by Personnel Error.Comprehensive Root Cause Analysis Completed to Review & Identified Human Performance Considerations
05000220/LER-1986-015, :on 860530,reactor Scram Occurred,Initiating Reactor Bldg Emergency Ventilation.Caused by Lifted Neutral Leg of Output Protective Relaying Circuit.Lifted Lead Replaced & Reactor Scram Reset
05000414/LER-1986-017-01, :on 860429 & 0521,auxiliary Feedwater Pump Turbine & motor-driven Pump Failed to Produce Required Discharge.Caused by Fouled Pressure Cage Assemblies. Assemblies Cleaned
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
05000280/LER-1986-029, :on 860929,svc Water to Charging Pump Svc Water Subsystem Lost.Caused by Leak on Blowdown Line for in-line Strainer.Line Repaired
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
05000382/LER-1986-021, :on 860924,hourly Firewatch Tour Not Performed in Shutdown Cooling HX Room B.Caused by Personnel Error.Post Order for Firewatch Patrol Revised
05000528/LER-1986-053, :on 860911,reactor Tripped on Low Steam Generator Pressure.Caused by Procedural Inadequacy Re Use of Circuit Card Extender Board During Maint.Notice Distributed & Procedures Revised
05000483/LER-1986-034, :on 860908,pre-action Sprinkler Sys Protecting Cable Trays of Auxiliary Bldg Inoperable W/O Continuous Fire Watch.Caused by Personnel Error.Design & Annunciator Response Procedure Evaluated
05000285/LER-1997-011-01, :on 970819,violation of Tech Specs Due to Inoperability of Radiation Monitor Occurred.Caused by Lack of Depth in Evaluation/Review by Station Personnel. Procedures Will Be Revised
05000382/LER-1987-001, :on 870115,valve CC-710 Found Leaking Excessively & Valve Seat & Retaining Ring Missing.Caused by Error of Maint & QC Personnel of Installation Contractor.All Valves Listed in Table 3.6-1 Tested
05000483/LER-1986-029, :on 860825,reactor Manually Tripped Due to Rod Control Sys Failure Following Turbine Runback.Caused by Slave Cycler Control Card Failure.Card Replaced & Cooling to Rod Control Cabinets Increased
05000483/LER-1986-028, :on 860818,high Radiation Area Door Not Locked Per Tech Spec 6.12.2.Caused by Damaged Lock Mechanism.Latch Replaced,Other Locked Entrances Inspected & Plant Personnel Instructed in Operation of Locks
05000528/LER-1986-045-01, :on 860815,automatic Actuation of Reactor Protection Sys Initiated Automatic Reactor Trip Due to Manual Generator/Turbine Trip.Caused by Malfunction of nonsafety-related Steam Bypass Control Valves
05000280/LER-1986-024, :on 860813 & 14,at 100% Power,Control Room Chillers Failed to Operate.Caused by Clogged Chillers Due to Unfiltered River Water Flowing Through Tubes.Chillers Unclogged & Strainer Returned to Svc
05000382/LER-1986-017, :on 860811,chemistry Technicians Failed to Sample Proper Gas Decay Tank.Caused by Operations Personnel Realigning Inservice Tanks W/O Informing Chemistry Technicians.Procedure Revised
05000382/LER-1987-001-01, :on 870330,gaseous Waste Mgt Effluent Radiation Monitor Alarm/Trip Setpoint Set Factor of 10 Too High Since Plant Startup.Caused by Personnel Error.Rms,Its Database & Data Base Change Methodology Under Review
05000382/LER-1986-016, :on 860804 & 21,boron Concentration for Safety Injection Tanks Fell Below Tech Spec Limit.Caused by Insufficient Procedural Requirements.Procedure Change Will Be Made to Prevent Recurrence
05000440/LER-1986-093, :on 861229,plant Placed Into Operational Condition 1 When Containment Vacuum Breaker Opened.Caused by Personnel Error.Individuals Counseled Re Responsibility to Initiate Limiting Condition for Operation
05000410/LER-1986-020-01, :on 861218,Div 1 ECCS Initiation Experienced Due to Spurious High Drywell Pressure Signal.Caused by Electricians Replacing Relay.Electrical Maint Training Initiated
05000341/LER-1986-045, :on 861117,during Sys Restoration,Incorrect Valving Sequence Caused Damage to Test Return Line for Condensate Storage & Return Tanks.On 861201,water Collected in Cable Vaults Released to Outflow Canal
05000410/LER-1986-018-01, :on 861216,while Testing Off Normal Status Sys Isolators,Electrician Placed Jumpers from 120-volt Dc Source to 120-volt Ac Line Source,Resulting in Blown Fuse.Caused by Test Engineer Error.Engineer Disciplined
05000341/LER-1986-017, :on 860624,discovered That Emergency Equipment Cooling Water Sys Capacity Inadequate to Remove Drywell Cooler Heat Loads During Small Break Inside Drywell W/O Degrading Performance.Design Change Issued
05000220/LER-1986-034, :on 861206,loss of Stack Gas Monitoring Experienced When Radioactive Gaseous Effluent Monitoring Sys Shut Down Sys Sample Supply Pump.Possibly Caused by Problem in Stack Monitoring Sys Software
05000409/LER-1986-018, :on 860622,reactor Scrammed Due to Relay Failure & Line Separation at Reactor Water Level Transmitter.Water Level Transmitters Recalibr
05000382/LER-1986-012, :on 860625,discovered That Surveillance for Fire Doors D221 & D222 Not Performed on Daily Basis.Caused by Lack of Interdepartmental Communication.Procedure OP-903-001 Revised
05000269/LER-1986-015-04, :on 861120,Keowee Hydro Relay 94 T/K Actuated During Mod Work,Causing Lockout of Transformer,Trip of Circuit Breakers & Loss of Overhead Emergency Power.Caused by Mechanical Vibration Due to Drilling
05000249/LER-1986-008-08, :on 860618,Group II Primary Containment Isolation Received,Causing Isolation of Reactor Bldg Ventilation & Start of Standby Gas Treatment Sys.Caused by Personnel Error.Personnel Cautioned Re Maint
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
05000370/LER-1986-012-03, :on 860722,reactor Tripped on High Pressurizer Pressure.Caused by Primary to Secondary Sys Mismatch Due to Failed Counter Card within Digital electro-hydraulic Control Sys.Card Replaced
05000328/LER-1986-001-04, :on 860525,discovered All Valves Located in Boron Injection Flow Path Not Verified in Correct Positions. Caused by Incorrect Statement in Surveillance Instruction. Surveillances Reviewed & Found Acceptable
05000346/LER-1987-006, :on 870313,reactor Trip Occurred.Caused by Closure of Main Feedwater Stop Valve for Steam Generator 2 After Const Worker Bumped Local Control Switch.Cover Installed Over Switch for Valve
05000293/LER-1988-024-01, :on 881017,Group 1 Isolation Signal Due to High Water Level in Reactor Vessel Occurred.Caused by Disassociation of Pin from Feedback Cam Linkage of Valve Positioner for Valve.Linkage Secured
05000409/LER-1987-003, :on 870311,containment Bldg Gas Monitor Alarmed Causing Containment Bldg Ventilation Dampers & Vent Header Valve to Close.Caused by Dirty Contacts on Monitor Ratemeter Range Switch.Isolation Signal Reset
05000324/LER-1999-002-02, :on 990329,reactor Tripped.Caused by Failed Electrical Connections on Vibration Detector for Number 9 Main Turbine Bearing.Vibration Detectors for Main Turbine Number 9 Bearing Replaced.With
05000334/LER-1999-004-01, :on 990317,inadequate pre-fire Plan Procedure Guidance Resulted in Potential Damage to Charging/Hhsi Pumps.Caused by Inadequate Consideration of Required Operator Actions.Procedure Revised.With
05000414/LER-1986-005-03, :on 860417,discovered Leak Rate Retest Not Performed on Containment Isolation Valve Following Maint. Caused by Personnel Error.Personnel Counseled
05000409/LER-1986-014, :on 860418,determined That During Discharge of 3,000 Gallon Waste Tank,Water from 4,500 Gallon Waste Tank Also Pumped.Caused by Open Suction Valve Leading to Operating Waste Transfer Pump.Valve Closed
05000369/LER-1987-004-03, :on 870218,reactor Tripped Due to Low RCS Flow. Caused by Failed Surge Capacitor Resulting in Reactor Coolant Pump Motor 1C Tripping on Ground Fault.Surge Capacitor Replaced
05000413/LER-1985-059, :on 851010-12,reactor Shut Down Due to RCS Leakage in Excess of 1 Gpm.Caused by Leaking Compression Tube Fitting on Flow Transmitter.Fitting Tightened
05000370/LER-1987-004-02, :on 870217,discovered That Analog Channel Operational Test on Containment Hydrogen Analyzer 2B Not Performed at Required Intervals.Caused by Personnel Error. Periodic Test Scheduling Procedures Revised
05000409/LER-1986-021, :on 860716,reactor Scram Occurred.Caused by Static Inverter 1A Transferring Alternate Source & Momentarily Deengergizing Scram Trains.Inverter Will Be Replaced Prior to Plant Startup
05000409/LER-1986-022, :on 860718,during Reactor Shutdown,Two Small Cracks Leaking Water on Decay Heat Suction Line Discovered. Cause Unknown.Pipe Section Removed & Replaced.Cracks Will Be Examined to Determine Cause
05000382/LER-1986-015, :on 860714,loss of Shutdown Cooling Occurred. Caused by Simultaneous Use of Methods of Draining RCS & Inaccurate Level Indication.Procedures OP-1-003 & OP-901-046 Revised
05000369/LER-1985-027-01, :on 850911,pressurizer Heater Group 1B Inoperable While Diesel Generator 1A Inoperable.Caused by Personnel Error.Generator Returned to Operable.Rept Will Be Reviewed W/Personnel
05000443/LER-1987-005, :on 870214,panel Mounted Indicators Found Improperly Secured.Problems Occurred During Installation. Affected Indicators Properly Secured
05000382/LER-1999-002-03, :on 990225,discovered RCS Pressure Boundary Leakage on Two Inconel 600 Instrument Nozzles.Caused by Axial Cracks Near HAZ of Nozzle Partial Penetration Welds Resulting from Pwscc.Leaking Nozzles Have Been Repaired
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
05000413/LER-1985-021, :on 850313,during Performance of Turbine Driven Auxiliary Feedwater Pump Operability Test,Discovered CA Pump 1 Had Failed 850309 Operability Test.Caused by Personnel Error.Test Completed
05000327/LER-1986-008, :860401,monthly Channel Check for Steam Generator narrow-range Level Shutdown Instrumentation Not Properly Performed on SI-3 Logs.Caused by SI-3 Incorrectly Written for wide-range Level Instruments
05000409/LER-1986-010, :on 860404,containment Ventilation Valves Closed When Containment Bldg Gas Monitor Failed High.Cause Not Found.Troubleshooting Performed on Instrument Drawer Detected No Problems
05000327/LER-1986-042, :on 860908,two Tech Spec Surveillance Requirements Not Performed.Caused by Inadequate Procedures. SI-129 Revised to Require Less than 1,700 Psi & Westinghouse cross-calibr Procedure Implemented
05000327/LER-1986-011-01, :on 860328,review of Tech Spec Surveillance Noted That Setpoint for Containment Sump Level in Error as Listed in Limiting Condition for Operation 3.3.2.1.Caused by Error in Instrument Mounting Drawing
05000440/LER-1986-057, :on 860903,containment Isolation Valves Not Deactivated in Closed Position.Caused by Failure of Nonconformance Rept Program to Require Routing of Environ Qualification Deficiencies to Control Room.Program Revised
05000409/LER-1986-008, :on 860403,spurious Low Reactor Water Level Signal Received.Caused by Mistakenly Deenergized Electric Distribution Panel During Troubleshooting of Instrumentation Problem.Sys Restored to Normal
05000315/LER-1986-019-01, :on 860731,discovered That During Calibr of Waste Gas Hydrogen Analyzer,Improper Gas Mixture Used to Check Accuracy of Analyzer Following 860703 Calibr.Caused by Personnel Error.Calibr of Analyzer Performed
05000306/LER-1986-003-02, :on 860728,unit Tripped & All Train a Safeguards Equipment Actuated During Check of Test Lights on Safeguards Test Panel.Caused by Mistakenly Resetting Train a Safety Injection
05000312/LER-1986-018, :on 860717,determined That Control Room Did Not Implement Compensatory Fire Protection Measures When Smoke Detectors Disabled for Welding Operations.Caused by Communication Problems.Memo Issued
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
05000413/LER-1986-018, :on 860324,both Trains of Auxiliary Feedwater Sys Inoperable for Over 6 H.Caused by Personnel Error, Resulting in Removal of Train B from Svc While Train a Inoperable
05000395/LER-1998-002, :on 980109,electrical Govenor (EG-A) Failed on a Edg.Caused by Inadequate post-refurbishment Bench Testing by Vendor.Vendor,Engine Sys,Inc Was Notified. Repaired & Tested EG-A,per 10CFR21
05000454/LER-1997-022-03, :on 971114,determined That Ssps Logic Testing Had Not Been Performed.Caused by Inadequate Testing Design. Added New Testing Criteria to Ssps bi-monthly Surveillance Procedures & Successfully Performed Testing
05000413/LER-1986-028, :on 860606,unidentified RCS Leakage Exceeded Tech Spec Limit of 1 Gpm.Caused by Seal 2 Becoming Unseated. Reactor Coolant Drain Tank Level Transmitter Recalibr & Seal 2 Reseated
05000338/LER-1986-010-01, :on 860603,diesel-driven Fire Pump Determined Inoperable During Performance of Weekly Surveillance Test. Caused by Failed Starter Motor.Replacement Starter Motor Installed
05000317/LER-1998-002, :on 980107,fire Hose Station & Room Sprinkler Sys Were Noted out-of-service.Caused by Operating Mislabeled Valve.Correct Tagout Boundary Was Established & Verified by Addl Complete Walkdown of Tagout
05000220/LER-1986-014, :on 860603,reactor Scram Occurred During Surveillance Test.Caused by Instantaneous Inlet of Water in Transmitter RE-16B.Surveillance Test Will Be Revised & Technicians Cautioned
05000336/LER-1986-003-01, :on 860516,evaluation of Fire Dampers in Response to IE Info Notice 83-69 Defined 20 Fire Dampers Improperly Installed or Rated for Fire Zones.Fire Patrols Established.Fire Dampers Will Be Changed
05000382/LER-1997-025, :on 971017,gag for Valve CC-835B Was Partially Engaged Restricting Valve to Approx 80% Open.Caused by Inadequate Work Instructions.Gag Was Completely Disengaged on Valve CC-835B
05000282/LER-1997-012-01, :on 971009,chemical & Volume Control Sys Malfunction,Occurred.Caused by Failure to Recognize Shutdown Margin Requirements in Usar.Procedures Modified to Maintain Increased Shutdown Margin
05000333/LER-1997-012-01, :on 971214,drywell Personnel Airlock Outer Door Seals Local Leak Rate Test Was Not Properly Performed.Caused by Inattention to Detail on Part of Mechanic Who Installed Label.Removed Incorrect Label
05000354/LER-1997-033, :on 971210,failure to Perform Secondary Containment Isolation Actuation Instrumention Channel Checks,Was Noted.Caused by Personnel Error.Personnel Involved Was Held Accountable
05000455/LER-1997-003-08, :on 971010,reactor Trip Occurred,Due to age-related Failures of Redundant Power Supplies That Went Undetected by Alarm Sys.Modification to Power Supply Failure Alarm Will Be Submitted to TRC for Review
05000416/LER-1997-006-02, :on 971121,release of Contaminated Liquid Outside of Controlled Access Area Was Noted.Caused by Lack of Administrative Control of Hydrolazing Inside Controlled Access Area.Secured & Cleaned Spill Area
05000414/LER-1986-002-05, :on 860413,containment Air Release & Addition Sys Release Terminated by Actuation of High Radiation Alarm. Caused by Generic Electrical Noise from Vacuum Switches. Alarm Reset.Grab Sample Taken
05000440/LER-1986-065, :on 860930,control Rod Movements Performed While Rod 30-27 Bypassed in Rod Action Control Sys W/O Being Electrically or Hydraulically Disarmed,Violating Tech Specs. Caused by Personnel Error.Training Provided
05000413/LER-1986-052, :on 860923,hourly Fire Watches Missed for Floor Hatches to Seal Water Injection 1A & 1B Filters.Caused by Personnel Error.Required Hourly Fire Watches Subsequently Performed & Incident Discussed W/Crew
05000260/LER-1986-013-02, :on 860927,unplanned ESF Actuations Occurred Due to Failed Relay in Refueling Zone Vent Exhaust Radiation Trip Logic.Caused by Burned Coil in GE Model CR120A Relay. Relay Replaced
05000348/LER-1999-002-02, :on 990527,Unit 1 Reactor Trip Occurred Following Loss of 1A SG Feedwater Pump.Caused by Personnel Error.Unit Was Stabilized in Hot Standby.With
05000409/LER-1988-002, :on 880129,temporary Absence of Duty Shift Supervisor from Shift.Scheduled Shift Supervisor Realized Absence & Assumed Duty Himself.Cause Unstated.Proper Shift Turnover Conducted
05000458/LER-1988-002, :on 880110,full Scram Inadvertently Initiated Via Alternate Rod Insertion Trip Sys.Caused by Personnel Error Due to Misleading Surveillance Test Procedure Wording. Procedure Revised & Rerun
05000382/LER-1988-012, :on 880526,steam Generator Blowdown Sampling Exceeded Required Periodicity of Tech Specs 3.3.3.1,Action 28.Caused by Personnel Error.Procedures Being Revised to Verify That Monitor Inservice & Sampling Done
05000321/LER-1988-009-02, :on 880520,reactor Scram Occurred When Three MSIVs Less than 90% Opened.Caused by Procedure Deficiency. Nitrogen to MSIVs Restored,Plant Procedures Temporarily Revised & Permanent Revs Scheduled
05000293/LER-1988-016, :on 880517,unexpected Actuation of Inboard Portion of Reactor Bldg Isolation Control Sys Occurred, Resulting in Closure of Train a Isolation Dampers.Caused by Personnel Error.Work Process Revised
05000366/LER-1998-004-04, :on 981005,condition Prohibited by TS Was Noted.Caused by Personnel Error.Coached Involved Personnel & Briefed Other Technicians on Event.With
05000316/LER-1986-008, :on 860311,ESF Reactor Trip Signal Received Due to Control Power Wires Pulling Free from power-range Nuclear Instrument Drawer & Shorting Out.Caused by Faulty Electrical Connector & Mislabeled Doors
05000213/LER-1988-014, :on 880511,determined That Effluent Sample Pump P-8-1A Taken Out of Svc for Maint on 880510 Rendering Svc Water Effluent Radiation Monitor R-18 Inoperable.Caused by Personnel Error.Instruction Written
05000315/LER-1986-003-01, :on 860228,evaluation of Noncompliance Rept (NCR) RQA-86-03-1 Concluded Certain Fire Protection Piping W/O Seismic Restraints Previously Installed Over safety-related Components.Also Reportable Per Part 21
05000388/LER-1986-004-01, :on 860115,reactor Manually Scrammed Due to Overheating of Phase Main Transformer B.Caused by Improper Alignment of Knife Switches to Transformer Cooling Loops. Knife Switches Corrected
05000237/LER-1986-003-06, :on 860226,pumpdown of Drywell Equipment & Floor Drain Sumps Not Performed at Proper Interval.Caused by Operator Error & Equipment Malfunction.Horn Replaced & Operators Made Aware of Error
05000414/LER-1988-017-01, :on 880424,main Feedwater Isolation Occurred Due to hi-hi Level Turbine Trip Signal from Steam Generator. Caused by Personnel Error.Steam Generator Levels Brought Under Control Using Auxiliary Feedwater
05000366/LER-1988-012, :on 880421,surveillance Requirements Not Met Due to Failure to Test Response Time of Isolation Actuation Instrumentation.Caused by Procedure Inadequacy.Special Purpose Procedures Developed & Performed
05000366/LER-1988-013, :on 880415,during Performance of Functional Test Procedure to Return Hydrogen Recombiner to Svc,Failure to Test Piping Violated Primary Containment Integrity.Caused by Personnel Error.Isolation Valves Closed
05000321/LER-1988-002-01, :on 880410,reactor Protection Sys Actuation Occurred & Outboard Valves of Primary Containment Isolation Sys Valve Group 2 Isolated.Caused by Personnel Error.Event Reviewed W/Involved Personnel
05000409/LER-1986-005, :on 860124,high Pressure Svc Water/Alternate Core Spray Diesel 1A Removed from Svc to Replace Weeping Cooling Water Pump Discharge Hose.Surveillance Test Conducted Following Hose Replacement
05000413/LER-1988-016-02, :on 880310,sliding Links on Safety Cabinets Left in Open Position Due to Possible Personnel Error. Sliding Links Returned to Correct Positions & All Other Safety Cabinets Inspected
05000382/LER-1988-005, :on 880321,blown Undervoltage Circuit Fuse Replacement Results in Tech Spec 3.0.3 Entry.Caused by Inadvertent Shortening of Two Wire Connections.Change to Tech Spec Being Pursued to Correct Deficiency
05000382/LER-1987-029, :on 870402,failure to Meet Safety to Nonsafety Electrical Distribution Separation Criteria Discovered. Caused by Cognitive Personnel Error in Developing Design Changes.Sys Expert to Review Design Changes
05000029/LER-1988-001, :on 880126,procedure Inadequacy Discovered That Could Allow Insufficient Load Testing of Emergency Generators.Caused by Inadequate Procedure Review.Procedure Change Notice Prepared & Test Completed
05000382/LER-1988-015, :on 880613,plant Shutdown Required Due to Leakage Past Reactor Coolant Loop Drain Valves.Caused by Inadequate Hand Closing One of Drain Valves.Valves Will Be Evaluated & Corrective Action Recommended
05000413/LER-1988-009, :on 880206,Limitorque Valve Actuator T-drains Found Painted Over or Missing on 27 Valves.Caused by Lack of Communication & Mgt Deficiency.Painters Will Receive Periodic Retraining.Drains Repaired
05000285/LER-1997-009, :on 970619,potential Loss of Remote Shutdown Capability Occurred Due to Fire Induced Damage.Caused by Inadequate Design Basis Documentation.Operations Memo Provided Evacuation Criteria
05000285/LER-1997-008, :on 970616,improper Shift Staffing Due to Inadequate Control of Respirator Spectacle Kits Occurred. Caused by Program for Obtaining Corrective Lenses Inadequate to Ensure Compliance w/10CFR.Manual Revised
05000269/LER-1987-012, :on 871203,discovered Exam Frequency of Reactor Coolant Pump Flywheels Exceeded Requirement of Tech Spec 4.2.3.Caused by QA Deficiency.Inservice Insp Plan Revised
05000267/LER-1987-031, :on 871225,hot Reheat Temp High Scram Occurred. Caused by Operator Inattention to Plant Conditions.Reactor Returned to Power on 871227 & Consequences of Inattention to Plant Parameters Reviewed W/Operator
05000413/LER-1987-046, :on 871219,main Feedwater CF Isolation Occurred During Removal of Temporary Station Mod (Tsm) from Solid State Protection Sys.Caused by Mgt Deficiency.Tsm Removed & CF Sys Returned to Alignment
05000414/LER-1987-031-02, :on 871221,discovered No Performance Retest Conducted on Diesel Generator 2B Starting Air Inlet Valves Repaired on 871119.Caused by Personnel Error.Retest Satisfactorily Completed
05000414/LER-1988-008-01, :on 880224,Tech Spec Violation Due to Implementation of Inadequate Compensatory Measures.Caused by Mgt Deficiency.Monitoring Instrumentation Returned to Svc Before Reduction in Reactor Temp Initiated
05000338/LER-1988-003, :on 880107,Tech Spec 3.3.3.1,Action Statement 35 Exceeded.Caused by Radiation Monitor 1A Being Inoperable for More than 72 H Due to Ion Chamber Problems.Grab Samples Taken & Ion Chamber & Tube Replaced
05000277/LER-1988-002-01, :on 880301,reactor Scrammed During Performance of Procedure GP-11.E, Reactor Protection Sys (RPS) - Scram Reset. Caused by Operator Error.Operator Counseled Re Importance of Attention to Detail
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
05000413/LER-1988-011, :on 880126,nuts Received W/O Proper Charpy Impact Testing Documentation.Caused by Mfg Deficiency & Personnel Error.Incident Reviewed W/General Ofc QA Personnel.Nuts Tested Per NRC Bulletin 87-002
05000293/LER-1987-020, :on 871217,fire Damper CPR-2 Failed to Close. Caused by Clover Hook Catching on Edge of Damper Blade.Hooks Changed So Open Side of Hook Faces Away from Damper Blades
05000328/LER-1988-003-02, :on 880119,discovered Ice Buildup in Flow Passages of Ice Condenser Due to Sublimation.Cause Not Determined.Ice Condenser Defrosted & Special Maint Instruction Performed
05000285/LER-1997-004, :on 970505,DG Was Outside Design Basis Due to Violation of App R.Mod Was Completed on 970507 to Provide Ability to Isolate CR Located Tachometer from DG-2 Speed Sensing Circuit Prior to Reaching 300 Degrees
05000370/LER-1986-004-03, :on 860321,during Maint,Esf Actuation Occurred Immediately Following Attempts to Remove Broken Drill Bit from Control Board.Cause Undetermined.Incident Will Be Reviewed as Supplementary Personnel Training
05000414/LER-1997-004-03, :on 970424,inadequate Test of Containment Isolation Valve Identified.Caused by Inadequate Work Practices.Personnel Involved Counseled Re Improved Performance
05000315/LER-1985-043, :Corrective Actions & Preventive Measures Taken Re Discrepancies in Process Sensor Calibr Completed,Per Confirmatory Action Ltr Issued on 850820
05000458/LER-1997-002-03, :on 970506,small Leak at Inlet of Vent Valve for RRS FCV B.Root Cause Is Undetermined.Valve Was Replaced Prior to Returning to Power Operations
05000251/LER-1985-026-01, :on 851224,480-volt Power Supply Breaker to Backup Group 4A Pressurizer Heaters Discovered to Have No Light Indication.Caused by Backing Off Action by Arcing Contacts.Breaker Manually Tripped
05000369/LER-1986-005, :on 860207,during Insp Exit Interview, Determined That Containment Sump Isolation Valves 1NI-184B & 1NI-185A Not Visually Inspected at Least Once to Verify Remote Position Indication
05000413/LER-1985-058, :on 851008,hourly Fire Watches for Nine Fire Detection Zones Performed Approx 30 Minutes Late.Caused by Lack of Formalized Program to Document Post Assignments or Changes in Assignments.Patrols Performed
05000289/LER-1997-002, :on 970129,potential Inability of Startup Feedwater Block Valves to Fully Close Following Main Steam Line Break Occurred Due to MOV Program Weakness.Increased Torque Switch Settings on Valve Operators
05000250/LER-1985-032, :on 851015,at 100% Power,Main Transformer Relay Actuated,Resulting in Electrical Generator Trip & Turbine Trip.Probably Caused by Jarring of Relays by Const Personnel
05000250/LER-1985-021-01, :on 850722,two Automatic Initiations of Auxiliary Feedwater Sys Occurred Due to Bypass Feedwater Control Valves Malfunctioning.Caused by Moisture in Instrument Air.Actuators Inspected & Cleaned
05000275/LER-1985-036, :on 851119,discovered That Safety Injection & Charging Pump Suction Crosstie Valve Surveillances Not Performed Since 850814.Caused by Personnel Error.Test Performed
05000275/LER-1985-029, :on 850821,containment Sump Level wide-range Channel Check Not Performed.Caused by Failure to Incorporate Requirement Into Surveillance Test Procedure (STP) I-1D. Requirement Incorporated.Test Performed
05000369/LER-1985-029-01, :on 851001,Westinghouse Notified Util That Reanalysis of Peak Containment Pressure Calculation Resulted in Greater Value than Internal Pressure of 15 Psig.Emergency Procedure for Nd Spray Initiation Revised
05000327/LER-1985-046-01, :on 851118,annulus Fire Hose Stations Found Isolated.Caused by Unit Operator 851114 Erroneous Isolation of Header After Inadvertent Opening of Containment High Pressure Fire Protection Valve.Header Restored
05000318/LER-1997-001-01, :on 970401,refueling Machine Overload Protective Circuitry Was Inoperable Due to Failure to Correctly Translate Refueling Machine Circuitry Design Into Ts.Mod to Overload Bypass Was Installed
05000366/LER-1997-005-01, :on 970402,unplanned Automatic Engineered Safety Feature Actuation Occurred Due to Personnel Error. Emergency Bus 2F Was Returned to Svc on 970402
05000213/LER-1985-028, :on 851110 & 21,during Coastdown,High Steam Flow (Hsf) Reactor Trips Occurred Due to Automatic Reactor Protection Sys Initiation.Caused by Communication Between Hsf Channels 1,2 & 4.Loop 3 Solenoids Replaced
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
05000275/LER-1985-032, :on 850912,QA Insp Disclosed Absence of Nuts on Embedded Plate for Main Feedwater Piping Snubber Support. Caused by Const & Engineering Misunderstandings of Design Details.Nuts Installed & Plate Stiffened
05000270/LER-1986-002-03, :on 860204,reactor Tripped on Flux/Flow Imbalance When Safety Control Rod Dropped in Core.Caused by Personnel Error.Crd Dc Breakers Reset & Procedures Will Be Changed
05000498/LER-1997-004, :on 970319,failed to Fully Test 4160 Volt Bus Undervoltage Logic Circuitry by Surveillance Procedures. Caused by Not Recognizing That Failure in One Actuation Scheme.Affected Logic Circuitry Was Tested
05000413/LER-1985-071, :on 851220,reactor Trip Occurred.Caused by Equipment Malfunction.Work Request Initiated to Investigate & Repair Steam Generator Feedwater Control Valve 1CF28
05000395/LER-1985-019, :on 850723,grab Samples Not Obtained While Turbine Bldg Sump Radiation Monitor Inoperable.Caused by Personnel Oversight.Addl Controls to Process Surveillance Test Task Sheets Established
05000409/LER-1985-018, :on 851023,high Flux Scram Alarm Received on Nuclear Instrumentation Channel 6.Caused by Malfunction in Oscillator Circuit on Trip Stage.Step Added to Plant Startup Procedure to Ensure Recorders on
05000323/LER-1985-009-01, :on 851022,generator & Reactor Trip Occurred. Caused by Technician Inadvertently Actuating Current Test Block of Main Generator Differential Relay.Technician Counseled & Instructions Installed on Panel
05000323/LER-1985-012-01, :on 851017,review of Completed Surveillance Test Procedure Data Sheet Determined Three Feedwater Control Valves Had Exceeded Closure Time Requirements of Tech Spec Table 3.3-5.Caused by Personnel Error
05000346/LER-1985-013, :on 850609,main Feedwater Pump 1 Tripped on Overspeed Due to Control Problem.Reactor Also Tripped on High RCS Pressure Because of Inadequate Feedwater.Corrective Actions Not Yet Determined
05000269/LER-1985-013-03, :on 851019,gaseous Waste Disposal Tank 1C Pressurized & Isolated W/O Taking Hydrogen Concentration Sample Per Tech Spec 4.1.3.Caused by Personnel Error.Tank Sampled & Analyzed After Discovery
05000333/LER-1997-003, :on 970213,identified Potential Overpressurization of Containment Penetrations Due to Thermal Expansion.Caused by Original Plant Design.Completed Operability Determinations IAW GL 91-18
05000382/LER-1985-050, :on 851202,04 & 09,fire Watch Tours Not Conducted.Caused by New Employees Unfamiliar W/Facility Health Physics Controls Requiring Dress Out Before Entering Area.Employee Terminated on 851209
05000321/LER-1997-002-01, :on 970207,determined TS Surveillance Requirement 3.8.1.9 Had Not Been Adequately Implemented. Caused by Less than Adequate Procedures in Logic Sys Functional Test.Operating Order Issued
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
05000304/LER-1985-005-09, :on 850806,discovered That Svc Bus Undervoltage Start of steam-driven Auxiliary Feedwater Pump Not Tested Per Tech Spec Table 4.4-1.Procedure PT-5C Prepared & Will Be Placed on Surveillance Schedule by 851115
05000346/LER-1997-002, :on 970122,identified Potential Overpressurization of Penetrations During Accident Conditions.Plant Mods & Procedure Changes Being Developed to Prevent Overpressurization of Piping
05000285/LER-1997-001, :on 970122,main Steam Outside of Design Basis Occurred Due to an Error in Safety Valve Analysis.Guidance Has Been Provided to Operating Staff to Ensure That Design Basis Maintained
05000285/LER-1996-010, :on 961018,loss of Containment Closure Noted Due to Maint Activity During Refueling.Station Procedures Including OI-CO-4,will Be Reviewed & Revised as Necessary to Ensure Adequate Controls Exist
05000250/LER-1985-022, :on 850729,reactor Trip Occurred.Caused by Dirty Contacts on One Nuclear Instrumentation Sys Channel. Power Range Trip Relays Removed,Cleaned & Reinstalled
05000327/LER-1995-001-01, :on 950118,accumulation of Gas in Residual Heat Removal Sys.Caused by Normal Leakage from Cold Leg Accumulators.Performed Monitoring & Venting of Gas Accumulation & Revised Quarterly Pump Tests
05000338/LER-1996-009, :on 961010,determined Missed Surveillance Occurred W/Reactor Trip Bypass.Caused by Inadequate Surveillance Test Procedures.Revised Procedure Controlling Reactor Trip Bypass Breaker
05000483/LER-1985-034, :on 850718,trip Occurred as Result of Power Range High Negative Flux Rate Signal.Caused by Inadequate Cooling of Rod Drive Power Cabinet.Caution Tag Added to Handswitch Controlling Room Cooler
05000285/LER-1996-007, :on 961005,unplanned Reactor Protection Sys Actuation Occurred During Plant Cooldown.Caused by Failure to Complete Step in OP-3A as Required.Procedure Revised.W/
05000315/LER-1985-028, :on 850613,fire Barrier Seals Located Above Walls Separating Control Room Cable Vault & Hot Shutdown Panel Cable Room Not Installed in Accordance W/Design Specs. Cause Not Stated.Permanent Seal Installed
05000483/LER-1985-032, :on 850715,alarm in Fire Detection Zone 308 Activated by Cooking in Control Room Pantry But Not Reset. Remaining Zone 308 Fire Detectors Inoperable.Alarm Reset.Mod Request Initiated
05000338/LER-1985-011-01, :on 850918,emergency Diesel Generator 1J Tripped on High Crankcase Pressure & Repairs Not Completed within 72 H,Causing Cold Shutdown on 850921.Caused by Cracked Cylinder Liner.Liner Replaced
05000498/LER-1996-005, :on 961213,reactor Containment Building Personnel Airlock Incorrectly Declared Operable Occurred. Caused by Pertinent Information Re Status of Seal Replacement.Occurrence Has Been Reviewed
05000213/LER-1985-025, :on 850919,unplanned Release of Radwaste to Environ Detected.Caused by Isolation Valve Left Open Through Operator Error & Ambiguous Valve Tag Numbers.Event Reviewed W/Operators & Valves Relabeled Clearly
05000295/LER-1985-033-04, :on 850913,manual Quadrant Power Tilt Ratio (QPTR) Calculations Not Performed W/Qptr Alarm Inoperable. Caused by Personnel Error.Channel Returned to Normal.Shift Meetings Held
05000213/LER-1985-016, :on 850703,ex-core Channel Failed to Meet Acceptance Criteria for Dropped Rod Load Runback Setpoint During Nuclear Instrumentation Sys Surveillance.Caused by Setpoint Drift.Setpoint Recalibr
05000304/LER-1985-012-07, :on 850702,purge Valves Closed on High Radiation Signal from Containment Purge Exhaust Noble Gas Monitor.Caused by Procedural Deficiency Resulting in High Alarm Setpoint Set Too Low.Procedure Revised
05000382/LER-1985-031, :on 850704,main Feedwater Pump a Tripped Due to High Vibrations on Feedwater Pump Turbine.No Apparent Cause Noted.Alarming Function Will Remain in Place to Alert Personnel of Vibration Increase
05000388/LER-1985-022-01, :on 850703,instrumentation & Controls Technician Inadvertently Connected Test Equipment to Electronics Module for Reactor Water Cleanup Sys.Technician Counseled.Rear Input Wires Labeled
05000369/LER-1985-007-03, :on 850205,two ESF Actuations Occurred During Work on Reactor Protection & Nuclear Instrumentation Sys Channels.Caused by Procedures Allowing Simultaneous Sys Work.Procedures Revised
05000259/LER-1985-036, :on 850626,during Evaluation,Discovered That Addl RCIC & HPCI Sys Isolation Valves Not Local Leak Tested (Type C) Per 10CFR50,App J.Caused by Incomplete App J Program.Valves Added to Program
05000395/LER-1985-026, :on 850908,at 100% Power,Turbine Driven Emergency Feedwater Pump Indicator Read 250 Rpm.Caused by Seat Leakage Past Steam Supply Control Valve.Valve Repaired & Reset
05000369/LER-1985-018-01, :on 850525,valve 1RV-429 in Containment Ventilation Cooling Water Sys Outside Containment Found Open,Allowing Flow Path Between Auxiliary Bldg & Upper Containment Through Inside Containment Valve
05000213/LER-1985-008, :on 850320,during Test of Fire Protection Sys, Actuation of Carbon Dioxide Sys Failed to Shut Off Containment Cable Vault Exhaust Fan.Caused by Wiring Error. Exhaust Fan Rewired
05000382/LER-1985-028, :on 850627,DNBR & Local Power Density Trip Generated,Resulting in Actuation of Reactor Protective Sys. Caused by Control Element Assembly Position Deviation.Ler to Be Emphasized During Operator Training
05000409/LER-1985-013, :on 850701,09,10 & 12,high Pressure Svc Water diesel-driven Pump 1A Malfunctioned.Caused by Air in Fuel Line.Priming Tank Refilled & Diesel Fuel Filters Vented
05000370/LER-1985-018-02, :on 850624,unit Tripped Due to Low Level of Steam Generator 2C.Caused by Valve 2CF-28 Closure Due to Solenoid Failure.Valve Repaired.Steam Leak Discovered in Auxiliary Feedwater Sys & Repaired
05000213/LER-1984-010, :on 840803,RCS Low Pressure Overpressure Protection Safety Valves Opened.Cause Not Determined.Valves Dismantled & Repaired & Wide Range RCS Pressure Transmitters Replaced
05000249/LER-1985-016-07, :on 850826,equipment Attendant Observed HPCI Room Cooler Fan Breaker Emitting Smoke.Caused by Shorted Motor Contactor Coil.Coil & Auxiliary Contacts Replaced & Maint Procedure DMP 7300-5 Performed
05000269/LER-1985-012-03, :on 850819,determined That Several Reactor Bldg Tendon Insps Not Performed & Insp Repts Not Sent to NRC on Time.Caused by Misinterpretation of Tech Specs. Administrative Directives Revised
05000245/LER-1996-026-01, :on 960321,failure to Perform Type C Leakage Test in Accordance W/Requirements of 10CFR50 App J Identified.Caused by Personnel Error.Mods to Penetrations X-8,X-9A & X-9B Implemented
05000266/LER-1996-010, :on 961112,EDG Governor Failure Was Noted. Caused by Dislodging of Spring Clip in Synchronizer Indicator Assembly.Spring Clip Was Replaced W/Spare & EDG & Governor Were Tested,Per RMP-110B & TS-81
05000321/LER-1996-012, :on 961008,ground on 600-volt Bus Causes Loss of RPS Power Supply & Unplanned ESF Sys Actuations.Caused by nonfault-tolerant Design.Cable & Heater Replaced & Use of Breaker Trip Devices Investigated
05000413/LER-1985-028, :on 850422,both RHR Trains Inoperable & RCS Draining Began While Train a Inoperable Due to Maint.Caused by Personnel Error.Centrifugal Charging Pump a Started to Restore PCS Sys Level
05000318/LER-1996-004-01, :on 960926,missed Surveillance Occurred Due to Less than Adequate Technical Review of Stp.Procedures Revised
05000369/LER-1985-020-01, :on 850607,diesel Generator 1B Experienced Two Invalid Automatic Starts.Caused by Power Distribution Sys Disturbances Due to Severe Weather.Start Sys Will Be Modified
05000237/LER-1985-021-02, :on 850503,during Shutdown,Two Reactor Scrams Occurred from Intermediate Range Monitors 13 & 15 hi-hi Condition.Caused by Spurious Radio Repeater Signals. Relocation of Radio Repeaters Initiated
05000483/LER-1985-024, :on 850506,reactor Trip/Turbine Trip Occurred as Result of Steam Generator lo-lo Level Signal.Caused by Electronic Failure in Governor Controller of Main Feedwater Pump B.Component Replaced
05000270/LER-1985-005-04, :on 850426,unit Tripped from 75% Power on High RCS Pressure.Caused by Increase in Pressure Due to Spurious Signal from electro-hydraulic Controls Cabinet Due to Component Failure/Malfunction
05000295/LER-1985-021-04, :on 850603,when Instrument Bus Switched from Alternate to Normal Power,Momentary Power Loss Caused Reactor Trip.Caused by Switching Procedure Not Being Referenced.Warning Sign Placed at Switch
05000388/LER-1985-015-01, :on 850421,spray Pond Bypass Valve HV-01222A Did Not Automatically Open When Emergency Svc Water Pump a Started.Caused by Two Open Sliding States Link Terminal Blocks in Relay Panel.Links Evaluated
05000295/LER-1985-019-04, :on 850607,reactor Trip Resulted in High Steam Flow Safeguards Actuation,Closing All Msivs.Caused by Failure of Summator,Which Spiked Low.Module Replaced
05000259/LER-1985-008, :on 850318,HPCI & RCIC Turbine Exhaust Valve Flanged Bonnets Not Local Leak Tested in Accordance w/10CFR50,App J Requirements.All Valves Will Be Repaired & Pass Leak Test
05000315/LER-1985-027, :on 850604,during Hydrostatic Testing,Three 8-inch Diameter Fire Penetrations Found Nonfunctional.Cause for Removal of Silicone Foam Undetermined.Openings Sealed & Safety Evaluation Performed
05000296/LER-1984-013, :on 841122,during Startup After Cycle 5 Refueling,Hpci Outboard Steam Supply Isolation Valve Failed to Open.Caused by Motor Pinion Gears Being Installed Backwards.Gears Replaced in Proper Direction
05000338/LER-1996-004-01, :on 960910,seismic Concerns Were Noted Re Containment Particulate & Gaseous Radiation Monitors.Caused by Personnel Error.Rms Were Declared Inoperable & RCS Leak Rate Calculations Were Initiated
05000369/LER-1985-014-01, :on 850507,core Alterations Started W/O Completion of Required Surveillance on Source Range Neutron Flux Monitors While in Mode 6.Caused by Administrative/ Procedural Deficiency.New Procedure Planned
05000370/LER-1984-017-01, :on 840806,broken Weld on RHR Sys Letdown Line to Chemical & Vol Control Sys Discovered.Insp Revealed Number of Supports/Restraints Damaged.Caused by Loose Packing in Valve.Damaged Piping Replaced
05000259/LER-1985-013-01, :on 850418,util Ofc of Engineering Determined That Existing Configuration of Startup Test Instrumentation Panels Cannot Be Determined to Be Seismically Qualified. Caused by Improper Mounting of Panels
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
05000369/LER-1985-015-02, :on 850508,auxiliary & Reactor Bldg Side Door Lower Airlock Seals Deflated,Causing Loss of Containment Integrity.Caused by Maladjustment of Airlock Door Pin Limit Switches Combined W/Design Deficiency
05000409/LER-1985-009, :on 850421,leak Developed in Seal Inject Supply Line to CRD Mechanisms.Caused by Rupture in High Pressure Hose Between Flow Orifice & Transmitter.Reactor Shutdown & Hose Plugged
05000369/LER-1985-016-01, :on 850508,discovered That Temp Compensation Chart Not Incorporated in Hydrogen Analyzer Operation Emergency Procedure.Caused by Procedural Deficiency.Temp Compensation Charts Incorporated in Procedure
05000369/LER-1985-013-01, :on 850502,during Refueling,Gearcase Lubricating Grease Found in Electrical Compartments of Limitorque Motor Operated Valve Actuators 1VX-1A & 1VX-2B. Caused by Error During Previous Maint Work
05000413/LER-1984-032, :on 841219,seven Inoperable Fire Barrier Penetrations Discovered.Caused by Failure to Follow Procedures During Cable Pulling Activities.Penetrations Resealed.Personnel Will Be Retrained
05000370/LER-1985-012-02, :on 850508,during Attempt to Swap Main Feedwater Pump 2A from Auxiliary to Main Steam Supply,Pump Tripped on High Discharge Pressure.Caused by Control Sys Not Responding to Speed Controller
05000424/LER-1996-009-01, :on 960808,leaking Valve Results in Fuel Handling Bldg Isolation.Down Stream Needle & Relief Valves Were Replaced
05000328/LER-1996-001-05, :on 960418,inadvertent ESF Actuation & Loss of Power Signal & Load Sequencing Occurred During Maint. Caused by Personnel Error.Individual Involved in Event Was Counseled & Lessons Were Discussed
05000416/LER-1985-015, :on 850404,RCIC Sys Inadvertently Isolated When Bypass Switch Mistakenly Returned to Normal During Testing.Caused by Misunderstanding Between Personnel.Sys Restored.Need for Clear Communication Stressed
05000416/LER-1985-013, :on 850403,reactor Scrammed on High Water Level During Startup Testing.Caused by Failure of Level Channel Selector Switch.Switch Replaced & Precautionary Steps Added to Operating Instructions
05000327/LER-1985-004-01, :on 850116,surveillance Instructions (SI) on Fire Doors Not Performed within Tech Spec Time Limits.Caused by Personnel Error.Ltr Written to Personnel Stressing Correct Performance of SIs
05000278/LER-1992-008-03, :on 921015,full PCIS Group I Actuation Occurred Which Caused Reactor Scram.Caused by Unexpected Actuation of Isolation Pressure Switches.Pcis & RPS Scram Logic Reset & Affected Sys Restored
05000416/LER-1996-004-03, :on 960606,manual Reactor Scram Occurred Due to Spurious Multiple SRV Lifts.Replaced Trip Unit Card in Addition to Functionally Checking Other Card Files in Same Panel
05000382/LER-1996-013-01, :on 960822,possible Operation in Excess of 100% Licensed Power.Cause Is Being Investigated
05000318/LER-1996-002-01, :on 960522,fire Watch Missed.Caused by Personnel Error.Counseled Personnel Re Event
05000219/LER-1996-005, :on 960430,reactor Scram Occurred on Low Water Level Due to Personnel Error.Discussion of Event Issued to Operators & Interim Guidance Issued to Operators on Reactor Water Level Control
05000413/LER-1985-014, :on 850222,stainless Steel Valves Discovered Installed W/Carbon Steel Filler Matl.Caused by Const Isometrics Incorrectly Specifying Matls Which Led to Use of Incorrect Welding Procedure
05000413/LER-1985-015, :on 850302,breakers Not Locked in Off Position on Certain Safety Injection & Auxiliary Feedwater Pump Motors.Caused by Administrative Deficiency & Personnel Error.Procedure Revised
05000285/LER-1996-004, :on 960315,discovered Adequate Shutdown Margin Was Not Maintained.Caused by Inadequate Technical Review by Plant Personnel Involved in Reviewing Procedure Change. Appropriate Personnel Trained on Incident
05000370/LER-1984-031, :on 841124,trip Occurred Due to Failure of Loop Power Supply Card in Process Control Sys Causing Downward Spike in Channel of Overtemp Differential Temp Setpoint Circuit.Caused by Poor Cable Connection
05000413/LER-1984-025-03, :on 841127,motor Driven Auxiliary Feedwater Pumps Started After Loss of Main Feedwater Pumps When Reactor Trip Breakers Opened to Support Rod Drop Timing Test.Caused by Personnel Error
05000413/LER-1985-009, :on 850131,during Loss of Control Room Functional Test,Safety Injection Occurred.Caused by Component Malfunction.Safety Injection Reset,Closing Cold Leg Safety Injection Valve
05000259/LER-1996-003-03, :on 960403,Unit 2 Received Unplanned ESF Actuation.Caused by Electrician Introduced Fault Into ECCS Logic While Preparing Wires for Termination in Panel 2-9-81. Problem Evaluation Rept Initiated
05000416/LER-1985-006, :on 850207,RCIC Turbine Steam Supply Inboard Isolation Valve Isolated on Spurious RHR Equipment Area High Ambient Temp Signal.Cause Undetermined.Alarm Invalid & RCIC Sys Returned to Standby
05000370/LER-1985-001-02, :on 850123,nuclear Svc Water Sys Valve 2RN-158 Found W/O Lock & Chain Installed.Caused by Personnel Error. Procedures Will Be Reviewed & Revised,If Necessary,To Reflect Proper Locked Valve Requirements
05000327/LER-1984-063, :on 841018,noncompliance of safety-related Sys w/10CFR50,App R Noted.No Cause Stated.Fire Watches Utilized. Implementation Schedule of Corrective Actions Expected by 850101
05000285/LER-1996-002, :on 960329,reactor Manually Tripped Due to Partial Loss of Vacuum in Main Condenser.Condenser Isolated, Plant Shutdown & Leaking Condenser Tube Plugged.Pm Order WP-006820 Will Be Revised
05000370/LER-1984-025, :on 840826 & 30,turbine Driven Auxiliary Feedwater Pump Experienced Reverse Rotation,Causing Overpressurization of Pump Suction Piping.Caused by Leaking Swing Check Valve.Leaking Valve Replaced
05000413/LER-1985-006, :on 850120,hot Standby Initiated After Reactor Coolant Average Temp Could Not Be Increased to Greater than 541 F 15 Minutes After Temp Decrease During Performance of Natural Circulation Verification Test
05000352/LER-1985-008, :on 850112,reactor Water Cleanup Sys Isolated. Caused by Blown Fuse in Nuclear Supply Shutoff Sys Logic. Fuse Replaced
05000370/LER-1984-024, :on 840916,abnormally High Number of rate-of-rise Fire Detector Failures Discovered in Diesel Generator 2B Room.Caused by Improper Detector Application. Detectors Replaced
05000296/LER-1985-003-02, :on 850111,during Scheduled Test,Hpci & RCIC Sys Failed to Reach Rated Flow within Allotted Time.Hpci Sys Declared Inoperable.Caused by Incorrect Setting of Limit Switch
05000328/LER-1985-002-02, :on 850112,reactor Tripped on lo-lo Steam Generator Level & Train a Reactor Trip Breaker Failed to Open Automatically.Caused by Failure of Pump Discharge Valve LCV-6-106A.Valve Repaired
05000413/LER-1985-003, :on 850109,during Monthly Testing of Solid State Protection Sys,Reactor Trip Breaker Opened on High Flux Source Range Reactor Trip Signal.Caused by Procedural Deficiency.Procedure Revised
05000370/LER-1984-034, :on 841221,reactor Actuation Occurred When Inverter Erroneously Removed from Svc.Caused by Operator Failing to Properly Identify Component to Be Removed from Svc.Personnel Counseled.Trip Setpoints Reset
05000327/LER-1996-002-01, :on 960215,SRs Associated W/Fire Protection Hose Stations Not Performed as Required by Ts.Caused by Inadequate Procedure Rev.Entered Action of LCO & Established Measures to Address Issue
05000354/LER-1996-001, :on 960113,safety & Turbine Acs Heat Exchangers Fouled W/Detritus Occurred Due to Failed Svc Water Strainer. Strainers Replaced & Enhanced Maint & Design Mod
05000369/LER-1984-028, :on 840712,design Deficiency Reported in Relief Capacity of Component Cooling Water Sys Surge Tank.Cause Not Stated.Increased Relief Capacity for Surge Tanks Will Be Added
05000413/LER-1985-019, :on 850307,during Performance of Analog Channel Operational Test,Steam Generator C Level Channel 4 Found Inoperable.Caused by Personnel Error.Circuit Card Replaced
05000269/LER-1985-003-02, :on 850222,emergency Safeguard Features Actuation Sys Setpoint Adjusted to 1,600 Psig.Caused by B&W Reanalysis of Small Break LOCA Transients,Per NUREG-0737. Setpoint Changes Initiated
05000395/LER-1985-003, :on 850228,during Reactor Startup,Reactor Trip Occurred on High Flux Positive Rate Trip.Caused by Operator Failure to Adhere to Procedures.Operator Counseled. Procedures Revised
05000528/LER-1985-010, :on 850222,automatic Actuation of balance-of- Plant ESF Actuation Sys Occurred When Placing Train a Sequencer in Manual from Automatic Mode.Caused by Unique Circumstances Involving flip-flop U-14
05000281/LER-1985-002-03, :on 850215,svc Water Isolated to Charging Pump Intermediate Seal Cooler & Component Cooling Water Isolated.Caused by Valve Misposition Due to Operator Error. Valve Repositioned & Personnel Counseled
05000328/LER-1985-004-02, :on 850215 & 17,reactor Trips Occurred Due to lo-lo Steam Generator Water Level.Caused by Personnel Error & Failed Filter Cartridge Cover.New Cover Installed & Personnel Counseled
05000416/LER-1985-009, :on 850215,ESF Actuated Due to Pressure Disturbance on Instrument Ref Leg.Caused by Technician Restoring Vessel Level Instrument to Svc.All Sys Returned to Normal Status
05000413/LER-1984-018-02, :on 841023,in-core Thermocouple Tube Leakage Occurred.Caused by Separation of Stainless Steel Conduit from Swagelok Tube Fitting.Thermocouple Replaced
05000261/LER-1985-008, :on 850203,short Circuit on Terminal Board for Radiation Monitor R-21 Vacuum Pump Occurred.Caused by Decontamination Activities Using Pressurized Water.Faulty Circuit Isolated & Feeder Breaker 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
05000328/LER-1984-014-01, :on 840830,lo-lo Steam Generator Reactor Trip Occurred.Caused by Main Feedwater Isolation Valve Failing to Close Due to Stuck Contact & Main Feedwater Pump B Reset Due to Incorrect Solenoid Valve Setting
05000261/LER-1985-007-01, :on 850128,four 480-volt Undervoltage Relays on Emergency Buses E1 & E2 Discovered Out of Tolerance. Caused by Overly Restrictive Tech Spec Setpoint Description. Tech Spec Rev Requested
05000269/LER-1984-003-04, :on 840830,post-irradiation Exam Gamma Ray Scanner Rotated So One End Momentarily Suspended Over Spent Fuel Assembly in Spent Fuel Pool.Caused by Insufficient Number of Spent Fuel Assemblies
05000328/LER-1992-008, :on 920627,reactor Tripped.Caused by Varying Resistance Readings Substandard Workmanship.Plant Instruction Written to Provide Guidance
05000327/LER-1995-019, :on 951225,manual Reactor Trip Occurred as Result of Main Generator Exciter Problems.Caused by Field Pole Failure in Main Generator.Replaced Exciter
05000285/LER-1995-008, :on 951204,inadequate Trisodium Phosphate Was in Containment Due to Calculation Error.Revised Appropriate Calculations for Future Operating Cycles
05000298/LER-1992-005, :on 920325,RCIC Sys Declared Inoperable Due to Evidence of Water in Turbine Casing.Caused by Malfunctioning Turbine Exhaust Line Steam Trap.Steam Trap Removed & Cleaned & Internals Installed
05000382/LER-1995-005-04, :on 951102,calibr Input Data for Rosemount Instrument Transmitters Was in Error.Caused by Ineffective Review Process for Instrument Calculations.Established Administrative Control for SIT Level Control
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
05000327/LER-1995-013, :on 951010,surveillance Was Missed During Mode 6.Caused by Inadequate Training of Licensed Operators in Use of 12-wk Schedule.Revised Procedures to Include Comprehensive List of Routine SIs
05000219/LER-1995-007, :on 951010,TS Required Surveillance Was Missed Due to Administrative Error.Nuclear Safety Assessment Group Performed Audit of Past Surveillance Activities
05000348/LER-1995-009, :on 951008,classified Results of SG Tube Insps Performed During Unit 1 Thirteenth Refueling Outage of 328 Tubes as Category C-8 Due to 3.34% of Tubes Inspected Being Defective.Required Tubes Plugged or Repaired
05000327/LER-1984-064, :on 840925,inadvertent Trip Occurred on lo-lo Steam Generator Level in Loop 1.Caused by Pressure Decrease Due to Opening MSIV FCV-1-4 for Loop 1.Precautionary Note Added to GOI-1
05000331/LER-1984-021, :on 840617,during Surveillance Test for Standby Diesel Generator B Operability,Diesel Tripped on High Crankcase Pressure While Loaded to Approx 2,400 Kw.Caused by Scavenging Air Blower Failure.Blower Repaired
05000413/LER-1995-003-03, :on 950727,failed to Perform TS Surveillance Due to Unanticipated Interaction of Sys.Reviewed All Penetrations to Determine Whether Similar Situations Exist in Valves Omitted from Containment Integrity Boundary
05000339/LER-1984-003-03, :on 840505,facility Taken off-line to Perform Preventative Maint & Testing on Reactor Trip Breakers.Minor Problems Discovered.Facility Placed Back on-line on 840508
05000339/LER-1995-002-03, :on 950709,missed Surveillance on Individual Rod Position Indication Due to Personnel Error.Returned Both Computer Points D-H2 & D-H8 from Calibr Mode
05000346/LER-1995-001, :on 950126,determined That LOCA Analysis Results for 2 Ft Core Elevation Potentially non-conservative Due to Modeling Errors.Vendor Evaluated Current Fuel Cycle to Determine If Operating Limits Valid
05000259/LER-1984-002-05, :on 840103,setpoint Value of Pressure Switches PS-64-57A-D Found Above Tech Spec 3.2.B. Limits.Caused by Static O-ring Model 12N-AA4 Setpoint Drift.Switches Recalibr.Surveillance Test Revised
05000338/LER-1994-005-02, :on 940909,ESF Actuation Occurred When Main Feedwater Pumps Tripped Due to SG High High Level.Reheat Pressure Transmitter Repaired & Calibrated Satisfactorily & Returned to Svc
05000458/LER-1994-023, :on 940908,reactor Scrammed Due to Spurious Signals from Undamped Rosemount Model 1153 Transmitters. Conditions Leading to Failure Determinded to Be Reportable Per 10CFR21.Model 1153 Transmitters Replaced
05000278/LER-1994-002-01, :on 940203,discovered Main Generator Ground Relay Status Light Out.Caused by Internal Rack Out Tab Not Installed on Alterex Field Breaker.Damaged Component Repaired & Breaker Replaced W/Spare
05000317/LER-1994-003, :on 940321,noticed Leakage from Rcs.Caused by Pwscc.Corrective Action:Sleeve Location B-3 & FF-1 Have Been Plugged W/Alloy 690 Plug Welded to Outer Diameter of Pzr Lower Head
05000440/LER-1990-039, :on 901211,discovered That Both Loops of Containment Spray Mode of RHR Sys Inoperable.Caused by Inadequate Instructions.Instructions Revised to Include Isolation Valve for Position Verification
05000458/LER-1994-004, :on 940113,nonconservative Alarm Setpoint for Liquid Radwaste Gross Activity Monitor 1RMS-RE107.Caused by Personnel Error.Alarm Setpoint for Monitor 1RMS-RE107 Revised to Assure Setpoint Properly Set
05000317/LER-1993-008, :on 931203,determined Removal of EDG Room Shield Door Could Render Other EDGs Inoperable.Caused by Lack of Procedural Controls.Maint Procedure Will Be Generated W/Appropriate Precautions
05000414/LER-1990-010-03, :on 900619,control Room Received Loss of Containment Sample Flow Alarm from Radiation Monitors.Caused by Personnel Error & Lack of Clear Procedure Guidance. Personnel Counseled
05000321/LER-1994-004, :on 940416,discovered That Surveillance Frequency for Sp 34SV-SUV-008-1S Not Correct for Seven Primary Containment Vent & Purge Valves Due to Personnel Error.Surveillance Brought Up to Date
05000482/LER-1991-002, :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
05000424/LER-1990-003-01, :on 900223,discovered 16 Transformer Core Clamp Bolts Missing on Seismically Qualified Switchgear. Caused by Installation Error During Const Phase of Plant. Missing Clamps Replaced
05000296/LER-1988-006-04, :on 881116,compensatory Sampling Required by Tech Specs Erroneously Discontinued.Caused by Procedural Deficiency.Procedures Revised
05000400/LER-1989-002, :on 890117,water Inadvertently Drained from Spent Fuel Pool to New Fuel Pool.Caused by Incorrect Determination of Valves Position During Process of Removing Clearance.Spent Fuel Pool Level Restored
05000316/LER-1990-002, :on 900108,two MSIVs Exhibited Closing Time in Excess of Tech Spec 3.7.1.5 Limit of 5 S.On 900109 & 10, Confirmed That Excessive Condensation Collected on Vent Side.Caused by Inadequate Insulation
05000529/LER-2007-001, Re Completion of a Shutdown Required by Technical Specification 3.5.3, Condition C
05000425/LER-2003-001, Regarding Technical Specification Required Shutdown Not Performed Following Issuance of Notice of Enforcement Discretion
05000318/LER-1998-003-01, :on 980507,relays out-of-calibration Were Noted Due to Bumped Dial & Actions Not Taken.Caused by Improperly Installed Cover.Technicians Will Be Trained on Event & Protective Covers Will Be Clearly Marked
05000382/LER-1987-017, :on 870601,diesel Fuel Oil Analysis Results Not Received within Required Time.Caused by Personnel Transfer at Contract Lab.Individual Responsible for Analysis Not Aware of 7-day Reporting Requirement
05000425/LER-1998-001-04, :on 980308,personnel Noticed Discrepancies Between Demand Position Step Counters & Digital Rod Position Indicators.Caused by Rod Control Firing Card Operating Abnormally.Firing Card Replaced
05000269/LER-1986-013-04, :on 861023,personnel Determined Procedures Used for Operation & Maint of Hydrostation Not Reviewed &/Or Approved Properly.Caused by Mgt/Qa Deficiency.Procedures Program Revised
05000369/LER-1986-007-01, :on 860325,reactor Tripped on Steam Generator Lb lo-lo Level Signal.Caused by Failure of Bussman Fuses. Indicating Fuses Will Be Replaced W/Nonindicating Fuses
05000395/LER-1986-006, :on 860402,turbine Generator Trip Caused Reactor Trip.Caused by Loss of Excitation to Main Generator Due to Worn Brushes on Outboard Collector Ring.Brushes Replaced & Slip Ring Buffed
05000483/LER-1986-022, :on 860621,reactor Trip Occurred as Result of Water Level in Steam Generator D Reaching lo-lo Level Trip Setpoint.Caused by Spurious slow-close Signal Generated by Valve Control Module.Faulty Module Replaced
05000318/LER-1987-002-01, :on 870228,low Steam Generator Water Level Reactor Trip Occurred Due to Failed Rochester Instrument Sys,Inc Adjustable Overshoot Transmitter Lead/Lag Circuit. Cause Under Investigation.Unit Replaced
05000324/LER-1998-002-01, :on 980708,excessive FW Temp Reduction Was Noted as Result of Loss of Stator CW with Main Turbine. Caused by Failure to Analyze Worst Case Lfwh Transient. Process Computer Databank Was Updated.With
05000339/LER-1986-007-01, :on 860416,trip Occurred During Throttle valve- Governor Valve Transfer.Caused by Turbine First Stage Pressure Spike.Investigation of Electro Hydraulic Control Sys Underway
05000382/LER-1985-035, :on 850714,reactor Trip Occurred Due to Electrical Fault in Digital electro-hydraulic Control Panel. Caused by Overheated Resistor on Solid State Circuit Board. Different Resistors Installed
05000317/LER-1995-005, :on 951109,manual Reactor Trip Occurred.Caused by Failure of Digital Feedwater Control Module FIC-1111. Reviewed Design Engineering Standards & Existing FP 2000 Digital Controllers Are Being Replaced
05000281/LER-1984-019-02, :on 841211,reactor Trip Occurred.Caused by Low Condenser Vacuum Due to Leak in Moisture Separator Reheater Crossunder Manway Gasket.Manway Temporarily Sealed,Gasket Replaced & Procedure Revised
05000346/LER-1984-006, :on 840515,unidentified RCS Leakage in Excess of 1 Gpm.Caused by Failure to Perform Surveilance Test on Reactor Protection Sys Shutdown Bypass Channels.Line Permitted to Depressurize Prior to Maint
05000327/LER-1984-072, :on 841207,functional Discrepancy for post- Accident Radiation Monitors for Reactor Coolant Drain Tank Discharge Piping Identified.Caused by Incorrect Drawings. Monitors Revised
05000315/LER-1984-019-01, :on 840818,ability of Turbine Driven Auxiliary Feed Pumps to Meet Safety Function Questioned During NRC Audit.Caused by Governor Setting at 50%.Unit 1 Settings Changed to 85% & Unit 2 to 90%
05000458/LER-1995-007-02, :on 950905,fan Hub for HPCS Pump Room Unit Cooler Failed.Cause Presently Being Investigated.Unit Cooler Repaired & Restored to Operations
05000302/LER-1995-012, :on 950707,determined That CR-3 May Have Operated Outside Licensing Basis.Caused by Design Error.Mod Approval Record Initiated to Install Isolation Contacts in Control Circuits
05000321/LER-1994-012, :on 941025,partial Group 1 PCIS Trip Initiated Because Bias Spring Assembly Incorrectly Installed in Main Turbine EHC Sys.Bias Spring Installed Correctly & Contract Personnel Made Aware of Consequences of Event
05000341/LER-1991-018, :on 911002,discovered Error in TS Amend 75, Resulting in Failure to Complete One of Two Weekly Channel Calibr Requirements for APRM Sys Channels.Caused by Use of Deficient Process.Calibr Performed
05000245/LER-1987-024-01, :on 870715,initiation of Standby Gas Treatment Sys Occurred.Caused by Personnel Error.Lprm Cutting Process Stopped & Detector Lowered Into Spent Fuel Pool.Personnel Counseled Re Lifting LPRM Correctly