05000327/LER-1990-001-01, :on 900108,discovered That Several ERCW Valves Not Being Periodically Verified to Be Correct.Caused by Personnel Error During Procedure Revs & Workplan Reviews. Info Notice Issued to Workplan Reviewers
05000259/LER-1989-004-01, :on 890209,condensate Storage Tank Decreased from 26.7 Ft to 10.1 Ft.Caused by Mechanical Failure of Condensate Head Tank Heat Trace.Heat Trace on Condensate Head Tank Repaired
05000320/LER-1989-005-01, :on 890830,operations Personnel Observed That Voltage of Cell 71 of Station Storage Battery Decreased More than 0.1 Volts Below Baseline Voltage Required by Recovery Operation Plan.Caused by Degradation of Cell
05000338/LER-1989-004-01, :on 890405,determined That One Steam Generator Tube of Initial Sample Group Was Defective During 1989 Refueling Outage.Caused by Primary Water Stress Corrosion Cracking.Tubes Susceptible to Failure Plugged
05000298/LER-1989-021, :on 890602,undocumented Wiring Configurations Associated w/safety-related Equipment Discovered During Implementation of Design Change 87-190.Caused by Existence of Unexpected GE Supplied Subj Configurations
05000280/LER-1988-030, :on 880517,operator Reported That Water Was Flowing Into Loop C Room from Penetration of Reactor Coolant Loop Through Shield Wall.Cause Unknown.Backup Nitrogen Supply Restored to Inflatable Seal
05000324/LER-1989-001-03, :on 890214,momentary Initiation Signal Generated & HPCI Sys auto-started as Designed But Remained in Min Flow Mode & Did Not Inject Into Reactor Pressure Vessel.Caused by Spurious Closure Signal
05000529/LER-1986-017-01, :on 860911,actuation of Reactor Protection Sys Initiated Automatic Reactor Trip.Caused by Effects of Reactor Coolant Pump Speed Transient on Core Protection Calculators (Cpc).Cpc Software Updated
05000369/LER-1987-009-02, :on 870415,reactor Tripped Due to Turbine Tripped Signal Generated While Station Personnel Testing Turbine auto-stop Oil Pressure Switch.Caused by Design Deficiency.Preventive Maint Code Changed
05000298/LER-1986-028, :on 861021,58 Out of 88 Seismic Class Is Supports on Standby Gas Treatment Sys Suction Ductwork Found Structurally Inadequate.Caused by Undocumented Design Changes.Mods Immediately Initiated
05000414/LER-1986-022, :on 860603,feedwater Isolation Occurred Due to Malfunction of Reactor Trip Breaker Control Switch.Operator Update Issued Addressing Proper Method of Manipulating Breaker Control Switches.Switch Will Also Be Replaced
05000327/LER-1999-001-04, :on 990415,exceedance of AOT Occurred Due to Failure of Centrifugal Charging Pump.Rotating Element Was Replaced,Testing Was Completed & Pump Was Returned to Svc
05000366/LER-1998-004-01, :on 981005,noted That full-in Position Indicating Light Did Not Extinguish as Expected When CR 38-15 Was Withdrawn.Caused by Personnel Error.Jumper Was Removed from RPIS Circuit Card for Rod 38-15
05000220/LER-1999-003-01, :on 990320,noted That Plant Operated with Average Planear LHGR Exceeding TS Limits.Caused by Inadequate Interface Design Between Color Graphics Terminal & 3-D Monicore Sys.Lowered Reactor Power.With
05000416/LER-1987-003, :on 870225,both Trains of Standby Gas Treatment Sys Inoperable for 3 H.Caused by Personnel Error.Memorandum Issued to All Plant Personnel Reiterating Need for Attention to Details
05000338/LER-1988-018, :on 880405,channel Check Surveillance for Containment post-accident Pressure Instruments Missed. Caused by Failure to Recognize That Tech Spec 3.3.3.6 Requirements Met.Tech Spec 3.3.3.6 Entered
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
05000245/LER-1985-029, :on 851126,during Bench Checks of Main Steam Safety/Relief Valves,All Six Valves Lifted at Pressures Exceeding Tech Spec Limit.Caused by High Friction at Labyrinth Seal in Valve Topworks
05000302/LER-1997-008, :on 970307,discovered Potential for Possible Pump Failure & Dose Consequences.Caused by Design Errors. Will Keep Plant in Shutdown Until Design Deficiencies Are Resolved & Will Initiate Plant Modification
05000370/LER-1985-025-02, :on 851022,discovered That Encl to Procedure, Quarterly Surveillance Items Re Refueling Canal Drains Not Completed by 851018 Per Tech Spec 4.4.4.2.Caused by Personnel Error
05000281/LER-1985-003, :on 850423,outside Recirculation Spray Pump a Suction Valve Found Degraded & Pump B Valve Found Inoperable.Caused by Inadequate Sector Gear & Sheared Pins in Extension Shafts.Pins Replaced
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
05000454/LER-1997-001-04, :on 970131,failed to Perform Surveillance on Testing on Hydrostatic on Dg.Caused by Inadequate Tracking Mechanism.Developed & Executed Special Surveillance Procedures & Will Enhance TS Interpretation
05000237/LER-1985-031-03, :on 850727,east Bank Scram Discharge Vol hi-hi Water Level Scram Occurred.Caused by Steam Generated from Reactor Bldg Drain Header.Trip Setpoint of Instruments Lowered & Engineering Analysis Performed
05000388/LER-1985-021-01, :on 850630,neutral Overvoltage Occurred in Main Generator,Causing Primary Lockout.Caused by Failure of Phase C Main Transformer Low Voltage Bushing.Bushing Replaced W/Spare Component
05000461/LER-1996-018, :on 961014,incorrect Torque Value for Control Rod Drive Hydraulic Control Units Was Specified by Supplier. Caused by Lack of Attention to Detail.All Hold Down Bolts on CRD HCUs Were Replaced
05000346/LER-1984-021, :on 841220,Q-listed & Seismic Class I Ductwork &/Or Ductwork Supports Spanned Bldg Seismic Isolation Boundaries.Caused by Differential Movement Not Factored in Design of Ductwork Sys
05000298/LER-1985-001, :on 840922,during Secondary Containment Leak Test,Fuel Handling Operations Conducted W/O Verification of Secondary Containment Integrity.Caused by Combination of Procedural & Personnel Errors
05000354/LER-1995-016, :on 950708-09,SDC Bypass Event Occurred, Rendering SDC Mode of RHR Sys Inoperable Due to Procedural non-compliance & Inadequate Operator Knowledge,Skills & Training.Special Training on Event Conducted
05000416/LER-1992-007, :on 920511,determined That TOL Settings for Certain Motors May Not Be Conservative for Extended Operation Undervoltage Conditions.Caused by Applied Voltage. TOL Settings Were Optimized
05000334/LER-1984-009, :on 840706,Smoke Detection Instrumentation Test Ost 1.33.16 Found Only Partially Completed,Since Containment Smoke Detectors Not Tested.Caused by Inadequate Procedure Review.Administrative Procedures Revised
05000456/LER-1995-013-04, :on 951012,fire Protection App R Design Discrepancies Occurred Due to Inadequate Evaluations During Preparation of Original Analysis.Maintained Hourly Fire Watches for All Fire Zones
05000287/LER-1984-005-03, :on 840814,trip Occurred When Instrument Air Line to Powdex Outlet Valves Accidentally Sheared.Caused by Attempt to Straighten Bend Which Resulted from Work on Pipe Above Instrument Air Line
05000338/LER-1992-005, :on 920113,timers Drifted Outside Setpoint Tolerance Listed,Per Tech Spec Table 4.8-1.Caused by Setpoint Drift.Timers Reset & Successfully Retested.W/
05000269/LER-1984-001-04, :on 840301,boron Concentrations of Two Independent Core Flood Tank 1A Samples Less than Tech Spec Requirements.Caused by Lack of Adequate Mgt Control Over Known Problem.Procedures Revised
05000327/LER-1984-021, :on 840322,spent Fuel Pit High Radiation Alarm Actuated,Which Caused Auxiliary Bldg Isolation to Occur. Caused by Movement of Contaminated C-zone Clothing & Trash. Alarm Cleared & Monitor Returned to Svc
05000269/LER-1994-005-03, :on 941005,containment Isolation Valve 1RC-7 Rendered Technically Inoperable Due to Change Mgt.Valves 1RC-5 & 6 Closed & Electrically Deactivated & Mechanical Maint Team Involved Counseled
05000445/LER-1990-023, :on 900808,reactor Tripped on Loss of Feedwater Flow.Caused by Loose Fuse in Main Feedwater Control Power Circuit.Corrective Maint Performed on Malfunctioning Fuse Clip
05000445/LER-1990-019, :on 900726,source Range Flux Doubling Actuation Occurred Due to Spurious Source Range Signal Decrease.Cause Not Identified.Operation & Troubleshooting of Channel SR N32 Observed Indicating Correct Functioning
05000445/LER-1990-017, :on 900527,main Feedwater Flow Control Valve Failed Closed,Resulting in Reduced Feedwater Flow & Decreasing Steam Generator Water Level.Caused by Failure of Solenoid Valve Coil.Solenoid Coil Replaced
05000482/LER-1990-008, :on 900504,fuel Bldg/Control Room Ventilation Isolation Signals Received from Exhaust Radiation Monitor. Caused by Burned Out Lamp & Blown Fuse in Power Supply.Fuse & Lamp Replaced & Monitor Returned to Svc
05000445/LER-1990-013, :on 900509,while Installing Jumpers Across Feedwater Pump Speed Controllers,Pump Coastdown Occurred, Resulting in Loss of Feedwater Flow & Reactor Trip.Caused by Inadequate Procedure Review.Review Performed
05000285/LER-1989-020, :on 891012,determined That Two of Four Component Cooling Water HXs Simultaneously Inoperable for More than 24 H.Caused by Inadequate Controls Re Return of Equipment to Svc.Standing Order Revised
05000336/LER-1984-003, :on 840103,safety Injection Tanks 2 & 3 Fell Below Min Level.During Filling,Valves Closed.Caused by Residual Water Collected in Dry Ref Legs.Tanks Lowered,Legs Drained & Instruments Calibr
05000298/LER-1987-005, :on 870110,while Primary Containment Inerting in Progress,Reactor Scram Occurred Due to Closure of Msivs. Caused by Inadequate Procedural Guidance.Operating Alarm Procedures Will Be Revised