05000410/LER-1988-014, :on 880313,reactor Scram & ESF Actuations Occurred.Caused by Equipment Failure Due to Design Deficiency.Transmitter Replaced W/Upgraded Model & Temporary Mod Performed to Bypass Logic for Valves
05000259/LER-1987-006-01, :on 870302,discovered That Routine Flow Rate Surveillance on Control Room Emergency Ventilation Train B Performed Incorrectly on 870301.Caused by Personnel Error. Correct Zeroing Procedure Clarified
05000311/LER-1996-016-02, :on 961220,missed Surveillance for Determining Response Time of High Containment Gaseous Radioactivity ESF Actuation Occurred.Caused by Inadequate Implementation of TS Requirements.Procedures Will Be Revised
05000311/LER-1996-014-03, :on 961201,EDG Automatic Start Resulted in ESF Actuation.Caused by Defective anti-pump Relay in 23 Csd Vital Infeed Breaker.Defective anti-pump Relay Identified
05000255/LER-1995-005-01, :on 950721,received Two Inadvertent SISs While Performing TS Test RO-12.Caused by Two Wires Taped Together After Being Removed from Terminal in Attempt to Isolate Sis. Procedure RO-12 Revised
05000255/LER-1995-004-01, :on 950714,determined That Redundant DG Circuits Not Separated Per App R Due to Insufficient App R Program Documentation.Hourly Fire Tour Established in EDG 1-1 Room & Review of LERs for App R Completed
05000255/LER-1994-012-01, :on 940427,w/plant in Cold Shutdown,Determined That Internal Ground in Thermal Margin Monitor Caused Nonconformance W/Rps Design Basis.Mod Implemented to Effectively Isolate Grounded Monitor from Pressure Loop
05000255/LER-1994-019, :on 941109,identified Failure to Test Redundant Equipment Per TS 3.3.2.f Prior Ro Removal of Electrical Breakers from Svc for Planned PM Due to Personnel Error. Administrative Procedure 5.14 Revised
05000255/LER-1994-017, :on 940902,EDG 1-1 Degraded Load Carrying Capability Identified.Caused by Inadequate Design Basis, Failure to Effectively Monitor for Engine Performance Degradation & Failure to Control Mods
05000255/LER-1994-008, :on 940329,30 & 0409,discovered That Some Class 1E Circuits Not Isolated or Separated from non-Class 1E Circuits Due to Lack of Engineering Design Guides.Subj Deviations Corrected W/Exception of CETs
05000255/LER-1994-013, :on 940427,unsupported RCP Instrument Tubing Identified as Being Outside of Plant Design Basis Due to Lack of Supports.Tubing Supports Installed & Now Conforms to Spec Criteria
05000255/LER-1994-006, :on 940217,plant Shutdown Per TSs Due to Leak on Asme,Section Xi,Class 2 saftey-related Check Valve. Caused by Through Wall Defect on Valve CK-ES3166.Check Valves CK-ES3166 & CK-ES3188 Replaced
05000255/LER-1994-002, :on 940126,inadvertent Containment Spray Pump ESF Actuation Occurred During Performance of TS Surveillance Testing.Caused by Inadequate Procedure.Tssp Q0-1 Modified to Warn Operators of CSP Start
05000255/LER-1993-004, :on 930630,fuel Rod Failed & Loss of SNM Discovered Following Refueling Operations.Caused by Core Shroud & Fuel Assembly Interface Problem.Fuel Assembly Insps Increased & Failed Fuel Response Plan Implemented
05000255/LER-1993-006-01, :on 930804,determined That Reg Guide 1.97, Category 1,pressurizer Level Indicator Powered from non- Safety Related Power Supply.Caused by Personnel Error. Indicator LIA-0102A Powered from Ac Source
05000255/LER-1993-005-01, :on 930720,both EDGs Started After Receiving Undervoltage Signal Due to de-energization of Electrical Bus 1C.Caused by Inadequate Design Info.Sys Engineers Will Be Trained on Event
05000280/LER-1989-016, :on 890423,inadvertent Positive Reactivity Addition by Boron Dilution Occurred W/O Containment Integrity in Tact.Caused by Leakage Due to Improper Adjustment of Valve Operator Travel Stops
05000529/LER-1989-005, :on 890310,loss of Power to Alternate Plant Ventilation Effluent Radiation Monitor Occurred.Caused by Electrical Loads in Excess of Circuit Capacity.Power Restored to Alternate Sampling Sys
05000311/LER-1996-005-02, :on 960627,surveillance of Fuel Handling Bldg Ventilation Sys Charcoal Adsorber Test Was Missed.Caused by Inattention to Detail.Individual Involved Received Appropriate Level of Positive Discipline
05000280/LER-1988-017, :on 880606,foreign Matl Found in Temporary Discharge Cone Strainer & Deficiencies Found in Sump Screens.Caused by Inadequate Insp Program During Const Activities.Foreign Objects Removed
05000272/LER-1996-005-03, :on 960325,TS Surveillance Requirement Implementation Deficiencies Identified.Caused by Lack of Adequate Controls & Understanding of Development Weakness. Procedures Revised
05000364/LER-2023-003, Pressurizer Code Safety Valve Lift Pressure Outside of Technical Specifications Limits
05000334/LER-1989-006-01, :on 890513,discovered That Pump Not Placed on Increased Frequency Testing in Accordance W/Inservice Testing Program.Caused by Typo on Data Sheet Used to Record Pump Vibration Data.Typo Corrected
05000382/LER-1998-013, :on 980701,IST Valve Surveillances Were Missed. Caused by Inadequate Processing of Info Transferred Between Operations Procedure Group & Programs Engineering.Procedure Revised
05000382/LER-1998-011, :on 980603,TS 3.0.3 Entry Was Noted.Caused by Component Cooling Water Makeup Check Valve Failing Ist. Operability of a Train of CCW Was Restored Immediately & Check Valve Internals Were Replaced
05000382/LER-1999-010-01, :on 990726,discovered Inadequate Pumping Capacity in Dry Cooling Tower Area.Caused by Inadequate Design Control.Portable Pumps Were Installed in Each Dry Cooling Tower Areas to Ensure Sufficient Pumping Capacity
05000529/LER-1986-039-01, :on 860903,control Room Essential Filtration Actuation Signal (CREFAS) Generated After CREFAS Module Removed from Bypass Before All Trip Inputs Cleared. Appropriate Disciplinary Action Taken
05000281/LER-1986-017-02, :on 861121,during Periodic Test 8.5A, Inadvertent Auto Start of Emergency Diesel Generator 3 (EIIS-ER) Occurred.Caused by Personnel Error.Testing Suspended & Diesel Shut Down
05000382/LER-1999-005-01, :on 980702,determined That Four Contacts in Control Circuits of EFW Control Valves Were Untested.Caused by Personnel Error.Untested Contacts Have Been Tested
05000263/LER-1998-005-01, :on 980921,HPCI Was Removed from Service to Repair Steam Leak in Drain Trap by Pass.Caused by Localized Erosion of Valve Body.Valve Was Declared Inoperable & Was Replaced with Manual Valve
05000250/LER-1998-005-02, :on 980924,suspended Safeguards During Severe Weather Due to Personnel Safety.Caused by Severe Weather Associated with Effects of Hurricane Georges.Fully Instituted Compensatory Measure.With
05000289/LER-1998-010-01, :on 980825,potential Violation of Design Criteria During Single Auxiliary Transformer Operation Occurred.Caused by Failure to Adequately Define Job Performance Stds.Temporary Change Notice Issued
05000382/LER-1997-018, :on 970428,voluntary LER for Dropped New Fuel Assembly Was Issued.Caused by Human Error.Sfhm Grappling Tool Was Inspected for Damage or Misalignment
05000321/LER-1985-034, :on 851014,plant Personnel Received RWCU Isolation When Pump Inboard & Outboard Isolation Valves Isolated on High Differential.Caused by Intermittent Spiking Flow Transmitter
05000354/LER-1996-026-01, :on 961108,ESF Actuation/Single Rod Scram Occurred Due to Stuck Scram Solenoid Pilot.Sspv Replaced & CR 42-07 Returned to Svc
05000302/LER-1996-024, :on 961011,plant Mod Created Unanalyzed Condition Re Emergency Feedwater Availability.Caused by Inadequate Translation of Assumptions from Earlier Designs. Design Basis Documents Were Corrected
05000266/LER-1997-004, :on 970113,potential for Particular Common Mode Failure That Could Affect Opposite Trains of Unit 2 Safeguards Equipment Was Noted.Caused by Lack of Physical Separation.Replaced Subject Circuit Breakers
05000266/LER-1997-001, :on 970108,safety Injection Delay Times Exceeded Design Basis Values.Caused by Degraded Voltage Conditions.Licensee Engineers Will Prepare FSAR Change Requests to Reflect LBLOCA Evaluation
05000309/LER-1996-031, :on 961009,plant Trip During Reactor Protection Sys Surveillance Occurred.Cause Has Not Been Determined.Ac Logic Matrix Components Were Undergoing Testing at Time of Trip Were Replaced
05000461/LER-1997-001, :on 970103,nuclear Fuel Supplier Failed to Analyze Turbine Pressure Regulator Downscale Failure Event in off-rated Condition Per 10CFR21.21.Caused by Error in Nuclear Fuel Supplier.Mcpr Will Be Implemented
05000282/LER-1996-019, :on 961127,spent Fuel Storage Racks Outside Design Basis Due to Boraflex Degradation.Boric Acid Has Been Placed in Immediate Vicinity of Spent Fuel Pool in Event Manual Addition Is Required
05000382/LER-1996-011-01, :on 960820,CR Normal Ventilation Isolation Valves (HVC-101 & HVC-102) Were Leaking.Caused by Debris Which Accumulated Inside Valves Disc Regions.Valves Were Closed
05000382/LER-1996-009-01, :on 960725,failure of Containment Vacuum Relief Valves CVR-402A & CVR-402B Occurred.Caused by Excessive Roughness in Valve Body Bore.Valves Replaced & Retested
05000321/LER-1996-010, :on 960629,failure of Turbine Overspeed Control Valve Occurred.Caused by Failed Hydraulic Actuator Diaphragm.Replaced Failed Diaphragm & HPCI Control Valve Diaphragm
05000382/LER-1996-013-01, :on 960822,possible Operation in Excess of 100% Licensed Power.Cause Is Being Investigated
05000382/LER-1996-007-01, :on 960411,discovered That Design Basis Flow Rates Could Not Be Achieved on Auxiliary Component Cooling Water Sys.Caused by Inadequate Design.Modified Sys Design & Reviewed Other safety-related Fluid Systems
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
05000369/LER-1985-004-01, :on 850128,reactor Tripped on lo-lo Steam Generator Level When Main Feedwater Pump Tripped on Low Suction Pressure Signal.Caused by Failure of Pneumatic Pressure Transmitter.Components Replaced
05000382/LER-1996-003-01, :on 960130,logarithmic Power Channels Indicated 5 Percent of Scale Below Actual Power.Caused by Not Periodically cross-correlating Log Power to Linear Power. Recalibrated Log Power Channels
05000317/LER-1995-005-01, :on 951109,manual Reactor Trip Occurred Due to Increasing SG 11 Water Level.Caused by Failure of Digital Control Module FIC-1111.Controller Sent to Vendor for Troubleshooting & Root Cause Analysis
05000369/LER-1984-023, :on 840723,unit Tripped from 100% Power on lo-lo Steam Generator Level Indication.Caused by Feedwater Sys Solenoid Valve Failure.Chart Recorder Added to Feedwater Valves by Hydraulic Pump Motor
05000354/LER-1995-027, :on 951027,grab Sample Not Taken within Required 8 Hour Period.Caused by Equipment Failure Resulting in 12 Hour Hot Shutdown.Investigation & Repair of Equipment Failures Initiated
05000289/LER-1995-005-01, :on 951012,invalid Heat Sink Protection Sys Actuation Occurred.Caused by Failure of Logic Modules.Logic Module Failure Analysis Will Continue in Order to Substantiate Suspected Failure Mode
05000362/LER-1984-023-01, :on 840601 & 11,during Turbine Overspeed Protection Test,Reactor Trip Occurred Involving RCS Specific Activity.Caused by Iodine Spiking.Primary Coolant Activity Will Be Monitored & Evaluated
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
05000285/LER-1994-001, :on 940211,safeguards Actuation & Reactor Trip Occurred Due to Relay Failure.Containment Pressure High Signal Relay Replaced & Sent for Investigation of Failure Mechanism
05000366/LER-2019-001, Emergency Diesel Generator Valid Actuation Signal Due to Inadvertent Electrical Bus De-Enerqization
05000280/LER-1991-012-01, :on 910720,discovered That Pressurizer Level Channel Not Declared Inoperable,Per Acceptance Criteria Due to Personnel Error.Personnel Involved Reinstructed in Review of Recorded Data & Supervision of Trainees
05000280/LER-1992-003, :on 920214,determined That Certain ESF Sys Logic Acutation Relays Not Fully Tested Per Ts.Caused by Inadequate Testing Methodology.Surveillance Procedures for Channel Functional Test Changed
05000280/LER-1990-018, :on 901203,unplanned Initiation of ESF & SI Occurred During Performance of Operations Periodic Test. Caused by Inadequate Test Procedure.Personnel Preparing & Reviewing Test Procedures Will Be Cautioned
05000281/LER-1990-001-01, :on 900108,one of Three RCS Average Temp Channel Inputs to Reactor Protection Sys Not Declared Inoperable After Deviating from Other Two Channels.Caused by Faulty Summator.Summator Replaced
05000280/LER-1989-038, :on 890903,emergency Diesel Generator 3 Started When Control Switch Was Placed from Exercise to Auto Position During Shutdown Attempt.Caused by hi-hi Consequence Limiting Safeguards Signal.Procedures Revised
05000281/LER-1989-011-02, :on 890919,found That Pipe Support Rigidly Attached to Auxiliary Bldg Structure & Facility Containment Which Violates Design Requirements.Caused by Design Error. Pipe Support Modified
05000281/LER-1988-002, :on 880202,determined That Individual Valve Leakage Through Reactor Coolant Cold Leg Sample Isolation Valves Was Greater than ASME Section XI Spec.Caused by Impurities in Sys.Valves Replaced
05000280/LER-1989-004, :on 890215,determined That Cable Tray Covers Did Not Comply W/App R Commitments Since Min Cable Separation Did Not Meet Reg Guide 1.75 Requirements.Caused by Improper Installation & Reinstallation
05000280/LER-1989-007, :on 890302,planned ESF Actuation Resulted in Lockout of Ventilation Vent Radiation Monitor Sample Pump & Alternate Sampling Not Initiated.Caused by Personnel Error. Auxiliary Ventilation Emergency Mode Reset
05000281/LER-1988-020-01, :on 880909,individual Rod Position Indicators for Four Control Rods of Control Bank D Differed from Demand Counter by More than 12 Steps.Caused by Indicator Indication Drift.Indicators Adjusted
05000280/LER-1988-034, :on 881203 & 14,main Control Room C & Emergency Switchgear Room Chiller Tripped.Caused by Insufficient Water Flow to Chiller C & Lack of Calibr on Chiller Condenser Pressure Control Valves.Valves Adjusted
05000280/LER-1988-021, :on 880728,PORV Cycled Open & Then Closed. Caused by Overly Conservative Setpoint.Setpoint Changed
05000281/LER-1988-025-02, :on 881208,determined That Power Supplies for Two Safety Injection Valve Operators Reversed.Caused by Error During Initial Plant Const.Engineering Work Request Issued to Correct as-found Conditions
05000281/LER-1995-003, :on 950224, as Found Calibration Test Data for Three RPS Transmitters Not within Allowable Tolerance. Caused by Faulty Pressure Gauge Used in Calibration.Pressure Gauge Replaced & Repeated Calibration Check
05000280/LER-1989-005, :on 890204,auto Start of Emergency Diesel Generators 1 & 3 Occurred Upon Loss of Transfer Bus F.Caused by 4,160-volt Supply Circuit Breaker Failure.Circuit Breaker Cleaned & Tested Satisfactory
05000280/LER-1995-008, :on 950919,pressurizer Safety Valve Found Setpoint Out of Tolerance.Caused by Psvs Being Installed Prior to Start of Most Recent Operating Cycle
05000280/LER-1996-001, :on 951213,ESW Pump Was Inoperable Due to Loss of Missile Protection for Piping.Revised DCP 91-025
05000281/LER-1988-022-01, :on 880910,reactor Trip by Turbine Trip Occurred While Attempting to Maintain Turbine at Synchronous Speed.Caused by Inadequate Procedure & Faulty Valve Position Indication.Testing to Be Performed
05000281/LER-1988-017-02, :on 880730,failure of Recirculation Spray Svc Water MOVs Due to Premature Actuation of Torque Switch. Both Valves Declared Inoperable & Tech Spec 3.0.1 Entered on Basis That Both Subsystems Were Inoperable
05000280/LER-1988-011-01, :on 880415,power-operated Relief Valves Failed to Manually Open When Selector Switches Placed in Open Position.Cause Under Investigation.Selector Switches,Air Supply & Valves Examined for Malfunctions
05000280/LER-1988-012-01, :on 880418,Tech Spec 1.0.H.5 Violated.Caused by Discovery of Valve 1-RS-11 Held in Open Position by Counter Weight Due to Personnel Error.Valves Inspected & Verified to Be in Closed Position & 1-RS-11 Disassembled
05000280/LER-1988-023, :on 880802,C Steam Generator Channel IV Steam Flow Failed to Low Flow Indication.Caused by Failed Multiplier/Divider Unit Power Supply Transformer.Technicians Called in & Placed Channels in Trip Mode
05000280/LER-1988-006-01, :on 880219,individual Rod Position Indicators Differed from Rod Group Demand Counter by Greater than 12 Steps.Caused by Generic Westinghouse PWR Concern.Rods Calibr to Give Correct Indication & Returned to Svc
05000280/LER-1988-025, :on 880815,control/relay Room Chillers Inoperable.Caused by Inadequate Svc Water Flow to Chiller Condensers as Result of Method to Start/Stop Chillers.Addl Procedure Will Be Developed
05000280/LER-1987-028, :on 871021,reported That Emergency Diesel Generators Output Breaker Protection Circuits Contained Instantaneous Overcurrent Tripping Relays.Caused by Design Deficiency.Trip Relay Settings Increased
05000281/LER-1988-004, :on 880327,turbine Runback Automatically Initiated Due to Loss of Power to Power Range Nuclear Instrument NI-43.Caused by Internal Conductor Failure Due to Age.Vital Bus Inverters Replaced
05000280/LER-1987-024, :on 870920,RCS Flow Reactor Trip Occurred When Reactor Coolant Pump B Tripped.Caused by Complete Separation of Phase Main Load Connection Bus Bar A.Failed Bus Bar Replaced & Other Bus Bars Inspected
05000280/LER-1987-012-01, :on 870607,recirculation Spray Pump Declared Inoperable Due to High Vibrations.Caused by Threaded Nut & Bolt Detached & Located in Impeller Region of Pump.Loose Nut & Bolt Removed & Pump Realigned
05000280/LER-1987-013-01, :on 870623,unit Shutdown Commenced Due to High RCS Leak Rate.Caused by Failed Packing on Loop Stop Valve MOV-1593.Loop Stop Valves Repacked & Diaphragm on Drain Header Isolation Valve Replaced
05000272/LER-1996-036, :on 961106,28 Volt Dc Battery Capacity Was Exceeded.Caused by Inattention to Detail.Replaced Lamps Installed in CR Console push-button Stations
05000272/LER-1997-001-02, :on 970117,discovered Inadequate IST Surveillance of B Injection Inlet Valves.Caused by Inadequate Communication Between EOP & Ist.Reviewed Salem EOPs for Similar Problems
05000311/LER-1996-015-02, :on 961219,breach of Containment Closure During Core Reload Occurred.Caused by Inadequate Inplementation of Outage Scheduling & Risk Management Requirements.Containment Closure Was Reestablished Using Alternate Isolation Poi
05000272/LER-1996-040, :on 961223,buffer Relays Omitted from TS Required Response Time Surveillance Tests.Caused by Inadequate Implementation of TS Requirements.Revised Response Procedures
05000272/LER-1996-041, :on 961228,surveillance for Radiation Monitors Source Check Required by TS Was Missed.Caused by Lack of Attention to Detail.Reemphasized Mgt Expectations Concerning Surveillance Test Accountability
05000272/LER-1996-011-02, :on 960620,pressurizer Safety Relief Valves Were Found Outside of TS Tolerance.Caused by Minor Testing Instrument Error.Valves Were Refurbished & Successfully Retested to within TS Tolerance
05000311/LER-1996-010-02, :on 960819,TS 4.0.5 Surveillance for Two Pressurizer Welds Was Missed Due to Insufficient Verification & Validation of Entry of Data Into Database. Exam of Pressurizer Spray Nozzle Was Completed
05000272/LER-1996-017-01, :on 960725,surveillance Was Missed for Plant Vent.Caused by Personnel Error.Lco Compensatory Action Was Immediately Completed Upon Discovery of Missed TS Requirement
05000272/LER-1996-004-01, :on 960307,surveillance Was Missed for Salem Generating Station.Caused by Lack of Adequate Control for Development & Maintenance of TS Surveillance Procedures. License Change Will Be Submitted
05000272/LER-1996-018-01, :on 960719,potential Performance Impact on ECCS Identified Involving non-safety Related Refueling Water Storage Tank Piping.Caused by Design Discrepancy.Design Reviewed & Revised
05000272/LER-1995-024, :on 950911,determined Fuel Handling Bldg Low Differential Pressure Surveillance Testing Did Not Ensure Compliance W/Ts Requirements.Caused by Inadequate Design Basis Info.Fuel Handling Bldg Changed
05000255/LER-1994-012, :on 940427,determined That Internal Ground in Thermal Margin Monitor Causes Nonconformance W/Rps Design Basis.Incorporated RPS Failure Modes & Effects Analysis in Plant DBD
05000255/LER-1996-004, :on 960118,SIS Disabled W/Primary Coolant Sys Greater than 300 F.Caused by Personnel Error.Permanent Maint Procedure to Disable/Enable SIS Actuation on Low Pressurizer Pressure Will Be Revised to Align W/Ts
05000255/LER-1995-012, :on 950701,discovered Unqualified Electrical Connection in Containment SW Outlet Valve Controller.Caused by Failure of Assigned Engineers to Available Info.Replaced Wire Nuts W/Inline Butt Connections
05000255/LER-1995-007, :on 950720,discovered That 12 Instrument Loops Had V-bolted Type Qualified Cable Splices Connected to Wires W/Exposed Kapton Insulation.Caused by Human Error.All V- Bolted Splices Replaced w/in-line Design
05000255/LER-1995-003-01, :on 950522,main FW Pump Transient Resulted in Rt.Evaluated MFP Governor Control Setpoint of 5250 RPM & Relationship to Overspeed Trip Setpoint
05000255/LER-1995-006, :on 950629,determined That AFW Pump Low Suction Pressure Trip Setpoints Inadequate Due to Failure of Design of Afws Suction Piping to Consider Suction Vortexing.Rev of Low Suction Pressure Trip Setpoints Made
05000255/LER-1995-001-01, :on 950302,left Channel DBA Sequencer Malfunctioned & Started Most of Left Channel Safeguards Equipment.Caused by Failure of DBA Sequencer micro-processor Module.Svc of Mfg of Sequencer Hardware Will Be Utilized
05000255/LER-1995-002-01, :on 950307,degraded Sealing Capability of Inner Door of Personnel Air Lock Discovered.Caused by Personnel Error.Need to Establish Teamwork & Anticipate Plan for Contingencies Discussed
05000255/LER-1993-007, :on 930817,dark Debris Cloud Observed in SFP Around Edges of Boraflex Surveillance Coupon.Caused by Flow Induced Deterioration of Full Length Coupons Due to Inadequate Holding Canister.Neutron Attenuation Tests Done
05000255/LER-1995-009, :on 950728,discovered Lack of Procedural Guidance for Pump Repair Following Fire.Proposed Use of Power Supply Breaker Did Not Adequately Address Effect of Loss of Control Power.Performed Independent Assessment
05000255/LER-1994-004, :on 940209,ESS Pump Cooling Failed. Caused by Failure to Recognize That Ess Pumps Dependent on Seal & Bearing Cooling.Revised Plant Operating Procedures So Normal Position for CV-0913 & CV-0950 Open
05000255/LER-1994-018, :on 941026,failure to Properly Implement TS 4.7.1.C,EDG Refueling Outage Insps Occurred.Caused by Failure to Maintain Adequate TS Basis Documents.Formal Evaluation of Recommended Insps Initiated
05000225/LER-1994-003, :on 940203,position Switches for Containment Air Cooler Svc Inlet & Valves Not Qualified for Submergence. Caused by Master Equipment List Which Did Not Alert User of Existence of Qualification Restrictions
05000255/LER-1994-003-01, :on 940209,discovered That Single Active Failure Could Disable Seal Cooling to Ess Pumps & Backup Cooling Supply Not Fully Qualified.Affected Valves Opened to Eliminate Possibility of Single Failure
05000255/LER-1992-031, :on 920402,left Channel DBA Sequencer Inadvertently Activated by Technician Preparing to Test Left Normal Shutdown Sequencer Due to Inadequate Test Procedures. Procedures RT-13A & B & RT-8C & D Revised
05000255/LER-1993-005, :on 930720,discovered Both Emregency Diesel Generators Started After Receiving Undervoltage Signal Due to de-energization of Electrical Bus 1C.Caused by Lack of Vendor Information.Procedures Revised
05000255/LER-1994-001, :on 940121,both Trains of Control Room Emergency Heating,Ventilation & Air Conditioning Inoperable. Caused by Screen Plugged W/Ice & Snow.Surveillance Procedure Revised
05000255/LER-1993-007-01, :on 930817,degradation of Boraflex Neutron Absorber in Surveillance Coupons Observed.Cause of Event Unknown.Temporary Requirement for Daily Sampling & Analysis of SFP Boron Discontinued
05000255/LER-1993-012, :on 931103,concluded That Seismic Qualification Did Not Exist for Relays Previously Installed in Chp & Chr Circuits Due to Undersized Relay Coils.Undersized Coils in Relays Replaced
05000255/LER-1992-028, :on 920331,potential Inability to Maintain Diesel Generator Room Temp Qualification Due to non-1E Qualified Cooling Fan Noted.Procedures Revised & Design Will Be Corrected
05000255/LER-1993-003, :on 930428,unusual Event Declared & Plant Shutdown Commenced Due to Primary Coolant Sys Unidentified Leakage in Excess of Ts.Leaking CRDM Mechanical Seal Packages Repaired
05000255/LER-1992-038, :on 920825,reactor Tripped,Resulting from Loss of Preferred Ac Bus Y-20,coincident W/Blown Fuse in Second Channel of Rps.Caused by Failure of Inverter ED-07.All Fuses Checked & Plant Drawings/Vendor Manuals Updated
05000255/LER-1992-039, :on 921030,reactor Automatically Tripped Due to Loss of Load Resulting from Unstable Voltage to Turbine Control Sys Computers.Caused by Failure to Maintain Power Voltage to Ups.New Transformers Installed
05000255/LER-1992-034, :on 920701,reactor Automatically Tripped on Loss of Load Signal,Resulting in Turbine Generator Trip & Loss of Signal.Caused by Momentary Loss of Power to Turbine Sys computers.Post-trip Review Completed
05000255/LER-1992-036, :on 920802,during Monthly TS Procedure for 1-1 Edg,Noted That Exhaust Temp Indicated Low Reading.Caused by Lack of Adequate Controls in DG Cylinder Latch.Edg Test Procedures Will Be Revised
05000255/LER-1992-035, :on 920724,reactor Tripped Due to Loss of Turbine Digital Electrohydraulic Control Sys.Caused by Momentary Loss of Power to Electrohydraulic Sys Computers. Power Supply Switching Circuits Replaced
05000255/LER-1992-017, :on 920229,unusual Event Declared When Upper Guide Structure Raised for Removal from Reactor Vessel & Fuel Assembly Observed Hanging from Structure.Caused by Bent Fuel Alignment Pins.Pins Straightened
05000255/LER-1993-001-01, :on 930106,EDG 1-1 & 1-2 Simultaneously Inoperable When Overspeed Trip Device for DG 1-1 Tripped. Caused by Personnel Failing to Follow Switching & Tagging Order.Overspeed Trip Devices Labeled
05000255/LER-1992-033, :on 920414,inoperable Control Room Penetration Occurred.Caused by Misapplication of Procedures & Inaccurate Procedures.Plant Administrative Procedure on Control of Equipment Status Will Be Updated
05000255/LER-1992-037, :on 920814,reactor Tripped Due to Low SG Level Resulting from Broken Air Line on Main Feedwater Regulating Valve.Air Lines to Main Feedwater Regulating Valves CV-0701 & CV-0703 Replaced & Satisfactorily Tested
05000255/LER-1988-004, :on 880303,required Dissolved Oxygen Analysis Not Completed.Caused by Personnel Error.Data Sheets Revised to Clearly Identify Analyses Required by Tech Specs & Required Time to Be Completed
05000255/LER-1988-008, :on 880512,containment Penetration Declared Inoperable Due to Failure to Complete Required Local Leak Rate Test within Prescribed Time Limitation.Caused by Data Entry Error.Test Schedule Verified
05000412/LER-1989-003, :on 890212,noticed Erratic Operation of Main Feedwater Regulating Valve C & Turbine Trip/Reactor Trip Occurred Due to High Water Level in Steam Generator C.Caused by Valve Vibration & Hydraulic Forces
05000296/LER-1997-003-01, :on 970314,Unit 3 Main Steam SRVs Pilot Cartridges Failed Setpoint Tolerance Bench Tests.Caused by Corrosion Bonding of SRV Pilot Disc/Seat Interface Resulting in Drifting.Main Steam SRV Pilot Replaced
05000410/LER-1989-014, :on 890413,unit Reactor Experienced Reactor Scram Which Was Result of Turbine Trip Due to Actuation of Generator Protection Circuitry.Turbine Trip Caused by Disconnected Wire.Wire Relanded
05000296/LER-1989-001-03, :on 890209,failure to Provide Required Continuous Fire Watch on Inoperable Fire Doors,Per Tech Spec 3.11.E.Caused by Insufficient Training of Fire Protection Personnel.Corrective Maint Initiated
05000296/LER-1988-007-04, :on 880929,diesel Generator 3C Overheated Due to Inadvertent Isolation of Emergency Equipment Cooling Water.Caused by Valve Misalignment & Error in Flow Diagrams.Surveillance Instruction Revised
05000296/LER-1989-003, :on 890307,unplanned ESF Actuations Occurred. Caused by Voltage Transient Due to Start of Control Bay Chiller 3B Because of Design of Circuit Protectors Being Sensitive to Minor Electrical Disturbances
05000296/LER-1988-016-02, :on 880320,offgas Sys Stack Flow Monitor Inoperable & Flow Rate Monitored Every 6 H Instead of 4 H in Violation of Tech Specs.Caused by Personnel Error.Flow Recording Initiated Every 4 H
05000296/LER-1989-002-03, :on 890307,discovered That Compensatory Reactor Coolant Water Sampling Not Performed W/Continuous Conductivity Monitor Inoperable as Required by Tech Specs. Caused by Procedural Deficiencies
05000400/LER-1987-044, :on 870713,Tech Spec Surveillance for Axial Flux Difference Missed.Caused by Personnel Error.Operator Counseled.Repairs in Progress to Repair Automatic Axial Flux Difference Monitor
05000400/LER-1992-011-02, :on 920721,determined That Testing of Emergency Bus Undervoltage Log Circuitry Inadequate.Caused by Inadequately Prepared Surveillance Test procedures.OST-1823 & OST-1824 Will Be Revised
05000400/LER-1990-013, :on 900503,valve Misalignment Caused Unplanned Release from Waste Gas Sys to Waste Process Bldg Vent Stack 5.Valve Position Corrected,Procedures Changed & Training of Personnel Initiated
05000400/LER-1990-006, :on 900309,discovered That Evolution Violated Requirements of FSAR to Keep Individual Tanks Isolated from Another Tank.Caused by Failure to Address Evolution in Operating Procedure.Procedure Revised
05000400/LER-1990-014, :on 900516,discovered That Two Liquid Radioactive Releases Initiated on 900513 Were in Excess of Flow Rate Specified on Release Permits.Caused by Personnel Error.Max Release Rate Must Be Recorded
05000400/LER-1991-001, :on 910103,operations Personnel Identified Procedural Deficiency That Resulted in Check Valves Not Being Tested as Required.Caused by Procedural Deficiency. Procedure Revised to Incorporate Testing
05000400/LER-1989-017-01, On 891009,generator & Main Power Transformer Phase Differential Relay Tripped Lockout Relay.Caused by Multiple Ground Faults.Design Changes & Repairs Being Conducted While Plant Performs Refueling
05000400/LER-1989-017-03, :on 891009,turbine & Reactor Tripped Due to Generator & Main Power Transformer Phase Differential Relay Trip.Caused by Multiple Shorts to Ground.Design Changes & Repairs Being Conducted
05000400/LER-1989-015-01, :on 890827,discovered That Fuel Handling Bldg Operating Floor Equipment Hatch in Storage Location on Operating Deck Not Installed as Required.Caused by Inadequate Procedure.Procedure Revised
05000400/LER-1989-004, :on 890207,loss of All Three Circulating Water Pumps Resulted in Loss of All Flow to Main Condenser, Causing Reactor Trip.Caused by Air Entering Circulating Water Pump Seal Water Sys.Components Repaired
05000400/LER-1990-016, :on 900529,invalid Testing of Fuel Handling Bldg Emergency Exhaust Filtration Unit Occurred.Caused by Inadequate Location of Duct Flowrate Measurements.Test Procedure for Filtration Units Will Be Revised
05000400/LER-1988-033, :on 881125 & 1202,declared Charging Safety Injection Pump (Csip) Inoperable.Caused by 1C Csip Scantily Covered in ESF Response Surveillance Test Procedures.Test to Verify 1C Csip Response Time Completed
05000400/LER-1988-023, :on 880812,reactor Coolant Sys Vent Less than Required by Tech Spec 3.4.9.4 for Low Temp Overpressure Protection.Caused by Failed Valve Gagging Device.Longer Gagging Device Installed
05000400/LER-1988-031, :on 880614-21 & 0723-26,wide Range Gas Monitor Inoperable & Compensatory Actions Not Taken or Documented as Being Taken as Required Due to Personnel Error.Caused by Failure to Install EC4-X as Required
05000400/LER-1988-024, :on 880812,maint Surveillance Tests Verifying Nuclear Instrumentation Source Range Monitor Operability Not Performed Prior to Mode 6 Entry.Caused by Deficient Planning & Scheduling.Surveillance Tests Scheduled
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
05000400/LER-1987-056, :on 870924,reactor Tripped Due to Deenergization of P-13 Permissive Bistable.Caused by Personnel Error Due to Insufficient Instructions.Procedure for Mod Implementation Revised
05000400/LER-1987-047, :on 870804-05,auxiliary Feedwater Actuations Occurred Due to Trips of Main Feedwater Pump 1A.Caused by Discharge Pressure Switches Out of Calibr.Discharge Pressure Switches Recalibr
05000400/LER-1987-016, :on 870323 & 26,turbine Bldg Vent Stack Monitor Declared Inoperable Due to Problems W/Water in Monitor.On 870327,monitor Declared Operable & Lined Up to Sample Stack. Turbine Bldg Vent Stack Reinstated
05000400/LER-1987-034, :on 870611,air Leakage by Inner & Outer Doors of Personnel Air Lock Excessive.Caused by Flat Spots on O-ring Seal.Seals on Inner & Outer Doors Replaced & Procedure OMM-001 Revised
05000400/LER-1987-024, :on 870421,heater Drain Pumps a & B Tripped Due to Low Differential Pressure & Automatic Turbine Runback Initiated.Caused by Oscillating Feedwater Heater Levels.Pump Low Level Trip Setpoint Lowered
05000400/LER-1987-011, :on 870307,breaker Tripped Open Causing de-energization of Auxiliary Bus 1E.Caused by Procedural Inadequacy.Defective PIC Card in Power Supply to LT-112 Relay Replaced & Procedure Revised
05000400/LER-1987-039, :on 870619,intermediate Range (IR) High Neutron Flux Trip Setpoint Found Out of Calibr.Caused by Previous Adjustment to IR Setpoints.New Scaling Currents for 25% Trip Incorporated Into Applicable Procedures
05000400/LER-1987-013, :on 870313,plant Manually Tripped at 49% Power Due to Loss of Main Feedwater.Caused by High Discharge Pressure Spike of Condensate Booster Pumps.Feedwater Regulating Valves Stroked
05000400/LER-1987-036, :on 870621,air Roll of 1A-SA Diesel Engine Not Performed within 4 to 8 H After Engine Shutdown.Caused by Marking in Test Procedure Step as Not Applicable.Engine Air Rolled.No Accumulation of Water Detected
05000364/LER-1917-004, Regarding Turbine-Driven Auxiliary Feedwater Pump Steam Admission Valve Air Leak Resulted in a Condition Prohibited by Technical Specifications
05000250/LER-1998-004-02, :on 980921,automatic Reactor Trip Occurred. Caused by Inadequate re-correlation of Intermediate Range Neutron Flux Instrumentation Reactor Trip Bistable. Enhanced Applicable Plant Procedures.With
05000250/LER-1990-019, :on 901003,alarm Received on Control Room Annunciator X-7/6 Indicating Heat Tracing Trouble.Caused by Inadequate Work Control.Boric Acid Transfer Pumps Aligned & Event Discussed W/Shift Supervisor
05000251/LER-1990-007-02, :on 900726,component Cooling Water Pump 4A Automatically Started.Caused by Error Made by Nonlicensed Personnel.Pressure Controller PC-4-611 Recalibrated
05000251/LER-1988-011-01, :on 880816,damage Occurred to Property in Excess of $2,000 Due to Spent Fuel Pool Leakage.Caused by Pump Failure Causing Vent Valve to Vibrate Open.Floor Drain Sys Cleaned.Pump & Oiler Repaired & Inspected
05000250/LER-1989-005-01, :on 890215,auxiliary Feedwater Flow Automatically Initiated Following Attempt to Start Steam Generator Feedwater Pump.Caused by Wiring Error on Starting Circuit Relay.Wiring Error Corrected
05000250/LER-1988-013, :on 880707,discovered That Monthly Channel Functional Test Surveillance Procedure Did Not Check Sys Alarm.Caused by Personnel Error.Surveillance Procedure Corrected & Personnel Counseled
05000250/LER-1989-002, :on 890116,normal Plant Cooldown Initiated Due to Small Boundary Leak of Rcs.Caused by Transgranular Stress Corrosion Cracking in Mapping Sys Thimble Guide Tube J-12 & J-7.Guide Tubes Involved Repaired or Replaced
05000251/LER-1987-010-02, :on 870522,emergency Diesel Generator auto-started During Testing of 4,160-volt Bus Undervoltage Protection Circuit.Caused by Personnel Error.Personnel Counseled & Procedure Revised
05000250/LER-1987-015, :on 870522,design Basis Reconstitution Revealed Potential Loss of HVAC in Inverter & Battery Rooms.Caused by Mods to Original Plant Design.Maint & Insp Procedures Implemented for Air Conditioning Units
05000251/LER-1987-025-01, :on 871012,containment Vent & Control Room Ventilation Isolation Actuated.Caused by High Levels of Rb-88 in Containment Following Unit Shutdown.Containment Activity Level Returned to Normal
05000251/LER-1989-009-01, :on 890823,boric Acid Transfer Pump Seal Pot Found W/No Visible Level Resulting in No Flow Path to Rcs. Caused by Design of Boric Acid Transfer Pump Double Seals. Review Continuing for Alternate Seal Design
05000250/LER-1988-027, :on 881006,mechanic Found to Be Contaminated When Exiting Containment Bldg.Specific Cause Unidentified. Addl Temporary Controls Implemented & Area Mopped
05000250/LER-1989-008, :on 890320,heat Trace Circuits 8A & 8B on Suction Lines of Boric Acid Transfer Pump Declared Out of Svc.Possibly Caused by Leaking Isolation Valve.Isolation Valve Disassembled for Insp
05000251/LER-1988-012-01, :on 880905,control Rod K-12 Dropped from 228 Steps to 0 Step,Causing Turbine Runback to 60% Power.Cause of Drop Under Investigation.Insp of Control Rod K-12 Will Be Performed During Current Refueling Outage
05000250/LER-1988-023, :on 880926,chemistry Technician Reported That There Was No Flow Indication to Plant Process Radiation Monitor R-19.Caused by Solids from Steam Generator Blowdown. Sample Flows to R-19 Will Be Monitored
05000250/LER-1988-025, :on 881013,determined That Potential Interaction Existed Between Emergency Diesel Generator Pump Control Sys Which Could Have Prevented Fulfillment of Safety Function.Caused by Inadequate Design
05000250/LER-1988-019, :on 880822,boric Acid Transfer Pump 3A Declared out-of-svc.Caused by Lack of Visible Water Level & Zero Nitrogen Pressure in Seal Pot & Failure of Pump Seal.Seal Replaced & Pump Returned to Svc
05000250/LER-1988-008, :on 880613,flowpath Which Could Result in Insufficient NPSH to Certain Pumps During LOCA Recirculation Identified.Procedures Revised to Maintain Valve 887 Locked in Fully Open Position
05000251/LER-1988-004-02, :on 880408,Tech Spec Table 3.5-2 Requirements Exceeded.Caused by Failure of Relays 327TX/4A2 & 327TX/4A2 in Undervoltage Protection Scheme for 4A 480 Volt Load Ctr. Relays Replaced & Tested
05000250/LER-1988-016, :on 880811,containment Spray Pump out-of-svc for Maint Exceeding Tech Specs Limits.Caused by Lack of Knowledge Re Need for break-in Period for New Bearings. Training Procedures to Be Revised
05000251/LER-1987-026-01, :on 871121,component Cooling Water (CCW) Pump 4B Autostarted During CCW Pump 4C Return to Svc.Caused by Insufficient Margin Between Operating & Setpoint Pressures.Increased Margin Initiated
05000251/LER-1987-014-01, :on 870711,dripping from Auxiliary Feedwater Steam Line Discovered.On 870714,leak Identified as Pinhole on Reducer.Cause Unknown.Fitting & Portion of Adjacent Piping Removed for Analysis
05000251/LER-1987-015-01, :on 870715,technicians Failed to Deactivate Inoperable Containment Isolation Valve within 4 H as Required by Tech Specs.Caused by Personnel Error.Procedure Completion Responsibility Centralized
05000251/LER-1987-012-02, :on 870705,during Unit 3 Engineered Safeguards Integration Test,Auto Start of Component Cooling Water Pump 4B Occurred.Caused by Low Header Pressure on Increased Cooling Water Flow.Procedure Will Be Enhanced
05000250/LER-1987-034, :on 871229,manual Reactor Trip from Approx 70% Reactor Power Occurred,Caused by Stuck Contacts on Overspeed Controller 20% Underpower Relay.Contacts Freed & Cleaned. Inputs to Relay Satisfactorily Calibr
05000250/LER-1987-023, :on 870913,safety Injection Sys Actuation & Subsequent Reactor Trip Occurred.Caused by Component Failure & Personnel Error.Event Response Team Formed to Investigate Causes & Initiate Corrective Action
05000251/LER-1987-019-01, :on 870712,turbine Runback from 89% Reactor Power to 84% Reactor Power Occurred.Caused by Spurious Spike in Rod Position Indication Sys.Faulty Solder Joint Repaired & Signal Conditioners Inspected
05000250/LER-1987-022, :on 870731,operator Demonstrated Known Spurious & Spiking Problem in Nuclear Instrumentation Sys Intermediate Range Channels,By Opening Drawer for Sys. Caused by Faulty Locking mechanism.W/870831 1tr
05000315/LER-1987-004, :on 870408,unit Shut Down Due to Unidentified RCS Leakage Per Tech Spec 3.4.6.2.Caused by Leakage Greater than 1 Gpm from Letdown Isolation Valve.Leakage Sources Repaired
05000316/LER-1988-001, :on 880106,Tech Spec 3.3.3.10 Discovered Not Met for 871230-880106 Due to Discovery of Incorrect Lineup for Radiation Monitor VRS-2500.Caused by Personnel Error. Flow Restored to Monitor & Lineup Verified
05000316/LER-1987-008-01, :on 870722,ESF Actuation Occurred Due to Extreme High Level in Steam Generator 24.Caused by Erratic Response of Main Feedwater Pump Delta P Controller. Plant Procedures Implemented
05000316/LER-1994-006-01, :on 940906,six MSSVs Failed to Meet TS Lift Setpoint Requirements.Caused by Galling Between Valve Disk & Nozzle.Nrr Issued TS Amend 167 to Unit 2 Ts,Increasing MSSV Tolerance on 940909
05000316/LER-1994-007, :on 940909,containment Type B & C Leakage Exceeded LCO Value Due to Leakage of Post Accident Sample Line Check Valve.Containment Isolation Valves Exhibiting Excessive Leakrates Repaired & Retested
05000315/LER-1994-001, :on 940203,04 & 05,13 of 20 MSSVs Lift Settings Found Out of Tolerance.Caused by Mild Galling Between Disk & Nozzle Components.Valve Mfg Recommended That Nozzle & Disc Seatingsurfaces Have Grey Matt Finish
05000316/LER-1993-006, :on 930709,TS 72 H LCO Action Statement Exceeded Due to Time Required for Repair of Charging Pump. Charging Pump Rotor Assembly Removed & Rebuilt Assembly Installed
05000315/LER-1992-007, :on 920705,accumulated Leakage for Type B & C Leakrate Tests on Containment Penetrations Exceeded TS Lco. Caused by Scale on Valve Seat & Small Crack in Surface of Neoprene Seat.Stop Nuts Adjusted
05000315/LER-1990-010, :on 900824,discovered That Routing Cable Associated W/Unit 1 Low Shutdown Indication Panels Not in Compliance w/10CFR50,App R.Minor Plant Mod Initiated to Provide Encl (Wrapped) Around Subj Conduit
05000316/LER-1993-004, :on 930408,rod Position Indication for Rods H-12 & M-8 Found Indicating Greater than 12 Steps from Demand Position Indication.Caused by Transformer Sensitivity to Temp Changes.Position Verified
05000315/LER-1990-015, :on 901102,discovered Containment Type B & C Leakage Exceeded L.C.O. Value Due to Degradation of Isolation Valve Seating Surfaces.Seat Was Lapped & Disc Was Replaced
05000315/LER-1992-008, :on 920805,spent Fuel Exhaust Ventilation Sys Declared Inoperable Due to Unacceptable Leakage Around Charcoal Absorber.Caused by Aging & Lost of Pliability of Seal Matl.Matl Replaced & Sys Returned to Svc
05000316/LER-1993-003, :on 921016,discovered That Charcoal Filter Face Dampers Were Closed Instead of Open as Indicated.Caused by Incorrect Solenoid Installation.Procedures Revised & Dampers Verified to Be Installed Correctly
05000315/LER-1992-006-02, :on 920618 & 19,10 of 20 Main Steam Safety Valve Lift Settings Found Outside of TS Tolerances.Caused by Setpoint Drift.Valves Reset to Acceptable Values & Retested Satisfactorily
05000316/LER-1992-003, :on 920219,20 & 21,7 of 20 Main Steam Safety Valve Lift Setting Found Outside of TS Established Limits. Caused by Setpoint Drift.Setpoint Ranges Reset & Maint Procedure for Valve Repair Revised
05000315/LER-1992-011, :on 920917,identified That Post Accident Containment Hydrogen Monitoring Sys Operability Per License Commitments Could Not Be Assured.Caused by Inadequate Evaluation.Plant Modification Initiated
05000315/LER-1990-016, :on 901221,determined That Two of Three Safety Valves Had Lift Settings Outside TS 4.4.3 Acceptance Criteria.Possibly Caused by Steam Cutting in Disc Insert & Nozzle.Valves Satisfactorily Tested
05000316/LER-1992-008-01, :on 920928,EDG Tripped on lo-lo Lube Oil Pressure 24 After Start.Caused by Abnormally Low Level of Oil in Lube Oil Sump Tank.Tank Level Restored to Normal Operating Range & Mechanical Seal Replaced
05000315/LER-1990-012, :on 901015,failed to Comply W/Tech Spec When Fire Watch Posting Miscommunicated
05000315/LER-1989-004, :on 890324,leakage Found on Containment Penetrations Exceeded Tech Spec 3.6.1.2.b Requirement.Caused by Excessive Leakage Rate of Valves WCR-924,ECR-26 & ECR-31. Faulty Valves Repaired & Restested
05000316/LER-1989-009, :on 890331,discrepancy Noted in Westinghouse P-250 Computer Calculated Thermal Power Value Which Could Lead to Exceeding Rated Thermal Power.Caused by Not Including blowdown-mass Enthalpy Term
05000315/LER-1990-005-01, :on 900724,grace Period Requirement of 25% of 18 Month Surveillance Interval for Tech Spec Exceeded.Caused by Incorrect Entry Into Computerized Schedular Program. Schedule Reprogrammed
05000315/LER-1990-006-01, :on 900730,confirmed That Inadequate Emergency Lighting Placed Plant in Condition Not Covered by Emergency Procedures.Caused by Failure to Review Changes to Emergency Remote Shutdown Procedures
05000315/LER-1989-012-01, :on 890913,solid State Protection Sys Surveillance Testing Performed on Train B While Train a Safety Injection Pump Inoperable.Caused by Personnel Error. Breaker Surveillance Test Procedures Revised
05000315/LER-1990-004-01, :on 900508,reactor Operator Inadvertently Started Containment Recirculation Fan Instead of Hydrogen Recombiner During Surveillance Test.Caused by Inadequate Work Practice.Condenser Restored
05000316/LER-1989-002, :on 890116,seismic Restraint,Located on 24-inch ECCS Suction Line,Noted to Have Significant Deformation. Probably Caused by Removal & Reinstallation of Piping During Startup.Mod Initiated to Repair Restraint
05000315/LER-1989-007-01, :on 890414,Fire Door 422 in Demineralizer Valve Gallery,High Radiation Area Not Inspected Per Tech Spec 4.7.10.2a.Cause Not Stated.All Surveillances Assigned to Personnel Reconducted for Other Discrepancy
05000315/LER-1988-007-01, :on 880908,flow Passage Insp of Ice Condenser Revealed Frost & Ice Buildup.Caused by Sublimation of Ice or High Humidity in Containment Air.Flow Passages Manually Cleaned to Remove Accessible Frost
05000315/LER-1988-005, :on 880705,two CO2 Protected Areas Isolated W/O Compensatory Action Required Per Tech Specs.Caused by Personnel Error/Procedural Noncompliance.Administrative Actions Re Involved Individuals Taken
05000316/LER-1989-014, :on 890814,reactor Protection Sys Actuation Occurred Due to Failure of Class 1E Power Supply Inverter. Caused by Failed Silicon Controlled Rectifier in Static Transfer Switch.Inverter Repaired
05000316/LER-1990-013-01, :on 901215,during Tech Spec Surveillance,Plant Battery Declared Inoperable When Single Cell Voltage Decreased Below Test Limit.Caused by Improper Setpoint. Setpoints Verified & Corrected as Needed
05000315/LER-1989-009, :on 890705,disovered That Testing Document for Valve 1-CS-443-2 Not Signed Off.Record Search Conducted & No Evidence Found to Indicate That post-maint Testing Performed.Caused by Personnel Error
05000316/LER-1987-015-01, :on 871120,facility Entered Tech Spec 3.0.3 Due to Corrective Maint.Caused by Time Needed to Repair Separated Voltage Cable Connector Broken Due to Frequent Use.Connector Replaced
05000315/LER-1988-012, :on 881111,turbine Room Sump Not Sampled & Analyzed in Accordance W/Tech Specs.Caused by Personnel Error.Procedures Updated to List Required Sampling Frequencies & Analysis for Sys
05000315/LER-1987-022, :on 871007,as Found Data of Two Pressurizer Level Channels Exceeded Tech Spec Limiting Condition for Operation.Caused by Transmitter Calibr Shift.Calibr Checks for New Transmitter Installations Planned
05000315/LER-1988-002-01, :on 880326,ice Buildup in Ice Condenser Flow Passages Declared Inoperable.Caused by Sublimation of Ice or High Humidity in Containment Air.Flow Passages Manually Cleaned to Remove Frost
05000316/LER-1988-007, :on 880613,use of Incorrect ISI Ref Values Resulted in Literal Violation of Tech Spec 3.5.2.Event Originally Reported on 871224.Caused by Personnel Error. ISI Documents Revised
05000316/LER-1987-010-01, :on 870902,insps Revealed Frost & Ice Buildup on Lattice Frames of Greater That 3/8 Inch in 46 Flow Passages & 6 of 24 Ice Condenser Bays.Caused by Abnormal Degradation.Ice Condenser Defrosted
05000315/LER-1987-014, :on 870812,failure to Comply W/Tech Spec Requirements for Testing of Turbine & Motor Driven Auxiliary Feed Pumps & Emergency Diesel Generators Occurred.Caused by Procedural Deficiencies.Procedure Revised
05000315/LER-1987-018, :on 870826,certain Fire Rated Assemblies & Dampers Declared Inoperable Due to Incorrect Application of Surveillance Requirements.Caused by Personnel Error. Administrative Actions Taken Re Individual
05000315/LER-1987-016, :on 870815,discovered That Boron Injection Sys Distribution Flow Not in Compliance W/Tech Spec Requirements.Caused by Normal Sys Fluctuations Combined W/ Instrument/Measurement Error.Flow Reconciled
05000316/LER-1987-005-01, :on 870602,ESF Actuation Occurred Due to Low Low Steam Generator Level in Steam Generator 23.Caused by Personnel Error.Appropriate Administrative Action Taken Re Personnel.Procedures Implemented
05000316/LER-1987-006-01, :on 870615,containment Spray Pumps Declared Inoperable Due to Improperly Performed Tech Spec Surveillances Testing.Caused by Improper Labeling of Flow Instrumentation Being Maintained.Pumps Tested
05000315/LER-1987-008, :on 870604,ESF Actuation Occurred Due to Extreme High Level in Steam Generator 12.Caused by Mispositioning of Both Level Controller & Feedwater Flow Selector Switch.Level Controller Refurbished
05000316/LER-1987-004-01, :on 870601,turbine Trip/Reactor Trip Occurred Due to Loss of Main Condenser Vacuum.Caused by Failure of Manual Isolation Valve.Procedures Implemented to Verify Proper Response of Automatic Protection Sys
05000316/LER-1987-003, :on 870107,overpower Delta Temp Bistables Failed to Trip During Instrumentation Calibr.Caused by Procedural Deficiency & Personnel Error.Procedure Revised
05000316/LER-1987-002, :on 870305-06,frost & Ice Buildup on Lattice Frames & Between Walls & Ice Baskets Adjacent to Walls Exceeded Tech Spec 4.6.5.1.b.3 Limits.Cause to Be Investigated by Westinghouse.Internal Investigation Begun
05000315/LER-1986-021, :on 860925,RHR Sys May Have Been in Analyzed Configuration Re LOCA Analysis.Caused by Misunderstanding of Tech Spec 3.5.2.Caution Tags Placed on Safety Injection & RHR Sys to Prevent Isolation
05000316/LER-1987-001-01, :on 870303,spurious Signal from Source Range Instrument Channel N-31 Resulted in ESF Actuation.Caused by Malfunction of Detector.Source Range Instrument Detector Removed,Replaced & Declared Operable on 870314
05000315/LER-1987-013, :on 870701 & 02,ice Buildup Discovered in Ice Condenser Flow Passages.Caused Possibly by Sublimation of Ice or High Humidity in Containment Air.Condenser Defrosted & Matter Discussed W/Utils That Have Same Unit
05000528/LER-1995-002, :on 950303,identified That Slb Analyses Failed to Consider as Initial Condition One Percent SDM for All Rods in (ARI) Due to Lack of Coordination & Unclear Div of Responsibilities.Ari Core Data Book SDM Curves Modified
05000528/LER-1995-003-01, :on 950729,switchyard Voltage Dropped Below Administratively Imposed Limit of 524 Kv for Approx 10 Seconds Due to Transient Grid Voltage.No C/A Taken Since Transmission Sys Transient Short Duration
05000335/LER-1997-011, :on 971102,non-conservative RAS Set Point Resulted in Operation Prohibited by Ts.Caused by Inadequate Set Point & Instrument Loop Scaling Process.Revised ESFAS Functional Tp W/Proper Set Point
05000389/LER-1995-005-02, :on 951120,2A EDG Relay Socket Failures Occurred Due to High Cycle Fatigue.Replaced Degraded Relay Sockets & 2A & 2B EDGs Run for 24 H Each,At Full Load After Replacement of Degraded Relay Sockets
05000528/LER-1995-007, :on 950512,determined That Bench Settings of air-operated Letdown & Containment Isolation Valves Adversely Affected Ability of Valves to Perform 10CFR50 App R Safety Function.Affected Valves Modified
05000335/LER-1989-001-03, :on 890517,inadvertent Liquid Release from Waste Mgt Sys Occurred.Caused by Personnel Deviation from Procedure OP 1-0510022 W/O Prior Initiation of Temporary Change Due to Out of Svc Valve
05000528/LER-1989-020, :on 890907,emergency Diesel Generator B, Essential Spray Pond Pump B & Essential Cooling Water Pump B Started During Removal of Jumpers.Caused by Personnel Error. Maint Procedure Revised
05000528/LER-1989-013, Forwards Suppl 1 to LER 89-013-00.Rept Being Submitted to Include Info Requested by Part 21
05000528/LER-1989-006-01, :on 890731,containment Purge Isolation Actuation Signal Initiated Due to Loss of Power to Panel 1E-PNB-D26.Cause Not Identified.Power Restored & Radiation Monitor RU-38 Placed Back on Line
05000528/LER-1991-001, :on 910110.determined That Postulated Break in Reactor Coolant Pump High Pressure Seal Cooler Could Result in RCS Leak Outside Containment.Caused by Tube Rupture in Seal Cooler.Rcs Activity Monitored
05000528/LER-1988-016, :on 880514,reactor Trip Occurred.Caused by Nonconservative Operator Performance During Reactor Startup. Info Utilized for Estimated Critical Condition Will Be Corrected
05000530/LER-1990-002, :on 900222,locked High Radiation Area Gate Found Open & Unguarded.Caused by Personnel Error.Radiation Protection Personnel Verified Room Unoccupied & Secured Gate Per Approved Procedure
05000530/LER-1988-008-02, :on 890220,determined That Excessive Moisture Condensation Occasionally Discovered in Unit Resulted in Invalid Sample Results.Caused by Cooling of High Humidity Sample Stream.Temporary Heat Trace Installed
05000529/LER-1987-021, :on 871202,post-accident Sampling Sys Declared Inoperable.Caused by Personnel Error.Appropriate Functional & Surveillance Tests Completed & Sys Decalred Operable.W/
05000529/LER-1987-002-01, :on 870320,Class 1E Train B Bank of Pressurizer Backup Heaters Could Not Be Energized from Control Room,Per Tech Spec Requirement.Caused by Malfunction of Heater Breaker & Personnel Error.Breaker Replaced
05000529/LER-1987-004-01, :on 870416,reactor & Turbine Trip Occurred. Caused by High Local Power Density Trip Signals Generated by Core Protection Calculators.Effects of Cycling Each Breaker Will Be Incorporated Into Guidelines
05000397/LER-1997-004, :on 970327,plant Operators Manually Scrammed Reactor as Required by TS Due to Indication of Entry Into Region a of power-to-flow Map.Caused by Inadequate Attention to Detail.Established Event Evaluation Teams
05000397/LER-1996-001, :on 960425,inadvertent ESF Actuations Occurred Due to Tripping of Temporary Power Supply to IN-3.Caused by Personnel Error.Operations Restored to IN-3 Loads & Reset ESF Actuations
05000397/LER-1994-005, :on 940326,control Rod Failed to Scram Due to Degradation of Pilot Valve Elastomers.Caused by Inservice Aging.Scram Time Tests Performed Weekly of Operable Control Rods & SSPVs Replaced
05000397/LER-1991-028, :on on 910930,containment Airlock Door Seal Leakage Test Not Performed within Allowable Surveillance Interval.Caused by Inadequate Personnel Work Practices. Master Startup Checklist Amended
05000397/LER-1991-030, :on 911104,small Leak Noted in Welded Connection Between RHR Sys Drain Valve & RHR Loop a Shutdown Cooling Return Valve.Caused by Const Fabrication Defect.Rhr Valve V-161A Isolated from RCS
05000397/LER-1991-013, :on 910507,non-compliances W/Tech Specs Identified as Part of Program of Surveillance Procedure Verification.Further Evaluation Performed.Quality Action Team to Be Chartered to Evaluate Program
05000397/LER-1991-007, :on 910415,reactor Scram & Shutdown Cooling Insulation Occurred Causing Automatic Actuation.Caused by Inadequate Work Instruments.Plant Control Room Operators Reset Scram Signal
05000397/LER-1991-012, :on 910506,manual Initiation of Reactor Protection Sys Occurred Due to Low Scram Air Header Pressure.Caused by Hose Failure.Hose Replaced
05000397/LER-1991-011, :on 910429,ESF Actuation Occurred as Wire in Control Room Panel Inadvertently Cut.Caused by Equipment/ Design Deficiency.Operators Replaced Blown Fuse & Reset Isolation Logic Signal
05000397/LER-1990-005, :on 900209,nonsafety-related Circuit Breaker on Power Panel Tripped,Resulting in ESF Actuation.Caused by Equipment Mfg Error Involving Defect in Circuit Breaker Tripping Mechanism.Defective Breaker Replaced
05000397/LER-1990-003, :on 900126,HPCS Sys Pump Suction Valve Switchover Occurred During Performance of Procedure for Draining Ref Leg.Caused by Plant Configuration.Sys Restored to pre-event Lineup Status
05000397/LER-1990-014, :on 900703,HPCS Sys Pump Suction Switchover from Condensate Storage Tanks to Suppression Pool Occurred Due to Suppression Pool High Water Level Condition.Caused by Procedural Inadequacy.Procedures Modified
05000397/LER-1989-035, :on 890817,reactor Scram Occurred During Surveillance Testing of Reactor Level Instrument Associated W/Automatic Depressurization Sys.Caused by Personnel Error. Training Improved & Visibility Increased
05000397/LER-1989-034, :on 890811,six Class 1E 480 Volt Ac Motor Control Ctrs Declared Inoperable Due to Design Deficiency. Caused by Exclusion of Fault Tripping Coordination. Distribution Sys to Be Evaluated
05000397/LER-1989-024, :on 890614,secondary Containment Bypass Leakage Found Greater than Allowed by Design Basis.Caused by Equipment Design Deficiency.Check Valves in Common Discharge Line of CRD Pump Installed to Prevent Leakage
05000397/LER-1990-007, :on 900314,review of Plant Procedures Associated W/Diesel Generator Fuel Oil Testing Showed No Requirement to Check for Water in Day Tanks.Caused by Less than Adequate Procedure Preparation
05000397/LER-1989-023, :on 890531,ESF Isolations & Actuations Occurred Due to Loss of Reactor Protection Sys Bus During Testing. Caused by Personnel Error.Logic Sys Functional Test Procedure Revised.Test Engineer Counseled
05000397/LER-1989-025, :on 890617 & 18,three Separate But Related Events Occurred Which Caused ESF Isolations & Actuations During Excess Flow Check Valve Testing.Caused by Inadequate Procedure.Procedure Modified
05000397/LER-1989-007, :on 890316,discovered That Two Tech Spec Surveillance Procedures Re Fire Protection Zones for Standby Svc Water Pump Houses & Power Generation Control Cabinet Inconsistent.Action Statements Implemented
05000397/LER-1989-013, :on 890508,preliminary Calculations Indicated Potential Common Mode Failure of Redundant 120-volt safety- Related Devices.Caused by Less than Adequate Design Criteria to Limit Voltage Drops.Procedure Revised
05000397/LER-1989-004, :on 890226,mobile Crane Brought within Reach of safety-related Structures & Components W/O Safety Evaluation Being Performed.Caused by Lack of Procedures Controlling Use of Mobile Cranes.Crane Removed from Area
05000397/LER-1989-008, :on 890419,discovered That on 881202,Tech Spec Amend Request Submitted to NRC Describing Diesel Generator Trip Bypass Verification That Had Not Been Performed W/Ler Not Issued within 30 Days After Determination
05000397/LER-1989-016, :on 890514,reactor Operator Inadvertently Tripped Div 1 & 2 Offsite Power Supply Feeders Resulting in Loss of Power to Buses SM-7 & SM-4.Caused by Inadvertent Removal of Transformer Fuses.Fuses Reinserted
05000397/LER-1989-009, :on 880529,full Reactor Protection Sys Actuation Occurred Twice During Performance Testing.Caused by Inadequate Preoperational Test & trouble-shooting Procedures.Preoperational Procedure Revised
05000397/LER-1989-021, :on 890527,electrical Protection Assembly Breaker Tripped Causing Loss of Power to Reactor Protection Sys Bus B.Cause Unknown.Upgraded Breaker Equipment Will Be Installed
05000397/LER-1989-029, :on 890703,RWCU & RCIC Sys Isolation Occurred When RWCU-V-1 Closed as Part of Group 7 Nuclear Steam Supply Shutoff Sys Isolation.Caused by Inadequate Preparation & Review of Surveillance Test Procedure
05000397/LER-1989-018, :on 890522,reactor Protection Sys (RPS) a motor-generator Set Failed Resulting in Loss of Power to RPS Bus A.Caused by Component Failure.Motor Replaced
05000397/LER-1989-020, :on 890527 & 0605,during Local Leak Rate Testing,Valve RHR-V-9 Automatically Isolated.Caused by Procedural Inadequacy & Inadequate Corrective Action Following Second Event.Procedure Modified
05000397/LER-1989-012, :on 890505,unplanned Reactor Scram Occurred During Performance of Reactor Protection Sys Logic Sys Functional Test.Caused by Procedural Inadequacy.Procedure Will Be Revised to Provide Specific Resetting
05000397/LER-1989-027, :on 890630,determined That Two Seismic Supports Missing on PASS Containment Isolation Valves.Caused by Inadequate Work Practices & Training of Project Personnel. Tech Spec Action Statement 3.6.1 Entered
05000397/LER-1989-014, :on 890509,full Reactor Protection Sys Actuation Occurred.Caused by Accidental Movement of Local Power Range Monitor Cables.Scram Reset & Importance of Tying Cables Away from Working Area Stressed
05000397/LER-1989-030, :on 890210,HPCS Suction Valve from Suppression Pool Failed to Fully Open During Surveillance Procedure. Caused by Motor Operator HPCS-MO-15 Mfg Design Defect.Tech Spec Action Statements Entered & Valve Closed
05000397/LER-1989-017, :on 890520,outboard RHR Shutdown Cooling Valve Automatically Isolated,Causing Loss of Shutdown Cooling. Caused by Removal of Relay by Contractor Maint Electrician Installing Mod to Leak Detection Sys
05000397/LER-1988-017, :on 880615,problems W/Limitorque Models SMB-000 & SMB-00 Discovered W/Potential Defective Switches.Caused by Design Problem.Investigation & Evaluation of Switch Problems Immediately Initiated.Part 21 Related
05000397/LER-1989-026, :on 890619,testing Confirmed That Selected Steam Tunnel Penetrations Could Fail to Perform as Pressure Boundary Following Design Basis Main Steamline Break.Caused by Inadequate Design Mgt.Part 21 Related
05000397/LER-1990-024, :on 900907,diesel Generator Started on Undervoltage Due to Voltage Disturbances
05000397/LER-1989-022, :on 890530,loss of Secondary Containment During Core Alterations Due to Unisolatable Lines Occurred.Caused by Simultaneous Activities.Rhr Heat Exchanger Isolation Valves Closed to Reestablish Integrity
05000397/LER-1988-024, :on 880703,single Primary Containment Monitor Intermittently Exceeded 150 F Temp & Time Limit.Cause Contributed to Leaking Main Steamline Safety Relief Valves & Leaking Tailpipe Vacuum Breaker Valves
05000397/LER-1988-034, :on 880909,pipe Failure Caused by Introduction of Liquid Nitrogen Into Primary Containment Supply Purge. Inerting Nitrogen Supply Valve & Containment Supply Purge Shut to Terminate Containment Inerting
05000397/LER-1988-022, :on 880616,violation of Fire Zone in Radwaste Bldg Cable Spreading Room.Caused by Missing thermo-lag Insulation Due to Personnel Error.Outline of 20 Ft non- Combustible Zone Will Be Taped on Floor
05000397/LER-1988-026, :on 880715,determined That Sensing Line Support Hangers Would Not Withstand Design Basis Fire W/O Mod or Protection.Caused by Inadequate Design by Architect Engineer.Areas Placed on Hourly Fire Tour
05000400/LER-1987-032, :on 870602,radiation Monitor REM-21WL-3541 Sample Chamber Instead of REM-21WS-354 Drained for Disconnection Leaving Monitor Inoperable.Caused by Personnel Error.Procedure HPP-495 Prepared
05000397/LER-1988-002, :on 880122,discovered RCIC Pump Suction Line Failed to Meet Containment Isolation & Single Failure Design Criteria.Caused by Ae Design Error.Check Valve Installed & Ltr Re Error Sent to B&R.Part 21 Related
05000397/LER-1988-019, :on 880527,determined That Control Room Emergency Filtration Sys Actuation Occurred on 880520.Caused by Technician Failure to Reset Trip Logic During Response Time Test Due to Inadequate Procedure
05000397/LER-1988-006, :on 880213,series of Reactor Pressure Vessel Level Transients Resulted in Low Reactor Protective Sys Actuation Following Manual Scram.Caused by Procedural Inadequacy.Procedures Modified
05000397/LER-1988-009, :on 880401,standby Gas Treatment Sys Tech Spec Surveillances Not Performed within Time Limits.Caused by Personnel Error.Personnel Counseled & Procedure Revised to Provide Guidance When Surveillance Exceeded
05000397/LER-1988-007, :on 880214,rupture of Reactor Bldg Roof Occurred Due to HVAC Overpressurization Transient.Caused by Personnel Error.Equipment Operator Training Program & Investigative Process Being Developed
05000397/LER-1988-003, :on 880204,reactor Scram Due to Main Steam Line Isolation Occurred.Caused by Personnel Error.Rcic Sys Manually Initiated to Restore & Maintain Water Level. Procedure Revised & Technicians Counseled
05000397/LER-1987-033, :on 871218,plant Tech Spec Sections 4.0.5 Re ASME Valve in-service Testing Requirements & 3.6.3 Concerning Containment Valve Operability Not Met.Caused by Personnel Error.No Corrective Action
05000397/LER-1988-001, :on 880118,following Plant Shut Down,Automatic Reactor Protective Sys Actuation Occurred Due to Low Reactor Pressure Vessel Water Level Condition.Caused by Procedural Inadequacy.Plant Procedures Revised
05000244/LER-1993-004, :on 930707,Main Feedwater Isolations Occurred Due to Secondary Side & Condensate Feedwater Pressure Transient.Returned Feedwater Regulating Valves to pre-event Controls Configuration
05000244/LER-1992-006, :on 920518,main FW Isolations Occurred on SG a Due to Overfeeding SG a While in Manual Control.Caused by Heater Drain Tank Level Control Sys Problem.Administrative Controls Instituted to Ensure Valve Not Open
05000244/LER-1992-005, :on 920420,determined That 242 Tubes in a SG & 216 Tubes in B SG Required Corrective Action Due to Tube Degradation.Affected Tubes Either Sleeved or Plugged.W/
05000244/LER-1993-003, :on 930328,discovered Failures of Safeguard Svc Water Sys During Planned Maint.Caused by Design & Operating Environ.Replaced Affected Valves W/Qualified Spares.W/
05000244/LER-1992-003, :on 920229,reactor Trip Occurred Due to Lo Lo Level in Steam Generator B.Caused by Plugged Instrument Tubing for Feedwater Pump a Seal Injection Differential Pressure Switch.Turbine Flushed
05000335/LER-1999-004-01, :on 990912,noted That MSSV Surveillance Was Outside of TS Requirements.Caused by Setpoint Drift.Subject MSSVs Are Being Refurbished & Retested Prior to Unit Startup from SL1-16 Refueling Outage.With
05000389/LER-1999-003, :on 990406,ECCS Suction Header Leak Resulted in Both ECCS Trains Being Inoperable & Entry Into TS 3.0.3. Caused by Chloride Induced OD Stress Corrosion Cracking of Piping.Made Code Repairs & Coated Piping.With
05000389/LER-1999-006, :on 990605,sub-critical Reactor Trip Occurred Due to Inadvertent MSIV Opening.Caused by Personnel Error. Provided Operation Supervision Instruction to Operating Crews,Stand Down Meetings & Operator Aids.With
05000335/LER-1998-009, :on 981223,noted That Facility Operated Outside of Design Basis.Caused by non-conservative MSLB Analysis Inputs.Will Review SR Component Differences Between Units & Will re-baseline LTOP Analysis.With
05000389/LER-1997-002, :on 981204,containment Sump Debris Screen Was Not IAW Design.Caused by Inadequate C/As for Sump Screen Anamolies.All Identified Sump Screen Deficiencies Were Dispositioned &/Or Repaired.With
05000389/LER-1998-010, :on 981207,RCS Boron Sample Frequency Required by Ts,Was Exceeded by Twelve Minutes.Caused by Personnel Error.Equipment Clearance Order Was Lifted to Draw Required Sample & Operations Procedure Was Changed.With
05000389/LER-1999-002, :on 990311,SG ECT Error Caused Operation with Condition Prohibited by Ts.Caused by Deficiencies in Data Analysis Guideline Instructions.Licensee Will Change Data Analysis Guidelines for Lead Analysts.With
05000335/LER-1998-008, :on 981008,inadequate Reactor Protection Sys Trip Bypass TS Was Noted.Caused by Poorly Worded Ts. Submitted LAR to Clarify Power Requirements for High Rate of Power Trips.With
05000389/LER-1998-008-01, :on 981118,missed TS SG U Tube Insp.Caused by Encoding Errors While Using Remote Positioning Fixtures.All SG Tube Surveyed.With
05000389/LER-1998-003-01, :on 980326,discovered Containment Pressure Instrumentation Design Single Failure Vulnerability.Caused by Inadequate Design by Personnel Error.Removed RPS & ESFAS Containment Pressure Bypass Keys Immediately
05000335/LER-1998-006, :on 980421,missed EDG Fuel Oil Sample Surveillance Was Noted.Caused by Personnel Error.Revised Fuel Oil Sampling Service Purchase Order & Revised Site Procedure
05000389/LER-1998-004-01, :on 980430,discovered Waste Gas Decay Tank Operation W/O Available Oxygen Analyzers,Which Is Prohibited by Ts.Caused by Inadequate Licensee Review of License Amend. Oxygen Analyzer Recalibrated
05000389/LER-1998-007-01, :on 980918,identified Discrepancies Between Fire Protection Design Requirements & Field Conditions. Caused by Inadequate Translation & Implementation of Fire Protection Requirements.Procedures Revised.With
05000335/LER-1998-005, :on 980305,identified Two Conditions That Were Outside App R Design Bases.Caused by Design Oversight During Development of Original App R Safe SD Design.Established 30 Minute Roving Fire Watches & Provided Training
05000389/LER-1998-005, :on 980807,discovered That New MOV Methodology Caused Past PORV Block Valve Operability Problem.Caused by Inadequacies in Original Vendor MOV Methodology.Planned Valve Mods Will Be Implemented During Cycle 11 1998 Outage
05000389/LER-1998-006-01, :on 980918,inadvertent Afas Actuation Was Noted.Caused by Degradation of Multiple Afas Power Supplies. Replaced Afas Power Supplies & Revised Procedures.With
05000335/LER-1997-007, :on 970502,reactor Coolant Pump Oil Collection Sys Was Outside App R Design Bases.Identified Leak Sites Were Repaired & Mods to RCP Oil Collection Sys to Capture Any Future Leakage from Areas
05000335/LER-1997-003, :on 970304,automatic RT Resulted from Loss of Electrical Power to 1A2 Rc Pump.Rcp Breaker Was Replaced & Pump Was Returned to Svc
05000335/LER-1998-007, :on 980630,inadequate Procedure May Have Resulted in SBO Recovery Complications.Caused by Inadequate Procedures.Attached Caution Tags to Appropriate Control Switches
05000335/LER-1996-011, :on 960817,discovered Failure of Oxygen Analyzer.Caused by Degraded Sensor Membrane in Oxygen Detector.Calibr,Tested & Returned Oxygen Analyzer to Service & Replaced Sensor Membrane
05000335/LER-1997-010, :on 971027,inadvertent Core Alteration Prohibited by TSs Were Noted Due to Stuck Cea.Caused by Personnel Error.Cea 24 Was Dislodged & Transferred to Spent Pool for Insp
05000335/LER-1997-001, :on 970221,identified Deficiencies in Post Accident Sampling Systems (Pass).Caused by Failure of Personnel to Specify Drawing Update Requirements.Added PASS to List of Maint Rule Systems
05000389/LER-1997-007-02, :on 971008,inoperable Containment Cooling Fan Resulted in Operation of Facility Outside Design Basis. Caused by non-cognitive Personnel Error.Ccs Operation Was Revised & Issued on 971013
05000389/LER-1997-003-02, :on 970521,determined Required Post Maint Open Stroke Test for Valve V3245,2B2 SIT Discharge Check Valve, Had Not Been Performed.Caused by Personnel Error.Procedure Revised
05000389/LER-1996-004-02, :on 960923,operation Prohibited by TS Occurred. Caused by Cognitive Personnel Error.Fpl Verified That a Successful Stroke Time Surveillance Was Conducted on FCV-25-7 & FCV-25-8
05000335/LER-1997-006, :on 970501,operation Was Prohibited by TS Due to Inadequately Tested Degraded Voltage Sys.Revised Unit 1 ESFAS Surveillance Test Procedure
05000389/LER-1996-007-02, :on 961211,operation Prohibited by TSs Occurred Due to Inadequate Surveillance of MSIS Actuation Logic. Testing of MSIS High Containment Pressure 2/4 Actuation Logic Was Satisfactorily Performed on 961211
05000389/LER-1996-002-02, :on 960606,reactor Manually Tripped.Caused by Positioner Feedback Arm Failure on Main Generator Hydrogen Cooler Tcv.Mods Made to Hydrogen Cooler TCV to Eliminate Feedback Assembly & Reduce Vibration
05000335/LER-1996-008-01, :on 960608,inadvertent Actuation of Safety Injection Actuation Signal & Containment Isolation Actuation Signal Occurred.Caused by Loss of Power Supply.Reviewed Power Supply Design & Conducted Visual Insp
05000335/LER-1996-009, :on 960710,operation Prohibited by Tss.Caused by Procedural Inadequacy & Personnel Error.C/As:Rev of Maint Procedures to Include Verification That Plant Conditions IAW TS Requirements Prior to Installation
05000335/LER-1996-001-02, :on 960219,control Room Emergency Ventilation Sys Inoperable Due to Improper Sys Configuration Occurred. Caused by Inadequate Guidance & Work Controls.Cr Boundary Reviewed
05000335/LER-1996-007-01, :on 960607,1B EDG Inadvertently Started Due to Procedural Inadequacy.Reset B Channel Cias & Reenergized 1B3 4,160 Bus from Startup Transformer.Changes Made to MPs 1-0970027 & 1-0970028
05000335/LER-1996-002-01, :on 960222,control Element Assembly Dropped on Unit 1 During Periodic Testing.Caused by Failed Silicon Control Rectifier in Upper Gripper Power Switch Module.Power Switch Modules Replaced
05000335/LER-1997-002, :on 970221,operation in Excess of Max Rated Thermal Power Occurred Due to Digital Data Processing Sys (Ddps) Calorimetric Error.Verified Acceptable Performance of Ddps Functions & Reviewed Software Mods
05000389/LER-1997-002-03, :on 970518,containment Sump Debris Screen Was Not IAW Design Due to Gaps in Screen Encl.Performed SER to Document Containment Sump Design Requirements
05000335/LER-1995-009, :on 951019,discovered TS Scheduled Surveillance Was Missed Due to Personnel Error.Operations Supervisor Issued Memo & Counseled & Disciplined Involved Individual
05000335/LER-1996-003-01, :on 960224,containment Particulate & Gaseous Monitor Was OOS & Resulted in Condition Prohibited by TS Due to Personnel Error.Capgm Was Placed Back in Svc
05000335/LER-1996-012, :on 960831,manual Reactor Trip Occurred.Caused by Increased Gas Accumulation in 1B Main Transformer. Insp of 1B Main Transformer Cooling Sys Performed & Oil Cooler Replaced
05000335/LER-1995-010-01, :on 951116,manual Reactor Trip Occurred Due to Degraded 24 Volt Dc Power Supply to 1B SG Main Feedwater Controller.Tested & Replaced Power Supply for 1B Feedwater Controller.W/Undated Ltr
05000389/LER-1996-005-02, :on 961206,determined That Independent Operability of Trip Coils Had Not Been Adequately Tested. Caused by Inadequate Surveillance Procedure.Performed Testing of Coils & Revised Procedures
05000335/LER-1992-004-02, :on 920521,relay Time Delay Settings Altered Due to Personnel Error.Remaining Load Sequence Timers on Both Units 1 & 2 Were Inspected to Ensure Thumbwheel Switches Were Set Correctly
05000335/LER-1992-005-01, :on 920629,discovered That EDG 1B Declared Out of Svc on 920618 W/O Two Operable Flow Paths & W/O Required Vol in Boric Acid Makeup Tank.Caused by Personnel Error. Personnel Counseled & Pump Returned to Svc
05000335/LER-1990-004-01, :on 900228,inadvertent Partial Actuation of Train a Containment Isolation & Containment Spray Sys Occurred
05000389/LER-1989-007-02, :on 890923,unit Experienced Dropped Control Element Assembly in Regulating Group 1.Most Probable Cause of Event Was Blown Fuse.Root Cause for Breaker Trip Not Conclusively Identified.Blown Fuse Replaced
05000335/LER-1988-008-02, :on 880920,power Supply Wire Lead Inadvertently Lifted When Personnel Removed Another Lead on Same Terminal Lug Connection Causing Reactor Trip.Caused by Personnel Error.Unit Stabilized in Hot Standby
05000389/LER-1987-007-02, :on 871125,reactor Tripped on Loss of Load Due to Turbine Trip Caused by Failure of Main Generator Exciter Bearing.Root Cause Is Personnel Error.Electrical Maint Personnel Trained & Procedures Revised
05000389/LER-1986-011, :on 860709,emergency Diesel Generator 2A Taken Out of Svc Due to Failure to Meet Required Start Time.Caused by Excessive Tightening of Friction Clutch Locknut.Cooling Fan Shroud Removed & Fan Repositioned
05000335/LER-1987-005-02, :on 870307,discovered Leakage Rate Exceeding Allowable Leakage Per Tech Specs.Cause by Adjustment Criteria on Resilient Valve Seat on Penetration Inboard Isolation Valve.Valves Repaired
05000335/LER-1987-016-02, :on 871029,reactor Tripped Due to Loss of Condensate Pump.Caused by Inadequate Operating Procedure. Procedure Being Revised.Plant Training Dept Will Review Loss of Condensate Pump
05000410/LER-1990-021-01, :on 901026,TS Violation Re RHR Sys Valve Tests Not Included in Inservice Test Pump/Valve Program Plan Occurred
05000354/LER-2016-006, Regarding Mode Change Without B Channel Level Instrumentation Operable
05000321/LER-2016-003, Regarding Reactor Coolant System Piping Has Unacceptable Weld Indication Discovered During Refueling Outage
05000331/LER-2015-002, Regarding Unanalyzed Condition Due to Degraded Primary Containment Suppression Pool Coating
05000219/LER-2015-002, Regarding Reactor Scram Due to Digital Protective Relay System Lockout
05000424/LER-2013-001, Unit 1, Regarding Failure to Comply with Technical Specification LCO 3.8.4
05000348/LER-2012-005, Joseph M Farley Nuclear Plant, Unit 1 Regarding Unit Shutdown Required by Technical Specification 3.8.1
05000424/LER-2012-001, Regarding Seismically Qualified RWST Aligned to Non-Seismic Piping
05000366/LER-2011-002, Regarding Corrosion Induced Bonding Results in Setpoint Drift for Multiple Safety Relief Valves
05000416/LER-2010-001, Regarding Automatic Reactor Scram on Decreasing Reactor Water Level Due to Inadvertent Reactor Feed Pump Trip
05000374/LER-2009-001, Main Turbine Trip and Reactor Scram Due to Digital Electro-hydraulic Control Circuit Card Failure
05000321/LER-2008-004, Power Supply Card Failure Causes Loss of Feedwater Flow Resulting in Manual Reactor Scram
05000321/LER-2007-002, Regarding ATTS Card Failure Results in High Pressure Coolant Injection System Isolation
05000220/LER-2004-004, Regarding Manual Reactor Scram Due to Failure of 13 Feedwater Flow Control Valve Positioner
05000220/LER-2003-004, Regarding Unplanned Inoperability of Emergency Cooling System Caused by Inadequate Review of Clearance for Replacement of Instrumentation Relay
05000220/LER-2003-001, From Nine Mile Point, Unit 1 Regarding TS Cooldown Rate Exceeded During Required Cooldown for a Failed Solenoid Actuated Pressure
05000220/LER-2002-002, Re Loss of One Control Rod Drive Pump Train Due to Circuit Breaker Failure
05000425/LER-2002-001, Re Unstaked Capscrews Renders Residual Heat Removal Pump Inoperable
05000313/LER-2002-004, Arkansas Unit 1, Reactor Coolant System Pressure Boundary Leakage from a Fatigue Stress Crack of a Weld Connecting a Drain Line to a High Pressure Injection Line
05000313/LER-2002-001, Arkansas Unit 1 Main Steam Safety Valve as-Found Lift Settings Were Not within Technical Specification Limits
05000255/LER-1994-015, :on 940601,electrical Cable Revealed to Be Not Environmentally Qualified for Use in Application Due to Installation of Nonenvironmentally Qualified Cable.Jco Initiated as Defined in GL 91-18
05000250/LER-1989-001, :on 890110,emergency Diesel Generator (EDG) B & Intake Cooling Water Pump 3A Out of Svc During Same Time. Caused by Operability Test Being Performed.Edg Returned to Svc on 890110 & Pump Checked
05000250/LER-1987-007-01, :on 870128,diesel Fuel Storage Tank Sample Did Not Meet Tech Spec Surveillance Requirements.Caused by Not Using Sampling Techniques in Accordance W/Std ASTM Sampling Procedures.Procedure Revised
05000250/LER-1988-001, :on 880113,unit Experienced Turbine Runback Due to Dropped Control Rod Assembly & Manual Subcritical Reactor Trip Occurred When Addl Control Rods Dropped Into Core. Caused by Personnel Error.Personnel Counseled
05000315/LER-1987-012, :on 870702,Type B & C Containment Leak Rate Tests Failed on Two Valves.Caused by Ripped Diaphragm on One Valve.Cause Unknown on Second Valve.Valves Repaired
05000483/LER-1987-011, :on 870605,ESF Switchgear Rooms Halon Sys Rendered Inoperable W/O Continuous Firewatch.Caused by Cognitive Util Personnel Errors.Work Authorizing Documents Rescheduled
05000318/LER-1996-001-01, :on 960227,breakers 552-41,552-21 & 552-61 Tripped Open in Plant Switchyard.Caused by Failure of Auxiliary Relay Card in Breaker 552-41.Failed Relay Card Replaced
05000317/LER-1995-007, :on 940719,Unit 1 Tripped from 100% Power as Result of RPS Actuation.Caused by Low SG Water Levels Due to Level Shrink.Actions Initiated to Facilitate Safe Unit Restart