05000327/LER-1989-007, :on 890319,train a Control Room Isolation Occurred.Caused by Incompatibility of Replacement Smoke Detector Unit Relay Contact Configuration W/Application Requirements.Work Request Initiated
05000382/LER-1998-016, :on 980730,failed to Meet TS Requirements for for RT Bypasses.Cause Not Determined Because of Age of condition.1E-4% Bistables for All for Channels of Excore Log Power Channels Were Declared Inoperable 980730
05000424/LER-1987-040, :on 870622,containment Ventilation Isolation Occurred.Caused by Personnel Error.Engineering & Maint Personnel Counseled Re Cause of Incident & Provided Guidance to Avoid Repetition
05000245/LER-1987-019-01, :on 870612,misorientation of Fuel Assembly Discovered.Caused by Failure to Load in Proper Orientation. Appropriate Core Verification Procedure Changes Being Implemented
05000382/LER-1997-023, :on 970708,EDG Fuel Sys Surveillance Was Missed Due to Failure of Personnel to Determine Intended Start & End Dates for SR 4.8.1.1.2.h.2 Interval.Submitted Application for Emergency Amend for Removal of SR
05000382/LER-1998-007, :on 980317,discovered That No Allowance for Instrument Loop Uncertainity Included in Surveillance for Chilled Water Outlet Temp.Caused by Failure to Consider Instrument Loop Uncertainty.Revised Task
05000341/LER-1987-020, :on 870528,automatic Start of Div II Emergency Diesel Generators Occurred.Caused by Repairman Working within Wrong Cabinet During Surveillance.Personnel Counseled & Events Details Will Be Reviewed W/Repairmen
05000382/LER-1998-005, :on 980312,missed Thermal Overload TS Surveillance Were Noted.Caused by Inadequate Review of 1992 Rev to TS 3.8.4.2 IAW GL 91-08.Thermal Overloads for 8 MOVs Were Subsequently Tested & Determined to Be Operable
05000306/LER-1997-004-02, :on 970926,determined That Maint Airlock Volumetric Test Exceeded TS 4.4 Required Limit.Caused by Misalignment of Operating Mechanism Shafts W/Shaft Seal Housings.Reduced Shaft Seal Leakages & Revised Procedure
05000409/LER-1999-001, :on 990305,excessive back-flow Through Return Line Check Valve Was Noted.Check Valve Were Declared Inoperable.Compensatory Actions for Fesw Sys Pipe Break Were Established.With
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
05000440/LER-1986-055, :on 860902,reactor Scram Occurred.Caused by Sudden Increase in Sensed Pressure for Steam Bypass Valves Controller.Pressure Regulators & Instrumentation Valve Lineups Recalibr,Procedures Revised & Mgt Directive Issued
05000413/LER-1998-017, :on 981015,TS SR on Standby Shutdown Sys Instrumentation Was Missed.Caused by Inadequate Change Mgt Process.Calibrated Affected Resistance Temp Detectors & Modified Procedure.With
05000423/LER-1999-003-01, :on 990505,identified That 18 Month EDG Surveillance Test for LOP with ESF Start Did Not Initiate Test.Caused by Inadequate Understanding of Regulatory Guidance. a & B EDG Returned to Status.With
05000289/LER-1998-008-01, :on 980818,RM RM-A-8G-High Was Noted Inoperable for More than 7 Days.Caused by Weaknesses in I&C Work Practices.Revised Data Collection Portion of Surveillance Procedures
05000382/LER-1997-006, :on 970221,discovered Void at Penetration 39 During Ultrasonic Testing of Lpsi.Caused by TS 4.5.2j Not Being Completed post-maint.Invoked TS Requirement Surveillance 4.0.3 to Complete TS 4.5.2j
05000382/LER-1997-002, :on 970130,72 H Administrative Action Statement Entered Due to Declaring Shutdown Cooling HX B Inlet & Outlet Valves SI-125B & SI-412B Inoperable.Valves Declared Operable After Installation of Relief Devices
05000213/LER-1996-025, :on 960927,spent Fuel Building Air Filtration Sys Failed Air Flow Test.Caused by Failure to Recognize Coincident Operation of Pab & Sfb Effect on Air Flow Test. Adjusted Cleanup Sys Damper
05000213/LER-1997-001, :on 970114,river Temperature Below UFSAR Analyzed Condition Occurred.Caused by Design Basis Calculations Were Not Updated in a Timely Manner.Ufsar & Design Basis Calculations Will Be Revised
05000370/LER-1985-029-02, :on 851110,turbine-driven Auxiliary Feedwater Pump Automatically Started from Loss of Nonessential Power. Caused by Blown Fuse in auto-start Circuitry.Fuse Replaced & Auxiliary Feedwater Pump Secured
05000382/LER-1997-008, :on 880419,discovered Incorrect Quantity of Tri-Sodium Phospate Used for ECCS Ph Determination.Caused by Personnel Error.Generated Corrective Action Document & Verified post-1988 Similar Surveillances
05000382/LER-1997-005, :on 890715,failure to Perform Coolant Low Flow Trip Operating Bypass Surveillance Occurred.Caused by Failure to Implement Procedural Controls to Test Reactor Coolant Low Flow Bypass.Event Will Be Reviewed
05000289/LER-1997-001-02, :on 970117,potential Overpressurization of Piping Between Closed Reactor Building Containment Isolation Valves Occurred Due to Inadequate Design Code Guidance. Results of Review Will Be Documented.Pages 2 & 3 Corrected
05000382/LER-1997-003, :on 970130,process Analog Computer Card Failed on Essential Services Chilled Water Train B.Caused by Open Fuse on Process Analog Control.New Pac Card Installed & Calibrated
05000445/LER-1996-008, :on 961017,two Pressurizer Safety Valves Were Found with Unsatisfactory Lift Setpoints.Caused by Setpoint Drift.Valves Were Returned to Operable Status Using Normal Rework for Components
05000354/LER-1996-027-01, :on 961202,ESF Actuation & Unplanned Automatic Start of Safety Auxiliaries Cooling Sys Pump a Occurred Due to Personnel Error.Nco Involved in Event Counseled
05000461/LER-1996-019, :on 961120,inadequate Surveillance Procedures Were Noted Due to Misinterpretation of TS Bases Results in Source Range Monitor Reactor Period Display Not Verified. Procedures CPS 9031.13 Will Be Revised
05000528/LER-1985-030, :on 850425,both ECCS Trains Declared Inoperable Due to Indeterminate Operability of Containment Recirculation Sump Isolation Check Valves.Caused by Failure to Retest Valves Following Disassembly
05000293/LER-1996-005, :on 960419,automatic Scram Occurred Due to Turbine Vibration During Planned Power Reduction.Turbine Vibration Trip Setting That Initiates Trip of Turbine Due to High Vibration Changed
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
05000348/LER-1996-002-01, :on 960529,TS Surveillance Requirements Not Met & common-cause Failure Identified.Caused by Personnel Error. Revised Surveillance Test Procedures & Modified Underfrequency Reactor Trip Circuits
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
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
05000373/LER-1996-001-06, :on 960213,missed TS Required Fire Protection Valve Position Verification Occurred.Caused by Human Performance.Operating Dept Senior Mgt Reinforced Expectations W/Sros & Shift Supervisors
05000446/LER-1996-002, :on 960126,noted That TS Surveillance for Turbine Overspeed Missed Due to Oversight in Rescheduling Required Surveillance by Cognizant Personnel.Test Completed on 960126 & Event Reviewed as Lesson Learned
05000369/LER-1985-005-01, :on 850201,determined Plant Outside Design Analyses Assumptions,Based on Westinghouse Response Re Negative Flux Rate Trip Setpoint.Bistable Setpoint Reduced to 2.5% Rated Thermal Power
05000382/LER-1996-001-02, :on 960111,entered TS 3.0.3 Due to SIT Levels Reading High.Cr Staff Immediately Lowered SIT Levels Until within Specified Ranges for Compliance W/Ts
05000446/LER-1996-001, :on 960107,allowed Outage Time Was Exceeded in Conjunction W/Enforcement Discretion for RCS Instrument Channel.Caused by Action Statement Requirements Not Being Met
05000354/LER-1995-040, :on 951218,EDG B Inadvertently Started Due to Improper Removal from Svc.Caused by Lack of Questioning Attitude by Operations Personnel.Addressed Communications Issues & Made Procedural Revs
05000382/LER-1995-006-04, :on 951207,failed to Provide Backup Overcurrent Protection Due to Personnel Error.Installed Backup Overcurrent Protection for Circuits & Tested Two Breakers
05000354/LER-1995-029, :on 951102,both Trains of Standby Liquid Control Declared Inoperable Due to Failure to Perform Surveillance Per IST Requirements.Audit Team Performed in- Depth Review of Sys
05000354/LER-1995-020, :on 950908,automatic Actuation of HPCI Suction Path Swapover ESF Occurred.Caused by Absence of Realistic Operating Band Considering Loop Inaccuracies.Incorporated Realistic Band Into Operations Procedures
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
05000318/LER-1984-005, :on 840426,diesel Generators 12 & 21 Inoperable Simultaneously.Caused by Personnel Error.List of Equipment Required to Maintain Diesel Generator Operability Prepared & Operators Will Be Trained on Event Condition
05000317/LER-1995-001-01, :on 950415,Unit 1 Entered TS 3.0.3 When EDG Supplying Backup Power Became Inoperable.Caused by Leaking Fuel Injector Pump Due to Improper Drainage.Drain Lines Cleaned
05000458/LER-1995-005-02, :on 950627,HPCS Pump Breaker Tripped During Surveillance Testing.Cause of Failure Not Identified.Breaker Internals,Prop Springs & Closing Latch Spring Inspected.W/
05000423/LER-1994-014-02, :on 941121,TDAFWP Failed to Start During Cold Start Surveillance Test.Caused by Preexisting Conditions of Tdafwp Trip Valve Linkage.Corrective Maintenance Performed on Linkage
05000285/LER-1993-018, :on 931206,reactor Trip Occurred Due to Turbine Trip on Low Hydraulic Fluid Pressure.Caused by Inadequate Design of ECN 93-162.Configuration of EHC Sys Tubing Corrected
05000285/LER-1993-012, :on 930923,identified Condition Involving Five MOVs Having Cables That Were Inadequately Sized Due to Lack of Attention to Detail in Design Package Preparation for 1990 Mod.Thermal Overloads Enabled
05000285/LER-1993-016, :on 931113,CEA Withdrew from Reactor Core & Rod 31 Became Fully Withdrawn.Caused by Lack of Ground Detection Sys for Associated Power Supplies.Ground Detection for CRD Power Supply Installed
05000410/LER-1987-025, :on 870519,secondary Containment Isolation Signal Generated Due to Technician Relanding Lifted Lead Prematurely.Caused by Breakdown in Communications.Gaitronics Phone &/Or Headset Jack Installed
05000296/LER-1989-003-03, :on 890307,reactor Protection Sys Channel a half-scram & Actuation of Standby Gas Treatment Sys Occurred When Circuit Protectors Momentarily Tripped.Caused by Voltage Transient.Signals Reset
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
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
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
05000397/LER-1989-031, :on 890806,low Reactor Pressure Vessel Level Reactor Scram Initiated by Reactor Protective Sys in Response to Actual Low Water Level Condition Caused Unplanned Trip of Reactor Feedwater Pump 1B
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-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-1988-012, :on 880606,potential Existence of Unmonitored Radiological Effluent Release Path During Certain Emergency Conditions Determined.Cause Unknown.Fan Disabled.Part 21 Related
05000237/LER-2009-004, Shutdown Cooling System Isolation During Cooldown Due to Temperature Instrumentation Failure
05000302/LER-1998-004, :on 980212,unanalyzed cross-connecting of 480 Volt Busses Was Noted.Caused by Inadequate Design Controls. Administrative Controls Will Remain in Place
05000498/LER-1999-002-01, :on 990327,inadequate Performance of TS Surveillance When Evaluating Source Range Nuclear Instrument Discriminator Bias Curve Results,Was Discovered.Caused by Lack of Process to Incorporate Info.Compared Bias Curves