05000400/LER-1995-005-02, :on 950731,TS Violation Occurred Due to Missed Compensatory Vent Stack Flow Rate Estimate.Counseled Individual Involved & Training for Appropriate Operations Personnel Will Be Performed
05000400/LER-1997-014, :on 970514,SI Occurred During Ssps Surveillance Testing.Caused by Inattention to Detail During Recent Rev to Surveillance Test Procedure Being Used.Revised Deficient Surveillance Procedures
05000400/LER-1997-006, :on 970318,breach Was Identified in Thermo-Lag Fire Barrier Wall Due to Inadequate Initial Design,Poor Construction Methods & Incomplete as-built Design.Visual Insp of Thermo-Lag Barrier Walls Performed
05000400/LER-1998-005, :on 980420,TS Verbatim non-compliance Was Determined.Caused by Misinterpretation of TS Requirements. Issued Memo to Reemphasize Need to Comply W/Literal Meaning of TS Requirements in Verbatim Manner
05000400/LER-1995-008-01, :on 950902,charging/SI Pump B (Csip) Returned to Svc Prior to Required Acceptance Testing.Caused by Personnel Error.Csip a Placed in Svc on 950902 & Csip B Declared Inoperable
05000400/LER-1996-012, :on 960724,SIII Inverter Was Taken OOS for Repair.Caused by Faulty ferro-resonant Transformer within Inverters Internal Circuitry.Repairs & Load Testing for Siii Were Completed
05000400/LER-1995-007-01, :on 950901,inadvertent Start of Turbine Driven AFW Pump/Unplanned ESF Actuation Occurred Due to Inadequate Test Procedures.Revised Appropriate Procedures
05000400/LER-1997-002, :on 970207,determined That Cold Weather Conditions Resulted in Mfiv Being Potentially Inoperable During Period 970117-20.Caused by Inadequate Design of HVAC Sys.Implemented Mods to Steam Tunnel HVAC Sys
05000400/LER-1998-006, :on 980508,failure to Perform Insp & Preventive Maint on MCCB as Required by TS Was Noted.Caused by Inadequate Sps.Tested 9 Pressurizer Heater Bank Breakers by Cycling Each
05000400/LER-1997-020, :on 970814,inadequate Fire Protection Provided for safety-related EDG Fuel Oil Transfer Pump Cables Resulted in Operation Outside Design Basis.Caused by Engineering Oversight.Established Fire Watches
05000400/LER-1998-002, :on 980121,determined Ssps (P-11 Permissive) Testing Deficiency.Caused by Inadequate Review of Initial Ts.Will Revise & Perform Surveillance Test Procedures to Verify Operability of P-11 Permissive
05000400/LER-1997-012, :on 970505,determined That Previous Auxiliary Control Panel Had Not Verified Operability of Interposing Relays.Caused by Misinterpretation of Tss.Reviewed Other Remote Shutdown Panel Transfer Circuitry
05000400/LER-1997-021, :on 980210,discovered That SFP Water Level Had Not Been Verified Greater than 23 Feet Above BWR Fuel Assemblies.Caused by Misinterpretation of TS Requirements. Will Submit TS Change Request to Revise TS 3.9.1.11
05000400/LER-1997-015, :on 970602,inadequate Auxiliary Feedwater Sys Flow Control Valve Surveillance Testing Deficiency Was Identified.Caused by Failure to Recognize Impact on TS 4.7.1.2.1.Readjusted AFW FCV Actuator Spring
05000400/LER-1997-010, :on 970418,design Deficiency Determined Re Reactor Coolant Pump Motor Oil Collection Sys.Caused by RCP Ocs Design Detail.Rcp Ocs Enclosures for Each of Three Installed RCP Motors Have Been Modified
05000400/LER-1997-023, :on 920721,RCS PIV Testing Deficiency Was Noted.Caused by Failure to Consider All Testing Variables During Initial Sp Development.Surveillance Tp OST-1506 Was Revised to Incorporate Correction Factor
05000400/LER-1996-020, :on 960906,inadvertent RWST Boron Dilution Event Occurred.Caused by Personnel Error.Operating Procedure Was Revised to Reflect locked-closed Designation for RWST Fill Valve 1DW-5
05000400/LER-1997-022, :on 970829,TS Required Shutdown Due to Expiration of AFW Lco.Caused by Personnel Error.Completed Repairs TDAFW Pump & Returned Plant to Svc on 970831
05000400/LER-1996-025, :on 961218,determined Missed Surveillance Test on PORV Block Valve 1RC-115.Caused by Personnel Error.Tested 1RC-115 & Counseled Personnel Involve
05000400/LER-1997-001-01, :on 970131,automatic Reactor Tripped Resulting from SG low-low Level.Caused by Inadvertent Closure of Mfiv (1FW-159) & Faulty Hydraulic Relays.Shuttle Valves Replaced, SG Level Discrepancy Investigated
05000400/LER-1997-013, :on 970508,entry Into Mode-6 Without Operable Components,Resulting in TS 3.0.4 Violation Occurred.Caused by Personnel Error.Personnel Involved Counseled
05000400/LER-1997-019, :on 970720,turbine Trip/Reactor Trip Occurred. Caused by Three Phase Fault That Collapsed Excitation Field in Main Generator,Resulting in Generator Lockout.Exciter Rotor Assembly Was Replaced
05000400/LER-1996-021, :on 961107,inadequate post-maint Testing Following Repairs on Containment Isolation Valve 1SP-208 Identified.Caused by Misinterpretation of ASME Code. Procedures Revised
05000400/LER-1997-024, :on 971118,SSPS Testing Deficiency Was Noted. Caused by Inadequate Testing Scheme Provided by Ssps Vendor. Revised Procedure
05000400/LER-1996-017, :on 960805,failure to Perform Surveillance Testing Required by TS Noted.Caused by Personnel Error. Surveillance Testing Scheduling Process Has Been Developed & Implemented on Trial Basis
05000400/LER-1997-008, :on 970404,safety-related AHU Not Declared Inoperable During Maintenance on Associated Temperature Switches Resulting in Violation of Ts.Caused by Incorrect Interpretation.Operations Night Order Issued
05000400/LER-1996-022, :on 961122,wiring Discrepancy Was Found in Auxiliary Building Ventilation Sys Circuitry.Caused by Personnel Error.Training on This Event Will Also Be Performed for Appropriate Maintenance
05000400/LER-1997-009, :on 970407,fuse Was Removed from CR Ventilation Isolation Signal Power Supply Circuitry Due to Personnel Error.Individuals Involved Were Counseled
05000400/LER-1996-009, :on 960530,identified Deficiencies in Reactor Auxiliary Bldg Exhaust Sys.Caused by Inadequate Surveillance Test Procedures.Revised Test Procedure
05000400/LER-1996-024, :on 961121,identified Common Mode Failure in RAB Electrical Equipment Protection Rooms Ventilation Sys. Caused by Inadequate Initial Sys Design.Will Install Plant Mod to Resolve AH-16 Single Failure
05000400/LER-1997-011, :on 970422,inappropriate TS Interpretation Resulted in Violations of ECCS Accumulator TS & Entry Into TS 3.0.3.Caused by Procedural Inadequacy.Tsi 88-001 Cancelled 970508 & Procedures Revised
05000400/LER-1996-016, :on 960814,reactor Trip Bypass Breaker Surveillance Test,Required by TSs Not Performed.Caused by Inadequate Procedures Not Ensuring Testing Done Prior to Placing Them in Svc.Procedures Revised
05000400/LER-1997-017, :on 970612,failed to Recognize Inoperable Reactor Afd Monitor.Caused by Personnel Error.Operators Involved in Event Will Be Counseled Prior to Assuming Shift Duties
05000400/LER-1998-003, :on 980129,failure to Perform Shutdown Margin Calculation Required by TS Surveillance Requirements Occurred.Caused by Ambiguity in TS 3.1.3.1.c.Procedures Revised
05000400/LER-1996-002-04, :on 960508,failed to Properly Perform Tech Spec Surveillance Testing.Caused by Personnel Error.Personnel Counseled,Procedure Revised & Continued in-program Tech Spec Testing Program Review
05000400/LER-1996-008, :on 960425,turbine Trip/Reactor Trip Occurred. Caused by High Resistance Connection Resulting from a Phase Switch Jaw & Blade Contacts.Failed a Phase Disconnect Switch on Breaker 52-7 Replaced
05000400/LER-1996-005-01, :on 960312,failure to Properly Test Containment Bldg Outer Personnel Air Lock Door Occurred.Caused by Personnel Error.Individual Involved Counseled.W/Undated Ltr
05000400/LER-1996-003, :on 960122,failed to Perform Core Flux Mapping Following Short Power Excursions Over 100% Power.Caused by Amend 50 Being Incorporated W/O Properly Implementing TS Action Statement.Revised Associated TS Bases
05000400/LER-1995-014-01, :on 940424,RHR Sys Components Removed from Service as Directed During Testing,While Required for Operability.Caused by Procedure Inadequacies.Test Will Be Revised to Correct Procedure by 960215
05000400/LER-1998-001, :on 980109,potential Condition Outside Design Basis Related to Instrument Air Sys Leak Causing SG pre- Heater Bypass Isolation Valves to Be Inoperable Was Noted. Caused by Inadequate Design Control.Generated Jco 98-01
05000400/LER-1995-016-01, :on 951228,unplanned Esf/Rps Actuation Occurred Due to Unexpected Opening of a RT Breaker During Testing. Caused by Inadequate Procedure.Revised Procedure & Trained Appropriate Personnel
05000400/LER-1995-004-01, :on 950524,identified Possibility That Blown Fuse in Control Power Circuit Could Affect Hydraulic Pump. Caused by Discrepancy Between Circuit Wiring & Diagrams for Control Board Alarm.Drawing Review Completed
05000400/LER-1996-018, :on 960903,manual Reactor Trip Occurred Due to Loss of Normal Sw.Caused by Mechanical Failure of B Water Pump & a Normal SW to Remain Running Once Manually Started.Restored a Normal SW Pump to Svc
05000400/LER-1996-013, :on 961028,condition Outside of Design Basis Where RWST Had Been Aligned w/non-seismically Qualified Sys Was Identified.Caused by Failure to Reconcile Operating Procedure Lineups.Established Administrative Controls
05000400/LER-1994-007-02, :on 941128,violations of TS Min Control Room Staffing Requirements Occurred.Caused by Personnel Error. Individuals Involved Counseled & Received Disciplinary Measures
05000400/LER-1995-006, :on 950824,ECCS Sys Piping Was Not Fully Contained within RAB Emergency Exhaust Sys Boundary Resulted in Condition Outside Design Basis.Periodically Inspected Affected Piping for Leakage
05000400/LER-1995-006-01, :on 950824,determined Discrepancy Re Design of RAB EES Constituted Condition Outside Design Basis.Cause Still Under Investigation.Established Administrative Leakage Limit of 1 Gallon Per Hour
05000400/LER-1996-015, :on 960812,partial ESF Actuation of Main Steam Isolation Signal Occurred During Surveillance Testing Due to Operator Error.Sta Counseled
05000400/LER-1994-006-03, :on 941116,surveillance Testing Revealed That inter-cell Float Voltage for Cell 50 of B-SB Safety Related Battery Outside Allowable TS Limits Due to Deficient Maint Surveillance Test Procedure.Procedure Revised
05000400/LER-1994-003-01, :on 940718,improperly Analyzed Single Failure in Esws Occurred That Could Potentially Result in Charging/ Safety Injection Pumps Not Performing Safety Function.Caused by Inadequate Reviews.Review Conducted
05000400/LER-1994-005-02, :on 940901,TS Surveillance Violation Occurred. Caused by Personnel Error During Sample Analysis Process. Individuals Involved in Incident Counseled & Event Reviewed W/Applicable E&C Personnel
05000400/LER-1994-002-03, :on 940717,TS Surveillance Violation Occurred Due to Failure to Perform Required RMS Compensatory Measures for TB Wrgm,Declared Inoperable on 940716.Daily SR Procedures Will Be Revised
05000400/LER-1995-002, :on 950207,unanalyzed Condition Existed Re Potential of Loss of Automatic ESF Actuations & Subsequent TS 3.0.3 Entry.Caused by Both Trains of Ssps Declared Inoperable.Plant Evolutions Avoided
05000400/LER-1994-003-03, :on 940718,single Failure Identified in One Train of Esws That Could Possibly Prevent High Head Charging/Si Pumps from Performing Design Function.Caused by Oversight During Esws Design
05000400/LER-1995-001-02, :on 950119,determined That Deficiency Existed in Operability Verification Test for Thermal Overload Bypass Circuitry Due to Procedural Inadequacies.Review Performed of Applicable Surveillance Test Procedures
05000400/LER-1996-019, :on 960906,downed Power Lines & Trees Blocked Plant Access Roads Hampering Site Personnel from Accessing Plant.Caused by Passage of Hurricane Fran.Plant Roads Were Cleared on 960906 & Plant Restarted
05000400/LER-1993-007-01, :on 930523,SUT to Auxiliary Bus E Supply Breaker 121 Failed to Open Automatically Due to Misaligned Mechanism Operated Cell Switch in Breaker 122.Insp of Other 6.9 Kv Breakers Performed
05000400/LER-1995-012-01, :on 951110,containment pre-entry Purge Valve 1CP-1 Drifted Open During Mode-1 Power Operation.Caused by Inadequate Means to Ensure That Air Operated Valves Sealed Closed.Aligned Instrument Air Sys
05000400/LER-1993-004-02, :on 930413,discovered That Two CR Ventilation Dampers Not Tested within Required Surveillance Interval Due to Personnel Error.Operations Surveillance Test OST-1131 Revised & Event Reviewed by ISI Personnel
05000400/LER-1993-009-01, :on 930622,TS Violation Occurred Due to Axial Flux Difference Logging Error.Caused by Personnel Error. Individuals Involved Counseled & Afd Operations Surveillance Test OST-1070 Revised
05000400/LER-1993-001-03, :on 930308,discovered That Operations Surveillance Test for Onsite Power Distribution Did Not Check Position of Battery 2CB Input Breakers.Caused by Procedure Rev Oversight.Procedure Revised
05000400/LER-1997-003-01, :on 970227,steam Generator Low Level Protection Circuitry Outside Design Basis Occurred.Caused by Inadequate Failure Modes & Effects Analysis Performed as-built Piping Configuration for S/G Level.Review Performed
05000400/LER-1993-002-03, :on 930330,discovered Bearing Failure on Fan AH-92H Concurrent W/Inoperable Train B Essential Svc Chilled Water Chiller.Caused by Loose Bearings Shaft Locking Ring. Air Handling Unit Repaired & Returned to Svc
05000400/LER-1993-005-02, :on 930428,discoverd That Error Made During Review & Evaluation of Charging/Si Pump (Csip) B Acceptance Test Results.Caused by Personnel Error.Csip B Declared Inoperable
05000400/LER-1993-003, :on 930628,discovered Possible Design Deficiency in Containment Vacuum Relief Sys Due to Inconsistent Interpretation of Ts.Reduced Containment Vacuum Relief Automatic Actuation Setpoint
05000400/LER-1992-014, :on 921013,pipe Wall Thinning Identified in AFW & MFW Sys.Caused by Flow Accelerated Corrosion.Affected Piping Replaced.Addl Matl Upgrades or Sys Configuration Changes Will Be Considered
05000400/LER-1992-014-02, :on 921013,identified Excessive Pipe Wall Thinning in Portions of Main Feedwater & AFW Sys.Caused by pre-heater Bypass Vibration Mod.Piping That Exihibited Extensive Erosion Will Be Replaced
05000400/LER-1996-002-01, :on 960117,failure to Perform Required Surveillance Testing During Planned Maint Outage in Oct 1994 Identified.Caused by Personnel Error.Personnel Involved Counseled
05000400/LER-1994-001-03, :on 940502,discovered That Slave Relay Test for K623 Did Not Verify Actuation of RCDT Pumps Discharge Valve 1ED-121.Caused by Procedural Deficiency in OST-1044. Procedure OST-1044 Has Been Revised
05000400/LER-1995-011-01, :on 951105-06,reactor Trip/Si Signal Generated & Unplanned ESF Actuation Occurred During Troubleshooting. Reactor Trip Caused by Equipment Failure.Component Replaced
05000400/LER-1992-007-02, :on 920712,automatic Turbine Trip & Reactor Trip Occurred Due to Failure of Low Pressure Turbine Exhaust Boot Seal.Repairs to Low Pressure Turbine Exhaust Boot Seal Completed on 920713
05000400/LER-1992-005-02, :on 920527,WRGM Declared Inoperable & Removed from Svc Due to Personnel Error.Additional Training Provided for Personnel Involved
05000400/LER-1993-008-01, :on 930525,TS Violation Occurred Due to Improper Wiring in Containment Penetration Current Limiting Breaker.C/As:Breaker Satisfactorily Tested Per MST-E0006 on 930618
05000400/LER-1995-011, :on 951105,reactor Trip/Safety Injection Occurred During Solid State Protection Sys Testing Due to Failure of Relay Contact & Unplanned ESF Actuation Occurred During Troubleshooting
05000400/LER-1991-019, :on 911022,containment Ventilation Isolated Due to Spike on Radiation Monitor,Constituting Unplanned Actuation of ESF Component.Special Test Developed & Performed During Refueling Outage 4
05000400/LER-1992-013-02, :on 920822,discrepancy Noted in EDG Monthly Operability Test Performed on 920726.Caused by Personnel Error.Personnel Counseled,Event Reviewed W/Applicable Personnel & Testing Procedure Revised
05000400/LER-1992-003, :on 920128,discrepancy Discovered Involving Safety Injection Switch Overtime from Cold Leg to Hot Leg Recirculation.Caused by Inadequate Communication.Night Order Issued Re Recirculation Switchover
05000400/LER-1991-016-01, :on 910808,containment Cooling Water Pump B Started,Resulting in Momentary Pressure Spike Which Caused Three Relief Valves to Open.Caused by Error in Original Sys Design.Personnel Trained Re Valve Setting
05000400/LER-1991-017-01, :on 910827,tech Spec Violation Occurred Due to Missed Composite Sample During Release of Secondary Waste Sample Tank.Caused by Personnel Error.Verified That Effluent Stream Contained No Radioactivity
05000400/LER-1991-020-01, :on 911204,discovered Deficiency in Radiation Surveillance Test Used for Leak Testing Sealed Sources to Satisfy TS Requirements.Caused by Procedural Deficiency. Procedure Revised & Training Provided
05000400/LER-1992-008-02, :on 920713,reactor Tripped Due to lo-lo SG Level.Caused by Operator error.Post-event Debriefing Conducted W/Involved Operations Personnel Re Need for Attention to Detail
05000400/LER-1992-010-02, :on 920717,automatic Turbine Trip & Reactor Trip Occurred Due to Loss of Condenser Vacuum.Caused by Failure of North Low Pressure Turbine Exhaust Boot Seal. Replacement of Boot Seals Completed on 920721
05000400/LER-1991-021-01, :on 911218,error Discovered in Program Utilized to Determine Containment Sump in-leakage Flow Rate.Caused by Personnel Error During Computer Design Development.Erroneous Error Corrected & Event Reviewed
05000400/LER-1991-006-01, :on 910319,shutdown Margin Requirements Not Verified During Surveillance Testing on source-range Nuclear Instruments.Caused by Misinterpretation of Tech Specs.Procedures Will Be Revised
05000400/LER-1992-009-02, :on 920715,manual Reactor Trip/Afw Actuation Occurred Due to Low SG Level.Caused by Inadvertent Deenergization of MFP Recirculation Valve Power Supply. Supply Breaker Replaced
05000400/LER-1991-012-01, :on 910515,unplanned Actuation of Auxiliary Feedwater Sys Occurred.Caused by Failure of Main Feed Pump a to Start.Investigation & Testing Performed on Pump & Associated Circuitry
05000400/LER-1991-005-01, :on 910313,Tech Spec 3.0.3 Entered Due to Failed Performance Test on Emergency Sequencer B While Csip a Inoperable.Caused by Isolated Contact Failure in B Program Relay.Faulty Relay Replaced
05000400/LER-1991-004-01, :on 910314,train B Essential Svc Chilled Water Sys Inoperable Due to Unsatisfactory Performance Test Results.Caused by Inability to Verify Check Valve Had Closed.Procedure OPT-1512 Revised
05000400/LER-1991-019-01, :on 911022,containment Ventilation Isolation Signal Generated,Resulting in Unplanned Actuation of ESF Component.Caused by Spike on Three Radiation Monitors.Power Supply Circuitry Repaired & Adjusted
05000400/LER-1991-009-01, :on 910521,AFW Actuation Occurred Due to Steam Generator Hi-Hi Level Alarm Inadvertently Generated During Troubleshooting.Caused by Personnel Error.Technicians Counseled & Addl Procedural Guidance Developed
05000400/LER-1990-025-01, :on 901206,max Allowable Leak Rate for Containment Bldg Pal Exceeded,Per TS 3.6.1.3.b,resulting in Cooldown.Caused by Component Wear.Repairs/Adjustments Performed
05000400/LER-1990-022-01, :on 901108,missed Surveillance Test for Secondary Waste Sample Tank Due to Incorrect Procedure Rev
05000400/LER-1990-024, :on 901121,64 Bussman Fnm Type Fuses in 125- Volt safety-related Applications Found Unacceptable.Caused by Recent Downgrade in Fuse Performance Specs Provided by Vendor.Fuses Replaced,Per Plant Mod PCR-5549
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-1995-003-01, :on 950518,deficiency Identified in Testing Method for Cooling Water Supply Valves for ESW Intake Structure.Caused by Deficient TS Sps.Surveillance Test Procedures OST-1214 & OST-1215 Revised
05000400/LER-1992-002-02, :on 920119,problems Encountered W/Plant Process Computer.Caused by Failure to Restart Program That Performs Sump Leak Rate Calculations & Data Transmission Error.Computer Sys Will Be Upgraded
05000400/LER-1991-015, :on 910519,AFW Actuation Occurred.Caused by Improperly Set Feed Flow Transmitter.Investigation, Adjustment & Successful Testing Performed to Restore Feed Flow Transmitter to Svc
05000400/LER-1991-003-01, :on 910121,missed Surveillance Test During Emergency Diesel Generator Fuel Oil Sampling.Caused by Personnel Error.Training Conducted for Chemistry Personnel & Procedure RST-209 Revised
05000400/LER-1992-012-02, :on 920802,one of Three Secondary Relays Failed to Actuate,Causing TS 3.0.3 to Be Entered.Caused by Failure of under-voltage Relay to Actuate.Procedure Will Be Revised to Provide Guidance for Tripped Condition