05000266/LER-1997-038, :on 970926,determined That Inoperability of Standby Emergency Power Placed Unit 2 in 7-day Lco.Caused by Failure That Occurred When EDG G-03 Was Shutdown.Repaired Governor & Returned EDG G-03 to Service
05000327/LER-1986-041, :on 860914,power Inadvertently Removed from Logic Relay Panel for Shutdown Board 2B-B,starting Standby Diesel Generators.Caused by Procedural Inadequacy.Diesel Generators Shut Down
05000328/LER-1987-006-02, :on 870518,discovered Error in Core Cycle Exposure & Height Dependent Power Factor.Caused by Personnel Error in Utilization of Vendor Supplied Data.Qa Qualification of Incore Will Validate Program
05000395/LER-1987-010, :on 870512,svc Water Screen Pump Failed to Start During ESF Loading Sequencer (Esfls) Testing.Caused by Defective Lug Crimp on Internal Vendor Wiring in Esfls Panel.Internal Wiring of Esfls Panels Reworked
05000327/LER-1986-048, :on 860820,during Review of Plant Surveillance Instructions,Adequacy of SI-260.2, Bit Cold Leg... Questioned.On 861016,CCP 2A-A Failed to Meet Acceptance Criteria.Caused by Inadequate Procedure
05000250/LER-1986-039, :on 861227,reactor Tripped Following Loss of Turbine Electrical Load Due to Failed Turbine Governor Control Oil Pressure.Turbine Control Oil,Lube Oil & Seal Oil Piping Will Be Cleaned
05000312/LER-1986-012, :on 860606 & 09,while in Cold Shutdown,Two Snubbers Removed from Operating Decay Heat Sys.Caused by Personnel Error.Snubbers Reinstalled & Planned Work on Snubbers Delayed Until Decay Heat Sys Outage
05000410/LER-1986-026-01, :on 861229,discovered That Conduit Seals Inside Manhole 6 Did Not Meet Internal Flooding Criteria.Caused by Design Deficiency.Two Covers to Manhole 5 Redesigned.Part 21 Rept Issued on 8701223
05000296/LER-1986-010-03, :on 860919,inadvertent Secondary Containment Isolations Occurred.Caused by Radiation Monitor Spiking High.Detector & Converter Unit Replaced
05000249/LER-1986-012-07, :on 860902,reactor Manually Scrammed Due to Large Number of Accumulator Alarms.Caused by Trip of CRD Pump 3B on Low Suction Pressure.Backup Pump Out of Svc for Repair.Procedure Dts 300-1 Changed
05000346/LER-1987-004, :on 870112,auxiliary Feedwater Train 1 Declared Inoperable.Caused by Failure to Evaluate Effects of Main Steam Sys Chemistry on Installed Diaphragms.Three Layer Pressure Switch Diaphragm Matl Replaced
05000382/LER-1986-018, :on 860903,seismically Unqualified Power Supply Panel for Hydrogen Recombiner Discovered.Caused by Absence of Structural Weld.Outside Foundation Weld Installed.W/
05000315/LER-1986-002-01, :on 860217,two Reactor Trip Sys Interlock Setpoints Found Out of Compliance W/Tech Spec Definitions. Caused by Misinterpretation of Tech Spec Requirements.Tech Spec Rev Under Consideration
05000382/LER-1986-016, :on 860804 & 21,boron Concentration for Safety Injection Tanks Fell Below Tech Spec Limit.Caused by Insufficient Procedural Requirements.Procedure Change Will Be Made to Prevent Recurrence
05000370/LER-1986-009-04, :on 860623,ESF Train a Feedwater Isolation Signal Actuated During Reactor Trip Breaker Testing.Caused by Defective Procedure.Isolation Valves Reopened.Procedures Will Be Revised.Personnel Will Review Event
05000370/LER-1986-010-03, :on 860623,refueling Water Storage Tank Declared Inoperable Per Tech Spec 3.5.3.d Due to High Temp. Caused by Mgt Deficiency.Procedure Will Be Written for Calibr of Operator Aid Computer Point for Temp
05000259/LER-1985-012, :on 850405,deficiency in Standby Gas Treatment Cable Routing Discovered.Caused by Drawing Design Error. Junction Box Remounted to Meet Seismic Criteria & Design Personnel Counseled
05000369/LER-1987-004-03, :on 870218,reactor Tripped Due to Low RCS Flow. Caused by Failed Surge Capacitor Resulting in Reactor Coolant Pump Motor 1C Tripping on Ground Fault.Surge Capacitor Replaced
05000260/LER-1986-005-02, :on 860403,primary Containment Isolation Occurred.Caused by Insecure Jumper Connections Across Relay & Hampered Relay Access During Surveillance Instruction. Interim Measure Eliminates Jumper Placement
05000414/LER-1986-002-05, :on 860413,containment Air Release & Addition Sys Release Terminated by Actuation of High Radiation Alarm. Caused by Generic Electrical Noise from Vacuum Switches. Alarm Reset.Grab Sample Taken
05000440/LER-1988-015, :on 880430,reactor Scram Occurred Due to Reactor Water Level of Less than Level 3.Caused by Procedural Deficiency.Operating Procedure Revised,Operators Involved Counseled & Operators Trained Re Events Sequence
05000327/LER-1986-005-01, :on 860218,0301 & 05,fire Watch Could Not Enter Applicable Rooms to Check for Fires Due to Inoperable Fire Doors.Caused by Faulty Screw.On 860303,fire Watch Not Initiated Due to Personnel Error
05000382/LER-1985-022, :on 850524,automatic Actuation of Reactor Protective Sys Occurred.Caused by Lack of Pressure Equalization Across Main Valve Piston.Valves Stroked at Cold Conditions
05000270/LER-1985-003-02, :on 850421,during Power Escalation After Zero Power Physics Testing,Control Rods Positioned Beyond Tech Spec Rod Position Index Limit Curve.Caused by Personnel Error.Boration of RCS Started
05000295/LER-1985-004, :on 850124,during Sump Valve Stroke Test PT-2B, Valves 1MOV-SI8812 a & B Failed to Reopen After Being Stroked Closed.Caused by Too Short Bypass Circuit Time.Time Reset & Tested
05000295/LER-1984-040-03, :on 850523,discovered That 840802 Initial Quarterly Channel Functional Test of Containment Sping Radiation Monitor 1RIA-PR40 Not Performed.Caused by Miscommunication Re Scope of Commitment
05000213/LER-1985-012, :on 850520,Tech Spec Surveillance Frequency Requirement Not Met in Performance of Rev 2 to Procedure SUR-5.5-26, Periodic Channel Functional Test of Reactor Coolant Pump Heat Detectors
05000296/LER-1985-014-02, :on 850429,Group 6 Containment Isolation Logic Inadvertently Initiated.Caused When RI-90-142 Taken to Zero Position to Check Recorder Reading.Containment Isolation Signal Reset
05000370/LER-1985-012-02, :on 850508,during Attempt to Swap Main Feedwater Pump 2A from Auxiliary to Main Steam Supply,Pump Tripped on High Discharge Pressure.Caused by Control Sys Not Responding to Speed Controller
05000413/LER-1985-023, :on 850329,reactor Power Exceeded 75% W/Only Two of Three Test Runs for Reactor Coolant Sys Performed. Caused by Software Problem.Thermal Output Calculations Program Modified,Reassembled & Reimplemented
05000382/LER-1985-010, :on 850321 & 22,unit Changed Modes After Two Reactor Trips W/Inoperable Hydrogen Analyzer & Subsequent Surveillance on ex-core Nuclear Instrumentation Not Performed.Caused by Loss of Feedwater Flow
05000366/LER-1985-009-01, :on 850319,RCIC Steam Supply Primary Containment Inboard Isolation Valve 2E51-F007 Inadvertently Closed.Caused by Personnel Error.Isolation Logic Reset & Valve Returned to Open Position
05000327/LER-1984-074, :on 841218,interactions Found That Were Not in Compliance W/App R of 10CFR50.Schedule for Corrective Actions Will Be Submitted by 850101.Fire Watches Will Continue Until Compliance Achieved
05000275/LER-1984-032, :on 841205,inadvertent Reactor Trip Occurred While Shutting Down Turbine for Maint.Caused by Personnel Error.Turbine Power Permissive P-13 Will Be Reset Using Actual Plant Data
05000413/LER-1984-025-03, :on 841127,motor Driven Auxiliary Feedwater Pumps Started After Loss of Main Feedwater Pumps When Reactor Trip Breakers Opened to Support Rod Drop Timing Test.Caused by Personnel Error
05000327/LER-1984-067, :on 841022,listed safety-related Sys Interactions Found Not in Compliance W/App R of 10CFR50.Fire Watches Established.Implementation Schedule for Corrective Actions Will Be Submitted by 850101
05000346/LER-1985-002, :on 850115,anticipatory Reactor Trip Sys Deenergized Control Rods During Performance of Zero Power Physics Testing.Caused by Steam Generator Level Decreasing to Low Steam Generator Trip Setpoint
05000370/LER-1984-034, :on 841221,reactor Actuation Occurred When Inverter Erroneously Removed from Svc.Caused by Operator Failing to Properly Identify Component to Be Removed from Svc.Personnel Counseled.Trip Setpoints Reset
05000287/LER-1984-006-03, :on 841106,offgas Monitors from Condensate Steam Air Injectors Showed Rapid Increase in Radiation Count Rate.Caused by primary-to-secondary Coolant Leak.Reactor Shutdown,Tests Run & Tubes Plugged
05000281/LER-1984-003, :on 840114,while at 23% Power,Feed Flow to Steam Generator a Increased to Full Flow.Valve Opened & Steam Generator a High Level Trip Initiated Turbine Trip, Tripping Reactor.Caused by Air Supply Piping Damage
05000331/LER-1993-007, :on 930921,unexpected Shutdown Cooling Isolation Occurred Due to Procedural Inadequacies.Reopened Valve & Revised Procedure
05000250/LER-1987-014, :on 870519,while Unit in Mode 6,determined That Design Discrepancy Existed in Containment Spray Sys.Caused by Flow Orifice in Discharge Line Not Incorporated in Field. Design Mods Will Be Implemented for Correction
05000250/LER-1988-014, :on 880714,RCS Leakage Surveillance Not Performed within Required Interval Due to Personnel Error. Note Placed in Night Book Stressing Need to Meet 18-30 H Tech Specs Requirements
05000315/LER-1991-007-01, Revised LER 91-007-01:on 910819,control Bank a Ordered Into Core by Rod Control Sys But Appeared Not to Move Into Core by Observation of Analog Rod Position Indication.Caused by Multiplexing Relay MXR-1 in Power Cabinet 2AC
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
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
05000397/LER-1989-005, :on 890311,34 of 185 Control Rods Drifted Inward from One to Seven Notches.Caused by Main Steam Line Radiation Monitor Design Deficiency.Desired Rod Pattern Reestablished
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-1987-006, :on 870426,after Shutdown Margin Demonstration, Reactor Protection Sys Tripped When Last Shorting Link Improperly Installed.Cause Determined to Be design-related. Terminal Strip Arrangement Will Be Evaluated
05000369/LER-1986-007-01, :on 860325,reactor Tripped on Steam Generator Lb lo-lo Level Signal.Caused by Failure of Bussman Fuses. Indicating Fuses Will Be Replaced W/Nonindicating Fuses
05000281/LER-1984-018-02, :on 841211,spurious Reactor Trip Occurred. Caused by 2 of 3 Logic Matrix for High Pressurizer Level Actuating.Addl Administrative Controls for Work on Energized Components Initiated