05000285/LER-1998-004, :on 980423,determined That Indication in Fort Calhoun Station SG Tube Had Been Identified During 1996 Exams,But Had Been Inadvertently Left in Svc.Caused by Personnel Error.Procedures Revised
05000482/LER-1987-025, :on 870623,ESFAS Initiated During Performance of Surveillance Test Procedure.Caused by Personnel Error. Surveillance Test Procedures Revised
05000458/LER-1997-004-02, :on 970724,inadequate Surveillance of Division III Battery Occurred Due to Calculation Error.Performed Revised Division III Battery Svc Discharge Test Procedure Using Correct Battery Profile
05000373/LER-1997-028, :on 970618,missed RHR Sys Increased Frequency Surveillance Resulted in Operation to Be Outside of TS Requirements Due to Personnel Error.Improved Procedures Governing Station Surveillances
05000328/LER-1986-004-04, :on 860922,incorrect Data Used in Executing Incore Computer Program.Caused by Personnel Error.Incore Corrected & Verified.Previous Informal Written Procedure for Installing Data & Software Formalized
05000362/LER-1986-013-01, :on 860904,reactor Tripped on Loss of Load When Power Supply to Turbine Protection Panel Momentarily Interrupted.Caused by Operator Error.Event Discussed During Shift Briefings W/Involved Personnel
05000361/LER-1986-030, :on 860911,core Protection Calculator Channel a Failed.Caused by Equipment Approaching End of Expected Life Cycle.Power Supply Replaced
05000529/LER-1986-027-01, :on 860531,turbine Trip Caused Actuation of Reactor Protection Sys,Initiating Reactor Trip.Caused by Personnel Error Due to Inadequate Procedures.Plant Operating Procedures Revised
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
05000499/LER-1997-007-01, :on 971121,manual Reactor Trip Occurred.Caused by Two Separate Failure Mechanisms That Combined to Result in Loss of Power to Cabinet.Failed Voltage to Pulse Converter Circuit Card Was Replaced
05000373/LER-1997-036, :on 971014,identified Error in Station Method of Accomplishing Channel Functional Test Requirements of TS 4.8.3.3.1.b.Caused by Personnel Error.Procedure Revised.W/
05000458/LER-1997-008-02, :on 971004,inadvertent Closure of RHR Shutdown Cooling Inboard Isolation Valve Occurred.Caused by Inadequate Administrative Controls,Supervision & Work Practices.Procedures Revised
05000333/LER-1997-013-01, :on 971216,high Pressure Coolant Sys Was Declared Inoperable.Caused by Instrument Malfunction During Surveillance Testing.Completed Repair Activities to Correct Adjustments to Master Trip Unit
05000373/LER-1997-016, :on 970414,rod Block Monitor Were Not Adequately Functionally Tested as Required by Ts.Caused by Inadequate Procedures.Affected Procedures Will Be Revised & Performed Prior to Plant Restart
05000366/LER-1997-003-02, :on 970328,excessive Leakage Identified on Secondary Bypass Valves Was Caused by Undersized Valve Operators & Inappropriate Valve & Operator Orientation. Re-routed Piping Containing Valves
05000461/LER-1997-008, :on 920408,determined That DG Undervoltage Relays Inoperable Due to Inadequate Process to Review Operability Requirements of Plant Equipment as Defined in Ts.Amend Requested to Change TS
05000245/LER-1997-001-02, :on 970110,liquid Radwaste Effluent Radiation Monitor Declared Inoperable Due to Leaking Automatic Isolation Valves.Valves Repaired
05000206/LER-1984-009-02, :on 841205,load Sequencer 31-day Surveillance Delinquent.Caused by Personnel Oversight.Personnel Counseled & Performance of Tech Spec Required Surveillances in Specified Manner Reemphasized
05000338/LER-1996-006-01, :on 961003,charging Pump Interlock Logic Renders Pumps Inoperable.Caused by Design Error.Action Statement Was Entered on Both Units to Prevent Susceptable Pump line-up
05000374/LER-1996-004-08, :on 960731,TS Fire Watch Was Missed Due to Incomplete Fire Impairment Permit.Caused by Human Error in Preparation of OOS for Inverter.Informed OOS & Fire Impairment Preparers of Event
05000457/LER-1996-005-05, :on 960506,inadventent Start of 2A Auxiliary Feed Water Pump Occurred.Caused by Personnel Error.Personnel Involved Counselled & Procedures Revised
05000285/LER-1996-004, :on 960315,discovered Adequate Shutdown Margin Was Not Maintained.Caused by Inadequate Technical Review by Plant Personnel Involved in Reviewing Procedure Change. Appropriate Personnel Trained on Incident
05000362/LER-1985-001-02, :on 850127,RCS Water Inventory Balance Indicated 2.97 Gpm Leakage Rate,Exceeding 1.0 Gpm Limit.On 850128,containment Purge Isolation Sys Train a Actuated from Airborne Iodine Resulting from Leak
05000301/LER-1995-006-01, :on 951125,PORV post-maint Testing Was Not Performed Prior to Establishing Ltop.Caused by Inadequate Control of post-maint Testing.Established TS Compliance by Venting RCS
05000354/LER-1995-026-01, :on 951026,RMCS Found in locked-up Condition Causing Entry of LCO Action Statement.Caused by Failure to Maintain Power Supply within Required Tolerances. Investigation Continuing
05000361/LER-1984-052, :on 840903,06 & 11,spurious Toxic Gas Isolation Sys on Trains a & B Actuated,Respectively.Caused by Overly Conservative Alarm Setpoints.Sys Instrumented W/Recorders to Determine Which Analyzer Caused Trip
05000281/LER-1983-054-03, /03L-0:on 831118,at Full Power,Emergency Diesel Output Breaker 3 Inadvertently Tagged Out.Caused by Personnel Error.Breaker 25J3 Racked In.Operator Disciplined
05000260/LER-1983-057-03, /03L-0:on 830923,while Performing S.I.4.9.A.4.b, Undervoltage Start of Diesel Generator,Diesel Generator 1A Oversped & Tripped.Caused by Electronic Governor Inhibited by Logic Breaker Malfunction
05000457/LER-1995-002-06, :on 950215,identified That Suction & Return Sensing Lines to Monitor Not Connected to Monitor.Caused by Procedural Deficiency & Personnel Error.Rev Made to ILRT Procedure & Personnel Counselled/Trained
05000366/LER-1994-002-01, :on 940301,during Monthly Operability Test of HPCI Thrust Bearing Temp Increased to 437 F & Decreased Below 200 F.Caused by Mfg Error in Thrust Bearing Housing. Failed Bearing & Gear Coupling Replaced
05000369/LER-1993-011, :on 931115,determined That DG 1B Fuel Storage Tank Level Gauge Out of Tolerence Due to Malfuntion of Subj Gauge.Iae Technician Calibrated Level Gauge to Bring Gauge Back Into Tolerence
05000267/LER-1982-012-03, /03L-0:on 820410,at 10% Power,Instrument Air Compressor 1C Temporarily Taken Out of Svc to Repair after- Cooler Leak.Water Leak Caused by Normal Wear of after- Cooler.Air Compressor Returned to Svc After Repairs
05000269/LER-1982-018-01, /01T-0:on 821014,three of Six Installed Safety Valves Determined to Have Degraded Performance Based on Valve Ring Settings.Cause of Difference in Ring Settings Unknown.Valves Reset Using EPRI Tested Settings
05000270/LER-1982-011-03, /03L-0:on 820822,erratic Indication Observed on Channel a Borated Water Storage Tank Level Instrumentation. Caused by Boiling Water in Level Transmitter Line.Heat Tracing Disconnected & Transmitter Lines Refilled
05000318/LER-1978-030-03, /03L-0 on 780828:discovered Control Element Assembly Motion Inhibit Not Operable for Position Deviation. Caused by Bad K2 Relay on Relay Card.Relay Replaced & Motion Inhibit Returned to Svc
05000315/LER-1992-004-01, :on 920420,7-day Test to Prove Operability of Boration Flow Paths from Refueling Water Storage & Boric Acid Storage Tanks Not Performed as Scheduled.Caused by Personnel Error.Test Successfully Performed