05000280/LER-1975-015, Updated LER 75-15/01T:on 750803,leaking Fitting on Overhead Gas Compressor B Resulted in Unplanned Release of Radioctive Matl from Site.Caused by Loose Fitting.Leaking Fitting Repaired
05000281/LER-1976-015, Updated LER 76-15/03L:on 761006,leakage of Water Observed from Recirculation Spray HX a Piping.Caused by Cracking in Heat Affected Zones of Several Welds.Listed Piping Will Be Replaced
05000237/LER-1950-237, Updated LER 50-237/75-048:on 751007,through-wall Crack Found in Drywell/Torus Nitrogen Purge Line 1604-18.Addl Mods, Including Temp Controlled Isolation Valve Installation, Delayed Until Proposal Review
05000000/LER-1975-005, :on 750127,analysis of Reactor Bldg Vent & Main Stack Charcoal & Particulate Filters Revealed Release Rates of Halogens & Particulates w/half-lives Greater than 8 Days, Exceeding Tech Spec Limits by 24%
05000263/LER-1983-006-01, /01T-0:on 830408,HPCI Woodward Governor Egr Hydraulic Actuator Coil Tailed.Caused by Lead Wire Insulation Degradation Allowing Ground Fault to Egr Housing. Egr Replaced.Hpci Satisfactorily Tested
05000295/LER-1978-094-03, /03L-0 on 780914:on a Phase a isolation,1FCV-PR24B & 1FCV-WD17A Failed to Close Placing Containment Isolation Sys in Degraded Mode.Caused by Asco 8320 Solenoid Valve Failing to Close Due to Oil in Instru Air
05000270/LER-1983-002-03, Computer Became Inoperable Causing Loss of Both RCS Subcooling Monitors. Caused by Deficiency in Installation Procedures.Computer Repaired & Restarted
05000263/LER-1977-012, :on 770620,GE Observed That Pump Trip Delay Time Assumed in Original Cycle 5 Transient Analysis Inappropriate.License Amend Request Will Be Submitted to Increase MCPR Transient Limits
05000263/LER-1977-009, :on 770531,main & Limit Switch Gear Train Grease Had Deteriorated Due to High Ambient Temp.Gear Train Cleaned & Repacked & Lower Temp Presently Maintained Due to Recent Ventilation Mod
05000251/LER-1976-001-03, /03L:on 760130,channel 2 Overtemp delta-T Reactor Trip Setpoint Exceeded Tech Spec Limit by One Degree.Caused by Failure of Two Filter Capacitors in Signal Summator. Capacitors Replaced
05000250/LER-1976-010-03, /03L:on 761125,trip Setpoint of Steam Flow Comparator FC-3-484 Found to Be Nonconservative.Caused by Failure of Two Filter Capacitors on Printed Circuit Board. Capacitors to Be Replaced
05000251/LER-1976-002-01, /01T:on 760214,water Level in Refueling Water Storage Tank 1% Lower than Tech Spec Requirement.Caused by Poor Calibr Ability of Wide Range Indicator Gage.Narrow Range Gage Will Be Installed as Backup
05000250/LER-1976-006-01, /01T:on 760909,closing Springs in Diesel Generator 3A Circuit Breaker Not in Charged Position.Caused by Worn Nylon Bushing Between Closing Spring Drive Motor & Linkage to Ratchet Wheel
05000251/LER-1976-007-01, /01T:on 761002,diesel Generator a Engine Cooling Water Tank Level Found Low.Caused by Sample Valve Not Being Fully Closed After 761001 Water Sample.Valve Closed & Water Added
05000250/LER-1976-008-01, /01T:on 761006,boron Concentration of Injection Tank Below 20,000 Ppm Limit.Cause Undetermined.Shutdown Initiated
05000306/LER-1977-011, :on 770406,cooling Tower Bus CT12 Lost.Caused by Personnel Error.Personnel Erroneously Reinstalled Relay on Bus Tie Breaker CT-BT112
05000220/LER-1975-033, :on 751121,source Range Monitor 13 Failed to Provide Adequate Signal to Monitor.Caused by Failed Capacitor in Preamplifier Unit
05000220/LER-1975-030, :on 751001,main Steam Line Temp Switch Found to Actuate High.Caused by Setpoint Drift.Instrument Recalibr
05000220/LER-1976-017-01, :on 760428,fish Impingement on Traveling Screens Found in Excess of ETS Limits of 20,000 Per 24 H.Caused by Annual Migration
05000250/LER-1976-003-03, /03L:on 760519,output 1 of Pressurizer Level Comparator LC-459A Tripped at 4.685 Volts Instead of 4.680 Volts.Caused by Setpoint Drift.Trip Setpoint Reset to Conservative Value
05000220/LER-1975-024, :on 750911,average Power Range Monitor 14 Went Downscale.Caused by Loose Component in Power Supply.Problem Corrected
05000220/LER-1976-017, :on 760428,fish Impingement Upon Traveling Screens Found in Excess of ETS Limits of 20,000 Per 24 H.Caused by Annual Migration
05000285/LER-1976-005-03, /03L:on 760315,channel 383 Left Pressure Switch A/LC-383-1 Found Drifted Out of Spec.Cause Not Stated. Switch Recalibr & Will Be Checked Monthly for Proper Operation
05000285/LER-1976-021-03, /03L:on 760629,timer Relays for SI-3A,AC-3B & Si-3B Failed to Time Out at Set Times.Caused by Mechanical Binding of Time Relay Model HA-41A6-L-08.Timer Relays Tested Twice Weekly Until Replacements Received
05000285/LER-1976-025-03, /03L:on 760815,4,160 Volt Breaker T1B-3B Tripped on Instantaneous Overcurrent Relaying,Deenergizing 4,160/480 Volt Transformer T1B-3B & 480 Volt Bus 1B3B.Caused by Internally Faulted Transformer
05000285/LER-1976-030-01, /01T:on 760901,discovered High Alarm Setpoint on Steam Generator Blowdown Monitors RM-054A & RM-054B Set at 600,000 Counts Per Minute.Caused by Use of Unofficial Copy of Process Monitor Setpoints
05000285/LER-1976-006-03, /03L:on 760326,channel B Axial Power Distribution Positive & Negative Limits Read 12.1 & -5.4.Caused by adder-subtractor Module 19-301A Going Into Oscillation & Saturated.Module Replaced
05000285/LER-1976-026-03, /03L:on 760815,dc Bus 2 Ground Alarm Annunciated in Control Room & Smoke Observed Coming from Diesel Generator 2 Governor Motor Encl.Caused by RPM Governor Motor Armature Internally Faulted
05000280/LER-1976-013-03, /03L:on 760916,normal Boric Acid Makeup to Vol Control Tank Could Not Be Accomplished Due to Plugging of CVCS Line 1 inch-CH-56-152.Caused by Routine Use of Line. Blank Flange Installed to Clear Lines
05000281/LER-1976-015-03, /03L:on 761006,leakage of Water Observed from Recirculation Spray HX a Piping.Caused by Cloride Stress Corrosion of Type 304 Stainless Steel Piping.Repairs Will Be Made Following Investigation
05000281/LER-1975-015-01, /01T:on 750807,boron Injection Tank Recirculation Valves TV-2884 A,B & C Found Closed.Caused by Air Supply Valve 2-IA-451 Partially Throttled Due to Vibration
05000281/LER-1976-009-99, /99T:on 760204,main Steam Line Trip Valve TV-MS-201A Failed to Closed When Operated from Control Room. Caused by Valve Disc Binding Against Valve Body.Disc Opening Adjusted
05000281/LER-1976-002-01, /01T:on 760511,small Cracks & Radial Growth Observed on Periphery of Seventh Tube Support Plate.Caused by Change from Phosphate to Avt Chemistry.Further Investigation in Progress
05000281/LER-1976-001-03, /03L:on 760217,channel III Overtemp Setpoint Drifted 9% in Nonconservative Direction.Caused by Outputs of Summator TM-2-432 High Even Though Inputs Were Correct. Summator Replaced
05000281/LER-1976-003-03, /03L:on 760412,condenser Outlet Valve MOV-CW-200A Would Not Operate.Caused by Water in Limit Switch Compartment & Motor.Motor & Limit Switch Repaired & Limit Switch Compartment water-proofed
05000281/LER-1976-008-03, /03L:on 760614,condenser Outlet Valve MOV-CW-200B Would Not Operate Electrically.Caused by Broken Off Valve Operator Worm Shaft Tripper Cam.Tripper Cam Replaced & Valve Tested & Returned to Svc
05000280/LER-1976-005-01, /01T:on 760805,NSSS Vendor Informed of Error Discovered in LOCA ECCS Analysis.Reactor Vessel Upper Head Water Temp Should Be Assigned Value Similiar to Hot Leg Temp
05000280/LER-1977-008-03, /03L:on 770220,when Recirculation Halted to Replace Leaking Diaphragm in Valves 1-CH-98,150 Mwe/H Rampdown Initiated.Draphragm Failure Caused by Valve Overtightening When Shutting
05000281/LER-1976-005-03, /03L:on 760427,overall Integrated Containment Leakage Rate Found Greater than Acceptable Criterion.Cause Under Investigation.Repairs Will Be Made Per Investigation Results
05000280/LER-1976-004-03, /03L:on 760416,during Start Test,Emergency Diesel Generator 1 Damaged Due to Flooded Piston Cylinder 17. Caused by Crack in Cylinder Head.Engine Repaired
05000280/LER-1977-009-03, /03L:on 770219,chemical Addition Tank Discharge Valve MOV-CS-102A Position Indicating Lights Extinguished. Caused by Incorrectly Wired Switch.Maint Procedure Revised
05000281/LER-1976-009-03, /03L:on 760615,valve Operator MOV-2862B Would Not Operate When Cycled by Console Control Switch.Caused by Actuation of Thermal Overloads in Breaker housing.Three- Point Adjustment Screws Loosened
05000280/LER-1975-010-01, /01T:on 750412,valve FCV-GW-260 Failed to Shut as Required by Tech Specs.Caused by Westinghouse Model MG-6 Relay in Control Circuit for Valve Found Stuck in Operate Position.Relay Cleaned & Adjusted
05000317/LER-1983-077-04, /04T-0:on 831231,oyster Samples Collected During Dec 1983 from Camp Canoy Indicated Ag-110 Above ETS Limits. Caused by Natural Tendency of Oysters to Bioconcentrate Environ Silver
05000278/LER-1976-005-01, /01T:on 760111,three Snubbers on Lines RV-71A, RV-71K & RV-71H Inoperable Due to Empty Reservoirs.Caused by Leaking fittings,O-rings & Gaskets.All Defective Parts Will Be Replaced
05000278/LER-1976-053-01, /01T:on 760712,main Steam Relief Valve 71B Failed Open Causing Unit to Be Shut Down.Caused by Pilot Valve Seat Leakage.Relief Valve Replaced
05000277/LER-1977-005-01, /1P:on 770114,high Pressure Svc Water,Emergency Svc Water & Emergency Cooling Water Pumps Did Not Meet FSAR Seismic Requirements.Caused by Change in Calculation Techniques.Higher Strength Bolts & Restraints Added
05000277/LER-1976-074-03, /03L:on 761101,control Room Radiation Sampling Sys Low Flow Alarm & Low Flow Isolation Signal Not Received from Flow Switches FS-0760 a & B.Caused by Wiring Error.Wiring Error Corrected,Alarm Tested Successfully & Test Rewri
05000277/LER-1976-037-03, /03L:on 760426,reactor Level Switch LIS 2-2-3-101B Observed to Bounce When Trip Signal Applied.Caused by Defective Microswitch in Barton Model 288A Level Indicating Switch.Microswitch Replaced,Recalibr & Tested
05000277/LER-1976-019-03, /03L:from 760315 to 760328,RHR HX 2A Leak Permitted Radioactive Water to Leak from Condensate Storage Transfer Sys to River.Caused by Two Leaking Tubes & Failed Internal Bellows
05000277/LER-1976-075-03, /03L:on 761109,core Spray a Full Flow Test Return Valve MO-26A Failed to Close.Caused by Motor Operator Gear Train Failure.Valve Operator Replaced & Valve Operated Properly
05000277/LER-1976-015-01, /01T:on 760304,gaseous Release Rate Exceeded Tech Spec Limit.Caused by Backwash Delay.Mod Currently Under Investigation Would Direct Backwash Venting to Hotwell, Allowing Gaseous Effluent Benefit of Offgas Sys
05000277/LER-1976-054-01, /01T:on 760719,HPCI Turbine Speed Could Not Be Controlled by Controller or Test Pot.Caused by Two Defective 2166 Zener Diodes & Defective 747 Integrated Circuit Chip in Ramp Generator & Signal Converter Assembly
05000277/LER-1976-033-01, /01T:on 760428,hydraulic Snubber SS-2-B on Recirculation Pump Sys Found Inoperable Due to Empty Reservoir.Caused by Defective Seals & O Rings.Defective Parts Will Be Replaced & Snubbers Tested
05000277/LER-1976-039-03, /03L:on 760507,required Source Range Monitor Surveillance Test Not Done Due to LPRM String Replacement. Importance of Test Completion Emphasized to Personnel
05000277/LER-1976-058-01, /01T:on 760820,torus Vol Fell Below Tech Spec Level.Caused by Defective Positioner on Control Valve Returning Condensate to Torus.Valve Positioner Repaired & Valve Returned to Svc
05000277/LER-1976-046-01, /01T:on 760629,all Four Recombiner Hydrogen Analyzers Found Valved Out of Svc.Caused by Procedural Deficiency.Plant Procedures Revised
05000277/LER-1976-031-01, /01T:on 760428,11 Hydraulic Snubbers on Main Steam Relief Valve Discharge Lines Found Inoperable.Ten Inoperable Because of Empty Reservoirs & One Because of Rotated Reservoir.Caused by Defective Seals & O Rings
05000277/LER-1976-024-03, /03L:on 760408,control Room Radiation Monitor RIS-0760A Failed in Low Count Direction.Caused by Logic Chip Vibrating Out of Socket.Logic Chip Reinserted & Unit Operated Properly
05000277/LER-1976-062-01, /01T:on 760825,suppressor on Main Steam Relief Valve Discharge Line C Found W/Empty Reservoir.No Apparent Cause Found.Suppressor Refilled & Leak Checked Prior to Reinstallation
05000277/LER-1976-081-03, /03L:on 761228,RCIC Steam Supply Isolation Valve MO-13-16 Failed to Respond to Auto Open Signal During Routine Surveillance Testing.Caused by Valve Motor Damage Due to Failure of Torque Switch.Motor & Switch Replaced
05000277/LER-1976-071-03, /03L:on 761005,RCIC Trip Throttle Valve Would Not Reset After Trip.Caused by Grounded Wire on Trombetta Trip Solenoid Model G-206.Solenoid Repaired
05000277/LER-1976-056-03, /03L:on 760803,control Room Ventilation Radiation Monitor RIS-0160A Displayed Abnormal Reading.Caused by Failure of Integrating Circuit in Exponent Counting Circuit of Trapelo DRM-100 Digital Process Radiation Monitor
05000277/LER-1976-053-03, /03L:on 760712,second Quarter Average Release Rate for Iodine & Particulate Exceeded Tech Spec.Caused by Shutdown & Depressurization for Refueling
05000277/LER-1977-001-01, /01T:on 770104,reservoirs of Hydraulic Snubber Relief Valves RV-71E & SS-C6 Found Empty.Caused by Reservoir Leak & Loose Locking Nut Allowing Unit to Turn Upside Down. Repairs Made & Reservoirs Filled
05000277/LER-1976-027-03, /03L:on 760409,relief Valve Bellows Leak Detector Switch PS-2-2-71L Failed to Trip as Result of Broken Wire Connector to Switch.Connector Replaced
05000261/LER-1977-006, :on 770326,during 0% Power,Valve V2-14A Failed to Open While Attempting to Feed Steam Generator a Through Valve W/Steam Driven Auxiliary Feedwater Pump.Caused by Binding Valve Seat Surfaces.Valve Recycled
05000277/LER-1976-064-03, /03L:on 760829,containment Atmosphere Dilution Sys Declared Inoperable Because Liquid Nitrogen Tank Relief Valve Failed to Reseat,Blowing Down Content Below Limits. Blowback Ring Replaced
05000277/LER-1976-040-03, /03L:on 760509,gamma Scan Not Performed Prior to Two Liquid Effluent Releases.Caused by Lack of Radwaste Storage Capacity.Beta Activity Reviewed Prior to Release. Based on Previous Data,Limit Would Not Be Exceeded
05000277/LER-1976-060-03, /03L:on 760821,improper Sample Obtained from Drywell Radioactive Gas Sampling Sys Due to Leakage.Caused by Loose Fitting on Electrical Penetration.Fitting Tightened
05000277/LER-1976-036-01, /01T:on 760428,three Hydraulic Snubbers on Feedwater Sys Found Inoperable.Two Snubbers Failed Because of Rotated Reservoir.Snubbers Repaired or Will Be Repaired
05000277/LER-1976-018-01, /01T:on 760329,gaseous Release Rate Exceeded Rate Allowable.Caused by Depressurization of Reactor to Main Condenser.Release Rate Returned to Normal,Vacuum Established & Depressurization Restarted
05000278/LER-1976-003-03, /03L:on 760106,main Steam Line Radiation Monitor RIS-251A Did Not Trip at Desired High Trip Setpoint.Caused by Setpoint Drift.Setpoint Adjusted to Acceptable Value
05000277/LER-1977-006-03, /03L:on 770111,transient in-core Machine Probe Travelled Beyond in-shield Limit Switch During Withdrawal. Caused by Personnel Misoperation & Short Circuit in Backup Circuit.Short Corrected
05000277/LER-1976-077-01, /01T:on 761114,main Steam Relief Valve 71F Failed Open.Caused by Dirt Under Pilot Disk & Seat,Leading to Seat Leakage & Cutting,Precipitating Valve Lifting.Plant Shut Down & Relief Valve Replaced
05000277/LER-1976-078-03, /03L:on 761115,PS-2-2-134B & PS-2-2-134A Tripped at 845 Psig & 860 Psig,Respectively.Caused by Setpoint Shift.Switches Recalibr
05000277/LER-1976-080-03, /03L:on 761118,outboard MSIV Failed to Close During Surveillance Testing Due to Backseat Deformation. Caused by Valve Stem Gauging & Preventing Free Valve Movement.Valve Repaired & Tested Satisfactorily
05000277/LER-1977-003-01, /01T:on 770103,insp of Four Relief Valves Revealed Delamination & Overheating of Air Operator Diaphragms.Cause Not Stated.Diaphragms Replaced
05000277/LER-1976-052-03, /03L:on 760710,probe 1 Stopped 1 Inch Before Reaching Preset Shield Limit During Withdrawal & Machine Ball Valve Did Not Close.Probe Machine Shield Limit Switch Operated Spuriously Causing Incomplete Withdrawal
05000271/LER-1975-007, :on 750309,personnel Observed Flow Fault Alarm & Loss of Power Indication on Containment Air Sampling Sys Sample Pump.Caused by Bearing Seizure.Pump Replaced
05000277/LER-1976-084-03, /03L:on 761217,HPCI Steam Line High Flow Switch DPIS-2-23-76 Found Higher than Tech Spec Limit.Caused by Setpoint Shift.Switch Recalibr & Tested Satisfactorily
05000277/LER-1976-023-03, /03L:on 760405,drywell High Pressure Switches PS-2-10-101C & PS-2-10-119C Found Valved Out of Svc.Caused by Personnel Error.Verification of Valve Lineup After Tests Emphasized
05000277/LER-1976-061-03, /03L:on 760823,drywell Radioactive Gas Sample Pumps Tripped & Sample Sys Isolated,Removing Sys from Svc. Relay GE CR120AD04041AA Failed in Fail Safe Position.Relay Replaced & Sys Returned to Svc
05000263/LER-1976-003, :on 760504,during Test,Primary Containment Oxygen Concentration Found Above Tech Spec Limit.Caused by Leaking Asco Solenoid Valve.Solenoid Valve Isolated
05000278/LER-1976-069-03, /03L:on 761011,core Flow Bias Input to a Logic APRM String Found 4% High.Caused by Absence of Offset Signal in GE Flow Bias Proportional Amplifier.Amplifier Removed from Svc & Signal Normalized.Failure Not Duplicable
05000263/LER-1976-023-01, :on 760924,surveillance Coordinator Failed to Locate Main Steam Line Radiation Monitor Functional Test Scheduled for Wk of 760912.Caused by Test Overlooked & Not Assigned for Completion
05000277/LER-1976-072-03, /03L:on 761005,setpoint of Automatic Depressurization Sys Confirmatory Low Level Switch LIS 2-2-2-83A Was 0.85 Inches Lower than 6-inch Tech Spec Limit.Caused by Slight Setpoint Drift.Switch Recalibr
05000263/LER-1977-001, :on 770118,during Normal Operation,Accumulator on Control Rod Drive Hydraulic Control Unit 14-19 Declared Inoperable.Caused by Failure to Hold Pressure Due to Leaking Stem Packing.Packing Replaced
05000263/LER-1976-006, :on 760603,during Test,Hpci Steam Line Inboard Isolation Valve Failed to Close Completely.Caused by Torque Switch Setting Drifting Too Low.Switch Reset
05000278/LER-1976-007-01, /01T:on 760111,hydraulic Snubber on a Reactor Recirculation Pump a Inoperable Because of Empty Reservoir. Caused by Leaking fittings,O-rings & Gaskets.Defective Parts Replaced
05000362/LER-1983-108-03, /03L-0:on 831125,qualified Safety Parameter Display Sys (QSPDS) Channel a Failed & Declared Inoperable. Caused by Interference in Plasma Display Unit Due to Ground Loops.Grounding Configuration Modified
05000271/LER-1976-023-01, /1T:on 760724,false All Rods in Signal Received for Rod Manual Control Sys.Caused by Position Indicating Switch on Rod 34-07 Stuck in Closed Position Due to Failed Probe Buffer Card.Card Replaced & Tested
05000267/LER-1976-032, :on 761030,steam Outlet Block Valve Fuse Would Not Shut After Circulation Transferred to Water Drive.Caused by Stuck Solenoid Valves on Hydraulic Sys.Solenoids Changed on Eight Valves
05000271/LER-1976-030-03, /3L:on 760826,GE Model 8HG1A02011 Drywell Atmospheric Temp Recorder TR-1-149 Failed.Caused by Broken Hub on Chart Drive Mechanism.Mechanism Rebuilt & Recorder Returned to Svc
05000271/LER-1976-036-03, /3L:on 760930,UPS-1A Trouble Alarm Received.Caused by Filter Capacitor Bank Fuse Clearing Due to Shorted GE Model 86F1323J Capacitor.Bank Will Be Repaired.Investigation Underway by Manufacturer
05000271/LER-1976-025-03, /3L:on 760813,Exide 250 Kva Uninterruptible Power Supply Output Breaker Tripped,Resulting in Loss of Voltage to Motor Control Ctr 89B.Trip Caused by Noise Entering Unused Static Switch Open Sensing Circuit
05000317/LER-1983-056-03, /03L-0:on 831007,heat Damaged Snubber Discovered on Piping Between Pressurizer & Code Safety Valve.Caused by Lack of Oil in Reservoir on Snubber.Modified Reservoir Design Implemented.Update Expected
05000387/LER-1983-108-03, /03L-0:on 830726,operations Personnel Received Drywell Floor Drain Sump High Level Alarm.Caused by Crossed Wires.Wires Restored to Proper Postions
05000260/LER-1950-260-763, /763W:on 760412,five Reed Relays Failed.Four Reed Relays Permit Sequential Selection & Withdrawal of Control Rods & One Permits Two Control Rod Simultaneous Withdrawal. Caused by CP Claire Reed Relay Contact Failure
05000265/LER-1976-005-03, /03L-0:on 760519,during Monthly MSIV Surveillance Test,Failed to Receive Channel a RPS Trip.Caused by Improper Valve Closure Test Circuit Reset.Test Switch Held Longer
05000265/LER-1976-006-03, /03L-0:on 760427,during Routine Monthly Surveillance on Ps 2-1469,ECCS Fill Sys Discharge Header Pressure Switch Found to Trip Beyond Tech Spec Limit.Caused by Instrument Drift.Pressure Switch Reset
05000265/LER-1976-003-03, /03L-0:on 760319,outboard MSIV AO-2-203-2C Failed to Close & Inboard Gave Open & Closed Indications.Caused by Foreign Matl in Pilot Assembly.Double Indication Cleared
05000265/LER-1976-012-01, /01T-0:on 760825,pressure Switch Ps 2-1001-90B Found Valved Out.Caused by Switch Being Left Isolated After Completion of Prior Month Surveilance testing.W/760924 Forwarding Ltr
05000265/LER-1976-007-03, /03L-0:on 760527,while Performing Main Steamline High Flow Functional Test,Differential Pressure Indicating Switch 2-261-2S Tripped Beyond Tech Spec Limit.No Cause Stated.Switch Recalibr
05000254/LER-1976-017-03, L-0:on 760427,while Performing MSIV Surveillance, Duel Indication Received for Valves AO 1-203-1B & AO 1-203-1D.Caused by Switches Being Out of Alignment.Minor Air Leak repaired.W/760430 Forwarding Ltr
05000265/LER-1976-009-01, /01L-01:on 760627,during Surveillance Test,Dual Indication for Drywell/Torus Vacuum Breaker AO 2-1601-33A Received.Caused by Failed Micro Switch Type BAG1-2RN Limit switch.W760726 Forwarding Ltr
05000265/LER-1976-017-03, LER 017/03L-0:on 761203,Grinnell Corp Snubber 4755 on RCIC Steam Supply Piping Found to Have Empty Oil Reservoir. Caused by Leakage Through Reservoir End Gap Gaskets.Snubber Repaired & Reservoir Refilled w/oil.W/761230 Forwa
05000254/LER-1976-015-03, /03L-0:on 760325,standby Liquid Control Sys Pump B Had Discharge Pressure Fluctuations & Excessive Pump Noise.Caused by Setpoint Drift of Relief Valve B & Leaking of Internal Check valves.W/760423 Forwarding Ltr
05000265/LER-1976-011-03, /03L-01:on 760717,four Drywell Pressure Switches Rendered Inoperable.Caused by Blocked Sensing Line.Line Blown Clear W/Instrument air.W/760820 Forwarding Ltr
05000254/LER-1976-020-03, /03L-0:on 760701,loss of Indication & Operability Occurred on Containment Spray Loop B Outboard Valve MO-1-1101-23B.Caused by Loose hold-down Bolts.Bolts tightened.W/760729 Forwarding Ltr
05000000/LER-1976-018-03, /03L-0:on 760522,snubber 4439 RHR Sys to Fuel Pool Sys Cross Tie Line Found to Have Empty Oil Reservoir Due to Leaking Reservoir Shaft Seal.Caused by Equipment Failure.Snubber Internals replaced.W/760621 Forwarding Ltr
05000254/LER-1976-013-03, /03L-0:on 760317,diesel Generator 1/2 Out of Svc Too Long for Preventive Maint.Caused by Commuication Problem Between Operating & Maint Depts.Precaution to Be Added to Station procedure.W/760415 Forwarding Ltr
05000265/LER-1976-010-03, /03L-0:on 760712,suppression Chamber Purge Valve AO 2-1601-56 Failed to Close During Surveillance Testing. Caused by Stuck Solenoid Valve SO 2-1601-65.Solenoid cleaned.W/760810 Forwarding Ltr
05000265/LER-1976-015-03, /03L:on 761012,five RCIC Turbine Area High Temp Switches Tripped at Temps Exceeding 200 F.Caused by Instrument Setpoint Drift.Switches recalibr.W/761110 Forwarding Ltr
05000247/LER-1950-247-01, /01L:on 750829,during Normal Operation,Two Charging Pumps Became Inoperable.Caused by Excessive Seal Leakage.Design Mods investigated.W/750926 Forwarding Ltr
05000220/LER-1976-036, :on 761015,lo-lo-lo Reactor Water Level Switch RE-18A Failed to Provide Trip at Indicated Inches.Caused by Apparent Setpoint Drift.Switch Inspected & Recalibr.W/
05000244/LER-1975-008-01, /01T:on 750408,post-accident Filter Charcoal Samples Showed Filter a Efficiency of 99.4% While B Above Criteria of 99.9%.Caused by Charcoal Aging.Tech Spec Change Considered to Replace Criteria of 99.9%
05000220/LER-1983-036-03, /03L-0:on 831107,fuel Zone Water Level Monitoring Accurex Sys Found in Idle State.Cause Unknown Suspected That Stop Signal Received Stopping Program.Accurex Logger Restarted & Addl Surveillance Performed
05000260/LER-1983-062-03, /03L-0:on 831004,while Performing Surveillance Instruction 4.9.A.1(a),second Starter on Diesel Generator C Engaged W/Diesel While Operating at 900 Rpm.Caused by Air Leak in Solenoid Valve.New Valve Installed
05000361/LER-1983-094-03, /03L-0:on 830217,Unit 2 Fire Detector Electrical Panel 2L-204 Failed Surveillance Test & on 830222,Unit 3 Panel 3L-204 Failed Same Test.Caused by Disconnected Supervisory Circuits as Result of Mods
05000362/LER-1983-070-03, /03L-0:on 830923,control Element Assembly Calculator 1 Declared Inoperable When Control Element Assembly 15 Indicated Spurious Rod Movement.Caused by Failed Circuit Board
05000361/LER-1983-153-13, /13X-0:on 831204,during Surveillance Testing, Undervoltage Trip Devices of Reactor Trip Breakers 1 & 4 Exhibited Scattered & Unacceptable Response Times.Reactor Trip Breakers Replaced
05000361/LER-1983-124-03, /03L-0:on 830917 & 23,control Element Assembly Calculator Declared Inoperable Due to Spurious Position from Control Element Assembly 20.Caused by Defective Board & Connector.Equipment Replaced
05000361/LER-1983-123-03, /03L-0:on 830913,w/Unit 2 in Mode 1 & Unit 3 in Mode 3,insp of Electrical Penetrations Revealed Two Holes in Penetration Seals in Auxiliary Bldg Control Area.Caused by Procedural Deficiencies During Const
05000361/LER-1983-119-03, /03L-0:on 830828,Group 6 Control Element Assemblies (CEA) Inserted to Control Axial Shape Index. Reactor Coolant Cold Leg Temp Observed Below Limits.Caused by Effects of Xenon build-in & CEA Insertion
05000387/LER-1983-125-03, /03L-0:on 830903,average Drywell Air Temp Exceeded Tech Specs by 1 Degree.Cause Not Stated.Plant Startup & Heatup Procedures Revised
05000361/LER-1983-104-03, /03L-0:on 830809,during Routine Visual Insp,Purge/ Vent Stack Monitor 2RI-7865 Discovered W/Low Flow.Caused by Apparent Unauthorized Valve Manipulation.Valve Opened & Proper Flow Restored
05000270/LER-1983-009-01, /01T-0:on 830822,discovered That,Using Conservative Interpretations,Inoperable LPI Snubber Noted. Snubber Not Made Operable within 72 H.Caused by Component Failure & Personnel Error.Snubber Replaced
05000260/LER-1983-049-03, /03L-0:on 830725,while Performing Surveillance Instruction 4.2.B-60,core Spray Ne Room Cooler Fan Would Not Operate.Caused by Tripped Overload Relays in Full Voltage Nonreversing Magnetic Starter.Relays Replaced
05000317/LER-1983-072-01, /01T-0:on 831222,reactor Protection Sys Channels a & C for Reactor Coolant Flow Inoperable.Caused by Erratic Indication & Procedure Inadequacy.Transmitter Repaired & New Flow Setpoint Inserted
05000387/LER-1983-052-03, /03L-0:on 830325,during Surveillance Test,Creoass Train a Tripped.Caused by Fan Belts Coming Off Fan Pulley. Belts Replaced & Bearings & Fan Pulley Realigned
05000302/LER-1983-063-01, /01T-0:on 831226,while Performing Routine Surveillance,Level Indicators FS-1-LI & FS-2-LI & Sensing Lines for Fire Svc Tanks Found Frozen.Caused by Unusually Cold Weather.Water Added to Tanks
05000387/LER-1983-123-03, /03L-0:on 830901,reactor Bldg Zone III Ventilation Tripped,Causing short-duration Loss of 0.25 Inches.Caused by Momentary,Spurious Signal.Investigation Revealed Absence of Zone III Isolation Signal
05000387/LER-1983-127-03, /03L-0:on 830909,during Surveillance of Standby Liquid Control Sys,Available Weight of Sodium Pentaborate (5,250 Lbs) Discovered Below Limit of 5,500 Lbs.Caused by Sys Configuration at Odds W/Procedure
05000361/LER-1983-070-03, /03L-0:on 830613,while in Mode 1,two Steam Leaks Observed in Line to turbine-driven Auxiliary Feedwater Pump 2P-140.Caused by Leaking Plug on Turbine Stop Valve & Valve Seating Surfaces.Plug Replaced
05000387/LER-1983-036-03, Fuse Supplying Topaz Inverter Blew Several Times,Affecting Operation of RCIC Instrumentation & Speed Control Circuitry at Remote Shutdown Panel.Cause Unknown.Recorders Installed
05000362/LER-1983-051-03, /03L-0:on 830712,while in Mode 4,condenser Air Ejector Monitor 3RT-7870 Discovered to Have Low Flow During Routine Daily Surveillance & Declared Inoperable.Caused by Valve Manipulation by Unauthorized Personnel
05000324/LER-1983-026-03, /03L-0:on 830313,suppression Pool Level Indicator/ Recorder 2-CAC-LR-2602 Showed out-of-spec Low Level While Redundant Level Indicators Showed Normal Level.Caused by out-of-calibr Instrument Transmitter.Device Recalibr
05000387/LER-1983-027-03, /03L-0:on 830219,technician Discovered That PSH-B21-N056 B & C (Low Condenser Vacuum Pressure switches-channel B & C) Did Not Meet Tech Spec.Caused by Setpoint Drift.Switches Recalibr
05000348/LER-1983-021-03, /03L-0:on 830506,power Supply Breaker HBL7R Opened.Possibly Caused by Personnel Inadvertently Tripping Breaker by Closing Locker.Locker Moved
05000269/LER-1983-003-03, /03L-0:on 830120,engineering Safeguards Channels A,B & C Reactor Bldg narrow-range Pressure Transmitter Drifted Out of Calibr.Caused by Deficient Procedures. Channels Recalibr & Procedures Changed
05000267/LER-1978-031-03, /03L-0 on 780925:during Routine testing,1 of 5 Heating Ventilation & Air Conditioning Sys Isolation Dampers for 480 Volt Switchgear Room Would Not Shut,Due to Faulty O-ring in Damper Jamming Open Actuating Shaft
05000387/LER-1982-041-03, /03L-0:on 821013,turbine Bldg Special Particulate Iodine Noble Gas Monitor Taken Out of Svc.Alternate Sampling Commenced While Monitor Out of Svc.Sampling Discontinued Since Sping Operating During Sampling.No Caused Stated
05000395/LER-1982-026-03, /03L-0:on 821019,operator Noticed Frequent Auto Reactor Coolant Makeup to Vol Control Tank of Chemical Vol & Control Sys.Caused by Cracked Safety Injection Filter B Vent Valve.Leak Test Performed W/Results of 12 Gpm
05000416/LER-1983-035-01, /01T-0:on 830209,performance of Previous Refueling Interlock Surveillance Procedure Found to Violate Tech Specs Since Reactor Mode Switch Placed in Startup/Hot Standby Position.Cause Not Stated.Procedure Changed
05000219/LER-1978-022-03, /03L-0 on 781017:during Routine Surveillance Test of Standby Gas Treatment Sys,The Sys II Discharge Valve Failed to Open,Due to Stuck Solenoid in Control Air Supply to Operator for V-28-30
05000387/LER-1982-070-03, /03L-0:on 821208,while Reviewing Past Completed Surveillances for Determining Component Operability, Operational Condition 2 Entered Prior to Required Surveillances.Caused by Lack of Trigger Mechanism
05000387/LER-1983-012-03, /03L-0:on 830113,during Startup Test Program, Reactor Recirculation Pump a Tripped Off.Caused by Defective Transformer That Had Shorted Secondary.Transformer Replaced. Pump Returned to Svc
05000263/LER-1977-027, :on 770923,RHR Torus Cooling Valve Body Seat Ring Threads Found to Be Stripped.Caused by Rotation of Plug Which Unscrewed Seat.Mod in Process to Hold Seat in Place Using Bolding Ring Welded to Valve Body
05000155/LER-1982-014-03, /03L-0:on 820422,chemical Waste Tank Recycle Line Leak Discovered.Spillage Contained in Radwaste Collection Sys.Caused by long-term Corrosion & Excessive Acid Use During 820422 Makeup Regeneration
05000263/LER-1982-004-01, /01T-0:on 820410,ASCO Inboard & Outboard Drywell Vent 3-way Solenoid Valves,Model 830064C64U,failed to Close Upon Hand Switch Activation When Coil de-energized.Probably Caused by Horizontally Mounted Solenoids.Valves Replace
05000270/LER-1982-002-01, /01T-0:on 820122,three Core Support Assembly Thermal Shield Bolts Found W/Heads Broken Off & Shock Pad Y-2 Attachment Bolts Discovered Broken.Caused by Intergranular Stress Corrosion Cracking.Pad Removed
05000369/LER-1981-194-03, /03L-0:on 811230,during Periodic Fire Pump Operability Test,Discovered That Fire Pump C Would Not Start.Cause Undetermined.Update Rept Will Be Submitted by 820226
05000369/LER-1982-001-01, /01T-0:on 820106,routine Review of Source Document Changes Revealed Class H Piping in Fire Protection Sys in Diesel Generator Room 1A Routed Above One Nuclear safety-related Essential Cable & Instrument Panel
05000269/LER-1981-020-03, /03L-0:on 811029,hydrogen Purge Unit Declared Inoperable Due to Substandard Heat Output from Dehumidifier Heaters.Caused by Frayed Conductor Cable Due to Suspected Thermal Embrittlement & Mechanical Vibration
05000247/LER-1981-025-99, /99X-0:on 811009,code Safety Valve Ms 48A on Main Steam Line 21 Was Found Lifting at Lower than Specified Pressure.Caused by Broken Section on Disc Holder in Valve. Defective Parts Replaced
05000295/LER-1981-046-03, /03L-0:on 811023,U1 Offgas Particle & Gas Radiation Monitors Not Pulling Representative Sample & Release Path Not Being Continuously Monitored.Caused by Air in-leakage Due to Worn O-rings on Detector Housing Assembly
05000263/LER-1981-021-01, /01T-0:on 811024,during Cold Shutdown Primary Containment Isolation Sys Logic Relay Coil Failed & Relay Did Not Immediately Trip.Caused by Natural end-of-life. Replaced Relay
05000369/LER-1981-118-01, /01T-0:on 810731,analysis of RCS Flow Coastdown Test Data Showed Test Failed Some Acceptance Criteria. Apparently Caused by Westinghouse Computer Predicted Curves Being More Optimistic than Actual Sys Characteristics
05000369/LER-1981-111-03, /03L-0:on 810706,during Maint,Main Feedwater Containment Isolation Valve Was Found Open.Probably Caused by Open Line Pressure Driving Valve.Valve Closed & Locking Device Installed
05000348/LER-1983-001-03, /03L-0:on 830102,RCS Subcooling Monitor Channel 2 Declared Inoperable Following Receipt of Main Control Board Alarms.Caused by Faulty Printed Circuit Card.Connector Pins on Card Cleaned
05000348/LER-1983-042-03, /03L-0:on 830802,post-LOCA Hydrogen Recombiner 1A Declared Inoperable.Caused by Failure of Temp Indicator.New Indicator Installed & Declared Operable
05000369/LER-1983-050-03, /03L-0:on 830629,control Area Ventilation Sys Train B Declared Inoperable.Caused by Automatic Reset Preheater Overtemp Cutout Switch Failure.Replacement Switch Will Be Installed
05000387/LER-1983-086-03, /03L-0:on 830525,reactor Bldg Door Opened While Maint Performed on Turbine Bldg Side of Air Lock to Reactor Bldg.Caused by Personnel Error.Individual W/Radio Communication Will Be Posted
05000387/LER-1983-063-03, /03L-0:on 830411,main Steam Line Drain Valve Leakage Exceeded Tech Spec Limit.Cause Not Stated.Seal Ring Replaced,Outboard Valve Lapped & Valves Reassembled
05000348/LER-1983-012-03, /03L-0:on 830402,overtemp-delta Temp Loop 2 Channel II Declared Inoperable When Bistables 422C1-2 Tripped.Caused by Power Supply Failure of Comparator Card. Card Replaced & Loop Calibr
05000369/LER-1981-130-03, /03L-0:on 810805,ionization Smoke Detector in Fire Zone 72 Failed Channel Functional Test.Caused by Deterioration of Integral Printed Circuitry Due to Boric Acid Deposits in Honeywell Detector,Type TC 100A
05000293/LER-1981-030-04, /04T-0:on 810603,lab Rept Indicated Concentration of Co-60 in Mussel Taken from Discharge Canal/Outfall on 810505.Caused by Improved Analytical Techniques,Detecting Sensitivities Below Capabilities Specified in Tech Specs
05000305/LER-1981-018-03, /03L-0:on 810516,testing Indicated That Low Pressure Safety Injection & Reactor Trip Were Below Tech Spec Limits for Pressure Transmitters.Caused by Instrument Drift.Sensing Lines Flushed.Amplifier Replaced
05000029/LER-1977-031-03, /03L-0:on 770609,loop Seal Radiation Monitor Pegged at Low End of Scale.Caused by RM-40 Power Supply High Voltage Tripping.Voltage Adjusted
05000029/LER-1976-011-03, /03L-0:on 760907,slight Leakage Noted from Welded Nipple on Charging Pump 3 Discharge Heater Line.Caused by Failure to Allow 1/16-inch Pull Back Gap During Installation of Weld.Pump Isolated & Nipple Replaced
05000318/LER-1980-056-03, /03L-0:on 801116,control Element Assembly 1 Dropped Into Core.Cause Undetermined.Power Reduced to Less than 70% & Control Element Assembly Returned to Group Height
05000029/LER-1977-032-03, /03L-0:on 770611,during Surveillance testing,TV- 209 Containment Drain Line Trip Isolation Valve Failed to Close.Caused by Excessively Tightened Packing.Packing Probably Overtightened During Recent Containment Leak Insp
05000029/LER-1976-005-03, /03L-0:on 760520,auxiliary Operator Noted Slight Leakage from Weld on Inlet Charging Pump 3 Relief Valve. Caused by Pullback Gap Not Allowed During Installation of Pipe & Vibration Induced Fatigue Failure
05000029/LER-1976-008, Updated LER 76-008/010-0:on 760730,review of Rod Ejection Accident Analysis Revealed Error in Method Used for Core 11 Analysis.Caused by Error in Methods & Application of Analysis Codes.Sys of Documentation Control Initiated
05000029/LER-1977-011-03, /03L-0:on 770301,emergency Diesel Generator 1 Starter Motor Failed During Surveillance Test.Caused by Armmature Shaft Being Broke.Starting Motor Replaced
05000029/LER-1977-018-03, /03L-0:on 770326,steam Generator Chloride Concentration Increased to Max Level of 4 Ppm in Steam Generator 2,exceeding Tech Specs Limit
05000029/LER-1977-028-03, /03L-0:on 770530,noble Gas Monitor of Primary Vent Stack Radiation Detection Sys Failed.Cause Could Not Be Ascertained as Trouble Could Not Be Repeated After Alarm Reset
05000029/LER-1977-012-03, /03L-0:on 770306,alarm Setpoint Adjustment of Radiation Monitor for Steam Generator Blowdown Found Defective.Caused by Alarm Setpoint Control Failure to Adjust.Control Replaced
05000029/LER-1977-009-03, /03L-0:on 770221,primary Vent Stack Monitor Particulate Channel Alarmed Due to Blown Fuse.Caused by Ledex Stepping Motor Failing to Advance Filter Paper Which Overloaded Driving Transistor.New Motor & Fuse Installed
05000029/LER-1977-008-03, /03L-0:on 770204,iodine Channel of Primary Vent Stack Radiation Monitoring Failed to Meet Count Rate Acceptance Criteria.Caused by Mechanical Stops Being Misaligned W/Detector.Stops Aligned & Tightened
05000029/LER-1977-027-03, /03L-0:on 770524,biannual Recalibr Performed on Two LPIS Accumulator Channels.Instruments Below Tech Specs Limit.Recalibr Adjustments Made to Bring Channels within Tech Specs Limit
05000029/LER-1977-017-03, /03L-0:on 770324,following Plant Trip,Chlorides in Steam Generator 4 Exceeded Tech Specs Limits.Caused by Impurities Released in Bulk Water
05000029/LER-1977-021-03, /03L-0:on 770420,air Mass Calculation Performed on 770419 Indicated That Significant Leak in Primary Containment Might Exist.Data Point Indicated That VC Air Pressure Had Fallen.No Leak Found,Reactor Cooled Down
05000029/LER-1977-004-03, /03L-0:on 770114,charging Pump 2 Discharge Pressure Failed to Meet Tech Specs Surveillance Requirement. Caused by Requirements Based on Centrifugal Instead of Reciprocating Type Pump.Proposed Change Initiated
05000029/LER-1977-013-03, /03L-0:on 770307,following Power Reduction to Identify Plug Leaking Condenser Tube,Chlorides in Steam Generators 1 & 4 Exceeded Tech Specs Limits.Caused by Chloride Concentration Buildup in Steam Generator
05000029/LER-1977-022-03, /03L-0:on 770421,steam Generator Chloride Concentration Increased to Max Level of 0.8 Ppm in All Four Steam Generators,Exceeding Tech Specs Limits.Caused by Chloride Entering Steam Generator in Feedwater Areas
05000029/LER-1977-014-03, /03L-0:on 770308,iodine Channel of Primary Vent Stack Radiation Monitoring Sys Failed to Meet High Level Count Rate Acceptance Criteria.Caused by Voltage Drift. Voltage Adjusted
05000293/LER-1980-036-01, /01T-0:on 800806,found Hourly Fire Check of Auxiliary Offgas Bldg Not Performed on Continuous Basis Since 800707 While Fire Detection Units Were Inoperable. Caused by Communications Lapse Between Personnel
05000368/LER-1980-053-03, /03L-0:on 800721,CEAC 1 Failed During Mode 1 Operation.Cause Not Determined.Ceac Sys Software Reloaded, Periodic Tests Performed & Failure Indications Returned to Normal.Ceac Returned to Operable Status on All Channels
05000213/LER-1976-012-01, /01T-0:on 760617,during Refueling mode,1,600 AMP Frame Size Tie Breaker 6T7 Opened de-energizing Bus 6 & Allowing 1B RHR Pump to Lose Power.Caused by Inadequate Procedures Re 480 Volt Bus Tie Breaker Overload
05000213/LER-1976-004-04, /04L-1:on 760202,Jan 1976 Monthly Impingement Loss for Spottail Shiners Exceeded ETS Limits.No Corrective Action Taken
05000213/LER-1977-001-03, /03L-0:on 761214,small Leak Found at Juncture of Waste Liquid/Steam Generator Blowdown Line & Svc Water Effluent Line.Caused by Pipe Matl Deterioration from Steam Generator Blowdown Stream & Cold Svc Water Interaction
05000213/LER-1976-014, /01T-0:on 760626,power to Residual Heat Removal Pump Interrupted for 30-s.Caused by Automatic Circuit Breaker Trip on Station Svc Transformer Due to Spurious 115 Kv Fault Signal.Backup Sensing Circuits to Be Changed
05000213/LER-1976-019-03, /03L-0:on 761001,concentrated Boric Acid Pump 1A (Canned Motor) Developed Leak in Can.Caused by Wiped Pump Bearings Allowing Rotor to Drop & Wear Hole Through Can.Pump Replaced W/Spare & Rebuilt
05000213/LER-1976-003-03, /03L-0:on 760202,Channel 33 Overpower Trip Setpoint Exceeded Limit.Caused by Normal Instrument Drift. Setpoint Reset to Allow for Drift W/O Exceeding Limit
05000213/LER-1976-017-03, /03L-0:on 760720,loop 2 Steam Line Flow Indicator Failed Low,Annunciating on Main Control Board.Caused by Leaking Sensing Line cross-threaded Fitting on High Side of Loop 2 Pressure Transmitter.Damage Fitting Replaced
05000213/LER-1976-006-03, /03L-0:on 760203,emergency Diesel EG-2B Tripped on Overspeed.Caused by Calibr Tool Left in Injector Rack Following Recent Governor Replacement & Adjustments.Close Adherence to QA Procedures Will Prevent Recurrence
05000213/LER-1976-015-03, /03L-0:on 760629,abnormal Pressure Noted on Waste Gas Decay Tank TK-6013.Caused by Rupture Disk Rupture at 52 Psig,Rather than 225 Psig.Rupture Disk Replaced & Plant Design Change Prepared to Relocate Rupture Disk
05000029/LER-1976-003-01, /01T-0:on 760513,review of ECCS Analysis Found Error in Accident Analysis.Caused by Error in Assumption of Accident Analysis.Reanalysis Performed.Proposed Change to Tech Specs Submitted
05000298/LER-1980-040-03, /03L-0:on 801017,during Normal Operation,Auxiliary Switch Failed to Return to Normal Position When 4160-volt Breaker Egi Tripped.Caused by Excessive Friction in Switch Operating Mechanism.Switch & Linkage Will Be Replaced
05000029/LER-1976-010-01, /01T-0:on 760830,during Review of Core 12 Analysis,Error Found in Figure 8-1 of Tech Specs.Caused by Gamma Heating Correction Omitted by Error in Application of Computer Codes
05000324/LER-1981-001-03, /03L-0:on 810129,during Surveillance Testing, HPCI Sys Initiation Reactor Level Switch Actuated at Simulated Level Above Tech Spec.Caused by Components Slipping Due to Loose Set Screws on Actuator Pointers
05000368/LER-1980-033-03, /03L-0:on 800530,during Mode 1 Operation,Plant Protection Sys C High S/G Delta P Trip Was Bypassed.Caused by Failed Power Supply on Bistable Card.Bistable Card Replaced & Plant Protection Sys Tested
05000302/LER-1978-034-03, /03L-0:on 780621,decay Heat Removal Flow Control Valve DHV-111 Failed to Respond to Open Command After Being Closed to Check for Low Pressure Injection.No Apparent Cause.Remote Control Immediately re-established
05000338/LER-1979-009-03, /03L-0 on 790212:during Normal Operation,Snubber Support for C Steam Generator Atmosphere Discharge Line Found Damaged.Caused by Use of Support as Anchor for Chain Fall.Support Replaced
05000325/LER-1980-020-03, /03L-0:on 800206,during Normal Shift Turnover, Discovered RIP Valves for Containment Particulate & Gaseous Radioactivity Monitoring Sys Closing.Caused by Isolation of Valves During Penetrant Test
05000313/LER-1980-001-03, /03L-0:on 800114,while Performing Surveillance Test,Hydrogen Purge Supply Isolation Valve CV-7444 Failed to Close.Caused by Oxidation on Torque Switch Contacts, Resulting in High Resistance to Closure.Contacts Cleaned
05000029/LER-1980-003-03, /03L-0:on 800118,while Performing Radioactive Source Inventory & Leak Testing Procedure,Discovered That 121.8 Uci of Cs-137 Sealed Source Had Not Been Inventoried or Leak Tested Since 781213.Caused by Procedural Failure
05000324/LER-1979-065-03, /03L-0 on 790803:during Normal Surveillance of Control panel,2-CO-CR24 Points 1-4 Printed Erratically. Caused by Air Leakage Around Cell.Duct Seal Applied Around Cell Penetrations.Cells to Be Replaced in Sept 1979
05000368/LER-1979-052-03, /03L-0 on 790708:core Protection Calculator B Failed Causing Low DNBR & High Linear Power Density Trips in Plant Protection Sys B.Caused by Lost Bit in High Core Memory Due to Failed Air Conditioner in Computer Room
05000338/LER-1979-032-03, /03L-0 on 790312:containment Vacuum Pump Suction Valve TV-CV150A Would Not Remain Closed When Operated from Control Room.Caused by Relay Sticking in Energized Position.Relay Repaired & Tested Satisfactorily
05000289/LER-1977-021-01, /01T:on 770726,during Normal Operation,Radiation Monitor RM-A2 Failed & Atmosphere Sampling of Reactor Bldg Not Performed.Caused by Improper Reassembly Following 770725 Surveillance Test.Monitor Repaired.Procedure to Be Revi
05000289/LER-1977-013-04, /04T:on 770523,during Normal Operation,Waste Concentration in River Water Discharge Found in Excess of Designated Max.Caused by Slug of Suspended Solids Breaking Loose During Sampling.Discharge Terminated
05000289/LER-1977-023-01, /01T:on 770926,during Heatup Operation Both Doors of Reactor Bldg Emergency Personnel Access Hatch Open Simultaneously.Caused by Failure of Interlock,Poor Hatch Design & Operator Error.Addl Interlock to Be Added
05000289/LER-1977-020-04, /4T:on 770719,during Passage of Storm Front,Station River Water Discharge Temp Fell to in Excess of 3 F Below Inlet Temp.Caused by Storm Front.A & B Mechanical Draft Cooling Fans Stopped
05000289/LER-1977-019-03, /03L:on 770713,during Normal Operation,Leak in Miscellaneous Waste Evaporator Feed Tank Immersion Heater Shorted Out Heater & Feed Pump.Caused by Leak in Temp Probe on Heater.Heater Replaced & Operating Procedure Modified
05000325/LER-1979-007-03, /03L-0 on 790109:during Sys Component Test, Residual Heat Removal Pump D Would Not Start.Caused by Motor Switch Being in Off Position
05000295/LER-1979-094-01, /01T-0:on 791228,pH of Effluent from Waste Water Treatment Facility Measured in 4.1-4.77 Range.Caused by Acidic Solution Leak in Waste Neutralization Tank Via Bad Packing Glands.Tank Neutralized
05000254/LER-1979-042-03, /03L-0:on 791214,while Performing MSIV Closure Timing Surveillance,Ao 1-203-1C Found to Close in 5.2-s. Caused by Varied Speed Control Valve Adjustment on Hydraulic Control Cylinder.Valve Adjusted
05000368/LER-1979-037-03, /03L-1 on 790514:supply Valves 2CV-1039-2 & CV-1076-2 to Steam Generator 2E24B Would Not Respond During Mode 3 Operation.Caused by Blown Fuse & Stuck Relay.Repairs Made & Valves Proven Operable
05000324/LER-1979-059-03, /03L-0 on 790718:discovered Low Fluid Level on Snubber 2E51-40SS87,RCIC Pump Suction.Caused by Leaking Seals.Snubber Replaced
05000338/LER-1980-008-01, /01T-0:on 800111,during Review for IE Circular 78-08,S&W Found Control Room Air Conditioning Chiller Units Control Panel Not Qualified to Seismic Category I Requirements.Cause Unknown.Vendor Reviewing Components
05000281/LER-1975-010-01, /01T:on 750624,svc Water Pump 2-SW-P-4B Developed Seal Leak.Caused by Electrical Short in Motor Operator.Pump Leak & Motor Operator Repaired
05000281/LER-1975-011-01, /01T:on 750630,4 Kv Undervoltage Protection Inoperable.Caused by Blown Fuse.Fuses Replaced
05000281/LER-1975-012-01, /01T:on 750706:main Steam Line Trip Valve in Steam Line B Closed,Causing Closure of Trip Valves a & C & Reactor Trip.Caused by Faulty Piston O-ring.O-ring Replaced & Air Lines Cleared of Debris
05000280/LER-1975-018-01, /01T:on 750924,loop a Instrumentation Drifted Low. Caused by High Moisture Content in Containment Atmosphere. RTD Will Be Repaired or Replaced
05000280/LER-1975-019-01, /01T:on 750925,loop B Temperature Change Instrumentation Drifted Low.Caused by Moisture Content of Containment Atmosphere.Spare RTD Placed in Svc & Shutdown Terminated
05000281/LER-1975-017-01, /01T:on 751003,loop C Leg RTD Failed Low,Causing Protection Signals to Fail Low.Caused by Incorrect Ohmic Characteristic of Connected RTD & Spare.Failed Instruments Replaced
05000281/LER-1975-018-01, /01T:on 751009,steam Generator Level Transmitter Isolation Valve Body Bonnet Leak Wetted Down RPI Cabling, Causing Grounds & Erratic Indication for 24 Different Rods. Caused by Water Spray
05000280/LER-1975-016-01, /01T:on 750822,Channel II Protection Drifted in Nonconservative Direction.Caused by Incorrect Resistance of Hot Leg Resistance Temp Detector (Rtd).Packing Replaced & RTD Ohmic Characteristic Returned to Normal
05000281/LER-1975-016-01, /01T:on 750823,low Level Alarm on Boric Acid Tank C Received.Caused by Installation of Carbon Steel Rather than Stainless Steel 304 Flanges & Pipe of Spool Piece.All Improper Installations Will Be Replaced
05000281/LER-1975-021-01, /01T:on 751219,channel 3 for Over Temp Indicated 132% While Channels 1 & 2 Indicated 118%.Cause Unknown. Channel Calibr & Returned to Svc
05000280/LER-1975-027-01, /01T:on 751205,uncontrolled & Unplanned Release of Low Level Radioactive Matl Occurred.Caused by Primary Grade Water Tank 1-PG-TK-1A Overflow Due to Operator Error. Administrative Action Taken
05000281/LER-1976-010-03, /03L:on 760621,loss of Voltage Alarm Received on Power Range Nuclear Instrument Channel 42.Caused by Failure of 25-volt Power Supply.Power Supply Replaced & Channel Calibr
05000280/LER-1975-015-01, /01T:on 750803,leaking Fitting on Overhead Gas Compressor B Resulted in Unplanned Release of Radioactive Matl from Site.Caused by Loose Fitting.Leaking Fitting Repaired
05000000/LER-1977-012, :on 770620,during Investigation of Cycle 5 Max Critical Power Ratio Limits,Ge Found That Pump Trip Delay Time Assumed in Original Cycle 5 Transient Analysis Not Appropriate.Amend Request Will Be Submitted
05000263/LER-1976-014, :on 760811,during Startup,Primary Containment Dioxide Concentration Not Reduced to Less than 5% within 24 H After Going Into Run Mode.Caused by Failed Metal Bellows Co Model MN-115 Pump Bellows
05000263/LER-1976-016, :on 760828,during Insp of Condenser area,1-inch Elbow Found Leaking on HP Turbine Inlet Steam Line U-bend Drain Line.Erosion of Wall Caused by Hot Steam Flashing After Passing Through Orifice
05000261/LER-1976-015, :on 760817,auxiliary Feedwater Pump Discharge Valve V2-16A Failed to Open as Required.Caused by Valve Binded to Seat.Larger Capacity to Be Installed
05000271/LER-1975-018, :on 750901,steam Supply Isolation Valve 13-15 Would Not Fully Close.Caused by Tightening Valve Package During Maint Which Caused Packing to Swell.Bolting Replaced & Motor Operator Reinstalled
05000271/LER-1975-022, :on 751109,during Cold Shutdown,Valve 10-25B Control Room Position Indication Lights Indicated Valve Cycling from Full Open to Full Closed Position.Cause Unknown.No Corrective Actions Taken
05000261/LER-1976-020, :on 761117,small Pinhole Leaks Found on Three Canopy Seal Welds.Caused by Weld Degradation.Affected Surface Cleaned,Repair Welded & Nondestructively Examined
05000271/LER-1976-008-03, /03L:on 760415,LPCI Sys a Declared Inoperable & Alternate Testing Commenced.Caused by Inability to Guarantee Valve RHR-25A Operability Due to Past Problems W/Valve Body Shrinkage.Valve Reset
05000271/LER-1976-014-03, /03L:on 760519,level Switch 23-91A Would Not Actuate at Tech Spec Trip Level Setting of 2 Inches.Caused by Accumulation of Scale & Corrosion Inside Switch Chamber. Float Tapped & Repeatedly Flushed
05000271/LER-1976-016-03, /03L:on 760614,level Switch 23-91A Would Not Actuate at Tech Spec Trip Level Setting.Caused by Stuck Float Inside Level Switch Chamber.Switch Chamber Flushed, Causing Float to Become Freed & Operable
05000271/LER-1976-018-01, /01T:on 760629,control Rod Block Associated W/One Control Rod Withdrawal Permit Circuit Found Inoperable. Caused by Position Indicating Switch on Rod 22-43 at full-in Position Stuck in Closed Position
05000267/LER-1976-003-01, :on 761220,during Weekly Surveillance Test, Clicking Sound at Engine & Intermittent Emergency Fire Water Pump 1B Run Alarm Detected.Caused by Failure of Drive Cable Due to Normal Wear.Cable Replaced
05000244/LER-1976-014-03, /03L-0:on 760412,N44 Power Range Detector High Voltage Power Supply Failed.Cause Under Investigation
05000260/LER-1983-028-03, /03L-0:on 830526,during Normal Operation,Hpci Sys Declared Inoperable Due to Blown Inverter Fuse.Fuse Replaced.Hpci Turbine Control Valve Failed to Open Due to Misadjusted Rod.Rod Adjusted
05000395/LER-1983-029-03, /03L-0:on 830320,w/reactor Bldg Purge Initiated, Radiation Monitor RM-A4 Read Higher than Normal Pump RM-A4 & Detector Secured to Change Filter,Leaving Purge Unmonitored for 5 Minutes.No Activity Released During Event