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 Issue dateTitleTopic
ML17326A20123 August 1999LER 99-004-00:on 990724,reactor Tripped Due to Main Transformer Bushing Flashover.Plant Was Brought to SS & Components Were Tested & Performed Satisfactorily.With 990823 LtrSafe Shutdown
High winds
ML20029C73222 April 1994LER 94-004-00:on 940221,discovered Corrosion of Three Nuts on One of Incor Instrumentation Reactor Vessel Head.Caused by Increase of Wet Boric Acid.Leaking Flanges Repaired.W/ 940422 LtrBoric Acid
ML20046B47330 July 1993LER 93-005-00:on 930630,TS 3.0.3 Entered Due to Both Containment Spray Sys Inoperable.Replaced CCW Outlet Valve Actuator Connecting Link Assembly from Number 11 SDC Heat exchanger.W/930730 Ltr
ML20046A49122 July 1993LER 93-003-00:on 930625,SG Tripped Due to Low Water Level. Caused by Insufficient Feedwater Addition Due to Inadequate Communication.Reemphasis on Improved Communication Stressed. W/930722 LtrPower change
ML20045G8619 July 1993LER 93-003-00:on 930610,dual Unit Trip Occurred Due to Partial Loss of Offsite Power.Flashover Protection Relay for Breaker 552-61 Replaced & Training for Personnel W/ Access to Relays Will Be reinforced.W/930709 LtrEmergency Lighting
ML20045G7288 July 1993LER 93-002-00:on 930608,inadvertent Arw Actuation Sys & RPS Actuations Experienced During Performance of Awf Sys Large Flow Surveillance Testing.Caused by Failure to Note Differential Pressure Condition.Valve opened.W/930708 Ltr
ML20045G8668 July 1993LER 93-004-00:on 930611,reactor Tripped Due to Turbine Trip Resulting from Inadequate Procedure.Procedure Changes Made to Open Appropriate FW Heater High Level Dump Valves During Plant startup.W/930708 Ltr
ML20045E73629 June 1993LER 93-002-01:on 930205,software Vendor Discovered Error in User Manual for Updating Basss data-input Library.Caused by Failure of QA Procedures to Require Independent Review of User Manuals.Manual Surveillances performed.W/930629 LtrMissed surveillance
ML20029B12628 February 1991LER 91-001-00:on 910129,tubing in Air Start Sys for Emergency Diesel Generator Failed During Seismic Event. Caused by Error in Design of EDG Air Start Sys.Permanent Mod to Sys installed.W/910228 LtrSafe Shutdown
Time of Discovery
Temporary Modification
ML20028H80124 January 1991LER 90-002-01:on 900116,determined That 891211 Reconstitution of More than One Spent Fuel Assembly Per Time in Violation of Fuel Handling Incident Safety Analysis. Caused by Deficient procedure.W/910124 Ltr
ML20044A18620 June 1990LER 87-002-01:on 861203,section of Thin Wall Found on Main Steam Line W/Readings Below Allowable Min of 0.95 Inches. Caused by Grinding of Edge of Pipe to Achieve Proper fit-up for Welding.Relief from IWB-3610 granted.W/900620 LtrFinite Element Analysis
ML20043G10713 June 1990LER 89-019-01:on 891128,determined That for Approx 10 Yrs, from 1979-1989,requirement to Lock HPSI Discharge Header Isolation Valves Shut Not Implemented.Caused by Inadequate Mgt Attention.Test Procedures modified.W/900613 LtrTime of Discovery
ML20043F1224 June 1990LER 90-017-00:on 900505,pin Hole Leak Observed in Discharge Piping of Saltwater Pump 13.Caused by Localized Corrosion. Leaking Spool Piece Removed & Blank Flange Installed. W/900604 Ltr
ML20043A78721 May 1990LER 90-016-00:on 900421,determined That Waste Gas Decay Tank (Wgdt) 13 Discharged Instead of (Wgdt) 11 for Discharge Permit Issued.Caused by Inadequate Communications.Training Performed for Operators Re event.W/900521 Ltr
ML20043A34414 May 1990LER 90-014-00:on 900413 & 19,unit Entered Tech Spec Limiting Condition of Operation 3.0.3 Due to Potential Inoperability of Three Out of Four Reactor Protection Sys Delta T Power Channels.Caused by Lack of Procedure guidance.W/900514 Ltr
ML20043A34014 May 1990LER 90-013-00:on 900413,determined That Axial Shape Index Channels Out of Spec & Inoperable.Caused by Inadequate Understanding of Design Basis for Excore/Incore Comparison. Design Basis for Excore/Incore improved.W/900514 Ltr
ML20042G4527 May 1990LER 90-015-00:on 900407,discovered That Relay Contact Which Actuates Reactor Trip Breaker Shunt Trip Not Adequately Functionally Tested.Caused by Failure to Examine Circuit in Detail When Test developed.W/900507 Ltr
ML20042F5804 May 1990LER 90-012-00:on 900406,identified That Procedure for LOCA Would Not Ensure post-LOCA Core Flush Would Be Initiated in Time to Prevent Boron Precipitation.Caused by Personnel Error.Configuration Mgt Program strengthened.W/900504 LtrBoric Acid
ML20012E99329 March 1990LER 90-008-00:on 900227,determined That Surveillance Procedure M-280-0 Did Not Include Steps to Fully Test Control Room Recorder for Hydrogen Analyzers.Caused by Personnel Error.Procedure Revised on 900308.W/900329 LtrGrab sample
ML20012F00028 March 1990LER 89-006-01:on 890508,containment Iodine Filters Outside Design Basis Due to Equipment Qualification.Recalculation of Total Integrated Radiation Dose to Cables for Filter Fans Demonstrated Cable qualified.W/900328 Ltr
ML20012E99528 March 1990LER 89-014-01:on 890723,determined That Salt Water Header Not Capable of Withstanding Seismic Event Intact.Caused by Inadequate Welding of Blind Spool Pieces in Pipe.Insp Revealed Spools Capable as installed.W/900328 Ltr
ML20012E01026 March 1990LER 90-009-00:on 900224,failure to Meet Action Requirement Re Tech Spec 3.7.12.Caused by Personnel Error.Cables Removed from Doorway in Charging Pump Room & Not Allowed to Be Placed in doorway.W/900326 LtrTime of Discovery
Fire Barrier
Continuous fire watch
Hourly Fire Watch
Scaffolding
ML20012C49715 March 1990LER 90-007-00:on 900216,discovered That Supervised Circuits Associated W/Fire Detection Instruments Located in Reactor Coolant Pump Bays Not Been Included in Surveillance Test Procedure.Caused by Personnel error.W/900315 LtrFire Watch
ML20012C48612 March 1990LER 90-006-00:on 900209,determined That Four Fire Dampers Missing.Caused by Not Identifying Penetrations as Requiring Dampers When Fire Hazards Analysis of Plant Conducted.Hourly Fire Watch Continued.Missing Dampers installed.W/900312 LtrTime of Discovery
Fire Barrier
Fire Watch
Hourly Fire Watch
ML20012B89912 March 1990LER 89-023-01:on 891220,determined That Pipe Rupture in nonsafety-related Svc Water Subsystem Could Result in Rapid Draining of Subsystems That Serve Auxiliary Bldg.Task Force Formed to Determine Corrective actions.W/900312 LtrSafe Shutdown
Safe Shutdown Earthquake
Probabilistic Risk Assessment
Earthquake
ML20012B4226 March 1990LER 89-012-01:on 891227,core Alterations Performed W/Only One of Two Containment Vent Valves Closed.Caused by Procedural Deficiency.Procedures Revised to Include Valve & Surveillance Test Program Instruction revised.W/900306 Ltr
ML20011F27027 February 1990LER 90-001-01:on 900109,determined That Surveillance Tests Used to Perform Channel Calibr Tests for Acoustic Flow Monitoring Devices Inadequate.Caused by Personnel Error & Inadequate Procedures.Swapped Leads restored.W/900227 Ltr
ML20011F20927 February 1990LER 89-026-00:on 891128,determined That Particulate Levels in Samples Taken from Lower Third of Tanks Exceeded Allowable Limits.Caused by Inadequate Sampling Technique. Tanks Cleaned & Filled W/Clean fuel.W/900227 Ltr
ML20006F86022 February 1990LER 90-004-00:on 900123,discovered Fire Barrier Penetration Seal Open for Indeterminate Time W/O Performing Tech Spec 3.7.12.a Required Actions.Caused by Personnel Error. Temporary Fire Seal installed.W/900222 LtrTime of Discovery
Fire Barrier
Continuous fire watch
Fire Protection Program
Hourly Fire Watch
ML20006E0528 February 1990LER 90-001-00:on 891221,discovered That Acoustic Indications for One PORV & One Safety Valve Were Reversed During Surveillance Test.Caused by Personnel Error.Swapped Leads Restored to Proper configuration.W/900208 Ltr
ML20006B48026 January 1990LER 89-022-00:on 891227,core Alterations Performed W/Only One of Two Containment Vent Valves Closed,Violating Tech Specs.Caused by Procedural Deficiency.Surveillance Test Procedure Revised to Include Deleted valves.W/900126 Ltr
ML19354D89317 January 1990LER 89-024-00:on 891218,determined That Wires Which Connect Actuation Device Logic Relay Contacts to Remainder of Circuit Not Tested During Channel Calibr Test.Caused by Inadequate Test.Test Program Upgrade underway.W/900117 Ltr
ML20005F19210 January 1990LER 89-025-00:on 891208,Tech Spec Action Statement Entered When Ventilation Ducts Penetrating Fire Barrier Could Not Be Accessed to Determine If Fire Dampers Installed.On 891211, Fire Watch Missed.Caused by Personnel error.W/900110 LtrFire Barrier
Fire Watch
Hourly Fire Watch
ML20005E39728 December 1989LER 89-019-00:on 891128,discovered That HPSI Discharge Header Isolation Valves Not Locked Shut When RCS in Water Solid Condition,Resulting in Operation Outside Design Basis. Procedure Revised to Require Valves closed.W/891228 LtrTime of Discovery
ML19351A45513 December 1989LER 89-020-00:on 891113,determined That Some Solenoid Valves & Valve Power Supplies for Saltwater Sys May Not Be Able to Perform Design Function After Design Basis Seismic Event. Cause Undetermined.Power Supplies upgraded.W/891213 LtrHigh Radiation Area
Ultimate heat sink
ML20005D6616 December 1989LER 89-018-00:on 891106,discovered That Many Air Operated Control Valves & piston-operated Dampers Which Utilize safety-related Air Accumulators Would Not Have Performed as Expected After Loss of air.W/891206 LtrSafe Shutdown
High Radiation Area
Ultimate heat sink
ML19325F39510 November 1989LER 89-002-01:on 890228,discovered That Fire Barrier Penetration Inoperable & Action Statement Requirements Not Satisfied.Caused by Inadequate Administrative Controls. Penetration Returned to Operable status.W/891115 LtrTime of Discovery
Fire Barrier
Continuous fire watch
Hourly Fire Watch
ML19325E8223 November 1989LER 89-007-01:on 890505,evidence of Reactor Coolant Leakage from 120 Pressurizer Vessel Heater Penetrations Discovered. Caused by IGSCC of Inconel 600.All Penetrations Using J-welds & Inconel 600 Visually inspected.W/891103 LtrBoric Acid
Weld Overlay
Pressure boundary leak
ML19324B25127 October 1989LER 89-012-01:on 890720,discovered That Master Solenoid to Switchgear Room Halon Sys Disconnected Since 890629.Caused by Personnel Error Resulting from Lack of Written Procedure. Procedure Revised to Apply Temporary mods.W/891027 LtrTemporary Modification
Fire Protection Program
Fire Watch
Hourly Fire Watch
ML19325C32810 October 1989LER 89-016-00:on 890908,determined That as-found Condition of Resistance Temp Detectors Did Not Match Tested Configuration.Cause Not Stated.Subj Detectors Will Be Sealed,Per Environ Qualification requirements.W/891010 LtrPost Accident Monitoring
ML19325C3709 October 1989LER 89-017-00:on 890907,determined That Discrepancy in Acceptance Criteria of Surveillance Test Procedure M-452-0 Resulted in Failure to Fully Comply W/Requirements of Tech Spec 3.9.12.Main Cause undetermined.W/891009 LtrTime of Discovery
ML20024F37725 August 1983LER 83-044/03L-0:on 830808,diesel Generator 12 Tripped on Low Jacket Cooling Water Pressure While Verifying Operability.Cause Not Stated.Coolant Jacket Vented & Large Amount of Air Found.No Evidence of leakage.W/830825 Ltr
ML20024F57325 August 1983LER 83-040/03L-0:on 830727,control Room Air Conditioner 11 Discovered W/Damaged Condenser Fan.Caused by Loose Set Screws Securing Fan in Position.Set Screws Restored. W/830825 LtrLoctite
ML20024E6764 August 1983Updated LER 83-011/03X-1:on 830207,during Surveillance Testing ESFAS a Logic Sequencer Failed,Rendering Diesel Generator 12 Inoperable.Caused by Intermittent Operation of Module Test Push Button.Part replaced.W/830804 Ltr
ML20024E17214 July 1983Updated LER 81-015/03X-1:on 810226,sample Pump for Control Room Radiation Monitor Found Out of Svc,Rendering Automatic Recirculation of Control Room Ventilation Sys on High Radiation Inoperable.Caused by seizure.W/830714 Ltr
ML20024D0078 July 1983LER 83-035/03L-0:on 830610,during Normal Power Operation,Esf Actuation Sys Channel Zg Steam Generator Level Tripped. Caused by Failed Vitro Isolator Module.Module Replaced.W/ 830708 Ltr
ML20024D0098 July 1983LER 83-033/03L-0:on 830603,fire Detection Instrumentation in Containment Southeast Electrical Penetration Determined Inoperable.Repair Impossible Due to Inaccessability of Protecto wire.W/830708 Ltr
ML20024B82323 June 1983LER 83-029/03L-0:on 830524,during Normal Operation, Surveillance Testing Indicated Neither Spent Fuel Pool Exhaust Fans 11 or 12 Would Maintain Required Negative Pressure.Caused by Clogged HEPA filters.W/830623 Ltr
ML20024C01422 June 1983Updated LER 81-080/03X-1:on 811116,discovered Weep from Cracked Weld on Spent Fuel Cooling Pump Discharge Vent Line 12.Caused by Inadequate Support of Vent Line.Support Assembly installed.W/830622 LtrHydrostatic
ML20024A88816 June 1983LER 83-032/03L-0:on 830523,containment Isolation Sys B Logic Module Would Not Actuate.Caused by Defective Vitro Labs Std Logic Module.Module Replaced.Failed Module Returned to Vitro Labs for Repair & testing.W/830616 Ltr