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| Issue date | Title | Topic | |
|---|---|---|---|
| ML17335A764 | 22 October 1998 | LER 98-004-00:on 980923,inadvertent Actuation of Efs Occurred During Surveillance Testing.Caused by Personnel Error.Personnel Involved with Event Were Counseled & Procedure Changes Were Implemented.With 981022 Ltr | |
| ML20045B302 | 11 June 1993 | LER 93-001-00:on 930513,discovered That One Channel of Rvlms Inoperable Since Probe Replaced in Oct 1992.On 930507, Discovered That Two Sensors in Rvlms Indicating Wet.Caused by Design Error.Wiring Polarity corrected.W/930611 Ltr | Reverse polarity |
| ML20024H228 | 21 May 1991 | LER 91-003-00:on 910421,actuation of EFW Sys During Plant Heatup Occurred Due to Low Once Through Steam Generator Level.Caused by Leaking Feedwater Recirculation Valve.Plant Startup Procedure OP 1102.02 Will Be revised.W/910521 Ltr | |
| ML20024H086 | 10 May 1991 | LER 91-002-00:on 910410,inadvertent Actuations of Combined Control Emergency Ventilation Sys Occurred.Caused by Transient Noise Spike.Mod Will Be Completed by 910531 to Install Time Delay in Actuation circuitry.W/910510 Ltr | |
| ML20024G978 | 10 May 1991 | LER 90-004-01:on 900531,discovered Degraded Fire Barrier Penetration During Insp Per Generic Ltr 86-10.Caused by Failure to Identify Adequate Fire Barrier Seal During 1983 Plant Walkdown.Fire Watch posted.W/910510 Ltr | Fire Barrier Continuous fire watch Fire Watch |
| ML20029C377 | 22 March 1991 | LER 91-006-00:on 910222,core Protection Calculator Reactor Coolant Sys Flow Channels Not Being Calibrated within Tech Spec.Caused by Personnel Error.Operations Manager Counseled Operators Involved in event.W/910322 Ltr | |
| ML20029B133 | 27 February 1991 | LER 91-004-00:on 910125,control Room Radiation Monitor Alarm/Trip Setpoint Greater than Normal.Caused by Personnel Error.Operations Manager Will Counsel Shift Supervisors & Night Order Will Be posted.W/910227 Ltr | Time of Discovery |
| ML20028H684 | 21 January 1991 | LER 90-021-00:on 901222,potential RCS Leak Noted in Area of Pressurizer Upper Level Instrument Nozzle.Caused by Pure Water Stress Corrosion Cracking.New Nozzle Installed Into Penetration from Shell OD.W/910121 Ltr | Nondestructive Examination Pressure boundary leak |
| ML20043C680 | 31 May 1990 | LER 89-025-01:on 891221,identified That Portion of Wall Located in Auxiliary Bldg Had Not Been Previously Identified as Tech Spec Fire Barrier.Caused by Personnel Error.Wall Being Upgraded to Tech Spec status.W/900531 Ltr | Time of Discovery Fire Barrier Fire Watch |
| ML20043C378 | 30 May 1990 | LER 90-012-00:on 900430,18 Month Channel Calibr of Liquid Radwaste Effluent Line Flow Monitor Not Performed as Required.Caused by Inadequate Controls to Ensure Followup Actions Taken in Timely Manner.Amends revised.W/900530 Ltr | |
| ML20043C036 | 23 May 1990 | LER 90-003-01:on 900423,discovered That Incorrect Monitoring Instrumentation for Radiological Effluent Ventilation Sys Utilized to Comply W/Tech Specs.Caused by Mgt Oversight.Logs Process Monitors Will Not Be used.W/900523 Ltr | |
| ML20043A741 | 17 May 1990 | LER 90-004-01:on 900212,discovered That Backwater Valve in Floor Drain Pipe in Emergency Feedwater Pump Room Missing. Caused by Inadequate Configuration Control.Backwater Pumps Installed & Will Be Included in Maint program.W/900517 Ltr | Safe Shutdown Time of Discovery |
| ML20042F768 | 1 May 1990 | LER 90-002-01:on 900131,errors Identified in Calculation Used to Establish Calibr Tables for Steam Generator Water Level Transmitters.Errors in Original Calculation Not Identified.Calibr Procedures revised.W/900501 Ltr | Safe Shutdown Time of Discovery |
| ML20042F775 | 1 May 1990 | LER 90-010-00:on 900401,personnel Failed to Complete Control Element Assembly Position Log.Caused by Surveillance Program Deficiencies & Lack of Mgt Involvement.Shift Briefing Completed & Procedure Change incorporated.W/900501 Ltr | Missed surveillance |
| ML20042E198 | 10 April 1990 | LER 90-008-00:on 900311,determined That Seal Leakage Test for Containment Personnel Air Lock Had Not Been Performed, Per Tech Specs.Caused by Personnel Error.Procedure Revs Initiated & Personnel counseled.W/900410 Ltr | |
| ML20012F505 | 5 April 1990 | LER 89-027-00:on 891005,determined That Leakage Rate for Containment Isolation Check Valve in Excess of Leakage Rate Allowed Per Tech Specs.Caused by Loose Weld Slag in Valve Seat Area.Valve Cleaned & reassembled.W/900405 Ltr | |
| ML20012F503 | 5 April 1990 | LER 90-007-00:on 900306,RCS Charging Line Rendered Inoperable Due to Deficient Piping Support Weld.Caused by Inadequate Work Controls & post-installation Insp Processes. Field Walkdowns & Weld Insps initiated.W/900405 Ltr | Time of Discovery |
| ML20012F574 | 4 April 1990 | LER 90-006-00:on 900305,instrumentation Channels Declared Inoperable,Resulting in Manual Actuation of Reactor Protection Sys.Caused by Procedural Deficiencies.Functional Tests of Log Power Level Channels performed.W/900404 Ltr | Shutdown Margin Anticipated operational occurrence Fuel cladding |
| ML20012C722 | 14 March 1990 | LER 90-004-00:on 900212,identified That No Backwater Valve Located in Floor Drain Pipe in One of Emergency Feedwater Pump Rooms.Caused by Inadequate Configuration Control. Valves Installed on 900215.W/900314 Ltr | Safe Shutdown Time of Discovery |
| ML20012C182 | 12 March 1990 | LER 85-029-00:on 850520,unusual Motor Vibrations Identified on Svc Water Pump 2PM4A.On 861028,high Vibrations Noted on Upper Motor Bearings of Pump 2PM4B.Caused by Improper Installation.New Bearings installed.W/900312 Ltr | |
| ML20012B727 | 8 March 1990 | LER 89-049-01:on 891220,discovered That Okonite T-95 Tape Not Used to Tape Internal Motor Lead Connections for Main Feedwater Containment Isolation Valves.Caused by Personnel Error.Valves Taped According to Design drawing.W/900308 Ltr | |
| ML20012B570 | 5 March 1990 | LER 90-003-00:on 900201,failure to Perform Monthly Source Check Surveillance on Three Radiation Process Monitors Occurred.Caused by Inadequate Procedure Change by Personnel. Source Check on Monthly Basis implemented.W/900305 Ltr | |
| ML20011F674 | 2 March 1990 | LER 90-002-00:on 900131,errors Identified in Calculation Used to Establish Calibr Tables for Steam Generator Water Level Transmitters.Caused by Incorrect Static Pressure Assumption.Trip Setpoint Bistable increased.W/900302 Ltr | Safe Shutdown Time of Discovery |
| ML20011F678 | 1 March 1990 | LER 89-026-00:on 891112,gaps in Piping Supports on Supply & Return Piping for Containment Coolers Identified.Caused by Inadequate Design Technique Used in Original Support Design. Shims Added Before Restart from outage.W/900301 Ltr | Time of Discovery |
| ML20011F583 | 27 February 1990 | LER 89-022-01:on 891114,normal Offsite Power Feeder Breaker to 4,160-volt Ac ESF Bus Opened,Resulting in Loss of Power to Bus 2A3.Caused by Inadequate post-maint Test Controls. Test Switch Opened & Job Order changed.W/900227 Ltr | |
| ML20011F731 | 23 February 1990 | LER 90-001-00:on 900126,identified That Required Visual Insps of Containment Bldg After Entry Made Not Documented as Being Performed.Caused by Inadequate Procedural Guidance. Administrative Controls to Be established.W/900226 Ltr | |
| ML20006D739 | 6 February 1990 | LER 89-034-01:on 891031,determined That Tech Spec 3.9.1 Had Likely Been Violated Re Independent Circuits of Control Room Emergency Air Conditioning Sys.Caused by Inadequate Guidance Re Equipment Svc Removal.Procedures revised.W/900206 Ltr | Time of Discovery |
| ML20011E237 | 31 January 1990 | LER 89-012-01:on 890626,RCS Backleakage Through Safety Injection Sys Check Valve Occurred Three Times.Caused by Missing Rollpins Which Connect Valve Disc to Valve Disc Shaft.Rollpins Replaced & Valves reassembled.W/900131 Ltr | Shutdown Margin Hydrostatic |
| ML20011E229 | 31 January 1990 | LER 89-039-01:on 891116,discovered That Door for Upper North Electrical Penetration Room Open & Latch Mechanism Missing. Caused by Abnormally High Differential Pressure Across Door. Ventilation Sys Flow Balance performed.W/900131 Ltr | |
| ML20011E145 | 30 January 1990 | LER 89-024-00:on 891231,loose Terminal in Feedwater Control Sys Cabinet Resulted in Reactor Trip.Caused by Loose Connection on Terminal.Loose Connection Reterminated properly.W/900130 Ltr | |
| ML20006C145 | 29 January 1990 | LER 89-048-00:on 891228,automatic Reactor Trip & ESF Actuation Occurred as Result of Loss of All Main Feedwater Flow Due to Inadvertent Tripping of Main Feedwater Pump. Caused by Personnel error.O-rings replaced.W/900129 Ltr | |
| ML19354E333 | 22 January 1990 | LER 89-025-00:on 891221,two Piping Penetrations Located in Barrier Not Surveilled as Required by Tech Specs.Caused by Personnel Error.Fire Watch Posted When Necessary Per Tech Spec.W/900122 Ltr | Time of Discovery Fire Barrier Fire Watch |
| ML20006A866 | 22 January 1990 | LER 89-041-00:on 891221,automatic Actuation of Emergency Feedwater Sys Initiated.Caused by Lack of Adequate Procedural Guidance.Valve Positioners CV-2623 & CV-2673 Adjusted & Guidance Procedures developed.W/900122 Ltr | |
| ML20006A867 | 22 January 1990 | LER 89-042-01:on 891209,inadvertent Actuation of Control Room Emergency Ventilation Sys Occurred.Caused by Keying of Hand Held Radio in Vicinity of Chlorine Monitors by Technician.Technician counseled.W/900122 Ltr | |
| ML20005F155 | 18 January 1990 | LER 89-023-01:on 891117,noted That Channel a Not Responding to Change in Power Level & Declared Inoperable.Caused by Defective Preamplifier.Evaluation of Sys Design & Channel Functional Test initiated.W/900108 Ltr | Anticipated operational occurrence Fuel cladding |
| ML20006B646 | 18 January 1990 | LER 89-047-00:on 891219,RCS Temp Increased Above 250 F W/ Oxygen Concentration Greater than Tech Specs Limit.Caused by Inadequate Procedural Guidance.Plant Startup Procedure Revised to Require Chemistry Dept signoff.W/900118 Ltr | |
| ML19354D829 | 15 January 1990 | LER 89-044-00:on 891214,incorrect Assumptions & Calculational Errors Identified for Low Pressure Injection & Reactor Bldg Spray Pumps When Aligned to Take Suction from Reactor Bldg sump.W/900115 Ltr | Time of Discovery |
| ML20005G168 | 9 January 1990 | LER 89-045-00:on 891210,discovered That U-bolt Supports on Two Containment Isolation Valves in Containment Bldg Not Installed & Pressurizer Sample Lines & Valves Considered Inoperable.Missing U-bolts installed.W/900109 Ltr | Time of Discovery |
| ML20005F148 | 8 January 1990 | LER 89-042-00:on 891209,inadvertent Actuation of Control Room Emergency Ventilation Sys Occurred.Caused by Keying of Hand Held Radio in Vicinity of Chlorine Monitors by Technician.Technician counseled.W/900108 Ltr | |
| ML20005F157 | 8 January 1990 | LER 89-043-00:on 891208,discovered That Approx 50% of One Nut Ring Half Beneath Reactor Vessel Nozzle Flange Corroded Away.Caused by Gradual Deterioration of Gasket Matl.Design Change implemented.W/900108 Ltr | Boric Acid Time of Discovery |
| ML20005F207 | 4 January 1990 | LER 89-040-00:on 891205 & 06,automatic Actuations of Emergency Diesel Generator Occurred as Result of Loss of Power to 480-volt ESF Bus.Caused by Personnel Error During Bus Transfer.Mgt Briefings conducted.W/900104 Ltr | |
| ML20005F047 | 3 January 1990 | LER 89-046-00:on 891204,reactor Bldg Isolation Valves Rendered Inoperable Due to Deficient Welds on Piping Supports Which Were Installed During Initial Plant Const. Deficient Supports Repaired Prior to restart.W/900103 Ltr | Time of Discovery |
| ML20011D252 | 18 December 1989 | LER 89-039-00:on 891116,discovered That Door for Upper North Electrical Penetration Room Open & Missing Latch Mechanism. Caused by Extensive Use During 56-day Refueling Outage.More Frequent Insps of Door Condition to Be done.W/891218 Ltr | |
| ML20011D250 | 18 December 1989 | LER 89-023-00:on 891117,approach to Criticality Commenced After Seventh Refueling Outage W/Logarithmic Power Level Channels Inoperable.Caused by Electrical Noise in Circuitry. Defective Preamplifier replaced.W/891218 Ltr | Anticipated operational occurrence Fuel cladding |
| ML19351A673 | 14 December 1989 | LER 89-022-00:on 891114,inadequate post-maint Test Controls Resulted in de-energizing 4,160 Volt Ac ESFs Electric Bus Uexpectedly.Caused by Inadequate post-maint Test Controls. Job Order Instructions changed.W/891214 Ltr | |
| ML19354D552 | 14 December 1989 | LER 89-038-00:on 891114,reactor Trip Occurred as Result of Inadvertent Closure of Main Feedwater Isolation Valve.Caused by Personnel Error.Disciplinary Action Taken Against Individual & Senior Mgt Personnel Put on shift.W/891214 Ltr | |
| ML19351A465 | 11 December 1989 | LER 89-021-00:on 891111,when Low Level Radwaste Water in Waste Condensate Tank Aligned to Be Released,Discovered That Radiation Monitor Inoperable for Duration of Release.Caused by Personnel Error.Procedure revised.W/891211 Ltr | |
| ML19332F617 | 11 December 1989 | LER 89-037-00:on 891110,reactor Trip Occurred as Result of Inadvertent Grounding of Reactor Protection Sys Power Supply During Surveillance Testing.Caused by Inadequate Procedure. Procedures revised.W/891211 Ltr | |
| ML20005D682 | 1 December 1989 | LER 89-005-01:on 890518 & 25,damping Board Removed from Penetration Containing Cable Tray.On 890531,voids Noted in Penetration Seals.Caused by Erroneous Vendor Procedures. Penetrations Restored & Procedures revised.W/891201 Ltr | Time of Discovery Fire Barrier Continuous fire watch Fire Watch |
| ML19332E861 | 30 November 1989 | LER 89-034-00:on 891031,control Room Emergency Air Conditioning Sys Rendered Inoperable Due to Removing Independent Circuits from Svc.Caused by Inadequate Guidance.Procedures Revised & Circuits flagged.W/891130 Ltr | Time of Discovery |