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| Issue date | Title | Topic | |
|---|---|---|---|
| ML20046C212 | 30 July 1993 | LER 93-004-01:on 930301,confirmed That Channel D Axial Shape Index (Asi) Being Calculated in Reverse Since 921031-930301 Due to Drawing Discrepancies Associated W/Control Channel B. Temporary Mod 92-078 & Standing Order 0-25 Revised | Anticipated operational occurrence Temporary Modification |
| ML20046A869 | 26 July 1993 | LER 93-011-00:on 930624,experienced Reactor Trip Due to Loss of Load.Caused by Lack of Proper Job Planning,Lack of Formal Decision Making Process & Incomplete Communications.Training Will Be Provided to Operations personnel.W/930726 Ltr | Safe Shutdown Slow transfer |
| ML20045H256 | 12 July 1993 | LER 93-010-00:on 930611,1 of 14 Halon Cylinders Did Not Meet Min Pressure Acceptance Criteria Listed in Semiannual Switchgear Rooms Surveillance Test.Caused by Failure of Test to Include Necessary Steps.Cylinder recharged.W/930712 Ltr | Continuous fire watch |
| ML20045D720 | 22 June 1993 | LER 93-009-00:on 930524,apparent Spurious Signal from Pressurizer Level Instrumentation Caused Backup Charging Pumps to Automatically Start,Due to Deterioration of Wiring. Instrument Loop Calibration Will Be performed.W/930622 Ltr | Boric Acid |
| ML20045D374 | 21 June 1993 | LER 93-008-00:on 930520,determined That TS SR Not Satisfied for Stack Flow Indicator,Per Amend 137 Issued on 910307. Caused by Lack of Attention to Detail.Calibr & Functional Test Procedures developed.W/930621 Ltr | |
| ML20044H526 | 1 June 1993 | LER 93-007-00:on 930430,unplanned Emergency Generator Start & Rt Signal Occurred.Caused by Inadequate Attention to Detail,Labeling of Fuse Drawers,Caution Signs & Training. Labeling & Caution Signs upgraded.W/930601 Ltr | Safe Shutdown |
| ML20044G494 | 26 May 1993 | LER 93-006-00:on 930118,Halon Fire Suppression Sys for Switchgear Rooms Disabled to Allow Repair/Replacement of Halon Sys Piping.On 930427,individual Responsible for Fire Watch Not Present.Individual Relieved of Responsibilities | Continuous fire watch Fire Watch |
| ML20044B671 | 22 February 1993 | LER 93-002-00:on 930122,determined That Current SG LP Signal Block Reset Values Greater than Allowed Ts.Caused by Improper Design.Test Procedures Will Be Revised by 930917 to Specify Desired Value for Block function.W/930222 Ltr | Time of Discovery |
| ML20024G682 | 19 April 1991 | LER 91-007-00:on 910320,480 Volt Circuit Breaker Coordination Outside Design Basis.Caused by Deficiencies in Original Sys Design.Breaker/Fuse Coordination Study to Be Completed & Problems Will Be corrected.W/910419 Ltr | Safe Shutdown |
| ML20029C159 | 21 March 1991 | LER 91-004-00:on 910212,offsite Power Low Signal Outside Design Basis.Caused by Inadequate Mod Design at Time of Performance of Original Degraded Voltage Analysis. Engineering Analysis EA-FC-91-017 performed.W/910321 Ltr | |
| ML20029C105 | 18 March 1991 | LER 91-002-00:on 901209,ventilation Isolation Actuation Signal Generated by High Alarm on Process Radiation Monitor RM-062.Caused by Accumulation of Noncondensible Gases in Sample Piping.Valve Packing Leak repaired.W/910318 Ltr | Packing leak |
| ML20029A298 | 8 February 1991 | LER 91-001-00:on 910109,determined That Containment Tendon Surveillances Performed in 1981 & 1985 Did Not Reflect Guidance in Tech Specs.Caused by Inadequate Administrative Controls.Testing Program Plan implemented.W/910208 Ltr | |
| ML20029A297 | 6 February 1991 | LER 90-022-02:on 900907,approx 460 Fire Barrier Penetration seals,60 Fire Dampers & 6 Fire Doors Declared Nonfunctional Per NRC Info Notice 88-004 Due to Lack of Documentation. Plant Outage Required to Implement Repairs/Replacements | Safe Shutdown Fire Barrier |
| ML20028G917 | 28 September 1990 | LER 90-021-00:on 900829,inadvertent Reactor Protective Sys Actuation Occurred While Operator Changed Power Source. Caused by Operator Not Following Proper Procedures.Operator counseled.W/900928 Ltr | |
| ML20044B013 | 12 July 1990 | LER 90-018-00:on 900612,reactor Protective Sys (RPS) Trip Units for Axial Power Distribution Determined to Be Inoperable.Caused by Procedural Deficiencies.Procedure Revised & RPS Surveillance Tests reviewed.W/900712 Ltr | |
| ML20043F630 | 11 June 1990 | LER 90-016-00:on 900511,accident Scenarios Identified by Which Auxiliary Feedwater Piping from Discharge of Turbine Driven Auxiliary Feedwater Pump FW-10 Can Be Overpressurized.Caused by Design deficiency.W/900611 Ltr | Unanalyzed Condition |
| ML20043F244 | 7 June 1990 | LER 90-015-00:on 900507,PORV Variable Setpoints Used for Low Pressure Overpressure Protection Determined to Be Nonconservative for PORV Opening Time.Caused by Design Deficiency.Tech Spec Amend prepared.W/900607 Ltr | Stroke time |
| ML20043C099 | 29 May 1990 | LER 90-014-00:on 900427,investigation Revealed That Component Cooling Water Piping to Reactor Coolant Pump Seal Coolers Could Be Targets of High Energy Line Break.Safety Analysis for Operability completed.W/900529 Ltr | |
| ML20042G721 | 10 May 1990 | LER 90-011-00:on 900402,inadvertent Actuation of Pressurizer Pressure Low Signal Occurred While Performing Calibr Procedure.Caused by Inappropriate Action by Technician Involved.Validation of Procedures reviewed.W/900510 Ltr | |
| ML20042E687 | 23 April 1990 | LER 90-007-01:on 900228,determined That Several Supports Would Be Overloaded During Seismic Event on Nonsafety Related & safety-related Main Steam Piping.Caused by Design Deficiency.Piping Supports modified.W/900423 Ltr | Temporary Modification Design basis earthquake Earthquake |
| ML20042E686 | 23 April 1990 | LER 90-009-00:on 900316,potential Overpressurization of Auxiliary Feedwater Piping Could Have Occurred During Thermal Expansion of Process Fluid Between Closed Valved. Caused by Design deficiencies.W/900423 Ltr | |
| ML20012E764 | 26 March 1990 | LER 90-005-00:on 900223,determined That Spent Fuel Pool Area Charcoal Filtration Unit VA-66 Was Outside Design Basis. Caused by Insufficient Airflow Into Unit.Affected Updated SAR Analysis Will Be updated.W/900326 Ltr | Unanalyzed Condition |
| ML20012D012 | 19 March 1990 | LER 90-004-00:on 900217,lift Pressures for 6 of 10 Main Steam Safety Valves Found Outside Acceptance Criteria. Caused by Overly Restrictive Operability Criteria.Valves Recalibr & License Amend Submitted to NRC.W/900319 Ltr | Time of Discovery |
| ML20012D010 | 19 March 1990 | LER 90-003-00:on 900216,determined That Auxiliary Feedwater Piping Outside Normal Stress Limits of ASME Code & Design Basis Specified in Updated Sar.Caused by Design Deficiency.Valve Operators Will Be inspected.W/900319 Ltr | Non-Destructive Examination Nondestructive Examination |
| ML20012B636 | 9 March 1990 | LER 89-017-01:on 890624,internal Valve Component from Check Valve Found Lying on Pump Discharge Vane.Repair or Replacement of Valve Internals Could Not Be Accomplished within Time Requirement of Tech Spec.W/900309 Ltr | Temporary Modification |
| ML20006E104 | 9 February 1990 | LER 90-001-00:on 900108,fire Barrier for Wall Between Auxiliary Bldg Rooms 26 & 34 Breached But Hourly Fire Watch Patrol Not Established.Caused by Lack of Sufficient Training for Shift Supervisors.Standing Order revised.W/900209 Ltr | Fire Barrier Fire Protection Program Fire Watch Hourly Fire Watch |
| ML20011E269 | 5 February 1990 | LER 89-024-00:on 891221,determined That Containment Spray Pumps & Suction Header Piping Not Constructed for Use as Backup to LPSI Sys for Shutdown Cooling.Caused by Inadequate Review of Assumptions.Firewatch established.W/900205 Ltr | Hydrostatic Exemption Request |
| ML20011E227 | 1 February 1990 | LER 89-021-00:on 891010,util Informed by C-E of Potential Nonconservative Setpoint in Reactor Protection Sys Thermal Margin/Low Pressure Trip Unit.Caused by Error in Incorporating Transient Setpoint analyses.W/900201 Ltr | |
| ML20005F715 | 10 January 1990 | LER 89-023-00:on 891211,hourly Firewatch Patrol Entered Posted High Radiation Area W/O Meeting Entry Requirements for Area.Briefings on High Radiation Entry Requirements Held for Personnel W/Assigned dosimetry.W/900110 Ltr | High Radiation Area |
| ML19354D638 | 20 December 1989 | LER 89-022-00:on 890805,change to Surveillance Procedure ST-CEA-1 Became Effective Which Would Have Made Both Emergency Diesel Generators Simultaneously Inoperable During Portion of Test.Change removed.W/891220 Ltr | |
| ML19332E743 | 8 December 1989 | LER 88-037-01:on 881214,one of Two Supply Headers Supplying Fire Suppression Headers in Auxiliary Bldg Isolated.Caused by Lack of Procedural Guidance & Inadequate Procedural Controls.Standing Order G-58 Will Be revised.W/891208 Ltr | Continuous fire watch Hourly Fire Watch |
| ML19332E268 | 1 December 1989 | LER 89-016-02:on 890616,for Unknown Period Since 890614, Auxiliary Feedwater Pump FW-10 Operated Outside Design Basis for Certain Accident Conditions.Caused by Inoperable Speed Control Loop.Action Plan implemented.W/891201 Ltr | |
| ML19351A454 | 22 November 1989 | LER 89-020-00:on 891012,determined That Two of Four Component Cooling Water HXs Simultaneously Inoperable for More than 24 H.Caused by Inadequate Controls Re Return of Equipment to Svc.Standing Order revised.W/891122 Ltr | Safe Shutdown Ultimate heat sink |
| ML19327B548 | 24 October 1989 | LER 89-019-00:on 890924,indication of High Temp for Reactor Coolant Pump RC-3A Upper Motor Thrust Bearing Received in Control Room.Caused by Damaged Cable for Bearing Resistive Temp Device.Damaged Cable replaced.W/891024 Ltr | |
| ML19325D247 | 13 October 1989 | LER 89-012-01:on 890502,main Feedwater Isolation Valve to Steam Generator a Found Inoperable Due to Improperly Set Torque Switch.Caused by Inadequate Program for Maint of Motor Operated Valves.Torque Switches reset.W/891013 Ltr | |
| ML20028C771 | 6 January 1983 | LER 82-020/03L-0:on 821207,during Main Steam Safety Valve Test,Four Main Steam Safety Valves Had Lift Setpoints Out of Tolerance.Caused by Normal Drift of Valves Over Operating Cycle.Valves Readjusted | |
| ML20028B545 | 28 October 1982 | LER 82-019/03L-0:on 821024,MSIVs HCV-1041A & HCV-1042A Stopped Three to Four Degrees Off Seat When Signaled to Close.Caused by Binding Between Valve Packing & Shaft. Packings Sprayed W/Penetrant Oil | |
| ML20052J063 | 27 April 1982 | LER 82-009/03L-0:on 820411,while Exchanging Component Cooling Water Heat Exchangers,Associated Outlet Valves HCV-490B,HCV-491B & HCV-492B Failed to Open.Cause Not stated.HCV-491B Reassembled & Tested | Time of Discovery |
| ML20052B236 | 7 April 1982 | LER 82-006/03L-0:on 820323,during Surveillance Test ST-ISI- WD-1,F.1,valve HCV-506A Failed to Close Via Control Room Switch.Caused by Solenoid Valve Malfunction.Solenoid Valve Disassembled,Cleaned & Reassembled | Safe Shutdown |
| ML20052D929 | 6 April 1982 | LER 82-008/03L-0:on 820330,during Performance of ST-FW-1, F.2(b)(6)per Tech Spec 3.9,steam Driven Auxiliary Feedwater Pump Failed to Start.Caused by Back Pressure Trip Lever in Tripped Position.Lever Reset | |
| ML20041G129 | 22 February 1982 | LER 82-005/03L-0:on 820210,at 98% Power,Control Element 24 Inserted Into Core.Emergency Procedure EP-13,CEDM Malfunctions,Implemented & Power Stabilized at 88%.Caused by Erroneous Operating Instruction.Instruction Changed | Boric Acid |
| ML20041F748 | 17 February 1982 | LER 82-003/03L-0:on 820203,containment Isolation Valve Associated W/Gas Vent Header HCV-507A Failed to Close on Demand.Caused by Solenoid Valve Plunger Sticking in Energized Position.Plunger Freed | Safe Shutdown |
| ML20041F625 | 5 February 1982 | LER 82-004/03L-0:on 820203,small Quantity of Radioactive Gas/Particulate Released to Auxiliary Bldg During Routine Operation.Caused by Failure of Stack Gas Monitor RM-062 to Alarm at Appropriate Setpoint Due to Faulty Alarm Module | |
| ML20041B105 | 28 January 1982 | LER 82-002/03L-0:on 820114,at 99% Power,Lockout Relay 86B1, Containment Radiation High Signal,Failed to Actuate on Demand by Plant Radiation Monitoring Sys.Caused by Burnt Coil on Lockout Relay.Coil Replaced & Tested Satisfactorily | |
| ML20041B117 | 19 January 1982 | LER 82-001/03L-0:on 820111,during Normal Operation,Two Fire Barrier Penetrations Found Nonfunctional.Shift Supervisor Immediately Notified;However,Fire Watch Not Posted.Insp & Supervisor Personnel Instructed on Proper Actions | Fire Barrier Fire Watch Hourly Fire Watch |
| ML20039B456 | 11 December 1981 | LER 81-011/03L-0:on 811113,containment Isolation Valves Opened & Ventilation Process Initiated W/Containment Air Monitor RM-050/051 Inoperable.Caused by Personnel Error. Valves Closed | |
| ML20010H858 | 27 August 1981 | LER 81-008/03L-0:on 810813,86B/CRHS (Containment Radiation High Signal) Lockout Relay Failed to Actuate When RM-062 Was Placed in Alarm,Resulting in Failure of 86B1/CRHS Relay to Actuate.Caused by Dirt in Relay Latching Mechanism | |
| ML20041F629 | 27 August 1981 | LER 81-008/03L-1:on 810813,containment Radiation High Signal 86B Lockout Relay Failed to Actuate When Radiation Monitor RM-062 Placed in Alarm.Caused by Bound Relay Latching Mechanism Due to Dirt & Grease.Latch Cleaned | |
| ML20010C227 | 7 July 1981 | LER 81-006/03L-0:on 810624,reactor Protection Sys Nuclear Power Recorder Channel B Trip Setpoints Determined to Be Nonconservative.Caused by Faulty Temp Change Power Calculation Due to Grounded Hot Leg Temp Loop | |
| ML20004B111 | 6 May 1981 | LER 81-005/03L-0:on 810423,dc Sequencer Timers AC-3A (Component Cooling Water Pump) & AC-102A (Raw Water Pump) Failed to Time Out within Prescribed Limit.Cause Unknown Mechanisms Satisfactorily Inspected | Safe Shutdown |