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 Issue dateTitleTopic
ML17303B18230 December 1986LER 86-058-01:on 861111 & 18,overtemp Delta T Reactor Trip Occurred on Increasing Reactor Coolant Temp Rate.Caused by Spike on Potentiometer.Valve Realigned & Unit Returned to Previous status.W/861230 Ltr
ML19324B11420 October 1989LER 89-024-00:on 890920,safety Review Group Staff Member Identified Committed Fire Door S102A as Possibly Inadequate. Caused by Design Deficiency.Fire Watch Established & Door repaired.W/891019 LtrFire Barrier
Fire Watch
Hourly Fire Watch
ML19324B40920 October 1989LER 89-025-00:on 890922,13.8 Kv Auxiliary Switchgear Deenergized Resulting in Loss of Power to Condenser Circulating Water Cooling Tower Fans.Power Reduction Due to Hurricane Hugo.W/891019 LtrHigh winds
Earthquake
Power change
ML19325C1964 October 1989LER 89-026-00:on 890823,tested Breaker Replaced W/Traceable Breaker in Response to Bulletin 88-010.Breaker Tripped. Caused by Mfg Deficiency.Work Request Written.Item Reportable Per Part 21.W/891003 LtrPast operability
Operability Determination
ML19325C63811 October 1989LER 89-023-00:on 890915,Tech Spec 3.0.3 Entered Due to Both Trains of Control Room Area Ventilation Sys Being Inoperable.Caused by Defective pre-operational Testing Procedure.Train a Control Room Damper adjusted.W/891011 LtrFire Watch
ML19325C64011 October 1989LER 89-016-00:on 890913,four Channels of Power Range Instrumentation Showed Greater than 5% Allowable Mismatch Between Rated Thermal Power & Nuclear Power.Caused by Equipment Failure.Pneumatic Gauge replaced.W/891011 Ltr
ML19325C64411 October 1989LER 89-019-00:on 890912,capability of Switches 2CA-15A & 2CA-18B Disabled Rendering Feedwater Pumps 2A & 2B Inoperable.Caused by Defective Procedure & Inappropriate Actions.Procedure Revised & Update issued.W/891011 Ltr
ML19327B60720 September 1989LER 89-025-00:on 890922,auxiliary Switchgear Deenergized, Resulting in Loss of Power to Condenser Circulating Water Cooling Tower Fans.Caused by Inoperable power-range Instrumentation Due to Hurricane Hugo.W/890920 LtrHigh winds
Earthquake
Power change
ML19332E7206 December 1989LER 89-023-01:on 890915,Tech Spec 3.0.3 Entered as Result of Both Trains of Control Room Area Ventilation Sys Being Inoperable.Caused by Equipment Malfunctions.Control Room & Area Pressurization Flow Rates revised.W/891120 LtrFire Watch
ML19354D82615 January 1990LER 89-029-00:on 891213,determined That Max Actuator Torque Switch Setting Insufficient to Overcome Friction Force Due to Age Hardening of Elastomeric Seat Matl on Bif/General Signal Corp Valve.Also Reported Per Part 21.W/900112 LtrStroke time
Operability Determination
ML19354E01919 January 1990LER 89-020-01:on 891118,Tech Spec 3.0.3 Entered & 5-month Auxiliary Bldg Ventilation Sys Inoperability Occurred as Result of Low Filter Exhaust Flow Condition on 891111.Caused by Design Oversight.Duct Will Be cleaned.W/900119 LtrTime of Discovery
Past operability
ML19354E02018 January 1990LER 89-016-01:on 890913,generator 1B Power Circuit Breaker Opened,Causing Unit Runback to 54% Power & Failure of Generator Breaker Air Pressure Gauge.Caused by Equipment Failure.Pneumatic Gauge replaced.W/900117 Ltr
ML19354E09318 January 1990LER 89-025-01:on 890922,power Lost to Condenser Circulating Water Cooling Tower Fans Due to Deenergization of 13.8 Kv Auxiliary Switchgear.Caused by Weather Conditions.Reactor Power Reduced to Maintain Condenser vacuum.W/900119 LtrHigh winds
Earthquake
Power change
ML20005E40229 December 1989LER 89-028-00:on 891204,steam Generator 1D Power Operated Relief Valve Did Not Close on Train a Main Steam Isolation Signal During Valve Inservice Test.Caused by Failed Fuse. Fuse replaced.W/891229 LtrStroke time
ML20005G3069 January 1990LER 89-020-00:on 890921,abnormal Degradation of Steel Containment Vessels Observed.Caused by Corrosion by Standing Water in Annulus Areas.Steel Containment Vessels Will Be Recoated During Next Refueling outage.W/900109 LtrBoric Acid
Overexposure
ML20005G42612 January 1990LER 89-013-00:on 890726,two Carbon Steel Liners,Containing Mixture of Powdex & Bead Resins,Shipped to Barnwell,Sc,In Violation of Process Control Program.Caused by Mgt Deficiency.Shipment suspended.W/900112 LtrProcess Control Program
ML20006D4867 February 1990LER 90-001-00:on 900105,unexpected Auxiliary Feedwater Automatic Startup Occurred During Periodic Cabinet Test. Caused by Procedure Deficiency.Procedures to Be Revised to Prevent recurrence.W/900207 Ltr
ML20006E82314 February 1990LER 90-004-00:on 900104,contact Carrier Screws in nonsafety- Related Breaker Found Loose & in Bottom of Motor Control Ctr Cubicle.Caused by Mfg Deficiency.Loose Screws Secured. Part 21 related.W/900215 LtrSafe Shutdown
Past operability
Operability Determination
Loctite
ML20011D23218 December 1989LER 89-020-00:on 891111,low Filtered Exhaust Flow Discovered by Control Room Operators During Observation of Indications. Caused by Design Oversight Re Interaction of Sys/Components. Clothes Dryer Filters to Be modified.W/891218 LtrTime of Discovery
Past operability
ML20011D33220 December 1989LER 89-021-00:on 890821,hydrogen Skimmer Fan 2A Declared Inoperable in Order to Replace Breaker,In Response to NRC Bulletin 88-010.On 890825,breaker Tripped & Power Reduction Resumed.Caused by Inappropriate action.W/891222 LtrFuel cladding
Power change
ML20011D33520 December 1989LER 89-027-00:on 891120,chemical & Vol Control Sys Centrifugal Charging Pump 1B Declared Inoperable Due to Inability to Maintain Sufficient Charging Flow.Cause Not determined.Power-range Detector replaced.W/891222 Ltr
ML20011E2282 February 1990LER 90-002-00:on 900103,containment Air Return Fan 1B Failed to Start During Quarterly Test & Breaker F01A in Motor Control Ctr Discovered Open.Caused by Inappropriate Operator Action.Lockout Breakers closed.W/900202 Ltr
ML20011E3952 February 1990LER 90-001-00:on 891116,potential Concern Identified W/ Pressurizer Safety Valve Blowdown Being Greater than Assumed in Safety Analyses.Caused by Functional Design Deficiency. Also Reportable Per Part 21.W/900202 LtrLoop seal
ML20012A17827 February 1990LER 90-005-00:on 900126,Tech Spec 3.0.3 Entered Due to Inoperable Power Range Nuclear Instrumentation (Prni) During Unit Shutdown.Caused by Mgt Deficiency.Action Developed to Better Anticipate & Carry Out Prni calibr.W/900227 LtrPower change
ML20012B8129 March 1990LER 90-008-00:on 900203,discovered That Insulation Removed from Main Steam Auxiliary Equipment Piping to Auxiliary Feedwater Pump Turbine.Caused by Design Oversight Due to Unanticipated Interaction of sys.W/900309 LtrFire Barrier
Fire impairment
Continuous fire watch
Fire Watch
ML20012C37413 March 1990LER 90-012-00:on 900127,central Alarm Station Operator Noted That Controlled Access Door Not Closed.Caused by Inappropriate Action Taken Which Was Unauthorized.Personnel Counseled on Importance of Sys operability.W/900313 LtrHigh Radiation Area
Fire Barrier
Operability Determination
Continuous fire watch
Fire Watch
Hourly Fire Watch
ML20012C4967 March 1990LER 90-010-00:on 900205,discovered That Standby Shutdown Facility Wide Range RCS Temp Indications Had Not Been Subj to Monthly Channel Check as Required by Tech Spec 4.7.13.6. Caused by Defective procedure.W/900307 LtrTime of Discovery
Fire Protection Program
ML20012C50913 March 1990LER 90-009-00:on 900212,containment Purge Sys Heaters Not Being Verified to Be Running During Monthly Surveillance as Required by Tech Specs.Caused by Defective Procedures,Due to Incomplete Info.Procedures revised.W/900313 Ltr
ML20012C51112 March 1990LER 90-007-01:on 891108,discovered That Transmission Procedures Used to Perform Undervoltage Relay Tests Revealed That Test Acceptance Criteria Did Not Agree W/Tech Specs & Relays Not Being Adjusted as required.W/900316 Ltr
ML20012C68815 March 1990LER 90-011-00:on 900215,discovered That Control Room Doors Were More Difficult to Open than Normal.Ventilation Sys Found to Be Incapable of Maintaining Positive Pressure. Caused by Design Deficiency.Walls sealed.W/900315 LtrOperability Determination
ML20012C69015 March 1990LER 90-005-01:on 900126,Tech Spec 3.0,3 Entered Due to More than One Power Range Nuclear Instrumentation Channel Exceeding 5% Deviation.Caused by Mgt Deficiency.Operations Procedure revised.W/900314 LtrPower change
ML20024G73718 April 1991LER 91-006-00:on 910323,nuclear Svc Water Valves Left W/O Emergency Power Supply.Caused by Inappropriate Action Due to Misreading of Operator Aid Computer (Oac) Graphics.Oac Graphics Training Will Be provided.W/910418 LtrDesign basis earthquake
Earthquake
ML20024G9759 May 1991LER 91-004-00:on 910410,tech Spec Violation Occurred Re Containment Valve Injection Water Sys Being Inoperable. Caused by Inapropriate Action.Maint Staff Instructed Supervisors & Technicians of Correcting cause.W/910509 Ltr
ML20024J2604 October 1994LER 94-006-00:on 940913,automatic Reactor/Turbine Trip Occurred on Over Power Differential Temperature.Caused by Equipment Failure.Replaced Relay & Evaluated Failure Rate of Types of relays.W/941004 LtrSafe Shutdown
Thermography
ML20029A33112 February 1991LER 91-002-00:on 910113,reactor Exceeded 5% Power Level W/ RHR Sys Pump 1A Inoperable Due to Closed Suction Valve. Caused by Inappropriate Action & Procedural Deficiency. Incident Discussed W/Involved personnel.W/910212 Ltr
ML20029D10120 April 1994LER 93-003-01:on 930925,reactor Tripped Due to Inadvertent Closure of Msiv.Caused by Inadequate Checking.Corrective Actions:Cros Throttled CA Flow & Entered Procedure EP/2/A/5000/01.W/940420 LtrSafe Shutdown
ML20042E3143 April 1990LER 90-002-01:on 900103,containment Air Return Fan Failed to Start During Test & Breaker FO1A in Motor Control Ctr Opened.Caused by Inappropriate Action.Measures Taken to Ensure Positions of Breakers verified.W/900409 Ltr
ML20042F4723 May 1990LER 90-015-00:on 900402,Tech Spec 3.0.3 Entered When Both Trains of Containment Valve Injection Water Sys Rendered Inoperable.Caused by Supervisor Incorrectly Denoting Valve Position.Valves 1RN-493 & 494 closed.W/900430 Ltr
ML20042F4743 May 1990LER 90-006-00:on 900321,discovered That Nuclear Svc Water Sys Assured Makeup Source to Containment Valve Injection Water Sys Surge Chamber 2A Would Not Provide Adequate Flow. Caused by Clogged pipe.W/900430 Ltr
ML20042G6309 May 1990LER 90-025-00:on 900409,unexpected ESFs Actuation Occurred During Performance of Incore Thermocouple Testing.Caused by Deficient Procedure.Procedure Revised & Reviewed W/Personnel Lessons Learned from event.W/900503 Ltr
ML20043A9273 May 1990LER 89-030-01:on 890726,Tech Spec Violation Occurred Due to Shipment of Two Liners of Secondary Bead & Powdex Resin Mixture.On 891215,same Tech Spec Violation Occurred.Caused by Mgt Deficiency.Shipments suspended.W/900503 LtrProcess Control Program
ML20043C89529 May 1990LER 89-010-01:on 880314,auxiliary Feedwater Pump 2A Discharge to Steam Generator 2A Isolation Failed to Completely Close.Caused by Design Deficiency.Mods to Actuator Torque Switch Setting increased.W/900524 Ltr
ML20043G64414 June 1990LER 90-008-00:on 900430,high Pressure CO2 Discharge Occurred on Auxiliary Feedwater Fire Protection Sys.Caused by Const/ Installation Deficiency in Solenoids.Solenoids Orientation Verified to Be Installed correctly.W/900614 LtrSafe Shutdown
Fire Barrier
Past operability
Continuous fire watch
Hourly Fire Watch
ML20044B17610 July 1990LER 90-013-00:on 900611,approx 5,000 Gallons of RCS Water Inadvertently Transferred to Refueling Water Storage Tank. Caused by Inappropriate Action.Proper Sys Parameters Restored & Analysis of Event performed.W/900709 Ltr
ML20045H24212 July 1993LER 93-006-00:on 930612,automatic Reactor Trip Initiated by intermediate-range Channel N35 Hi Flux Reactor Trip Bistable.Caused by Blown Fuse in Channel.Entire Drawer Replaced & Channel Placed Back in svc.W/930712 LtrSafe Shutdown
ML20046D58717 August 1993LER 93-008-00:on 930718,reactor Tripped & Auxiliary Feedwater Sys Automatic Start Due to low-low-level in SG 1A. Developed General Troubleshooting procedure.W/930817 Ltr
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