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Category:LICENSEE EVENT REPORT (SEE ALSO AO
MONTHYEARML20029D0261994-04-22022 April 1994 LER 94-002-00:on 940329,inadvertent Automatic Closure of Primary Containment Isolation Valves & ESF Actuations Occurred Due to Malfunctioning Handswitch.Caused by Weak Electrical Contact Spring.Handswitch replaced.W/940422 Ltr ML20046B4961993-07-30030 July 1993 LER 93-008-00:on 930627,MCR Annunciator Alarmed Indicating That Outside Atmosphere Reactor Encl (Re) Negative Differential Pressure Decayed Due to Failure of Normal Re Ventilation Fan Motor.Subj Fan replaced.W/930730 Ltr ML20046C3961993-07-30030 July 1993 LER 92-011-01:on 920605,discovered Potential Physical Electrical Separation Deficiency in Panel 10C790.Plant Electrical Maint I&C Technicians Received Training on Electrical Separation Requirements ML20046B5051993-07-30030 July 1993 LER 91-015-01:on 910912,HPCI Sys Discovered to Be in Degraded Condition When HPCI Turbine Steam Supply Valve Failed to Fully Open.Recommendations of EPRI Improved MOV Lubricant Program implemented.W/930730 Ltr ML20046B5001993-07-30030 July 1993 LER 93-008-00:on 930630,determined That TS SR on Fire Rated Assemblies Not Satisfied Due to Personnel Error During Procedure Preparation.Surveillance Test Procedure ST-7-022-922-0 Will Be revised.W/930730 Ltr ML20046A4431993-07-19019 July 1993 LER 93-007-00:on 930617,alarm Indicated TIP Sys Shear Valve Was Inoperable.Cause Interminate.Isolated Occurrence. W/930719 Ltr ML20045D3931993-06-21021 June 1993 LER 93-007-00:on 930521,primary Containment Isolation Valve Inoperable & TS Action Statement & SR Not Implemented in Required Time.Caused by Personnel Error.Ltr Issued to Personnel Emphasizing Requirement ML20044E7431993-05-20020 May 1993 LER 93-002-01:on 930124,discovered That EDG Inoperable Since 930119 Due to Improperly Connected Wires in Circuit Breaker. Wires Restored to Proper Position & Tested Satisfactorily. Procedural & Training Changes Also Implemented ML20044D1761993-05-0707 May 1993 LER 87-028-01:on 870610,hourly Fire Watch Required by TS 3.7.7 Not Performed Due to Personnel Error.Plant Security Organization Accepted Responsibility for Hourly Firewatch Patrol Required by Ts,Effective 930104 ML20044C9231993-05-0505 May 1993 LER 93-004-00:on 930405,primary Containment & Reactor Vessel Isolation Control Sys Actuation Occurred During Test of NSSSS-refueling Area Ventilation Exhaust Duct.Caused by Personnel Error.Technician counseled.W/930505 Ltr ML20024H0901991-05-10010 May 1991 LER 91-007-00:on 910410,handling of Control Rod Prohibited by Tech Spec Surveillance Requirements 4.9.6.3b.Caused by Inadequate Procedure.Maint Procedure Changed Deleting Provisions to Reposition Mechanical stop.W/910510 Ltr ML20024G6981991-04-22022 April 1991 LER 91-003-00:on 910324,inadvertent Actuation of Reactor Protection Sys Occurred.Caused by Personnel Error.Procedural Guidance Developed,Shift Training Bulletin Issued & Operator Requalification Training Module revised.W/910422 Ltr ML20029A8251991-02-27027 February 1991 LER 91-005-00:on 910130,pressure Differential Switch Restored Incorrectly,Causing Spurious Drywell Pressure Signal & ESF Actuation.Caused by Personnel Error.Personnel Counseled & Warning Labels added.W/910227 Ltr ML20029A7101991-02-22022 February 1991 LER 91-004-00:on 910123,determined That TS Section 3.3.7.5 Surveillance Requirements Not Satisfied for Fuel Zone Level & Neutron Flux Instrumentation.Caused by Misinterpretation of Ts.Calibr Procedures revised.W/910222 Ltr ML20028H7121991-01-22022 January 1991 LER 90-035-00:on 901224,14 Valves Associated W/Various Sys & Required to Perform Function of Isolating Primary Containment Determined Inoperable.Caused by Installation Error During Initial const.W/910122 Ltr ML20028H6791991-01-18018 January 1991 LER 91-002-00:on 910109,replacement Cassette Drive Unit to Replace Inoperable Seismic Monitoring Sys Not Received by 910109,rendering Sys Inoperable for More than 30 Days.Caused by Grit on Gear.Sys repaired.W/910118 Ltr ML20024F7361990-12-0707 December 1990 LER 90-025-00:on 901110,spurious LOCA Signal Resulted in ESF actuations.W/901207 Ltr ML20028G9221990-09-26026 September 1990 LER 90-017-00:on 900828,ESF Actuation of Primary Containment & Reactor Vessel Isolation Control Sys Occurred.Caused by Technician Inadvertently Shorting Power Supply During Installation of Test Jack.Blown Fuse replaced.W/900926 Ltr ML20044A9761990-07-12012 July 1990 LER 90-013-00:on 900611,dc Distribution Sys Identified to Have Inadequate Isolation Capability Between Class IE & non-Class IE Components.Cause of Event Under Investigation. Hourly Fire Watches Established Until 900626.W/900712 Ltr ML20043C5231990-06-0101 June 1990 LER 90-003-01:on 900208,HPCI Sys Isolation Valve Inadvertently Isolated During Surveillance Test.Caused by Both Channels of Isolation Logic Being in Tripped Condition at Same Time.Isolation of HPCI Sys reset.W/900601 Ltr ML20043C3211990-05-30030 May 1990 LER 90-012-00:on 900426,inoperability of RHR Sys Modes Occurred Due to Physical Separation Deficiencies.Caused by Drawing Deficiency Resulting in Installation Error During Original Const.Nonclass 1E Cable sleeved.W/900530 Ltr ML20043B1331990-05-21021 May 1990 LER 90-011-00:on 900420,discovered That Emergency Svc Water Pump B Discharge Check Valve Not Preventing Reverse Flow. Caused by Personnel Error in That Actuating Arm Incorrectly Assembled.Actuating Arm repositioned.W/900521 Ltr ML20043B1311990-05-18018 May 1990 LER 90-006-01:on 900223,determined That Capability to Activate Emergency Public Notification Sys Sirens from Counties Lost from 900112-0205.Caused by Disconnection of Phone Lines.Lines Reconnected for All counties.W/900518 Ltr ML20043A7651990-05-17017 May 1990 LER 90-008-00:on 900417,HPCI Sys Isolation & Inoperability Occurred Due to Failure of Differential Pressure Transmitter.Cause of Transmittal Failure Under Investigation.Transmitter Returned to mfg.W/900517 Ltr ML20043A6321990-05-15015 May 1990 LER 89-060-01:on 891212,standby Gas Treatment Sys Charcoal Filter Discovered in Degraded Condition W/Possible Bypass Leakage Paths.Similar Condition Discovered on 891218.Caused by Holes in Charcoal Filter assemblies.W/900515 Ltr ML20043A4261990-05-15015 May 1990 LER 90-010-00:on 900415,ESF Actuation Occurred Closing Three Containment Isolation Valves for Analyzers.Cause Unknown. Isolation Reset,Analyzers Returned to Svc & Voltmeter Not Being Used Pending Determination of cause.W/900515 Ltr ML20042G0521990-05-0404 May 1990 LER 90-009-00:on 900405,control Room Chlorine Isolation of Habitability Control Room Isolation Sys & ESF Initiated. Caused by Failure of B Toxic Gas Detector & False Signal from Untested Analyzer.Detector replaced.W/900504 Ltr ML20012C9361990-03-12012 March 1990 LER 90-005-00:on 900211,no Fire Watch Insps for Rooms 103, 114 & 117 on Elevation 177 Ft in Reactor Encl Performed by Personnel.Caused by Personnel Error.Person Involved Disciplined.Training Program improved.W/900312 Ltr ML20012C5541990-03-12012 March 1990 LER 90-004-00:on 900209,station Personnel Discovered That on 890708,22-s Reactor Power Transient Occurred in Which Reactor Thermal Power Changed by More than 15% of Rated Thermal Power in 1 H.Procedure revised.W/900312 Ltr ML20012C7071990-03-12012 March 1990 LER 90-003-00:on 900208,HPCI Sys Inboard Isolation Valve Inadvertently Isolated & Closed When One Channel of Isolation Logic Tripped.Caused by Degradation of Darlington Output Transistor.Isolation reset.W/900312 Ltr ML20011F7911990-02-26026 February 1990 LER 90-002-00:on 900125,identified That Main Control Room Ventilation Sys Outside Design Basis.Caused by Misapplication of Design Basis Assumptions.No Immediate Actions Taken as Existing Procedures adequate.W/900226 Ltr ML20006E4271990-02-0909 February 1990 LER 90-001-00:on 900122,discovered That Monthly Instrument Channel Functional Test for RCIC Steam Supply Pressure Low Missed.Caused by Deficiency in Computer Program Used to Schedule Tests.Computer Program revised.W/900209 Ltr ML20006E3451990-02-0808 February 1990 LER 90-003-00:on 900112,primary Containment & Reactor Vessel Isolation Control Sys Isolation Signals Initiated, Closing Inboard & Outboard Isolation Valves for Rwcu.Caused by Lifting Relief Valve.Opening Time reset.W/900208 Ltr ML20006E2851990-02-0707 February 1990 LER 90-002-00:on 900105,containment H2/O2 Analyzer Declared Inoperable During Containment Inerting.Caused by Reversed Tubing Connections in Installation of Analyzer Due to Mislabeling.Analyzer restored.W/900207 Ltr ML20006D5171990-02-0707 February 1990 LER 90-001-00:on 900108,Tech Spec Violation & Reactor Encl Ventilation Isolation Occurred.Caused by Personnel Error. Chief Operator Counseled on Importance of Communicating All Pertinent info.W/900207 Ltr ML20006A8801990-01-19019 January 1990 LER 89-015-00:on 891223 & 24,problem W/Reactor Protection Sys (Rps)/Uninterruptable Power Supply Static Inverter Caused Loss of Power to RPS Panel.Caused by Failure of Gate Drive Boost Card.Isolations reset.W/900119 Ltr ML20005F9441990-01-10010 January 1990 LER 89-060-00:on 891212,standby Gas Treatment Sys Charcoal Filter a Discovered to Be Degraded W/Possible Bypass Leakage Paths.On 891218,filter B Found W/Similar Condition.Caused by Failure of Spot Welds.Filters repaired.W/900110 Ltr ML20005E6841990-01-0303 January 1990 LER 89-059-00:on 891206,instrumentation & Controls Technician Inadvertently Grounded Test Jack,Resulting in Blown Fuse.Caused by Personnel Error.Fuse Replaced. Technicians counseled.W/900103 Ltr ML20042D1961989-12-29029 December 1989 LER 89-009-02:on 890820 & 0925,RCIC Sys Injections Into RCS Occurred During Startup Test.From 891023-26,three HPCI Sys Injections Into RCS Occurred During Test.Injections Anticipated.Startup Tests performed.W/891229 Ltr ML20005E3301989-12-29029 December 1989 LER 89-014-00:on 891202,unexpected Actuation of Primary Containment & Reactor Vessel Isolation Control Sys Occurred. Caused by Insufficient Guidance in General Plant Procedure. Appropriate Procedures Reviewed & revised.W/891229 Ltr ML20005E0961989-12-26026 December 1989 LER 89-058-00:on 891123,actuation of Group III Primary Containment & Reactor Vessel Isolation Control Sys Resulted in Automatic Isolation of Rwcu.Caused by Failure of Flow Summer Card.Card replaced.W/891226 Ltr ML20011D2291989-12-19019 December 1989 LER 89-057-00:on 891120,refuel Floor Secondary Containment Isolated on Low Flow Differential Pressure,Causing Initiation of Standby Gas Treatment Sys.Caused by Severe Storm.Normal Ventilation Restored to floor.W/891219 Ltr ML19332F8631989-12-13013 December 1989 LER 89-056-00:on 891119,unexpected Nuclear Steam Supply Shutoff Sys Group Iii,Div 4 Isolation Initiated ESF Actuation.Caused by Defective read-set Selector Switch. Switch repositioned.W/891213 Ltr ML19332F7761989-12-11011 December 1989 LER 89-013-00:on 891110,reactor Scram Occurred Following Main Turbine Trip,Causing Initiation Signals on HPCI & RCIC Sys Due to Spiking of Level Transformers.Caused by Design Error.Hpci Turbine secured.W/891211 Ltr ML19332F7751989-12-11011 December 1989 LER 89-012-00:on 891110,RWCU Sys Differential Flow Oscillations Observed While Placing RWCU 2A Filter/ Demineralizer Into Svc.Caused by Leakage in Reactor HX Tube Side Safety Relief Valve.Valve removed.W/891211 Ltr ML19332F2961989-11-29029 November 1989 LER 89-009-01:on 890820,eight RCIC Sys Injections Into RCS Occurred Under Purview of Facility start-up Test Program. Caused by Abnormal Plant Conditions Requiring Safety Sys Actuations.Rcic & HPCI Sys Tests completed.W/891129 Ltr ML19332D6331989-11-27027 November 1989 LER 89-011-00:on 891027,outboard Nuclear Steam Supply Shutoff Sys Isolation Valves Isolated.Caused by Personnel Error Due to Lack of Attention to Detail by Technicians. Event Discussed at All Hands meeting.W/891127 Ltr ML19332D6251989-11-27027 November 1989 LER 89-055-00:on 891025,reactor Protection Sys 1A Shunt Trip Breaker Tripped on Undervoltage,Causing Loss of Power to Distribution Panel 1AY160 & ESF Isolation.Caused by Relief Valve Failures.Isolations reset.W/891127 Ltr ML19332C1781989-11-17017 November 1989 LER 89-053-00:on 891022,control Room Personnel Manually Initiated Ventilation Sys Chlorine Isolation,Esf.Caused by High Vinyl Chloride Concentration in Outside Air Intake Plenum.Special Event Procedure implemented.W/891117 Ltr ML19332B9841989-11-15015 November 1989 LER 89-054-01:on 891025,discovered That Daily Channel Check Surveillance Requirement for Channel D High Level Trip Not Met.Caused by Procedural Deficiency Since Initial Plant Operation.Associated Log Procedures revised.W/891115 Ltr 1994-04-22
[Table view] Category:RO)
MONTHYEARML20029D0261994-04-22022 April 1994 LER 94-002-00:on 940329,inadvertent Automatic Closure of Primary Containment Isolation Valves & ESF Actuations Occurred Due to Malfunctioning Handswitch.Caused by Weak Electrical Contact Spring.Handswitch replaced.W/940422 Ltr ML20046B4961993-07-30030 July 1993 LER 93-008-00:on 930627,MCR Annunciator Alarmed Indicating That Outside Atmosphere Reactor Encl (Re) Negative Differential Pressure Decayed Due to Failure of Normal Re Ventilation Fan Motor.Subj Fan replaced.W/930730 Ltr ML20046C3961993-07-30030 July 1993 LER 92-011-01:on 920605,discovered Potential Physical Electrical Separation Deficiency in Panel 10C790.Plant Electrical Maint I&C Technicians Received Training on Electrical Separation Requirements ML20046B5051993-07-30030 July 1993 LER 91-015-01:on 910912,HPCI Sys Discovered to Be in Degraded Condition When HPCI Turbine Steam Supply Valve Failed to Fully Open.Recommendations of EPRI Improved MOV Lubricant Program implemented.W/930730 Ltr ML20046B5001993-07-30030 July 1993 LER 93-008-00:on 930630,determined That TS SR on Fire Rated Assemblies Not Satisfied Due to Personnel Error During Procedure Preparation.Surveillance Test Procedure ST-7-022-922-0 Will Be revised.W/930730 Ltr ML20046A4431993-07-19019 July 1993 LER 93-007-00:on 930617,alarm Indicated TIP Sys Shear Valve Was Inoperable.Cause Interminate.Isolated Occurrence. W/930719 Ltr ML20045D3931993-06-21021 June 1993 LER 93-007-00:on 930521,primary Containment Isolation Valve Inoperable & TS Action Statement & SR Not Implemented in Required Time.Caused by Personnel Error.Ltr Issued to Personnel Emphasizing Requirement ML20044E7431993-05-20020 May 1993 LER 93-002-01:on 930124,discovered That EDG Inoperable Since 930119 Due to Improperly Connected Wires in Circuit Breaker. Wires Restored to Proper Position & Tested Satisfactorily. Procedural & Training Changes Also Implemented ML20044D1761993-05-0707 May 1993 LER 87-028-01:on 870610,hourly Fire Watch Required by TS 3.7.7 Not Performed Due to Personnel Error.Plant Security Organization Accepted Responsibility for Hourly Firewatch Patrol Required by Ts,Effective 930104 ML20044C9231993-05-0505 May 1993 LER 93-004-00:on 930405,primary Containment & Reactor Vessel Isolation Control Sys Actuation Occurred During Test of NSSSS-refueling Area Ventilation Exhaust Duct.Caused by Personnel Error.Technician counseled.W/930505 Ltr ML20024H0901991-05-10010 May 1991 LER 91-007-00:on 910410,handling of Control Rod Prohibited by Tech Spec Surveillance Requirements 4.9.6.3b.Caused by Inadequate Procedure.Maint Procedure Changed Deleting Provisions to Reposition Mechanical stop.W/910510 Ltr ML20024G6981991-04-22022 April 1991 LER 91-003-00:on 910324,inadvertent Actuation of Reactor Protection Sys Occurred.Caused by Personnel Error.Procedural Guidance Developed,Shift Training Bulletin Issued & Operator Requalification Training Module revised.W/910422 Ltr ML20029A8251991-02-27027 February 1991 LER 91-005-00:on 910130,pressure Differential Switch Restored Incorrectly,Causing Spurious Drywell Pressure Signal & ESF Actuation.Caused by Personnel Error.Personnel Counseled & Warning Labels added.W/910227 Ltr ML20029A7101991-02-22022 February 1991 LER 91-004-00:on 910123,determined That TS Section 3.3.7.5 Surveillance Requirements Not Satisfied for Fuel Zone Level & Neutron Flux Instrumentation.Caused by Misinterpretation of Ts.Calibr Procedures revised.W/910222 Ltr ML20028H7121991-01-22022 January 1991 LER 90-035-00:on 901224,14 Valves Associated W/Various Sys & Required to Perform Function of Isolating Primary Containment Determined Inoperable.Caused by Installation Error During Initial const.W/910122 Ltr ML20028H6791991-01-18018 January 1991 LER 91-002-00:on 910109,replacement Cassette Drive Unit to Replace Inoperable Seismic Monitoring Sys Not Received by 910109,rendering Sys Inoperable for More than 30 Days.Caused by Grit on Gear.Sys repaired.W/910118 Ltr ML20024F7361990-12-0707 December 1990 LER 90-025-00:on 901110,spurious LOCA Signal Resulted in ESF actuations.W/901207 Ltr ML20028G9221990-09-26026 September 1990 LER 90-017-00:on 900828,ESF Actuation of Primary Containment & Reactor Vessel Isolation Control Sys Occurred.Caused by Technician Inadvertently Shorting Power Supply During Installation of Test Jack.Blown Fuse replaced.W/900926 Ltr ML20044A9761990-07-12012 July 1990 LER 90-013-00:on 900611,dc Distribution Sys Identified to Have Inadequate Isolation Capability Between Class IE & non-Class IE Components.Cause of Event Under Investigation. Hourly Fire Watches Established Until 900626.W/900712 Ltr ML20043C5231990-06-0101 June 1990 LER 90-003-01:on 900208,HPCI Sys Isolation Valve Inadvertently Isolated During Surveillance Test.Caused by Both Channels of Isolation Logic Being in Tripped Condition at Same Time.Isolation of HPCI Sys reset.W/900601 Ltr ML20043C3211990-05-30030 May 1990 LER 90-012-00:on 900426,inoperability of RHR Sys Modes Occurred Due to Physical Separation Deficiencies.Caused by Drawing Deficiency Resulting in Installation Error During Original Const.Nonclass 1E Cable sleeved.W/900530 Ltr ML20043B1331990-05-21021 May 1990 LER 90-011-00:on 900420,discovered That Emergency Svc Water Pump B Discharge Check Valve Not Preventing Reverse Flow. Caused by Personnel Error in That Actuating Arm Incorrectly Assembled.Actuating Arm repositioned.W/900521 Ltr ML20043B1311990-05-18018 May 1990 LER 90-006-01:on 900223,determined That Capability to Activate Emergency Public Notification Sys Sirens from Counties Lost from 900112-0205.Caused by Disconnection of Phone Lines.Lines Reconnected for All counties.W/900518 Ltr ML20043A7651990-05-17017 May 1990 LER 90-008-00:on 900417,HPCI Sys Isolation & Inoperability Occurred Due to Failure of Differential Pressure Transmitter.Cause of Transmittal Failure Under Investigation.Transmitter Returned to mfg.W/900517 Ltr ML20043A6321990-05-15015 May 1990 LER 89-060-01:on 891212,standby Gas Treatment Sys Charcoal Filter Discovered in Degraded Condition W/Possible Bypass Leakage Paths.Similar Condition Discovered on 891218.Caused by Holes in Charcoal Filter assemblies.W/900515 Ltr ML20043A4261990-05-15015 May 1990 LER 90-010-00:on 900415,ESF Actuation Occurred Closing Three Containment Isolation Valves for Analyzers.Cause Unknown. Isolation Reset,Analyzers Returned to Svc & Voltmeter Not Being Used Pending Determination of cause.W/900515 Ltr ML20042G0521990-05-0404 May 1990 LER 90-009-00:on 900405,control Room Chlorine Isolation of Habitability Control Room Isolation Sys & ESF Initiated. Caused by Failure of B Toxic Gas Detector & False Signal from Untested Analyzer.Detector replaced.W/900504 Ltr ML20012C9361990-03-12012 March 1990 LER 90-005-00:on 900211,no Fire Watch Insps for Rooms 103, 114 & 117 on Elevation 177 Ft in Reactor Encl Performed by Personnel.Caused by Personnel Error.Person Involved Disciplined.Training Program improved.W/900312 Ltr ML20012C5541990-03-12012 March 1990 LER 90-004-00:on 900209,station Personnel Discovered That on 890708,22-s Reactor Power Transient Occurred in Which Reactor Thermal Power Changed by More than 15% of Rated Thermal Power in 1 H.Procedure revised.W/900312 Ltr ML20012C7071990-03-12012 March 1990 LER 90-003-00:on 900208,HPCI Sys Inboard Isolation Valve Inadvertently Isolated & Closed When One Channel of Isolation Logic Tripped.Caused by Degradation of Darlington Output Transistor.Isolation reset.W/900312 Ltr ML20011F7911990-02-26026 February 1990 LER 90-002-00:on 900125,identified That Main Control Room Ventilation Sys Outside Design Basis.Caused by Misapplication of Design Basis Assumptions.No Immediate Actions Taken as Existing Procedures adequate.W/900226 Ltr ML20006E4271990-02-0909 February 1990 LER 90-001-00:on 900122,discovered That Monthly Instrument Channel Functional Test for RCIC Steam Supply Pressure Low Missed.Caused by Deficiency in Computer Program Used to Schedule Tests.Computer Program revised.W/900209 Ltr ML20006E3451990-02-0808 February 1990 LER 90-003-00:on 900112,primary Containment & Reactor Vessel Isolation Control Sys Isolation Signals Initiated, Closing Inboard & Outboard Isolation Valves for Rwcu.Caused by Lifting Relief Valve.Opening Time reset.W/900208 Ltr ML20006E2851990-02-0707 February 1990 LER 90-002-00:on 900105,containment H2/O2 Analyzer Declared Inoperable During Containment Inerting.Caused by Reversed Tubing Connections in Installation of Analyzer Due to Mislabeling.Analyzer restored.W/900207 Ltr ML20006D5171990-02-0707 February 1990 LER 90-001-00:on 900108,Tech Spec Violation & Reactor Encl Ventilation Isolation Occurred.Caused by Personnel Error. Chief Operator Counseled on Importance of Communicating All Pertinent info.W/900207 Ltr ML20006A8801990-01-19019 January 1990 LER 89-015-00:on 891223 & 24,problem W/Reactor Protection Sys (Rps)/Uninterruptable Power Supply Static Inverter Caused Loss of Power to RPS Panel.Caused by Failure of Gate Drive Boost Card.Isolations reset.W/900119 Ltr ML20005F9441990-01-10010 January 1990 LER 89-060-00:on 891212,standby Gas Treatment Sys Charcoal Filter a Discovered to Be Degraded W/Possible Bypass Leakage Paths.On 891218,filter B Found W/Similar Condition.Caused by Failure of Spot Welds.Filters repaired.W/900110 Ltr ML20005E6841990-01-0303 January 1990 LER 89-059-00:on 891206,instrumentation & Controls Technician Inadvertently Grounded Test Jack,Resulting in Blown Fuse.Caused by Personnel Error.Fuse Replaced. Technicians counseled.W/900103 Ltr ML20042D1961989-12-29029 December 1989 LER 89-009-02:on 890820 & 0925,RCIC Sys Injections Into RCS Occurred During Startup Test.From 891023-26,three HPCI Sys Injections Into RCS Occurred During Test.Injections Anticipated.Startup Tests performed.W/891229 Ltr ML20005E3301989-12-29029 December 1989 LER 89-014-00:on 891202,unexpected Actuation of Primary Containment & Reactor Vessel Isolation Control Sys Occurred. Caused by Insufficient Guidance in General Plant Procedure. Appropriate Procedures Reviewed & revised.W/891229 Ltr ML20005E0961989-12-26026 December 1989 LER 89-058-00:on 891123,actuation of Group III Primary Containment & Reactor Vessel Isolation Control Sys Resulted in Automatic Isolation of Rwcu.Caused by Failure of Flow Summer Card.Card replaced.W/891226 Ltr ML20011D2291989-12-19019 December 1989 LER 89-057-00:on 891120,refuel Floor Secondary Containment Isolated on Low Flow Differential Pressure,Causing Initiation of Standby Gas Treatment Sys.Caused by Severe Storm.Normal Ventilation Restored to floor.W/891219 Ltr ML19332F8631989-12-13013 December 1989 LER 89-056-00:on 891119,unexpected Nuclear Steam Supply Shutoff Sys Group Iii,Div 4 Isolation Initiated ESF Actuation.Caused by Defective read-set Selector Switch. Switch repositioned.W/891213 Ltr ML19332F7761989-12-11011 December 1989 LER 89-013-00:on 891110,reactor Scram Occurred Following Main Turbine Trip,Causing Initiation Signals on HPCI & RCIC Sys Due to Spiking of Level Transformers.Caused by Design Error.Hpci Turbine secured.W/891211 Ltr ML19332F7751989-12-11011 December 1989 LER 89-012-00:on 891110,RWCU Sys Differential Flow Oscillations Observed While Placing RWCU 2A Filter/ Demineralizer Into Svc.Caused by Leakage in Reactor HX Tube Side Safety Relief Valve.Valve removed.W/891211 Ltr ML19332F2961989-11-29029 November 1989 LER 89-009-01:on 890820,eight RCIC Sys Injections Into RCS Occurred Under Purview of Facility start-up Test Program. Caused by Abnormal Plant Conditions Requiring Safety Sys Actuations.Rcic & HPCI Sys Tests completed.W/891129 Ltr ML19332D6331989-11-27027 November 1989 LER 89-011-00:on 891027,outboard Nuclear Steam Supply Shutoff Sys Isolation Valves Isolated.Caused by Personnel Error Due to Lack of Attention to Detail by Technicians. Event Discussed at All Hands meeting.W/891127 Ltr ML19332D6251989-11-27027 November 1989 LER 89-055-00:on 891025,reactor Protection Sys 1A Shunt Trip Breaker Tripped on Undervoltage,Causing Loss of Power to Distribution Panel 1AY160 & ESF Isolation.Caused by Relief Valve Failures.Isolations reset.W/891127 Ltr ML19332C1781989-11-17017 November 1989 LER 89-053-00:on 891022,control Room Personnel Manually Initiated Ventilation Sys Chlorine Isolation,Esf.Caused by High Vinyl Chloride Concentration in Outside Air Intake Plenum.Special Event Procedure implemented.W/891117 Ltr ML19332B9841989-11-15015 November 1989 LER 89-054-01:on 891025,discovered That Daily Channel Check Surveillance Requirement for Channel D High Level Trip Not Met.Caused by Procedural Deficiency Since Initial Plant Operation.Associated Log Procedures revised.W/891115 Ltr 1994-04-22
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217D1211999-09-30030 September 1999 Monthly Operating Repts for Sept 1999 for Lgs,Units 1 & 2. with ML20217A1691999-09-22022 September 1999 Part 21 Rept Re Engine Sys,Inc Controllers,Manufactured Between Dec 1997 & May 1999,that May Have Questionable Soldering Workmanship.Caused by Inadequate Personnel Training.Sent Rept to All Nuclear Customers ML20212A8861999-09-13013 September 1999 Safety Evaluation Authorizing First & Second 10 Yr Interval Inservice Insp Plan Requestss for Relief RR-01 ML20212A4481999-08-31031 August 1999 Monthly Operating Repts for Aug 1999 for Limerick Generating Station,Units 1 & 2.With ML20211E9891999-08-20020 August 1999 LGS Unit 2 Summary Rept for 970228 to 990525 Periodic ISI Rept Number 5 ML20210L7051999-07-31031 July 1999 Monthly Operating Repts for July 1999 for Limerick Generating Station,Units 1 & 2.With ML20209G0211999-06-30030 June 1999 GE-NE-B13-02010-33NP, Evaluation of Limerick Unit 2 Shroud Cracking for at Least One Fuel Cycle of Operation ML20209D7741999-06-30030 June 1999 Monthly Operating Repts for June 1999 for Limerick Generating Station,Units 1 & 2 ML20207H8331999-05-31031 May 1999 Non-proprietary Rev 0 to 1H61R, LGS - Unit 2 Core Shroud Ultrasonic Exam ML20195G4651999-05-31031 May 1999 Monthly Operating Rept for May 1999 for Lgs,Units 1 & 2 ML20209D7791999-05-31031 May 1999 Revised Monthly Operating Repts for May 1999 for Limerick Generating Station,Units 1 & 2 ML20195B3021999-05-0606 May 1999 Rev 0 to PECO-COLR-L2R5, COLR for Lgs,Unit 2 Reload 5 Cycle 6 ML20206N2901999-04-30030 April 1999 Monthly Operating Repts for Apr 1999 for Limerick Generating Station,Units 1 & 2.With ML20195G4761999-04-30030 April 1999 Revised Monthly Operating Repts for Apr 1999 for Lgs,Units 1 & 2 ML20206D8971999-04-22022 April 1999 Rev 2 to PECO-COLR-L1R7, COLR for Lgs,Unit 2 Reload 7, Cycle 8 ML20205N8341999-04-0101 April 1999 Part 21 Rept Re Automatic Switch Co Nuclear Grade Series X206380 & X206832 Solenoid Valves Ordered Without Lubricants That Were Shipped with Std Lubrication to PECO & Tva.Affected Plants Were Notified ML20205N9311999-03-31031 March 1999 Monthly Operating Repts for Mar 1999 for Limerick Generating Station,Units 1 & 2.With ML20204G9851999-03-11011 March 1999 Safety Evaluation Re Revised Emergency Action Levels for Limerick Generating Station,Units 1 & 2 ML20207J7461999-02-28028 February 1999 Monthly Operating Repts for Feb 1999 for Limerick,Units 1 & 2.With ML20199G2371999-01-31031 January 1999 Rev 0 to NEDO-32645, Limerick Generating Station,Units 1 & 2 SRV Setpoint Tolerance Relaxation Licensing Rept ML20199L5301999-01-19019 January 1999 Special Rept:On 981214,seismic Monitor Was Declared Inoperable.Caused by Spectral Analyzer Not Running.Attempted to Reboot Sys & Then Sent Spectral Analyzer to Vendor for Analysis & Rework.Upgraded Sys Will Be Operable by 990331 B110078, Rev 1 to GE-NE-B1100786-01, Surveillance Specimen Program Evaluation for Limerick Generating Station,Unit 11998-12-31031 December 1998 Rev 1 to GE-NE-B1100786-01, Surveillance Specimen Program Evaluation for Limerick Generating Station,Unit 1 ML20205K0381998-12-31031 December 1998 PECO Energy 1998 Annual Rept. with ML20199F9611998-12-31031 December 1998 Monthly Operating Repts for Dec 1998 for Limerick Generating Station.With ML20198C7151998-12-10010 December 1998 Rev 1 to COLR for LGS Unit 1,Reload 7,Cycle 8 ML20198A3871998-12-10010 December 1998 Safety Evaluation Supporting Licensee Response to GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power- Operated Gate Valves ML20206N4061998-11-30030 November 1998 Monthly Operating Repts for Nov 1998 for Limerick Generating Station,Units 1 & 2.With ML20199E3281998-11-23023 November 1998 Rev 2 to PECO-COLR-L2R4, COLR for Lgs,Unit 2,Reload 4,Cycle 5 ML20195C9771998-10-31031 October 1998 Monthly Operating Repts for Oct 1998 for Limerick Generating Station,Units 1 & 2.With ML20154H5691998-09-30030 September 1998 Monthly Operating Repts for Sept 1998 for Limerick Generating Station,Units 1 & 2.With ML20151X3511998-08-31031 August 1998 Monthly Operating Repts for Aug 1998 for Limerick Generating Station Units 1 & 2.With ML20237F0291998-08-27027 August 1998 Special Suppl Rept:On 960425,one Loose Part Detection Sys (Lpds) Was Identified to Be Inoperable.Initially Reported on 960531.Caused by Loose Parts Detector Module.Repairs Performed & Intermittent Ground No Longer Present ML20237D1041998-08-17017 August 1998 Books 1 & 2 of LGS Unit 1 Summary Rept for 960301-980521 Periodic ISI Rept 7 ML20237A7761998-08-10010 August 1998 SER Accepting Licensee Response to NRC Bulleting 95-002, Unexpected Clogging of RHR Pump Strainer While Operating in Suppression Pool Cooling Mode ML20236X7641998-07-31031 July 1998 Rev 0 to SIR-98-079, Response to NRC RAI Re RPV Structural Integrity at Lgs,Units 1 & 2 ML20237B4711998-07-31031 July 1998 Monthly Operating Repts for July 1998 for Limerick Generating Station,Units 1 & 2 ML20236N6751998-07-0909 July 1998 Part 21 & Deficiency Rept Re Notification of Potential Safety Hazard from Breakage of Cast Iron Suction Heads in Apkd Type Pumps.Caused by Migration of Suction Head Journal Sleeve Along Lower End of Pump Shaft.Will Inspect Pumps ML20151Z4881998-06-30030 June 1998 GE-NE-B1100786-02, Surveillance Specimen Program Evaluation for Limerick Generating Station,Unit 2 ML20236P9781998-06-30030 June 1998 Monthly Operating Repts for June 1998 for Limerick Generating Station,Units 1 & 2 ML20196K1801998-06-30030 June 1998 Annual 10CFR50.59 & Commitment Rev Rept for 970701-980630 for Lgs,Units 1 & 2. with ML20249B3501998-06-11011 June 1998 Rev 1 to PECO-COLR-L2R4, COLR for LGS Unit 2 Reload 4,Cycle 5 ML20249A5331998-05-31031 May 1998 Monthly Operating Repts for May 1998 for Limerick Units 1 & 2 ML20247M7071998-05-14014 May 1998 Safety Evaluation Supporting Amend 128 to License NPF-39 ML20217Q5101998-05-0404 May 1998 Safety Evaluation Supporting Amend 127 to License NPF-39 ML20247H5071998-04-30030 April 1998 Monthly Operating Repts for Apr 1998 for Limerick Generating Station ML20216F3601998-03-31031 March 1998 Monthly Operating Repts for Mar 1998 for Limerick Generating Station,Units 1 & 2 ML20217M0791998-03-31031 March 1998 Safety Evaluation Supporting Amends 125 & 89 to Licenses NPF-39 & NPF-85,respectively ML20217D5701998-03-20020 March 1998 Part 21 Rept 40 Re Governor Valve Stems Made of Inconel 718 Matl Which Caused Loss of Governor Control.Control Problems Have Been Traced to Valve Stems Mfg by Bw/Ip.Id of Carbon Spacer Should Be Increased to at Least .5005/.5010 ML20216F9471998-02-28028 February 1998 Monthly Operating Repts for Feb 1998 for Limerick Generating Station,Units 1 & 2 ML20216F3471998-02-28028 February 1998 Revised Monthly Operating Rept for Feb 1998 for Limerick Genrating Station,Unit 1 1999-09-30
[Table view] |
Text
%4 10 CFR 50.73 ,
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[ N L.: PHILADELPHIA ELECTRIC' COMPANY l LIMERICK GENER ATING STATION P. O BOX A SAN ATOG A, PENNSYLV ANI A 19464 (218) 3271200 Exv. 2000 m, s. u.c c.nu ec a e.c. ' January 10, 1990 4.,,
- u. . . ./.' C' .".'.",'U ".. .. .. Docket Nos. 50-352. 'i 50-353 ;
License Nos. NPF-39 NPF-85 ;
- U.S. Nuclear Regulatory Commission ,
Attn: Document Control Desk ,
N Washington, DCL 20555 +
X ,
SUBJECT:
Licensee Event Report- !
Limerick Generating Station - Units 1 and 2 '
This LER reports a condition that could have prevented the '
Standby Gas Treatment System (SGTS) from fulfilling its safety function and resulted in Operations prohibited by Technical Specifications. .This event'was caused by failure of charcoal ;
filter assembly welds that resulted in possible bypass leakage ;
paths through the filter acsembly.
Reference:
Docket Nos. 50-352 50-353 Report Number: 1-89-060 Revision" Number: 00 Discovery Date: December 13, 1989 Report Date: January 10, 1990 Facility: Limerick Generating Station l P.O. Box A, Sanatoga, PA 19464 l This LER is being submitted pursuant to the requirements of l 10 CFR 50.73(a)(2)(1)(B) and 10 CFR 50.73 (a)(2)(v)(C).
1 1
Very truly yours, il 7% ,
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u' b WAR:aj cci W. T. Russell, Administrator, Region I, USNRC T. J. Kenny, USilRC Senior Resident Inspector, LGS 9001170419 90o13o
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On December 12, 1989, the 'A' Standby Gas Treatment System (SGTS)
Charcoal Filter was discovered to be in a degraded condition with possible bypass leakage paths through the charcoal filter bed.
This condition provided the potential for SGTS Filter bypass leakage 'to be g: eater than the Technical Specifications (TS) surveillance allowable limit of 0.05% and could have prevented the SGTS from fulfilling its intended safety function. Several charcoal f\1ter assembly welds failed, creating openings (holes) at the bottom of the outer (downstream) screen of the filter assembly. On the 'A' SGTS Filter, approximately 2.5 cubic feet of charcoal had leaked out and the level of charcoal was lower
! than the normal full condition. On December 18, 1989, a similar degraded condition of the 'B' SGTS Charcoal' Filter was discovered l with approximately 0.1 cubic feet of charcoal having leaked out, but the level of charcoal remained at the normal full condition.
After a thorough inspection, the damaged filter screens were repaired, charcoal replaced, and the SGTS returned to operable status. We are continuing to evaluate the cause of the weld failures. As an augmented surveillance activity, each SGTS Charcoal Filter bed will be inspected monthly, following the TS required system flow test.
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Unit Conditions Prior to the Event: -
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Unit 1 Unit 2 ', ;
dperating Condition: 1 (Power Operation)* 4 (Cold Shutdown) f.
Reactor-Power: 100% 0% i i
These Operating Conditions existed immediately prior to discovery of the degraded condition of the Standby Gas Treatment System L
(SGTS)(EIIStBH) Charcoal Filters. However both units have '
operated at various reactor power levels since January 19, 1989, >
when the 'A' and.'B' SGTS Charcoal Filters were last inspected ~
during routine surveillance testing. In addition, operability of the SGTS was required to support Refuel Floor. Secondary Containment opert.bility from February 8, 1989 to March 30, 1989 ,
and from November 8, 1989 to December 9, 1989.
Description of the Events ,
During a routine maintenance activity, the SGTS Charcoal Filters were discovered to be daraged with possible bypass leakage paths '
through the charcoal filter bed. This condition provided the potential for SGTS Filter bypass leakage to be greater than the
!' Technical Specifications (TS) allowable limit of 0.05% and could have prevented the SGTS from fulfilling its intended Safety function to limit the release of radioactive material.
On December- 11, 1989, the 'A' SGTS Charcoal Filter was opened for a routine inspection and scheduled replacement of the filter bed charcoal. Approximately 2.5 cubic feet of a total of . ,
approximately 80 cubic feet of charcoal was discovered on the filter housing floor and the level of charcoal in the 8 inch thick filter bed was lower than the normal full condition. On December 12, all of the charcoal was removed from the filter bed o
as planned. A thorough inspection of the filter assembly revealed the source of loose charcoal to be from three openings (holes) at the bottom of the outer (downstream) screen of the filter assembly. An engineering evaluation of the filter screen holes determined that they were caused by failure of several small spot welds connecting the screen to the filter mounting frame. On December 13, at 0915 hours0.0106 days <br />0.254 hours <br />0.00151 weeks <br />3.481575e-4 months <br />, station personnel concluded that degradation of the screen and the lower than normal level of charcoal in the filter bed could have created a y,._ .
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bypass leakage path exceeding the TS surveillance allowable -
bypass leakage limit of 0.05%. Following screen' repairs, loading i new charcoal in the filter bed and performing required :
SGTS was returned to operable status
' surveillance tests, the 'A' at 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> on December 16, 1989. The 'A' SGTS was out of
' service for 134.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> total for the scheduled filter charcoal replacement and correction of the deficiency.
After discovery of the failed welds on the 'A' SGTS filter bed, station management decided to inspect the redundant 'B' SGTS filter bed for indications of a similar degradation. On December 14, 1989 with the 'B'.SGTS in operable status, a boroscope was -
used to inspect the 'B' SGTS Charcoal Filter. Approximately '
three quarters of the charcoal bed was inspected and no evidence of similar filter degradation was. observed. The inspection was .
not complete because the entire filter screen surface area was not accessible with the boroscope. Since no problems were identified by the inspection, station management concluded that i the 'B' SGTS was operable and would be fully inspected after the
'A' SGTS was returned to service.
, After completion of repairs to the 'A' SGTS filter bed, the 'B' ;
l SGTS was removed from service on December 18, and a complete visual inspection of the 'B' Charcoal Filter was conducted.
Approximately 0.1 cubic feet of loose charcoal was discovered on the filter housing floor in the area not accessible during the boroscope inspection. Similar to the 'A' filter, this charcoal H was due to a small opening of the filter bed outer screen where it was spot welded to the filter mounting frame. Although some charcoal leaked out, the charcoal filter bed was still filled above the screen height and there was no evidence of voids or potential bypass leakage paths. The 'B' SGTS was not considered inoperable as a result of this condition. However, station management conservatively concluded that the 'B' SGTS may have been in a condition that could have prevented the 'B' SGTS f rom 1
performing its intended function. Following the charcoal unloading, screen repair, loading of new charcoal in the filter l bed and performing required surveillance tests, the 'B' SGTS was i returned to operable status at 1730 hours0.02 days <br />0.481 hours <br />0.00286 weeks <br />6.58265e-4 months <br /> or. December 21. The
'B' SGTS was out of service 70.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> total for the filter
! charcoal replacement and corrections of the deficiency.
A four (4) hour. notification was made to the NRC on December 13, 1989, at 0947 hours0.011 days <br />0.263 hours <br />0.00157 weeks <br />3.603335e-4 months <br /> in accordance with 10 CFR 50.72 (b)(2)(iii)(C) because the event could have prevented the SGTS from performing its intended function to limit the release of radioactive material. A follow-up notification was made to the NRC on December 18, 1989 at 2100 hours0.0243 days <br />0.583 hours <br />0.00347 weeks <br />7.9905e-4 months <br />, when it was discovered that the 'B' SGTS filter had a similar, although less significant 3on. u.,
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s degradation. Accordingly, this report is being submitted in
have existed since January 19, 1989 when the 'A' and 'B' filters t
I were last inspected for routine surveillance. Therefore this:
Jeport is also being submitted in accordance with 10 CFR 50.73 ,
L (a)(2)(1)(B), "Any Operation or Conditiod Prohibited by the ;
Plants Technical Specifications," because the significant bypass leakage path discovered on the 'A' SGTS Charcoal Filter was s
assumed to be greater than the TS Surveillance 4.6.5.3 allowable limit of 0.05% and the required TS remedial actions were not
.taken.
Consequences of the Event
- The consequences of tnis event were minimal. There was no release of radioactive material to the environment and the system
'a' degradation was discovered as a result of the established '
surveillance and preventive maintenance programs. The exact duration this degraded condition existed is not known. However i it did not exist on January 19, 1989 when the 'A' and 'B' filters -
were last-inspected for routine surveillance.
l There were, however, greater potential consequences of this l condition. Normal SGTS lineup is with both the 'A' and 'B' SGTS '
I Filter trains aligned in the automatic start mode. Had the SGTS been required to limit the release of radioactive material in response to a Loss of Coolant Accident (LOCA) or Refueling Accident, both the 'A' and 'B' SGTS trains would have initiated.
Due to the discovered condition of the 'A' and 'B' SGTS Filters, the SGTS would not have performed its design function to remove 99.0% of all radioactive iodine from secondary containment effluent' gases as assumed in the Design Basis Accident (DBA) safety analyses. -
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sna w . u. ,, u a enc u au.am Cause of the Event: -
This event was. caused by holes in the SGTS charcoal filter ,
assemblies-created by failure of spot welds which connected the outer (downctream) screen to the filter mounting frame. The holes allowed charcoal to leak from the filter bed and increased the potential for' untreated filter bypass air flow. The exact cause of the spot weld failures is not known, but does not appear to be the result of operations, surveillance or maintenance activities.
The design of these charcoal filters is unique to the SGTS at Limerick Generating Station.
Corrective Actions:
1 Following discovery of the 'A' SGTS Charcoal Filter screen problem, on December 13, a Nonconformance Report (NCR) was issued and Engineering Department personnel initiated an investig,c.lon and. analysis of the problem. A second NCR was issued on December 19, when.a similar problem was discovered on the 'B' SGTS Charcoal Filter screen. Both the 'A' and 'B' filter outer screens were repaired using a silver solder, brazing procedure.
The affected areas (openings) of the screens were re-fitted and securely attached to the filter mounting frame. The filter manufacturer was consulted and concurred with the repair procedure used. Both filters were refilled with new charcoal and were tested to demonstrate acceptable bypass leakage before they were declared operable and returned to service.
~,
Actions Taken to Prevent Recurrence:
With the charcoal removed, each of the filter screens were examined completely for evidence of degradation (attachment weld failures). The only problems identified were on the outer (downstream) screen, where it connected to the lower mounting frame. The affected areas were limited to three welds on the 'A' filter and one weld on the 'B' filter. This failure was reported on the Nuclear Plant Reliability Data System.
The Engineering department is continuing its evaluation of the weld failures to determine the reason for their failure. As an goeu un
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f augmented surveillance. activity, a complete inspection of each .
j SGTS. Charcoal, Filter bed.will'be performed monthly, following the 'j TS required system flow test. Results of the engineering ;
evaluation of the weld failures will be provided in a supplement i to this report by May 15, 1990.- 1 g.
Previous Similar Occurrences:
1 None' 1
Cause~ Codes B -
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