|
---|
Category:LICENSEE EVENT REPORT (SEE ALSO AO
MONTHYEARML17313B0751999-08-27027 August 1999 LER 99-002-00:on 990730,test Mode Trip Bypass for EDG Output Breakers Not Surveilled.Cause Under Investigation.Operations Personnel Conservatively Invoked SR 3.0.3 for SR 3.8.1.13. with 990827 Ltr ML17313B0191999-07-16016 July 1999 LER 99-005-00:on 990618,RT on Low DNBR Was Noted.Caused by Hardware Induced Calculation Error.Cr Operator Was Taken to Place Reactor in Stable Condition IAW Appropriate Operating Procedure ML17313A9281999-05-0707 May 1999 LER 99-004-00:on 990408,PSV Lift Pressures Were Outside of TS Limits.Caused by Lift Pressure Setpoint Drift.Psvs Have Been Tested,Disassembled,Inspected,Reassembled & Certified at Wyle Labs ML17313A8951999-04-14014 April 1999 LER 99-003-00:on 990317,required Surveillance Requirement Not Completed Due to Deficient Procedure,Was Determined. Caused by Cognitive Personnel Error.St Procedures Revised to Require Chiller to Be Operating & Oil Temperature Checked ML17313A8921999-04-13013 April 1999 LER 98-003-01:on 980902,discovered That MSSV as-found Lift Pressures Were Outside TS Limits.Caused by Bonding of Valve Disc to Nozzle Seat.Affected Valves Were Adjusted,Retested & Returned to Svc ML17313A8891999-04-0909 April 1999 LER 99-001-00:on 990310,RT on High Pressurizer Pressure Was Noted.Caused by Loss of Heat Removal.Cr Supervisor Was Removed from Shift Duties for Diagnostics Skills Training. with 990409 Ltr ML17313A8361999-03-0101 March 1999 LER 99-001-00:on 990103,TS Violation for Power Dependent Insertion Limit Alarm Being Inoperable.Caused by Personnel Error.Revised Procedure to Clarify How Computer Point Is to Be Returned to Scan Mode.With 990302 Ltr ML17313A7701999-01-15015 January 1999 LER 96-008-00:on 960507,inadequate Procedure Results in Nuclear Power Channels Not Calibrated During Power Ascension Tests Occurred.Caused by Deficient Procedure.Procedure Revised ML17313A6611998-10-24024 October 1998 LER 98-008-00:on 980729,EQ of Electrical Connectors Were Not Adequately Demonstrated.Caused Because Test Was Conducted with Only Single Lv Connector & Without Fully Ranged Inputs. Revised EQ Requirements ML17313A5961998-09-14014 September 1998 LER 98-002-00:on 980814,B Train H Recombiner Was Noted Inoperable Due to cross-wired Power Receptacle.Cause of Event Is Under investigation.Cross-wired Power Supply Receptacle for B Train H Recombiner Was re-wired ML17313A5761998-09-0808 September 1998 LER 98-003-01:on 980113,discovered That One Channel of RWT Level Sys Had Failed High.Caused by Water Intrusion Into Electrical Termination Pull Box.Weep Holes Were Drilled Into Bottoms of Pull Boxes Nearest Level Transmitters ML17313A5591998-08-28028 August 1998 LER 98-001-00:on 980730,entered TS 3.0.3 Due to Safety Injection Flow Instruments Being Removed from Svc.Caused by Personnel Error.Transmitters Were Unisolated & Returned to svc.W/980828 Ltr ML17313A5201998-07-30030 July 1998 LER 98-004-00:on 980630,personnel Discovered That Pressure Safety Valve Had Not Received Periodic Set Pressure Test for ASME Class 1 Pressure Safety Valve.Caused by Personnel Error.Pressure Safety Valve reviewed.W/980730 Ltr ML17313A4671998-06-19019 June 1998 LER 98-007-00:on 980520,CR Personnel Observed Flow & Pressure Perturbations on Chemical & Vol Control Sys Letdown Sys.Caused by Cyclic Fatigue Due to Dynamic Pressure Transients.Unit Letdown Piping Replaced ML17313A4131998-06-0505 June 1998 LER 98-006-00:on 980507,determined That Plant Was Outside Design Basis Due to SI Discharge Check Valve Reverse Flow. Check Valve Was Disassembled,Examined & Reassembled, Whereupon Valve Met Acceptance Criteria ML17313A3951998-05-26026 May 1998 LER 98-005-00:on 980428,noted That Required Response Time Testing Had Not Been Performed.Caused by Personnel Error. Coached I&C Personnel Responsible for Reviewing Work Authorization Documentation ML17313A3251998-04-0101 April 1998 LER 98-004-00:on 980304,safety Valves as-found Pressures Out of Tolerance.Cause of Event Is Under Investigation.Three Mssv'S & Psv Will Be Replaced W/Refurbished & Recertified Valves During Refueling Outage U1R7 ML17313A3131998-03-21021 March 1998 LER 98-001-00:on 980301,surveillance Test Deficiency Found During Qaa Leads to TS 3.0.3/4.0.3 Entry.Caused by Personnel Error.Personnel Responsible for Inadequately Performed SR Were Coached ML17313A2251998-03-0505 March 1998 LER 93-005-00:on 930309,CR Personnel Discovered Missed TS LCO Action & Subsequently Performed Surveillance Satisfactorily.Caused by Personnel Error.Appropriate Disciplinary Action issued.W/980305 Ltr ML17313A2241998-02-26026 February 1998 LER 98-001-00:on 980130,reactor Protection & ESFAS Instrumentation Not Bypassed within one-hour Allowed by TS Occurred.Caused by Inadequate Procedures.Expectation to Detect Alarm Conditions Was Emphasized to CR Personnel ML17313A2081998-02-10010 February 1998 LER 97-007-00:on 971006,TS Violation Occurred Due to Inadequate Shutdown Cooling Flow During Modes 5 & 6 Operation.Independent Investigation of Event Was Conducted IAW APS CA program.W/980210 Ltr ML17313A2041998-02-0505 February 1998 LER 97-006-00:on 971028,missed TS 4.0.5 SR Was Noted.Caused by Personnel Error.Independent Investigation of Event Is Being Conducted IAW W/Aps Corrective Action Program ML17313A1201997-11-12012 November 1997 LER 97-006-00:on 971020,manual Reactor Trip Occurred Due to Vibration & Bearing Temp Increases in Reactor Coolant Pump. Caused by Failed Lower Journal Bearing.Bearing Assembly Was Disassembled,Inspected & Rebuilt ML17312B7181997-10-0707 October 1997 LER 97-003-00:on 970907,inadvertent Loss of Power & EDG Start Occurred Due to Procedural Error.Changed Train a & Train B Edg/Ist ST Procedures to Consistently Reflect Proper Pretest Staging Hand switches.W/971007 Ltr ML17312B7051997-09-26026 September 1997 LER 97-003-01:on 970215,seven Main Steam Safety Valves Were Found Out of Tolerance Prior to Refueling Outage.Safety Analysis Performed Based Upon as-found MSSV Data Which Demonstrated That MSSVs Would Perform Safety Functions ML17312B5531997-07-0707 July 1997 LER 97-002-00:on 970528,SR for Core Protection Was Not Performed Due to Inadequate Procedures.Revised Procedures ML17312B5501997-07-0707 July 1997 LER 97-003-00:on 970211,notified of Trevitest Activities Indicating That Total of Seven MSSVs Had as-found Lift Set Pressures Greater than 3 Percent Allowed by TS 3.7.1.1. Investigation Conducted.Seven MSSVs replaced.W/970707 Ltr ML17312B4971997-06-13013 June 1997 LER 97-002-00:on 970531,RT Occurred.Caused by Spurious Opening of All Four Rt Switchgear Breakers.Independent Investigation of Event Being Conducted in Accordance W/Util Corrective Action Program ML17312B1461996-12-17017 December 1996 LER 96-007-00:on 961119,surveillance Test Deficiencies Were Found During GL 96-01 Review Leading to TS 3.0.3 Entries. Caused by Increase in Scope of Required Testing.Supplement Will Be submitted.W/961217 Ltr ML17312A9511996-09-0404 September 1996 LER 96-003-00:on 960809,open Auxiliary Bldg Door Caused Full Bldg Essential Filtration Inoperability.Caused by Personnel Error.C/As Under consideration.W/960904 Ltr ML17312A8641996-07-17017 July 1996 LER 96-001-00:on 960621,inaccurate Gas Calculations for Post Accident Sampling Sys Occurred.Caused by Surveillance Test Worksheet Errors.Independent Investigation of Event Being conducted.W/960717 Ltr ML17300B2541996-06-11011 June 1996 LER 96-001-01:on 960404,inappropriate Grounding of Equipment Resulted in Condition Outside Design Basis of Plant. Established Fire Watches Required for Affected Areas ML17312A8081996-06-0909 June 1996 LER 96-002-00:on 960514,Tech Spec Violation Occurred Due to Erroneous Surveillance Requirement.Caused by Incorporation of C-E Generic Ts.Investigation Being conducted.W/960609 Ltr ML17312A7751996-05-17017 May 1996 LER 96-003-00:on 960122,missed Surveillance for Logic Check of Logs 1 & 2 Safety Excore Bypasses.Caused by Procedural Error.Log Power Functional Test Revised to Check Logs 1 & 2 Bypasses Regardless of Power level.W/960517 Ltr ML17312A7511996-05-0606 May 1996 LER 96-001-00:on 960404,smoke Discovered in Back Boards Area of CR by Security Officer,Performing Hourly Fire Watch Tour. Caused by Improperly Grounded Circuit.Investigation for Inappropriate Grounding of Low Voltage Power Sys Initiated ML17312A7241996-04-25025 April 1996 LER 96-002-00:on 960401,inappropriate Work Practice Resulted in Esfa of Train B Edg.Night Order Was Issued to All Three Units Describing event.W/960425 Ltr ML17312A6861996-04-0606 April 1996 LER 95-007-01:on 950512,determined That Bench Settings of air-operated Letdown & Containment Isolation Valves Adversely Affected Ability of Valves to Perform 10CFR50 App R Safety Function.Affected Valves Modified ML17312A5631996-02-22022 February 1996 LER 95-016-00:on 951212,containment Spray TS Violation Occurred Due to Unrecognized Valve Failure.Shim/Band Was Placed Around Stator of 1JSIBUV665 Motor Operator to Maintain Stator in Correct position.W/960222 Ltr ML17311B3381996-01-0909 January 1996 LER 95-014-00:on 951209,reactor Tripped Following Degradation of Main FW Flow.Caused by Malfunction of Fwcs Power supply,NNN-D11,transfer switch.NNN-D11 Aligned to Normal Power supply.W/960109 Ltr ML17311B3331995-12-31031 December 1995 LER 95-013-00:on 951201,AFW Sys Was Outside Design Basis of Plant.Caused by Design Error.Performed Assessment to Demonstrate That Existing Condition Does Not Pose Addl Safety concerns.W/951231 Ltr ML17311B2801995-11-23023 November 1995 LER 95-011-00:on 951018,identified Procedural Deficiency W/Msiv & FWIV ISTs Due to Personnel Error.Verified Operability of MSIVs & FWIVs.W/951123 Ltr ML17311B2531995-10-20020 October 1995 LER 95-002-00:on 950924,identified That Abnormal Blowdown Valves to Blowdown Flash Tank (Bft) Isolated,Resulting in Reactor Core Power Exceeding 3,800 Mwt Due to Personnel Error.Procedure for Aligning Blowdown to Bft Revised ML17311B1991995-09-21021 September 1995 LER 95-010-00:on 950727,equipment Qualification of Air Handling Unit Caused Essential Cw Pump to Be Inoperable. Used Work Orders to Drill Weep Holes in Motor Lead Connection boxes.W/950921 Ltr ML17311B1741995-09-0404 September 1995 LER 95-004-01:on 950329,containment Electrical Penetration Overcurrent Protective Devices Found Outside Design Basis. Caused by Error on Part of Original Architect Engineer. Modified Affected Circuits Critical to Normal Operational ML17311B1561995-08-27027 August 1995 LER 95-003-00:on 950729,switchyard Voltage Dropped Below Administratively Imposed Limit of 524 Kv for Approx 10 Seconds Due to Transient Grid Voltage.No C/A Taken Since Transmission Sys Transient Short duration.W/950827 Ltr ML17311B1551995-08-25025 August 1995 LER 95-002-01:on 950303,identified That Slb Analyses Failed to Consider as Initial Condition One Percent SDM for All Rods in (ARI) Due to Lack of Coordination & Unclear Div of Responsibilities.Ari Core Data Book SDM Curves Modified ML17311B1211995-08-16016 August 1995 LER 95-005-00:on 950717,RT on Low SG Water Level Was Result Following Degradation of MFW Flow.Completed Evaluation of Event ML17311B0841995-07-28028 July 1995 LER 94-005-01:on 941019,completed TS Required Shutdown Due to Expiration of LCO Time Limit.Design Change Options Identified & Will Be Reviewed to Determine If Valve &/Or Motor Operator Replacement or Mod Necessary ML17311B0721995-07-20020 July 1995 LER 95-004-00:on 950706,identified Four Occassions Between 950407 & 0630 When Conditional Surveillance in TS LCO 3.8.4.1 Action a Not Performed Due to Inattention to Detail. CR Copy of Temporary Procedure 40TP-9ZZ04 Corrected ML17311B0081995-07-0606 July 1995 LER 95-003-00:on 950613,TS LCO 3.0.3 Entered Following Loss of Both Trains of Essential Cw Sys & Both Hydrogen Recombiners.Caused by Spurious Actuations Due to Broken EDG Speed Probe Connector.Connector replaced.W/950706 Ltr 1999-08-27
[Table view] Category:RO)
MONTHYEARML17313B0751999-08-27027 August 1999 LER 99-002-00:on 990730,test Mode Trip Bypass for EDG Output Breakers Not Surveilled.Cause Under Investigation.Operations Personnel Conservatively Invoked SR 3.0.3 for SR 3.8.1.13. with 990827 Ltr ML17313B0191999-07-16016 July 1999 LER 99-005-00:on 990618,RT on Low DNBR Was Noted.Caused by Hardware Induced Calculation Error.Cr Operator Was Taken to Place Reactor in Stable Condition IAW Appropriate Operating Procedure ML17313A9281999-05-0707 May 1999 LER 99-004-00:on 990408,PSV Lift Pressures Were Outside of TS Limits.Caused by Lift Pressure Setpoint Drift.Psvs Have Been Tested,Disassembled,Inspected,Reassembled & Certified at Wyle Labs ML17313A8951999-04-14014 April 1999 LER 99-003-00:on 990317,required Surveillance Requirement Not Completed Due to Deficient Procedure,Was Determined. Caused by Cognitive Personnel Error.St Procedures Revised to Require Chiller to Be Operating & Oil Temperature Checked ML17313A8921999-04-13013 April 1999 LER 98-003-01:on 980902,discovered That MSSV as-found Lift Pressures Were Outside TS Limits.Caused by Bonding of Valve Disc to Nozzle Seat.Affected Valves Were Adjusted,Retested & Returned to Svc ML17313A8891999-04-0909 April 1999 LER 99-001-00:on 990310,RT on High Pressurizer Pressure Was Noted.Caused by Loss of Heat Removal.Cr Supervisor Was Removed from Shift Duties for Diagnostics Skills Training. with 990409 Ltr ML17313A8361999-03-0101 March 1999 LER 99-001-00:on 990103,TS Violation for Power Dependent Insertion Limit Alarm Being Inoperable.Caused by Personnel Error.Revised Procedure to Clarify How Computer Point Is to Be Returned to Scan Mode.With 990302 Ltr ML17313A7701999-01-15015 January 1999 LER 96-008-00:on 960507,inadequate Procedure Results in Nuclear Power Channels Not Calibrated During Power Ascension Tests Occurred.Caused by Deficient Procedure.Procedure Revised ML17313A6611998-10-24024 October 1998 LER 98-008-00:on 980729,EQ of Electrical Connectors Were Not Adequately Demonstrated.Caused Because Test Was Conducted with Only Single Lv Connector & Without Fully Ranged Inputs. Revised EQ Requirements ML17313A5961998-09-14014 September 1998 LER 98-002-00:on 980814,B Train H Recombiner Was Noted Inoperable Due to cross-wired Power Receptacle.Cause of Event Is Under investigation.Cross-wired Power Supply Receptacle for B Train H Recombiner Was re-wired ML17313A5761998-09-0808 September 1998 LER 98-003-01:on 980113,discovered That One Channel of RWT Level Sys Had Failed High.Caused by Water Intrusion Into Electrical Termination Pull Box.Weep Holes Were Drilled Into Bottoms of Pull Boxes Nearest Level Transmitters ML17313A5591998-08-28028 August 1998 LER 98-001-00:on 980730,entered TS 3.0.3 Due to Safety Injection Flow Instruments Being Removed from Svc.Caused by Personnel Error.Transmitters Were Unisolated & Returned to svc.W/980828 Ltr ML17313A5201998-07-30030 July 1998 LER 98-004-00:on 980630,personnel Discovered That Pressure Safety Valve Had Not Received Periodic Set Pressure Test for ASME Class 1 Pressure Safety Valve.Caused by Personnel Error.Pressure Safety Valve reviewed.W/980730 Ltr ML17313A4671998-06-19019 June 1998 LER 98-007-00:on 980520,CR Personnel Observed Flow & Pressure Perturbations on Chemical & Vol Control Sys Letdown Sys.Caused by Cyclic Fatigue Due to Dynamic Pressure Transients.Unit Letdown Piping Replaced ML17313A4131998-06-0505 June 1998 LER 98-006-00:on 980507,determined That Plant Was Outside Design Basis Due to SI Discharge Check Valve Reverse Flow. Check Valve Was Disassembled,Examined & Reassembled, Whereupon Valve Met Acceptance Criteria ML17313A3951998-05-26026 May 1998 LER 98-005-00:on 980428,noted That Required Response Time Testing Had Not Been Performed.Caused by Personnel Error. Coached I&C Personnel Responsible for Reviewing Work Authorization Documentation ML17313A3251998-04-0101 April 1998 LER 98-004-00:on 980304,safety Valves as-found Pressures Out of Tolerance.Cause of Event Is Under Investigation.Three Mssv'S & Psv Will Be Replaced W/Refurbished & Recertified Valves During Refueling Outage U1R7 ML17313A3131998-03-21021 March 1998 LER 98-001-00:on 980301,surveillance Test Deficiency Found During Qaa Leads to TS 3.0.3/4.0.3 Entry.Caused by Personnel Error.Personnel Responsible for Inadequately Performed SR Were Coached ML17313A2251998-03-0505 March 1998 LER 93-005-00:on 930309,CR Personnel Discovered Missed TS LCO Action & Subsequently Performed Surveillance Satisfactorily.Caused by Personnel Error.Appropriate Disciplinary Action issued.W/980305 Ltr ML17313A2241998-02-26026 February 1998 LER 98-001-00:on 980130,reactor Protection & ESFAS Instrumentation Not Bypassed within one-hour Allowed by TS Occurred.Caused by Inadequate Procedures.Expectation to Detect Alarm Conditions Was Emphasized to CR Personnel ML17313A2081998-02-10010 February 1998 LER 97-007-00:on 971006,TS Violation Occurred Due to Inadequate Shutdown Cooling Flow During Modes 5 & 6 Operation.Independent Investigation of Event Was Conducted IAW APS CA program.W/980210 Ltr ML17313A2041998-02-0505 February 1998 LER 97-006-00:on 971028,missed TS 4.0.5 SR Was Noted.Caused by Personnel Error.Independent Investigation of Event Is Being Conducted IAW W/Aps Corrective Action Program ML17313A1201997-11-12012 November 1997 LER 97-006-00:on 971020,manual Reactor Trip Occurred Due to Vibration & Bearing Temp Increases in Reactor Coolant Pump. Caused by Failed Lower Journal Bearing.Bearing Assembly Was Disassembled,Inspected & Rebuilt ML17312B7181997-10-0707 October 1997 LER 97-003-00:on 970907,inadvertent Loss of Power & EDG Start Occurred Due to Procedural Error.Changed Train a & Train B Edg/Ist ST Procedures to Consistently Reflect Proper Pretest Staging Hand switches.W/971007 Ltr ML17312B7051997-09-26026 September 1997 LER 97-003-01:on 970215,seven Main Steam Safety Valves Were Found Out of Tolerance Prior to Refueling Outage.Safety Analysis Performed Based Upon as-found MSSV Data Which Demonstrated That MSSVs Would Perform Safety Functions ML17312B5531997-07-0707 July 1997 LER 97-002-00:on 970528,SR for Core Protection Was Not Performed Due to Inadequate Procedures.Revised Procedures ML17312B5501997-07-0707 July 1997 LER 97-003-00:on 970211,notified of Trevitest Activities Indicating That Total of Seven MSSVs Had as-found Lift Set Pressures Greater than 3 Percent Allowed by TS 3.7.1.1. Investigation Conducted.Seven MSSVs replaced.W/970707 Ltr ML17312B4971997-06-13013 June 1997 LER 97-002-00:on 970531,RT Occurred.Caused by Spurious Opening of All Four Rt Switchgear Breakers.Independent Investigation of Event Being Conducted in Accordance W/Util Corrective Action Program ML17312B1461996-12-17017 December 1996 LER 96-007-00:on 961119,surveillance Test Deficiencies Were Found During GL 96-01 Review Leading to TS 3.0.3 Entries. Caused by Increase in Scope of Required Testing.Supplement Will Be submitted.W/961217 Ltr ML17312A9511996-09-0404 September 1996 LER 96-003-00:on 960809,open Auxiliary Bldg Door Caused Full Bldg Essential Filtration Inoperability.Caused by Personnel Error.C/As Under consideration.W/960904 Ltr ML17312A8641996-07-17017 July 1996 LER 96-001-00:on 960621,inaccurate Gas Calculations for Post Accident Sampling Sys Occurred.Caused by Surveillance Test Worksheet Errors.Independent Investigation of Event Being conducted.W/960717 Ltr ML17300B2541996-06-11011 June 1996 LER 96-001-01:on 960404,inappropriate Grounding of Equipment Resulted in Condition Outside Design Basis of Plant. Established Fire Watches Required for Affected Areas ML17312A8081996-06-0909 June 1996 LER 96-002-00:on 960514,Tech Spec Violation Occurred Due to Erroneous Surveillance Requirement.Caused by Incorporation of C-E Generic Ts.Investigation Being conducted.W/960609 Ltr ML17312A7751996-05-17017 May 1996 LER 96-003-00:on 960122,missed Surveillance for Logic Check of Logs 1 & 2 Safety Excore Bypasses.Caused by Procedural Error.Log Power Functional Test Revised to Check Logs 1 & 2 Bypasses Regardless of Power level.W/960517 Ltr ML17312A7511996-05-0606 May 1996 LER 96-001-00:on 960404,smoke Discovered in Back Boards Area of CR by Security Officer,Performing Hourly Fire Watch Tour. Caused by Improperly Grounded Circuit.Investigation for Inappropriate Grounding of Low Voltage Power Sys Initiated ML17312A7241996-04-25025 April 1996 LER 96-002-00:on 960401,inappropriate Work Practice Resulted in Esfa of Train B Edg.Night Order Was Issued to All Three Units Describing event.W/960425 Ltr ML17312A6861996-04-0606 April 1996 LER 95-007-01:on 950512,determined That Bench Settings of air-operated Letdown & Containment Isolation Valves Adversely Affected Ability of Valves to Perform 10CFR50 App R Safety Function.Affected Valves Modified ML17312A5631996-02-22022 February 1996 LER 95-016-00:on 951212,containment Spray TS Violation Occurred Due to Unrecognized Valve Failure.Shim/Band Was Placed Around Stator of 1JSIBUV665 Motor Operator to Maintain Stator in Correct position.W/960222 Ltr ML17311B3381996-01-0909 January 1996 LER 95-014-00:on 951209,reactor Tripped Following Degradation of Main FW Flow.Caused by Malfunction of Fwcs Power supply,NNN-D11,transfer switch.NNN-D11 Aligned to Normal Power supply.W/960109 Ltr ML17311B3331995-12-31031 December 1995 LER 95-013-00:on 951201,AFW Sys Was Outside Design Basis of Plant.Caused by Design Error.Performed Assessment to Demonstrate That Existing Condition Does Not Pose Addl Safety concerns.W/951231 Ltr ML17311B2801995-11-23023 November 1995 LER 95-011-00:on 951018,identified Procedural Deficiency W/Msiv & FWIV ISTs Due to Personnel Error.Verified Operability of MSIVs & FWIVs.W/951123 Ltr ML17311B2531995-10-20020 October 1995 LER 95-002-00:on 950924,identified That Abnormal Blowdown Valves to Blowdown Flash Tank (Bft) Isolated,Resulting in Reactor Core Power Exceeding 3,800 Mwt Due to Personnel Error.Procedure for Aligning Blowdown to Bft Revised ML17311B1991995-09-21021 September 1995 LER 95-010-00:on 950727,equipment Qualification of Air Handling Unit Caused Essential Cw Pump to Be Inoperable. Used Work Orders to Drill Weep Holes in Motor Lead Connection boxes.W/950921 Ltr ML17311B1741995-09-0404 September 1995 LER 95-004-01:on 950329,containment Electrical Penetration Overcurrent Protective Devices Found Outside Design Basis. Caused by Error on Part of Original Architect Engineer. Modified Affected Circuits Critical to Normal Operational ML17311B1561995-08-27027 August 1995 LER 95-003-00:on 950729,switchyard Voltage Dropped Below Administratively Imposed Limit of 524 Kv for Approx 10 Seconds Due to Transient Grid Voltage.No C/A Taken Since Transmission Sys Transient Short duration.W/950827 Ltr ML17311B1551995-08-25025 August 1995 LER 95-002-01:on 950303,identified That Slb Analyses Failed to Consider as Initial Condition One Percent SDM for All Rods in (ARI) Due to Lack of Coordination & Unclear Div of Responsibilities.Ari Core Data Book SDM Curves Modified ML17311B1211995-08-16016 August 1995 LER 95-005-00:on 950717,RT on Low SG Water Level Was Result Following Degradation of MFW Flow.Completed Evaluation of Event ML17311B0841995-07-28028 July 1995 LER 94-005-01:on 941019,completed TS Required Shutdown Due to Expiration of LCO Time Limit.Design Change Options Identified & Will Be Reviewed to Determine If Valve &/Or Motor Operator Replacement or Mod Necessary ML17311B0721995-07-20020 July 1995 LER 95-004-00:on 950706,identified Four Occassions Between 950407 & 0630 When Conditional Surveillance in TS LCO 3.8.4.1 Action a Not Performed Due to Inattention to Detail. CR Copy of Temporary Procedure 40TP-9ZZ04 Corrected ML17311B0081995-07-0606 July 1995 LER 95-003-00:on 950613,TS LCO 3.0.3 Entered Following Loss of Both Trains of Essential Cw Sys & Both Hydrogen Recombiners.Caused by Spurious Actuations Due to Broken EDG Speed Probe Connector.Connector replaced.W/950706 Ltr 1999-08-27
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML17300B3811999-09-30030 September 1999 Monthly Operating Repts for Sept 1999 for Pvngs,Units 1,2 & 3.With 991007 Ltr ML17300B3271999-08-31031 August 1999 Monthly Operating Rept for Aug 1999 for Pvngs,Units 1,2 & 3 ML17313B0751999-08-27027 August 1999 LER 99-002-00:on 990730,test Mode Trip Bypass for EDG Output Breakers Not Surveilled.Cause Under Investigation.Operations Personnel Conservatively Invoked SR 3.0.3 for SR 3.8.1.13. with 990827 Ltr ML17313B0611999-07-31031 July 1999 Monthly Operating Repts for July 1999 for Pvngs,Units 1,2 & 3.With 990810 Ltr ML17313B0191999-07-16016 July 1999 LER 99-005-00:on 990618,RT on Low DNBR Was Noted.Caused by Hardware Induced Calculation Error.Cr Operator Was Taken to Place Reactor in Stable Condition IAW Appropriate Operating Procedure ML17300B3151999-06-30030 June 1999 Monthly Operating Repts for June 1999 for Pvngs,Units 1,2 & 3.With 990714 Ltr ML17313A9921999-06-21021 June 1999 Special Rept:On 990525,RMS mini-computer Was Removed from Service to Implement Yr 2000 Mod & Was OOS Longer than 72 H Allowed.Caused by Planned Y2K Mods.Preplanned Alternate Sampling Program Was Initiated ML17313A9911999-06-18018 June 1999 Special Rept:On 990510,loose-part Detection Sys Channel 2 Was Declared Inoperable.Caused by Malfunction of Mineral Cable Connector to Accelerometer.Licensee Will Implement Modifications Which Will Enhance loose-part Detection Sys ML17313A9731999-05-31031 May 1999 Monthly Operating Repts for May 1999 for Pvngs,Units 1,2 & 3.With 990608 Ltr ML17313A9281999-05-0707 May 1999 LER 99-004-00:on 990408,PSV Lift Pressures Were Outside of TS Limits.Caused by Lift Pressure Setpoint Drift.Psvs Have Been Tested,Disassembled,Inspected,Reassembled & Certified at Wyle Labs ML17313A9201999-04-30030 April 1999 Monthly Operating Repts for Apr 1999 for Pvngs,Units 1,2 & 3.With 990512 Ltr ML17313A8951999-04-14014 April 1999 LER 99-003-00:on 990317,required Surveillance Requirement Not Completed Due to Deficient Procedure,Was Determined. Caused by Cognitive Personnel Error.St Procedures Revised to Require Chiller to Be Operating & Oil Temperature Checked ML17313A8921999-04-13013 April 1999 LER 98-003-01:on 980902,discovered That MSSV as-found Lift Pressures Were Outside TS Limits.Caused by Bonding of Valve Disc to Nozzle Seat.Affected Valves Were Adjusted,Retested & Returned to Svc ML17313A8891999-04-0909 April 1999 LER 99-001-00:on 990310,RT on High Pressurizer Pressure Was Noted.Caused by Loss of Heat Removal.Cr Supervisor Was Removed from Shift Duties for Diagnostics Skills Training. with 990409 Ltr ML17300B3071999-03-31031 March 1999 Seismic Portion of Submittal-Only Screening Review of Palo Verde Nuclear Generating Station Units Ipeee. ML17313A8801999-03-31031 March 1999 Monthly Operating Repts for Mar 1999 for Pvngs,Units 1,2 & 3.With 990412 Ltr ML20207M9231999-03-12012 March 1999 Amended Part 21 Rept Re Cooper-Bessemer Ksv EDG Power Piston Failure.Total of 198 or More Pistons Have Been Measured at Seven Different Sites.All Potentially Defective Pistons Have Been Removed from Svc Based on Encl Results ML20207H7471999-03-10010 March 1999 1999 Emergency Preparedness Exercise 99-E-AEV-03003 ML17313A8361999-03-0101 March 1999 LER 99-001-00:on 990103,TS Violation for Power Dependent Insertion Limit Alarm Being Inoperable.Caused by Personnel Error.Revised Procedure to Clarify How Computer Point Is to Be Returned to Scan Mode.With 990302 Ltr ML17313A8501999-02-28028 February 1999 Monthly Operating Repts for Feb 1999 for Palo Verde Nuclear Generating Station.With 990311 Ltr ML17313A7791999-02-0505 February 1999 Safety Evaluation Accepting Licensee Rev to Emergency Plan That Would Result in Two Less Radiation Protection Positions Immediatelu Available During Emergencies ML17313A8061999-01-31031 January 1999 Monthly Operating Repts for Jan 1999 for Pvngs,Units 1,2 & 3.With 990218 Ltr ML17313A7701999-01-15015 January 1999 LER 96-008-00:on 960507,inadequate Procedure Results in Nuclear Power Channels Not Calibrated During Power Ascension Tests Occurred.Caused by Deficient Procedure.Procedure Revised ML17313A7381998-12-31031 December 1998 Monthly Operating Repts for Dec 1998 for Palo Verde Nuclear Generating Station,Units 1,2 & 3.With 990113 Ltr ML20206H2101998-12-31031 December 1998 SCE 1998 Annual Rept ML17313A7031998-11-30030 November 1998 Monthly Operating Repts for Nov 1998 for Pvngs,Unit 1,2 & 3. with 981209 Ltr ML17313A6701998-11-0404 November 1998 Rev 2 to PVNGS Unit 2 Colr. ML17313A6741998-10-31031 October 1998 Monthly Operating Repts for Oct 1998 for Pvngs,Units 1,2 & 3.With 981109 Ltr ML17313A6611998-10-24024 October 1998 LER 98-008-00:on 980729,EQ of Electrical Connectors Were Not Adequately Demonstrated.Caused Because Test Was Conducted with Only Single Lv Connector & Without Fully Ranged Inputs. Revised EQ Requirements ML17313A6561998-09-30030 September 1998 Monthly Operating Rept for Sept 1998 for PVNGS Units 1,2 & 3.With 981007 Ltr ML17313A5961998-09-14014 September 1998 LER 98-002-00:on 980814,B Train H Recombiner Was Noted Inoperable Due to cross-wired Power Receptacle.Cause of Event Is Under investigation.Cross-wired Power Supply Receptacle for B Train H Recombiner Was re-wired ML17313A5761998-09-0808 September 1998 LER 98-003-01:on 980113,discovered That One Channel of RWT Level Sys Had Failed High.Caused by Water Intrusion Into Electrical Termination Pull Box.Weep Holes Were Drilled Into Bottoms of Pull Boxes Nearest Level Transmitters ML17313A5591998-08-28028 August 1998 LER 98-001-00:on 980730,entered TS 3.0.3 Due to Safety Injection Flow Instruments Being Removed from Svc.Caused by Personnel Error.Transmitters Were Unisolated & Returned to svc.W/980828 Ltr ML20151S0941998-08-21021 August 1998 Rev 6 to COLR for PVNGS Unit 3 ML20151S0861998-08-21021 August 1998 Rev 4 to COLR for PVNGS Unit 1 ML20151S0901998-08-21021 August 1998 Rev 1 to COLR for PVNGS Unit 2 ML18066A2771998-08-13013 August 1998 Part 21 Rept Re Deficiency in CE Current Screening Methodology for Determining Limiting Fuel Assembly for Detailed PWR thermal-hydraulic Sa.Evaluations Were Performed for Affected Plants to Determine Effect of Deficiency ML17313A5401998-08-13013 August 1998 Special Rept:On 980715,declared PASS Inoperable.Caused by Failure of Offgas Flush/Purge Control Handswitch HS0101. Handswitch Replaced & Post Maintenance Retesting Was Initiated ML17313A5301998-07-31031 July 1998 Monthly Operating Repts for July 1998 for Pvgns,Units 1,2 & 3.W/980812 Ltr ML17313A5201998-07-30030 July 1998 LER 98-004-00:on 980630,personnel Discovered That Pressure Safety Valve Had Not Received Periodic Set Pressure Test for ASME Class 1 Pressure Safety Valve.Caused by Personnel Error.Pressure Safety Valve reviewed.W/980730 Ltr ML17313A5791998-07-0707 July 1998 to PVNGS SG Tube ISI Results for Seventh Refueling Outage Mar & Apr 1998. ML17313A5001998-06-30030 June 1998 Monthly Operating Repts for June 1998 for Palo Verde Nuclear Generating Station,Units 1,2 & 3.W/980710 Ltr ML17313A4671998-06-19019 June 1998 LER 98-007-00:on 980520,CR Personnel Observed Flow & Pressure Perturbations on Chemical & Vol Control Sys Letdown Sys.Caused by Cyclic Fatigue Due to Dynamic Pressure Transients.Unit Letdown Piping Replaced ML17313A4521998-06-19019 June 1998 Rev 5 to COLR for Pvngs,Unit 3. ML17313A4501998-06-19019 June 1998 Rev 4 to COLR for Pvngs,Unit 3. ML17313A4131998-06-0505 June 1998 LER 98-006-00:on 980507,determined That Plant Was Outside Design Basis Due to SI Discharge Check Valve Reverse Flow. Check Valve Was Disassembled,Examined & Reassembled, Whereupon Valve Met Acceptance Criteria ML17313A4211998-05-31031 May 1998 Monthly Operating Repts for May 1998 for Pvngs,Units 1,2 & 3.W/980609 Ltr ML17313A3951998-05-26026 May 1998 LER 98-005-00:on 980428,noted That Required Response Time Testing Had Not Been Performed.Caused by Personnel Error. Coached I&C Personnel Responsible for Reviewing Work Authorization Documentation ML17313A3691998-04-30030 April 1998 Monthly Operating Repts for Apr 1998 for PVNGS.W/980412 Ltr ML17313A3251998-04-0101 April 1998 LER 98-004-00:on 980304,safety Valves as-found Pressures Out of Tolerance.Cause of Event Is Under Investigation.Three Mssv'S & Psv Will Be Replaced W/Refurbished & Recertified Valves During Refueling Outage U1R7 1999-09-30
[Table view] |
Text
REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NBR:9507110110 DOC.DATE: 95/07/06 NOTARIZED: NO DOCKET FACIL:STN-50-529 Palo Verde Nuclear Station, Unit 2, Arizona Publi 05000529 P AUTH. NAME AUTHOR AFFILIATION GRABO,B.A. Arizona Public Service Co. (formerly Arizona Nuclear Power LEVINE,J.M. Arizona Public Service Co. (formerly Arizona Nuclear Power R RECIP.NAME RECIPIENT AFFILIATION
SUBJECT:
LER 95-003-00:on 950613,TS LCO 3.0.3 entered following loss of both trains of essential CW sys & both hydrogen recombiners.Caused by spurious actuations due to broken EDG speed probe connector. Connector replaced.W/950706 ltr.
DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL SIZE:
TITLE: 50.73i50.9 Licensee Event Report (LER), Inciden Rpt, etc.
NOTES:Standardized plant. 05000529 T
RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD4-2 PD 1 1 HOLIAN, B 1 1 TRAN,L 1 1 INTERNAL: ACRS 1 AE+D4S'PD/~B 2 2 AEOD/SPD/RRAB 1 FI LE CEDER> 1 1 NRR/DE/ECGB 1 NRR/DE/EELB 1 1 NRR/DE/EMEB 1 NRR/DISP/PIPB 1 1 D NRR/DOPS/OECB 1 NRR/DRCH/HHFB 1 . 1 NRR/DRCH/HICB 1 NRR/DRCH/HOLB 1 1 NRR/DSSA/SPLB 1 NRR/DSSA/SPSB/B 1 1 NRR/DSSA/SRXB 1 RES/DSIR/EIB 1 1 RGN4 FILE 01 1 EXTERNAL: L ST LOBBY WARD 1 1, LITCO BRYCE,J H 2 2 NOAC MURPHY,G.A 1 1 NOAC POORE,W. 1 1 NRC PDR 1 1 NUDOCS FULL TXT 1 1 NOTE TO ALL "RZDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM OWFN 5D8 (415-2083) TO ELIMINATE YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!
FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 28 ENCL 28
tl Arizona Public Service Company PALO VERDE NUCLEAR GENERATING STATION P.O. BOX 52034 ~ PHOENIX, ARIZONA85072-2034 192-00939-JML/BAG/KR JAMES M. LEVINE July 6, 1995 VICE PREEIDENT NUCLEAR PRODUCTION U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Station P1-37 Washington, DC 20555-0001
Dear Sirs:
Subject:
Palo Verde Nuclear Generating Station (PVNGS)
Unit 2 Docket No. STN 50-529 (License No. NPF-51)
Licensee Event Report 95-003-00 Attached please find Licensee Event Report (LER) 95-003-00 prepared and submitted pursuant to 10CFR50.73. This LER.reports an entry into Technical Specification Limiting Condition for Operation (TS LCO) 3.0.3 following the loss of both trains of essential cooling water system and both hydrogen recombiners.
In accordance with 10CFR50.73(d), a copy of this LER is being forwarded to the Regional Administrator, NRC Region IV. If you have any questions, please contact Burton A. Grabo, Section Leader, Nuclear Regulatory Affairs, at (602) 393-6492.
Sincerely, JML/BAG/KR/pv Attachment cc: L. J. Callan (all with attachment)
K. E. Perkins K. E. Johnston INPO Records Center
'mls (g 9507110110 '7I50706 PDR ADOCK 05000529 8 PDR
I' LICENSEE EVENT REPORT (LE/
CIUTY NAME (1) DOCKET NUMBER (2) PAGE (3)
Palo Verde Unit 2 050005291OF06 (4)
TS 3.0.3 For Loss of Both Trains of Essential Coolin Water and H dro en Recombiners EVENT DATE 8 LER NUMBER 6 REPORT DATE OTHER FACILmES INVOLVED 8 ONTH YEAR SEOUENTIAL REVISION MONTH DAY YEAR NUMBERS NUMBER NUM8ER N/A 0 6 9 5 9 5 - 0 0 3 0 0 0 7 0 6 9 5 NIA IS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR C (Check ona or mora of the following) (11)
MODE (g) 20.402(b) 20.405(c) SO.73(a)(2)rrv) 73.71(b)
POWER 20.45( )O)n 50.38(c)(1) 50.73(a)(2)(v) 73.71(c)
LEVEL(to) $ P P 20.45(s) (1) (ii) 50.38(c)(2) 50.73(a)(2)(vii) OTHER (Specify In Abstract 20.45(a)(1)(iii) 50.73(a)(2)Qi 50.73(a)(2)(vrrr)(A) below and In TerrL NRC Form 20.405(a)(1)(iv) 50.73(a)(2)(ri) 5(L73(a)(2)(vra)(B) 20 45(a)(t)b) 50,73(a)(2)(68 5073(a)(2) 80 UCENSEE CONTACT FOR THIS LER (1 2)
E E NUMBER Burton A. Grabo, Section Leader, Nuclear Regulatory Affairs 6 0 2 3 9 3 - 6 4 9 2 COMPLETE ONE UNE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPOR T(13)
CAUSE MANUFAC- REPORTABLE MANUFAC- REPORTABLE TURER To NPRDS TURER TO NPRDS SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED MONTH DAY YEAR SUBMISSON YES Of yas, complete EXPECTED SUBMISSON DATE) DATE (1 5)
TRACT (Umrt to 1400 spaces, I a., spproximataiy fdtaen angle space typawntten lines) (I 8)
On June 13, 1995, at approximately 1119 MST, Palo Verde Unit 2 was in Mode 1 (POWER OPERATloN), operating at approximately 100 percent power when Control Room personnel entered Technical Specification Limiting Condition for Operation (TS LCO) 3.0.3 following the loss of both trains of essential cooling water system (EW) and both hydrogen recombiners (H2R). Train A EW and supported systems/components were inoperable for preventative maintenance and Train A H2R was inoperable for calibration and functional testing, when the Train B emergency diesel generator (EDG-B) was declared inoperable following spurious actuations of support systems. Since the redundant Train A support system and supported systems/components were inoperable, Train B EW and supported systems/components and Train B H2R were also considered inoperable (cascading TS) and TS LCO 3.0.3 was entered. At approximately 1151 MST, Train A EW was returned to service, and at approximately 1333 MST, Train A H2R was returned to service and TS LCO 3.0.3 was exited.
The cause of the spurious actuations of EDG-B support systems was attributed to a broken EDG speed probe amphenol cable connector. As corrective action, the connector was replaced.
There have been no previous similar events reported pursuant to 10CFR50.73.
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION AQUiYNAME DOCKET NUMBER LER NUMBER PAGE gEAR SEQUENTlAL REVISO NUMBER NUMBER Palo Verde Unit 2 0 5 0 0 0 5 2 9 9 5 - 0 0 3 0 0 0 2 of 0 6
- 1. REPORTING REQUIREMENT:
This LER 529/95-003-00 i,s being written to report a condition prohibited by the plant's Technical Specifications (TS) as specified in 10 CFR 50.73(a)(2)(i)(B).
Specifi.cally, at approximately 1119 MST on June 13, 1995, Palo Verde Unit 2 was in Mode 1 (POWER OPERATION), operating at appzoximately 100 percent power when Control Room personnel (utility, licensed) entered Technical Specification Limiting Condition for Operation (TS LCO) 3.0.3 following the loss of both trains of essential cooling water system (EW) (BI) and both hydrogen recombiners (H2R) (BB). Train A EW and supported systems/components were inoperable for preventative maintenance and Train A H2R was inoperable for calibration and functional testing, when the Train B emergency diesel generator (EDG-B) (EK) was declared inoperable following spurious actuations of support systems. Since the redundant Train A support system and supported systems/components were inoperable, Train B EW and supported systems/components and Train B H2R were also considered inoperable (cascading TS), and TS LCO 3.0.3 was entered.
- 2. EVENT DESCRIPTION:
Prior to the event, at approximately 1002 MST on June 12, 1995, the Train A H2R was declared inoperable for calibration and functional testing and Control Room personnel entered the TS LCO 3.6.4.2 ACTION statement. At approximately 0811 MST on June 13, 1995, the Train A EW pump was declared inoperable for preventative maintenance and Control Room personnel entered TS LCO 3.7.3 ACTION statement. Control Room personnel declared the following EW supported systems/components inoperable and entered the corresponding TS LCO ACTION statements:
Emergency Core Cooling System (ECCS) (BP/BQ), TS LCO 3.5.2; Containment Spray System (CSS) (BE), TS LCO 3.6.2.1; Auxiliary Feedwater System (AFWS) (BA), TS LCO 3.7.1.2; Essential Chilled Water System (EC) (KM), TS LCO 3.7.6; Control Room Essential Filtration System (CREFS) (VI), TS LCO 3.7.7; and Shutdown Cooling System (SDC) (BP), TS LCO 3.7.11.
In accordance with TS LCO 3.7.6 ACTION b, (1.) the normal HVAC system (VZ) was verified to be providing space cooling to the vital power distribution (EJ) rooms that depend on EC for space cooling; (2.) safe shutdown systems
[one train each for boration, pressurizer heaters (AB), and AFWS] which do not depend on the inoperable EC were determined to be operable; and (3.)
all required systems/components that depend on the remaining operable Train B EC for space cooling were determined to be operable.
v 1
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION ACIUlYNAME DOCKET NUMBER LER NUMBER PAGE YEAR SEQUENllAL REwslo NUMBER NUMBER Palo Verde Unit 2 0 5 0 0'0 5 2 9 9 5 - 0 0 3 - 0 0 0 3 of 0 6 At approximately 1119 MST on June 13, 1995, Control Room personnel received several alarms associated with EDG-B. These included an EDG-B status trip alarm, an EDG-B high priority trouble alarm on failure turbo thrust bearing, a Train B load sequencer mode change alarm, and finally an EDG-B low priority trouble alarm on starting air low pressure oz system malfunction. Another EDG-B low priority trouble alarm on )acket water high temperature occurred shortly after the initial alarms. The load sequencer mode change alarm indicated that a normal EDG-B run was in progress. As a result, the sequencer attempted to start selected EDG support equipment, specifically, the EDG-B essential exhaust fan (VJ) and the Train B essential spray pond (ESP) (BS) pump. EDG-B remained in standby condition available to start in emergency mode.
Control Room personnel entered TS LCO 3.8.1.1 ACTION b for one inoperable EDG (EDG-B) and TS LCO 3.3.3.5 for inoperable EDG-B remote shutdown system (IU) monitoring instrumentation channels. Train A EW and supported systems/components and Train A H2R were already inoperable when the Train B emergency diesel generator (EDG-B) was declared inoperable following the spurious actuations. Since the redundant Train A EW and supported systems/components and Train B H2R were inoperable, Train B EW and supported systems/components and Train B H2R were also considered inoperable (cascading TS), and a TS LCO 3.0.3 condition was entered.
At approximately 1151 MST, Train A EW was returned to service without performing the maintenance activities. The following TS LCO ACTION statements were exited: TS LCO 3.5.2 (ECCS), TS LCO 3.6.2.1 (CS), TS LCO 3.7.1.2 ACTION a and b (AFWS), TS LCO 3.7.3 (EW), TS LCO 3.7.6 (EC), TS LCO 3.7. 7 (CREFS), and TS LCO 3. 7. 11 (SDC) . The unit remained in TS LCO 3.0.3 for both trains of H2R inoperable.
At approximately 1217 MST, the TS LCO 3.8.1.1 1-hour ACTION requirement to demonstrate the operability of the remaining AC offsite sources was met.
At approximately 1333 MST, Unit 1 Control Room personnel restored the Train A H2R to service and Unit 2 Control Room personnel exited TS LCOs 3.6.4.2 and 3.0.3.
Troubleshooting was initiated in accordance with an approved work document. During an inspection of the EDG-B speed probe, an amphenol cable connector to flexible conduit was found to be broken. In addition, the bottom part of the amphenol cable connector going to the speed pzobe was found to be loose. The broken amphenol cable connector resulted in erroneous signals to be input to the EDG engine speed sensing control.
The speed sensing control reacted to the erroneous speed probe input signal and output a "NORMAL EDG RUN" signal to the load sequencer that EDG-B had reached greater than 280 zpm.'he load sequencer output
LICENSE EVENT REPORT (LER) TEXT CO INUATION AC!UlYNAME DOCKET NUMBER LER NUMBER PAGE YEAR SEOVENllAL . RENSO NUMBER NUMBER Palo Verde Unit 2 0 5 0 0 0 5 2 9 9 5 - 0 0 3 - 0 0 0 4Cf0 6 electrical start signals to the EDG-B essential exhaust fan and the Train B ESP pump. The speed sensing control output signal also released interlocks in the EDG control circuitry which resulted in the high and low priority trouble alarms in the Control Room because EDG-B was not actually running at the time. The damaged speed probe amphenol cable connector was replaced and the connection going to the speed probe was tightened undez the direction of an approved work document.
At approximately 0145 MST on June 14, 1995, Control Room personnel declared EDG-B operable and exited TS LCO 3.8.1.1 ACTION b and TS LCO 3,3.3.5 following the satisfactory completion of the EDG-B surveillance requirement. At approximately 0830 MST, the surveillance requirement for EDG-A to verify operability was satisfactorily completed.
- 3. ASSESSMENT OF THE SAFETY CONSEQUENCES AND THE IMPLICATIONS OF THIS EVENT:
With the exception of the Train A H2R, the Train A EW and supported systems/components were restored to service within approximately 32 minutes. The preventative maintenance work on the Train A EW pump had not begun; only the power supply was removed. EDG-B remained in standby condition available to start in emergency mode. No conditions were found during troubleshooting that would have prevented the EDG from performing its intended safety function for emergency mode operations. The EDG engine controls have redundant speed sensing controls and only one probe is required to perform the required functions needed to support the EDG functions during emergency operations NUREG 1432, "Standard Technical Specifications Combustion Engineering Plants," April 1995, LCO 3.8.1 ACTION B would have allowed for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> prior to declaring the required features supported by the inoperable EDG inoperable when its redundant required feature(s) is inoperable. This ACTION is intended to provide assurance that a loss of offsite power during the period that an EDG is inoperable, does not result in a complete loss of safety function of redundant required features. 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> from the discovery of these events existing concurrently is acceptable because it minimizes the risk while allowing time for restoration before subjecting the unit to transients associated with shutdown. The remaining OPERABLE EDG and offsite circuits are adequate to supply electrical power to onsite Class lE power distribution systems. Thus, on a component basis, single failure protection for the required feature's function may have been lost; however, function has not been lost. The 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> completion time takes into account the OPERABILITY of the redundant counterpart to the inoperable required feature. Additionally, the 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> completion time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repair, and the low probability of a design
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION ACIU1Y NAME DOCKET NUMBER LER NUMBER PAGE YEAR sEOUENBAL REVISIO NUMBER NUMBER Palo Verde Unit 2 0 5 0 0 0 5 2 9 9 5 - 0 0 3 - 0 0 05of 0 6 basis accident occurring during this period. The Train A syst: em and components were only inoperable for approximately 32 minutes. Therefore, there were no adverse safety consequences or implications as a result of this event. The event did not result in any challenges to the fission product barriers oz result in any releases of radioactive materials. This event did not adversely affect the safe operation of the plant or the health and safety of the public.
CAUSE OF THE EVENT:
The TS LCO 3.0.3 entries were attributed to required redundant equipment being inoperable on Train A when EDG-B was declared inoperable following the spurious actuations of the EDG-B essential exhaust fan and the Train B ESP pump.
An independent investigation of this event was conducted in accordance with the APS Corrective Action Program. As part of the investigation, a root cause of failure analysis of the broken amphenol cable connection will be performed by APS Engineering personnel. The amphenol cable connector is currently protected by a steel step platform. The flexible cable leading to the connection is partially exposed and unprotected if personnel miss the steel step platform. The connector was most likely damaged by stepping off of the protective steel platform onto the flexible cable. A preliminary evaluation has determined that the apparent failure mechanism is attributed to inattention to detail during maintenance, operations, or engineering activities (SALP Cause Code A: Personnel Error). Zf the evaluation results differ from this determination, a supplement to this report will be submitted to describe the final root cause of failure.
No unusual characteristics of the work location (e.g., noise, heat , poor lighting) directly contributed to this event. There were no procedural errors which contributed to this event.
STRUCTURE~ SYSTEMS OR COMPONENT INFORMATION The broken amphenol cable connector, which was discovered during troubleshooting, rendered the EDG-B engine speed probe inoperable. EDG-B was declared inoperable at approximately 1119 MST on June 13, 1995 following the spurious actuations of the EDG-B essential exhaust fan and the Train B ESP pump. EDG-B was returned to service at approximately 0145 MST on June 14, 1995. EDG-B was out of service for approximately 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> and 26 minutes.
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION ACIUTYNAME DOCKET NUMBER LER NUMBER PAGE yEAR SEOUEMlAL REVELS NUMBER NUMBER Palo Verde Unit 2 0 5 0 0'0 5 2 9 9 5 - 0 0 3 - 0 0 0 6of0 6 Other than the spurious actuation of the EDG-B essential exhaust fan and the Train B ESP pump, there were no other safety system responses and none were necessary. No failures of components with multiple functions were involved.
The amphenol cable connector is supplied by Cooper Energy Services. The model number is MS3108A-10SL-4S.
- 6. CORRECTIVE ACTIONS TO PREVENT RECURRENCE:
The remaining speed probes in all three units were visually inspected and no anomalies were found.
No corrective actions to prevent recurrence have been identified. The amphenol cable connection is currently protected by a steel step platform.
Although the flexible cable leading to the connection is partially exposed and unprotected if personnel miss the steel step platform, since Unit 2 commercial operation began in September 1986, no similar failure has occurred in Unit 2 causing the speed probe to be inoperable. A search of work history has identified two times in Unit 3 (EDG-B) when broken amphenol cable connectors had been replaced (August 1987 and October 1992). However, these events in Unit 3 did not result in erroneous signals 'to be input to the EDG engine speed sensing control and subsequent spurious actuations of support systems. The investigation determined that a design modification providing additional protection was not warranted.
7 ~ PREVIOUS SIMILAR EVENTS:
There have been no previous similar events reported pursuant to 10CFR50.73 in the last three years.
1