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Category:LICENSEE EVENT REPORT (SEE ALSO AO
MONTHYEARML17355A3891999-07-20020 July 1999 LER 99-001-00:on 990623,manual Rt from 100% Power Following Multiple Control Rod Drops Was Noted.Caused by Manual Action Taken by Reactor Control Operator.Inspected & Repaired Stationary Gripper Regulating Cards.With 990720 Ltr ML17354B1921998-11-18018 November 1998 LER 98-007-00:on 981020,containment Purge Supply,Valve Opened Wider than TS Limit.Caused by Improper Setting of Mechanical Stops.Incorporated Improved Standard Method of Measuring Angular Valve Position Into Sp.With 981118 Ltr ML17354B1361998-10-16016 October 1998 LER 98-004-00:on 980921,automatic Reactor Trip Occurred. Caused by Inadequate re-correlation of Intermediate Range Neutron Flux Instrumentation Reactor Trip Bistable. Enhanced Applicable Plant Procedures.With 981016 Ltr ML17354B0341998-07-15015 July 1998 LER 98-003-00:on 980619,discovered That Auxiliary Feedwater Sys Was Inoperable Due to Inadequate Inservice Testing of Valves.Caused by Misunderstanding of Testing Criteria.Util Revised Procedures & Verified Operability of Valves ML17354A9841998-06-18018 June 1998 LER 97-007-01:on 970730,automatic Reactor Trip Occurred Due to Closure of B Msiv.Caused by Failed BFD22S Relay.Six Relays on 3A,3B & 3C MSIVs Were Replaced & Implemented Plant Change to Disable Electronic Trip Function on 3 AFW Pumps ML17354A9741998-06-0909 June 1998 LER 98-002-00:on 980513,discovered Potential LOCA-initiated Electrical Fault Which Places ECCS Outside Design Basis. Caused by Inadequate Review of Effect on non-safety Circuit failures.Re-powered PC-*-600A Relays ML17354A8511998-03-24024 March 1998 LER 97-009-01:on 971114,discovered That CR Console Switch for 3B Sgfp Was Not in Start Position.Caused by Inadequate Procedural Guidance.Revised Procedures 3/4-OP-074,informed Personnel of Event & Performed Walkdown of CR ML17354A8441998-03-18018 March 1998 LER 98-001-00:on 980216,manual Reactor Trip Occurred Due to Loss of Turbine Control Oil Pressure W/Steam Leak in Auxiliary Feedwater Steam Supply Piping.Auxiliary Governor Maint Instructions Will Be revised.W/980318 Ltr ML17354A7361997-12-12012 December 1997 LER 97-009-01:on 971114,identified That CR Console Switch for 3B SG Feedwater Pump Was Not in Start Position.Caused by Inadequate Procedural Guidance.Procedures 3/4-OP-074,SGFP Were revised.W/971212 Ltr ML17354A6801997-10-0808 October 1997 LER 97-008-00:on 970909,containment Sump Debris Screens Outside Design Basis Due to Stress Damage Was Discovered. Caused by Inadequate Procedural Guidance & Personnel Error. Discrepancies Found on Screens corrected.W/971008 Ltr ML17354A6121997-08-29029 August 1997 LER 97-007-00:on 970730,automatic Reactor Trip Occurred. Caused by Closure of B Main Steam Isolation Valve.Failed W Relay & Equivalent Relays Were replaced.W/970829 Ltr ML17354A6081997-08-18018 August 1997 LER 97-006-00:on 970722,manual Reactor Trip Occurred Due to Failed Rod Control Power Supplies.Replaced Twelve Power Supplies in Rod Control Logic & Power cabinets.W/970818 Ltr ML17354A5801997-07-14014 July 1997 LER 97-005-00:on 970618,RCP Oil Collection Sys Was Found Outside Design Basis.Caused Because Design Did Not Consider Component Parts to Be Potential Leakage Sources.Entire RCP Oil Collection Sys Was reviewed.W/970714 Ltr ML17354A5141997-05-22022 May 1997 LER 97-002-00:on 970423,automatic Reactor Tripped.Caused by Actuation of Turbine Overspeed Protection Circuit. Administrative Procedures Governing Inadequate Work Controls Will Be Revised to Capture Lessons learned.W/970522 Ltr ML17354A5061997-05-0909 May 1997 LER 97-003-00:on 970410,mode Changed W/O Meeting Requirements of TS 3.0.4 Due to Inadequate Procedural Guidance.Night Order Was Issued to Inform Personnel That S/G Blowdown Keylock Switches Were Left in drain.W/970509 Ltr ML17354A5051997-05-0909 May 1997 LER 97-004-00:on 970411,auxiliary Feedwater Automatic Start Upon Trip of All Main Feedwater Pumps,Occurred.Caused by Mispositioned Valve Closing.Valves Listed as Inappropriately Positioned Were repositioned.W/970509 Ltr ML17354A4781997-04-25025 April 1997 LER 97-001-00:on 970327,ECCS Recirculation Loop Leakage Was Found to Be in Condition Outside Design Basis Due to Gasket Movement During Installation During Spring 1966 Reassembly. Gasket Replaced & Pump tested.W/970425 Ltr ML17354A4581997-03-28028 March 1997 LER 97-002-00:on 970303,manual Reactor Trip Following Rod Control Urgent Failure Alarm Occurred.Caused by Phase Failure Detection on Stationary a Circuits of 2BD Rod Control Cabinet.Air Conditioning replaced.W/970328 Ltr ML17354A4511997-03-26026 March 1997 LER 97-001-00:on 970118,missed Surveillance on CR Position Verification Occurred Due to Inoperable Rod Deviation Monitor.Faulty Circuit Common Connection Was Corrected & Rdm Operability Was restored.W/970326 Ltr ML17354A4061997-02-0303 February 1997 LER 96-004-03:on 970107,identified Three Instances of Inadequate Surveillance Testing.Caused by Inadequate Surveillance Procedures.Surveillance Procedures Revised ML17354A3771996-12-27027 December 1996 LER 96-012-00:on 961204,determined Containment Average Temp Being Determined Based on Only Two Temp Elements Instead of Three as Required by Tss.Caused by Log Only Requiring One Entry.Log revised.W/961227 Ltr ML17354A3261996-11-0606 November 1996 LER 96-011-00:on 961009,potential for Overpressurizing Post Accident Containment Vent Filter Housings Occurred.Caused by Improper Change Mgt.Monitoring Sys Operating Procedures revised.W/961106 Ltr ML17354A3071996-10-22022 October 1996 LER 96-010-00:on 960924,manual Reactor Shutdown Occurred. Caused by Failed Rod Control Sys Regulation Card in 2AC Power cabinet.2AC Power Cabinet DC Power Supplies,Cabling & Connectors checked.W/961022 Ltr ML17353A8711996-08-27027 August 1996 LER 96-009-00:on 960729,failed to Reflect Heavy Load Design Info in Procedural Controls.Caused by Failure to Incorporate 1982 Procedure Changes.Suspended Lifting of Heavy Loads & Took Turbine Bldg Crane OOS.W/960827 Ltr ML17353A7411996-06-18018 June 1996 LER 96-008-00:on 960521,surveillance Method for Testing Emergency Diesel Generators (EDG) Determined Inadequate. Caused by Personnel Error.All Four EDGs Rapid Start Tested & EDG Surveillance Procedures modified.W/960618 Ltr ML17353A7401996-06-18018 June 1996 LER 96-004-02:on 960524,identified Inadequate Surveillance Testing.Caused by Inadequate Surveillance Procedures.Entered Tech Spec Statements,Tested Required Instruments Functions & Revised Plant procedure.W/960618 Ltr ML17353A6901996-05-13013 May 1996 LER 96-004-01:on 960220,identified Potential Tech Spec non-compliance Associated W/Surveillance Testing of AFW Actuation Circuitry on Sg.Caused by Inadequate Surveillance Procedures.Procedures revised.W/960513 Ltr ML17353A6741996-05-0606 May 1996 LER 96-001-00:on 960409,manual Rt Occurred Due to Turbine Governer Control Oil Perturbation.Disassembled & Inspected Governor Valve for Cleanliness & Corrosion products.W/960506 Ltr ML17353A6651996-04-29029 April 1996 LER 96-007-00:on 960329,inadvertent ESF Actuation Occurred During Refueling Outage Due to Cognitive Personnel Error. Personnel Involved Counseled & Integrated Safeguards Test Procedures Being revised.W/960429 Ltr ML17353A6601996-04-25025 April 1996 LER 96-006-00:on 960327,manual Rt Occurred Due to 3C Transformer Lockout & Loss of 3B SG Mfp.Replaced SAM Timer Relay in 3AC16.W/960425 Ltr ML17353A6491996-04-23023 April 1996 LER 96-005-00:on 960326,certain Safety Injection Accumulator Filled Evolutions Resulted in cross-tied Configuration.C/A: Night Order Written & Operations Procedure 3/4-OP-064 revised.W/960423 Ltr ML17353A6051996-03-18018 March 1996 LER 96-003-00:on 960222,two Arpi Inoperable & TS 3.0.3 Entered.Proposed License Amend Submitted to Revise Allowed Misalignment from +/-12 Steps to =/-18 Steps Between Arpi & Dpi at Less than 90% power.W/960318 Ltr ML17353A6041996-03-18018 March 1996 LER 96-004-00:on 960220,surveillance Testing of AFW Actuation Circuitry Was Inadequate.Caused by Inadequate Surveillance Procedures.Tested Untested Portions of Actuation Logic for AFW Automatic Start signal.W/960318 Ltr ML17353A5861996-03-0606 March 1996 LER 96-002-00:on 960209,automatic Turbine Trip/Rt Occurred Due to High SG Level.Caused by Personnel Error.Replaced Both Hinge Pins on B Sgfp Discharge Check valve.W/960306 Ltr ML17353A5761996-03-0101 March 1996 LER 96-001-00:on 960131,intake CWS Flow Rates Found W/ Potential to Be Less than Required by Design Basis.Caused by Influx of Aquatic Grass & Algae Onto Basket Strainers of Icw Flow Path.Mechanically Cleaned strainers.W/960301 Ltr ML17353A4451995-11-0909 November 1995 LER 95-007-00:on 951017,manual Rt Occurred Following Drop of Four Control Rods.Caused by Water Intrusion Into Rod Control Power Cabinet 2BD.Inspected Control Power Cabinet 2BD for Other Water damage.W/951109 Ltr ML17353A4241995-10-12012 October 1995 LER 95-006-00:on 950913,analysis Showed That CCW Exchangers Susceptible to Damage Due to flow-induced Vibration.Ccw Sys Has Been Flow Balanced to Closer tolerances.W/951012 Ltr ML17353A3601995-09-13013 September 1995 LER 95-005-00:on 950818,containment Pressure Testing Procedure Resulted in Inhibiting Both Trains of Containment Pressure from Initiated Esf.Revised Procedure to Require Testing of Each Train separately.W/950913 Ltr ML17353A2951995-07-17017 July 1995 LER 94-005-02:on 941103,both Units Outside Design Basis Due to Design Defect in Safeguards Bus Sequencer Test Logic. Resumed Monthly Manual Testing of Sequencer ML17352B1581995-05-0505 May 1995 LER 95-004-00:on 950407,unit Being Shutdown to Investigate Recurring non-urgent Failure Alarms from Redundant Rod Control Power Supplies.Reactor Manually Tripped.All Four PS-3 Power Supplies replaced.W/950505 Ltr ML17352B1181995-04-0707 April 1995 LER 95-003-00:on 950309,intake Cooling Water Flow Rate Through CCW Heat Exchangers Fell Below Assumed Design Basis. Caused by an Influx of Aquatic Grass & Algae Onto Basket Strainers.Strainers cleaned.W/950407 Ltr ML17352B0701995-03-13013 March 1995 LER 95-002-00:on 950215,inadequate Definition of Loops Filled Resulted in Units in Condition Prohibited by Ts. Issued TS Position Statement to Define Term Loops Filled as Used in TS 6.4.1.1.4.W/950313 Ltr ML17352B0321995-02-0909 February 1995 LER 94-005-01:on 941103,design Defect Found in Safeguards Bus Sequencer Test Logic,Placing Facility Outside Design Basis.Design Mods to Eliminate Software Logic Problems Will Be Implemented During Next Refueling outages.W/950209 Ltr ML17352B0101995-01-20020 January 1995 LER 94-006-00:on 941226,C Main Feedwater Control Valve Failed Closed,Causing Reactor & Turbine Trips.Caused by Loose Screw Terminal Connection.I/P Transducers Replaced W/ New Model W/Different Design Wire connection.W/950120 Ltr ML17352A9511994-12-13013 December 1994 LER 94-006-00:on 941130,Unit 4 Tripped Automatically.Caused by Failure of Flexible Link Connection Between Main Generator B Phase Bus & Associated Isolated Phase Bus Bar. All Bolts on Flexible Link checked.W/941213 Ltr ML17352A8871994-11-10010 November 1994 LER 94-005-00:on 941103,design Defect in Safeguards Bus Sequencer Test Logic Places Both Units Outside Design Basis. Caused by 3A Sequencer Failed to Respond as Expected to Opposite Unit SI signal.W/941110 Ltr ML17352A8851994-11-10010 November 1994 LER 94-004-00:on 941103,Unit 3 Outside Design Basis Due to Two of Three Required Safety Injection Pumps Inoperable. Control Switches for 3A & 3B Safety Injection Pumps Immediately Returned to automatic.W/941110 Ltr ML17352A8421994-10-21021 October 1994 LER 94-004-00:on 940923,Unit 4 Tripped Automatically from Rated Power.Caused by Faulty Regulator Transistor.Faulty Backup Power Supply Replaced & Maint History for Power Supplies reviewed.W/941021 Ltr ML17352A8431994-10-20020 October 1994 LER 94-005-00:on 940924,Unit 4 Manually Tripped.Caused by Manual Actuation.Light Bulb & Socket replaced.W/941020 Ltr ML17352B1671994-08-16016 August 1994 LER 94-003-00:on 940720 & 21,util Discovered That Several Required Valve Stroke Time Surveillances Had Not Been Performed.Caused by Personnel Error.Personnel Reassigned & Procedures and Surveillance Tracking Software Enhanced 1999-07-20
[Table view] Category:RO)
MONTHYEARML17355A3891999-07-20020 July 1999 LER 99-001-00:on 990623,manual Rt from 100% Power Following Multiple Control Rod Drops Was Noted.Caused by Manual Action Taken by Reactor Control Operator.Inspected & Repaired Stationary Gripper Regulating Cards.With 990720 Ltr ML17354B1921998-11-18018 November 1998 LER 98-007-00:on 981020,containment Purge Supply,Valve Opened Wider than TS Limit.Caused by Improper Setting of Mechanical Stops.Incorporated Improved Standard Method of Measuring Angular Valve Position Into Sp.With 981118 Ltr ML17354B1361998-10-16016 October 1998 LER 98-004-00:on 980921,automatic Reactor Trip Occurred. Caused by Inadequate re-correlation of Intermediate Range Neutron Flux Instrumentation Reactor Trip Bistable. Enhanced Applicable Plant Procedures.With 981016 Ltr ML17354B0341998-07-15015 July 1998 LER 98-003-00:on 980619,discovered That Auxiliary Feedwater Sys Was Inoperable Due to Inadequate Inservice Testing of Valves.Caused by Misunderstanding of Testing Criteria.Util Revised Procedures & Verified Operability of Valves ML17354A9841998-06-18018 June 1998 LER 97-007-01:on 970730,automatic Reactor Trip Occurred Due to Closure of B Msiv.Caused by Failed BFD22S Relay.Six Relays on 3A,3B & 3C MSIVs Were Replaced & Implemented Plant Change to Disable Electronic Trip Function on 3 AFW Pumps ML17354A9741998-06-0909 June 1998 LER 98-002-00:on 980513,discovered Potential LOCA-initiated Electrical Fault Which Places ECCS Outside Design Basis. Caused by Inadequate Review of Effect on non-safety Circuit failures.Re-powered PC-*-600A Relays ML17354A8511998-03-24024 March 1998 LER 97-009-01:on 971114,discovered That CR Console Switch for 3B Sgfp Was Not in Start Position.Caused by Inadequate Procedural Guidance.Revised Procedures 3/4-OP-074,informed Personnel of Event & Performed Walkdown of CR ML17354A8441998-03-18018 March 1998 LER 98-001-00:on 980216,manual Reactor Trip Occurred Due to Loss of Turbine Control Oil Pressure W/Steam Leak in Auxiliary Feedwater Steam Supply Piping.Auxiliary Governor Maint Instructions Will Be revised.W/980318 Ltr ML17354A7361997-12-12012 December 1997 LER 97-009-01:on 971114,identified That CR Console Switch for 3B SG Feedwater Pump Was Not in Start Position.Caused by Inadequate Procedural Guidance.Procedures 3/4-OP-074,SGFP Were revised.W/971212 Ltr ML17354A6801997-10-0808 October 1997 LER 97-008-00:on 970909,containment Sump Debris Screens Outside Design Basis Due to Stress Damage Was Discovered. Caused by Inadequate Procedural Guidance & Personnel Error. Discrepancies Found on Screens corrected.W/971008 Ltr ML17354A6121997-08-29029 August 1997 LER 97-007-00:on 970730,automatic Reactor Trip Occurred. Caused by Closure of B Main Steam Isolation Valve.Failed W Relay & Equivalent Relays Were replaced.W/970829 Ltr ML17354A6081997-08-18018 August 1997 LER 97-006-00:on 970722,manual Reactor Trip Occurred Due to Failed Rod Control Power Supplies.Replaced Twelve Power Supplies in Rod Control Logic & Power cabinets.W/970818 Ltr ML17354A5801997-07-14014 July 1997 LER 97-005-00:on 970618,RCP Oil Collection Sys Was Found Outside Design Basis.Caused Because Design Did Not Consider Component Parts to Be Potential Leakage Sources.Entire RCP Oil Collection Sys Was reviewed.W/970714 Ltr ML17354A5141997-05-22022 May 1997 LER 97-002-00:on 970423,automatic Reactor Tripped.Caused by Actuation of Turbine Overspeed Protection Circuit. Administrative Procedures Governing Inadequate Work Controls Will Be Revised to Capture Lessons learned.W/970522 Ltr ML17354A5061997-05-0909 May 1997 LER 97-003-00:on 970410,mode Changed W/O Meeting Requirements of TS 3.0.4 Due to Inadequate Procedural Guidance.Night Order Was Issued to Inform Personnel That S/G Blowdown Keylock Switches Were Left in drain.W/970509 Ltr ML17354A5051997-05-0909 May 1997 LER 97-004-00:on 970411,auxiliary Feedwater Automatic Start Upon Trip of All Main Feedwater Pumps,Occurred.Caused by Mispositioned Valve Closing.Valves Listed as Inappropriately Positioned Were repositioned.W/970509 Ltr ML17354A4781997-04-25025 April 1997 LER 97-001-00:on 970327,ECCS Recirculation Loop Leakage Was Found to Be in Condition Outside Design Basis Due to Gasket Movement During Installation During Spring 1966 Reassembly. Gasket Replaced & Pump tested.W/970425 Ltr ML17354A4581997-03-28028 March 1997 LER 97-002-00:on 970303,manual Reactor Trip Following Rod Control Urgent Failure Alarm Occurred.Caused by Phase Failure Detection on Stationary a Circuits of 2BD Rod Control Cabinet.Air Conditioning replaced.W/970328 Ltr ML17354A4511997-03-26026 March 1997 LER 97-001-00:on 970118,missed Surveillance on CR Position Verification Occurred Due to Inoperable Rod Deviation Monitor.Faulty Circuit Common Connection Was Corrected & Rdm Operability Was restored.W/970326 Ltr ML17354A4061997-02-0303 February 1997 LER 96-004-03:on 970107,identified Three Instances of Inadequate Surveillance Testing.Caused by Inadequate Surveillance Procedures.Surveillance Procedures Revised ML17354A3771996-12-27027 December 1996 LER 96-012-00:on 961204,determined Containment Average Temp Being Determined Based on Only Two Temp Elements Instead of Three as Required by Tss.Caused by Log Only Requiring One Entry.Log revised.W/961227 Ltr ML17354A3261996-11-0606 November 1996 LER 96-011-00:on 961009,potential for Overpressurizing Post Accident Containment Vent Filter Housings Occurred.Caused by Improper Change Mgt.Monitoring Sys Operating Procedures revised.W/961106 Ltr ML17354A3071996-10-22022 October 1996 LER 96-010-00:on 960924,manual Reactor Shutdown Occurred. Caused by Failed Rod Control Sys Regulation Card in 2AC Power cabinet.2AC Power Cabinet DC Power Supplies,Cabling & Connectors checked.W/961022 Ltr ML17353A8711996-08-27027 August 1996 LER 96-009-00:on 960729,failed to Reflect Heavy Load Design Info in Procedural Controls.Caused by Failure to Incorporate 1982 Procedure Changes.Suspended Lifting of Heavy Loads & Took Turbine Bldg Crane OOS.W/960827 Ltr ML17353A7411996-06-18018 June 1996 LER 96-008-00:on 960521,surveillance Method for Testing Emergency Diesel Generators (EDG) Determined Inadequate. Caused by Personnel Error.All Four EDGs Rapid Start Tested & EDG Surveillance Procedures modified.W/960618 Ltr ML17353A7401996-06-18018 June 1996 LER 96-004-02:on 960524,identified Inadequate Surveillance Testing.Caused by Inadequate Surveillance Procedures.Entered Tech Spec Statements,Tested Required Instruments Functions & Revised Plant procedure.W/960618 Ltr ML17353A6901996-05-13013 May 1996 LER 96-004-01:on 960220,identified Potential Tech Spec non-compliance Associated W/Surveillance Testing of AFW Actuation Circuitry on Sg.Caused by Inadequate Surveillance Procedures.Procedures revised.W/960513 Ltr ML17353A6741996-05-0606 May 1996 LER 96-001-00:on 960409,manual Rt Occurred Due to Turbine Governer Control Oil Perturbation.Disassembled & Inspected Governor Valve for Cleanliness & Corrosion products.W/960506 Ltr ML17353A6651996-04-29029 April 1996 LER 96-007-00:on 960329,inadvertent ESF Actuation Occurred During Refueling Outage Due to Cognitive Personnel Error. Personnel Involved Counseled & Integrated Safeguards Test Procedures Being revised.W/960429 Ltr ML17353A6601996-04-25025 April 1996 LER 96-006-00:on 960327,manual Rt Occurred Due to 3C Transformer Lockout & Loss of 3B SG Mfp.Replaced SAM Timer Relay in 3AC16.W/960425 Ltr ML17353A6491996-04-23023 April 1996 LER 96-005-00:on 960326,certain Safety Injection Accumulator Filled Evolutions Resulted in cross-tied Configuration.C/A: Night Order Written & Operations Procedure 3/4-OP-064 revised.W/960423 Ltr ML17353A6051996-03-18018 March 1996 LER 96-003-00:on 960222,two Arpi Inoperable & TS 3.0.3 Entered.Proposed License Amend Submitted to Revise Allowed Misalignment from +/-12 Steps to =/-18 Steps Between Arpi & Dpi at Less than 90% power.W/960318 Ltr ML17353A6041996-03-18018 March 1996 LER 96-004-00:on 960220,surveillance Testing of AFW Actuation Circuitry Was Inadequate.Caused by Inadequate Surveillance Procedures.Tested Untested Portions of Actuation Logic for AFW Automatic Start signal.W/960318 Ltr ML17353A5861996-03-0606 March 1996 LER 96-002-00:on 960209,automatic Turbine Trip/Rt Occurred Due to High SG Level.Caused by Personnel Error.Replaced Both Hinge Pins on B Sgfp Discharge Check valve.W/960306 Ltr ML17353A5761996-03-0101 March 1996 LER 96-001-00:on 960131,intake CWS Flow Rates Found W/ Potential to Be Less than Required by Design Basis.Caused by Influx of Aquatic Grass & Algae Onto Basket Strainers of Icw Flow Path.Mechanically Cleaned strainers.W/960301 Ltr ML17353A4451995-11-0909 November 1995 LER 95-007-00:on 951017,manual Rt Occurred Following Drop of Four Control Rods.Caused by Water Intrusion Into Rod Control Power Cabinet 2BD.Inspected Control Power Cabinet 2BD for Other Water damage.W/951109 Ltr ML17353A4241995-10-12012 October 1995 LER 95-006-00:on 950913,analysis Showed That CCW Exchangers Susceptible to Damage Due to flow-induced Vibration.Ccw Sys Has Been Flow Balanced to Closer tolerances.W/951012 Ltr ML17353A3601995-09-13013 September 1995 LER 95-005-00:on 950818,containment Pressure Testing Procedure Resulted in Inhibiting Both Trains of Containment Pressure from Initiated Esf.Revised Procedure to Require Testing of Each Train separately.W/950913 Ltr ML17353A2951995-07-17017 July 1995 LER 94-005-02:on 941103,both Units Outside Design Basis Due to Design Defect in Safeguards Bus Sequencer Test Logic. Resumed Monthly Manual Testing of Sequencer ML17352B1581995-05-0505 May 1995 LER 95-004-00:on 950407,unit Being Shutdown to Investigate Recurring non-urgent Failure Alarms from Redundant Rod Control Power Supplies.Reactor Manually Tripped.All Four PS-3 Power Supplies replaced.W/950505 Ltr ML17352B1181995-04-0707 April 1995 LER 95-003-00:on 950309,intake Cooling Water Flow Rate Through CCW Heat Exchangers Fell Below Assumed Design Basis. Caused by an Influx of Aquatic Grass & Algae Onto Basket Strainers.Strainers cleaned.W/950407 Ltr ML17352B0701995-03-13013 March 1995 LER 95-002-00:on 950215,inadequate Definition of Loops Filled Resulted in Units in Condition Prohibited by Ts. Issued TS Position Statement to Define Term Loops Filled as Used in TS 6.4.1.1.4.W/950313 Ltr ML17352B0321995-02-0909 February 1995 LER 94-005-01:on 941103,design Defect Found in Safeguards Bus Sequencer Test Logic,Placing Facility Outside Design Basis.Design Mods to Eliminate Software Logic Problems Will Be Implemented During Next Refueling outages.W/950209 Ltr ML17352B0101995-01-20020 January 1995 LER 94-006-00:on 941226,C Main Feedwater Control Valve Failed Closed,Causing Reactor & Turbine Trips.Caused by Loose Screw Terminal Connection.I/P Transducers Replaced W/ New Model W/Different Design Wire connection.W/950120 Ltr ML17352A9511994-12-13013 December 1994 LER 94-006-00:on 941130,Unit 4 Tripped Automatically.Caused by Failure of Flexible Link Connection Between Main Generator B Phase Bus & Associated Isolated Phase Bus Bar. All Bolts on Flexible Link checked.W/941213 Ltr ML17352A8871994-11-10010 November 1994 LER 94-005-00:on 941103,design Defect in Safeguards Bus Sequencer Test Logic Places Both Units Outside Design Basis. Caused by 3A Sequencer Failed to Respond as Expected to Opposite Unit SI signal.W/941110 Ltr ML17352A8851994-11-10010 November 1994 LER 94-004-00:on 941103,Unit 3 Outside Design Basis Due to Two of Three Required Safety Injection Pumps Inoperable. Control Switches for 3A & 3B Safety Injection Pumps Immediately Returned to automatic.W/941110 Ltr ML17352A8421994-10-21021 October 1994 LER 94-004-00:on 940923,Unit 4 Tripped Automatically from Rated Power.Caused by Faulty Regulator Transistor.Faulty Backup Power Supply Replaced & Maint History for Power Supplies reviewed.W/941021 Ltr ML17352A8431994-10-20020 October 1994 LER 94-005-00:on 940924,Unit 4 Manually Tripped.Caused by Manual Actuation.Light Bulb & Socket replaced.W/941020 Ltr ML17352B1671994-08-16016 August 1994 LER 94-003-00:on 940720 & 21,util Discovered That Several Required Valve Stroke Time Surveillances Had Not Been Performed.Caused by Personnel Error.Personnel Reassigned & Procedures and Surveillance Tracking Software Enhanced 1999-07-20
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217L9371999-10-20020 October 1999 Safety Evaluation Supporting Licensee Proposed Alternative from Certain Requirements of ASME Code,Section XI for First 10-Yr Interval Request for Relief for Containment Inservice Insp Program ML17355A4471999-09-30030 September 1999 Monthly Operating Repts for Sept 1999 for Turkey Point,Units 3 & 4.With 991008 Ltr ML17355A4121999-08-31031 August 1999 Monthly Operating Repts for Aug 1999 for Turkey Point,Units 3 & 4.With 990909 Ltr ML17355A3981999-07-31031 July 1999 Monthly Operating Repts for July 1999 for Turkey Point,Units 3 & 4.With 990809 Ltr ML17355A3891999-07-20020 July 1999 LER 99-001-00:on 990623,manual Rt from 100% Power Following Multiple Control Rod Drops Was Noted.Caused by Manual Action Taken by Reactor Control Operator.Inspected & Repaired Stationary Gripper Regulating Cards.With 990720 Ltr ML17355A3841999-06-30030 June 1999 Monthly Operating Repts for June 1999 for Turkey Point,Units 3 & 4.With 990713 Ltr ML17355A3681999-06-30030 June 1999 Revised Update to Topical QA Rept, Dtd June 1999 ML17355A3611999-06-30030 June 1999 Refueling Outage ISI Rept. ML17355A3511999-05-31031 May 1999 Monthly Operating Repts for May 1999 for Turkey Point,Units 3 & 4.With 990609 Ltr ML17355A3331999-04-30030 April 1999 Monthly Operating Repts for Apr 1999 for Turkey Point,Units 3 & 4.With 990511 Ltr ML20217B9871999-04-0808 April 1999 Changes,Tests & Experiments Made as Allowed by 10CFR50.59 for Period Covering 971014-990408 ML17355A2881999-04-0505 April 1999 COLR for Turkey Point Unit 4 Cycle 18. ML17355A2911999-03-31031 March 1999 Monthly Operating Repts for Mar 1999 for Turkey Point,Units 3 & 4.With 990414 Ltr ML17355A2551999-02-28028 February 1999 Monthly Operating Repts for Feb 1999 for Turkey Point Nuclear Power Plant,Units 3 & 4.With 990315 Ltr ML17355A2261999-01-31031 January 1999 Monthly Operating Repts for Jan 1999 for Turkey Point,Units 3 & 4.With 990211 Ltr ML17355A2201999-01-20020 January 1999 Refueling Outage ISI Rept. ML17355A1911998-12-31031 December 1998 Monthly Operating Repts for Dec 1998 for Turkey Point,Units 3 & 4.With 990112 Ltr ML18008A0461998-11-30030 November 1998 Monthly Operating Repts for Nov 1998 for Turkey Point,Units 3 & 4.With 981209 Ltr ML17354B1921998-11-18018 November 1998 LER 98-007-00:on 981020,containment Purge Supply,Valve Opened Wider than TS Limit.Caused by Improper Setting of Mechanical Stops.Incorporated Improved Standard Method of Measuring Angular Valve Position Into Sp.With 981118 Ltr ML17354B1891998-11-0909 November 1998 Simulatory Certification Update 2. ML17354B1901998-10-31031 October 1998 Monthly Operating Repts for Oct 1998 for Turkey Point,Units 3 & 4.With 981112 Ltr ML17354B1591998-10-23023 October 1998 COLR for Turkey Point Unit 3 Cycle 17. ML17354B1361998-10-16016 October 1998 LER 98-004-00:on 980921,automatic Reactor Trip Occurred. Caused by Inadequate re-correlation of Intermediate Range Neutron Flux Instrumentation Reactor Trip Bistable. Enhanced Applicable Plant Procedures.With 981016 Ltr ML17354B1311998-09-30030 September 1998 Monthly Operating Repts for Sept 1998 for Turkey Point Unit 3 & 4.With 981012 Ltr ML17354B0971998-09-0909 September 1998 Part 21 Rept Re Possible Machining Defect in Certain One Inch Stainless Steel Swagelok Front Ferrules,Part Number SS-1613-1.Caused by Tubing Slipping Out of Fitting at Three Times Working Pressure of Tubing.Notified Affected Utils ML17354B0981998-08-31031 August 1998 Monthly Operating Repts for Aug 1998 for Turkey Points,Units 3 & 4.With 980915 Ltr ML17354B0771998-07-31031 July 1998 Monthly Operating Repts for July 1998 for Turkey Point,Units 3 & 4.W/980810 Ltr ML17354B0341998-07-15015 July 1998 LER 98-003-00:on 980619,discovered That Auxiliary Feedwater Sys Was Inoperable Due to Inadequate Inservice Testing of Valves.Caused by Misunderstanding of Testing Criteria.Util Revised Procedures & Verified Operability of Valves ML17354B0241998-06-30030 June 1998 Monthly Operating Repts for June 1998 for Turkey Point,Units 3 & 4.W/980709 Ltr ML17354B0171998-06-29029 June 1998 Rev 1 to PTN-FPER-97-013, Evaluation of Turbine Lube Oil Fire. ML17354A9841998-06-18018 June 1998 LER 97-007-01:on 970730,automatic Reactor Trip Occurred Due to Closure of B Msiv.Caused by Failed BFD22S Relay.Six Relays on 3A,3B & 3C MSIVs Were Replaced & Implemented Plant Change to Disable Electronic Trip Function on 3 AFW Pumps ML17354A9741998-06-0909 June 1998 LER 98-002-00:on 980513,discovered Potential LOCA-initiated Electrical Fault Which Places ECCS Outside Design Basis. Caused by Inadequate Review of Effect on non-safety Circuit failures.Re-powered PC-*-600A Relays ML20248F7441998-05-31031 May 1998 Reactor Vessel Working Group,Response to RAI Regarding Reactor Pressure Vessel Integrity ML17354A9711998-05-31031 May 1998 Monthly Operating Repts for Turkey Point,Units 3 & 4. W/980611 Ltr ML17354A9231998-04-30030 April 1998 Monthly Operating Repts for Apr 1998 for Turkey Point,Units 3 & 4.W/980511 Ltr ML17354A8821998-03-31031 March 1998 Monthly Operating Repts for Mar 1998 for Turkey Point,Units 3 & 4.W/980409 Ltr ML17354A8511998-03-24024 March 1998 LER 97-009-01:on 971114,discovered That CR Console Switch for 3B Sgfp Was Not in Start Position.Caused by Inadequate Procedural Guidance.Revised Procedures 3/4-OP-074,informed Personnel of Event & Performed Walkdown of CR ML17354B0001998-03-18018 March 1998 Florida Power & Light Topical Quality Asurance Rept, Dtd June 1998 ML17354A8441998-03-18018 March 1998 LER 98-001-00:on 980216,manual Reactor Trip Occurred Due to Loss of Turbine Control Oil Pressure W/Steam Leak in Auxiliary Feedwater Steam Supply Piping.Auxiliary Governor Maint Instructions Will Be revised.W/980318 Ltr ML17354A8311998-02-28028 February 1998 Monthly Operating Repts for Feb 1998 for Turkey Point,Units 3 & 4.W/980311 Ltr ML17354A7871998-01-31031 January 1998 Monthly Operating Repts for Jan 1998 for Turkey Point,Units 3 & 4.W/980209 Ltr ML17354A7581997-12-31031 December 1997 Monthly Operating Repts for Dec 1997 for Turkey Point,Unit 3 & 4.W/980112 Ltr ML17354A7361997-12-12012 December 1997 LER 97-009-01:on 971114,identified That CR Console Switch for 3B SG Feedwater Pump Was Not in Start Position.Caused by Inadequate Procedural Guidance.Procedures 3/4-OP-074,SGFP Were revised.W/971212 Ltr ML17354A7381997-11-30030 November 1997 Monthly Operating Repts for Nov 1997 for Turkey Point,Units 3 & 4.W/971215 Ltr ML17354A7211997-10-31031 October 1997 Monthly Operating Repts for Oct 1997 for Turkey Point,Units 3 & 4.W/971114 Ltr ML17354A7491997-10-13013 October 1997 SG Insp Rept. ML17354A8851997-10-13013 October 1997 FPL Units 3 & 4 Changes,Tests & Experiments Made as Allowed by 10CFR50.59 for Period Covering 960408-971013. ML17354A6801997-10-0808 October 1997 LER 97-008-00:on 970909,containment Sump Debris Screens Outside Design Basis Due to Stress Damage Was Discovered. Caused by Inadequate Procedural Guidance & Personnel Error. Discrepancies Found on Screens corrected.W/971008 Ltr ML17354A6791997-10-0606 October 1997 COLR Unit 4 Cycle 17, for Turkey Point ML17354A6811997-09-30030 September 1997 Monthly Operating Repts for Sept 1997 for Turkey Point,Units 3 & 4.W/971009 Ltr 1999-09-30
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CATEGORY 1 REGULATOmZ INFORMATION DISTRIBUTION b STEM (RIDE)
I ACCESSION NRR:9604300164 DOC.DATE: 96/04/25 NOTARIZED: NO DOCKET g FACIL:50-250 Turkey Point Plant, Unit 3, Florida Power and Light C 05000250 AUTH. NAME AUTHOR AFFILIATION HANEKFO.I. Florida Power S Light Co.
HOVEYFR.J. Florida Power & Light Co.
RECIP.NAME RECIPIENT AFFILIATION
SUBJECT:
LER 96-006-00:on 960327,manual RT occurred due to 3C transformer lockout a loss of 3B SG MFP.Replaced SAM timer relay in 3AC16.W/960425 ltr.
DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR L ENCL ( SIZE:
TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.
NOTES:
RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-1 PD 1 1 CROTEAU,R 1 1 INTERNAL: ALODSPD/RAB 2 2 AEOD/SPD/RRAB 1 1 FILE CENTE~R~ 1 1 NRR/DE/ECGB 1 1 RR/DE/EELB 1 1 NRR/DE/EMEB 1 1 NRR/DRCH/HHFB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 1 NRR/DRCH/HQMB 1 1 NRR/DRPM/PECB 1 1 NRR/DSSA/SPLB 1 1 NRR/DSSA/SRXB 1 1 RES/DSIR/EIB 1 1 RGN2 FILE 01 . 1 1 D
EXTERNAL: L ST LOBBY WARD 1 1 LITCO BRYCEFJ H 2 2 NOAC MURPHYFG.A 1 1 NOAC POOREFW. 1 1 NRC PDR 1 1 NUDOCS FULL TXT 1 1 N
NOTE TO ALL "RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM OWFN 5D-5(EXT. 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 25 ENCL 25
FPL APR 25 1996 L-96-98 10 CFR 550.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Gentlemen:
Re: Turkey Point Unit 3 Docket No. 50-250 Reportable Event: 96-006-00 Manual Reactor Trip Due to =3C Transformer Lockout and Loss of The attached Licensee Event Report, 250/96-006-00, is being provided in accordance with 10 CFR 50.73(a) (2) (iv) .
If there are any questions, please contact us.
Very truly yours, R. J. Hovey Vice Presiden Turkey Point Plant OIH attachment cc: Stewart D. Ebneter, Regional Administrator, Region USNRC II, Thomas P. Johnson, Senior Resident Inspector, USNRC, Turkey Point Plant 30004i 9604300i64 960425 PDR ADOCK 05000250 S
an FPL Group company PDR
/gp '
LICENSEE EVENT REPORT LER FACILITY NAME <I) DOCKET NUMBER 2 PACE 9 TURKEY POINT UNIT 3 05000250 1 OF 6 TITLE <6) MANUAL REACTOR TRIP DUE TO 3C TRANSFORMER LOCKOUT AND LOSS OF 3B "STEAM GENERATOR MAIN FEEDWATER PUMP RVFNT DATE 5 LER NUMSRR 6 RPT DATE 7 OTHER FACILITIRS INV. 8 MON DAY YR YR SE 6 MON DAY YR FACILITY NAMES DOCKET 6 S 03 27 96 96 006 00 04 25 96 OPERATING MODE )9)
PONRR LEVEL {10) 100 LICENSEE CONTACT FOR THIS LER (12)
Tele hone Number O. I. Hanek, Licensing Engineer 305 246-6607 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT 13 CAUSR SYSTFA COMPONENT MANUFAC'TURFR NPRDS? CAUSE SYSTEM COMPONENT MANUFACTURER NPRDS7 SUPPLEMENTAL REPORT EXPECTED )14) NO YES 0 EXPECTED SUBMISSION DATE )15)
DAY
)II yee, cceylete EXPECTED SUBMISSION DATE)
ABSTRACT {16)
On March 27, 1996, Florida Power & Light Company's (FPL) Turkey Point Unit 3 was operating in Mode 1 at 100% and Unit 4 was in a refueling outage. The 4C transformer and 4C 4160 volt bus were out of service for planned maintenance.
At 1715 while performing the 4C transformer lockout trip test of 3AC01 breaker, the 3C transformer locked out resulting in a trip of the 3B steam generator feedwater pump (SGFP) . Since an automatic turbine runback was not observed, a manual turbine runback was initiated and a manual reactor trip was performed due to decreasing steam generator levels. All control rods fully inserted into the core and all the rod position indication rod bottom lights turned on after the reactor trip.
The cause of the 3C transformer lockout was mechanically induced vibration experienced after opening the 3ACOl breaker which resulted in inadvertent actuation of the GE Model 12SAM11B21A (SAM) timer relay. The failure to obtain the expected automatic turbine runback was due to a closed zoot valve to pressure switch PS 1604-1 which senses first stage turbine pressure, which prevented the initiation of the automatic turbine runback.
The NRC Operations Center was notified at 1816 on March 27, 1996 in accordance with 10 CFR 50.72(b) (2)(ii), Reactor Protection System Actuation and Engineered Safety Feature Actuation.
FACILITY NAME DOCKET NUNBER LER NOMBER PAGE NO.
TURKEY POINT UNIT 3 05000250 96-006-00 2 OF 6 On March 27, 1996, FPL's Turkey 'Point Unit 3 was operating in Mode 1 at 100%
and Unit 4 was in a refueling outage. The 4C transformer and 4C 4160 volt bus [EA:BU] were out of service for planned maintenance.
Turkey Point Unit 4 was performing the 4C transformer lockout [EA:86] trip test of 3AC01 breaker [EA:BKR]. The supply breaker (3AC01) from the 4C transformer [EA:XFMR] to the 3C 4160 volt bus was out of its assigned cubicle with an umbilical cord connected for test operation and was situated approximately one foot from the SAM timer relay [EA:2]. The trip and close fuses [EI:FU] for 3ACOl,were installed. The 3C 4160 volt bus was being supplied from the 3C transformer using breaker 3AC16. In the cable spreading room, the 4C transformer lockout relay was tripped with the test blades open. The blade was closed to test the lockout trip of 3AC01, At 1745, when breaker 3AC01 opened, mechanically induced vibration resulted in inadvertent actuation of the SAM timer relay. The 3C transformer lockout actuated, and the normal bus supply breaker 3AC16 opened to deenergize the 3C 4160 volt bus, which is the normal power supply foz the 3B steam generator feedwatez pump (SGFP) [SJ:P]. Therefore, this caused a loss of the 3B SGFP. The plant did not run back to 60't as expected. Since an automatic turbine runback was not observed, a manual turbine runback was initiated. A manual reactor trip was performed 59 seconds into the event due to decreasing steam generator levels. The Auxiliary Feedwater System (AFW) [BA] automatically actuated on steam generator Low-Low level. All control rods fully inserted into the core and all the rod position indication rod bottom lights turned on after the reactor trip.
Unit 3 was stabilized in Mode 3 (Hot Standby) with decay heat being exhausted to the main condenser. Unit 3 was returned to service on March 29, 1996.
The C buses are non-safety related buses. Normally, the 4C transformer feeds the 4160 volt 4C bus through breaker 4AC16. The 4C transformer is the alternate supply to the 3C bus through breaker 3AC01. The 3C transformer is similarly configured, normally supplying the 3C 4160 volt 3C bus through breaker 3AC16. The 3C transformer is the alternate supply to the 4C "4160 volt bus through breaker 4AC01.
The 4C transformer and 4C 4160 volt bus were out of service for planned maintenance. Turkey Point Unit 4 was performing the 4C transformez lockout trip test of 3ACOl breaker. The supply breaker (3AC01) from the 4C transformer to the 3C 4160 volt bus was out of its assigned cubicle with an umbilical cord connected for test operation. During this test configuration, the supply breaker 3AC01 was situated in the walkway of the switchgear zoom diagonally in front of cubicles 3AC15 and 3AC16. The SAM timer relay is mounted on the door of cubicle 3AC15. The 3AC01 breaker was situated approximately one foot from the SAM timer relay. When breaker 3AC01 opened in response to the 4C transformer lockout trip test, a subsequent 3C transformer lockout was actuated, and the normal bus supply breaker 3AC16 opened to deenergize the 3C 4160 volt bus.
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LICENSEE EVENT REPORT (LER) TEXT CONT
~ INUATION FACILITY NAME DOCKET NUMBER LER NUMBER PAGE NO.
TURKEY POINT UNIT 3 05000250 ,
96-006-00 3OF6 There aze seven control paths that will lead to the 3C transformer lockout:
1-3. 3 Bus transformer differential relays 187/3CBT (one per phase) 4, 3C transformer feeder fault relay 3AC16/3CBTX-FT (SAM timer relay)
- 5. Transformer fault pressure relay 3C260/163X-SFP Transformer ground fault relay 64/3CBT
- 7. 4C bus breaker failure relay 4AC01/3CBTY-FT Of these seven trip paths that could have led to a transformer lockout, only
.5 the 3CBX-FT (SAM timer relay) in the 3AC15 cubicle had a target after the lockout occurred.
In order for this relay to electrically actuate, both the overcurrent fault protection relay 3AC16/150-.3CBTX relay and the ground fault relay 3AC16/3CBTX-GF relay must actuate. The ground fault relay can only electrically actuate in two scenarios: either the overcurrent relays for 3AC16 must actuate or the blocking diode, 3AC16/97, must fail. Since there were no targets observed after the trip on the overcurrent relays and the current at the time of the trip was about 1000 amps (3200 amps required for trip), the overcurrent relays did not actuate. In order for the ground fault relay to electrically actuate, the diode must have failed. However, failure of the diode in itself is not sufficient to cause the ground fault relay to actuate. In addition, the ovezcurrent fault protection relay (150-3CBTX) must also actuate, either electrically or by vibration. This relay also had no targets after the trip. Since there were no targets indicating that the overcurrent fault protection relay or the ground fault relay actuated, either electrically oz by vibration, this scenario was eliminated.
A similar scenario was investigated which would allow electrical actuation of the 3CBTX-FT relay if both the overcurrent fault protection relay and the ground fault relay are mechanically actuated simultaneously due to vibration. Since these relays are mounted in cubicles 3AC16 and 3AC15 respectively, actuation by vibration is plausible. However, since no target was found on the ovezcurrent fault protection relay after the trip occurred, this scenario was eliminated.
l The final scenario investigated was the vibration of the 3CBTX-FT relay contacts causing the 3C transformer lockout relay (186/3CBT) to actuate.
This scenario requires no additional equipment failures to take place and leaves a target on the SAM timer (3CBTX-FT) relay. The investigation showed that the actuation of the SAM relay occurred while cycling the 3AC01 breaker near the cubicle 3AC15 door. Actuation of the SAM timer relay was also verified to occur by mechanically agitating the switchgear cubicle floor without any actuation of the 3AC01 breaker.
Based on the above investigation, the root cause of the event was determined to be mechanically induced vibration caused by the opening of the breaker 3AC01 which resulted in an inadveztent actuation of the 3C SAM timer relay which caused a 3C transformer lockout. The 3C transformer lockout opened the normal bus supply breaker 3AC16 which deenergized the 3C 4160 volt bus.
This caused a loss of the 3B SGFP.
t LICENSEE EVENT REPORT t
(LER) TEXT CONTINUATION FACILITY NAME DOCKET NUMBER LER NUMBER PAGE NO.
TURKEY POINT UNIT 3 05000250 96-006-00 4 OF 6 Inspection of the SAM timer relay revealed that the gap associated with the SAM timer relay contacts was 0.178 millimeters for the set of contacts in use,as compared to 0.332 millimeters for an unused set of contacts. The reduced gap between the SAM timer relay contacts increased the probability of inadvertent actuation of the relay when subjected to mechanical vibrations.
- 2. During the course of the zoot cause investigation, tripping of the SAM timer relay 3CBTX/FT was replicated by agitating the floor plate directly in front of the 3AC15 cubicle. The steel floor plates inside of the 4160 volt 3C bus enclosure were found to be loose. The four, floor plates in front of the breaker cubicles 3AC01, 3AC02, 3AC15 and 3AC16 were found not to be attached at a few places to structural steel members installed below, allowing transmission of vibration through the floor.
After welding of the floor plates in front of the breaker cubicles 3AC01, 3AC02, 3AC15, and 3AC16 was completed," the agitation test was repeated and the SAM timer relay 3CBTX/FT did not txip.
An automatic tuzbine runback due to the loss of the 3B SGFP did not occur.
The zoot valve to PS-3-1604-1 [SB, 63] which senses first stage turbine pressure was closed, preventing operation of a relay contact which would initiate the turbine runback. A manual turbine runback was initiated by the reactor operator. An investigation was performed to determine the last time the root valve to PS-3-1604-1 was manipulated. Plant records show that the turbine runback system calibration was performed in September, 1995, during the last Unit 3 refueling outage. The system calibration documentation" reflects that the root valve to PS-3-1604-1 was left in the open position.
The Updated Final Safety Analysis Report analysis assumes a loss of feedwater to all steam generators due to the loss of the feedwater pumps or valve malfunction. In the March 27 .event, feedwater flow was not lost completely, but was reduced to 50% of normal flow, and the expected automatic turbine runback due to loss of a feedwater pump did not occur. A manual turbine runback was initiated by the reactor operator. All steam genezatoxs were affected by the reduction in feedwater flow. In the analysis, the reactor trip is expected to occur due to a Low-Low Level in any steam generator oz Steam/Feedwater Flow Mismatch Coincident with Low Level in any steam generator. In this event neither trip occurred due to operator actions which manually tripped the reactor prior to reaching the steam genezatox Low-Low Level setpoint or the Steam/Feedwater Flow Mismatch Coincident with Low Level setpoint in any steam generator. The analysis does not credit turbine runback as a result of the loss of a feedwater pump or valve malfunction. The analysis shows that following a loss of feedwater, AFW is capable of removing the stored and residual heat, thus preventing either overpressurization of the reactor coolant system or loss of water from the reactor core. The analysis also assumes only one AFW pump is available due to a single active failure. In this event the AFW system automatically actuated on steam generator Low-Low level and all three AFW pumps were available following the reactor trip, therefore, the plant's response was bounded by the analysis. Therefore, this event did not
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION
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FACILITY NAME DOCKET NUMBER LER NUMBER PAGE NO.
TURKEY POINT UNIT 3 05000250 96-006-00 5OF6 compromise the health or safety of plant personnel oz the general public.
This event is reportable under the requirements'of 10 CFR 50.73(a)(2) (iv) .
- 1. The SAM timer relay in 3AC16 was replaced.
- 2. The SAM timer relay in 4AC01 was inspected and replaced.
- 3. The root valve to PS-3-1604-1 was opened.
- 4. The root valve to PS-3-1604-1 was last manipulated during pressure switch calibration in September 1995. This incident predates a similar incident in November 1995 for which corrective actions included extensive training of personnel on procedural requirements for independent verification and self-checking. The individual who performed the last system calibration was counseled.
- 5. A walkdown was performed of the secondary side systems for both Units 3 and 4 to verify valve positions. No other discrepancies were found.
- 6. A walkdown was performed of the primary side systems for Unit 4. No other discrepancies were found.
- 7. Loose floor steel plates in front of the breaker cubicles 3AC01, 3AC02, 3AC15 and 3AC16 inside the 4160 volt 3C bus enclosure were secured by welding to reduce vibration transmission. The balance, of the floor steel plates inside the 4160 volt 3C bus enclosure will be inspected and secured by welding as needed during the next Unit 3 .
refueling outage.
- 8. All floor steel plates inside the 4160 volt 4C bus enclosure were inspected and secured by welding as needed to reduce vibration transmission.
- 9. Additional administrative controls foz work in the C 4160 volt buses for both units were established to reduce the probability of vibration induced actuations.
- 10. The Unit 3 SAM timer relay wiring was modified to a double contact configuration to minimize susceptibility to vibration induced actuation.
- 1. FPL will determine if any other modifications are needed to improve the 3/4 C bus reliability.
LXCENSEE EVENT REPORT (LER) TEXT CONTINUATXON FACILITY NAME DOCKET NUMBER LER NUMBER PAGE NO.
TURKEY POINT UNIT 3 05000250 96-006-00 6OF6 A. Similar Events: LER 251/94-004 discusses a similar event with the 4C bus lockout caused by the jarring of a differential relay due to an interference between a breaker cubicle door and the wall of, the switchgear room.
B. EIIS Codes are shown in the format [EIIS SYSTEM: IEEE component function identifier, second component identifier (if appropriate)].