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 RelaysML17354A974 |
Person / Time |
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Site: |
Turkey Point |
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Issue date: |
06/09/1998 |
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From: |
Mowrey C FLORIDA POWER & LIGHT CO. |
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To: |
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Shared Package |
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ML17354A973 |
List: |
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References |
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LER-98-002-02, LER-98-2-2, NUDOCS 9806160124 |
Download: ML17354A974 (12) |
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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
[Table view] |
Text
LICENSEE EVENT REPORT (LER)
DOCKET NUMBER (2) PAGE 3)
FACILITY NAHE (1)
TURKEY POINT UNITS 3 & 4 05000250 OF TITLE (4) Potential LOCA-Initiat:ed Electrical Fault Places ECCS Outside Design Basis EVENT DATE (5) LER NUMBER(6) RPT DATE (7) OTHER FACILITIES INV. (B)
MON DAY YR YR RI MON DAY FACILITY NAMES DOCKET 4 (S) 98 98 00 98 Turkey Point Unit 4 05000251 OPERATING MODE (9)
PONER LEVEL (10) 40/100 LICENSEE CONTACT FOR THIS LER (12)
Telephone Number C.L. MOWREY, COMPLIANCE SPECIALIST (305) 246-6204 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)
CAUSE SYSTEM MANUFACTURER EPIX2 CAUSE SYSTEM COMPONENT EPIX2 EXPECTED MONTH SUPPLEMENTAL REPORT EXPECTED (14) = NO YES Cl SUBMISSION DATE (15)
(ii yes, cmrplete EXPECTED SUBMISSION DATE)
ABSTRACT (16)
During a design review of the 120 volt AC instrument busses, Florida Power &
Light Company discovered that faults associated with instrument panel 3(4)P06 .
could result in opening of a vital instrument bus breaker causing loss of power to pressure control auxiliary relay PC-*-600X. A loss of "B" power to this relay would prevent Emergency Core Cooling System (ECCS) train valve MOV-*-863B from being opened using existing procedures. This valve is required to be opened post-accident to permit emergency sump recirculation in the "piggy-back" mode of operation, in which a Residual Heat Removal pump pzovides suction boost to the Safety Injection and/or the Containment Spray pumps. The redundant ECCS train "A" pressure controller relay PC-*-601X is properly designed. If, in addition to the mechanistic failure of MOV-*-863B described herein, a single failure of MOV-
- -863A is assumed, emergency recirculation in piggy-back mode will be lost, with the potential for inadequate core cooling. This is a condition outside the design basis of the plant.
The cause of this condition was inadequate review of the effect of non-safety circuit failures on safety related equipment, when the PC-*-600X/601X relays were repowezed in 1984.
The PC-*-600X relays have been repowered.from a safety related power supply.
Turkey Point is evaluating separation and breaker/fuse coordination for other equipment powered from the 120 VAC instrument panels.
9806160124 980609 PDR ADOCK 050002SO S PDR
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION FACILITY NAME DOCKET NUMBER LER NUMBER PAGE NO.
TURKEY POINT UNIT 3 05000250 98-002-00 2OF7 I. DESCRIPTION OF THE EVENT While performing an evaluation of separation and breaker/fuse coordination for equipment powered from the safety related 120 VAC instrument panels [EF:pl], Turkey Point's Design Engineering Group identified a safety concern related to the separation and coordination of power provided to safety related pressure control auxiliary relay PC-*-600X [BP:68] supplied for each nuclear unit (PC-3-600X for Unit 3, and PC-4-600X for Unit 4). This relay provides a pressure inte'rlock to prevent opening of train "B" safety related motor operated valve MOV-*-863B [BP:isv] in the event of high Residual Heat Removal (RHR) system operating pressure. A loss of power to this relay would prevent the opening of MOV-"-863B when required for the recirculation phase of a Loss-of-Coolant Accident (LOCA). Power to the redundant train "A" pressure controller relay PC-*-601X, which interlocks train "A" valve MOV-*-863A, is properly designed.
For the Emergency Core Cooling System, Turkey Point's Updated Final Safety Analysis Report (UFSAR) states in Section 6.2:
"Redundancy and segregation of instrumentation and components is incorporated to assure that postulated malfunctions will not impair the ability of the system to meet the design objectives. The system is effective in the event of loss of normal plant auxiliary power coincident with the loss of coolant, and can accommodate the failure of any single component or instrument channel to respond actively in the system."
A single failure is a single active failure of a component. A component or device that fails as a consequence of the initiating event is not considered a single failure.
The safety injection [BQ] and RHR [BP] systems provide adequate emergency core cooling following a LOCA. Adequate injection is initially provided through use of accumulators and injection of water from the Refueling Water Storage Tank (RWST)
[BP:tk] using the High Head Safety Injection pumps (HHSI)(high pressure injection)
[BQ:p] and RHR pumps (low pressure, high volume injection) (BP:p]. When the RWST is depleted, sufficient water from spilled coolant and safety injection is available on the floor of containment such that suction for the emergency core cooling pumps can be transferred to the. reactor containment recirculation sumps [NH; rvz], i.e., the floor of containment. In recirculation, the RHR pump takes suction from the containment sumps and provides flow to the suction of the HHSI and Containment Spray (CS) [BE] pumps as required ("piggy-back" operation), which includes a flow path through MOV-*-863A and/or MOV-*-863B.
In the process of transfexxing to containment recirculation, numerous motor operated valves are realigned using plant procedure EOP-ES-1.3, "Transfer to Cold Leg Recirculation." Prior to full depletion of the RWST, the RHR loop is isolated from the RWST by stopping the RHR pumps, isolating the suction valves to the RHR pumps
,(MOVs-*-862A and 862B) and opening the recirculation sump isolation valves (MOVs-*-
860A and B, and MOVs-"-861A and B). When sufficient water is available in the containment recirculation sump, the RHR,pumps are restarted in recirculation mode back to the care. Operation in the piggy-back mode (an RHR pump providing suction boost to the HHSI and/or CS pumps), is required when continued containment spray operation is needed long term and/or when Reactor Coolant System (RCS) [AB] pressure remains above RHR shutoff head. If piggy-back operation is required, RHR recirculation back to the core is isolated (close MOVs-*-744A and B). During this time, a HHSI pump and a CS pump continue to take suction from the RWST. When the
~ )
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION FACILITY NAME DOCKET NUMBER LER NUMBER PAGE NO.
TURKEY POINT UNIT 3 05000250 98-002-00 3 OF 7 RWST is depleted, the HHSI and CS pumps are stopped and the RWST is isolated (close MOVs-*-864A and B). Then the recirculation isolation valves from the RHR to SI pumps are opened (MOV-*-863A and B) and a HHSI and CS pump are restarted.
The 120V Instrument AC System has four sets of equipment for each unit, each set consisting of a 7.5 kVA,'125V DC/120V AC inverter, distribution panel, static transfer switch and an associated constant voltage transformer (CVT) for alternate 120V AC supplied from a vital Motor Control Center. Each inverter is normally
, powered by a separate bus of the vital DC system.
Technical Specification 3/4.5.2, "ECCS Subsystems T,~ Greater than or Equal to 350 Degrees F, " provides the requirements for ECCS operation at power. This specification requires the operability of four HHSI pumps, two RHR pumps, two RHR heat exchangers, an operable flow path from the RWST, and two operable flow paths from the containment recirculation sump. With a required ECCS component (other than a HHSI pump) or flow path inoperable, the inoperable component or flow path must be restored within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or the affected unit placed in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in HOT SHUTDOWN in the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
The design basis of the safety injection system is, in part, to provide adequate core cooling for the injection and recirculation phases of a LOCA, considering a Loss-of-offsite Power (LOOP) and a concurrent single active failure. As a result of the, accumulation of water on the floor of containment fr'om a LOCA, certain non-safety related components are expected to become submerged, potentially causing a fault that would open vital AC panel breaker 3(4) P06-10, with the consequence that power is lost to PC-*-600X. A simplified wiring diagram is included with this report to aid in understanding the issue. Loss of power to this pressure control auxiliary relay will have the consequence that MOV-"-863B cannot be opened by an operator using existing procedures to permit containment sump recirculation in piggy-back mode. If, in addition to the mechanistic failure of MOV-*-863B described herein, a single failure of MOV-*-863A is assumed, emergency recirculation in piggy-back mode would be lost, with the potential for inadequate core cooling. This condition is outside the plant's design basis, and reportable in accordance with 10 CFR 50.72(b)(ii)(B). This concern was reported on May 13, 1998
'I.
CAUSE OF THE EVENT The cause of this event was cognitive personnel error, in 1984, on the part of utility non-licensed personnel. Pressure control auxiliary relays PC-*-600X and PC-
"-601X were repowered in 1984 in response to a design deficiency discovered at that time (and reported in LER 250/84-18). During the design process to repower the relays, it is apparent that the design engineer was not aware that non-safety instruments were also powered from 3(4) P06-10. At the time these devices were repowered, certain design tools, such as a vital AC load list and the Total Equipment Database-were not available to engineering personnel. These enhanced configuration control documents would have significantly reduced the potential for this design error. Plant actions were taken in the mid to late 1980s to improve the quality and usability of design information as part of the Performance Enhancement Program (PEP).
i(
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION FACILITY NAME DOCKET NUMBER LER NUMBER PAGE NO.
TURKEY POINT UNIT 3 05000250 98-002-00 4OF7 III. ANALYSIS OF THE EVENT Pressure control relay PC-*-600X is powered from breaker 3(4)P06-10 on safety related 120 volt AC instrument bus 3(4) P06. The 120 VAC vital instrument busses are powered from inverters [EF:invt] which are backed by the plant safety related batteries
[EJ:btry]. Because of specific issues related to instrument panel operation when powered from inverters, the instrument busses use high speed, magnetic only, breakers to prevent an instrument fault from tripping the instrument bus.
The condition reported herein involves a specific set of devices powered from vital instrument breaker 3(4) P06-10 (a 10 amp high speed breaker) . These are shown on the attached simplified diagram (page 7). Each of these devices was evaluated, and only the loss of PC-*-600X resulted in a reportable condition.
In the event of a LOCA, the containment recirculation sump will fill with water as the RWST is depleted: The LOCA may submerge the Reactor Coolant Drain Tank (RCDT) instrumentation powered from 3(4) P06-10 and would expose all of the non-safety related instruments inside containment to environmental conditions for which they have not been qualified. The submergence or environmental conditions affecting these non-safety related, non-qualified devices would be expected to result in a fault that would open 3(4) P06-10.
When less than 155, 000 gallons are available in the RWST, the operator would transition to EOP-ES-1.3, "Transfer to Cold Leg Recirculation." As stated above, the RHR pumps aze initially placed in the recirculation mode when sufficient water is available in the sump. A decision is then made whether to directly inject using the RHR pumps or to operate in the piggy-back mode of operation to permit operation of the SI and/oz CS pumps. Based on analysis, the expected conclusion for small (less than 2 inch diameter) to large break, events is that piggy-back operation is required.
The expected decision point at Step 17 of EOP-ES-1.3 is to go to piggy-back operation. Given the condition described herein, at Step 22, while realigning MOVs-
- -863A and B, MOV-*-863B would not open due to loss of power to PC-*-600X. With an assumed single failure of MOV-*-863A or its power supply, piggy-back operation cannot be established without additional, non-proceduralized actions. Following the Response Not Obtained (RNO) in Step 22, the operator would reopen MOVs-*-744A and B to permit cold leg injection from the RHR pumps directly into the RCS. Depending on RCS pressure, however, this RNO step may not provide any flow to the RCS.
For large and intermediate break LOCAs, the result of the significant depzessurization that occurs due to the break size is that recirculation will be available using the RHR pumps for direct injection into the RCS. Therefore, adequate core cooling can be maintained.
For small breaks analyzed in the UFSAR (2, 3, and 4 inch breaks), RCS pressure remains above 200 psig until the transient was terminated. This pressure is greater than the shutoff head of the RHR pumps, precluding direct injection.
Because the small break LOCA analyses in. the UFSAR terminate before transfer to recirculation is expected to occur, an assessment of plant response to several small break events was performed using the plant simulator. A break of approximately 2.3 inch diameter was run assuming a loss-of-offsite power (LOOP) with a single failure of an Emergency Diesel Generator (EDG)[EK:dg]. This break was chosen because it is one of the smallest break sizes for which containment spray would be expected to actuate, and thus would result in a relatively rapid drain down of the RWST (drain down in about 2.25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br />), a high decay heat at transfer to recirculation, and would likely require piggy-back operation due to high RCS pressure. This break was, found
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION FACILITY NAME DOCKET NUMBER LER NUMBER PAGE NO.
TURKEY POINT UNIT 3 05000250 98-002-00 5 OF 7 to result in sufficient RCS depressurization to allow direct injection into the RCS using the RHR pumps without piggy-back operation.
A smaller break of approximately I inch diameter was also run on the simulator assuming LOOP and an EDG failure. This break was selected because containment spray would not be expected to actuate. With no containment spray, between 6 and 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> would be required to drain the RWST to the point that transfer to cold leg recirculation would be required. For these very small breaks, accumulator injection may not occur. After the initial break and blowdown, the HHSI pumps would be able to maintain RCS pressure at a reasonably high level. Following an initial temperature soak on the RCS, a cooldown using the atmospheric steam dumps would be performed.
is expected that RCS subcooling would also be restored as a result of this cooldown.
It Following cooldown, the pressurizer would be refilled by opening the Power Operated Relief Valves (PORVs)[AB:rv). Based on simulator operation, RHR entry conditions would be reached following cooldown and depressurization within two to three hours, with most of the RWST volume still available. At this time operators would place the unit in a normal RHR alignment, with HHSI and charging used as required to maintain pressurizer level. If normal RHR can not be aligned for some reason, transfer to cold leg recirculation could be performed when the RWST is drained (6 to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> into the transient). Direct recirculation through MOVs-*-744A and B would be expected to result in 400 g.p.m. flow or greater into the RCS. The PORVs could also be used in this case to permit additional RCS depressurization to support cold leg recirculation using the RHR pumps.
The inability to go into the piggy-back mode of operation potentially affects t'e containment response to a loss of coolant accident. Inability to provide containment spray is most significant for a larger sized LOCA where greater containment pressurization occurs. Containment pressure and temperature peak very early in the accident and have already started to decrease when the transfer point to cold leg recirculation is reached. Previous analyses performed for FPL demonstrate that containment spray is secured at 30 minutes after a LOCA, two emergency containment if coolers are capable of maintaining containment temperature and pressure below the peak found in the analysis. While only one emergency containment cooler is assumed to automatically start, a second cooler would be manually started by operator action prior to transfer to cold leg recirculation. The loss of containment spray for containment cooling represents a long term environmental qualification concern.
would therefore be acceptable to restore spray within several days and avoid It environmental qualification concerns'ased on the preceding analysis, loss of the piggy-back mode of operation would not impact the ability to provide either adequate core cooling or adequate containment heat removal. Additionally, actions would have been possible after a LOCA to identify and correct the concern, and restore piggy-back operation should been desired. Therefore the health and safety of the public would not have been it have adversely affected.
Operability is defined in the Technical Specifications as:
"A system, subsystem, train, component or device shall be OPERABLE or have OPERABILITY when it is capable of performing its specified function(s), and when all necessary attendant instrumentation, controls, electrical power, cooling or seal water, lubrication or other auxiliary equipment that are required for the system, subsys'tern, train, component, or device to perform its function(s) are also capable of performing their related support function(s)."
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION FACILITY NAME DOCKET NUMBER LER NUMBER PAGE NO.
TURKEY POINT UNIT 3 05000250 98-002-00 6 OF 7 The analysis described above demonstrates that, as a consequence of an accident, one recirculation loop, i.e., MOV-*-863B, could become inoperable in that the valve could not be opened by operator actions specified in current procedures. Accordingly, MOV-
The Train "A" recirculation loop is properly protected and will not fail as a consequence of the condition reported herein. Relay PC-3-601X is powered from breaker 3P22-09. Relay PC-4-601X is powered from breaker 4P24-06. There are no other devices powered by these breakers. Therefore MOV-*-863A remained OPERABLE.
Declaring MOV-863B inoperable on each unit placed each unit in a 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> action statement under Technical Specification 3/4.5.2.a.
IV. CORRECTIVE ACTIONS
- 1) PC-*-600X has been repowered from a dedicated, appropriately protected, safety related power supply (bzeakers 3P21-09 and 4P23-05). There are no other loads on these breakers.
- 2) Drawings are being revised to reflect the change of power supplies to PC-*-600X.
- 3) Turkey Point is evaluating separation and breaker/fuse coordination for other equipment powered from the 120 VAC instrument panels.
- 4) Since 1984, enhanced design information and design basis information, including enhanced configuration contzol documents (vital AC load list, Total Equipment Database) have been made available for engineering use, which would minimize similar personnel design errors.
- 5) Since 1984, design change instructions have been revised to require consideration of electrical separation criteria and other critical design criteria.
- 6) In the late 1980's, Turkey Point completed a design basis reconsititution program, resulting in a set of Design Basis Documents, which further aid in ensuring design criteria are considered.
V. ADDITIONAL INFORMATION Similar events: LER 250/84-18 reported the original design deficiency in the control circuitry for MOV-*-863A and B.
B. EIIS Codes are shown in the format [EIIS SYSTEM: IEEE component function identifier, second component identifier (if appropriate)].
C. A simplified one-line wiring diagram showing the devices powered from breaker 3(4) P6-10 is attached, to aid in understanding the reported condition.
(i' LZCENSgE NT REPORT (LER) TEXT ONTZNUATXON I
FAClLETY NAME DOCKET NUMBER LER NUMBER PAGE NO.
TURKEY POINT UNlT 3 05000250 98-002-00 7 OF 7 3QR47 3P06 FCCO WATER CONTROL 4 RCACTOR TRIP ANNVH RCtAYS RNR RCIAY PC dOOX MOY-5-IISC-X CYCS IHTCRLOCK I OA SETWEEN LCY 115C ANO LCY 1159 SORATIOH CONTROL AVX RELAYS FIC 5 154X FIC 5 154 795200 RCP SCAL WATER SYPASS UIW FLOW LT 5 470 PRESSVRIZER REUL'F TANK LYL TRANS 14 FT CL OISIOE SIO WALL L'f-5 100$
REACTOR COOtANT ORAIH TANK LYL TRANS 14 fT CL INSIOE e)0 WALL FIC 5 d29 RCP SA CCW RETVRH fLOW SY PASS ROTAMCTER 14 fT CL OVTSIOC SIO WALL TT 5-1055 REACTOR COOLANT ORAIH TANK TEMP TRANS 14 FT CL INSIOC CONTAINMENT SIO WAIL
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