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Category:LICENSEE EVENT REPORT (SEE ALSO AO
MONTHYEARML20029D6131994-04-29029 April 1994 LER 94-005-00:on 940330,fire Suppression Water Supply Sys Declared Inoperable.Caused by Inadequate Design of cross- Connection Portion of Svc Water Sys & Inadequate Procedures. Valve SW-8 Tagged Shut to Prevent re-opening.W/940429 Ltr ML20046B4901993-07-30030 July 1993 LER 93-008-00:on 930701,discovered That During Previous Surveillance Testing on 910515,pump Differential Pressure Entered IST Required Action Range Due to Personnel Error. Plant Procedure AP 0164 Will Be revised.W/930730 Ltr ML20046A1141993-07-16016 July 1993 LER 93-007-00:on 930609,determined That Daily Instrument Checks Required by TS Were Not Included in Operator Rounds. Caused by Mgt & Human Factors Weakness.Ts Proposed Change & Amend Issue Process Will Be performed.W/930716 Ltr ML20045G5991993-07-0707 July 1993 LER 93-001-02:on 921217,indeterminate Fire Penetration Seal Configuration Identified When Insulation Removed from Piping.On 930324,addl Indeterminate Seals Identified.Fire Watches Established & New Seals installed.W/930707 Ltr ML20045D9191993-06-24024 June 1993 LER 93-006-00:on 930527,both Core Spray Sys Trains a & B Declared Inoperable When Calibr Procedure Error Resulted in Setpoint Set Nonconservatively.Caused by Failure to Apply Head Correction Factor.Procedure corrected.W/930624 Ltr ML18100B2771992-05-20020 May 1992 LER 92-016-00:on 920422,discovered That TS Quarterly Flow Test Not Performed During safety-related HVAC Sys Surveillance of Chilled Water Pump.Caused by Personnel Error.Procedure Re Ref Valves revised.W/920520 Ltr ML18100B2761992-05-19019 May 1992 LER 92-015-00:on 920424,RCIC Sys Declared Inoperable When Sys Flow Controller Meter Indicated Approx 30 Gpm Flow W/ RCIC Not Operating.Caused by Setpoint Drift.Work Orders Initiated to Correct Meter indication.W/920519 Ltr ML20028H7501991-01-23023 January 1991 LER 91-001-00:on 910104,radiation Protection (RP) Technician Entered Posted High Radiation Area W/O Dose Rate Monitoring Device Due to Personnel Error.Technician Relieved of Further RP duties.W/910123 Ltr ML20043G5691990-06-15015 June 1990 LER 90-007-00:on 900515,determined That Concentration of Old Bottle of Ammonia Span Gas Not within Spec Causing Ammonia Trip Setting to Be Nonconservative.Caused by Incorrect Certification by Vendor.Bottle replaced.W/900615 Ltr ML20042F3611990-05-0202 May 1990 LER 90-006-00:on 900403,Tech Spec Surveillance Requirement Missed Due to Failure to Include Basis on Tracking List. Caused by Personnel Error.Changes to Master Surveillance List & Any Affected Procedures Will Be made.W/900502 Ltr ML20042F2231990-05-0202 May 1990 LER 90-006-01:on 900403,discovered That Flow Transmitters That Supply Advanced off-gas Sys Flow Indication Had Not Been Calibr.Caused by Failure to Include Procedure on Surveillance List.Personnel retrained.W/900503 Ltr ML20042E1691990-04-12012 April 1990 LER 90-003-00:on 900319,inadvertent Primary Containment Isolation Sys Actuation Occurred.Caused by Lack of Coordination Between Monitor Downscale Setpoint & Monitor Reading.Proper Coordination established.W/900412 Ltr ML20012E9301990-03-22022 March 1990 LER 90-002-00:on 900302,identified That Key Sprinkler Isolation Valve Not Adequately Surveilled.Caused by Personnel Error.Valve Verified as Sealed & Surveillances for Fire Protection Valves revised.W/900322 Ltr ML20012B6061990-03-0808 March 1990 LER-90-001-00:on 900209,primary Containment Isolation Sys Group III Isolation & Subsequent Standby Gas Treatment Sys Initiation Occurred.Caused by Personnel Error.Isolation Reset.Personnel Counseled on Proper procedures.W/900308 Ltr ML20012C4291990-03-0707 March 1990 LER 87-015-01:on 871003,reactor Scram Occurred as Result of Turbine Control Valves Rapid Opening & Subsequent Fast Closure.Caused by Flow Imbalance in Turbine Control Oil Sys. Turbine Startup Procedure revised.W/900207 Ltr ML20006B4701990-01-22022 January 1990 LER 89-026-00:on 891223 & 900105,primary Containment Isolation Sys Group III Isolation & Standby Gas Treatment Sys Initiations Occurred.Caused by Failure of Sensor Converter.Isolation Reset & Monitor bypassed.W/900122 Ltr ML20005E1511989-12-26026 December 1989 LER 89-025-00:on 891128,primary Containment Isolation Sys Group III & Standby Gas Treatment Sys Initiation Occurred. Caused by Failure of Reactor Bldg Ventilation Radiation Monitor/Sensor Converter.Converter replaced.W/891226 Ltr ML20011D4901989-12-20020 December 1989 LER 89-024-01:on 890913,while Reviewing RHR Sys Surveillance Procedure,Determined That Leak Testing of RHR Valve V10-18 Not Incorporated & Implemented in Rev 9.Caused by Incomplete Review.Event Reviewed w/personnel.W/891220 Ltr ML19327A8881989-10-13013 October 1989 LER 89-024-00:on 890913,noted That Requirement from Previous Inservice Test Program Rev 9 Re Leak Testing of Valve V10-18 Not Incorporated & Implemented.Caused by Incomplete Review & Omission.Procedure Changes implemented.W/891013 Ltr ML19325C7821989-10-11011 October 1989 LER 89-023-00:on 890911,discovered That Remote Indication to Valve RHR-20 Not Available from 890320-0912,when Supply Breaker Replaced.Caused by Lack of Personnel Recognition. Breaker Replaced & Indication restored.W/891011 Ltr ML20024A8681983-06-22022 June 1983 LER 83-015/01T-0:on 830608,error Discovered in Spacing Table Developed for Support of Copper Piping in Svc Water Sys.Addl Supports Required to Fully Comply W/Ansi B31.1.W/830622 Ltr ML20024A8311983-06-0909 June 1983 LER 83-015/01P-0:on 830608,Yankee Atomic Electric Co Informed Util That Addl Piping Supports Required to Support Piping in Svc Water Sys & Torus Attached Piping.Cause & Corrective Actions to Be Provided in Next rept.W/830609 Ltr ML20024A3441983-06-0707 June 1983 LER 83-014/03L-0:on 830510,discovered Surveillance Frequency for Svc Water Processs Monitor Exceeded Tech Specs.Caused by Schedule Error.Analysis Immediately Performed.Applicable Personnel reinstructed.W/830607 Ltr ML20024A4151983-05-13013 May 1983 LER 83-013/03L-0:on 830413,while Reactor Shutdown,Weekly Environ Air Sample for 830405-12 at Station AT1.3 Not Obtained.Caused by Technician Failure to Test for Sys Vacuum.Technician Reinstructed in procedure.W/830513 Ltr ML20023B4741983-04-25025 April 1983 LER 83-011/03L-0:on 830325,during Visual Insp,Shock Suppressor MS-6 on Main Steam a Piping Found W/No Visible Fluid in Sight Glass & Failed to Lock Up.Caused by Damaged Lenztee.Snubber Cleaned & Rebuilt ML20028F3741983-01-21021 January 1983 LER 83-002/02T-0:on 830108,discovered Leak in 2-inch Stainless Steel Schedule 160 Isolable Section of Reactor Drain Line.Cause Unknown.Leaking Elbow Replaced w/304L Type Stainless Steel Matl Per NUREG-0313 Requirements ML20028F3921983-01-19019 January 1983 LER 82-026/03L-0:on 821220,while Shifting from Reactor Bldg Closed Cooling Water HX B to A,Closed Cooling Water Temp Rapidly Dropped 20 F.Caused by Increased Efficiency of HX Upon Cleaning ML20028D5591983-01-10010 January 1983 LER 83-001/01P-0:on 830107,valves V-16-19-20 & 22B Failed to Close When Operator Attempted to Secure Nitrogen Flow.Caused by Accumulation of Iron Particles on Magnet Used to Provide Valve Position Indication.Valves Cleaned ML20028D5421983-01-10010 January 1983 LER 83-002/01P-0:on 830108,indication of Leak in 2-inch Stainless Steel Schedule 160 Isolable Section of Reactor Drain Line Found.Caused by Pipe Crack.Cause of Pipe Crack Unknown.Elbow Replaced w/304L Type Stainless Steel Matl ML20028A3601982-11-0303 November 1982 LER 82-022/03L-0:on 821005,diesel Generator a Failed to Reach Required Voltage & Frequency within Tech Spec Time Limit.Caused by Fuel Oil Return Line Check Valve Failure. Valve Replaced ML20052C0051982-04-23023 April 1982 LER 82-007/01T-1:on 820309,standby Liquid Control Storage Tank Level & Sodium Pentaborate Concentration Calculations Did Not Correctly Account for Specific Gravity of Sodium Pentaborate.Caused by Procedure Equation Errors ML20052C0451982-04-23023 April 1982 LER 82-003/01T-1:on 820220,boron Concentration Fell Below Tech Spec Requirement.Caused by Apparent Boron Loss Coupled W/Small Sodium Pentaborate Concentration Margin ML20050B3941982-03-25025 March 1982 LER 82-005/03L-0:on 820223,uninterruptible Ac Electric Power Sys Tripped & Lost Power to Motor Control Ctr 89B, Rendering Sys Inoperable.Caused by Shorted Out Transient Suppression Capacitor Due to Aging.Capacitor Replaced ML20050A9291982-03-23023 March 1982 LER 82-007/01T-0:on 820309,calculations of Standby Liquid Control Storage Tank Concentration Versus Tank Level Correlation Did Not Account for Specific Gravity of Sodium Penaborate.Procedures Corrected ML20050A3781982-03-21021 March 1982 LER 82-006/03L-0:on 820219,during Normal Surveillance on Differential Pressure Switches DPIS 2-120 A,B,C & D,Switches A,B & C Found to Be Out of Tech Spec Limits.Caused by Setpoint Drift.Switches Reset to within Required Tolerance ML20042B2361982-03-16016 March 1982 LER 82-004/03L-0:on 820216,discovered That Continuous Environ Air Sample Not Obtainable at Station AT1.4 Per Tech Spec.Caused by Solder Lug of Std 125V-8A Power Toggle Switch Parting at 90 Degree Bend.Faulty Switch Replaced ML20042A4111982-03-0909 March 1982 LER 82-007/01P-0:on 820309,error Revealed in Calculations of Sodium Pentaborate Concentration in SLC Tank.Caused by Specific Gravity of Solution Not Being Factored Into Weight Percent Calculation in Accordance W/Tech Specs ML20042A6031982-03-0606 March 1982 LER 82-003/01T-0:on 820208,sample of Standby Liquid Control Boron Concentration Below Tech Spec Limits.Investigation in Progress.Administrated Limit & Sampling Frequency Increased ML20041F9281982-03-0303 March 1982 LER 82-002/03L-0:on 820206,ac Ground & Blown Fuse Alarms Activated,Rendering Trouble Alarm UPS-B Inoperable.Caused by Blown Fuse M Transient Suppression Circuit Due to Shorted Out Capacitor Off Board 2A 17 ML20041D7771982-02-25025 February 1982 LER 82-001/03L-0:on 820128,IRM Channel B Declared Inoperable.Caused by Failed Voltage Pre AMP (GE 112C-2218G001).Half Scram Manually Initiated.Component Will Be Repaired Prior to Entering IRM Range ML20041D4281982-02-22022 February 1982 LER 82-003/01P-0:on 820220,after Addition of Water to SLC Tank,Solution Sample Found Boron Concentration Below Required Amounts.Cause Unknown.Administrative Limit for Concentration Will Be Increased & Addl Sampling Conducted ML20040E2581982-01-26026 January 1982 LER 81-037/03L-0:on 811227,while Attempting to Start RHRSW Pump P-8-1A,breaker Tripped Contrary to Tech Specs.Caused by Worn Bushings on Operating Mechanism.Circuit Breaker Replaced.Breaker Mfg by Ge,Model Am 4.16 250-8HB ML20040C6971982-01-16016 January 1982 LER 81-036/03L-0:on 811217,containment Isolation Valve CU-15 Failed to Seat Satisfactorily Per Tech Spec 4.7.D.1 During Quarterly Surveillance Testing.Caused by Failure of Closing Torque Switch.Torque Switch Will Be Replaced Next Shutdown ML20040B1941981-12-30030 December 1981 Updated 81-028/03X-1:on 811017,field Breaker Failed to Open, Effectively Disabling Rrmg Set Recirculation Pump Trip Instrumentation.Caused by Binding of Operating Mechanism.New Breaker Installed ML20039F0101981-12-30030 December 1981 LER 81-035/03L-0:on 811204,during Core Spray Valve Test, Breaker for V14-11A Tripped & Reactor Shutdown Commenced. Caused by Breaker Not Latching When Closed,Allowing Breaker to Trip Below Setpoint.Breaker Replaced ML20039C2991981-12-18018 December 1981 LER 81-032/03L-0:on 811120,valves RWCU 68 & 15 Found to Have Seat Leakages Exceeding Tech Spec Range.Cause Not Stated. Disc Replaced & Valves Satisfactorily Retested ML20039C3071981-12-18018 December 1981 LER 81-034/03L-0:on 811121,operating Cycle Test of Standby Gas Treatment HEPA Filters Found Not to Have Been Done Since Sept 1979.Caused by Failure to Include Test on Dept Surveillance List.Test Completed & Schedule Revised ML20039C1121981-12-17017 December 1981 Updated LER 81-011/03X-1:on 810507,leak Discovered in Socket Weld Reducing Fitting.Caused by Intergranular Stress Corrosion Cracking.All Similar Fittings Replaced W/Differently Designed Fitting Less Susceptible to Failure ML20039C3821981-12-17017 December 1981 Updated LER 81-016/03X-1:on 810622,small Leak Found in Socket Weld Reducing Fitting in Vent Line of Regenerative Heat Exchanger E-15-1A.Caused by Intergranular Stress Corrosion Cracking Due to Wetting of Asbestos Insulation ML20039B1281981-12-0909 December 1981 LER 81-033/01T-0:on 811125,reactor Bldg Roof Hatch Opened by Work Crew W/O Notice to Supervisor Until Fire Permit for Welding Requested.Caused by Personnel Error.Personnel Reinstructed Re Procedural Requirement 1994-04-29
[Table view] Category:RO)
MONTHYEARML20029D6131994-04-29029 April 1994 LER 94-005-00:on 940330,fire Suppression Water Supply Sys Declared Inoperable.Caused by Inadequate Design of cross- Connection Portion of Svc Water Sys & Inadequate Procedures. Valve SW-8 Tagged Shut to Prevent re-opening.W/940429 Ltr ML20046B4901993-07-30030 July 1993 LER 93-008-00:on 930701,discovered That During Previous Surveillance Testing on 910515,pump Differential Pressure Entered IST Required Action Range Due to Personnel Error. Plant Procedure AP 0164 Will Be revised.W/930730 Ltr ML20046A1141993-07-16016 July 1993 LER 93-007-00:on 930609,determined That Daily Instrument Checks Required by TS Were Not Included in Operator Rounds. Caused by Mgt & Human Factors Weakness.Ts Proposed Change & Amend Issue Process Will Be performed.W/930716 Ltr ML20045G5991993-07-0707 July 1993 LER 93-001-02:on 921217,indeterminate Fire Penetration Seal Configuration Identified When Insulation Removed from Piping.On 930324,addl Indeterminate Seals Identified.Fire Watches Established & New Seals installed.W/930707 Ltr ML20045D9191993-06-24024 June 1993 LER 93-006-00:on 930527,both Core Spray Sys Trains a & B Declared Inoperable When Calibr Procedure Error Resulted in Setpoint Set Nonconservatively.Caused by Failure to Apply Head Correction Factor.Procedure corrected.W/930624 Ltr ML18100B2771992-05-20020 May 1992 LER 92-016-00:on 920422,discovered That TS Quarterly Flow Test Not Performed During safety-related HVAC Sys Surveillance of Chilled Water Pump.Caused by Personnel Error.Procedure Re Ref Valves revised.W/920520 Ltr ML18100B2761992-05-19019 May 1992 LER 92-015-00:on 920424,RCIC Sys Declared Inoperable When Sys Flow Controller Meter Indicated Approx 30 Gpm Flow W/ RCIC Not Operating.Caused by Setpoint Drift.Work Orders Initiated to Correct Meter indication.W/920519 Ltr ML20028H7501991-01-23023 January 1991 LER 91-001-00:on 910104,radiation Protection (RP) Technician Entered Posted High Radiation Area W/O Dose Rate Monitoring Device Due to Personnel Error.Technician Relieved of Further RP duties.W/910123 Ltr ML20043G5691990-06-15015 June 1990 LER 90-007-00:on 900515,determined That Concentration of Old Bottle of Ammonia Span Gas Not within Spec Causing Ammonia Trip Setting to Be Nonconservative.Caused by Incorrect Certification by Vendor.Bottle replaced.W/900615 Ltr ML20042F3611990-05-0202 May 1990 LER 90-006-00:on 900403,Tech Spec Surveillance Requirement Missed Due to Failure to Include Basis on Tracking List. Caused by Personnel Error.Changes to Master Surveillance List & Any Affected Procedures Will Be made.W/900502 Ltr ML20042F2231990-05-0202 May 1990 LER 90-006-01:on 900403,discovered That Flow Transmitters That Supply Advanced off-gas Sys Flow Indication Had Not Been Calibr.Caused by Failure to Include Procedure on Surveillance List.Personnel retrained.W/900503 Ltr ML20042E1691990-04-12012 April 1990 LER 90-003-00:on 900319,inadvertent Primary Containment Isolation Sys Actuation Occurred.Caused by Lack of Coordination Between Monitor Downscale Setpoint & Monitor Reading.Proper Coordination established.W/900412 Ltr ML20012E9301990-03-22022 March 1990 LER 90-002-00:on 900302,identified That Key Sprinkler Isolation Valve Not Adequately Surveilled.Caused by Personnel Error.Valve Verified as Sealed & Surveillances for Fire Protection Valves revised.W/900322 Ltr ML20012B6061990-03-0808 March 1990 LER-90-001-00:on 900209,primary Containment Isolation Sys Group III Isolation & Subsequent Standby Gas Treatment Sys Initiation Occurred.Caused by Personnel Error.Isolation Reset.Personnel Counseled on Proper procedures.W/900308 Ltr ML20012C4291990-03-0707 March 1990 LER 87-015-01:on 871003,reactor Scram Occurred as Result of Turbine Control Valves Rapid Opening & Subsequent Fast Closure.Caused by Flow Imbalance in Turbine Control Oil Sys. Turbine Startup Procedure revised.W/900207 Ltr ML20006B4701990-01-22022 January 1990 LER 89-026-00:on 891223 & 900105,primary Containment Isolation Sys Group III Isolation & Standby Gas Treatment Sys Initiations Occurred.Caused by Failure of Sensor Converter.Isolation Reset & Monitor bypassed.W/900122 Ltr ML20005E1511989-12-26026 December 1989 LER 89-025-00:on 891128,primary Containment Isolation Sys Group III & Standby Gas Treatment Sys Initiation Occurred. Caused by Failure of Reactor Bldg Ventilation Radiation Monitor/Sensor Converter.Converter replaced.W/891226 Ltr ML20011D4901989-12-20020 December 1989 LER 89-024-01:on 890913,while Reviewing RHR Sys Surveillance Procedure,Determined That Leak Testing of RHR Valve V10-18 Not Incorporated & Implemented in Rev 9.Caused by Incomplete Review.Event Reviewed w/personnel.W/891220 Ltr ML19327A8881989-10-13013 October 1989 LER 89-024-00:on 890913,noted That Requirement from Previous Inservice Test Program Rev 9 Re Leak Testing of Valve V10-18 Not Incorporated & Implemented.Caused by Incomplete Review & Omission.Procedure Changes implemented.W/891013 Ltr ML19325C7821989-10-11011 October 1989 LER 89-023-00:on 890911,discovered That Remote Indication to Valve RHR-20 Not Available from 890320-0912,when Supply Breaker Replaced.Caused by Lack of Personnel Recognition. Breaker Replaced & Indication restored.W/891011 Ltr ML20024A8681983-06-22022 June 1983 LER 83-015/01T-0:on 830608,error Discovered in Spacing Table Developed for Support of Copper Piping in Svc Water Sys.Addl Supports Required to Fully Comply W/Ansi B31.1.W/830622 Ltr ML20024A8311983-06-0909 June 1983 LER 83-015/01P-0:on 830608,Yankee Atomic Electric Co Informed Util That Addl Piping Supports Required to Support Piping in Svc Water Sys & Torus Attached Piping.Cause & Corrective Actions to Be Provided in Next rept.W/830609 Ltr ML20024A3441983-06-0707 June 1983 LER 83-014/03L-0:on 830510,discovered Surveillance Frequency for Svc Water Processs Monitor Exceeded Tech Specs.Caused by Schedule Error.Analysis Immediately Performed.Applicable Personnel reinstructed.W/830607 Ltr ML20024A4151983-05-13013 May 1983 LER 83-013/03L-0:on 830413,while Reactor Shutdown,Weekly Environ Air Sample for 830405-12 at Station AT1.3 Not Obtained.Caused by Technician Failure to Test for Sys Vacuum.Technician Reinstructed in procedure.W/830513 Ltr ML20023B4741983-04-25025 April 1983 LER 83-011/03L-0:on 830325,during Visual Insp,Shock Suppressor MS-6 on Main Steam a Piping Found W/No Visible Fluid in Sight Glass & Failed to Lock Up.Caused by Damaged Lenztee.Snubber Cleaned & Rebuilt ML20028F3741983-01-21021 January 1983 LER 83-002/02T-0:on 830108,discovered Leak in 2-inch Stainless Steel Schedule 160 Isolable Section of Reactor Drain Line.Cause Unknown.Leaking Elbow Replaced w/304L Type Stainless Steel Matl Per NUREG-0313 Requirements ML20028F3921983-01-19019 January 1983 LER 82-026/03L-0:on 821220,while Shifting from Reactor Bldg Closed Cooling Water HX B to A,Closed Cooling Water Temp Rapidly Dropped 20 F.Caused by Increased Efficiency of HX Upon Cleaning ML20028D5591983-01-10010 January 1983 LER 83-001/01P-0:on 830107,valves V-16-19-20 & 22B Failed to Close When Operator Attempted to Secure Nitrogen Flow.Caused by Accumulation of Iron Particles on Magnet Used to Provide Valve Position Indication.Valves Cleaned ML20028D5421983-01-10010 January 1983 LER 83-002/01P-0:on 830108,indication of Leak in 2-inch Stainless Steel Schedule 160 Isolable Section of Reactor Drain Line Found.Caused by Pipe Crack.Cause of Pipe Crack Unknown.Elbow Replaced w/304L Type Stainless Steel Matl ML20028A3601982-11-0303 November 1982 LER 82-022/03L-0:on 821005,diesel Generator a Failed to Reach Required Voltage & Frequency within Tech Spec Time Limit.Caused by Fuel Oil Return Line Check Valve Failure. Valve Replaced ML20052C0051982-04-23023 April 1982 LER 82-007/01T-1:on 820309,standby Liquid Control Storage Tank Level & Sodium Pentaborate Concentration Calculations Did Not Correctly Account for Specific Gravity of Sodium Pentaborate.Caused by Procedure Equation Errors ML20052C0451982-04-23023 April 1982 LER 82-003/01T-1:on 820220,boron Concentration Fell Below Tech Spec Requirement.Caused by Apparent Boron Loss Coupled W/Small Sodium Pentaborate Concentration Margin ML20050B3941982-03-25025 March 1982 LER 82-005/03L-0:on 820223,uninterruptible Ac Electric Power Sys Tripped & Lost Power to Motor Control Ctr 89B, Rendering Sys Inoperable.Caused by Shorted Out Transient Suppression Capacitor Due to Aging.Capacitor Replaced ML20050A9291982-03-23023 March 1982 LER 82-007/01T-0:on 820309,calculations of Standby Liquid Control Storage Tank Concentration Versus Tank Level Correlation Did Not Account for Specific Gravity of Sodium Penaborate.Procedures Corrected ML20050A3781982-03-21021 March 1982 LER 82-006/03L-0:on 820219,during Normal Surveillance on Differential Pressure Switches DPIS 2-120 A,B,C & D,Switches A,B & C Found to Be Out of Tech Spec Limits.Caused by Setpoint Drift.Switches Reset to within Required Tolerance ML20042B2361982-03-16016 March 1982 LER 82-004/03L-0:on 820216,discovered That Continuous Environ Air Sample Not Obtainable at Station AT1.4 Per Tech Spec.Caused by Solder Lug of Std 125V-8A Power Toggle Switch Parting at 90 Degree Bend.Faulty Switch Replaced ML20042A4111982-03-0909 March 1982 LER 82-007/01P-0:on 820309,error Revealed in Calculations of Sodium Pentaborate Concentration in SLC Tank.Caused by Specific Gravity of Solution Not Being Factored Into Weight Percent Calculation in Accordance W/Tech Specs ML20042A6031982-03-0606 March 1982 LER 82-003/01T-0:on 820208,sample of Standby Liquid Control Boron Concentration Below Tech Spec Limits.Investigation in Progress.Administrated Limit & Sampling Frequency Increased ML20041F9281982-03-0303 March 1982 LER 82-002/03L-0:on 820206,ac Ground & Blown Fuse Alarms Activated,Rendering Trouble Alarm UPS-B Inoperable.Caused by Blown Fuse M Transient Suppression Circuit Due to Shorted Out Capacitor Off Board 2A 17 ML20041D7771982-02-25025 February 1982 LER 82-001/03L-0:on 820128,IRM Channel B Declared Inoperable.Caused by Failed Voltage Pre AMP (GE 112C-2218G001).Half Scram Manually Initiated.Component Will Be Repaired Prior to Entering IRM Range ML20041D4281982-02-22022 February 1982 LER 82-003/01P-0:on 820220,after Addition of Water to SLC Tank,Solution Sample Found Boron Concentration Below Required Amounts.Cause Unknown.Administrative Limit for Concentration Will Be Increased & Addl Sampling Conducted ML20040E2581982-01-26026 January 1982 LER 81-037/03L-0:on 811227,while Attempting to Start RHRSW Pump P-8-1A,breaker Tripped Contrary to Tech Specs.Caused by Worn Bushings on Operating Mechanism.Circuit Breaker Replaced.Breaker Mfg by Ge,Model Am 4.16 250-8HB ML20040C6971982-01-16016 January 1982 LER 81-036/03L-0:on 811217,containment Isolation Valve CU-15 Failed to Seat Satisfactorily Per Tech Spec 4.7.D.1 During Quarterly Surveillance Testing.Caused by Failure of Closing Torque Switch.Torque Switch Will Be Replaced Next Shutdown ML20040B1941981-12-30030 December 1981 Updated 81-028/03X-1:on 811017,field Breaker Failed to Open, Effectively Disabling Rrmg Set Recirculation Pump Trip Instrumentation.Caused by Binding of Operating Mechanism.New Breaker Installed ML20039F0101981-12-30030 December 1981 LER 81-035/03L-0:on 811204,during Core Spray Valve Test, Breaker for V14-11A Tripped & Reactor Shutdown Commenced. Caused by Breaker Not Latching When Closed,Allowing Breaker to Trip Below Setpoint.Breaker Replaced ML20039C2991981-12-18018 December 1981 LER 81-032/03L-0:on 811120,valves RWCU 68 & 15 Found to Have Seat Leakages Exceeding Tech Spec Range.Cause Not Stated. Disc Replaced & Valves Satisfactorily Retested ML20039C3071981-12-18018 December 1981 LER 81-034/03L-0:on 811121,operating Cycle Test of Standby Gas Treatment HEPA Filters Found Not to Have Been Done Since Sept 1979.Caused by Failure to Include Test on Dept Surveillance List.Test Completed & Schedule Revised ML20039C1121981-12-17017 December 1981 Updated LER 81-011/03X-1:on 810507,leak Discovered in Socket Weld Reducing Fitting.Caused by Intergranular Stress Corrosion Cracking.All Similar Fittings Replaced W/Differently Designed Fitting Less Susceptible to Failure ML20039C3821981-12-17017 December 1981 Updated LER 81-016/03X-1:on 810622,small Leak Found in Socket Weld Reducing Fitting in Vent Line of Regenerative Heat Exchanger E-15-1A.Caused by Intergranular Stress Corrosion Cracking Due to Wetting of Asbestos Insulation ML20039B1281981-12-0909 December 1981 LER 81-033/01T-0:on 811125,reactor Bldg Roof Hatch Opened by Work Crew W/O Notice to Supervisor Until Fire Permit for Welding Requested.Caused by Personnel Error.Personnel Reinstructed Re Procedural Requirement 1994-04-29
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217L8831999-10-21021 October 1999 Safety Evaluation Supporting Proposed Alternatives to Code Requirements Described in RR-V17 & RR-V18 ML20217G2041999-10-13013 October 1999 Safety Evaluation Supporting Amend 179 to License DPR-28 BVY-99-127, Monthly Operating Rept for Sept 1999 for Vermont Yankee Nuclear Power Station.With1999-09-30030 September 1999 Monthly Operating Rept for Sept 1999 for Vermont Yankee Nuclear Power Station.With ML20212C2551999-09-17017 September 1999 Safety Evaluation Supporting Amend 175 to License DPR-28 BVY-99-112, Monthly Operating Rept for Aug 1999 for Vermont Yankee.With1999-08-31031 August 1999 Monthly Operating Rept for Aug 1999 for Vermont Yankee.With BVY-99-109, Ro:On 990812,stack Ng Effluent Instrumentation for PAM Was Declared Oos.Caused by Instrument Drift Due to Electronic Components Based on Insps by Instrumentation & Controls Dept.Detector & Preamplifier Will Be Replaced on 9908311999-08-19019 August 1999 Ro:On 990812,stack Ng Effluent Instrumentation for PAM Was Declared Oos.Caused by Instrument Drift Due to Electronic Components Based on Insps by Instrumentation & Controls Dept.Detector & Preamplifier Will Be Replaced on 990831 BVY-99-102, Monthly Operating Rept for July 1999 for Vermont Yankee. with1999-07-31031 July 1999 Monthly Operating Rept for July 1999 for Vermont Yankee. with ML20209J0081999-07-14014 July 1999 Special Rept:On 990615,diesel Driven Fire Pump Failed to Achieve Rated Flow of 2500 Gallons Per Minute.Pump Was Inoperable for Greater than 7 Days.Corrective Maint Was Performed to Reset Pump Lift Setting BVY-99-090, Monthly Operating Rept for June 1999 for Vermont Yankee Nuclear Power Station.With1999-06-30030 June 1999 Monthly Operating Rept for June 1999 for Vermont Yankee Nuclear Power Station.With ML20196G5071999-06-23023 June 1999 Vynp Assessment of On-Site Disposal of Contaminated Soil by Land Spreading BVY-99-077, Monthly Operating Rept for May 1999 for Vermont Yankee Nuclear Power Station.With1999-05-31031 May 1999 Monthly Operating Rept for May 1999 for Vermont Yankee Nuclear Power Station.With BVY-99-068, Monthly Operating Rept for Apr 1999 for Vynp.With1999-04-30030 April 1999 Monthly Operating Rept for Apr 1999 for Vynp.With ML20206E8741999-04-29029 April 1999 SER Determined That Flaw Evaluation Meets Rules of ASME Code & Assumed Crack Growth Rate Adequate for Application ML20206D9301999-04-27027 April 1999 1999 Emergency Preparedness Exercise 990427 Exercise Manual (Plume Portion) ML20205S4211999-04-16016 April 1999 Non-proprietary Version of Revised Page 4-3 of HI-981932 Technical Rept for Vermont Yankee Spent Fuel Pool Storage Expansion ML20205K7581999-04-0707 April 1999 Safety Evaluation Supporting Alternative Proposal for Reexamination of Circumferential Welds with Detected Flaw Indications in Plant RPV BVY-99-046, Monthly Operating Rept for Mar 1999 for Vermont Yankee Nuclear Power Station.With1999-03-31031 March 1999 Monthly Operating Rept for Mar 1999 for Vermont Yankee Nuclear Power Station.With ML20205F6631999-03-0404 March 1999 Jet Pump Riser Weld Leakage Evaluation BVY-99-035, Monthly Operating Rept for Feb 1999 for Vermont Yankee Nuclear Station.With1999-02-28028 February 1999 Monthly Operating Rept for Feb 1999 for Vermont Yankee Nuclear Station.With ML20205P8241999-02-28028 February 1999 Rev 2 to Vermont Yankee Cycle 20 Colr ML20203H9881999-02-18018 February 1999 SER Accepting Alternative to 10CFR50.55a(g)(6)(ii)(A) Augmented Reactor Vessel Exam at Vermont Yankee Nuclear Power Station.Technical Ltr Rept Encl ML20203A6951999-02-0404 February 1999 Revised Rev 2,App B to Vermont Yankee Operational QA Manual (Voqam) ML20199K7151999-01-21021 January 1999 Corrected Safety Evaluation Supporting Amend 163 Issued to FOL DPR-28.Pages 2 & 3 Required Correction & Clarification ML20199K6991999-01-20020 January 1999 Safety Evaluation Concluding That Request to Use YAEC-1339, Yankee Atomic Electric Co Application of FIBWR2 Core Hydraulics Code to BWR Reload Analysis, at Vermont Yankee Acceptable ML20199L5951999-01-14014 January 1999 Safety Evaluation Accepting Licensee Proposed Alternative to Code Requirement,Described in Rev 2 to Pump Relief Request RR-P10 Pursuant to 10CFR50.55a(a)(3)(i) BVY-99-071, Corp 1998 Annual Rept. with1998-12-31031 December 1998 Corp 1998 Annual Rept. with BVY-99-001, Monthly Operating Rept for Dec 1998 for Vermont Yankee Nuclear Power Station1998-12-31031 December 1998 Monthly Operating Rept for Dec 1998 for Vermont Yankee Nuclear Power Station ML20198H5481998-12-23023 December 1998 Rev 2 to Vermont Operational QA Manual,Voqam ML20196H8641998-12-0101 December 1998 Cycle 19 Operating Rept BVY-98-163, Monthly Operating Rept for Nov 1998 for Vermont Yankee Nuclear Power Station.With1998-11-30030 November 1998 Monthly Operating Rept for Nov 1998 for Vermont Yankee Nuclear Power Station.With ML20195C4161998-11-0909 November 1998 SER Accepting Request That NRC Approve ASME Code Case N-560, Alternative Exam Requirement for Class 1,Category B-J Piping Welds BVY-98-154, Monthly Operating Rept for Oct 1998 for Vermont Yankee Nuclear Power Station.With1998-10-31031 October 1998 Monthly Operating Rept for Oct 1998 for Vermont Yankee Nuclear Power Station.With ML20155B6471998-10-26026 October 1998 Safety Evaluation Accepting Jet Pump Riser Insp Results & Flaw Evaluation,Conducted During 1998 Refueling Outage ML20154N0891998-10-16016 October 1998 Rev 1 to Vermont Operational QA Program Manual (Voqam) ML20154B6951998-10-0101 October 1998 SER Re Licensee Response to GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power-Operated Gate Valves, for Vermont Yankee Nuclear Power Station BVY-98-149, Monthly Operating Rept for Sept 1998 for Vermont Yankee Nuclear Power Station.With1998-09-30030 September 1998 Monthly Operating Rept for Sept 1998 for Vermont Yankee Nuclear Power Station.With ML20239A1361998-09-0202 September 1998 SER Re License Request for NRC Review & Concurrence W/Changes to NRC-approved Fire Protection Program BVY-98-135, Monthly Operating Rept for Aug 1998 for Vermont Yankee Nuclear Power Station.With1998-08-31031 August 1998 Monthly Operating Rept for Aug 1998 for Vermont Yankee Nuclear Power Station.With ML20151U0361998-08-28028 August 1998 Non-proprietary Rev 1 to Holtec Rept HI-981932, Vermont Yankee Nuclear Power Station Spent Storage Expansion Project ML20237E9221998-08-20020 August 1998 Vynp 1998 Form NIS-1 Owners Summary Rept for ISI, 961103-980603 BVY-98-122, Monthly Operating Rept for July 1998 for Vermont Yankee Nuclear Power Station1998-07-31031 July 1998 Monthly Operating Rept for July 1998 for Vermont Yankee Nuclear Power Station ML20205F6491998-07-31031 July 1998 Rev 1 to GE-NE-B13-01935-02, Jet Pump Assembly Welds Flaw Evaluation Handbook for Vermont Yankee ML20236G0011998-06-30030 June 1998 Individual Plant Exam External Events BVY-98-098, Monthly Operating Rept for June 1998 for Vermont Yankee Nuclear Power Station1998-06-30030 June 1998 Monthly Operating Rept for June 1998 for Vermont Yankee Nuclear Power Station ML20248C5081998-05-31031 May 1998 Rev 2 to 24A5416, Supplemental Reload Licensing Rept for Vermont Yankee Nuclear Power Station Reload 19 Cycle 20 ML20248C4951998-05-31031 May 1998 Rev 1 to Vermont Yankee Nuclear Power Station Cycle 20 Colr BVY-98-081, Monthly Operating Rept for May 1998 for Vermont Yankee Nuclear Power Station1998-05-31031 May 1998 Monthly Operating Rept for May 1998 for Vermont Yankee Nuclear Power Station ML20247J8341998-05-31031 May 1998 Peak Suppression Pool Temp Analyses for Large Break LOCA Scenarios, for May 1998 ML20247G4001998-05-12012 May 1998 Interview Rept of Ej Massey ML20247E6351998-04-30030 April 1998 Rev 1 to GE-NE-B13-01935-LTR, Jet Pump Riser Welds Allowable Flaw Sizes Ltr Rept for Vermont Yankee 1999-09-30
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{{#Wiki_filter:--
7-VdRMONT YANKEE NUCLEAR POWER CORPORATION Q.
.fk7 P.O. Box 157, Governor Hunt Road l ) Vernon, Vermont 05354-0157
\ fj (802) 257-7711 May 5, 1993 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555
REFERENCE:
Operating License DPR-28 Docket No. 50-271 Reportable Occurrence No. LER 93-05 Dear Sirst As defined by 10 CFR 50.73, we are reporting the attached Reportable Occurrence as LER 93-05 very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION edae Robert J anczyk Plant Manager ec: Regional Administrator USNRC Region I 475 Allendale Road King of Prussia, PA 19406 100071 ,
9305110308 930505 PDR ADOCK 0300 2 1 f.j f/)l l S
_ _ _ - - .- - . - . - - .- _ ~ _ , _- _ ~
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. NRC fers 366 U.S. NUCLEAR REGULATORY CO* !$$10N APPROVED OMS No. 3150-0104 f (6-89) EXPIKES 4/30/92 [
ESTIMATED BURDE3 PER RESPONSE TO COMPLY WITH THIS j INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD ComENTS REGARDlWG BURDEN ESTIMATE TO THE RECORDS AND !
REFORTS MANAGEMENT BRANCH (P.350), U.S. NUCLEAR REGULATORY i COMMISSION, WASHINGTON DC 20555, AND TO THE PAPERWORK !
REDUCTION PROJECT (3160-0104), OFFICE OF MANAGEMENT AND [
BLDGET, WASHINGTON, DC 20603. i FACILITY WAME (1) DOCKET NO. (2) I PAGE (3)
VERMONT YANKEE NUCLEAR POWER STATION 0l5l0l0l0l2l7l1 0 1 0F 0 4 f
TITLE (4) CONTROL ROD DRIVE SCRAM TIMES GREATER THAh THAT REQUIRED BY TECHNICAL $PECIFICATIONS DUE TO SCRAM SOLENDID PILOT VALVE COMPONENTS f
)
i EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8) !
' I MONTH DAY YEAR YEAR SEC # REV # MONTH DAY YEAR FACILITY NAMES DOCKET Wo. ($)
- 0 5 0 0 0 0 4 0 6 9 3 9 3 -
0 0 5 -
0 0 0 5 0 5 9 3 0 5 0 0 0
{
OPERATING THIS REPORT t$ SUBMITTED PURSUANT TO RE0'M1S OF 10 CFR i: CHECK ONE OR MORE (11) (
MODE (9) i N 20.402(b) 20.405(c) 50.73(a)(2)(Iv) 73.71(b) f i
d l PcWER 20.405(a)(1)(1) 50.36(c)(1) 50.73(a)(2)(v) 73.71(c) i LEVEL (10) l6l0 20.405(a)(1)(ti) 50.36(c)(2) 50.73(a)(2)(vil) OTHER:
l
}
.................. 20.405(a)(1)(iii) X 50.73(a)(2)(i) 50.73(a)(2)(viii)(A)
{
.................. 20.405(a)(1)(iv) X 50.73(a)(2)(ll) 50.73(a)(2)(vill)(s) i
.................. 20.405(a)(1)(v) 50.73(a)(2)(lli) 50.73(a)(2)(x) 5 LICENSEE CONTACT FOR THIS LER (12) i NAME TELEPHONE NO.
l AREA
- CODE ROBERT J. WANCZYK, PLANT MANAGER 8l0l2 2l5l7l-l7l7l1l1 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13) !
CAUSE SYST COMPONENT MFR REPORTABLE CAUSE SYST COMPONENT MFR REPORTABLE TO NPRDS .... TO NPRDS .... l B
AlA lFl5lV Al4l9l9 Y .... NA l l l l l l l l
"a F l l II IIi "a i i ll II :
SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED M0 DAY YR -l SUBMISSION ;
DATE (15) ;
X YES (If yes, conplete EXPECTED SUBMIS$10N DATE) No 0l7 1l5 9l3 l ABSTRACT (Limit to 1400 spaces, i.e., approx. fifteen single-space typewritten lines) (16) I On 4/6/93, following Control Rod Drive scram time testing, it was concluded that the core average scram time and the <
b scram times of seven (7) of the 2X2 control rod arrays at notch forty-six (46) were n0t in compliance with Technical Specifications (TS) Section 3.3.C. On 4/6/93, the plant was shutdown due to an unrelated minor leak in the Feedwater : ;
(
System. Subsequent follow-up investigation into past scram time testing revealed that on 10/15/92, initial scram times for one l of the 2X2 arrays, at notch forty-six (46), would not have been in compliance with TS if the *as found" scram time data were j used instead of the *as left* scram time data. '
The apparent cause of the slow scram times is attributable to component parts of the Scram Solenoid Pilot Valves. l The apparent cause for the failure to comply with TS on 10/15/92 is the use of *as left* data instead of *as found" data. The root cause analyses for these events are in progress and will be addressed in a supplemental LER.
Following the 4/6/93 shutdown, immediate corrective actions were to rebuild the Scram Solenoid Pilot Valves to address the slow scram times, and to no longer allow the use of repeated scrams to determine TS compliance. Other corrective actions included forming a task team to investigate the slow scram times, and a task team to investigate possible programmatic issues associated with the everit.
CRC Torin 366 (6-89) -1
.I
\
r
. CRC Fcre 366A U.S. NUCLEAR REGULATORY CapetIS$10N APPROVED OMS No. 3150-0104 ,
(6-89) EMPIRES 4/30/92 ESTIM TED BURDEN PER RESPONSE TO COMPLY UITH THis INFORM TION COLLECTION REQUEST: 50.0 HRS. FORWARD
, LICENSEE EVENT REPORT (LER) COMMENTS REGARDING BURDEN ESTIETE TO THE RECORDS AND [
TEXT CONTINUATION REPORTS MNAGEMENT SRANCH (P-350), U.S. NUCLEAR REGULAt0RY !
COMNISSION, WASHINGTON DC 20555, AND TO THE PAPERWORK {
REDUCTION PROJECT (3160-0104), OFFICE oF MWAGEMENT AND j BLOGET, WASHINGTON, DC 20603. .
i FACILITY NAME (1) DOCKET No (2) LER NUMBER (6) PAGE (3)
YEAR SEQ # REV # f i
9 3 0 0 of VERMONT YANKEE NUCLEAR POWER CoRPORAT]DN 0 5 0 0l2 0l4 0l5l0l0l0l2l7l1 l TEXT (if more space is required, use additional NRC Form 366A) (17) I i
DESCRIPTION l
i On 4/6/93, following Control Rod Drive (El:S = AA) scram time testing, it was concluded that the core average !
scram time and the scram times of seven (7) of the 2X2 control rod arrays, at notch forty-six (46) (*as found"), were not in ;
compliance with TS Section 3.3.C scram time limits. During the course of the 4/6/93 testing, certain control rods were 2 immediately retested and all scram times met the TS requirements. The NRC subsequently granted an Enforcement Discretion l for 48 hours, beginning at 2200 hours on 4/6/93, to preclude a plant shutdown as required by TS. The 48 hour Enforcement ;
, Discretion was based on the fact that a new analysis had concluded that a scram time of 0.5 seconds, at notch forty-six (46), [
still enveloped the worst case transient which is a turbine trip without bypass valves. On 4/6/93 at 2233 hours, a plant !
shutdown was initiated due to a minor leak in the Feedwater System. Subseouent follow-up investigation into past scram time l testing revealed that on 10/15/92 initial scram time (*as found" data) for one of the 2X2 arrays, at notch forty-six (46), was ;
not in compliance with TS. The plant did not shutdown as required by TS Section 3.3.F. The control rods in the 2X2 array had .;
been immediately retested and subsequent scram times ("as left* data ) were within the applicable TS Limits. In the past, !
Vermont Yankee's practice has been to allow scram time retest data (*as left* data) to determine compliance with TS. The l practice of using reteEt data to determine TS compliance has been discontinued. j Following the determination of the slow scram times, a multi-discipline Task Force was formed of plant individuals from Reactor Engineering, instrument & Control, Mechanical Maintenance, Operations, a lead systems engineer for Control Rod Drive ,
Systems from the General Electric Co., as well as a representative from the Automatic Switch Co. to investigate the slow ,
scram times and determine the root cause and subsequent necessary repairs. This included a sub-task force to acquire physical ;
data from the Scram Solenoid Pilot Valve components. A second Task Force was also formed of Yankee Nuclear Service ?
Division personnel to investigate any programmatic issues associated with the event.
?
CAUSE OF EVENT
{
i The apparent cause of the slow scram times is attributable to the Scram Solenoid Pilot Valves. Further investigation j into the component parts of the solenoid is ongoing to determine +.he root cause for the slow scram times. The sub-task force ;
4 team assigned to acquire the physical data could not determine the root cause based on the scram solenoid pilot valve !
components with test equipment at their disposal. Subsequently, the used component parts were sent to General Electric for j further testing. The root cause will be addressed in a supplemental LER.
'l The investigation into the root cause for using *as left* data instead of *as found" data and compliance with TS is j ongoing and will also be addressed in a supplemental LER. i 1
ANALYSIS OF EVENT
-{
The design basis of the Reactivity Control System is to provide sufficient nuclear reactivity control devices (control . l rods) to control the excess reactivity in the core and to provide for adjustment of the control rods to permit power generation. !
The safety function of the Reactivity Contro! System, that applies to this event, is to provide sufficient rapid insertion of control ;
rods so that no fuel damage results from any abnormal operating transient. !
The limiting design transient for this event is a turbine trip without bypass valves.' This event was analyzed by the ,
Yankee Nuclear Services Transient Analysis Group using times that exceeded the TS limits. Although the scram times on - 1 4/6/93 were not initially in compliance with TS, (core averaoe notch 46 time was 0.369 seconds (TS limit of 0.358 seconds) !
and seven of the sixty-eight 2X2 arrays were in the range of 0.380 to 0.418 seconds (TS limit of 0.379 seconds)), the !
conclusion of the analysis is that no present cycle operating limits would be affected if the notch 46 scram time was 0.5 i seconds or less. Additionally, the scram time on 10/15/92 for the one 2X2 array that was not in compliance with TS was ?
0.391 seconds, however, this scram time is also enveloped by the conclusion of the analysis. E i
i NRC Form 366 (6-89)
1
. NRC.Ftra 366A U.S. NUCLEAR REGULATORY C0mlSSloN APPROVED OMS No. 3150-0104 l (6-89) EXPIRES 4/30/92 j ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS !
INFORMATION COLLECT 10W REouEST: 50.0 HRS. FORWARD l 11CENSEE EVENT REPORT (LER) ComENTS REGARD!bG BURDEN ESTIMATE TO THE RECORDS AND l TEXT CONTINUATION REPORTS MANAGEMENT BRANCH (P-350), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON DC 20555, AND TO THE PAPERWORK l REDUCTION PROJECT (3160-0104), OFFICE OF MANAGEMENT AND !
BUoGET, WASHINGTON, DC 20603. ;
FACILITY KAME (1) DOCKET No (2) LER NtMBER (6) PAGE (3) l YFAR SEQ # REV #
)
VERMONT YANKEE WuCLEAR POWER CORPORATION 9 3 0 0 0 0 0l3 0l4 0l5l0l0j0l2l7l1 5 -
OF TEXT (if more space is required, use additional NRC Form 366A) (17)
The 4/6/93 testing was conducted when the plant was at approximately 60% power. During the evaluation of the scram times the plant was held less than 75% power. The above analysis took into account the operating limits at 100%
power.
As the scram times were enveloped by the analyzed times of 0.5 seconds, no safety consequences would have resulted from the as-found scram insertion times for any operational transients. l Prior to startup, all Scram Solenoid Pilot Valves were rebuilt and the control rods were subsequently retested with scram times within the TS scram time limits.
At no time was there any threat to the health and safety of the public.
CORRECTIVE ACTIONS Immediate Corrective Actions
- 1. Following the 4/6/93 testing, the data was evaluated to assess the safety significance of the event and discussions were initiated with the NRC concerning Enforcement Discretion.
Intermediate Corrective Actions
- 1. Following the plant shutdown for the minor leak in the feedwater system, the immediate actions were as follows:
- a. Two tasks teams were formed, one to evaluate the slow scram times, and one to investigate possible programmatic issues associated with failure to comply with TS. A sub-task team was also formed to specifically investigate the physical condition of the Scram Solenoid Pilot Valve components to determine the root cause and review previous test data.
- b. All 178 Scram Solenoid Pilot Valves were rebuilt with new component parts prior to plant startup.
- 2. Cold hydrostatic tests of all 89 control rods were performed to ensure full compliance with TS.
- 3. Following plant startup, single rod scram testing was performed on 100% of the rods. Using *as found" data, the results were within TS lamits.
4 The removed component parts of several of the Scram Solenoid Pilot Velves were sent to General Electric for further analysis to identify the root cause for the slow scram times.
5, A memo was issued from the Plant Manager requiring all departments involved in TS surveillances to evaluate their current assessment practice to ensure margins to limits are monitored and maintained.
- 6. An interim change to the Control Rod Scram Testing and Data Reduction procedure was made prior to startup to ensure compliance with TS.
NRC Forn 366 (6 89)
WRC Form 366A U.S. NUCLEAR REGULA70RY CopMISSION APPROVED OMS NO. 3150-0104 (6-89) EXPIRES 6/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THis INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD LICENSEE EVENT REPORT (LER) COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND TEXT CONTlWUATION REPORTS MANAGEMENT BRANCH (P-350), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3160-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20603.
FACILITY NAME (1) DOCKET No (2) LER NUMBER (6) PAGE (3)
YEAR SEQ # REV #
or UERMoNT YANKEE NUCLEAR POWER CORPORATION 9 3 -
0 0 5 0 0 0l4 0l4 0l5l0l0l0l2l7l1 TEXT (If more space is required, use additional NRC Form 366A) (17) a Lona Term Corrective Actions
- 1. Vermont Yankee will develop an enhanced trending program for scram times and develop indicators to provide predictive maintenance.
- 2. Prior to the next rod pattern exchange, which is expected to occur in June 1993, the Control Rod Scram Testing and Data Reduction Procedure will be revised to ensure management expectations are met.
- 3. During the next rod pattern exchange scheduled for June, 50% of the control rod drives will be tested to gather further data associated with Control Rod Drive performance.
- 4. Corrective Action Reports (CAR's) will be generated in accordance with Vermont Yankee's Corrective Action Program. This willinclude an assessment of any potential changes or enhancements to TS.
The scheduled date for completing the Corrective Action reports is 7/15/93.
- 5. A Nuclear Network entry will be made summarizing this event.
ADDITIONAL INFORMATION No similar events have been reported to the Commission in the last five years.
The Scram Solenoid Pilot Valves that were rebuilt are ASCO Model HVA 90-405-2A (EliS=FSV) r t
I WRC Form 366 r (6-89)
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