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Category:LICENSEE EVENT REPORT (SEE ALSO AO
MONTHYEARML20024J2471994-10-0606 October 1994 LER 94-009-00:on 940909,EDG G-02 Inadvertently Started & Station Battery Charger D-08 Tripped Off Due to Blown Fuse. Caused by Inadequate Procedure.Blown Fuse Replaced & Electrical Distribution Sys Restored to normal.W/941006 Ltr ML20029C8511994-04-22022 April 1994 LER 94-001-00:on 940323,identified That Feedwater Flow May Have Been Underestimated Since Beginning of Operating Cycle. Caused by Degradation of Signals from Transducers.Transducer replaced.W/940422 Ltr ML20044E5571993-05-17017 May 1993 LER 92-009-01:on 921012,identified That Ccws Surge Tank Vent Valves Outside Design Basis Due to Oversight During Original Design of CCW Sys.Proposes to Replace Radiation Detector & Associated Circuitry W/Dedicated safety-related Sys ML20044E6221993-05-17017 May 1993 LER 93-006-00:on 930416,discovered That Outside CIV Not Leak Tested,Per TS 15.4.4.III.D Requirements Due to Review on 840202,recommending That Valve Be Tested During RHR Hydrostatic Testing.Subj Valve replaced.W/930517 Ltr ML20044D8811993-05-14014 May 1993 LER 93-005-00:on 930415,containment Accident Fan Time Delay Relay 1-TDR-26 (Turbine Bldg Cooler Svc Water Inlet Valve 1SW-2880) Unexpectedly Closed.Caused by Failure to Recognize Presence of Relay in Contact.Function Changed ML20044D2061993-05-10010 May 1993 LER 93-003-00:on 930328,Point Beach Unit 2 Tripped Due to Surveillance Testing Problems.Test Procedures Can Trip Unit Due to Equipment or Human Failure.Failure Tests Delayed Until Unit 1 & Knpp Restored to power.W/930510 Ltr ML20024H2151991-05-21021 May 1991 LER 91-003-00:on 910429,charging Sys Check Valve 1-370 Discovered W/Leakage in Excess of Limits Due to Worn Disc Arm Bushing Steps.Worn Disc Arm Bushing Steps Cladded W/ E308 Weld Matl & Hand Filed to Design contour.W/910521 Ltr ML20029C2101991-03-20020 March 1991 LER 91-002-01:on 901009,inadvertent Start of Auxiliary Feedwater Pump Occurred.Caused by Inadequate Test Procedures.Auxiliary Feedwater Pump Secured & Maint Work Request Mwr 904517 initiated.W/910320 Ltr ML20029C1141991-03-12012 March 1991 LER 91-010-01:on 900816,axial Flux Differential Outside Tech Specs Limits Due to Malfunction of Turbine Electrohydraulic Governor Control.Operator Training Revised. W/910319 Ltr ML20028H0321990-09-27027 September 1990 LER 90-011-00:on 900829,low Net Positive Suction Head to Containment Spray Pumps W/Eccs in Recirculation Mode Occurred.Caused by Procedural Deficiency.Temporary Procedure Changes initiated.W/900927 Ltr ML20043G2011990-06-0808 June 1990 LER 90-005-00:on 900510,steam Generator lo-lo Level Reactor Trip Occurred During Cold Shutdown.Caused by Inadequate Warning Sign Posting.Nonconformance Rept Written to Document Event & Recommend evaluation.W/900608 Ltr ML20042G7761990-05-0909 May 1990 LER 90-003-00:on 900409,determined That Piping & Supports in Fuel Oil Pumphouse Could Not Be Demonstrated to Perform Support Functions.Caused by Design Base Not Sufficiently Documented.Mod Performed to Support Fuel Oil Piping ML20042G7791990-05-0808 May 1990 LER 90-004-00:on 900404,single Failure Potential in Safeguards Switchgear B03/B04 Tie Breaker Discovered & Could Have Resulted in Failure of Diesel Generator.Control Power Fuses for Tie Breakers Removed ML20042F5361990-05-0404 May 1990 LER 90-001-00:on 900405,auxiliary Feed Pump Inadvertently Started.Caused by Inadequate Design.Schematic Push to Test Lamp Circuitry Will Be Added to Elementary Wiring Diagrams & Personnel Briefed on Potential circuitry.W/900504 Ltr ML20042F1971990-05-0202 May 1990 LER 90-002-00:on 900402,main Steam Safety Valve 1-MS-2013 Failed to Relieve Setpoint During Tech Spec Testing.Caused by Personnel Error During Setpoint Adjustment.Safety Valves 1-MS-2011,1-MS-2006 & 1-MS-2008 restored.W/900502 Ltr ML20011D5131989-12-19019 December 1989 LER 89-010-00:on 891120,auxiliary Feedwater Flow Transmitters Inadvertently Isolated.Caused by Error in Approved Procedure & Personnel Cognitive Error.Unit 1 Transmitters Valved Back Into Svc immediately.W/891219 Ltr ML19351A6721989-12-15015 December 1989 LER 89-009-00:on 891115,unexpected Steam Generator a lo-lo Level & Steam Generator B lo-lo Level Reactor Trip Signals Experienced.Caused by Installation of Analog Signal Generator.Procedures revised.W/891215 Ltr ML19332F7011989-12-11011 December 1989 LER 89-008-01:on 890910,ATWS Mitigating Actuation Circuitry Automatically Bypassed at About 42% Reactor Power.Caused by Less than Adequate Tech Spec Change.Power Descension to 38% initiated.W/891211 Ltr ML19332E7221989-12-0707 December 1989 LER 89-009-00:on 891107,D05 & D06 Station Batteries Declared Inoperable.Caused by Original Design Deficiency.Mod Completed to Restore Battery D05 to Operable Status by Replacing Eight nonsafety-related breakers.W/891207 Ltr ML19332E8921989-12-0404 December 1989 LER 89-008-00:on 891103,during Refueling,Contractor Personnel Generated False Trip Signal While Investigating Wiring Discrepancy in Reactor Protection Sys Instrument Racks.Caused by Labeling Error.Supply changed.W/891204 Ltr ML19332F0901989-11-28028 November 1989 LER 89-003-01:on 890712,tank B Level Channel 2LE-934 Began to Indicate Spuriously.Caused by Moisture Intrusion Between Halar Insulator & Sensing Rod.Level Detector Replaced & Channel Reestablished for Accumulator Tank B.W/891128 Ltr ML19332C8411989-11-22022 November 1989 LER 89-007-00:on 891027,Train a Safety Injection Signal Generated During Installation of Mod in Containment High Pressure Circuit.Caused by Inadequate Installation Procedure.Procedure changed.W/891122 Ltr ML19327C2001989-11-14014 November 1989 LER 89-006-01:on 891015,steam Generator Tubes Found Degraded,W/Undefined Signal & W/Axial Indications in Tubesheet Area.Degradation Caused by Time.Affected Tubes Plugged or Preventively sleeved.W/891114 Ltr ML19327C0651989-11-0606 November 1989 LER 89-005-00:on 891006,intermediate Range High Level Trip Signal Unexpectedly Generated During Course of Routine Source Range Channel Calibr.Caused by Loose Connection of Input/Output Cable.Connection tightened.W/891106 Ltr ML19327B3061989-10-19019 October 1989 LER 89-008-00:on 890910,ATWS Mitigating Actuation Circuitry Automatically Bypassed at About 42% Reactor Power, Disenabling Sys.Caused by High Tech Spec Setpoint.Enable/ Disable Setpoint Reset to 30%.W/891019 Ltr ML18041A1611987-11-16016 November 1987 LER 87-004-01:on 870515,voltage Lost on Red Instrument Bus Resulting in Reactor Protection Sys Actuation.Caused by Excessive Current Demand by ferro-resonant Circuit.Plant Mods to Load Bank Proposed ML18041A1341986-07-0303 July 1986 LER 86-003-00:on 860603,reactor Trip Occurred Due to Loss of Power on White Instrument Bus.Caused by Trip of White Inverter Output Breaker.Procedures for Placing Inverter on Line Will Be revised.W/860703 Ltr ML20028E3551983-01-13013 January 1983 LER 82-029/03L-0:on 821216,automatic Monitoring & Alarm Program Constant Found Incorrect.Caused by Unknown Personnel W/Access to on-line Computer.Value of Constant Restored & Control Rods Alignment Verified ML20028E2381983-01-13013 January 1983 LER 82-028/03L-0:on 821215,routine Test on Fire Detection Sys Found Panel D407 Which Monitors Unit 1 Rod Drive Room Inoperable.Caused by Blown Fuse.Fuse & Indication Lights Replaced on 821215.Detection Sys Undergoing Design Review ML20028E1791983-01-13013 January 1983 Updated LER 82-020/01X-1:on 821102,while Performing Type B & C Leakage Tests of Containment Penetrations & Isolation Valves,One Valve Had Leakage Exceeding Limit.Cause Not Stated.Valve Clapper & Seat Lapped ML20028E3031983-01-11011 January 1983 LER 82-027/03L-0:on 821211,operator Noted That Steam Generator Pressure Transmitter 1PT-469 Indicated Higher than Other Channels.Caused by Frozen Sensing Line Due to Inadequate Interim Piping Insulation ML20028E3211983-01-10010 January 1983 Updated LER 82-017/01X-2:on 821030,w/unit Shut Down for Refueling,Eddy Current Exam of Steam Generator Tubes Indicated Four Tubes in Steam Generator a & Three Tubes in Steam Generator B Exceeded Plugging Limit.Caused by Caustic ML20028C2431982-12-27027 December 1982 LER 82-020/01T-0:on 821103,following Type B & C Leak Rate Tests,Total as-measured Leakage Exceeded Tech Spec Limit, Causing Reactor Coolant Pump Component Cooling Water to Have Excessive Leakage.Cause Not Stated.Clapper & Seat Lapped ML20023B3251982-12-10010 December 1982 Updated LER 82-017/01T-1:on 821030,verified That Indications for Four Steam Generator a Tubes & Three Steam Generator B Tubes Exceeded 40% Plugging Limit During Eddy Current Exam on 821026-30.Cause Not Stated.Tubes Mechanically Plugged ML20028B4151982-11-15015 November 1982 LER 82-017/01T-0:on 821030,four Tubes in Steam Generator a & Three Tubes in Steam Generator B Indicated Degradation Greater than 40% Plugging Limit.Caused by Intergranular Attack.Tubes Mechanically Plugged ML20028A0371982-11-0505 November 1982 LER 82-008/03L-0:on 821006,low Steam Line Pressure Setting for Pressure Instrument 2PT-478 Found Lower than Allowed by Tech Specs.Caused by Bumping of Setpoint Adjustment Knob.Instrument Tested & Realigned ML20027D6821982-11-0303 November 1982 LER 82-018/01T-0:on 821015,incorrect Instrument Bus Supply Shifted to Alternate Supply Following Rept of Fire in Supply Breaker for 1GYO4 Motor Generator Set,Causing Loss of Redundancy on Containment Pressure Indicator 1PT-950 ML20052G4501982-05-12012 May 1982 LER 82-002/01T-0:on 820428,during Eddy Current Exam, Discovered Abnormal Degradation in Fuel Cladding,Rcpb & Primary Containment.Seludge Lancing Will Be Performed ML20052G3701982-05-0707 May 1982 LER 82-009/03L-0:on 820408,4.16-kV Safeguards Undervoltage Relays Did Not Meet 0-volt Time Delay Spec.Caused by Manufacturer Characteristic Curves.Relays Not Capable of Less than 0.38-s.Tech Spec Change Requested on 820427 ML20052G3831982-05-0707 May 1982 LER 82-011/03L-0:on 820415,during Biweekly Calibr Check ICP 2.1 of Reactor Protective Sys Functions,Overpower Delta T Setpoint 2 for Channel 2 Found Less Conservative than Tech Spec Limit.Caused by Setpoint Drift in Impulse Summer Unit ML20052G6331982-05-0707 May 1982 LER 82-010/03L-0:on 820414,ICP 2.9 Found Not to Provide for Proper Unblocking of Source Range High Flux Reactor Trip Over Small Range of Instrument Readings.Caused by Failure to Identify Subtle Procedural Flow.Procedure to Be Revised ML20052B4521982-04-23023 April 1982 LER 82-008/03L-0:on 820323,minor Installation Defects Noted on Four of Six Containment Pressure Transmitters Installed as TMI Response Mod.Caused by Backfit Contractor QC Program Breakdown ML20050B2661982-03-25025 March 1982 LER 82-006/01T-0:on 820311,type B & C Valve Leakage Tests Exceeded Tech Spec Limits.Caused by Corrosion.Svc Air Check Valves Disc Replaced & Valve Cover Remachined ML20041F4861982-03-0808 March 1982 LER 82-005/01T-01:on 820222,poison Test Samples & Two Fuel Assemblies W/Less than 1-yr Cooling Period Found Placed Next to Divider Wall in Spent Fuel Pool.Caused by Tech Spec Misinterpretation ML20041E4911982-03-0404 March 1982 LER 82-004/03L-0:on 820206,during Inservice Testing, Differential Pressure Instrument 4007 for Auxiliary Feed Pump P38A Found Isolated.Probably Caused by Failure to Return Instrument to Svc Following Calibr ML20041E6131982-03-0202 March 1982 LER 82-003/01T-0:on 820217,during Surveillance Testing, Emergency Diesel Generator 3D Failed to Operate.Caused by Sticking Shutdown Solenoid Plunger on Woodward Type UG8 Governor.Solenoid Cleaned,Checked & Generator Tested ML20049H6981982-02-23023 February 1982 LER 82-001/03L-0:on 820203,boric Acid Heat Tracing Circuit P-42 Found Inoperable.Caused by Failed Thermon Type 4 Circuit Controller.Circuit Controller Replaced ML20040G6811982-02-0505 February 1982 LER 82-001/03L-0:on 820107,steam Generator Pressure Sensing Lines Discovered Frozen on a Steam Generator.Caused by Inadequate Freeze Protection & Extremely Cold Weather.Addl Heat Lamps Installed ML20040G5801982-02-0505 February 1982 LER 82-002/03L-0:on 820112,during Hot shutdown,1PT-469 Steam Generator Pressure Transmitter Isolated by Maint Personnel Due to Leaking Coupling.Pressure Sensing Tubing Showed Signs of Steam Leak Due to Freezing ML20040D3791982-01-18018 January 1982 LER 81-020/03L-0:on 811219,frozen Sensing Line Caused High Indication of Steam Generator Pressure Instrument 1PT-482. Caused by Incomplete Insulation of Line & by Cold Weather. Instrument Placed in Tripped Position & Tubing Thawed 1994-04-22
[Table view] Category:RO)
MONTHYEARML20024J2471994-10-0606 October 1994 LER 94-009-00:on 940909,EDG G-02 Inadvertently Started & Station Battery Charger D-08 Tripped Off Due to Blown Fuse. Caused by Inadequate Procedure.Blown Fuse Replaced & Electrical Distribution Sys Restored to normal.W/941006 Ltr ML20029C8511994-04-22022 April 1994 LER 94-001-00:on 940323,identified That Feedwater Flow May Have Been Underestimated Since Beginning of Operating Cycle. Caused by Degradation of Signals from Transducers.Transducer replaced.W/940422 Ltr ML20044E5571993-05-17017 May 1993 LER 92-009-01:on 921012,identified That Ccws Surge Tank Vent Valves Outside Design Basis Due to Oversight During Original Design of CCW Sys.Proposes to Replace Radiation Detector & Associated Circuitry W/Dedicated safety-related Sys ML20044E6221993-05-17017 May 1993 LER 93-006-00:on 930416,discovered That Outside CIV Not Leak Tested,Per TS 15.4.4.III.D Requirements Due to Review on 840202,recommending That Valve Be Tested During RHR Hydrostatic Testing.Subj Valve replaced.W/930517 Ltr ML20044D8811993-05-14014 May 1993 LER 93-005-00:on 930415,containment Accident Fan Time Delay Relay 1-TDR-26 (Turbine Bldg Cooler Svc Water Inlet Valve 1SW-2880) Unexpectedly Closed.Caused by Failure to Recognize Presence of Relay in Contact.Function Changed ML20044D2061993-05-10010 May 1993 LER 93-003-00:on 930328,Point Beach Unit 2 Tripped Due to Surveillance Testing Problems.Test Procedures Can Trip Unit Due to Equipment or Human Failure.Failure Tests Delayed Until Unit 1 & Knpp Restored to power.W/930510 Ltr ML20024H2151991-05-21021 May 1991 LER 91-003-00:on 910429,charging Sys Check Valve 1-370 Discovered W/Leakage in Excess of Limits Due to Worn Disc Arm Bushing Steps.Worn Disc Arm Bushing Steps Cladded W/ E308 Weld Matl & Hand Filed to Design contour.W/910521 Ltr ML20029C2101991-03-20020 March 1991 LER 91-002-01:on 901009,inadvertent Start of Auxiliary Feedwater Pump Occurred.Caused by Inadequate Test Procedures.Auxiliary Feedwater Pump Secured & Maint Work Request Mwr 904517 initiated.W/910320 Ltr ML20029C1141991-03-12012 March 1991 LER 91-010-01:on 900816,axial Flux Differential Outside Tech Specs Limits Due to Malfunction of Turbine Electrohydraulic Governor Control.Operator Training Revised. W/910319 Ltr ML20028H0321990-09-27027 September 1990 LER 90-011-00:on 900829,low Net Positive Suction Head to Containment Spray Pumps W/Eccs in Recirculation Mode Occurred.Caused by Procedural Deficiency.Temporary Procedure Changes initiated.W/900927 Ltr ML20043G2011990-06-0808 June 1990 LER 90-005-00:on 900510,steam Generator lo-lo Level Reactor Trip Occurred During Cold Shutdown.Caused by Inadequate Warning Sign Posting.Nonconformance Rept Written to Document Event & Recommend evaluation.W/900608 Ltr ML20042G7761990-05-0909 May 1990 LER 90-003-00:on 900409,determined That Piping & Supports in Fuel Oil Pumphouse Could Not Be Demonstrated to Perform Support Functions.Caused by Design Base Not Sufficiently Documented.Mod Performed to Support Fuel Oil Piping ML20042G7791990-05-0808 May 1990 LER 90-004-00:on 900404,single Failure Potential in Safeguards Switchgear B03/B04 Tie Breaker Discovered & Could Have Resulted in Failure of Diesel Generator.Control Power Fuses for Tie Breakers Removed ML20042F5361990-05-0404 May 1990 LER 90-001-00:on 900405,auxiliary Feed Pump Inadvertently Started.Caused by Inadequate Design.Schematic Push to Test Lamp Circuitry Will Be Added to Elementary Wiring Diagrams & Personnel Briefed on Potential circuitry.W/900504 Ltr ML20042F1971990-05-0202 May 1990 LER 90-002-00:on 900402,main Steam Safety Valve 1-MS-2013 Failed to Relieve Setpoint During Tech Spec Testing.Caused by Personnel Error During Setpoint Adjustment.Safety Valves 1-MS-2011,1-MS-2006 & 1-MS-2008 restored.W/900502 Ltr ML20011D5131989-12-19019 December 1989 LER 89-010-00:on 891120,auxiliary Feedwater Flow Transmitters Inadvertently Isolated.Caused by Error in Approved Procedure & Personnel Cognitive Error.Unit 1 Transmitters Valved Back Into Svc immediately.W/891219 Ltr ML19351A6721989-12-15015 December 1989 LER 89-009-00:on 891115,unexpected Steam Generator a lo-lo Level & Steam Generator B lo-lo Level Reactor Trip Signals Experienced.Caused by Installation of Analog Signal Generator.Procedures revised.W/891215 Ltr ML19332F7011989-12-11011 December 1989 LER 89-008-01:on 890910,ATWS Mitigating Actuation Circuitry Automatically Bypassed at About 42% Reactor Power.Caused by Less than Adequate Tech Spec Change.Power Descension to 38% initiated.W/891211 Ltr ML19332E7221989-12-0707 December 1989 LER 89-009-00:on 891107,D05 & D06 Station Batteries Declared Inoperable.Caused by Original Design Deficiency.Mod Completed to Restore Battery D05 to Operable Status by Replacing Eight nonsafety-related breakers.W/891207 Ltr ML19332E8921989-12-0404 December 1989 LER 89-008-00:on 891103,during Refueling,Contractor Personnel Generated False Trip Signal While Investigating Wiring Discrepancy in Reactor Protection Sys Instrument Racks.Caused by Labeling Error.Supply changed.W/891204 Ltr ML19332F0901989-11-28028 November 1989 LER 89-003-01:on 890712,tank B Level Channel 2LE-934 Began to Indicate Spuriously.Caused by Moisture Intrusion Between Halar Insulator & Sensing Rod.Level Detector Replaced & Channel Reestablished for Accumulator Tank B.W/891128 Ltr ML19332C8411989-11-22022 November 1989 LER 89-007-00:on 891027,Train a Safety Injection Signal Generated During Installation of Mod in Containment High Pressure Circuit.Caused by Inadequate Installation Procedure.Procedure changed.W/891122 Ltr ML19327C2001989-11-14014 November 1989 LER 89-006-01:on 891015,steam Generator Tubes Found Degraded,W/Undefined Signal & W/Axial Indications in Tubesheet Area.Degradation Caused by Time.Affected Tubes Plugged or Preventively sleeved.W/891114 Ltr ML19327C0651989-11-0606 November 1989 LER 89-005-00:on 891006,intermediate Range High Level Trip Signal Unexpectedly Generated During Course of Routine Source Range Channel Calibr.Caused by Loose Connection of Input/Output Cable.Connection tightened.W/891106 Ltr ML19327B3061989-10-19019 October 1989 LER 89-008-00:on 890910,ATWS Mitigating Actuation Circuitry Automatically Bypassed at About 42% Reactor Power, Disenabling Sys.Caused by High Tech Spec Setpoint.Enable/ Disable Setpoint Reset to 30%.W/891019 Ltr ML18041A1611987-11-16016 November 1987 LER 87-004-01:on 870515,voltage Lost on Red Instrument Bus Resulting in Reactor Protection Sys Actuation.Caused by Excessive Current Demand by ferro-resonant Circuit.Plant Mods to Load Bank Proposed ML18041A1341986-07-0303 July 1986 LER 86-003-00:on 860603,reactor Trip Occurred Due to Loss of Power on White Instrument Bus.Caused by Trip of White Inverter Output Breaker.Procedures for Placing Inverter on Line Will Be revised.W/860703 Ltr ML20028E3551983-01-13013 January 1983 LER 82-029/03L-0:on 821216,automatic Monitoring & Alarm Program Constant Found Incorrect.Caused by Unknown Personnel W/Access to on-line Computer.Value of Constant Restored & Control Rods Alignment Verified ML20028E2381983-01-13013 January 1983 LER 82-028/03L-0:on 821215,routine Test on Fire Detection Sys Found Panel D407 Which Monitors Unit 1 Rod Drive Room Inoperable.Caused by Blown Fuse.Fuse & Indication Lights Replaced on 821215.Detection Sys Undergoing Design Review ML20028E1791983-01-13013 January 1983 Updated LER 82-020/01X-1:on 821102,while Performing Type B & C Leakage Tests of Containment Penetrations & Isolation Valves,One Valve Had Leakage Exceeding Limit.Cause Not Stated.Valve Clapper & Seat Lapped ML20028E3031983-01-11011 January 1983 LER 82-027/03L-0:on 821211,operator Noted That Steam Generator Pressure Transmitter 1PT-469 Indicated Higher than Other Channels.Caused by Frozen Sensing Line Due to Inadequate Interim Piping Insulation ML20028E3211983-01-10010 January 1983 Updated LER 82-017/01X-2:on 821030,w/unit Shut Down for Refueling,Eddy Current Exam of Steam Generator Tubes Indicated Four Tubes in Steam Generator a & Three Tubes in Steam Generator B Exceeded Plugging Limit.Caused by Caustic ML20028C2431982-12-27027 December 1982 LER 82-020/01T-0:on 821103,following Type B & C Leak Rate Tests,Total as-measured Leakage Exceeded Tech Spec Limit, Causing Reactor Coolant Pump Component Cooling Water to Have Excessive Leakage.Cause Not Stated.Clapper & Seat Lapped ML20023B3251982-12-10010 December 1982 Updated LER 82-017/01T-1:on 821030,verified That Indications for Four Steam Generator a Tubes & Three Steam Generator B Tubes Exceeded 40% Plugging Limit During Eddy Current Exam on 821026-30.Cause Not Stated.Tubes Mechanically Plugged ML20028B4151982-11-15015 November 1982 LER 82-017/01T-0:on 821030,four Tubes in Steam Generator a & Three Tubes in Steam Generator B Indicated Degradation Greater than 40% Plugging Limit.Caused by Intergranular Attack.Tubes Mechanically Plugged ML20028A0371982-11-0505 November 1982 LER 82-008/03L-0:on 821006,low Steam Line Pressure Setting for Pressure Instrument 2PT-478 Found Lower than Allowed by Tech Specs.Caused by Bumping of Setpoint Adjustment Knob.Instrument Tested & Realigned ML20027D6821982-11-0303 November 1982 LER 82-018/01T-0:on 821015,incorrect Instrument Bus Supply Shifted to Alternate Supply Following Rept of Fire in Supply Breaker for 1GYO4 Motor Generator Set,Causing Loss of Redundancy on Containment Pressure Indicator 1PT-950 ML20052G4501982-05-12012 May 1982 LER 82-002/01T-0:on 820428,during Eddy Current Exam, Discovered Abnormal Degradation in Fuel Cladding,Rcpb & Primary Containment.Seludge Lancing Will Be Performed ML20052G3701982-05-0707 May 1982 LER 82-009/03L-0:on 820408,4.16-kV Safeguards Undervoltage Relays Did Not Meet 0-volt Time Delay Spec.Caused by Manufacturer Characteristic Curves.Relays Not Capable of Less than 0.38-s.Tech Spec Change Requested on 820427 ML20052G3831982-05-0707 May 1982 LER 82-011/03L-0:on 820415,during Biweekly Calibr Check ICP 2.1 of Reactor Protective Sys Functions,Overpower Delta T Setpoint 2 for Channel 2 Found Less Conservative than Tech Spec Limit.Caused by Setpoint Drift in Impulse Summer Unit ML20052G6331982-05-0707 May 1982 LER 82-010/03L-0:on 820414,ICP 2.9 Found Not to Provide for Proper Unblocking of Source Range High Flux Reactor Trip Over Small Range of Instrument Readings.Caused by Failure to Identify Subtle Procedural Flow.Procedure to Be Revised ML20052B4521982-04-23023 April 1982 LER 82-008/03L-0:on 820323,minor Installation Defects Noted on Four of Six Containment Pressure Transmitters Installed as TMI Response Mod.Caused by Backfit Contractor QC Program Breakdown ML20050B2661982-03-25025 March 1982 LER 82-006/01T-0:on 820311,type B & C Valve Leakage Tests Exceeded Tech Spec Limits.Caused by Corrosion.Svc Air Check Valves Disc Replaced & Valve Cover Remachined ML20041F4861982-03-0808 March 1982 LER 82-005/01T-01:on 820222,poison Test Samples & Two Fuel Assemblies W/Less than 1-yr Cooling Period Found Placed Next to Divider Wall in Spent Fuel Pool.Caused by Tech Spec Misinterpretation ML20041E4911982-03-0404 March 1982 LER 82-004/03L-0:on 820206,during Inservice Testing, Differential Pressure Instrument 4007 for Auxiliary Feed Pump P38A Found Isolated.Probably Caused by Failure to Return Instrument to Svc Following Calibr ML20041E6131982-03-0202 March 1982 LER 82-003/01T-0:on 820217,during Surveillance Testing, Emergency Diesel Generator 3D Failed to Operate.Caused by Sticking Shutdown Solenoid Plunger on Woodward Type UG8 Governor.Solenoid Cleaned,Checked & Generator Tested ML20049H6981982-02-23023 February 1982 LER 82-001/03L-0:on 820203,boric Acid Heat Tracing Circuit P-42 Found Inoperable.Caused by Failed Thermon Type 4 Circuit Controller.Circuit Controller Replaced ML20040G6811982-02-0505 February 1982 LER 82-001/03L-0:on 820107,steam Generator Pressure Sensing Lines Discovered Frozen on a Steam Generator.Caused by Inadequate Freeze Protection & Extremely Cold Weather.Addl Heat Lamps Installed ML20040G5801982-02-0505 February 1982 LER 82-002/03L-0:on 820112,during Hot shutdown,1PT-469 Steam Generator Pressure Transmitter Isolated by Maint Personnel Due to Leaking Coupling.Pressure Sensing Tubing Showed Signs of Steam Leak Due to Freezing ML20040D3791982-01-18018 January 1982 LER 81-020/03L-0:on 811219,frozen Sensing Line Caused High Indication of Steam Generator Pressure Instrument 1PT-482. Caused by Incomplete Insulation of Line & by Cold Weather. Instrument Placed in Tripped Position & Tubing Thawed 1994-04-22
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARNPL-99-0569, Monthly Operating Repts for Sept 1999 for Pbnp,Units 1 & 2. with1999-09-30030 September 1999 Monthly Operating Repts for Sept 1999 for Pbnp,Units 1 & 2. with ML20212D5961999-09-15015 September 1999 Safety Evaluation Supporting Licensee IPEEE Process.Plant Has Met Intent of Suppl 4 to GL 88-20 NPL-99-0051, Monthly Operating Repts for Aug 1999 for Pbnp,Units 1 & 2. with1999-08-31031 August 1999 Monthly Operating Repts for Aug 1999 for Pbnp,Units 1 & 2. with NPL-99-0449, Monthly Operating Repts for July 1999 for Pbnp,Units 1 & 2. with1999-07-31031 July 1999 Monthly Operating Repts for July 1999 for Pbnp,Units 1 & 2. with ML20196J4251999-06-30030 June 1999 Safety Evaluation Authorizing Proposed Alternatives Described in Relief Requests VRR-01,ROJ-16,PRR-01 & VRR-02 ML20209D2691999-06-30030 June 1999 Monthly Operating Repts for June 1999 for Pbnps,Units 1 & 2 ML20196F3341999-06-22022 June 1999 Safety Evaluation for Implementation of 422V+ Fuel Assemblies at Pbnp Units 1 & 2 ML20195F9781999-06-10010 June 1999 Unit 2 Refueling 23 Inservice Insp Summary Rept for Form NIS-1 ML20209D2751999-05-31031 May 1999 Revised MORs for May 1999 for Pbnps,Units 1 & 2 NPL-99-0328, Monthly Operating Repts for May 1999 for Pbnp,Units 1 & 2. with1999-05-31031 May 1999 Monthly Operating Repts for May 1999 for Pbnp,Units 1 & 2. with NPL-99-0273, Monthly Operating Repts for Apr 1999 for Point Beach Nuclear Plant,Units 1 & 2.With1999-04-30030 April 1999 Monthly Operating Repts for Apr 1999 for Point Beach Nuclear Plant,Units 1 & 2.With ML20196F3521999-04-30030 April 1999 Non-proprietary WCAP-14788, W Revised Thermal Design Procedure Instrument Uncertainty Methodology for Wepc Point Beach Units 1 & 2 (Fuel Upgrade & Uprate to 1656 Mwt - NSSS Power) NPL-99-0193, Monthly Operating Repts for Mar 1999 for Pbnp,Units 1 & 2. with1999-03-31031 March 1999 Monthly Operating Repts for Mar 1999 for Pbnp,Units 1 & 2. with NPL-99-0134, Monthly Operating Repts for Feb 1999 for Pbnp,Units 1 & 2. with1999-02-28028 February 1999 Monthly Operating Repts for Feb 1999 for Pbnp,Units 1 & 2. with ML20207D6751999-02-22022 February 1999 Assessment of Design Info on Piping Restraints for Point Beach Nuclear Plant,Units 1 & 2.Staff Concludes That Licensee Unable to Retrieve Original Analyses That May Have Been Performed to Justify Removal of Shim Collars ML20206R9001999-01-13013 January 1999 SER Accepting Nuclear Quality Assurance Program Changes for Point Beach Nuclear Plant,Units 1 & 2 NPL-99-0008, Monthly Operating Repts for Dec 1998 for Pbnp,Units 1 & 2. with1998-12-31031 December 1998 Monthly Operating Repts for Dec 1998 for Pbnp,Units 1 & 2. with NPL-99-0091, 1998 Annual Results & Data Rept for Pbnps,Units 1 & 2. with1998-12-31031 December 1998 1998 Annual Results & Data Rept for Pbnps,Units 1 & 2. with ML20198C7671998-12-10010 December 1998 Safety Evaluation Accepting Licensee Proposed Alternative to ASME BPV Code,1986 Edition,Section XI Requirement IWA-2232, to Use Performance Demonstration Initiative Program During RPV Third 10-yr ISI for Plant,Unit 2 NPL-98-1006, Monthly Operating Repts for Nov 1998 for Point Beach Nuclear Plant,Units 1 & 2.With1998-11-30030 November 1998 Monthly Operating Repts for Nov 1998 for Point Beach Nuclear Plant,Units 1 & 2.With ML20195J5101998-11-16016 November 1998 Proposed Revs to Section 1.3 of FSAR for Pbnp QA Program ML20198J5941998-11-0303 November 1998 1998 Graded Exercise,Conducted on 981103 NPL-98-0948, Monthly Operating Repts for Oct 1998 for Point Beach Nuclear Plant,Units 1 & 2.With1998-10-31031 October 1998 Monthly Operating Repts for Oct 1998 for Point Beach Nuclear Plant,Units 1 & 2.With NPL-98-0880, Special Rept:On 980913,fire Alarm Control Panels Inoperable for More That Fourteen Days.Troubleshooting of D-401 Panel Following Installation of Replacement Batteries Revealed No Apparent Cause for Spurious Alarms.Panel D-401 Restored1998-10-21021 October 1998 Special Rept:On 980913,fire Alarm Control Panels Inoperable for More That Fourteen Days.Troubleshooting of D-401 Panel Following Installation of Replacement Batteries Revealed No Apparent Cause for Spurious Alarms.Panel D-401 Restored ML20154M9121998-10-14014 October 1998 Unit 1 Refueling 24 Repair/Replacement Summary Rept for Form NIS-2 ML20154L6751998-10-14014 October 1998 Unit 1 Refueling 24 ISI Summary Rept for Form NIS-1 NPL-98-0826, Monthly Operating Repts for Sept 1998 for Point Beach Nuclear Plant,Units 1 & 2.With1998-09-30030 September 1998 Monthly Operating Repts for Sept 1998 for Point Beach Nuclear Plant,Units 1 & 2.With ML20151W3851998-08-31031 August 1998 Monthly Operating Repts for Aug 1998 for Pbnp Units 1 & 2 NPL-98-0653, Monthly Operating Repts for July 1998 for Point Beach Nuclear Plant,Units 1 & 21998-07-31031 July 1998 Monthly Operating Repts for July 1998 for Point Beach Nuclear Plant,Units 1 & 2 ML20151W4471998-07-31031 July 1998 Corrected Page to MOR for July 1998 for Pbnp Unit 2 ML20151W4541998-07-31031 July 1998 Corrected Page to MOR for July 1998 for Pbnp Unit 1 ML20236Q3161998-07-10010 July 1998 Safety Evaluation Accepting Licensee Proposed Alternative to ASME Code Requirements PTP-3-01 & PTP-3-02 ML20236L6771998-07-0707 July 1998 Safety Evaluation Approving Wepco Implementation Program to Resolve USI A-46 at Point Beach NPP Units 1 & 2 NPL-98-0558, Monthly Operating Repts for June 1998 for Pbnp,Units 1 & 21998-06-30030 June 1998 Monthly Operating Repts for June 1998 for Pbnp,Units 1 & 2 ML20151W4261998-06-30030 June 1998 Corrected Page to MOR for June 1998 for Pbnp Unit 2 ML20151W4221998-05-31031 May 1998 Corrected Page to MOR for May 1998 for Pbnp Unit 2 NPL-98-0481, Monthly Operating Repts for May 1998 for Point Beach Nuclear Plant,Units 1 & 21998-05-31031 May 1998 Monthly Operating Repts for May 1998 for Point Beach Nuclear Plant,Units 1 & 2 ML20151W4011998-04-30030 April 1998 Corrected Page to MOR for April 1998 for Pbnp Unit 2 NPL-98-0356, Monthly Operating Repts for April 1998 for Point Beach Nuclear Plant,Units 1 & 21998-04-30030 April 1998 Monthly Operating Repts for April 1998 for Point Beach Nuclear Plant,Units 1 & 2 ML20217F3131998-04-17017 April 1998 Safety Evaluation Accepting Proposed Alternative to ASME Code for Surface Exam of Nonstructural Seal Welds,For Plant, Unit 1 ML20216D7071998-03-31031 March 1998 Monthly Operating Repts for Mar 1998 for Point Beach Nuclear Plant,Units 1 & 2 ML20151W3981998-03-31031 March 1998 Corrected Page to MOR for March for Pbnp Unit 2 NPL-98-0209, Special Rept Re Fire Barrier Inoperable for Greater than Seven Days.Compensatory Measures Implemented in Accordance W/Fire Protection Program Requirements During Time That Barriers Were Inoperable1998-03-30030 March 1998 Special Rept Re Fire Barrier Inoperable for Greater than Seven Days.Compensatory Measures Implemented in Accordance W/Fire Protection Program Requirements During Time That Barriers Were Inoperable ML20217A8501998-03-19019 March 1998 SER Accepting Proposed Changes Submitted on 980226 by Wiep to Pbnp Final SAR Section 1.8 Which Will Impact Commitments Made in Pbnp QA Program Description.Changes Concern Approval Authority for Procedures & Interviewing Authority ML20216J0101998-03-17017 March 1998 Safety Evaluation Accepting Third 10-yr Inservice Insp Interval Relief Request RR-1-18 for Plant NPL-98-0159, Monthly Operating Repts for Feb 1998 for Point Beach Nuclear Plant,Units 1 & 21998-02-28028 February 1998 Monthly Operating Repts for Feb 1998 for Point Beach Nuclear Plant,Units 1 & 2 ML20151W3891998-02-28028 February 1998 Corrected Page to MOR for Feb 1998 for Pbnp Unit 2 ML20216D7121998-02-28028 February 1998 Revised Corrected MOR for Feb 1998 for Point Beach Nuclear Plant,Unit 2 NPL-98-0084, Monthly Operating Repts for Jan 1998 for Point Beach Nuclear Plant,Units 1 & 21998-01-31031 January 1998 Monthly Operating Repts for Jan 1998 for Point Beach Nuclear Plant,Units 1 & 2 ML20198L1151998-01-0808 January 1998 SER Accepting Licensee Response to GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power-Operated Gate Valves, for Point Beach Nuclear Plant,Units 1 & 2 1999-09-30
[Table view] |
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Electnc i POWER COMPANY i i
231 W Mctgm PO ban 204o. Mwa.*oa WI 53?01 (414)221 2345 L VPNPD-89-596 10 CFR 50.73 !
NRC-09-143 [
Noveinber 14, 1989 i i
U. S. NUCLEAR REGULATORY COMMISSION l Document control Desk :
- Mail Station P1-137 t Washington, D. C. 20555 i t
Gentlemen DOCKET 50-301 i LICENSEE EVENT REPORT 89-006_QA -
DEGRADATION OF STEAM GENERATOR TUBES POINT BEACH NUCLEAR PLANT. UNIT 2 Enclosed is Licensee Event Report 89-006-00 for Point Beach i Nuclear Plant, Unit 2. This report is provided in accordance '
with Technical Specification 15.4.2.A.7(a), "After each inservice' examination, the number of tubes plugged or repaired ;
I, in each steam generator shall be reported.to the Commission as soon as practicable" and 15.4.2.A.7(c), " Reports required by Table 15.4.2-1, ' Steam Generator Tube Inspection', shall .
f provide the information required by Technical Specification 15.4.2.A.7(b) and a description of investigations conducted to determine the cause of the tube degradation and corrective ,
, measures taken to prevent recurrence." LER 89-006-00 is filed l according to the above table under the reporting requirement of 10 CFR 50.73 (a) (2) (ii) .
If any further information is required, please contact us.
l Very truly yours, 0
du C. W. a Vice President Nuclear Power l
l' Enclosure ,
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] vee t,, e e #x.ecreo stemmo= catas ] e,o l l l a .c , ,6 . .. . . = m ., .- , nei Unit 2 was shut down for Refueling 15 on September 22, 1989. Eddy current examination of the steam generator tubes was conducted from October 4 to October 15, 1989, using a digital :aulti-frequency l eddy current system. In the A steam generator hot leg, inspection results indicated 4 tubes degraded equal to or greater than 40% of the wall thickness, one tube with an undefined signal, 20 tubes with axial indications in the tubesheet area, and 2 restricted tubes.
All 27 of these tubes were plugged.
In the B steam generator a total of 7 tubes were degraded equal to or greater than 40% of the tube wall thickness, and 2 tubes had axial indications in the tubesheet area. Six of these tubes were mechanically plugged and the remaining three were included in the ;
sleeving program. A total of 298 tubes were preventively sleeved in the cold leg to address wastage concerns. I The 800 psid leak test revealed 4 mechanically plugged sleeved tubes 4 and two sleeves leaking slightly in the B hot leg while 3 other l tubes showed dampness. One explosively plugged tube and three i sleeved tubes were leaking slightly in the A hot leg. The leaking 1 mechanical plugs were repaired by the plug-in-plug repair and the i others were left as found because of the minimal leakrate (<1 drop /2 min) or the lack of any indications during eddy current 1 testing. The leaking sleeves were left as found as the sleeves are leak limiting by design.
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EVENT DESCRIPTION 800 PSID LEAK CHECK Prior to eddy current inspection on both steam generators, 800 psid secondary to primary leak checks were performed in the hot and cold legs of each steam generator. The checks were performed visually with the aid of remote video equipment. The leak check revealed 3 leaking sleeves and 1 explosive plug in the A steam generator hot leg. In the B steam generator hot leg 4 mechanically plugged sleeved tubes, and two sleeves were noted to be leaking. Also, 3 tubes showed signs of dampness in the B steam generator hot leg. Leakage noted was less than or equal to 1 drop /2 min in all cases.
EDDY CURRENT INSPECTION SCOPE Eddy current inspections began shortly after the leak testing was completed. The eddy current program addressed the following items:
- 1. A 10 percent full-length sample on B S/G and a 9.6% full length sample on A S/G. (Technical Specifications require 3.0%)
- 2. Previously degraded tubes that had not been repaired.
- 3. A 10 percent sample of the tubes which had sleeves installed in the hot leg in each steam generator in 1983.
- 4. One hundred percent of the remaining unsleeved tubes in the hot leg to the first support plate in each steam generator, looking particularly for tube 5heet crevice corrosion.
- 5. A 10 percent sample of tubes which had sleeves installed in 1988 in the cold leg in each steam generator.
- 6. One hundred percent inspection of the unsleeved tubes in the B steam generator from the cold leg tube end to the first support plate for wastage and pitting.
- 7. A 14% sample of the A cold leg unsleeved tubes from the tube end to the first support plate for wastage and pitting. This included all of the peripheral tubes and those tubes in the area where wastage had been noted in previous inspections.
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3f 0l 3 or 0l7 The number of tubes inspected and the extent of the inspections are as follows: '
A Steam Generator Number of Tubes From From '
Extent of Inspection Hot Leg Cold Leg f
Full length 138 Through U-Bend to #6TSPC 20
- 1 TSP to tube end 1420 435 ,
Sleeves 138 12 To Top of Hot Leg Sleeve 138
- 6TSPC to tube end 20 TOTAL 1716 605 B Steam Generator
- Number of Tubes From From i Extent of Inspection Hot Leg Cold Leg ;
Full length 150 Through U-Bend to #6TSPC 21
- 1 TSP to tube end 1512 2229 Sleeves 141 48 To Top of Hot Leg Sleeve 141 '
- 6TSPC to tube end 21 TOTAL 1824 2439 <
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- 1 TSP First support plate
- 6TSPC Sixth support plate cold leg side Inspections from the cold leg side were performed due to concerns '
with cold leg wastage found during the U2R11 outage. As a result of these inspections cold leg sleeves were installed in the B steam -
generator as part of an optional preventive maintenance program.
Steam Generator Mechanical Tube Plug Repair
-During this outage a total of 189 plug-in-plug repairs were made (65 on A, 124 on B) to address industry concerns, described in IE Bulletin 89-01, regarding certain Westinghouse mechanical plugs which were susceptible to intergranualar stress corrosion cracking (IGSCC). One hot leg sleeve plug in the B steam generator was removed and replugged following an unsuccessful plug-in-plt;1 inser-tion attempt in the original plug.
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Point Beach Nuclear Plant e p;o;o;o p p p 3 ;9 __0 [0 l6 ._0 l0 0 ;4 or 0l7 vm m, . e w an..,nw A STEAM GENERATOR TUBES EXCEEDING PLUGGING LIMIT On October 15, 1989, review and verification of all eddy current data for tubes with indications exceeding the plugging limit was completed. A total of 27 tubes were plugged. Four tubes in the unsleeved region of the A steam generator were found having degradation equal to or greater than the plugging limit of 40% of the nominal tube wall thickness (Technical Specification 15.4.2.A 5).
In addition, 20 tubes having axial indications were identified using a magnetic rotating pancake coil (MRPC). Another tube had an undefined signal while two other tubes were restricted and failed to pass a
.650" probe.
The following is a list of the affected tubes:
TUBES THAT WERE PLUGGED Tube Defect Location Cause RSC4 MAI 5.9" ATE HL Crevice Corrosion R15C7 SAI 6.1" ATE HL Crevice Corrosion R18C7 MAI 8.0" ATE HL Crevice Corrosion R20C10 UDI 3.9" ATE HL Crevice Corrosion R37C28 SAI 8.6" ATE HL Crevice Corrosion RIC30 SAI 0.2" ATS HL Wastage R42C31 REST. #5 TSP HL Denting R37C33 78% 7.2" ATE HL Crevice Corrosion R42C33 REST. #5 TSP HL Denting R32C35 90% 8.6" ATE HL Crevice Corrosion R37C40 MAI 4.0" ATE HL Crevice Corrosion R37C52 85% 10.3" ATE HL Crevice Corrosion R39C54 MAI 4.1" ATE HL Crevice Corrosion R33C59 SAI 3.8" ATE HL Crevice Corrosion R33C61 MAI 4.1" ATE HL Crevice Corrosion RSC72 MAI 13.8" ATE HL Crevice Corrosion R31C75 MAI 2.8" ATE HL Crevice Corrosion R35C76 MAI 4.7" ATE HL Crevice Corrosion R6C77 MAI 14.9" ATE HL Crevice Corrosion R8C77 MAI 7.3" ATR HL Crevice Corrosion R9C79 SAI 10" ATR HL Crevice Corrosion R6C80 MAI 6.1" ATE HL Crevice Corrosion R11C84 MAI 2.3" ATE HL Crevice Corrosion R1C85 MAI 3.2" ATE HL Crevice Corrosion R10C85 SAI 1.6" ATE HL Crevice Corrosion R12C86 MAI 3.8" ATE HL Crevice Corrosion R13C89 80% 8.1" ATE HL Crevice Corrosion 1
ATR - Above Tube Roll SAI - Single Axial Indication ATE - Above Tube End MAI - Multiple Axial Indication ATS - Above Tube Sheet REST - Restricted 5 .650" Dia. Probe ;
HL - Hot Leg UDI - Undefined Indication TSP - Tube Support Plate E*d,' ** * *"
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wri . . -- w<=-mu.,nw B STEAM GENERATOR TUBES EXCEEDING THE PLUGGING LIMIT In the B steam generator, 7 tubes were found with indications equal to or greater than the plugging limit of 40% and 2 tubes were found ,
to have axial indications as identified with MRPC. Six of these tubes were plugged, and the remainder (3) were sleeved on the cold leg side.
The following is a list of the affected tubes:
TUBES THAT WERE PLUGGED Tube Defect Location Cause R6C1 48% #1 TSP HL Wastage R6C7 SAI 3.9" ATR HL Crevice Corrosion R17C18 40% #1 TSP CL Wastage R31C19 41% #1 TSP CL Wastage RIC50 80% 4.1" ATE HL Crevice Corrosion R33C78 MAI 2.1" ATE HL Crevice Corrosion TUBES THAT WERE SLEEVED Tube Defect Location Cause R16C35 40% 0.8" ATS CL Wastage R7C50 41% 0.9" ATS CL Wastage R16C51 41% 0.8" ATS CL Wastage ATE - Above Tube End SAI - Single Axial Indication ATS - Above Tube Sheet MAI - Multiple Axial Indication HL - Hot Leg CL - Cold Leg TSP - Tube Support Plate The 1988 data from both steam generators was compared to the 1989 data to determine indication growth rate. The results are as follows:
- 1. In terms of tube wall thickness, degradation percentages and affected steam generator area, the degree of cold leg wastage at the top of the tubesheet in the A steam generator is less than in the B steam generator.
- 2. In the A and B steam generator hot leg, previous indications showed growth rates under 10% since last inspection in 1988.
However, several indications which exceeded the plugging limits have appeared in random locations, g,. o.. .
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- 3. In the B steam generator cold leg, 5 tubes wit'h previous reportable indications required repair. Three of these tubes were included in the sleeving program and two were plugged.
- 4. The rate of indic . tion growth was about 8-10%, which is a slight increase from our 1988 average. -
COLD LEG WASTAGE AND PITTING ,
Tubes in both steam generator cold legs showed signs of being affected by wastage. The B steam generator has been affected more than A. In the B steam generator, 72 tubes (in addition to the 298 sleeved tubes) have indications. In the A steam generator, only '
5 tubes showed indications of this type. Pitting, which has been found at other plants, has not been found at Point Beach.
TUBESHEET CREVICE CORROSION Twenty-four tubes were found in the A steam generator unsleeved portion of the hot leg with signs of crevice corrosion. Three unsleeved tubes were found in the B steam generator hot leg with signs of crevice corrosion. All of these tubes were plugged.
SLEEVED TUBES A total of 339 previously installed sleeves were inspected (150 in A, 189 in B) with no reportable indications in either steam generator. An additional 298 tubes were sleeved in the B steam generator cold leg as a preventive maintenance measure.
PROBE RESTRICTIONS Probe restrictions were noted in both steam generators in the unsleeved regions. In the A steam generator, 66 tubes would not pass a 0.720" probe, 18 of these tubes would not pass a 0.700" probe, and 7 of the 18 tubes would not pass a 0.680" probe. A 0.650" probe was able to go through 3 of these tubes. Two tubes would not pass a .650" probe and were plugged. A .610" diameter probe was used to inspect these tubes and showed no defect. In the B steam generator, 58 tubes would not pass a 0.720" probe, and 17 of these tubes would not pass a 0.700" probe. A 0.680" probe was passed through all of these tubes. No tube had to be plugged in the B steam generator because of unacceptable restrictions. The restrictions in both steam generators appear to be a result of denting at the tube support plates in both generators.
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Point Beach Nuclear Plant n p go;ogo f p p B;9 _ 00;69 0 ;0 01 7 0F 01 7, varf n- . we % mu.nm SLUDGE LANCING Sludge lancing was performed this outage.
154 pounds of sludge was removed from the A steam generator and 102 pounds from the B steam generator. Routine visual checks with fiber optics were made to assecs the cleanliness after lancing. The visual check results were satisfactory.
MINIMIZATION OF TUBE DEGRADATION Other measures continue to be taken to minimize degradation of the steam generator tubes. These include crevice flushing prior to heating up to normal operating temperature and maintaining stricter chemistry controls in accordance with the prescribed guidelines.
PREVENTATIVE MAINTENANCE Wisconsin Electric continues to monitor tube integrity on the hot leg of each steam generator and plug those tubes which exceed cr approach the plugging limit in the Technical Specifications. In the cold legs, we are continuing to plug or sleeve tubes which exceed the plugging limit in the Technical Specifications.
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