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Category:LICENSEE EVENT REPORT (SEE ALSO AO
MONTHYEARML18039A9041999-10-15015 October 1999 LER 99-010-00:on 990917,automatic Reactor Scram on Turbine Stop Valve Closure Occurred.Caused by High Water Level in Main Steam Moisture Separator 2C2.Unit 2C2 Reservoir Level Transmitter & Relays Were Replaced & Tested Satisfactorily ML18039A8981999-10-14014 October 1999 LER 99-009-00:on 990915,manual Reactor Scram Was Noted Due to EHC Leak.Caused by Failure of Stainles Steel Tubing Connection.Removed Damaged Tubing & Connection Plug ML18039A8951999-10-0808 October 1999 LER 99-008-00:on 990905,HPCI Was Inoperable Due to Failed Flow Controller.Caused by Premature Failure of Capacitor 2C3.Replaced Controller & HPCI Sys Was Run IAW Sys Operating Instructions ML18039A8751999-09-30030 September 1999 LER 99-005-00:on 990901,SR for Standby Liquid Control Sampling Was Not Met.Caused by Deficient Procedure for Chemical Addition to Standby Liquid Control.Revised Procedure.With 990930 Ltr ML18039A8201999-07-26026 July 1999 LER 99-004-00:on 990625,facility Core Spray Divisions I & II Inoperable at Same Time Due to Personnel Error.Electrical Supply Breaker to Core Spray Division II Pump 3B Returned to Normal Racked in Position ML18039A8171999-07-20020 July 1999 LER 99-007-00:on 990623,discovered That SR for Monitoring of Primary Containment Oxygen Concentration Had Not Been Met. Caused by Failure of Operators to Adequately Communicate. Required Surveillances Were Performed.With 990720 Ltr ML18039A8161999-07-19019 July 1999 LER 99-006-00:on 990618,noted That Main Steam SRV Exceeded TS Setpoint Tolerance.Caused by Pilot Vlve disc-seat Bonding.Util Replaced All 13 SRV Pilot Cartridges with Cartridges Certified to Be Witin +/-1%.With 990719 Ltr ML18039A8121999-07-12012 July 1999 LER 99-005-00:on 990617,ESF Actuation & HPCI Declared Inoperable.Caused by Personnel Error.Reset HPCI & Returned Sys to Operable Status with 25 Minutes.With 990712 Ltr ML18039A8101999-06-28028 June 1999 LER 99-004-00:on 990530,safety Features Sys Actuations Occurred Due to RPS Trip.Caused by Failure of MG Set AC Drive Motor Starter Contractor Coil.Licensee Placed 2B RPS Bus on Alternate Feed & Half Scram Was Reset ML18039A8011999-06-14014 June 1999 LER 99-001-00:on 990515,automatic Reactor Scram Occurred Due to Tt.Caused by Failure of Mechanical Trip Cylinder to Latch When Hydraulically Reset.Operations Crew Stabilized Reactor Following Scram.With 990614 Ltr ML18039A8021999-06-14014 June 1999 LER 99-002-00:on 990501,SRs for Single CR Withdrawal During Cold SD Were Not Adequately Implemented.Caused by Procedural Inadequacy.Revised Applicable Plant Surveillances.With 990614 Ltr ML18039A8071999-06-14014 June 1999 LER 99-003-00:on 990515,automatic Reactor Scram Due to Turbine Trip Was Noted.Caused by Failure of Mechanical Trip Cylinder to Latch When Hydraulically Reset.Operations Crew Stabilized Reactor Following Scram ML18039A7791999-05-0606 May 1999 LER 99-003-00:on 990408,declared Plant HPCI Sys Inoperable Due to Loose Wire.Caused by Failure to Properly Tighten Screw at Some Time in Past.Loose Wire Was Tightened ML18039A7461999-04-0707 April 1999 LER 99-001-00:on 990308,determined That Two Trains of Standby Gas Treatment (SGT) Were Inoperable.Caused by Trip C SGT Blower Motor Breaker.Initiated Shutdown of Plant,Reset C SGT Blower Motor Breaker & Declared Train Operable ML18039A6951999-02-19019 February 1999 LER 99-002-00:on 990122,LCO Was Not Entered During Calibration Testing of 3D 480 Volt Rmov Board.Caused by Personnel Error.Tva Has Briefed Operations Personnel to Preclude Recurrence of Event.With 990219 Ltr ML18039A6871999-02-12012 February 1999 LER 99-001-00:on 990114,Unit 3 HPCI Was Noted Inoperable. Caused by Oil Leak on Stop Valve.Corrective Maint Was Performed to Repair Oil Leak.With 990212 Ltr ML18039A6671998-12-31031 December 1998 LER 98-004-00:on 981202,SR Intent Was Not Adequately Implemented.Caused by Procedural Inadequacy.Revised Procedures to Provide Proper SR Implementation.With 981231 Ltr ML18039A6471998-12-15015 December 1998 LER 98-007-00:on 981116,unplanned ESF Following Loss of 4kV Unit Board 3B Occurred.Caused by Temporary Energization of Lockout Relay on 4kV Unit Board 3B When Resistor on Relay Monitoring Lamp Circuit Shorted.Replaced Resistor ML18039A6371998-12-0707 December 1998 LER 98-006-00:on 981116,MSSR Valves Exceeded TS Setpoint Tolerance.Caused by Pilot Valve Disc/Seat Bonding. Installed SRV Pressure Switches During Unit 3,cycle 8 Outage.With 981207 Ltr ML18039A6071998-11-12012 November 1998 LER 98-005-00:on 981014,mode Changes Not Allowed by TS 3.0.4 Were Made During Reactor Startup.Caused by TS LCO 3.0.4 Not Being Properly Applied.Training Info Memo Re Proper Application for TS LCO 3.0.4 Was Prepared.With 981112 Ltr ML18039A6031998-11-0404 November 1998 LER 98-004-00:on 981007,primary Containment Allowable Leak Rate Was Exceeded.Caused by Failure of Check Valve to Fully Seat Following Shutdown of Rbbccw Sys for Llrt.Valve Was Retested During Next Refueling Outage.With 981104 Ltr ML18039A5971998-10-28028 October 1998 LER 98-003-00:on 981001,Unit 2 Received Full Automatic Scram from 100% Reactor Power.Caused by Failure of Normally Open Isolation Valve Which Blocked Flow of Stator Cooling Water Through Associated Heat Exchangers.Replaced Failed Valve ML18039A5171998-09-15015 September 1998 LER 98-002-00:on 980816,personnel Observed Both Channels of Rod Block Monitor Sys Bypassed for Cr.Caused by Failure of Gene to Properly Document & Specify Adjustments.Will Implement Necessary Procedure Controls ML18039A3311998-05-0404 May 1998 LER 98-003-00:on 980407,reactor Manually Scrammed to Prevent thermal-hydraulic Instability After Recirculation Pump Runback.Caused by Human Error.Strengthened Controls Associated W/Walkdowns in NEDP-11 ML18039A3141998-04-0909 April 1998 LER 98-002-00:on 980310,ESF Actuation Occurred Due to Failure of Alternate Feeder Breaker Position Switch.Will Continue Testing & Visual Insps on Addl Breaker Position Switches & Will Revise Applicable Maint Instructions ML18039A3101998-04-0707 April 1998 LER 98-001-00:on 980308,ESF Actuations Occurred When 2B RPS Bus Was Transferred to de-energized Source.Caused by Failure of Preparing Clearance to Exercise Proper Attention. 2B RPS Bus Restored to Transformer Source ML18039A3051998-04-0101 April 1998 LER 96-001-00:on 980121,determined That Temp Sensors for Certain HELB May Not Detect All Possible Break Locations. Caused by Differences in Computer Codes Rather than Actual Response.Computer Code Correctly Utilized ML18039A2041997-12-0303 December 1997 LER 97-008-00:on 971104,main Steam Safety/Relief Valves Exceeded TS Setpoint Limit.Caused by Pilot Valve Disc/Seat Bonding.Replaced All 13 Unit 2 Main Steam SRV Pilot Cartridges ML18038B9961997-11-25025 November 1997 LER 97-007-00:on 971028,Unit 2 Automatically Scrammed.Caused by Momentary Pressure Drop in electro-hydraulic Control Sys at Turbine Control Valves.Scram Contactor Replaced ML18038B9931997-11-18018 November 1997 LER 97-006-00:on 971019,declared Unit 2 Hpcis Inoperable. Caused by High Condensate Level in HPCI Turbine Inlet Steam Line Drain Pot.Work Request Initiated ML18038B9861997-11-10010 November 1997 LER 97-005-00:on 971012,ESF Components Were Actuated.Caused by Inadequate Procedure.Cs Pumps Were Secured & Injection Valves Were Closed & Refueling Floor Activities Were Stopped ML18038B9701997-10-0909 October 1997 LER 97-004-00:on 970909,TS Surveillances Were Not Performed During Refueling Outage Timeframe.Caused by Personnel Error. Incorporated Missed Snubber & Vacuum Breaker Surveillances Into Refueling Outage Schedule ML18038B9661997-10-0303 October 1997 LER 97-005-00:on 970824,LCO Was Not Entered When Valve Was Malfunctioning.Caused by Lack of Questioning Attitude by Operations Crew.Involved SROs Were Counseled & Problem Evaluation Rept Will Be Discussed ML18038B9321997-08-0707 August 1997 LER 97-003-00:on 970711,determined That HPCI Turbine Speed Lower than Indicated.Caused by Improper Evaluation of Valve Leak.Work Orders to Troubleshoot HPCI Initiated ML18038B9231997-07-25025 July 1997 LER 97-002-00:on 970626,discovered That Four Surveillance Instructions (Sis) Did Not Fully Test All Relay Logic Combinations.Caused by Personnel Error.Verified Relay Contacts Operable & Revised Applicable SIs.W/970725 Ltr ML18038B8811997-05-14014 May 1997 LER 97-004-00:on 970414,unplanned Manual Start of EDG During Scheduled Redundant Start Test Occurred.Caused by Personnel Error.Edg 3D Shutdown & Returned to pre-event Configuration. W/970514 Ltr ML18038B8801997-05-0808 May 1997 LER 97-002-00:on 970410,HPCI Declared Inoperable.Caused by Personnel Error.Operations Personnel Stopped Instrument Mechanics Testing & Returned HPCI to Standby Readiness. W/970508 Ltr ML18038B8701997-04-29029 April 1997 LER 96-004-02:on 960717,loss of ECCS Division I & Division II Instrumentation Renders ECCS Equipment Inoperable.Caused by Loss of Inverter Output.Failed Components Replaced in Atu Inverter Circuitry & Instrumentation Logic Restored ML18038B8521997-04-0909 April 1997 LER 97-003-00:on 970314,Unit 3 Main Steam SRVs Pilot Cartridges Failed Setpoint Tolerance Bench Tests.Caused by Corrosion Bonding of SRV Pilot Disc/Seat Interface Resulting in Drifting.Main Steam SRV Pilot replaced.W/970409 Ltr ML18038B8511997-04-0909 April 1997 LER 95-003-02:on 950301,Unit 2 Main Steam SRVs Failed Setpoint Acceptance Tests.Caused by Corrosion Bonding of SRV Pilot Disc/Seat Interface Resulting in Upward Setpoint Drift.Valves Currently Being Retested & Recertified ML18038B8481997-04-0909 April 1997 LER 96-004-01:on 960425,Unit 2 SRV Pilot Cartridges Failed Setpoint Acceptance Tests.Caused by SRV Pilot Disc/Seat Bonding Resulting in SRV Setpoints Deviating.Valves Currently Being Retested & Recertified ML18038B8451997-04-0909 April 1997 LER 96-008-01:on 961101,Unit 2 Main Steam SRV Pilot Cartridges Failed Setpoint Tolerence Bench Tests.Caused by SRV Pilot Disc/Seat Bonding Resulting in SRV Setpoints.Srv Pilot Cartridges replaced.W/970409 Ltr ML18038B8551997-04-0404 April 1997 LER 97-001-00:on 970305,loss of Offsite Power on Unit 3 During Refueling Outage Resulted from Shorted Component. Replaced Relays Involved in Event W/Less Sensitive Relays ML18038B8441997-03-26026 March 1997 LER 95-001-02:on 950123,DG Turbocharger Failure Resulted in Noncompliance W/Ts Lco.Instituted Vibration Monitoring Program for EDG Turbochargers ML18038B8071997-01-15015 January 1997 LER 96-008-00:on 961217,loss of ECCS Division II Instrumentation Caused ECCS Equipment to Be Inoperable. Replaced Cleared Fuse & Shorted SCR ML18038B8041997-01-13013 January 1997 LER 96-007-00 on 961213,engineered Safety Feature Actuations Resulting from Inadequate Planning of step-text Work Order Occurred.Tripped Breaker Reset & LCO Condition Exited ML18038B7931996-12-0404 December 1996 LER 96-006-00:on 961106,loss of ECCS Div 1 Instrumentation Rendered ECCS Equipment Inoperable.Caused by Cleared Fuse in ECCS Div.Fuse Replaced & Addl Testing to Challenge Replacement Fuse performed.W/961204 Ltr ML18038B7921996-11-27027 November 1996 LER 96-008-00:on 961101,MS SR Valves Exceeded TS Required Setpoint Limit as Result of Disc/Seat Bonding.Caused by Corrosion Bonding of SRV Pilot Interface.Replaced All Thirteen Ms SR Valve Pilot cartridges.W/961127 Ltr ML18038B7911996-11-27027 November 1996 LER 96-007-00:on 961029,Unit 2 Scram on Turbine Control Valve Fast Closure Occurred Due to Loss of Excitation to Main Generator.Exciter Brushes Inspected & Replaced & Procedures Revised ML18038B7741996-10-15015 October 1996 LER 96-005-03:on 960915,reactor Scrammed as Required by TSs Due to Trip of Reactor Recirculation Motor Generator Set 3A. Caused by Bus Bar in Generator Armature Circuit Failing. Collector Rings Were replaced.W/961015 Ltr 1999-09-30
[Table view] Category:RO)
MONTHYEARML18039A9041999-10-15015 October 1999 LER 99-010-00:on 990917,automatic Reactor Scram on Turbine Stop Valve Closure Occurred.Caused by High Water Level in Main Steam Moisture Separator 2C2.Unit 2C2 Reservoir Level Transmitter & Relays Were Replaced & Tested Satisfactorily ML18039A8981999-10-14014 October 1999 LER 99-009-00:on 990915,manual Reactor Scram Was Noted Due to EHC Leak.Caused by Failure of Stainles Steel Tubing Connection.Removed Damaged Tubing & Connection Plug ML18039A8951999-10-0808 October 1999 LER 99-008-00:on 990905,HPCI Was Inoperable Due to Failed Flow Controller.Caused by Premature Failure of Capacitor 2C3.Replaced Controller & HPCI Sys Was Run IAW Sys Operating Instructions ML18039A8751999-09-30030 September 1999 LER 99-005-00:on 990901,SR for Standby Liquid Control Sampling Was Not Met.Caused by Deficient Procedure for Chemical Addition to Standby Liquid Control.Revised Procedure.With 990930 Ltr ML18039A8201999-07-26026 July 1999 LER 99-004-00:on 990625,facility Core Spray Divisions I & II Inoperable at Same Time Due to Personnel Error.Electrical Supply Breaker to Core Spray Division II Pump 3B Returned to Normal Racked in Position ML18039A8171999-07-20020 July 1999 LER 99-007-00:on 990623,discovered That SR for Monitoring of Primary Containment Oxygen Concentration Had Not Been Met. Caused by Failure of Operators to Adequately Communicate. Required Surveillances Were Performed.With 990720 Ltr ML18039A8161999-07-19019 July 1999 LER 99-006-00:on 990618,noted That Main Steam SRV Exceeded TS Setpoint Tolerance.Caused by Pilot Vlve disc-seat Bonding.Util Replaced All 13 SRV Pilot Cartridges with Cartridges Certified to Be Witin +/-1%.With 990719 Ltr ML18039A8121999-07-12012 July 1999 LER 99-005-00:on 990617,ESF Actuation & HPCI Declared Inoperable.Caused by Personnel Error.Reset HPCI & Returned Sys to Operable Status with 25 Minutes.With 990712 Ltr ML18039A8101999-06-28028 June 1999 LER 99-004-00:on 990530,safety Features Sys Actuations Occurred Due to RPS Trip.Caused by Failure of MG Set AC Drive Motor Starter Contractor Coil.Licensee Placed 2B RPS Bus on Alternate Feed & Half Scram Was Reset ML18039A8011999-06-14014 June 1999 LER 99-001-00:on 990515,automatic Reactor Scram Occurred Due to Tt.Caused by Failure of Mechanical Trip Cylinder to Latch When Hydraulically Reset.Operations Crew Stabilized Reactor Following Scram.With 990614 Ltr ML18039A8021999-06-14014 June 1999 LER 99-002-00:on 990501,SRs for Single CR Withdrawal During Cold SD Were Not Adequately Implemented.Caused by Procedural Inadequacy.Revised Applicable Plant Surveillances.With 990614 Ltr ML18039A8071999-06-14014 June 1999 LER 99-003-00:on 990515,automatic Reactor Scram Due to Turbine Trip Was Noted.Caused by Failure of Mechanical Trip Cylinder to Latch When Hydraulically Reset.Operations Crew Stabilized Reactor Following Scram ML18039A7791999-05-0606 May 1999 LER 99-003-00:on 990408,declared Plant HPCI Sys Inoperable Due to Loose Wire.Caused by Failure to Properly Tighten Screw at Some Time in Past.Loose Wire Was Tightened ML18039A7461999-04-0707 April 1999 LER 99-001-00:on 990308,determined That Two Trains of Standby Gas Treatment (SGT) Were Inoperable.Caused by Trip C SGT Blower Motor Breaker.Initiated Shutdown of Plant,Reset C SGT Blower Motor Breaker & Declared Train Operable ML18039A6951999-02-19019 February 1999 LER 99-002-00:on 990122,LCO Was Not Entered During Calibration Testing of 3D 480 Volt Rmov Board.Caused by Personnel Error.Tva Has Briefed Operations Personnel to Preclude Recurrence of Event.With 990219 Ltr ML18039A6871999-02-12012 February 1999 LER 99-001-00:on 990114,Unit 3 HPCI Was Noted Inoperable. Caused by Oil Leak on Stop Valve.Corrective Maint Was Performed to Repair Oil Leak.With 990212 Ltr ML18039A6671998-12-31031 December 1998 LER 98-004-00:on 981202,SR Intent Was Not Adequately Implemented.Caused by Procedural Inadequacy.Revised Procedures to Provide Proper SR Implementation.With 981231 Ltr ML18039A6471998-12-15015 December 1998 LER 98-007-00:on 981116,unplanned ESF Following Loss of 4kV Unit Board 3B Occurred.Caused by Temporary Energization of Lockout Relay on 4kV Unit Board 3B When Resistor on Relay Monitoring Lamp Circuit Shorted.Replaced Resistor ML18039A6371998-12-0707 December 1998 LER 98-006-00:on 981116,MSSR Valves Exceeded TS Setpoint Tolerance.Caused by Pilot Valve Disc/Seat Bonding. Installed SRV Pressure Switches During Unit 3,cycle 8 Outage.With 981207 Ltr ML18039A6071998-11-12012 November 1998 LER 98-005-00:on 981014,mode Changes Not Allowed by TS 3.0.4 Were Made During Reactor Startup.Caused by TS LCO 3.0.4 Not Being Properly Applied.Training Info Memo Re Proper Application for TS LCO 3.0.4 Was Prepared.With 981112 Ltr ML18039A6031998-11-0404 November 1998 LER 98-004-00:on 981007,primary Containment Allowable Leak Rate Was Exceeded.Caused by Failure of Check Valve to Fully Seat Following Shutdown of Rbbccw Sys for Llrt.Valve Was Retested During Next Refueling Outage.With 981104 Ltr ML18039A5971998-10-28028 October 1998 LER 98-003-00:on 981001,Unit 2 Received Full Automatic Scram from 100% Reactor Power.Caused by Failure of Normally Open Isolation Valve Which Blocked Flow of Stator Cooling Water Through Associated Heat Exchangers.Replaced Failed Valve ML18039A5171998-09-15015 September 1998 LER 98-002-00:on 980816,personnel Observed Both Channels of Rod Block Monitor Sys Bypassed for Cr.Caused by Failure of Gene to Properly Document & Specify Adjustments.Will Implement Necessary Procedure Controls ML18039A3311998-05-0404 May 1998 LER 98-003-00:on 980407,reactor Manually Scrammed to Prevent thermal-hydraulic Instability After Recirculation Pump Runback.Caused by Human Error.Strengthened Controls Associated W/Walkdowns in NEDP-11 ML18039A3141998-04-0909 April 1998 LER 98-002-00:on 980310,ESF Actuation Occurred Due to Failure of Alternate Feeder Breaker Position Switch.Will Continue Testing & Visual Insps on Addl Breaker Position Switches & Will Revise Applicable Maint Instructions ML18039A3101998-04-0707 April 1998 LER 98-001-00:on 980308,ESF Actuations Occurred When 2B RPS Bus Was Transferred to de-energized Source.Caused by Failure of Preparing Clearance to Exercise Proper Attention. 2B RPS Bus Restored to Transformer Source ML18039A3051998-04-0101 April 1998 LER 96-001-00:on 980121,determined That Temp Sensors for Certain HELB May Not Detect All Possible Break Locations. Caused by Differences in Computer Codes Rather than Actual Response.Computer Code Correctly Utilized ML18039A2041997-12-0303 December 1997 LER 97-008-00:on 971104,main Steam Safety/Relief Valves Exceeded TS Setpoint Limit.Caused by Pilot Valve Disc/Seat Bonding.Replaced All 13 Unit 2 Main Steam SRV Pilot Cartridges ML18038B9961997-11-25025 November 1997 LER 97-007-00:on 971028,Unit 2 Automatically Scrammed.Caused by Momentary Pressure Drop in electro-hydraulic Control Sys at Turbine Control Valves.Scram Contactor Replaced ML18038B9931997-11-18018 November 1997 LER 97-006-00:on 971019,declared Unit 2 Hpcis Inoperable. Caused by High Condensate Level in HPCI Turbine Inlet Steam Line Drain Pot.Work Request Initiated ML18038B9861997-11-10010 November 1997 LER 97-005-00:on 971012,ESF Components Were Actuated.Caused by Inadequate Procedure.Cs Pumps Were Secured & Injection Valves Were Closed & Refueling Floor Activities Were Stopped ML18038B9701997-10-0909 October 1997 LER 97-004-00:on 970909,TS Surveillances Were Not Performed During Refueling Outage Timeframe.Caused by Personnel Error. Incorporated Missed Snubber & Vacuum Breaker Surveillances Into Refueling Outage Schedule ML18038B9661997-10-0303 October 1997 LER 97-005-00:on 970824,LCO Was Not Entered When Valve Was Malfunctioning.Caused by Lack of Questioning Attitude by Operations Crew.Involved SROs Were Counseled & Problem Evaluation Rept Will Be Discussed ML18038B9321997-08-0707 August 1997 LER 97-003-00:on 970711,determined That HPCI Turbine Speed Lower than Indicated.Caused by Improper Evaluation of Valve Leak.Work Orders to Troubleshoot HPCI Initiated ML18038B9231997-07-25025 July 1997 LER 97-002-00:on 970626,discovered That Four Surveillance Instructions (Sis) Did Not Fully Test All Relay Logic Combinations.Caused by Personnel Error.Verified Relay Contacts Operable & Revised Applicable SIs.W/970725 Ltr ML18038B8811997-05-14014 May 1997 LER 97-004-00:on 970414,unplanned Manual Start of EDG During Scheduled Redundant Start Test Occurred.Caused by Personnel Error.Edg 3D Shutdown & Returned to pre-event Configuration. W/970514 Ltr ML18038B8801997-05-0808 May 1997 LER 97-002-00:on 970410,HPCI Declared Inoperable.Caused by Personnel Error.Operations Personnel Stopped Instrument Mechanics Testing & Returned HPCI to Standby Readiness. W/970508 Ltr ML18038B8701997-04-29029 April 1997 LER 96-004-02:on 960717,loss of ECCS Division I & Division II Instrumentation Renders ECCS Equipment Inoperable.Caused by Loss of Inverter Output.Failed Components Replaced in Atu Inverter Circuitry & Instrumentation Logic Restored ML18038B8521997-04-0909 April 1997 LER 97-003-00:on 970314,Unit 3 Main Steam SRVs Pilot Cartridges Failed Setpoint Tolerance Bench Tests.Caused by Corrosion Bonding of SRV Pilot Disc/Seat Interface Resulting in Drifting.Main Steam SRV Pilot replaced.W/970409 Ltr ML18038B8511997-04-0909 April 1997 LER 95-003-02:on 950301,Unit 2 Main Steam SRVs Failed Setpoint Acceptance Tests.Caused by Corrosion Bonding of SRV Pilot Disc/Seat Interface Resulting in Upward Setpoint Drift.Valves Currently Being Retested & Recertified ML18038B8481997-04-0909 April 1997 LER 96-004-01:on 960425,Unit 2 SRV Pilot Cartridges Failed Setpoint Acceptance Tests.Caused by SRV Pilot Disc/Seat Bonding Resulting in SRV Setpoints Deviating.Valves Currently Being Retested & Recertified ML18038B8451997-04-0909 April 1997 LER 96-008-01:on 961101,Unit 2 Main Steam SRV Pilot Cartridges Failed Setpoint Tolerence Bench Tests.Caused by SRV Pilot Disc/Seat Bonding Resulting in SRV Setpoints.Srv Pilot Cartridges replaced.W/970409 Ltr ML18038B8551997-04-0404 April 1997 LER 97-001-00:on 970305,loss of Offsite Power on Unit 3 During Refueling Outage Resulted from Shorted Component. Replaced Relays Involved in Event W/Less Sensitive Relays ML18038B8441997-03-26026 March 1997 LER 95-001-02:on 950123,DG Turbocharger Failure Resulted in Noncompliance W/Ts Lco.Instituted Vibration Monitoring Program for EDG Turbochargers ML18038B8071997-01-15015 January 1997 LER 96-008-00:on 961217,loss of ECCS Division II Instrumentation Caused ECCS Equipment to Be Inoperable. Replaced Cleared Fuse & Shorted SCR ML18038B8041997-01-13013 January 1997 LER 96-007-00 on 961213,engineered Safety Feature Actuations Resulting from Inadequate Planning of step-text Work Order Occurred.Tripped Breaker Reset & LCO Condition Exited ML18038B7931996-12-0404 December 1996 LER 96-006-00:on 961106,loss of ECCS Div 1 Instrumentation Rendered ECCS Equipment Inoperable.Caused by Cleared Fuse in ECCS Div.Fuse Replaced & Addl Testing to Challenge Replacement Fuse performed.W/961204 Ltr ML18038B7921996-11-27027 November 1996 LER 96-008-00:on 961101,MS SR Valves Exceeded TS Required Setpoint Limit as Result of Disc/Seat Bonding.Caused by Corrosion Bonding of SRV Pilot Interface.Replaced All Thirteen Ms SR Valve Pilot cartridges.W/961127 Ltr ML18038B7911996-11-27027 November 1996 LER 96-007-00:on 961029,Unit 2 Scram on Turbine Control Valve Fast Closure Occurred Due to Loss of Excitation to Main Generator.Exciter Brushes Inspected & Replaced & Procedures Revised ML18038B7741996-10-15015 October 1996 LER 96-005-03:on 960915,reactor Scrammed as Required by TSs Due to Trip of Reactor Recirculation Motor Generator Set 3A. Caused by Bus Bar in Generator Armature Circuit Failing. Collector Rings Were replaced.W/961015 Ltr 1999-09-30
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML18039A9041999-10-15015 October 1999 LER 99-010-00:on 990917,automatic Reactor Scram on Turbine Stop Valve Closure Occurred.Caused by High Water Level in Main Steam Moisture Separator 2C2.Unit 2C2 Reservoir Level Transmitter & Relays Were Replaced & Tested Satisfactorily ML18039A8981999-10-14014 October 1999 LER 99-009-00:on 990915,manual Reactor Scram Was Noted Due to EHC Leak.Caused by Failure of Stainles Steel Tubing Connection.Removed Damaged Tubing & Connection Plug ML18039A8951999-10-0808 October 1999 LER 99-008-00:on 990905,HPCI Was Inoperable Due to Failed Flow Controller.Caused by Premature Failure of Capacitor 2C3.Replaced Controller & HPCI Sys Was Run IAW Sys Operating Instructions ML18039A8751999-09-30030 September 1999 LER 99-005-00:on 990901,SR for Standby Liquid Control Sampling Was Not Met.Caused by Deficient Procedure for Chemical Addition to Standby Liquid Control.Revised Procedure.With 990930 Ltr ML20217F9671999-09-30030 September 1999 Monthly Operating Repts for Sept 1999 for Browns Ferry Nuclear Plant,Units 1,2 & 3.With ML20212E6341999-09-23023 September 1999 Suppl to SE Resolving Error in Original 990802 Se,Clarifying Fact That Licensee Has Not Committed to Retain Those Specific Compensatory Measures That Were Applied to one-time Extension ML20212D3831999-09-20020 September 1999 Safety Evaluation Supporting Proposed Rev to Withdrawal Schedule for First & Third Surveillance Capsules for BFN-3 RPV ML20212B8561999-08-31031 August 1999 Monthly Operating Repts for Aug 1999 for Browns Ferry Nuclear Plant.With ML18039A8821999-08-31031 August 1999 Increased MSIV Leakage Tech Spec Change Submittal - Seismic Evaluation Rept. ML18039A8391999-08-0606 August 1999 BFN Unit 2 Cycle 10 ASME Section XI NIS-1 & NIS-2 Data Repts. ML20210N1221999-08-0202 August 1999 Safety Evaluation Accepting Licensee Request for Relief from ASME B&PV Code,Section XI Requirements.Request 3-ISI-7, Pertains to Second 10-year Interval ISI for Plant,Unit 3 ML20210R0931999-07-31031 July 1999 Monthly Operating Repts for July 1999 for Browns Ferry Nuclear Plant,Units 1,2 & 3.With ML18039A8201999-07-26026 July 1999 LER 99-004-00:on 990625,facility Core Spray Divisions I & II Inoperable at Same Time Due to Personnel Error.Electrical Supply Breaker to Core Spray Division II Pump 3B Returned to Normal Racked in Position ML18039A8171999-07-20020 July 1999 LER 99-007-00:on 990623,discovered That SR for Monitoring of Primary Containment Oxygen Concentration Had Not Been Met. Caused by Failure of Operators to Adequately Communicate. Required Surveillances Were Performed.With 990720 Ltr ML18039A8161999-07-19019 July 1999 LER 99-006-00:on 990618,noted That Main Steam SRV Exceeded TS Setpoint Tolerance.Caused by Pilot Vlve disc-seat Bonding.Util Replaced All 13 SRV Pilot Cartridges with Cartridges Certified to Be Witin +/-1%.With 990719 Ltr ML20209J0771999-07-16016 July 1999 Safety Evaluation Concluding That Licensee Provided Adequate Information to Resolve ampacity-related Points of Concern Raised in GL 92-08 for BFN & That No Outstanding Issues Re GL 92-08 Ampacity Issues for Browns Ferry NPP Exist ML18039A8121999-07-12012 July 1999 LER 99-005-00:on 990617,ESF Actuation & HPCI Declared Inoperable.Caused by Personnel Error.Reset HPCI & Returned Sys to Operable Status with 25 Minutes.With 990712 Ltr ML20209H4381999-06-30030 June 1999 Monthly Operating Repts for June 1999 for Browns Ferry Nuclear Plant,Units 1,2 & 3.With ML18039A8101999-06-28028 June 1999 LER 99-004-00:on 990530,safety Features Sys Actuations Occurred Due to RPS Trip.Caused by Failure of MG Set AC Drive Motor Starter Contractor Coil.Licensee Placed 2B RPS Bus on Alternate Feed & Half Scram Was Reset ML20196F8811999-06-23023 June 1999 Safety Evaluation Accepting GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power Operated Gate Valves ML18039A8071999-06-14014 June 1999 LER 99-003-00:on 990515,automatic Reactor Scram Due to Turbine Trip Was Noted.Caused by Failure of Mechanical Trip Cylinder to Latch When Hydraulically Reset.Operations Crew Stabilized Reactor Following Scram ML18039A8021999-06-14014 June 1999 LER 99-002-00:on 990501,SRs for Single CR Withdrawal During Cold SD Were Not Adequately Implemented.Caused by Procedural Inadequacy.Revised Applicable Plant Surveillances.With 990614 Ltr ML18039A8011999-06-14014 June 1999 LER 99-001-00:on 990515,automatic Reactor Scram Occurred Due to Tt.Caused by Failure of Mechanical Trip Cylinder to Latch When Hydraulically Reset.Operations Crew Stabilized Reactor Following Scram.With 990614 Ltr ML20196B8051999-05-31031 May 1999 Monthly Operating Repts for May 1999 for Browns Ferry Nuclear Plant,Units 1,2 & 3.With ML18039A7791999-05-0606 May 1999 LER 99-003-00:on 990408,declared Plant HPCI Sys Inoperable Due to Loose Wire.Caused by Failure to Properly Tighten Screw at Some Time in Past.Loose Wire Was Tightened ML18039A7761999-04-30030 April 1999 Revised Surveillance Specimen Program Evaluation for TVA Browns Ferry Unit 3. ML20206R0731999-04-30030 April 1999 Monthly Operating Repts for Apr 1999 for Bfnp.With ML18039A7561999-04-23023 April 1999 Bfnp Risk-Informed Inservice Insp (RI-ISI) Program Submittal. ML18039A7671999-04-0808 April 1999 Rev 0 to TVA-COLR-BF2C11, Browns Ferry Nuclear Plant Unit 2 Cycle 11 Colr. ML18039A7461999-04-0707 April 1999 LER 99-001-00:on 990308,determined That Two Trains of Standby Gas Treatment (SGT) Were Inoperable.Caused by Trip C SGT Blower Motor Breaker.Initiated Shutdown of Plant,Reset C SGT Blower Motor Breaker & Declared Train Operable ML20205N8341999-04-0101 April 1999 Part 21 Rept Re Automatic Switch Co Nuclear Grade Series X206380 & X206832 Solenoid Valves Ordered Without Lubricants That Were Shipped with Std Lubrication to PECO & Tva.Affected Plants Were Notified ML20205F9341999-04-0101 April 1999 Safety Evaluation Authorizing Licensee 990108 Relief Request PV-38,from Requirements of ASME BPV Code Section XI IST Testing,Valve Program for Plant,Units 1,2 & 3 ML20205T5441999-03-31031 March 1999 Monthly Operating Repts for Mar 1999 for Bfnp.With ML20205S0601999-03-31031 March 1999 Rept on Status of Public Petitions Under 10CFR2.206 with Status Change from Previous Update,990331 ML20205S0661999-03-31031 March 1999 Rept on Status of Public Petitions Under 10CFR2.206 with No Status Change from Previous Update,990331, Atlas Corp ML18039A7361999-03-11011 March 1999 Rev 4 to TVA-COLR-BF2C10, Bfnp,Unit 2,Cycle 10 Colr. ML20204C7891999-02-28028 February 1999 Monthly Operating Repts for Feb 1999 for Browns Ferry Nuclear Plant,Units 1,2 & 3.With ML18039A6951999-02-19019 February 1999 LER 99-002-00:on 990122,LCO Was Not Entered During Calibration Testing of 3D 480 Volt Rmov Board.Caused by Personnel Error.Tva Has Briefed Operations Personnel to Preclude Recurrence of Event.With 990219 Ltr ML18039A6871999-02-12012 February 1999 LER 99-001-00:on 990114,Unit 3 HPCI Was Noted Inoperable. Caused by Oil Leak on Stop Valve.Corrective Maint Was Performed to Repair Oil Leak.With 990212 Ltr ML18039A6931999-02-0303 February 1999 Rev 3 to TVA-COLR-BF2C10, Bfnp Unit 2 Cycle 10 Colr. ML18039A6941999-02-0303 February 1999 Rev 1 to TVA-COLR-BF3C9, Bfnp Unit 3 Cycle 9 Colr. ML18039A6671998-12-31031 December 1998 LER 98-004-00:on 981202,SR Intent Was Not Adequately Implemented.Caused by Procedural Inadequacy.Revised Procedures to Provide Proper SR Implementation.With 981231 Ltr ML18039A6661998-12-31031 December 1998 Ro:On 981215,HRPCRM 2-RM-90-273C Was Declared Inoperable. Caused by Downscale Indication.Containment RM Will Be Utilized as Planned Alternate Method of Monitoring Until Hrpcrm 2-RM-90-273C Can Be Returned to Operable Status ML20199K8951998-12-31031 December 1998 Monthly Operating Repts for Dec 1998 for Browns Ferry Nuclear Plant.With ML20199F2721998-12-31031 December 1998 ISI Summary Rept (NIS-1), for BFN Unit 3,Cycle 8 Operation ML18039A6471998-12-15015 December 1998 LER 98-007-00:on 981116,unplanned ESF Following Loss of 4kV Unit Board 3B Occurred.Caused by Temporary Energization of Lockout Relay on 4kV Unit Board 3B When Resistor on Relay Monitoring Lamp Circuit Shorted.Replaced Resistor ML18039A6371998-12-0707 December 1998 LER 98-006-00:on 981116,MSSR Valves Exceeded TS Setpoint Tolerance.Caused by Pilot Valve Disc/Seat Bonding. Installed SRV Pressure Switches During Unit 3,cycle 8 Outage.With 981207 Ltr ML20199F2791998-12-0303 December 1998 Bfnp Unit 3 Cycle 8 ASME Section XI NIS-2 Data Rept ML20198D9621998-11-30030 November 1998 Monthly Operating Repts for Nov 1998 for Bfn,Units 1,2 & 3. with ML18039A6071998-11-12012 November 1998 LER 98-005-00:on 981014,mode Changes Not Allowed by TS 3.0.4 Were Made During Reactor Startup.Caused by TS LCO 3.0.4 Not Being Properly Applied.Training Info Memo Re Proper Application for TS LCO 3.0.4 Was Prepared.With 981112 Ltr 1999-09-30
[Table view] |
Text
~ CATEGORY 1 ~
REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NBR:9812160099 DOC.DATE: 98/12/07 NOTARIZED: NO DOCKET ¹ FACIL:50-296 Browns Ferry Nuclear Power Station, Unit 3, Tennessee 05000296 AUTH.NAME . , AUTHOR AFFILXATION ROGERS,A.T. Tennessee Valley Authority SINGER,K.W. Tennessee Valley Authority RECIP . NAME RECIPIENT AFFILIATION
SUBJECT:
LER 98-006-00:on 981116',MSSR valves exceeded TS setpoint tolerance. Caused by pilot valve disc/seat bonding. During cycle 8 outage SRV pressure switches were installed. With 981207 ltr.
DXSTRIBUT1ON CODE: XE22T COPIES RECEIVED:LTR ENCL 1 SIZE:
TITLE: 50.73/50.9 'Licensee Event Report (LER), Incident Rpt," etc.
NOTES:'RECIPIENT COPIES RECIPIENT , COPIES ZD CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-3-'PD 1 . 1 DEAGAZXO,A 1 1 INTERNAL: ACRS '1 1 .AEOD SPD RAB 2 2 AEOD/SPD/RRAB 1 1 ILE 1 1 NRR/DE/ECGB 1 1 NRR D E B 1 1 NRR/DE/EMEB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOHB 1 1, NRR/DRCH/HQMB 1 1 ERR/DRPM/PECB 1 1 NRR/DSSA/SPLB 1 1 RES/DET/EZB 1 1 RGN2 FILE Ol 1 1 D
EXTERNAL: L ST LOBBY WARD 1 1 LITCO BRYCE, J' 1 1 0' NOAC POORE,W. 1, 1 NOAC QUEENER, DS 1 1 NRC PDR 1 1 NUDOCS FULL TXT 1 1 NOTE TO 'ALL "RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE. TO HAVE YOUR NAME OR ORGANIZATION REMOVED FROM DISTRIBUTION LISTS OR REDUCE THE NUMBER OF. COPIES RECEIVED BY YOU"OR YOUR'ORGANIZATION, CONTACT THE DOCUMENT CONTROL DESK (DCD) ON EXTENSION 415-2083 FULL TEXT CONVERSION REQUXRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 23 ENCL '3
0 f Tennessee Valley Authortty, Post Offce Box 2000, Decatur, Alabama 35609-2000 Karl W. Singer Vice President, Browns Ferry Nuclear Rant December 7, l998 U.S. Nuclear Regulatory Commission 10 CFR 50.73 ATTN: Document Control Desk Washingtonr D C 20555
Dear Sir:
BROGANS FERRY NUCLEAR PLANT (BFN) UNIT 3 DOCKET NO. 50-296 FACILITY OPERATING LICENSE DPR-68 LICENSEE EVENT REPORT (LER) 50-296/1998006 The enclosed report provides details concerning Unit 3 main steam safety/relief valves that exceeded their technical specifications setpoint tolerances during surveillance testing. This report is submitted in accordance with 10 CFR 50.73 (a)(2)(i)(B) as a condition prohibited by the plant's technical specifications.
Sincerely, alW. n cc: See page 2 98i2160099 98 0S0O 0296 PDR AOOCK
i U.. S. Nuclear Regulatory Commission Page 2 December 7, 1998 Enclosure cc (Enclosure):
Mr. H. 0. Christensen,, Branch Chief U.S. Nuclear Regulatory Commission Region II Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30303-3415 NRC Resident Inspector Browns Ferry Nuclear Plant 10833 Shaw Road Athens, Alabama 35611 Mr. L. Raghavan, Project Manager U. S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike
.Rockville, Maryland 20852-2739
I il Cl k
NRC FORM 366 U.S. NUCL REGULATORY COMMISSION APPROVED 8 NO. 3150-0104 EKPmm 08/30/2001 I6.1998) Estimated burden per response to comply with this mandatory information collection request: 50 hrs. Reported lessons learned are incorporated into LICENSEE EVENT REPORT (LER) the licensing process and fed back to industry. Forward comments regarding burden estimate to the Records Management Branch (TW F33). U.S.
Nuclear Regulatory Commission, Washington, DC 205554001, and to the (See reverse for required number of pape)wc/k Reductkx) Project (3)500)04), Office of Management and Budget, Washington. DC 20503. If an Information collection does not digits/characters for each block) dIsplay a currently valid 0MB control number, the NRC may not conduct or sponsor. and a person Ls not required to respond to, the Information collection.
DOCKET NUMBER 131 PAOE (3)
FACIUTY NAME 11)
Browns Ferry Nuclear Plant Unit 3 05000296 1 of6 TITLE l4)
Main Steam Safety/Relief Valves Exceeded The Technical Specifications Setpoint Tolerance Due To Pilot Valve Disc/Seat Bonding EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED IS)
REVISION MONTH DAY FACIUTY NAME DOCKETNVMBER MONTH DAY YEAR YEAR SEQUENTIAL NUMBER NUMBER NA DOCKET NUMBER 16 98 1998 006 0 12 07 98 NA OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR II: (Check one or more MODE (9) 20. 2201 (b) 20. 2203(a) (2) (v) X 50.73(a)(2)(i)(B) 50.73(a)(2)(viii)
POWER 20,2203(a) (1) 20.2203(a)(3) (i) 50.73(a)(2)(ii) 50.73(a)(2)(x)
LEVEL (10) 20.2203(a) (2)(i) 20.2203(a) (3)(ii) 50.73(a) (2) (iii) 73.71 100
'0.2203(a)(2)(ii) 20.2203(a) (4) 50.73(a)(2)(iv) OTHER 20.2203(a) (2) (iii) 50.36(c)(1) 50 73(a)(2)(v) Specify In Abstract below or in NRC Form 366A
- 20. 2203(a) (2) (iv) 50.36(c) (2) 50.73(a)(2)(vii)
LICENSEE CONTACT FOR THIS LER (12)
NAME TELEPHONE NUMBER (Include Area Code)
Anthony T. Rogers, Senior Licensing Project Manager (256) 729-2977 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT- (13)
COMPONENT MANUFACTURER REPORTABLE TO CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE
.CAUSE SYSTEM NPRDS TO NPRDS SB RV T020 SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED MONTH OAY YEAR X No SUBMISSION YES DATE (15)
(It Yes, complete EXPECTED SUBMISSION DATE).
ABSTRACT (Limit to 1400 spaces, i'.e., approximately 15 single-spaced typewritten lines) (16)
On November 16, 1998, Wyle Laboratories notified TVA that 5 of the 13 Unit 3 main steam. safety/relief valves (SRV) pilot cartridges removed during the Unit 3 Cycle 8 refueling outage bench tested outside the Technical Specifications (TS) setpoint tolerance of+/- 3 percent. The Unit 3 SRV pilot cartridges were installed'dunng the previous refueling outage and were in service from March 1997 to September 1998.
The cause was attributed to SRV pilot disc/seat corrosion bonding at-the two-stage SRV pilot disc/seat interface which resulted in drifting of the SRV setpoints. Setpoint drift is a genenc concern experienced by many utilities using Target Rock Two-Stage SRVs (Model No. 7567F) in boiling water reactors and is being investigated by the Boiling Water Reactor Owners Group (BWROG) SRV Drift Fix Development Committee and the valve manufacturer. TVA will continue to participate in the BWROG evaluation of the long-term solution for the SRV setpoint drift problem. Also, during the Unit 3, Cycle 8 outage, SRV pressure switches were installed which actuate the SRVs during pressurization transients. This system minimizes the effects of SRV setpoint drift.
This condition is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by the plant's TS.
NRC FORM 366B (6-1998)
C NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION IS-1998)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME 1 DOCKET LER NUMBER 6 PAGE 3 YEAR SEQUENTIAL REVISION NUMBER 2of 6 Browns Ferry Nuclear Plant - Unit 3 05000296 1998 - 006 00 TEXT iifmore spece is required, use edditionel copies of NRC Form 366Ai i17l I. PLANT CONDITION(S)
At the time of the discovery of this condition, Unit 3 was at 100 percent power following a refueling outage, Unit 2 was operating at 100 percent power, and Unit 1 was shutdown and defueled.
II. DESCRIPTION OF EVENT A. Event:
On November 16, 1998, Wyle Laboratories notified TVA that 5 of the 13 main steam [SB] safety/relief valves (SRV) [RV] pilot cartridges tested at their laboratory in Huntsville, Alabama failed the setpoint tolerance bench tests. The pilot cartridges were previously removed from the Unit 3 SRVs (Target Rock Two-Stage SRV Model No. 7567F) during the Unit'3 Cycle 8 refueling outage in September 1998 and shipped to Wyle Laboratories for testing. The pilot cartridges had been installed during the previous Unit 3 refueling outage.
Altogether, Wyle Laboratories tested 5 SRV platinum-stellite and 8 stellite pilot disc cartridges. 1 platinum-stellite and 4 stellite cartridges failed the as-found setpoint tolerance bench tests. The setpoints were found. outside the Technical Specifications (TS) tolerance of+/- 3 percent which is approximately 33 pounds per square inch (psi). See Table 1 for specific SRV pilot cartridge test results.
B. Ino erable Structures Com onents or S stems that Contributed to the Event:
None.
C. Dates and A roximate Times of Ma or Occurrences:
March 1997 Pilot cartridges installed on Unit 3 SRVs during Cycle 7 outage.
September 20, 1998 Unit 3 entered Cycle 8 refueling outage.
September 28, 1998 Pilot cartridges removed from SRVs and shipped to Wyle Laboratories.
November 16, 1998 Wyle Laboratories notified TVA of the SRV pilot.
cartridges test results.
D. OtherS stems orSeconda FunctionsAffected None.
.E. Method of Discove This condition was identified during valve bench testing at Wyle Laboratories in Huntsville, Alabama.
NRC FORM 366 I6-1998)
il NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (6-1998) ilCENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME 1 DOCKET LER NUMBER 6 PAGE 3 YEAR SEOUENTIAL REViSioN NUMBER 3of 6 Browns Ferry Nuclear Plant - Unit 3 05000296 1998 - 006 - 00 TEXT fitmoro spece is required, use edditionel copies of NRC Form'366A/ l17)
F. 0 erator Actions None.
G. Safe S stem Res onses None.
III. CAUSE OF THE EVENT A. Immediate Cause None.
B. Root Cause 5 of the 13 SRV pilot cartridges opened above the TS setpoint tolerance of+ 3 percent (33 psi). The cause was attributed to SRV pilot disc/seat corrosion bonding at the two-stage SRV pilot disc/seat interface. The corrosion bonding results in an increase in the valve opening pressure due to the need for additional opening force.
SRV setpoint drift is a generic concern experienced by utilities using Target Rock Two-Stage SRVs in boiling water reactors and is being investigated by the BWROG SRV Drift Fix Development Committee and the valve manufacturer. A final remedy for the problem has yet to be identified. TVA will continue to participate in the BWROG evaluation'of the long-term solution for the SRV setpoint drift problem.
TVA had previously implemented the BWROG recommendation of replacing some of the SRV pilot cartridges with cartridges that have 0.3 percent platinum alloyed stellite pilot disc. Use of platinum-stellite discs has not corrected the SRV setpoint drift problem (see LERs 260/96004, 260/96008 and 260/97008), but the platinum-stellite discs generally demonstrate better performance than non-platinum discs. This cycle only one of five platinum-stellite valves was outside the TS limit as shown in Table 1.
IV. ANALYSIS OF THE EVENT There are 13 SRVs on the main steam piping. The valves are designed to perform the mechanical overpressure safety/relief function for the primary reactor system boundary by opening at a reactor pressure of 1105, 1115, and 1125 psig as shown in Table 1. The safety/relief function of the SRVs is to limit primary reactor system pressure in the event of a pressurization transient resulting from a turbine trip or a main steam isolation valve closure. The failure of the 5 SRVs (from approximately+3.34 to +6.55 percent above their setpoint pressure) would not have resulted in exceeding the TS safety limit during any abnormal operational transient.
NRc FoRM 366 l6-1998)
0 t I
NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION IS-1998)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME 1 DOCKET LER NUMBER 6 PAGE 3 YEAR SEQUENTIAL REVISION NUMBER 4of 6 Browns Ferry Nuclear Plant - Unit 3 05000296 1 996 006 - 00
'EXT'lfmore space is required, use addidonal copies of NRC Form 366A/ (17)
V. ASSESSMENT OF SAFETY CONSEQUENCES The reload licensing analyses for the Unit 3 Cycle 8 pressurization transients were performed using an assumed+ 3 percent drift of the SRVs from the TS values and assumed one inoperable SRV. The. as-found average SRV setpoint drift was+ 2.63 percent. Assuming the most conservative valve (-1.18 percent drift) inoperable results in an average SRV setpoint drift of+ 2.95 percent. Therefore, Unit 3 was within the reload specific analysis for this cycle.
TVA has previously performed a number of sensitivity evaluations (reference LERs 260/87005 and 296/97003) which show that SRV setpoint deviations of several percent in the high direction can be assumed in, the core transient analyses and still provide margin to reactor vessel pressurization limits. For example, the (current) Unit 2 Cycle 10 and Unit 3 Cycle 9 cycle specific transient reports assume a+ 6 percent SRV drift with acceptable results. Based on the as-found data, the previous sensitivity evaluations and the existing cycle specific analysis, the SRV drift would not have resulted in exceeding any safety limit.
VI CORRECTIVE ACTIONS
~
A. -Immediate Corrective Actions Piior to the recent Unit 3 restart, TVA replaced all 13 SRV pilot cartridges with cartridges certified to be within +/- 1 percent.
B. Corrective Actions to Prevent Recurrence SRV setpoint drift is a generic concern experienced by utilities using Target Rock Two-Stage SRVs in boiling water reactors and is being investigated by the BWROG SRV. Drift Fix Development Committee and the valve manufacturer. TVA will continue to participate in the BWROG evaluation of the long-term solution for the SRV setpoint drift problem.'uring the Unit 3, Cycle 8 refueling outage, a modification was implemented that installed pressure switches to actuate the SRVs. The pressure switches ensure the initiation of any SRV should it fail to open at its setpoint; thus, minimizing the effects of SRV setpoint drift.
VII. ADDITIONALINFORMATION A. Failed Com onents Target Rock, Two-Stage SRVs Model No. 7567F.
B. Previous'LERs on Similar Events There have been several previous LERs written concerning main steam SRV setpoint drift due to pilot valve disc/seat corrosion bonding (LERs'260/87005, 259/88053, 260/93003, 260/95003, 260/96004, 260/96008, 296/97003 and 260/97008). Previous corrective actions included'use of platinum-stellite pilot discs with some performance improvement. In addition, Unit 2 and Unit 3 have pressure switch modifications which provide an interim solution until the BWROG develops a ion -term resolution.
NRC FORM 366 (6-1998)
(r NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (6-1998)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME 1 DOCKET LER NUMBER 6 PAGE 3 YEAR SEQUENTIAL REVISION NUMBER sof 6 Browns Ferry Nucieh Plant - Unit 3 05000296 1998 - 006 00 TEXT (If more spaceis required, use additional copies of NRC Form 366Ai )17)
C. Additional'Information None.
VIII COMMITMENTS
~
None.
'TVA does not consider this corrective action a regulatory commitment. The completion of this item will be tracked in TVA's Corrective Action Program.
NRC FORM 366 l6-1998)
0 P
f
NRC FORM 366A U.S.. NUCLEAR REGULATORY COMMISSION
(&1998)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME 1 DOCKET LER NUMBER 6 PAGE 3 YEAR SEQUENTIAL REVISION NUMBER 6or 6 Browns Ferry Nuclear Plant - Unit 3 05000296 1998 - 006 00 TEXT (If more space is required, use additional copies of NRC Form 366A/ (17l Table 1 SRV AS-FOUND TEST RESULTS Five (5) of the following thirteen (13) Unit 3 main steam SRVs failed to meet the required TS setpoint tolerance (+/- 3 percent). The information for the failed SRV pilot cartridges is shown in bold type.
Nameplate As-Found Valve Setpoint Actuation Pressure Percent Cartridge Pilot Disc Pressure Pressure Difference Difference Serial No. Com osition PSIG PSIG PSIG 1084 stellite 1105 1092 -13 -1.18 1072 stellite 1105 1126 21 1.90 1020 stellite 1105 1143 38 3.34 1031 stellite 1105 1153 48 4.34 1028 platinum 1115 1155 40 3.59 1017 stellite 1115 . 1188 73 6.55 1076 platinum 1115 1128 13 1.17 1232 stellite 1115 1167 52 4.66 1014 platinum 1125 '1156 31 2.75 1015 platinum 1125 1153 28 2.49 1032 platinum 1125 1157 32 2.84 1016 stellite 1125 1114 -11 -0.98 1029 stellite 1125 1156 31 2.75 NRC FORM 366 l6-1998)
!I i)j lls t,',
if'