LER 93-011-00:on 930525,facility Started W/Invalid LLRT Having Been Performed on Drywell Head Seals.Initial Investigation Determined That RTV Applied W/O Approved Procedure.Incident Investigation Being ConductedML18038A992 |
Person / Time |
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Site: |
Browns Ferry ![Tennessee Valley Authority icon.png](/w/images/c/ce/Tennessee_Valley_Authority_icon.png) |
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Issue date: |
11/01/1994 |
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From: |
Jay Wallace TENNESSEE VALLEY AUTHORITY |
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To: |
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Shared Package |
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ML18038A990 |
List: |
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References |
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LER-93-011-01, LER-93-11-1, NUDOCS 9411070287 |
Download: ML18038A992 (16) |
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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
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NRC FORM 366 U.S NUCLEAR REGULATORY CQBIISSION APPROVED BY (NQI NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIHATED BURDEN PER 'RESPONSE TO COMPLY ,WITH THIS INFORHATIOH COLLECTION REQUEST: 50.0 HRS.
LZCENSEE EVENT REPORT (LER) FORlJARD COHMEHTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS HANAGEHENT BRANCH (MNBB 7714), U.S. NUCLEAR REGULATORY COHMISSION ~
(See reverse for required number of digits/characters for each block) WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3140-0104) ~ OFFICE OF MANAGEMENT AND BUDGET WASHINGTON DC 20503.
FACILITY NAME (1) DOCKET NWSER (2) PAGE (3)
Browns Ferr Nuclear Plant BFN Unit 2 05000260 1 OF 8 TITLE (4) An invalid local leak rate test on the dryweli head seals resulted in a condition prohibited by Technical Speci fications EVENT DATE 5 LER NWSER 6 REPORT DATE 7 OTHER FACILITIES INVOLVED 8 SEQUENTIAL REVISION FACILITY NAHE NA DOCKET NUHBER HOHTH DAY YEAR YEAR HONTH DAY YEAR NUMBER NUMBER FACILITY NAHE NA DOCKET NUMBER 05 25 93 93 011 00 1'1 01 OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR = Check one or mor e 11 INXJE'9) N 20.402(b) 20.405(c) 50.73(a)(2)(iv) 73.71(b) 20.405(a)(1)(i) 50.36(c) (1) 50.73(a)(2)(v) 73.71(c) 000 LEVEL (10) 20.405 (a) (1) (i i ) 50.36(c)(2) 50.73(a)(2)(vii) OTHER 20.405(a)(1)(iii) 50.73(a)(2)(i)(B) 50.73(a)(2)(viii)(A) (Specify in 20.405(a)(1)(iv) 50.73(a)(2)(ii) 50.73(a)(2)(viii)(B) Abstract below and in Text, 20.405(a)(1)(v) 50.73(a)(2)(iii) 50.73(a)(2)(x) NRC Form 366A LICENSEE CONTACT FOR THIS LER 12 NAHE TELEPHONE NUHBER (Include Area Code)
James E. Wallace, Compliance Licensing Engineer (205)729-7874 C(NPLETE ONE LINE FOR EACH C(NP(NJENT FAILURE DESCRIBED IN THIS REPORT 13 REPORTABLE REPORTABLE CAUSE SYSTEH COHPONENT HANUFACTURER CAUSE SYSTEM COMPONENT HANUFACTURER TO NPRDS TO NPRDS YES (If yes, cceylete SUPPLEMENTAL REPORT EXPECTED EXPECTED SUBHISSION DATE).
14 NO EXPECTED SUBMISSION DATE (15)
MONTH 01 '5 DAY YEAR 95 ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)
On October 2, 1994, during the Unit 2 Cycle 7 refueling outage, TVA was removing the Unit 2 drywell head when it was noticed that a sealant material (i.e.i RTV)i used to adhere the 0-ring seals in their grooves on the bottom flange, displaced from the grooves.
This condition occurred when the drywell head was reset on the lower flange during the Unit 2 Cycle 6 refueling outage. This condition existed when Unit 2 was restarted on May 25, 1993. It was determined that the excessive amount of RTV in the 0-ring grooves caused the LLRT performed during the last outage to be invalid.. This event is reportable in accordance with 10 CFR 50.73 (a).(2)(i.)(B) as a condition prohibited by BFN Technical Specifications. An initial investigation of this event determined that the RTV was appli.ed without an approved procedure, without proper authorization, and was not incorporated into the design prior to installation. Before reinstalling the drywell head, documentation will be provided as to limiting the amount of RTV allowed for the drywell head installation to ensure that it does not interfere with the LLRT. To further determine the root cause of the event and corrective actions to preclude recurrence, TVA is currently conducting an inci.dent i.nvestigation on this event after which a supplemental report will be submitted. The event date of'his report 'is May 25, 1993, when Unit 2 was restarted wi.th an invalid LLRT having been performed.
9411070287 '741101 PDR ADOCK 05000260 S PDR NRC FORM 366 (5 92)
0 0 NRC FORN 366A U.S NUCLEAR REGULATORY CQHIISS ION APPROVED SY MB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIHATED BURDEN PER RESPONSE TO COHPLY NITH THIS INFORHATIOH COLLECTIOH REQUEST: 50.0 HRS ~ FORllARD COHHENTS REGARDING BURDEN EST IHATE TO THE IHFORHATIOH AND RECORDS NANAGEHENT BRANCH (HNBB 7714), U.S. NUCLEAR REGULATORY COHNI SSI ON/
LICENSEE EVENT REPORT llASHIHGTOH~ DC 20555-0001, AND TO THE PAPERlQRK REDUCTION TEXT CONTINUATZON PROJECT (3150-0104), OFFICE OF IIANAGEHENT AND BUDGET, IIASHINGTOH DC 20503 FACILITY NAKE (1) DOCKET NINER (2) LER NWSER (6) PAGE (3)
YEAR SEQUENTIAL REVISION NUHBER NUHBER Browns Ferry Unit 2 05000260 93 011 00 2 of 8 TEXT If more s ce is r fred use additional co les of NRC Form 366A (17)
I ~ PLANT CONDITIONS At the time this event was discovered, Unit 2 was shutdown for a scheduled refueling outage. Units 1 and 3 were shutdown and defueled.
DESCRIPTION OF EVENT Ao Event On October 2, 1994, TVA was removing the BFN Unit 2 drywell head during a scheduled refueling outage. While removing the drywell head, personnel observed an excessive amount of sealing material (i.e., RTV-102) on the lower flange. The sealant had been used to facilitate installation of the drywell head 0-rings during the cycle 6 refueling outage. Additionally, approximately three inches of the inner 0-ring protruded from its groove (the drywell head flange 0-ring configuration is shown on page 7).
Based on the observations of the 0-rings [SEAL) when the drywell head [NH] was removed this outage, it was concluded that an invalid LLRT had been performed before the restart of Unit 2 on May 25, 1993. Specifically, the RTV was in the area between the O-rings, and the inner 0-ring seal was broken. Thus, the excessive amount of RTV obstructed the LLRT test volume.
Further details of this event are provided below.
On May 13, 1993, during the Unit 2 Cycle 6 refueling outage, the drywell head seal failed its initial as-left LLRT. RTV-102 was placed in the 0-ring grooves to augment the sealing characteristics of the 0-rings. The drywell head was subsequently reset, the bolts were retorqued, and the LLRT was reperformed on May 15, 1993. The followup LLRT measured 0.0036 SCFH of seal leakage which was within the acceptance criteria for this test.
The use of RTV-102 was not documented on applicable drawings; therefore, the use of this material should have required a design change to implement the addition of the RTV to the 0-rings. On May 16@ 1993'fter the drywell head was instal)ed and leak rate tested, a Design Change Notice (DCN) was processed to justify the use of RTV-102 to augment the sealing characteristics of the 0-rings. However, the engineering evaluation for the DCN failed to identify that excessive RTV would be forced out of the 0-ring groove upon compression of the 0-rings by the head flange. This amount would have been sufficient to obstruct the LLRT test volume.
NRC FQDI 366A U.S. NUCLEAR REGULATORY COB(I SSION APPROVED BY (NB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORIIARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEHENT BRANCH (MNBB 7714) ~ U.S. NUCLEAR REGULATORY COMMISSION, LICENSEE EVENT REPORT IIASHINGTON, DC 20555-0001, AND TO THE PAPERNORK REDUCTION TEXT CONTINUATION PROJECT (3150-0104) ~ OFFICE OF MANAGEHENT AND BUDGET ~
MASHINGTON DC 20503 FACILITY-NAME (1) DocKET ROBER (2) LER NUMBER (6) PAGE (3)
YEAR SEQUENTIAL REVISION NUMBER NUMBER Browns Ferry Unit 2 05000260 93 011 00 3 of 8 TEXT If more s ce is r ired use additional co ies of NRC Form 366A (17)
BFN Technical Specification 4.7.A requires that a LLRT of primary containment penetrations be performed once per operating cycle. The LLRT performed on the drywell head during the last refueling outage was determined to be invalid. Thus, this event is reportable pursuant to 10 CFR 50.73 (a)(2)(i)(B) due to a condition prohibited, by the BFN Technical Specifications. The event date of this report is May 25, 1993 when Unit 2 was restarted with an invalid LLRT. The discovery date of this event was October 2, 1994, which initiated the 30-day timeclock for reportability purposes.
As described further in Section IV of this report, TVA has not observed any abnormal leakage from the drywell 0-rings during the past operating cycle. An Incident Investigation (II) of this event is in progress.
B. Ino erable Structures Com onents or S stems that Contributed to the EventI None Co Dates and A roximate Times of Ma'or Occurrences:
May 13, 1993 The drywell head LLRT failed three times.
May 14, 1993 The drywell head was lifted, the grooves were cleaned, RTV-102 was placed in the 0-ring grooves, the drywell head was reset, and the bolts were retorqued.
May 15, 1993 The drywell head, LLRT was performed.
May 25, 1993 Unit 2 was restarted.
October 2, 1994 This condition was detected when the drywell'ead was lifted at the start of the next refueling outage.
D~ Other S stems or Seconda Functions Affected:
None.
0 I' NRC FORH 366A U.S NUCLEAR REGULATORY CWI SSION APPROVED BY QGI NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTINATED BURDEN PER RESPONSE TO COHPLY WITH THIS INFORHATION COLLECTION REQUEST: 50.0 NRS. FORWARD COHHENTS REGARD IHG BURDEN ESTINATE TO THE INFORHATION AND RECORDS HANAGENENT LICENSEE EVENT REPORT BRANCH (HNBB 7714) ~ U.S. NUCLEAR REGULATORY COHHISSION, TEXT CONTINUATION WASHINGTON, DC 20555-0001 'ND TO THE PAPERWORK REDUCTION PROJECT (3'l50-0104), OFFICE OF HANAGEHENT AND BUDGET, WASHINGTON DC 20503 FACILITY MANE (1) DOCKET NNSER (2) LER NOSER (6) , PAGE (3)
YEAR SEQUENTIAL REVISION NUHBER NUHBER Browns Ferry Unit 2 05000260 93 011 00 4 of 8 TEXT If more s ce is r uired use edditionsl co ies of NRC Form 366A (17)
ED Method of Discove This condition was discovered when the drywell head was being lifted off its lower flange during a scheduled outage after operating cycle 7,.
F. 0 erator Actionst None
'G. Safet S stem Res onses:
None ZZZ ~ CAUSE OF THE EVENT A. Immediate Causes The RTV was applied without an approved procedure, without proper authorization, and was not incorporated into the design prior to installation:" 'A 'de'Sign change notice was issued without correctly specifying the limit for the amount of RTV applied.
Bo Root Cause:
The root cause(s) of this event has not yet been determined.
TVA is currently conducting an Incident Investigation (II) of this event. The results of the II will be provided in a supplemental report.
ZVo ANALYSIS OF THE EVENT The top portion of the drywell is removable during refueling operations. The drywell head is connected to the remainder of the drywell via a flange connection held together by 208 bolts. This flange connection is sealed via a double captured seal ring arrangement. The dual 0-ring configuration and the intermediate leak rate testing tap permits leak rate testing of the drywell head flange seal.
As stated previously, an excessive amount of RTV was observed on the lower flange of the drywell head. The RTV was found to be uniformly distributed around the lower flange surface from near the inner radius of the flange across the 0-rings outward past the 0-ring grooves.
Examination of the RTV on the lower flange of the drywell head
NRC FORM 366A U S.,NUCLEAR REGULATORY C(MIIISSION APPROVED SY (MRI NO 3150-0104 (5-92) EXPIRES 5/31/95 ESTIHATED BURDEN PER-RESPONSE TO COMPLY MITN THIS INFORHATION COLLECTION REQUEST: 50 0 NRS. FORMARD COHHENTS REGARDING BURDEN EST IHATE TO THE INFORHATION AND RECORDS HAMAGEHENT BRANCH (HMBB 7714), U.S. NUCLEAR REGULATORY COHHISSION, LICENSEE EVENT REPORT llASMINGTOM, DC 20555-0001, AND TO THE PAPERllORK REDUCTION TEXT CONTINUATION PROJECT (3150-0104), OFFICE OF HANAGEHENT AND BUDGET, MASNINGTOM DC 20503 FACILITY NAME (1) DOCKET NQIBER (2) LER NIIQER (6) PAGE (3)
YEAR SEQUENTIAL REVISION NUMBER NUHBER Browns Ferry Unit 2 05000260 93 011 00 5 of 8 TEXT If more s ce is r ired use additional co ies of MRC Form 366A (17) indicated that it was adhering
'LLRT volume between the inner and tightly outer to the flange surface. The 0-rings was completely filled.
Approximately three inches of the inner 0-ring flange groove was empty because the 0-ring had been dislodged and was crushed between the flange surfaces, with a small portion extending from between the flange surfaces into the drywell interior.
Examination of the outer 0-ring indicated that associated groove and compressed along the entire circumference of the it was seated in its drywell head flange. Only one 0-ring is required to provide the seal between the upper and lower flange surfaces for the drywell head.
Therefore, the drywell head was effectively sealed.
Additionally, a calculation was performed to,determine the pressure in the drywell that would 'be required to overcome the bolt preload and lift the head. This calculation showed a pressure in excess of twice the design basis accident drywell pressure.
No abnormal nitrogen makeup [LK) requirements for drywell inerting were observed during operating cycle 7 (See chart 1 on page 8). The average amount of nitrogen consumed for the first 81 days was less than the amount that was used during operating cycle 6 when the drywell head was sealed without RTV [see chart 2 on page 8). However, the average amount of nitrogen consumed did increase over the remainder of the operating cycle 7. This increase was due to a drywell air compressor problem. If the drywell air compressor problem had not occurred, TVA believes that the nitrogen consumption would have continued to follow the trend of the first 81 days (i.e., less than cycle 6 nitrogen consumption). During the last two operating cycles, the amount of nitrogen consumed was significantly below the Technical Specifications limit.
Based on the examination of the joint flange, and the amount of nitrogen used to maintain the inerting of the drywell during the operating cycle, TVA has determined that an effective seal was in place.
Vo CORRECTIVE ACTIONS A. Immediate Corrective Actions:
Before reinstalling the drywell head during the Unit 2 Cycle 7 refueling outage, documentation will be provided as to limiting the amount of RTV allowed for the drywell head installation to ensure that it does not interfere with the LLRT. A Problem Evaluation Report (PER) has been initiated and an II is in progress.
HRC FORH 366A U.S. N)CLEAR REGULATORY CQBIISSIOH APPROVED BY (WB HO. 3150-0104 (5-92) EXPIRES 5)31/95 ESTIHATED BURDEN PER RESPONSE TO COHPLY llITH THIS INFORHATION COLLECTION REOUEST: 50.0 NRS. FORIIARD COHHENTS REGARDING BURDEN EST IHATE TO TNE INFORHATION AND RECORDS HANAGEHENT BRANCH (HNBB 7714), U.S. NUCLEAR REGULATORY COHMISSION, LICENSEE EVENT REPORT MASNINGTON, DC 20555-0001 ~ AND TO THE PAPERlKNK REDUCTION TEXT CONTINUATION PROJECT (3150-0104), OFFICE 'OF HANAGENENT AND BUDGET/
NASHINGTON DC 20503 FACILITY HAHE (1) DOCKET HWBER (2) LER HOSER (6) PAGE (3)
YEAR SEQUENTIAL REVISION NUHBER NUHBER Browns 'Ferry Unit 2 05000260 93 011 00 6 of 8 TEXT f more s ce is r ired use additions( co ies of NRC Form 366A (17)
B Corrective Actions to Prevent Recurrencec The Unit 2 replacement of the drywell head 0-rings for the Unit 2, Cycle 7 restart will be performed using an approved procedure that addresses the use of RTV. Any further substantial corrective actions that result from the II will be provided in the supplemental report.
VI ~ ADDITIONAL INFORMATION
'A. Failed Com onentsI None Bi Previous LERs on Similar Eventss None VII'ommitments
- 1. The Unit 2 replacement of the drywell head 0-rings for the Unit 2 Cycle 7 restart will be performed using an approved procedure that addresses the use of RTV.
- 2. Documentation will provide instructions on limiting the amount of RTV allowed for the drywell head installation to ensure that does not interfere with the LLRT. This corrective action will be it completed prior to resetting the drywell head'.
- 3. TVA expects to provide a supplemental report by January 25, 1995.
Energy Industry Identification System (EIIS) system and component codes are identified in the text with brackets (e.g., [XX].
0 NRC FORM '366A U.S. WCLEAR REGULATORY CQIIISSIQI APPROVED SY QHI NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO CQiPLY IIITH THIS INFORMATION COLLECTION REQUEST 50.0 HRS FORMARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORHATI OH AHD RECORDS MANAGEMENT LZCENSEE EVENT REPORT BRANCH (NHBB 7714), U.S NUCLEAR REGULATORY CQOIISSIONg TEXT CONTZNUATZON MASHINGTOH, DC 20555-0001, AND TO THE'APERHORK REDUCTION PROJECT (3150-0')04) ~ OFFICE OF MANAGEMENT AND BUDGET/
iIASHINGTOM, DC 20503 FACILITY NAIF (1) DOCKET MINGLER (2) LER IRHSER (6) PAGE (3)
YEAR SEQUENTIAL REVI SI OH NUMBER NUMBER Browne Ferry Unit 2 05000260 93 011 00 7 of 8 TEXT lf more s ce is r ired use additional co ies of MRC Form 366A (17)
NlAIN FLANGE 0-RINGS OUTSIDE INSIDE DRYHELL DRYHELL DRYWELLIIEAD FLANGE 0-RING CONFIGURATION
0 NRC FINDI.365A U S IN)CLEAR REGLRATORY CtlelISSION APPROVED BY tNRI NO 3150-0104 (5-92) EXPIRES 5/31/95 ESTIHATED BURDEN PER RESPONSE To COHPLY WITH THIS INFORNATION COLLECTION REOUEST: 50.0 HRS. FORWARD COHHENTS REGARDING BURDEN EST I HATE To THE INFORHATION AND RECORDS NANAGEHENT LICENSEE EVENT REPORT *BRANCH (NNBB 7714) ~ U.S. NUCLEAR REGULATORY COHHISSION, TEXT CONTINUATZON WASHINGTON, DC 20555-0001 ~ AND To THE PAPERWORK REDUCTION PROJECT (3150 0104) ~ OFFICE OF NANAGEHENT AND BQ)GET, WASHINGTON DC 20503 FACILITY WUK (1) DOCKET NN%ER (2) LER IRISER (6) PAGE (3)
YEAR SEQUENTIAL REVISION NUHBER NUHBER Browne Ferry Unit 2 05000260 93 Oll 00 8 of 8 TEXT If more s ce is r ired use additional co les of NRC Form 366A (17)
U2CG - U2C7 N2 USE COMPARISON - CHART I 600 t
500 400 -;
TECH SPEC LIMIT(542 SCFH/DAY) 4J 300 ~
Lu UZC6 and UZC7 N2 AVERAGE USE (SEE CHART 2)
Q) I 200 -.
tV z
100 0
O N C) A (0 O W CO cv A r) pl DAYS U2CG - U2C7 N2 USE COMPARISON - CHART 2 120 Air compressor problems iU2C7)
U2C7 N2 USE (Actual Average)
,I CI 7) 80 .
U2C7 N2 USE (Assumed Constant Average) 40 z y
~UZC6 N2 USE (Actual Average) iV OAY 1 IU2C6) = 9/I/92 DAYS OAY 1 (U2C7) = 6/1/93
4$