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 ExitedML18038B804 |
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: |
01/13/1997 |
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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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ML18038B803 |
List: |
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References |
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LER-96-007-04, LER-96-7-4, NUDOCS 9701160040 |
Download: ML18038B804 (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
[Table view] |
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NRC FORM 366 U. UCLEAR REGULATORY COMMISSION ROVED BY OMB NO. 3150-0104 (4-95) EXPIRES 04/30/96 ESTIMATED BURDEN PER RESPONSE To COMPLY WITH THIS MANDATORY INFORMATION COLLECTION REQUEST:
50.0 HRS. REPORTED LESSONS LEARNED ARE L1CENSEE EVENT REPORT (LER) INCORPORATED INTO THE LICENSING PROCESS AND FED BACK TO INDUSTRY. FORWARD COMMENTS REGARDING (See reverse for required number of BURDEN ESTIMATE To THE INFORMATION AND RECORDS digits/characters for each block) MANAGEMENT BRANCH IT.6 F33), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555 FAC(UTY NAME (1) DOCKET NUMBER (2) PAGE (3)
Browns Ferry Nuclear Plant (BFN) Unit 3 05000296 1OFB T)TLE (4)
Engineered:Safety Feature actuations resulting from an inadequate planning of a step-text work order.
EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (6)
FAC(UTY NAME DOCKET NUMBER SEQUENTIAL REVISION MONTH DAY YEAR MONTH DAY YEAR NUMBER ~ ~ NUMBER N/A FACILITYNAME DOCKETNUMBER 12 13 96 96 007 00 01 13 97 N/A OPERATING THIS REPORT. IS SUBMITTED FURS UANT To THE REQUIREMENTS OF 10 CFR I): (Check one or more) (11)
MODE (91 N 20.2201 (b) 20.2203(B)(2)(v) 50.73(a)(2)(l) 50.73(B) (2)(viii) 20.2203(B)(1) 20.2203(B)(3)(l) 50.73(a)(2)(ii) 50.73(B) (2)(x)
POWER LEVEL (10) 100 20.2203(B)(2) (I) 20.2203(B)(3)(ii) 50.73(B)(2) (iii) 73.71 20.2203(B) (2) (ii) 20.2203(B)(4) 50.73(B) (2) (iv) OTHER 20.2203(a)(2)(iii) 50.36(c) (1) 50.73(B) (2) (v) Specify In Abs(rec( below or in NRC Form 366A 20.2203(a)(2) (iv) 50.36(c)(2) 50.73(B)(2) (v)))
LICENSEE CONTACT FOR THIS LER (12)
NAME TELEPHONE NUMBER ()no)ude Ares Code)
James E. Wallace, Licensing Engineer (205) 729-7874 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)
REPORTABLE REPORTABLE CAUSE SYSTEM COMPONENT MANUFACrURE R CAUSE SYSTEM COMPONENT MANUFACTURER To NPRDS To NPRDS SUPPLEMENTAL REPORT EXPECTED (14) MONTH DAY YEAR EXPECTED YES SUBMISSION (If yes, complete EXPECTED SUBMISSION DATE).
X NO DATE (15)
ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)
On December 13, 1996, with Units 2 and 3 at approximately 100 percent power and Unit 1 shutdown and defueled, Unit 3 experienced unplanned Engineered Safety Feature actuations when an external 120 VAC power supply tripped the Instrument and control panel breaker during the setting of a limit switch setting on a drywell nitrogen supply valve. This condition initiated primary containment isolation valves, specifically, both and torus hydrogen and oxygen analyzers sample and return lines to isolate. The root cause of this event divisions'rywell was an inadequate planning of a step-text work order in that a step was not properly sequenced in accordance with an approved procedure. The tripped breaker was reset and the LCO condition was exited. Corrective actions taken.to preclude recurrence of this type of event were: 1 the Electrical Maintenance planners will be counselled,
~
and 2. the Maintenance Managment System procedure will be revised.
This report is being submitted in accordance with 10 CFR 50.73 (a)(2)(iv) as any event or condition that caused ESF actuations.
Previous LERs on similar events were: 50-260/88010, 260/90020, and 260/92008 .
970ii60040 970ii3 PDR ADOCK 05000296 8 PDR
~I NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (4-95)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1) DOCKET LER NUMBER (6) PAGE (3)
I NUMBER NUMBER Browns Ferry Unit 3 05000296 2 of 8 96 "- 007 -- 00 more space is require, use a iuona copies o orm PLANT CONDITIONS At the time of discovery on December 13, 1996, Units 2 and 3 were operating at approximately 100 percent power. Unit 1 was shutdown and defueled.
ZZ. DESCR1PTZON OF EVENT Event On December 13, 1996, at 0136 hours0.00157 days <br />0.0378 hours <br />2.248677e-4 weeks <br />5.1748e-5 months <br /> Central Standard Time (CST),
the Unit 3, during the performance of a step-text work order (WO 96-015635-001), the Instrument & Control (I&C) Bus "B" 120 VAC breaker 336 at panel (9-9) [EE] [BKR] to a drywell nitrogen supply valve tripped.
This condition resulted from an external 120 VAC power supply being connected to a circuit that had not been fully isolated during the setting of the limit switches on the drywell nitrogen supply train B Division ZZ solenoid valve [LK] [ISV] (See page 8 of 8). Since the external power supply was attached to a grounded neutral wire, the 120 VAC, 20 amp breaker on panel 9-9 tripped. At that time, both primary containment isolation valves of containment monitoring hydrogen and oxygen analyzers (H202)
[ZK] closed. As a result of isolating the hydrogen analyzers, a Limiting Condition for Operations (LCO) 3.7.H.3 was entered.
At 0137 hours0.00159 days <br />0.0381 hours <br />2.265212e-4 weeks <br />5.21285e-5 months <br />, Operations personnel found that the breaker for the 1&C Panel 9-9 had tripped. At 0139 hours0.00161 days <br />0.0386 hours <br />2.29828e-4 weeks <br />5.28895e-5 months <br />, the breaker was reset, but it tripped again after five seconds. At 0150 hours0.00174 days <br />0.0417 hours <br />2.480159e-4 weeks <br />5.7075e-5 months <br />, the Unit Supervisor (utility, licensed) sent assistant unit operators (AUO) (utility, non-licensed) to investigate the source of the tripped breaker. The AUOs questioned electrical maintenance (EM) personnel (utility, non-licensed) who were setting the limit switches on the drywell nitrogen supply train B Division II solenoid valve. The EMs were requested to stop their work activity and to return the system to the pre-job configuration. At 0159 hours0.00184 days <br />0.0442 hours <br />2.628968e-4 weeks <br />6.04995e-5 months <br />, Operational personnel again closed the breaker. At 0221 hours0.00256 days <br />0.0614 hours <br />3.654101e-4 weeks <br />8.40905e-5 months <br />, the 3A and 3B hydrogen analyzers were returned to service, and the LCO was exited. Plant equipment appeared to have functioned as required.
At 0457 hours0.00529 days <br />0.127 hours <br />7.556217e-4 weeks <br />1.738885e-4 months <br />, a four-hour notification was made to the NRC in accordance with 10 CFR 50.73(b)(2)(ii) . The cause of the event was discovered to be an inadequate planning of a step-text WO being performed by the EMs. At 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br /> CST, the step-text WO was revised to isolate the solenoid rectifier from the ZEC 120 VAC circuit, and the work order was performed without an further problems.
NRC FORM 366A (4-95I
II NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (4-96)
LXCENSEE EVENT 'REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1) DOCKET LER NUMBER (6) PAGE (3)
NUMBER NUMBER
- Browns Ferry Unit 3 05000296 3 of 8 96 -- 007 -- 00 more space is require, use a mone copies o orm HISTORY OF TEMPLATE STEP-TEXT WORK ORDER On June 8, 1990, a step-text WO (WO 90-07108-00) was initiated to perform a baseline inspection of the Unit 2 electrical components of the nitrogen isolation solenoid valve (BFN 2-FSV 084-008D) .
During the planning of the work order that provided steps to disassemble the valve, to reassemble the valve, and to set the limit switches on the valve, the planner decided not to incorporate an isolation step as depicted in an approved site procedure (ECI-0-000-SOL002). At that time, the planner placed an isolation step in the disassembly part of the WO instead of the part where the limit switches are set. This initial WO became a template for succeeding WOs. Consequently, on December 11, 1996, when an electrical maintenance planner was requested to develop:a .step-text WO to disassemble, reassemble, and set the limit switches in support of mechanical maintenance on the nitrogen isolation solenoid valve, the planner reviewed past WOs and selected the template WO.
PERFORMANCE OF WO ON DECEMBER 12 AND 13 1996 The December 12, 1996, day shift performed .the electrical disassembly of the valve to prepare for valve maintenance. Since the isolation step was not performed during the disassembly, the isolation step was marked (N/A) not applicable. On the evening shift, valve repair was completed. The setting of the shift. limit switches was left for the December 13, 1996, midnight When the midnight shift performed a pre-job review, the EMs noticed that all preceding steps were signed or marked with an N/A. As a result of the review, they continued on Step 1.9 in the step-text WO. Step 1.9.5 required a 120 VAC external power supply to be connected to the rectifier circuit to the solenoid valve coil to stroke the valve. Since the circuit was not fully isolated, this connection resulted in connecting 120 VAC to the breaker' neutral wire (grounded) . A resultant overcurrent condition caused the breaker to trip.
REPORTING RE UIREMENTS BFN notified the NRC Operations Center of a four-hour non-emergency report in accordance with 10 CFR 50.72(b) (2) (ii) as an event that results in automatic actuation of any ESF.
Additionally, this report is submitted in accordance with 10 CFR 50.73(a)(2)(iv) as an event that results in automatic actuation of any ESF.
B Ino erable Structures Com onents or S stems that Contributed to the Event:
None.
NRC FORM 366A (4-95)
0 4
. ~
NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISS)ON l4-95)
LXCENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1) DOCKET LER NUMBER (6) PAGE (3)
I NUMBER NUMBER Browns Ferry Unit 3 05000296 4 of 8 96 -- 007 -- 00 more spece is require, use a ruone copies o orm C. Dates and A roximate Times of Ma'or Occurrencess June 8, 1990 Planner initiated a step-text work order to repair 2-FSV-84-008D. Steps in this work order were not consistent with an approved procedure (ECI-0-000-SOL002).
December 11, 1996 At 2205 hours0.0255 days <br />0.613 hours <br />0.00365 weeks <br />8.390025e-4 months <br />, CST Planner wrote a work order using a 1995 work order template derived from the June 1990 work order.
December 13, 1996 At 0136 hours0.00157 days <br />0.0378 hours <br />2.248677e-4 weeks <br />5.1748e-5 months <br />, CST Breaker on Unit 3 I&C Panel 9-'9 tripped.
Unit 3 entered LCO g 3-96-160-3.7.H.3 due to a loss of both hydrogen analyzers.
At 0150 hours0.00174 days <br />0.0417 hours <br />2.480159e-4 weeks <br />5.7075e-5 months <br />, CST Electrical Maintenance personnel returned system to its pre-job configuration.
At 0221 hours0.00256 days <br />0.0614 hours <br />3.654101e-4 weeks <br />8.40905e-5 months <br />, CST Operations personnel returned the 3A and 3B Hydrogen analyzers to service. LCO was exited.
At 0457 hours0.00529 days <br />0.127 hours <br />7.556217e-4 weeks <br />1.738885e-4 months <br />, CST A four-hour NRC notification was made in accordance with 10 CFR 50.72(b)(2)(ii).
At 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br />, CST The WO was revised, and work on the valve was completed without any additional problems.
D. Other S stems or Seconda Functions Affected:
None.
E~ Method of Discove This event was promptly discovered when control room alarms indicated the opening of the IEC panel (9-9) breaker and the isolation of the Unit 3 drywell and torus H202 analyzers.
0 erator Actions s In this event, steps were taken to identify the isolation problems, and maintenance actions were initiated as appropriate.
G. Safet S stem Res onses:
None.
NRC FORM 366A (4-95)
41 NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (4-95)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1) DOCKET LER NUMBER (6) PAGE (3) j NUMBER NUMBER Browns Ferry Unit 3 05000296 5 of 8 96 -- 007 -- 00 more space is require, use a ruona copies o orm III ~ CAUSE OF THE EVENT A. Immediate Causes The immediate cause of the events was a trip of the IRC panel 9-9 120 VAC breaker. This condition resulted in de-energizing primary containment isolation valves.
Specifically, the closure of the isolation valves for the drywell and torus H202 analyzers.
B. Root Cause:
The cause of this event was the result of inadequate planning of a step-text WO. Although an approved procedure had proper sequenced steps to isolate the rectifier circuit of the solenoid valve, the planner of a 1990 WO placed a comparable step in the disassembly part of the step-text WO.
This 1990 step-text WO became a template for succeeding, WO for repairing this type of solenoid valve. The planner who wrote the 1996 WO used a WO that was a template of the 1990 WO. Additionally, the planner and the reviewer made no major changes to the 1996 WO.
C. Contributing Factors:
The Maintenance Management System procedure used by the planners did not clearly identify when and how to use step-text instead of established procedures for work instructions.
IV. ANALYSIS OF THE EVENT The H202 analyzers are used to determine the hydrogen and oxygen concentration in the drywell and torus during normal plant operations or following a LOCA. During a design basis accidents, these analyzers are designed to .isolate as part of a group 6 PCIS isolation. Therefore, the consequence of this event during an accident scenario is minimal.
During the 45 minutes that the analyzers were isolated, the loss of power made two containment ventilation valves inoperable.
These inoperable valves resulted in an inability to vent containment under normal operating conditions. However, containment venting was not required for the duration of this event. Additionally, this inability to vent the containment would not have resulted in a containment overpressure condition since applicable emergency operating instruction appendices provide an alternate means to vent the containment.
Therefore, based on the above, this event did not result in a condition outside the design basis of the plant, nor'id it NRC FORM 366A (4-95)
0 NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (4-95)
LICENSEE EVENT REPORT (LER)
TEXT CONTZNUATZON FACILITY NAME (1) DOCKET LER NUMBER (6) PAGE (3)
NUMBER NUMBER Browns Ferry Unit 3 05000296 6 of 8 96 -- 007 -- 00 more space is require, use a iuona copies o orm adversely affect the health and safety of plant personnel or the public.
V. CORRECTIVE ACTIONS A. Immediate Corrective Actions:
Work order 96-015635-001 was stopped. The system was returned to pre-job configuration. Operations personnel closed the ZEC Panel breaker. Equipment actions appeared to have performed as required. A four-hour notification was made to the NRC in accordance with 10 CFR 50.73(b) (2) (ii) .
Lon -Term Corrective Actions TO Preclude Another Similar Event.
~ The Electrical Maintenance planners will be counselled to be cognizant of the need to consider existing procedural guidance prior to using step-text.
~ The Maintenance Management System procedure will be revised to clearly identify to planners when and how to use step-text instead of established procedures for work instructions.
VI . ADDITIONAL INFORMATION A. Failed Com onents:
None.
B. Previous LERs on Similar Events:
TVA has reviewed previous reportable events have occurred.
BFN LERs to determine if similar Three previous events have occurred:
LER 260 88010 This 1988 LER addressed ineffective preparation and review of a work plan due to personnel error, lack of attention.
The work plan installed a jumper that only bypassed the trip signal but failed to bypass all trip signals in the circuit.
One corrective action was the requirement to review work plans to ensure that sufficient steps were taken to prevent an unplanned ESF actuation. This corrective action would not have precluded this 1996 event in that the planner and reviewer agreed that there was a step in the 1996 WO that would have isolated the circuitry.
NRC FORM 366A (4-95)
I NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION I4.95)
L1CENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1) DOCKET LER NUMBER (6) PAGE (3)
I NUMBER NUMBER Browns Ferry Unit 3 05000296 7 of 8 96 -- 007 -- 00 more space is require, use a niona copies o orm LER 259 90020 This 1990 LER addressed an event that de-energized a 480V shutdown board resulting from a procedure inadequacy and personnel error. The event occurred when the power source from a synchronous timer was attached across the shutdown board' breaker control transfer switch. Specifically, the electrical maintenance procedure did not include any direction on the proper DC power source to be used.
Similarities in the 1990 and the 1996 events was that an external power source was used. However, in. the 1990 event, the procedure did not provide an adequate step to ensure that the external power source would not adversely affect existing equipment. Whereas, this 1996 event the WO had a step for isolating plant equipment from the external source.
Therefore, corrective actions taken in the 1990 event would not have precluded this 1996 event.
LER 260 92008 This 1992 LER addressed the issue that an Operations personnel had inadvertently isolated the hydrogen analyzers without a compensatory sample being taken. The similarity in these LERs was that both LERs addressed isolation of hydrogen analyzers. However, the root cause of the 1992 event was an error on the as constructed drawings. Since a drawing error did not contribute to opening the 1&C panel breaker, corrective actions taken in the 1992 event would not preclude this 1996 event.
VII ~ COMMITMENTS The Electrical Maintenance planners will be counselled to be cognizant of the need to consider existing procedural guidance prior to using step-text. This counseling will be completed by February 14, 1997.
The Maintenance Management System procedure will be revised to clearly identify to planners when and how to use step-text instead of established procedures for work instructions. This revision will be completed by April 16, 1997.
Energy Industry Identification System (EIlS) system and component codes are identified in the text with brackets (e.g., [XX]).
NRC FORM 366A (4-95)
NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION I4.95I LICENSEE EVENT REPORT (LER)
TEXT CONTZNUATZON
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RACZLZTY NAKE (1) DOCKET LER NUMBER (6) PAGE (3)
I I NUMBER NUMBER Browns Ferry Unit 3 05000296 8 Of 8 96 -- 007 -- 00 more space is require, use a iqona copies o orm SIMPUFIED SCHEMATIC DIAGRAM S+CV4440040 During the PerforTnance of WO $ 4<166%~1
{OTHER CIRCUITRY OMITTED FOR CLARITY)
Pulled fuse-y iocllion Connection 120 VAC Points BREAKER IAC BUS 8 338 Solereid Rectier for N 3-FSV~O OVERCURRENT FLOW PATH 120VAC I.IGHTING 8OARD Elecbical Outlet N
NRC FORM 366A {4-95)
0 Ol