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Category:LICENSEE EVENT REPORT (SEE ALSO AO
MONTHYEARML20024J3211994-10-0505 October 1994 LER 94-006-00:on 940909,failure to Perform Slave Relay Test Associated W/One Containment Isolation Valve Due to Improper Work Practices.Reviewed All Slave Relay Test Procedures & Trained All Qualified reviewers.W/941005 Ltr ML20046B5251993-08-0404 August 1993 LER 93-007-00:on 930705,TS Required Surveillance Was Not Performed Because of Inappropriate Action Because of Lack of Attention to Detail.Generated WO 93047633 to Perform Required Surveillance on Unit 1 IPE CA 9010.W/930729 Ltr ML20045H9821993-07-12012 July 1993 LER 93-005-00:on 930612,manual Rt in Unit 1 Occurred Due to Equipment Failure Due to Failure of L-13 Field Cable Between Data Cabinet B & Bulkhead for Undetermined Reasons.Replaced Field cable.W/930709 Ltr ML20045D9681993-06-25025 June 1993 LER 93-006-00:on 930526,discovered That Sample Blower for Radiation Monitor 1 EMF-43B Off & Monitor Declared Inoperable & Ventilation Sys Air Intakes Not Isolated.Caused by Deficient Procedures.Test Procedures Revised ML20045B2811993-06-11011 June 1993 LER 93-004-00:on 930513,both Trains of CR Ventilation Sys Declared Inoperable Due to Equipment Failure.Exact Cause of Failure Could Not Be Determined.Train B Nuclear Svc Water Sys Flow Balance completed.W/930611 Ltr ML20029C2091991-03-21021 March 1991 LER 91-003-00:on 910219,both Trains of Control Room Ventilation Sys Inoperable.Caused by Design Malfunction & Management Deficiency.Temporary Modifications,Removing Automatic Closure Function implemented.W/910321 Ltr ML20028G9561990-09-26026 September 1990 LER 90-025-00:on 900827,Unit 1 Shut Down Because of Unidentified RCS Leakage Exceeding Tech Spec Limits.Caused by Equipment Failure.Procedure AP/1/A/5500/10 Implemented. Valve 1NC-33 Will Be Repacked at Next outage.W/900926 Ltr ML20044A0091990-06-25025 June 1990 LER 90-015-00:on 900524,Tech Spec 3.0.3 Entered Because More than One Power Range Nuclear Instrumentation Channel Exceeded 5% Deviation.Caused by Mgt Deficiency.Boric Acid Added to Coolant sys.W/900625 Ltr ML20043H4991990-06-21021 June 1990 LER 90-012-00:on 900522,loose Matl,Consisting of Masslin Cloths & Stepoff Pad,Discovered in Upper Containment.Caused by Failure to Follow Procedures.Loose Items Removed & Cleanliness Procedures revised.W/900621 Ltr ML20043H2641990-06-20020 June 1990 LER 90-011-00:on 900521,noted That Valve 1RN-69A Auxiliary Feedwater Assured Supply from Train a Nuclear Svc Water Repositioned to Open Position After Start of Pump.Cause Unknown.Pump Shut Down & Valve closed.W/900620 Ltr ML20043F7471990-06-13013 June 1990 LER 90-010-00:on 900427,discovered That Annulus Ventilation & Control Room Ventilation Sys Headers Would Not Operate,As Designed,Under Postulated Operating Conditions. Caused by Design Deficiency.Change submitted.W/900613 Ltr ML20043F5071990-06-11011 June 1990 LER 90-009-00:on 900512,feedwater Isolation Occurred as Result of Steam Generator 1B Reaching hi-hi Level Setpoint of 82% Level.Caused by Inappropriate Action Because of Lack of Attention to Detail.Feedwater Logic reset.W/900611 Ltr ML20043D6541990-05-30030 May 1990 LER 90-007-00:on 881018,during Insp Ice Condenser Basket Found W/Bottom Screws Missing.Caused by Installation Deficiency Because of Improper Matl Selection.Work Request Initiated to Replace Improper screws.W/900530 Ltr ML20043D7121990-05-30030 May 1990 LER 90-006-00:on 900226,discovered Abnormal Degradation on Steel Containment Vessel.Corrosion Caused by Design Deficiency Caused by Unanticipated Environ Interaction. Detailed Insps conducted.W/900529 Ltr ML20043C8041990-05-30030 May 1990 LER 90-008-00:on 900430,radiation Monitor for Contaminated Parts Warehouse Ventilation & Sampler Min Flow Device Declared Inoperable.Caused by Personnel Error.Appropriate Procedures Enhanced to Prevent recurrence.W/900530 Ltr ML20012D1651990-03-19019 March 1990 LER 90-004-00:on 900208,determined That Holes Left in Auxiliary Shutdown Panel Could Allow Water Spray Into Cabinet.Cause Unknown.Holes Covered W/Duct Tape & Repaired. W/900319 Ltr ML20011F4261990-02-16016 February 1990 LER 90-002-00:on 900117,hold Down Screws on Sylvania Contactors in Motor Control Ctrs Found Loose.Caused by Mfg Deficiency.Contactor Screws Tightened.All Hold Down Screws Will Be Replaced W/Another type.W/900223 Ltr ML20006D5571990-02-0707 February 1990 LER 90-001-00:on 900108,reactor Trip Occurred Due to Clogged Strainer on Feedwater Pump a Speed Controller.Caused by Water in Oil Sys.Cause for Water Presence in Sys Unknown. Sludge Minimization Attempts pursued.W/900207 Ltr ML20006A8771990-01-21021 January 1990 LER 89-028-00:on 891204,self-initiated Technical Audit Team Personnel Identified Gap Around Control Room Ventilation Air Handling Unit Access Door.Caused by Possible Const/ Installation Deficiency.Door Sys modified.W/900122 Ltr ML19327C2581989-11-13013 November 1989 LER 89-031-00:on 891012,ac Power Supply Fuse Blew Resulting in Automatic Isolation of Four Outside Air Intakes on Ventilation Sys.Caused by Inappropriate Action.Intake Valves Returned to Svc & Tech Spec 3.3.3.1 exited.W/891113 Ltr ML19324C2031989-11-10010 November 1989 LER 89-024-00:on 890908,MSIV Stroke Timing Periodic Test Performed W/O Air Assistance & Three MSIVs Failed to Close within 5 S.Caused by Brass Guide Screws Excessively Tightened.Set Screws Properly set.W/891106 Ltr ML19324C2011989-10-31031 October 1989 LER 88-019-02:on 880719,damper Compartment Flows Did Not Meet Flow Requirements Due to Closure of Some Sys Dampers. Caused by Defective procedure.As-found Measurements Taken While Operating Fans for Damper positions.W/891030 Ltr ML19327B5611989-10-26026 October 1989 LER 89-030-00:on 890714,visual Insp Revealed 3/4 Inch Open Conduit Connection Which Would Have Prevented Successful Leak Test.Cause Unknown.Connection Removed & Hole Sealed. W/891026 Ltr ML19327B4771989-10-23023 October 1989 LER 89-029-00:on 890922,ESF Actuation Occurred When Diesel Generator 1A Started Due to Momentary Undervoltage Condition on Train a 4,160-volt Essential Switchgear.Cause Unknown. Offsite Power Source Returned to Normal svc.W/891023 Ltr ML19327B1511989-10-19019 October 1989 LER 89-026-00:on 890720,both Trains of Control Area Ventilation Sys Inoperable.Caused by Design Deficiency Because of Unanticipated Interaction of Components.Original Check Damper Reinstalled in Fan on Train B.W/891019 Ltr ML19351A4301989-10-18018 October 1989 LER 89-025-00:on 890918,jumper Came Loose & Inadvertently Made Contact W/Sliding Link B-14 Directly Above Link B-15, Resulting in Turbine Driven Feedwater Pump Automatically Starting.Caused by Inappropriate action.W/891018 Ltr ML19325D4991989-10-16016 October 1989 LER 89-027-00:on 890915,preheaters Did Not Start Because Air Flow Permissive Was Not Made & Cross Connect Dampers Were Closed & Tagged & Ventilation Sys Train a Remained Logged Inoperable.Caused by Design deficiency.W/891016 Ltr ML19325C4871989-09-28028 September 1989 LER 89-018-00:on 890829,both Trains of Control Area Ventilation (VC) & Chilled Water (Yc) Sys Declared Inoperable.Caused by Equipment/Failure Malfunction. Refrigerant Added to Vc/Yc chiller.W/890928 Ltr ML20043D7041989-09-25025 September 1989 LER 89-022-01:on 890826,reactor Trip Occurred Due to Failed Universal Board in Solid State Protection Sys Cabinet A. Caused by Equipment/Malfunction.Universal Board Replaced. W/900530 Ltr ML19325C4731989-09-18018 September 1989 LER 89-015-00:on 890722,discovered That Neutral Pressure Was Best That Could Be Achieved in Some Required Sys Configurations.Caused by Design Deficiency Due to Design Oversight.Outside Air Ref Point installed.W/891004 Ltr ML20024F2791983-08-29029 August 1983 LER 83-066/03L-0:on 830817,invalid Alarm Received for Fire Detection Zone Efa 90 Which Would Not Clear.Caused by Unusual Svc Conditions.Detector Cleaned & replaced.W/830829 Ltr ML20024D8101983-07-29029 July 1983 LER 83-050/03L-0:on 830629,control Area Ventilation Sys Train B Declared Inoperable.Caused by Automatic Reset Preheater Overtemp Cutout Switch Failure.Replacement Switch Will Be installed.W/830729 Ltr ML20024D7531983-07-27027 July 1983 LER 83-048/03L-0:on 830624,control Area Ventilation Sys Train B Declared Inoperable Following Low Refrigerant Temp Alarm Trip of Control Room Chiller B.Caused by Cleaning of Condenser tubes.W/830727 Ltr ML20024D7701983-07-27027 July 1983 LER 83-049/03L-0:on 830624,surveillance Compliance Review Revealed Three Time Response Tests Not Performed.Cause Not Stated.Remaining Channels Will Be Tested During Next refueling.W/830727 Ltr ML20024D8951983-07-27027 July 1983 LER 83-047/03L-0:on 830627,discovered That 18-month Insp of Fire Hose Station 180 Not Performed During Nov 1981.Caused by Order Preventing Personnel from Entering Area Due to High Radiation Levels.Procedural Change instituted.W/830727 Ltr ML20024C4091983-06-28028 June 1983 Updated LER 83-002/03X-1:on 830110,pressurizer Heater Group 1B Failed to Energize in Manual & Declared Inoperable.Heat Damage Found at Heat Dissipating Resistor Connections.Caused by Design Defect in Contactor Coil circuit.W/830628 Ltr ML20024C3941983-06-28028 June 1983 LER 83-035/03L-0:on 830515,pressurizer Heater Group 1B Failed to Energize in Manual & Declared Inoperable Per Tech Spec 3.4.3.Caused by Blown Fuse in Heater Contactor Control Circuit.Fuse replaced.W/830628 Ltr ML20024C0001983-06-27027 June 1983 LER 83-030/01T-0:on 830526,discovered Monthly Test of Containment Pressure Control Sys Failed to Satisfy Surveillance Requirements to Check Permissive/Termination Setpoint Accuracy.Alarm Modules recalibr.W/830627 Ltr ML20023C4691983-05-0505 May 1983 LER 83-017/03L-0:on 830405,during Draining of Refueling Cavity RHR (Nd) Pumps Began to Cavitate & Eventually Both Nd Pumps Stopped.Caused by Level Gauge Isolation.Cavity Refilled.Nd Sys Vented.Procedures Revised ML20028E0131983-01-10010 January 1983 LER 82-081/03L-0:on 821211,lower Personnel Airlock Declared Inoperable After Reactor Door Found Partially Closed W/Small Seal Ruptured & Large Seal Inflated.Cause Not Known.Seal Not Designed to Withstand Unrestrained Inflationary Forces ML20028A5301982-11-10010 November 1982 LER 82-073/03L-0:on 820403,during QA Audit of Test Procedures,Incore & Nuclear Instrumentation Sys Correlation Monthly Check Found Not Performed.Caused by Incorrect Test Schedule ML20027D3351982-10-22022 October 1982 LER 82-071/03L-0:on 820922,motor Control Ctr Lemxd Lost Power Causing Temporary Inoperability of Several Essential Sys/Components.Caused by Automatic Trip of Feeder Breaker. Breaker Reset & Closed.Power Restored ML20027B5051982-09-10010 September 1982 LER 82-067/03L-0:on 820813,two Auxiliary Feedwater Pump Turbine Low Suction Pressure Switches Failed to Perform During Functional Test.Caused by Switches Being Out of Calibr,Possibly Due to Instrument Drift or Misadjustment ML20027B5521982-09-0808 September 1982 LER 82-064/03L-0:on 820809,vent Flow Monitor Indicated Zero W/Vent in Operation During Process of Returning to Mode 1. Caused by Out of Calibr Differential Pressure Transmitter Due to Instrument Drift.Transmitter Recalibr ML20052H5831982-05-10010 May 1982 LER 82-027/03L-0:on 820326,one Channel of Position Indication for RCS Power Operated Relief Valves NC-32 & NC-36 Declared Inoperable When Closed Indicator Lights Failed.Caused by Loose Fitting Bulb Due to Crack in Socket ML20052G6791982-05-0707 May 1982 LER 82-030/01T-0:on 820423,diesel Generator 1A Declared Inoperable After Failing to Start for Periodic Test.Caused by Failure of Station Design Change Implementation Program to Control Work on Station Mods ML20052H7421982-05-0707 May 1982 LER 82-031/03L-0:on 820408,boric Acid Transfer Pump a Failed to Perform at Capacity & Declared Inoperable.Caused by Reverse Rotation Due to Improperly Connected Windings. Personnel Counseled & Maint Routine Modified ML20052H7481982-05-0606 May 1982 LER 82-029/03L-0:on 820402,investigation of Power Operated Relief Valve (PORV) & Pressurizer Code Safety Discharge Line High Temp Alarms Revealed Indications of Leakage for PORV NC-34.Cause Undetermined.Valve Will Be Repaired ML20052H6091982-04-30030 April 1982 LER 82-028/03L-0:on 820401,during Mode 1 Operation,Radiation Monitors EMF-31 & EMF-33 Lost Power.Caused by Monitor EMF-46 Tripping Circuit Breaker Due to Direct Short Across Power bulb.EMF-46 Isolated & EMF-31 & 33 Returned to Svc ML20052G3611982-04-29029 April 1982 LER 82-025/03L-0:on 820318,vol Control Tank Makeup Frequency Increased & Containment Floor & Equipment Sump 1A Level Increased During RCS Leak Test.Caused by Failure to Verify Isolation Valves Closed Due to Procedural Deficiency 1994-10-05
[Table view] Category:RO)
MONTHYEARML20024J3211994-10-0505 October 1994 LER 94-006-00:on 940909,failure to Perform Slave Relay Test Associated W/One Containment Isolation Valve Due to Improper Work Practices.Reviewed All Slave Relay Test Procedures & Trained All Qualified reviewers.W/941005 Ltr ML20046B5251993-08-0404 August 1993 LER 93-007-00:on 930705,TS Required Surveillance Was Not Performed Because of Inappropriate Action Because of Lack of Attention to Detail.Generated WO 93047633 to Perform Required Surveillance on Unit 1 IPE CA 9010.W/930729 Ltr ML20045H9821993-07-12012 July 1993 LER 93-005-00:on 930612,manual Rt in Unit 1 Occurred Due to Equipment Failure Due to Failure of L-13 Field Cable Between Data Cabinet B & Bulkhead for Undetermined Reasons.Replaced Field cable.W/930709 Ltr ML20045D9681993-06-25025 June 1993 LER 93-006-00:on 930526,discovered That Sample Blower for Radiation Monitor 1 EMF-43B Off & Monitor Declared Inoperable & Ventilation Sys Air Intakes Not Isolated.Caused by Deficient Procedures.Test Procedures Revised ML20045B2811993-06-11011 June 1993 LER 93-004-00:on 930513,both Trains of CR Ventilation Sys Declared Inoperable Due to Equipment Failure.Exact Cause of Failure Could Not Be Determined.Train B Nuclear Svc Water Sys Flow Balance completed.W/930611 Ltr ML20029C2091991-03-21021 March 1991 LER 91-003-00:on 910219,both Trains of Control Room Ventilation Sys Inoperable.Caused by Design Malfunction & Management Deficiency.Temporary Modifications,Removing Automatic Closure Function implemented.W/910321 Ltr ML20028G9561990-09-26026 September 1990 LER 90-025-00:on 900827,Unit 1 Shut Down Because of Unidentified RCS Leakage Exceeding Tech Spec Limits.Caused by Equipment Failure.Procedure AP/1/A/5500/10 Implemented. Valve 1NC-33 Will Be Repacked at Next outage.W/900926 Ltr ML20044A0091990-06-25025 June 1990 LER 90-015-00:on 900524,Tech Spec 3.0.3 Entered Because More than One Power Range Nuclear Instrumentation Channel Exceeded 5% Deviation.Caused by Mgt Deficiency.Boric Acid Added to Coolant sys.W/900625 Ltr ML20043H4991990-06-21021 June 1990 LER 90-012-00:on 900522,loose Matl,Consisting of Masslin Cloths & Stepoff Pad,Discovered in Upper Containment.Caused by Failure to Follow Procedures.Loose Items Removed & Cleanliness Procedures revised.W/900621 Ltr ML20043H2641990-06-20020 June 1990 LER 90-011-00:on 900521,noted That Valve 1RN-69A Auxiliary Feedwater Assured Supply from Train a Nuclear Svc Water Repositioned to Open Position After Start of Pump.Cause Unknown.Pump Shut Down & Valve closed.W/900620 Ltr ML20043F7471990-06-13013 June 1990 LER 90-010-00:on 900427,discovered That Annulus Ventilation & Control Room Ventilation Sys Headers Would Not Operate,As Designed,Under Postulated Operating Conditions. Caused by Design Deficiency.Change submitted.W/900613 Ltr ML20043F5071990-06-11011 June 1990 LER 90-009-00:on 900512,feedwater Isolation Occurred as Result of Steam Generator 1B Reaching hi-hi Level Setpoint of 82% Level.Caused by Inappropriate Action Because of Lack of Attention to Detail.Feedwater Logic reset.W/900611 Ltr ML20043D6541990-05-30030 May 1990 LER 90-007-00:on 881018,during Insp Ice Condenser Basket Found W/Bottom Screws Missing.Caused by Installation Deficiency Because of Improper Matl Selection.Work Request Initiated to Replace Improper screws.W/900530 Ltr ML20043D7121990-05-30030 May 1990 LER 90-006-00:on 900226,discovered Abnormal Degradation on Steel Containment Vessel.Corrosion Caused by Design Deficiency Caused by Unanticipated Environ Interaction. Detailed Insps conducted.W/900529 Ltr ML20043C8041990-05-30030 May 1990 LER 90-008-00:on 900430,radiation Monitor for Contaminated Parts Warehouse Ventilation & Sampler Min Flow Device Declared Inoperable.Caused by Personnel Error.Appropriate Procedures Enhanced to Prevent recurrence.W/900530 Ltr ML20012D1651990-03-19019 March 1990 LER 90-004-00:on 900208,determined That Holes Left in Auxiliary Shutdown Panel Could Allow Water Spray Into Cabinet.Cause Unknown.Holes Covered W/Duct Tape & Repaired. W/900319 Ltr ML20011F4261990-02-16016 February 1990 LER 90-002-00:on 900117,hold Down Screws on Sylvania Contactors in Motor Control Ctrs Found Loose.Caused by Mfg Deficiency.Contactor Screws Tightened.All Hold Down Screws Will Be Replaced W/Another type.W/900223 Ltr ML20006D5571990-02-0707 February 1990 LER 90-001-00:on 900108,reactor Trip Occurred Due to Clogged Strainer on Feedwater Pump a Speed Controller.Caused by Water in Oil Sys.Cause for Water Presence in Sys Unknown. Sludge Minimization Attempts pursued.W/900207 Ltr ML20006A8771990-01-21021 January 1990 LER 89-028-00:on 891204,self-initiated Technical Audit Team Personnel Identified Gap Around Control Room Ventilation Air Handling Unit Access Door.Caused by Possible Const/ Installation Deficiency.Door Sys modified.W/900122 Ltr ML19327C2581989-11-13013 November 1989 LER 89-031-00:on 891012,ac Power Supply Fuse Blew Resulting in Automatic Isolation of Four Outside Air Intakes on Ventilation Sys.Caused by Inappropriate Action.Intake Valves Returned to Svc & Tech Spec 3.3.3.1 exited.W/891113 Ltr ML19324C2031989-11-10010 November 1989 LER 89-024-00:on 890908,MSIV Stroke Timing Periodic Test Performed W/O Air Assistance & Three MSIVs Failed to Close within 5 S.Caused by Brass Guide Screws Excessively Tightened.Set Screws Properly set.W/891106 Ltr ML19324C2011989-10-31031 October 1989 LER 88-019-02:on 880719,damper Compartment Flows Did Not Meet Flow Requirements Due to Closure of Some Sys Dampers. Caused by Defective procedure.As-found Measurements Taken While Operating Fans for Damper positions.W/891030 Ltr ML19327B5611989-10-26026 October 1989 LER 89-030-00:on 890714,visual Insp Revealed 3/4 Inch Open Conduit Connection Which Would Have Prevented Successful Leak Test.Cause Unknown.Connection Removed & Hole Sealed. W/891026 Ltr ML19327B4771989-10-23023 October 1989 LER 89-029-00:on 890922,ESF Actuation Occurred When Diesel Generator 1A Started Due to Momentary Undervoltage Condition on Train a 4,160-volt Essential Switchgear.Cause Unknown. Offsite Power Source Returned to Normal svc.W/891023 Ltr ML19327B1511989-10-19019 October 1989 LER 89-026-00:on 890720,both Trains of Control Area Ventilation Sys Inoperable.Caused by Design Deficiency Because of Unanticipated Interaction of Components.Original Check Damper Reinstalled in Fan on Train B.W/891019 Ltr ML19351A4301989-10-18018 October 1989 LER 89-025-00:on 890918,jumper Came Loose & Inadvertently Made Contact W/Sliding Link B-14 Directly Above Link B-15, Resulting in Turbine Driven Feedwater Pump Automatically Starting.Caused by Inappropriate action.W/891018 Ltr ML19325D4991989-10-16016 October 1989 LER 89-027-00:on 890915,preheaters Did Not Start Because Air Flow Permissive Was Not Made & Cross Connect Dampers Were Closed & Tagged & Ventilation Sys Train a Remained Logged Inoperable.Caused by Design deficiency.W/891016 Ltr ML19325C4871989-09-28028 September 1989 LER 89-018-00:on 890829,both Trains of Control Area Ventilation (VC) & Chilled Water (Yc) Sys Declared Inoperable.Caused by Equipment/Failure Malfunction. Refrigerant Added to Vc/Yc chiller.W/890928 Ltr ML20043D7041989-09-25025 September 1989 LER 89-022-01:on 890826,reactor Trip Occurred Due to Failed Universal Board in Solid State Protection Sys Cabinet A. Caused by Equipment/Malfunction.Universal Board Replaced. W/900530 Ltr ML19325C4731989-09-18018 September 1989 LER 89-015-00:on 890722,discovered That Neutral Pressure Was Best That Could Be Achieved in Some Required Sys Configurations.Caused by Design Deficiency Due to Design Oversight.Outside Air Ref Point installed.W/891004 Ltr ML20024F2791983-08-29029 August 1983 LER 83-066/03L-0:on 830817,invalid Alarm Received for Fire Detection Zone Efa 90 Which Would Not Clear.Caused by Unusual Svc Conditions.Detector Cleaned & replaced.W/830829 Ltr ML20024D8101983-07-29029 July 1983 LER 83-050/03L-0:on 830629,control Area Ventilation Sys Train B Declared Inoperable.Caused by Automatic Reset Preheater Overtemp Cutout Switch Failure.Replacement Switch Will Be installed.W/830729 Ltr ML20024D7531983-07-27027 July 1983 LER 83-048/03L-0:on 830624,control Area Ventilation Sys Train B Declared Inoperable Following Low Refrigerant Temp Alarm Trip of Control Room Chiller B.Caused by Cleaning of Condenser tubes.W/830727 Ltr ML20024D7701983-07-27027 July 1983 LER 83-049/03L-0:on 830624,surveillance Compliance Review Revealed Three Time Response Tests Not Performed.Cause Not Stated.Remaining Channels Will Be Tested During Next refueling.W/830727 Ltr ML20024D8951983-07-27027 July 1983 LER 83-047/03L-0:on 830627,discovered That 18-month Insp of Fire Hose Station 180 Not Performed During Nov 1981.Caused by Order Preventing Personnel from Entering Area Due to High Radiation Levels.Procedural Change instituted.W/830727 Ltr ML20024C4091983-06-28028 June 1983 Updated LER 83-002/03X-1:on 830110,pressurizer Heater Group 1B Failed to Energize in Manual & Declared Inoperable.Heat Damage Found at Heat Dissipating Resistor Connections.Caused by Design Defect in Contactor Coil circuit.W/830628 Ltr ML20024C3941983-06-28028 June 1983 LER 83-035/03L-0:on 830515,pressurizer Heater Group 1B Failed to Energize in Manual & Declared Inoperable Per Tech Spec 3.4.3.Caused by Blown Fuse in Heater Contactor Control Circuit.Fuse replaced.W/830628 Ltr ML20024C0001983-06-27027 June 1983 LER 83-030/01T-0:on 830526,discovered Monthly Test of Containment Pressure Control Sys Failed to Satisfy Surveillance Requirements to Check Permissive/Termination Setpoint Accuracy.Alarm Modules recalibr.W/830627 Ltr ML20023C4691983-05-0505 May 1983 LER 83-017/03L-0:on 830405,during Draining of Refueling Cavity RHR (Nd) Pumps Began to Cavitate & Eventually Both Nd Pumps Stopped.Caused by Level Gauge Isolation.Cavity Refilled.Nd Sys Vented.Procedures Revised ML20028E0131983-01-10010 January 1983 LER 82-081/03L-0:on 821211,lower Personnel Airlock Declared Inoperable After Reactor Door Found Partially Closed W/Small Seal Ruptured & Large Seal Inflated.Cause Not Known.Seal Not Designed to Withstand Unrestrained Inflationary Forces ML20028A5301982-11-10010 November 1982 LER 82-073/03L-0:on 820403,during QA Audit of Test Procedures,Incore & Nuclear Instrumentation Sys Correlation Monthly Check Found Not Performed.Caused by Incorrect Test Schedule ML20027D3351982-10-22022 October 1982 LER 82-071/03L-0:on 820922,motor Control Ctr Lemxd Lost Power Causing Temporary Inoperability of Several Essential Sys/Components.Caused by Automatic Trip of Feeder Breaker. Breaker Reset & Closed.Power Restored ML20027B5051982-09-10010 September 1982 LER 82-067/03L-0:on 820813,two Auxiliary Feedwater Pump Turbine Low Suction Pressure Switches Failed to Perform During Functional Test.Caused by Switches Being Out of Calibr,Possibly Due to Instrument Drift or Misadjustment ML20027B5521982-09-0808 September 1982 LER 82-064/03L-0:on 820809,vent Flow Monitor Indicated Zero W/Vent in Operation During Process of Returning to Mode 1. Caused by Out of Calibr Differential Pressure Transmitter Due to Instrument Drift.Transmitter Recalibr ML20052H5831982-05-10010 May 1982 LER 82-027/03L-0:on 820326,one Channel of Position Indication for RCS Power Operated Relief Valves NC-32 & NC-36 Declared Inoperable When Closed Indicator Lights Failed.Caused by Loose Fitting Bulb Due to Crack in Socket ML20052G6791982-05-0707 May 1982 LER 82-030/01T-0:on 820423,diesel Generator 1A Declared Inoperable After Failing to Start for Periodic Test.Caused by Failure of Station Design Change Implementation Program to Control Work on Station Mods ML20052H7421982-05-0707 May 1982 LER 82-031/03L-0:on 820408,boric Acid Transfer Pump a Failed to Perform at Capacity & Declared Inoperable.Caused by Reverse Rotation Due to Improperly Connected Windings. Personnel Counseled & Maint Routine Modified ML20052H7481982-05-0606 May 1982 LER 82-029/03L-0:on 820402,investigation of Power Operated Relief Valve (PORV) & Pressurizer Code Safety Discharge Line High Temp Alarms Revealed Indications of Leakage for PORV NC-34.Cause Undetermined.Valve Will Be Repaired ML20052H6091982-04-30030 April 1982 LER 82-028/03L-0:on 820401,during Mode 1 Operation,Radiation Monitors EMF-31 & EMF-33 Lost Power.Caused by Monitor EMF-46 Tripping Circuit Breaker Due to Direct Short Across Power bulb.EMF-46 Isolated & EMF-31 & 33 Returned to Svc ML20052G3611982-04-29029 April 1982 LER 82-025/03L-0:on 820318,vol Control Tank Makeup Frequency Increased & Containment Floor & Equipment Sump 1A Level Increased During RCS Leak Test.Caused by Failure to Verify Isolation Valves Closed Due to Procedural Deficiency 1994-10-05
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217G7951999-09-30030 September 1999 Monthly Operating Repts for Sept 1999 for McGuire Nuclear Station,Units 1 & 2 ML20217F3661999-09-22022 September 1999 Rev 18 to McGuire Unit 1 Cycle 14 Colr ML20212D1911999-09-20020 September 1999 SER Accepting Exemption from Certain Requirements of 10CFR50,App A,General Design Criterion 57 Closed System Isolation Valves for McGuire Nuclear Station,Units 1 & 2 ML20216E8851999-08-31031 August 1999 Monthly Operating Repts for Aug 1999 for McGuire Nuclear Station,Units 1 & 2 ML20211B1281999-08-31031 August 1999 Dynamic Rod Worth Measurement Using Casmo/Simulate ML20217G8101999-08-31031 August 1999 Revised Monthly Operating Repts for Aug 1999 for McGuire Nuclear Station,Unit 1 & 2 ML20211G5261999-08-24024 August 1999 SER Accepting Approval of Second 10-year Interval Inservice Insp Program Plan Request for Relief 98-004 for Plant,Unit 1 ML20211F3441999-08-17017 August 1999 Updated non-proprietary Page 2-4 of TR DPC-NE-2009 ML20210S2371999-07-31031 July 1999 Monthly Operating Repts for July 1999 for McGuire Nuclear Station,Units 1 & 2 ML20216E8951999-07-31031 July 1999 Revised Monthly Operating Repts for July 1999 for McGuire Nuclear Station,Units 1 & 2 ML20209E4361999-07-0909 July 1999 SER Agreeing with Licensee General Interpretation of TS LCO 3.0.6,but Finds No Technical Basis or Guidance That Snubbers Could Be Treated as Exception to General Interpretation ML20196K6631999-07-0707 July 1999 Safety Evaluation Supporting Licensee 990520 Position Re Inoperable Snubbers ML20209H1631999-06-30030 June 1999 Monthly Operating Repts for June 1999 for McGuire Nuclear Station,Units 1 & 2 ML20210S2491999-06-30030 June 1999 Revised Monthly Operating Rept for June 1999 for McGuire Nuclear Station,Units 1 & 2 ML20209H1731999-05-31031 May 1999 Revised Monthly Operating Rept for May 1999 for McGuire Nuclear Station,Units 1 & 2 ML20206T4771999-05-31031 May 1999 Rev 3 to UFSAR Chapter 15 Sys Transient Analysis Methodology ML20196L1881999-05-31031 May 1999 Non-proprietary Rev 1 to DPC-NE-3004, Mass & Energy Release & Containment Response Methodology ML20195K3691999-05-31031 May 1999 Monthly Operating Repts for May 1999 for McGuire Nuclear Station,Units 1 & 2 ML20206N3511999-05-11011 May 1999 Safety Evaluation Accepting Licensee Response to GL 96-05, Periodic Verification of Design-Basis Capability of Safety- Related Movs ML20195K3761999-04-30030 April 1999 Revised MORs for Apr 1999 for McGuire Nuclear Station,Units 1 & 2 ML20206R0891999-04-30030 April 1999 Monthly Operating Repts for Apr 1999 for McGuire Nuclear Station,Units 1 & 2 ML20205L2341999-04-0505 April 1999 SFP Criticality Analysis ML20206R0931999-03-31031 March 1999 Revised Monthly Repts for Mar 1999 for McGuire Nuclear Station,Units 1 & 2 ML20205P8991999-03-31031 March 1999 Monthly Operating Repts for Mar 1999 for McGuire Nuclear Station,Units 1 & 2 ML20205C4171999-03-25025 March 1999 Special Rept 99-02:on 801027,Commission Approved for publication,10CFR50.48 & 10CFR50 App R Delineating Certain Fire Protection Provisions for Nuclear Power Plants Licensed to Operate Prior to 790101.Team Draft Findings Reviewed ML20207K2051999-03-0505 March 1999 Special Rept 99-01:on 990128,DG Tripped After 2 H of Operation During Loaded Operation for Monthly Test.Caused by Several Components That Were Degraded or Had Intermittent Problems.Parts Were Replaced & Initial Run Was Performed ML20204C8911999-02-28028 February 1999 Monthly Operating Repts for Feb 1999 for McGuire Nuclear Station,Units 1 & 2 ML20205P9021999-02-28028 February 1999 Revised Monthly Operating Repts for Feb 1999 for McGuire Nuclear Station,Units 1 & 2 ML20204C8961999-01-31031 January 1999 Revised Monthly Operating Repts for Jan 1999 for McGuire Nuclear Station,Units 1 & 2 ML20199E0301998-12-31031 December 1998 Monthly Operating Repts for Dec 1998 for McGuire Nuclear Station,Units 1 & 2 ML20216F9931998-12-31031 December 1998 Piedmont Municipal Power Agency 1998 Annual Rept ML20198A4481998-12-11011 December 1998 Safety Evaluation Concluding That for Relief Request 97-004, Parts 1 & 2,ASME Code Exam Requirements Are Impractical. Request for Relief & Alternative Imposed,Granted ML20198D7561998-11-30030 November 1998 Monthly Operating Repts for Nov 1998 for McGuire Nuclear Station,Units 1 & 2 ML20199E0491998-11-30030 November 1998 Revised Monthly Operating Rept for Nov 1998 for McGuire Nuclear Station,Units 1 & 2 Re Personnel Exposure ML20199E9651998-11-24024 November 1998 Rev 1 to ATI-98-012-T005, DPC Evaluation of McGuire Unit 1 Surveillance Weld Data Credibility ML20196D4171998-11-24024 November 1998 Special Rept 98-02:on 981112,failure to Implement Fire Watches in Rooms Containing Inoperable Fire Barrier Penetrations,Was Determined.Repair of Affected Fire Barriers in Progress ML20196G0581998-11-0606 November 1998 Rev 17 to COLR Cycle 13 for McGuire Unit 1 ML20196G0761998-11-0606 November 1998 Rev 15 to COLR Cycle 12 for McGuire Unit 2 ML20198D7771998-10-31031 October 1998 Revised Monthly Operating Rept for Oct 1998 for McGuire Nuclear Station,Units 1 & 2 ML20195E5961998-10-31031 October 1998 Monthly Operating Repts for Oct 1998 for McGuire Nuclear Station,Units 1 & 2 ML20154L6251998-09-30030 September 1998 Monthly Operating Repts for Sept 1998 for McGuire Nuclear Station,Units 1 & 2 ML20195E6021998-09-30030 September 1998 Revised Monthly Operating Rept for Sept 1998 for McGuire Nuclear Station,Units 1 & 2 ML20154B4131998-09-22022 September 1998 Rev 0 to ISI Rept for McGuire Nuclear Unit 1 Twelfth Refueling Outage ML20151W3521998-09-0808 September 1998 Special Rept 98-01:on 980819,maint Could Not Be Performed on FPS Due to Isolation Boundary Leakage.Caused by Inadequate Info Provided in Fire Impairment Plan.Isolated Portion of FPS Was Returned to Svc ML20154L6321998-08-31031 August 1998 Rev 1 to MOR for Aug 1998 for McGuire Nuclear Station,Unit 1 ML20153B3741998-08-31031 August 1998 Monthly Operating Repts for Aug 1998 for McGuire Nuclear Station,Units 1 & 2 ML20236U1601998-07-31031 July 1998 Non-proprietary DPC-NE-2009, DPC W Fuel Transition Rept ML20237B2381998-07-31031 July 1998 Monthly Operating Repts for July 1998 for McGuire Nuclear Station,Units 1 & 2 ML20153B3931998-07-31031 July 1998 Revised Monthly Operating Repts for Jul 1998 for McGuire Nuclear Station,Units 1 & 2 ML20236P0451998-07-0808 July 1998 Part 21 Rept Re non-conformance & Potential Defect in Component of Nordberg Model FS1316HSC Standby Dg.Caused by Outer Spring Valves Mfg from Matl That Did Not Meet Specifications.Will Furnish Written Rept within 60 Days 1999-09-30
[Table view] |
Text
.- .. 11 l Duke krr Cwnpany (704pn.mm ,
AcGwre Nuclear Stoiwn 12M Hagm ferry M> art Huetmntle, AC: Mig &985 DUKE POWER March 21, 1991 U.S. Nuclear Regulatory Commission Document Control Desk Washingtont D.C. 20555
Subject:
McGuire Nuclear Station Unit I and 2 Docket No. 50-369 Licensee Event Report 369/91-03 Gentlement Pursuant to 10 CFR 50.73 Sections (a)(1) and (d), attached is Licensee Event
. Report 369/91-03 concerning both trains of the Control Room Ventilation system being inoperable because of a Design Deficiency. This report is being submitted in accordance with 10 CFR 50.73(a)(2)(v) and (a)(2)(vii). This event is considered to be of no significance with respect to the health and safety of the public.
Very truly yours, r} A f tCw T.L. McConnell DVE/ADJ/cb1 Attachment xc: Mr. S.D. Ebneter Mr. Tim Reed Administrator, Region II U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Ccmmission Office of Nuclear Reketor Regulation 101 Marietta St. , NW, S' ate 2900 Washington, D.C. 2055'S Atlanta, GA 30323 Mr. P.K. Van Doorn INPO Records Center NRC Resident Inspector Suite 1500 McGuire Nuclear Station 1100 circle 75 Parkway Atlanta, GA 30339 M&M Nuclear Consultants 1221 Avenue of the Americas New York, NY 10020
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"'*Both Trains Of The Control Room Ventilation System Were Inoperable Because Of A Desien Deficiency And "fanacement Deficience tythT oaf t sti LtR Nuwata 46 AleOmi Da f t Ifi Of wt a f acettfits inevotvt0 its WONTw DAv vtam vtaa $N U .'" $*M v0%f CAv 'IA* i . = ' r N avt s Doc a t f %vvetie s:
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,il #f res ee-peeve f pfC7f0 $US4HS3sO% CA Tri NO g g l AS$7 A ACT / Led so 7400 aparat e e escre.aete'r Mte#4 sme e taeve troematte* per (18e On February 18, 1991,- Design Engineering (DE) personnel were performing a review of Nuclear Station Modification (NSM) MG-52065 to examine recommended additions to the NSM package. During the course of the' review, DE personnel reevaluated the fact that loss of non-essential electrical power to chlorine detectors and radiation monitors associated with the Control Area Ventilation (VC)-system would cause the Outside Air Intake Isolation valves for the VC system to close and that they could not be reopened from the Control Room.
It was then determined that compensatory actions in place could not be achieved within the timing requirements for the assumptions of the Control Room dose analysis. Subsequently, at 2140, on February 19, 1991, both trains-of the VC system were declared inoperable and Technical Specification (TS)
Action statement 3.0.3 was entered for both units. A temporary modification was initiated to remove the automatic closure function from the radiation monitors and chlorine detectors. Also, changes to the procedures for responses to high chlorine or radiation alarms were initiated. At 0245, ou February 20, the modification,and procedure changes were completed and TS Action Statement 3.0.3 was exited. Unit I and Unit 2 were in Mode 1 (Power Operation) at 100 percent power at the time the event occurred. This event is assigned a cause of Design Oversight and a contributing cause of Management Deficiency. Appropriate modifications and procedure changes will be implemented to resolve the problem.
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EVALUA. ION:
Background
There + wc independent trains of the-VC [EIIS:VI] and Chilled Water (YC)
[EIIG:KL systems which are designed to maintain a habitable environment in
~
the Centrol Room [EIIS:NA) during normal and accident conditions. Based on the-hab.tability requirements as defined in the Final-Safety Analysis Report (FSAR) criteria,=the systi_m is designed as an Engineer.3 Safeguards features
[EIIS:JE] systeu with absolute and carbon filtration (EIIS:FLT]-in the outside air intakes and with equipment redundancies for use as conditions require. The Control Room is designed to be maintained at a positive pressure of >/= 0.125 inches water gauge (w.g.), relative to outside i atmospheric pressure during an accident to prevent entry of contaminants.
~Two.100 percent capacity Outside Air Pressure Filter Trains pressurize the
~
-Control Room by providing approximately 2000 cfm of filtered outside air.
TS Bases'3/4.7.6, VC system, states, in part, that t M operability of the VC system ensures- that the Control Room will remain habitable .for Operations personnel duringLand following all credible accident conditions. The operability of this system in conjunction with. Control Rcom design provisions :
is based on limiting the radiation exposure to personnel occupying the Control Room to 5 rem or less whole body, or its-equivalent. This limitation is- consistent with the requirements of General Design Criterion 19 (GDC-19) of - Appendix A, Code of Federal: Regulations, Title 10, Part .50 (10 CFR 50).
FSAR Section 15.6.4.3, Environmental Consequences for Loss-Of-Coolant 1 Accidents, Control Room Operatoc Dose, states, in part,- that the l maximum postulated dose to a Coatrol Room 0perator is determined based on the.
releases of a Design Basis Accident.' The offsite radiological consequences are . calculated based on certain assumptions and parameters. ::hich include that-the unfiltered.inleakage into the Control Room is 10 cfm.
- The- VC Lsystem has two outside air intake structures [EIIS:NN] for each train.
-Each structure is monitored by a Radiation Monitor (EIIS: MON] for the presence of radiation and has two redundant isolation valves [EIIS:ISV).
When a radiation signal:is received by either Control Room Outside Air Intake
- Radiation Monitors,1 EMF-43A or 1 EMF-43B, the intake which is the source of
-contamination automatically closes. Should both intake.s close, the operator will override the-ir.ake radiation monitors and by inspection of.the Control-Room readouts, opra the-unit intakes with least radiation. This will ensure
_ pressurization u the Control Room at all times. i
-Chlorine Detectors [EIIS:DET] monitor the outside air intake structures of the VC system for the presence of chlorine gas. Each structure is monitored by one detector and has two redundant isolation valves. If gas is detected by either detector of the train, the train intake structures will be automatically secured by means of closing four intake isolation valves and a local / remote alarm [EIIS: ALM] will be generated. The major parts of a l
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- Act ist yo "GP ?M,7; McGuire Nuclear Station, Unit 1 olsjolojol3lt,9 9l1 0l0j3 O;O l3 os l7 mi e . wc wu. ein chlorine detector are the electrolyte tank (Ells:TK] that houses a wick, a blower [ Ells:BLO) unit, and an electronic unit.
Description of Event In March of 1989, Self Initiated Technical Audit (SITA) 89-02 (MC) of the VC system was conducted at McGuire. During the course of this audit, it was found that the single failure of a non-essential electrical circuit for the chlorine detectors associated with the VC system will render the system inoperable by causing all e.ight outside air intake isolation valves to close.
L e closing of these valves will prevent pressurization of the Control Room which is in violation of TS requirements. Also, 10CFR50, Appendix A, j Criterion 24, requires that a safety related system be protected from the effects of a single failure. The results of the investigation conducted at the time of the finding stated the following:
- 1. Root Cause(s) for the_ findings:
At the time the Chlorine Detectors were purchased for McGuire, safety related detectors were unavailable. Chlorine protection wo considered a non-safety function and McGuire was licensed with non-nafety chlorine detectors.
Anytime non safety instrumentatics ic used to control a r efety component, a failure mode on loss of power to the non-sa'ety instrumentation must be selected. In this case, the VC _ntake valves close on loss of power to the chlorine detectors. Although this presents a problem be:ause outside air would not be available
- for pressurizing the Control Room, closing the valves is the safe position for chlorine. protection. Failing the intake valves closed is preferable to allowing them to remain open and potentially allowing radiation or chlorine into the Control P.oom. i For an optimum design, the chlorine de'.ectors for each intake should be powered by separate power supplies. This would add reliabilita by preventing both intakes from closing on total loss of non-safety power.
In summary, the present design meets separation criteria and provides for proper failure of the safety valves on loss of non-safety power. However, the control circuit could have been
\ optimized by powering the chlorine detectors from separate power supplies. This is not considered a violation of the single failure criteria, and root cause is not an issue.
- 2. Scope & results of the investigati_on performed to determine the extent of the finding:
Procedures are in place at McGuire to reopen the VC air intake valves. These procedures were followed on October 12, 1989 (see
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'.J. ? 369/89-31), and the valves were reopened. This LER was written as c, rer it of a blown fuse in the chlorine detector circuit which causeG the intake valves to close. Station personnel feel that thesu procedures are adequate to address this issue. (Reference PIR 0-M89-0270.)
- 3. Corrective steps which have been taken and the results achieved:
As a result of LER 369/89-31, Station Problem Report (SPR) No. 2989 was written by station personnel to separately fuse each chlorine monitor. Implementation of this SPR will prevent a reoccurrence of the proble.n identified in the LER; however, the following additional changes should be made for increased reliability:
a, Power the chlorine detectors associated with each intake from separate non-safety power supplies.
- b. Revise control circuitry to allow the bypass of the radiation monitors and chlorine detectors during maintenance.
At the tie.e of this evaluation, no further corrective actions were deemed necessary.
In January.of 1991, Operations (OPS) personnel began an evaluation of the compensatory actions requ' ired by OPS personnel in emergency situations. A concern had been raised because of the number of actions required. As a result, OPS petsonnel generated 4 memorandum to Project Services and DE personnel requesting a reevaluation of the need for a procedure response requiring OPS personnel to reopen the VC system air int ske valves.
' Consequently, a meeting was held between OPS, Project Services, DE, and Mechanical Maintenance personnel to discuss the problem. Personnel involved decided to ask for a further thange to be made to NSM MG-52065 deleting some of the automatic closure signals from the chlorine detectors and radiation monitors. This would simplify the compensatory actions required by OPS personnel.
On February 18, 1991, DE personnel began a review of NSM MG-52065. The ,
purpose of-the review was to examine the' proposed recommendations for change from a safety standpoint. As a result, the fact that loss of non-essential power to the chlorine detectors or to the radiation monitors (EMF-43A and 43B) the VC system outside air in'.ake isolation valves will close and cannot be reopened from the Control Room was evaluated. This was different than the evaluation performed af ter the finding by SITA Audit 89-02. The previous evaluation had not considered the effect of loss of power to the radiation monitors. Also,-an evaluation of allowahle time for not having the Control Room pressurized had been performed later and had identified only a 20 to 30 second response time for compensatory actions. At this time, it was determined that the compensatory action requiring OPS personnel to open the breaker for each valve and to manually open each valve, may not be achieved
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On February 19, 1991, DE personnel and OPS personnel determined the VC system might be inoperable and initiated PIR 0+M91-0033 to resolve the problem.
Consequently, at 2140, on February 19, both trains of the VC system were declared inoperable and TS Action Statement 3.0.3 was entered for both units.
Temporary modifications were initiated to remove the automatic action on loss of power irom the chlorine detectors and radiation monitors. Also, changes to the procedures for responses to high chlorine or radiation alarms were initiated.
At 0245 on February 20,.1991, the modifications were completed and appropriate procedure changes were implemented to have OPS personnel close the valves upon a high radiation or high chlorine alarm. Therefore, both traina of the VC system were declared operable and TS Action Statement 3.0.3 was exited for both units.
Conclusion This event is assigned a cause of Design Oversight. At the time the chlorine and radiation monitor circuitry was designed, a failure mode on loss of power was selected in what was considered the most conservative direction. Failing the VC intake valves closed was preferable to allowing them to remain open and potentially allow radiation or chlorine into the Control Room. Although this presents a problem because outside air would not be available N '
pressurizing the Control Room, the intent at the time was considered to be conservative based on available technical information.
A contributing cause of Management Deficiency is assigned because when the SITA Audit detected the problem with the design, the corrective wetions taken were not generic enough in nature to resolve the problem. SPR 2989 was written and approved to seperately fuse each chlorine detector.
Recommendations were also made to power the chlorine. detectors associated with each intake form seperate non-essential power supplies and to revise the control circuitry to allow the bypass of the chlorine detectors and radiation monitors during maintenance. At the time Management personnel involved felt that the procedures in place, requiring ops personnel to reopen the intake
. valves on loss of power, and these proposed modifications were adequate to resolve the problem. This evaluation had not considered the ef fect of loss of power to the radiation monitors nor the evaluation performed later establishing a short 20 to 30 second response time to take compensatory
- i action and open the intake valves. Therefore, no further investigation or l
corrective actions were deemed necessary. However, upon a second evaluation l
which included consideration of the allowabe time for not having the Control Room pressurized, DE personnel determined that the compensatory actions in place may not be achieved within the time requirements of the assumptions for the Control Room dose analysis.
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0l 0 l6 of l7 ein,, . w nac w .nm When the deficiencies were discovered, appropriate actions were taken to delete the automatic isolation function from both the chlorine detectors and radiation monitor 2. Also, appropriate procedure changes were made to ensure that,the appropriate intake valves would be closed upon receipt of a high radiation or high chlorine alarm signal. All appropriate notifications were made when the units entered TS Action Statement 3.0.3. During the time when the VC system was inoperable, OPS Control Room personnel were fully aware of the situation and no events occurred requiring them to take further action.
A review of the Operating Experience Program data base for the previous 24 months prior to this event revealed 3 LERs documenting Design Deficiencies
- with the VC system because of a design oversight. Ther.e were LERs 369/89-15, 369/90-10, and 369/89-31. LER 369/89-15 documented a design oversight with respect to the proper reference point for measuring Control Room pressure.
LER 369/90-10-0 documented an unanticipated interaction of systems when the VC system heaters would not operate as designed. LER 369/89-31 documented a design oversight with respect to a similar problem as this LER and the corrective actions taken were not of generic enough nature to prevent this event from occur:ing as determined by further analysis. Therefore, the problem is considered to be recurring.
This event is not Nuclesr Plant Reliability Data System (NPRDS) reportable.
There were no personnel injuries, radiation overexposures, or releases of radioactive material as a result of this event.
CORRECTIVE ACTIONS:
Immediate: 1) Temporary Modifications 6010 and 6011, removing the automatic closure function from the chlorine detectors and radiation monitors were installed as directed by work request 890295.
- 2) Changes were made to procedures OP/2/A/6100/10N, Annunciator Response For Panel 2AD13, OP/1/A/6100/10R, Annunciator Response for Panel IRAD2, and OP/1/A/6100/10Q, Annunciator Response For Panel IRAD1 specifying required actions for different accident scenarios.
l Subsequent: 1) Procedure EP/1/A/5000/01, Safety injection or Reactor Trip, was changed to specify required actions for different accident scenarios.
Planned: 1) DE and Project Services personnel will evaluate and make permanent changes to the circuits for the l chlorine detectors and radiation monitors involved. l l
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- 2) The previously installed temporary modifications 6010 and 6011 will be removed as directed by work request 890295.
SAFETY ANALYSIS:
The design requirements of the VC system are to supply filtered air at a controlled temperature and humidity to the Control Room and to pressurize the Control Room to prevent inleakage of untiltered air. The VC system helps ensure that doses to Control Room personnel are As Low As Reasonably Achievable and in the event of a ciesign basis accident, the VC system acts to limit Control Room operator dose 0 less than the General Design Criterion 19 limits, i.e., less than 5 Rem whole body or its equivalent. Since whole body doses are primarily due to exposure to noble gases which the filters do not remove, the VC system is not required to ensure acceptable whole body doses.
However, the VC system redures thyroid and skin doses by pressurizing the Control Room with filtered air to minimize unfiltered in-leakage.
The principle contaminant contained in air leaking into the Control Room is assumed to be radioactive Iodine which is very conservatively modeled in dose calculations. Very low amounts of Iodine would be expected to reach the area around the Control Room since this requires passage through either Auxiliary (VA) (eIIS:VF3 or Turbine Building Ventilation systems l't.IIS:VK] or passageways first.
- No credit is taken for the VA filtration, with regard to Control Room dose ,
calculation, in. mitigating the Emergency Core Cooling System leakage source.
However, this system is automatically switched to the filtered exhaust mode of operation on an accident or Blackout signal or if radiation is detected by the exhaust monitor [ Ells: MON). The VA system has four 50 percent capacity trains for Units 7 and 2 which respond to an accident on either unit thus providing essenti G y redundant protection. Operation of the VA system in the filtered exhaust mode by either train of the system would serve to reduce the calculated dose to Control Room personnel.
In the event the Control Room atmosphere became unbreathable, self contained breathing apparatus (SCBAs) provided in the Control Room area could be employed. . Radiation monitors in the Control Room would alert Control Room personnel of high radiation levels.
Both trains of the VC system were technically inoperable but were fully capable of operating.
During the event, there were no accidents that would have required operation of the VC system to maintain habitability of the Control Room.
This event did not affect the health and safety of the public.
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