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Category:LICENSEE EVENT REPORT (SEE ALSO AO
MONTHYEARML20046C2121993-07-30030 July 1993 LER 93-004-01:on 930301,confirmed That Channel D Axial Shape Index (Asi) Being Calculated in Reverse Since 921031-930301 Due to Drawing Discrepancies Associated W/Control Channel B. Temporary Mod 92-078 & Standing Order 0-25 Revised ML20046A8691993-07-26026 July 1993 LER 93-011-00:on 930624,experienced Reactor Trip Due to Loss of Load.Caused by Lack of Proper Job Planning,Lack of Formal Decision Making Process & Incomplete Communications.Training Will Be Provided to Operations personnel.W/930726 Ltr ML20045H2561993-07-12012 July 1993 LER 93-010-00:on 930611,1 of 14 Halon Cylinders Did Not Meet Min Pressure Acceptance Criteria Listed in Semiannual Switchgear Rooms Surveillance Test.Caused by Failure of Test to Include Necessary Steps.Cylinder recharged.W/930712 Ltr ML20045D7201993-06-22022 June 1993 LER 93-009-00:on 930524,apparent Spurious Signal from Pressurizer Level Instrumentation Caused Backup Charging Pumps to Automatically Start,Due to Deterioration of Wiring. Instrument Loop Calibration Will Be performed.W/930622 Ltr ML20045D3741993-06-21021 June 1993 LER 93-008-00:on 930520,determined That TS SR Not Satisfied for Stack Flow Indicator,Per Amend 137 Issued on 910307. Caused by Lack of Attention to Detail.Calibr & Functional Test Procedures developed.W/930621 Ltr ML20044H5261993-06-0101 June 1993 LER 93-007-00:on 930430,unplanned Emergency Generator Start & Rt Signal Occurred.Caused by Inadequate Attention to Detail,Labeling of Fuse Drawers,Caution Signs & Training. Labeling & Caution Signs upgraded.W/930601 Ltr ML20044G4941993-05-26026 May 1993 LER 93-006-00:on 930118,Halon Fire Suppression Sys for Switchgear Rooms Disabled to Allow Repair/Replacement of Halon Sys Piping.On 930427,individual Responsible for Fire Watch Not Present.Individual Relieved of Responsibilities ML20044B6711993-02-22022 February 1993 LER 93-002-00:on 930122,determined That Current SG LP Signal Block Reset Values Greater than Allowed Ts.Caused by Improper Design.Test Procedures Will Be Revised by 930917 to Specify Desired Value for Block function.W/930222 Ltr ML20024G6821991-04-19019 April 1991 LER 91-007-00:on 910320,480 Volt Circuit Breaker Coordination Outside Design Basis.Caused by Deficiencies in Original Sys Design.Breaker/Fuse Coordination Study to Be Completed & Problems Will Be corrected.W/910419 Ltr ML20029C1591991-03-21021 March 1991 LER 91-004-00:on 910212,offsite Power Low Signal Outside Design Basis.Caused by Inadequate Mod Design at Time of Performance of Original Degraded Voltage Analysis. Engineering Analysis EA-FC-91-017 performed.W/910321 Ltr ML20029C1051991-03-18018 March 1991 LER 91-002-00:on 901209,ventilation Isolation Actuation Signal Generated by High Alarm on Process Radiation Monitor RM-062.Caused by Accumulation of Noncondensible Gases in Sample Piping.Valve Packing Leak repaired.W/910318 Ltr ML20029A2981991-02-0808 February 1991 LER 91-001-00:on 910109,determined That Containment Tendon Surveillances Performed in 1981 & 1985 Did Not Reflect Guidance in Tech Specs.Caused by Inadequate Administrative Controls.Testing Program Plan implemented.W/910208 Ltr ML20029A2971991-02-0606 February 1991 LER 90-022-02:on 900907,approx 460 Fire Barrier Penetration seals,60 Fire Dampers & 6 Fire Doors Declared Nonfunctional Per NRC Info Notice 88-004 Due to Lack of Documentation. Plant Outage Required to Implement Repairs/Replacements ML20028G9171990-09-28028 September 1990 LER 90-021-00:on 900829,inadvertent Reactor Protective Sys Actuation Occurred While Operator Changed Power Source. Caused by Operator Not Following Proper Procedures.Operator counseled.W/900928 Ltr ML20044B0131990-07-12012 July 1990 LER 90-018-00:on 900612,reactor Protective Sys (RPS) Trip Units for Axial Power Distribution Determined to Be Inoperable.Caused by Procedural Deficiencies.Procedure Revised & RPS Surveillance Tests reviewed.W/900712 Ltr ML20043F6301990-06-11011 June 1990 LER 90-016-00:on 900511,accident Scenarios Identified by Which Auxiliary Feedwater Piping from Discharge of Turbine Driven Auxiliary Feedwater Pump FW-10 Can Be Overpressurized.Caused by Design deficiency.W/900611 Ltr ML20043F2441990-06-0707 June 1990 LER 90-015-00:on 900507,PORV Variable Setpoints Used for Low Pressure Overpressure Protection Determined to Be Nonconservative for PORV Opening Time.Caused by Design Deficiency.Tech Spec Amend prepared.W/900607 Ltr ML20043C0991990-05-29029 May 1990 LER 90-014-00:on 900427,investigation Revealed That Component Cooling Water Piping to Reactor Coolant Pump Seal Coolers Could Be Targets of High Energy Line Break.Safety Analysis for Operability completed.W/900529 Ltr ML20042G7211990-05-10010 May 1990 LER 90-011-00:on 900402,inadvertent Actuation of Pressurizer Pressure Low Signal Occurred While Performing Calibr Procedure.Caused by Inappropriate Action by Technician Involved.Validation of Procedures reviewed.W/900510 Ltr ML20042E6871990-04-23023 April 1990 LER 90-007-01:on 900228,determined That Several Supports Would Be Overloaded During Seismic Event on Nonsafety Related & safety-related Main Steam Piping.Caused by Design Deficiency.Piping Supports modified.W/900423 Ltr ML20042E6861990-04-23023 April 1990 LER 90-009-00:on 900316,potential Overpressurization of Auxiliary Feedwater Piping Could Have Occurred During Thermal Expansion of Process Fluid Between Closed Valved. Caused by Design deficiencies.W/900423 Ltr ML20012E7641990-03-26026 March 1990 LER 90-005-00:on 900223,determined That Spent Fuel Pool Area Charcoal Filtration Unit VA-66 Was Outside Design Basis. Caused by Insufficient Airflow Into Unit.Affected Updated SAR Analysis Will Be updated.W/900326 Ltr ML20012D0121990-03-19019 March 1990 LER 90-004-00:on 900217,lift Pressures for 6 of 10 Main Steam Safety Valves Found Outside Acceptance Criteria. Caused by Overly Restrictive Operability Criteria.Valves Recalibr & License Amend Submitted to NRC.W/900319 Ltr ML20012D0101990-03-19019 March 1990 LER 90-003-00:on 900216,determined That Auxiliary Feedwater Piping Outside Normal Stress Limits of ASME Code & Design Basis Specified in Updated Sar.Caused by Design Deficiency.Valve Operators Will Be inspected.W/900319 Ltr ML20012B6361990-03-0909 March 1990 LER 89-017-01:on 890624,internal Valve Component from Check Valve Found Lying on Pump Discharge Vane.Repair or Replacement of Valve Internals Could Not Be Accomplished within Time Requirement of Tech Spec.W/900309 Ltr ML20006E1041990-02-0909 February 1990 LER 90-001-00:on 900108,fire Barrier for Wall Between Auxiliary Bldg Rooms 26 & 34 Breached But Hourly Fire Watch Patrol Not Established.Caused by Lack of Sufficient Training for Shift Supervisors.Standing Order revised.W/900209 Ltr ML20011E2691990-02-0505 February 1990 LER 89-024-00:on 891221,determined That Containment Spray Pumps & Suction Header Piping Not Constructed for Use as Backup to LPSI Sys for Shutdown Cooling.Caused by Inadequate Review of Assumptions.Firewatch established.W/900205 Ltr ML20011E2271990-02-0101 February 1990 LER 89-021-00:on 891010,util Informed by C-E of Potential Nonconservative Setpoint in Reactor Protection Sys Thermal Margin/Low Pressure Trip Unit.Caused by Error in Incorporating Transient Setpoint analyses.W/900201 Ltr ML20005F7151990-01-10010 January 1990 LER 89-023-00:on 891211,hourly Firewatch Patrol Entered Posted High Radiation Area W/O Meeting Entry Requirements for Area.Briefings on High Radiation Entry Requirements Held for Personnel W/Assigned dosimetry.W/900110 Ltr ML19354D6381989-12-20020 December 1989 LER 89-022-00:on 890805,change to Surveillance Procedure ST-CEA-1 Became Effective Which Would Have Made Both Emergency Diesel Generators Simultaneously Inoperable During Portion of Test.Change removed.W/891220 Ltr ML19332E7431989-12-0808 December 1989 LER 88-037-01:on 881214,one of Two Supply Headers Supplying Fire Suppression Headers in Auxiliary Bldg Isolated.Caused by Lack of Procedural Guidance & Inadequate Procedural Controls.Standing Order G-58 Will Be revised.W/891208 Ltr ML19332E2681989-12-0101 December 1989 LER 89-016-02:on 890616,for Unknown Period Since 890614, Auxiliary Feedwater Pump FW-10 Operated Outside Design Basis for Certain Accident Conditions.Caused by Inoperable Speed Control Loop.Action Plan implemented.W/891201 Ltr ML19351A4541989-11-22022 November 1989 LER 89-020-00:on 891012,determined That Two of Four Component Cooling Water HXs Simultaneously Inoperable for More than 24 H.Caused by Inadequate Controls Re Return of Equipment to Svc.Standing Order revised.W/891122 Ltr ML19327B5481989-10-24024 October 1989 LER 89-019-00:on 890924,indication of High Temp for Reactor Coolant Pump RC-3A Upper Motor Thrust Bearing Received in Control Room.Caused by Damaged Cable for Bearing Resistive Temp Device.Damaged Cable replaced.W/891024 Ltr ML19325D2471989-10-13013 October 1989 LER 89-012-01:on 890502,main Feedwater Isolation Valve to Steam Generator a Found Inoperable Due to Improperly Set Torque Switch.Caused by Inadequate Program for Maint of Motor Operated Valves.Torque Switches reset.W/891013 Ltr ML20028C7711983-01-0606 January 1983 LER 82-020/03L-0:on 821207,during Main Steam Safety Valve Test,Four Main Steam Safety Valves Had Lift Setpoints Out of Tolerance.Caused by Normal Drift of Valves Over Operating Cycle.Valves Readjusted ML20028B5451982-10-28028 October 1982 LER 82-019/03L-0:on 821024,MSIVs HCV-1041A & HCV-1042A Stopped Three to Four Degrees Off Seat When Signaled to Close.Caused by Binding Between Valve Packing & Shaft. Packings Sprayed W/Penetrant Oil ML20052J0631982-04-27027 April 1982 LER 82-009/03L-0:on 820411,while Exchanging Component Cooling Water Heat Exchangers,Associated Outlet Valves HCV-490B,HCV-491B & HCV-492B Failed to Open.Cause Not stated.HCV-491B Reassembled & Tested ML20052B2361982-04-0707 April 1982 LER 82-006/03L-0:on 820323,during Surveillance Test ST-ISI- WD-1,F.1,valve HCV-506A Failed to Close Via Control Room Switch.Caused by Solenoid Valve Malfunction.Solenoid Valve Disassembled,Cleaned & Reassembled ML20052D9291982-04-0606 April 1982 LER 82-008/03L-0:on 820330,during Performance of ST-FW-1, F.2(b)(6)per Tech Spec 3.9,steam Driven Auxiliary Feedwater Pump Failed to Start.Caused by Back Pressure Trip Lever in Tripped Position.Lever Reset ML20041G1291982-02-22022 February 1982 LER 82-005/03L-0:on 820210,at 98% Power,Control Element 24 Inserted Into Core.Emergency Procedure EP-13,CEDM Malfunctions,Implemented & Power Stabilized at 88%.Caused by Erroneous Operating Instruction.Instruction Changed ML20041F7481982-02-17017 February 1982 LER 82-003/03L-0:on 820203,containment Isolation Valve Associated W/Gas Vent Header HCV-507A Failed to Close on Demand.Caused by Solenoid Valve Plunger Sticking in Energized Position.Plunger Freed ML20041F6251982-02-0505 February 1982 LER 82-004/03L-0:on 820203,small Quantity of Radioactive Gas/Particulate Released to Auxiliary Bldg During Routine Operation.Caused by Failure of Stack Gas Monitor RM-062 to Alarm at Appropriate Setpoint Due to Faulty Alarm Module ML20041B1051982-01-28028 January 1982 LER 82-002/03L-0:on 820114,at 99% Power,Lockout Relay 86B1, Containment Radiation High Signal,Failed to Actuate on Demand by Plant Radiation Monitoring Sys.Caused by Burnt Coil on Lockout Relay.Coil Replaced & Tested Satisfactorily ML20041B1171982-01-19019 January 1982 LER 82-001/03L-0:on 820111,during Normal Operation,Two Fire Barrier Penetrations Found Nonfunctional.Shift Supervisor Immediately Notified;However,Fire Watch Not Posted.Insp & Supervisor Personnel Instructed on Proper Actions ML20039B4561981-12-11011 December 1981 LER 81-011/03L-0:on 811113,containment Isolation Valves Opened & Ventilation Process Initiated W/Containment Air Monitor RM-050/051 Inoperable.Caused by Personnel Error. Valves Closed ML20010H8581981-08-27027 August 1981 LER 81-008/03L-0:on 810813,86B/CRHS (Containment Radiation High Signal) Lockout Relay Failed to Actuate When RM-062 Was Placed in Alarm,Resulting in Failure of 86B1/CRHS Relay to Actuate.Caused by Dirt in Relay Latching Mechanism ML20041F6291981-08-27027 August 1981 LER 81-008/03L-1:on 810813,containment Radiation High Signal 86B Lockout Relay Failed to Actuate When Radiation Monitor RM-062 Placed in Alarm.Caused by Bound Relay Latching Mechanism Due to Dirt & Grease.Latch Cleaned ML20010C2271981-07-0707 July 1981 LER 81-006/03L-0:on 810624,reactor Protection Sys Nuclear Power Recorder Channel B Trip Setpoints Determined to Be Nonconservative.Caused by Faulty Temp Change Power Calculation Due to Grounded Hot Leg Temp Loop ML20004B1111981-05-0606 May 1981 LER 81-005/03L-0:on 810423,dc Sequencer Timers AC-3A (Component Cooling Water Pump) & AC-102A (Raw Water Pump) Failed to Time Out within Prescribed Limit.Cause Unknown Mechanisms Satisfactorily Inspected 1993-07-30
[Table view] Category:RO)
MONTHYEARML20046C2121993-07-30030 July 1993 LER 93-004-01:on 930301,confirmed That Channel D Axial Shape Index (Asi) Being Calculated in Reverse Since 921031-930301 Due to Drawing Discrepancies Associated W/Control Channel B. Temporary Mod 92-078 & Standing Order 0-25 Revised ML20046A8691993-07-26026 July 1993 LER 93-011-00:on 930624,experienced Reactor Trip Due to Loss of Load.Caused by Lack of Proper Job Planning,Lack of Formal Decision Making Process & Incomplete Communications.Training Will Be Provided to Operations personnel.W/930726 Ltr ML20045H2561993-07-12012 July 1993 LER 93-010-00:on 930611,1 of 14 Halon Cylinders Did Not Meet Min Pressure Acceptance Criteria Listed in Semiannual Switchgear Rooms Surveillance Test.Caused by Failure of Test to Include Necessary Steps.Cylinder recharged.W/930712 Ltr ML20045D7201993-06-22022 June 1993 LER 93-009-00:on 930524,apparent Spurious Signal from Pressurizer Level Instrumentation Caused Backup Charging Pumps to Automatically Start,Due to Deterioration of Wiring. Instrument Loop Calibration Will Be performed.W/930622 Ltr ML20045D3741993-06-21021 June 1993 LER 93-008-00:on 930520,determined That TS SR Not Satisfied for Stack Flow Indicator,Per Amend 137 Issued on 910307. Caused by Lack of Attention to Detail.Calibr & Functional Test Procedures developed.W/930621 Ltr ML20044H5261993-06-0101 June 1993 LER 93-007-00:on 930430,unplanned Emergency Generator Start & Rt Signal Occurred.Caused by Inadequate Attention to Detail,Labeling of Fuse Drawers,Caution Signs & Training. Labeling & Caution Signs upgraded.W/930601 Ltr ML20044G4941993-05-26026 May 1993 LER 93-006-00:on 930118,Halon Fire Suppression Sys for Switchgear Rooms Disabled to Allow Repair/Replacement of Halon Sys Piping.On 930427,individual Responsible for Fire Watch Not Present.Individual Relieved of Responsibilities ML20044B6711993-02-22022 February 1993 LER 93-002-00:on 930122,determined That Current SG LP Signal Block Reset Values Greater than Allowed Ts.Caused by Improper Design.Test Procedures Will Be Revised by 930917 to Specify Desired Value for Block function.W/930222 Ltr ML20024G6821991-04-19019 April 1991 LER 91-007-00:on 910320,480 Volt Circuit Breaker Coordination Outside Design Basis.Caused by Deficiencies in Original Sys Design.Breaker/Fuse Coordination Study to Be Completed & Problems Will Be corrected.W/910419 Ltr ML20029C1591991-03-21021 March 1991 LER 91-004-00:on 910212,offsite Power Low Signal Outside Design Basis.Caused by Inadequate Mod Design at Time of Performance of Original Degraded Voltage Analysis. Engineering Analysis EA-FC-91-017 performed.W/910321 Ltr ML20029C1051991-03-18018 March 1991 LER 91-002-00:on 901209,ventilation Isolation Actuation Signal Generated by High Alarm on Process Radiation Monitor RM-062.Caused by Accumulation of Noncondensible Gases in Sample Piping.Valve Packing Leak repaired.W/910318 Ltr ML20029A2981991-02-0808 February 1991 LER 91-001-00:on 910109,determined That Containment Tendon Surveillances Performed in 1981 & 1985 Did Not Reflect Guidance in Tech Specs.Caused by Inadequate Administrative Controls.Testing Program Plan implemented.W/910208 Ltr ML20029A2971991-02-0606 February 1991 LER 90-022-02:on 900907,approx 460 Fire Barrier Penetration seals,60 Fire Dampers & 6 Fire Doors Declared Nonfunctional Per NRC Info Notice 88-004 Due to Lack of Documentation. Plant Outage Required to Implement Repairs/Replacements ML20028G9171990-09-28028 September 1990 LER 90-021-00:on 900829,inadvertent Reactor Protective Sys Actuation Occurred While Operator Changed Power Source. Caused by Operator Not Following Proper Procedures.Operator counseled.W/900928 Ltr ML20044B0131990-07-12012 July 1990 LER 90-018-00:on 900612,reactor Protective Sys (RPS) Trip Units for Axial Power Distribution Determined to Be Inoperable.Caused by Procedural Deficiencies.Procedure Revised & RPS Surveillance Tests reviewed.W/900712 Ltr ML20043F6301990-06-11011 June 1990 LER 90-016-00:on 900511,accident Scenarios Identified by Which Auxiliary Feedwater Piping from Discharge of Turbine Driven Auxiliary Feedwater Pump FW-10 Can Be Overpressurized.Caused by Design deficiency.W/900611 Ltr ML20043F2441990-06-0707 June 1990 LER 90-015-00:on 900507,PORV Variable Setpoints Used for Low Pressure Overpressure Protection Determined to Be Nonconservative for PORV Opening Time.Caused by Design Deficiency.Tech Spec Amend prepared.W/900607 Ltr ML20043C0991990-05-29029 May 1990 LER 90-014-00:on 900427,investigation Revealed That Component Cooling Water Piping to Reactor Coolant Pump Seal Coolers Could Be Targets of High Energy Line Break.Safety Analysis for Operability completed.W/900529 Ltr ML20042G7211990-05-10010 May 1990 LER 90-011-00:on 900402,inadvertent Actuation of Pressurizer Pressure Low Signal Occurred While Performing Calibr Procedure.Caused by Inappropriate Action by Technician Involved.Validation of Procedures reviewed.W/900510 Ltr ML20042E6871990-04-23023 April 1990 LER 90-007-01:on 900228,determined That Several Supports Would Be Overloaded During Seismic Event on Nonsafety Related & safety-related Main Steam Piping.Caused by Design Deficiency.Piping Supports modified.W/900423 Ltr ML20042E6861990-04-23023 April 1990 LER 90-009-00:on 900316,potential Overpressurization of Auxiliary Feedwater Piping Could Have Occurred During Thermal Expansion of Process Fluid Between Closed Valved. Caused by Design deficiencies.W/900423 Ltr ML20012E7641990-03-26026 March 1990 LER 90-005-00:on 900223,determined That Spent Fuel Pool Area Charcoal Filtration Unit VA-66 Was Outside Design Basis. Caused by Insufficient Airflow Into Unit.Affected Updated SAR Analysis Will Be updated.W/900326 Ltr ML20012D0121990-03-19019 March 1990 LER 90-004-00:on 900217,lift Pressures for 6 of 10 Main Steam Safety Valves Found Outside Acceptance Criteria. Caused by Overly Restrictive Operability Criteria.Valves Recalibr & License Amend Submitted to NRC.W/900319 Ltr ML20012D0101990-03-19019 March 1990 LER 90-003-00:on 900216,determined That Auxiliary Feedwater Piping Outside Normal Stress Limits of ASME Code & Design Basis Specified in Updated Sar.Caused by Design Deficiency.Valve Operators Will Be inspected.W/900319 Ltr ML20012B6361990-03-0909 March 1990 LER 89-017-01:on 890624,internal Valve Component from Check Valve Found Lying on Pump Discharge Vane.Repair or Replacement of Valve Internals Could Not Be Accomplished within Time Requirement of Tech Spec.W/900309 Ltr ML20006E1041990-02-0909 February 1990 LER 90-001-00:on 900108,fire Barrier for Wall Between Auxiliary Bldg Rooms 26 & 34 Breached But Hourly Fire Watch Patrol Not Established.Caused by Lack of Sufficient Training for Shift Supervisors.Standing Order revised.W/900209 Ltr ML20011E2691990-02-0505 February 1990 LER 89-024-00:on 891221,determined That Containment Spray Pumps & Suction Header Piping Not Constructed for Use as Backup to LPSI Sys for Shutdown Cooling.Caused by Inadequate Review of Assumptions.Firewatch established.W/900205 Ltr ML20011E2271990-02-0101 February 1990 LER 89-021-00:on 891010,util Informed by C-E of Potential Nonconservative Setpoint in Reactor Protection Sys Thermal Margin/Low Pressure Trip Unit.Caused by Error in Incorporating Transient Setpoint analyses.W/900201 Ltr ML20005F7151990-01-10010 January 1990 LER 89-023-00:on 891211,hourly Firewatch Patrol Entered Posted High Radiation Area W/O Meeting Entry Requirements for Area.Briefings on High Radiation Entry Requirements Held for Personnel W/Assigned dosimetry.W/900110 Ltr ML19354D6381989-12-20020 December 1989 LER 89-022-00:on 890805,change to Surveillance Procedure ST-CEA-1 Became Effective Which Would Have Made Both Emergency Diesel Generators Simultaneously Inoperable During Portion of Test.Change removed.W/891220 Ltr ML19332E7431989-12-0808 December 1989 LER 88-037-01:on 881214,one of Two Supply Headers Supplying Fire Suppression Headers in Auxiliary Bldg Isolated.Caused by Lack of Procedural Guidance & Inadequate Procedural Controls.Standing Order G-58 Will Be revised.W/891208 Ltr ML19332E2681989-12-0101 December 1989 LER 89-016-02:on 890616,for Unknown Period Since 890614, Auxiliary Feedwater Pump FW-10 Operated Outside Design Basis for Certain Accident Conditions.Caused by Inoperable Speed Control Loop.Action Plan implemented.W/891201 Ltr ML19351A4541989-11-22022 November 1989 LER 89-020-00:on 891012,determined That Two of Four Component Cooling Water HXs Simultaneously Inoperable for More than 24 H.Caused by Inadequate Controls Re Return of Equipment to Svc.Standing Order revised.W/891122 Ltr ML19327B5481989-10-24024 October 1989 LER 89-019-00:on 890924,indication of High Temp for Reactor Coolant Pump RC-3A Upper Motor Thrust Bearing Received in Control Room.Caused by Damaged Cable for Bearing Resistive Temp Device.Damaged Cable replaced.W/891024 Ltr ML19325D2471989-10-13013 October 1989 LER 89-012-01:on 890502,main Feedwater Isolation Valve to Steam Generator a Found Inoperable Due to Improperly Set Torque Switch.Caused by Inadequate Program for Maint of Motor Operated Valves.Torque Switches reset.W/891013 Ltr ML20028C7711983-01-0606 January 1983 LER 82-020/03L-0:on 821207,during Main Steam Safety Valve Test,Four Main Steam Safety Valves Had Lift Setpoints Out of Tolerance.Caused by Normal Drift of Valves Over Operating Cycle.Valves Readjusted ML20028B5451982-10-28028 October 1982 LER 82-019/03L-0:on 821024,MSIVs HCV-1041A & HCV-1042A Stopped Three to Four Degrees Off Seat When Signaled to Close.Caused by Binding Between Valve Packing & Shaft. Packings Sprayed W/Penetrant Oil ML20052J0631982-04-27027 April 1982 LER 82-009/03L-0:on 820411,while Exchanging Component Cooling Water Heat Exchangers,Associated Outlet Valves HCV-490B,HCV-491B & HCV-492B Failed to Open.Cause Not stated.HCV-491B Reassembled & Tested ML20052B2361982-04-0707 April 1982 LER 82-006/03L-0:on 820323,during Surveillance Test ST-ISI- WD-1,F.1,valve HCV-506A Failed to Close Via Control Room Switch.Caused by Solenoid Valve Malfunction.Solenoid Valve Disassembled,Cleaned & Reassembled ML20052D9291982-04-0606 April 1982 LER 82-008/03L-0:on 820330,during Performance of ST-FW-1, F.2(b)(6)per Tech Spec 3.9,steam Driven Auxiliary Feedwater Pump Failed to Start.Caused by Back Pressure Trip Lever in Tripped Position.Lever Reset ML20041G1291982-02-22022 February 1982 LER 82-005/03L-0:on 820210,at 98% Power,Control Element 24 Inserted Into Core.Emergency Procedure EP-13,CEDM Malfunctions,Implemented & Power Stabilized at 88%.Caused by Erroneous Operating Instruction.Instruction Changed ML20041F7481982-02-17017 February 1982 LER 82-003/03L-0:on 820203,containment Isolation Valve Associated W/Gas Vent Header HCV-507A Failed to Close on Demand.Caused by Solenoid Valve Plunger Sticking in Energized Position.Plunger Freed ML20041F6251982-02-0505 February 1982 LER 82-004/03L-0:on 820203,small Quantity of Radioactive Gas/Particulate Released to Auxiliary Bldg During Routine Operation.Caused by Failure of Stack Gas Monitor RM-062 to Alarm at Appropriate Setpoint Due to Faulty Alarm Module ML20041B1051982-01-28028 January 1982 LER 82-002/03L-0:on 820114,at 99% Power,Lockout Relay 86B1, Containment Radiation High Signal,Failed to Actuate on Demand by Plant Radiation Monitoring Sys.Caused by Burnt Coil on Lockout Relay.Coil Replaced & Tested Satisfactorily ML20041B1171982-01-19019 January 1982 LER 82-001/03L-0:on 820111,during Normal Operation,Two Fire Barrier Penetrations Found Nonfunctional.Shift Supervisor Immediately Notified;However,Fire Watch Not Posted.Insp & Supervisor Personnel Instructed on Proper Actions ML20039B4561981-12-11011 December 1981 LER 81-011/03L-0:on 811113,containment Isolation Valves Opened & Ventilation Process Initiated W/Containment Air Monitor RM-050/051 Inoperable.Caused by Personnel Error. Valves Closed ML20010H8581981-08-27027 August 1981 LER 81-008/03L-0:on 810813,86B/CRHS (Containment Radiation High Signal) Lockout Relay Failed to Actuate When RM-062 Was Placed in Alarm,Resulting in Failure of 86B1/CRHS Relay to Actuate.Caused by Dirt in Relay Latching Mechanism ML20041F6291981-08-27027 August 1981 LER 81-008/03L-1:on 810813,containment Radiation High Signal 86B Lockout Relay Failed to Actuate When Radiation Monitor RM-062 Placed in Alarm.Caused by Bound Relay Latching Mechanism Due to Dirt & Grease.Latch Cleaned ML20010C2271981-07-0707 July 1981 LER 81-006/03L-0:on 810624,reactor Protection Sys Nuclear Power Recorder Channel B Trip Setpoints Determined to Be Nonconservative.Caused by Faulty Temp Change Power Calculation Due to Grounded Hot Leg Temp Loop ML20004B1111981-05-0606 May 1981 LER 81-005/03L-0:on 810423,dc Sequencer Timers AC-3A (Component Cooling Water Pump) & AC-102A (Raw Water Pump) Failed to Time Out within Prescribed Limit.Cause Unknown Mechanisms Satisfactorily Inspected 1993-07-30
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217B5401999-10-0606 October 1999 Safety Evaluation Supporting Amend 193 to License DPR-40 ML20217A9931999-09-30030 September 1999 NRC Regulatory Assessment & Oversight Pilot Program, Performance Indicator Data LIC-99-0096, Monthly Operating Rept for Sept 1999 for Fcs,Unit 1.With1999-09-30030 September 1999 Monthly Operating Rept for Sept 1999 for Fcs,Unit 1.With ML20211J9321999-09-0202 September 1999 Safety Evaluation Concluding That Licensee Proposed Alternatives Provide Acceptable Level of Quality & Safety. Proposed Alternatives Authorized for Remainder of Third ten- Yr ISI Interval for Fort Calhoun Station,Unit 1 LIC-99-0084, Monthly Operating Rept for Aug 1999 for Fort Calhoun Station.With1999-08-31031 August 1999 Monthly Operating Rept for Aug 1999 for Fort Calhoun Station.With ML20216E6431999-08-26026 August 1999 Rev 19 to TDB-VI, COLR for FCS Unit 1 ML20210R1961999-07-31031 July 1999 Monthly Operating Rept for July 1999 for Fcs,Unit 1 ML20210G2181999-07-27027 July 1999 Safety Evaluation Supporting Amend 192 to License DPR-40 ML20210D9951999-07-22022 July 1999 Safety Evaluation Supporting Amend 191 to License DPR-40 ML20216E6361999-07-21021 July 1999 Rev 18 to TDB-VI, COLR for FCS Unit 1 ML20210R2081999-06-30030 June 1999 Revised Monthly Operating Rept for June 1999 for Fcs,Unit 1 LIC-99-0065, Monthly Operating Rept for June 1999 for Fort Calhoun Station,Unit 1.With1999-06-30030 June 1999 Monthly Operating Rept for June 1999 for Fort Calhoun Station,Unit 1.With ML20196H8621999-06-30030 June 1999 NRC Regulatory Assessment & Oversight Pilot Program, Performance Indicator Data, June 1999 Rept ML20210P5461999-06-0808 June 1999 Rev 0,Vols 1-5 of Fort Calhoun Station 1999 Emergency Preparedness Exercise Manual, to Be Conducted on 990810. Pages 2-20 & 2-40 in Vol 2 & Page 4-1 in Vol 4 of Incoming Submittal Not Included ML20195B4581999-05-31031 May 1999 Rev 3 to CE NPSD-683, Development of RCS Pressure & Temp Limits Rept for Removal of P-T Limits & LTOP Requirements from Ts ML20207H7401999-05-31031 May 1999 Performance Indicators Rept for May 1999 LIC-99-0053, Monthly Operating Rept for May 1999 for Fort Calhoun Station,Unit 11999-05-31031 May 1999 Monthly Operating Rept for May 1999 for Fort Calhoun Station,Unit 1 ML20195B4521999-05-17017 May 1999 Technical Data Book TDB-IX, RCS Pressure - Temp Limits Rept (Ptlr) ML20206L4241999-05-10010 May 1999 Safety Evaluation Supporting Corrective Actions to Ensure That Valves Are Capable of Performing Intended Safety Functions & OPPD Adequately Addressed Requested Actions Discussed in GL 95-07 ML20206M2601999-05-0606 May 1999 SER Concluding That Licensee IPEEE Complete Re Info Requested by Suppl 4 to GL 88-20 & IPEEE Results Reasonable Given FCS Design,Operation & History LIC-99-0047, Monthly Operating Rept for Apr 1999 for Fort Calhoun Station Unit 1.With1999-04-30030 April 1999 Monthly Operating Rept for Apr 1999 for Fort Calhoun Station Unit 1.With ML20195E8621999-04-30030 April 1999 Performance Indicators, for Apr 1999 ML20205Q5831999-04-15015 April 1999 Safety Evaluation Supporting Amend 190 to License DPR-40 ML20210J4331999-03-31031 March 1999 Changes,Tests, & Experiments Carried Out Without Prior Commission Approval for Period 981101-990331.With USAR Changes Other than Those Resulting from 10CFR50.59 ML20206G2641999-03-31031 March 1999 Performance Indicators Rept for Mar 1999 LIC-99-0034, Monthly Operating Rept for Mar 1999 for Fcs,Unit 1.With1999-03-31031 March 1999 Monthly Operating Rept for Mar 1999 for Fcs,Unit 1.With ML20205J8181999-02-28028 February 1999 Performance Indicators, for Feb 1999 LIC-99-0025, Monthly Operating Rept for Feb 1999 for Fort Calhoun Station,Unit 1.With1999-02-28028 February 1999 Monthly Operating Rept for Feb 1999 for Fort Calhoun Station,Unit 1.With ML20207F3291999-01-31031 January 1999 FCS Performance Indicators for Jan 1999 ML20203B0991998-12-31031 December 1998 Performance Indicators for Dec 1998 LIC-99-0026, 1998 Omaha Public Power District Annual Rept. with1998-12-31031 December 1998 1998 Omaha Public Power District Annual Rept. with LIC-99-0003, Monthly Operating Rept for Dec 1998 for Fort Calhoun Station.With1998-12-31031 December 1998 Monthly Operating Rept for Dec 1998 for Fort Calhoun Station.With ML20198S3771998-12-31031 December 1998 Safety Evaluation Supporting Amend 189 to License DPR-40 ML20198S4831998-12-31031 December 1998 Safety Evaluation Supporting Amend 188 to License DPR-40 ML20196G2251998-12-18018 December 1998 Rev 2 to EA-FC-90-082, Potential Over-Pressurization of Containment Penetration Piping Following Main Steam Line Break in Containment ML20198M3141998-11-30030 November 1998 Performance Indicators Rept for Nov 1998 LIC-98-0172, Monthly Operating Rept for Nov 1998 for Fort Calhoun Station,Unit 1.With1998-11-30030 November 1998 Monthly Operating Rept for Nov 1998 for Fort Calhoun Station,Unit 1.With LIC-98-0160, Special Rept:On 981113,MSL RM RM-064 Was Declared Inoperable Due to Leakage Past Isolation Valve HCV-922.Troubleshooting Has Indicated That Leakage Has Stopped & Cause of Leak Continues to Be Investigated1998-11-25025 November 1998 Special Rept:On 981113,MSL RM RM-064 Was Declared Inoperable Due to Leakage Past Isolation Valve HCV-922.Troubleshooting Has Indicated That Leakage Has Stopped & Cause of Leak Continues to Be Investigated ML20203B0721998-11-16016 November 1998 Rev 6 to HI-92828, Licensing Rept for Spent Fuel Storage Capacity Expansion ML20196E4981998-10-31031 October 1998 Performance Indicators Rept for Oct 1998 ML20196G2441998-10-31031 October 1998 Changes,Tests & Experiments Carried Out Without Prior Commission Approval. with USAR Changes Other than Those Resulting from 10CFR50.59 LIC-98-0154, Monthly Operating Rept for Oct 1998 for Fort Calhoun Station,Unit 1.With1998-10-31031 October 1998 Monthly Operating Rept for Oct 1998 for Fort Calhoun Station,Unit 1.With ML20154M4881998-10-19019 October 1998 Safety Evaluation Supporting Amend 186 to License DPR-40 ML20154N2411998-10-19019 October 1998 Safety Evaluation Supporting Amend 187 to License DPR-40 LIC-98-0136, Monthly Operating Rept for Sept 1998 for Fort Calhoun Station,Unit 1.With1998-09-30030 September 1998 Monthly Operating Rept for Sept 1998 for Fort Calhoun Station,Unit 1.With ML20155G4261998-09-30030 September 1998 Performance Indicators for Sept 1998 ML20154A1251998-08-31031 August 1998 Performance Indicators, Rept for Aug 1998 LIC-98-0122, Monthly Operating Rept for Aug 1998 for Fort Calhoun Station Unit 1.With1998-08-31031 August 1998 Monthly Operating Rept for Aug 1998 for Fort Calhoun Station Unit 1.With ML20238F7231998-08-17017 August 1998 Owner'S Rept for Isis ML18066A2771998-08-13013 August 1998 Part 21 Rept Re Deficiency in CE Current Screening Methodology for Determining Limiting Fuel Assembly for Detailed PWR thermal-hydraulic Sa.Evaluations Were Performed for Affected Plants to Determine Effect of Deficiency 1999-09-30
[Table view] |
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Omaha Pubuc Power Distdct 444 South 16th Street Mall Omaha, Nebraska G8102-2247 402/636 2000 March 21, 1991 LIC-91-0010L U. S. Nuclear Regulatory Comission Attnt Document Control Desk Mail Station P1-137 Washington, DC 20555
Reference:
Docket No., 50-285 Gentlemen:
Subject:
Licensee Event Report 91-04 for the Fort Calhoun Station Please find attached Licensee Event Report 91-04 dated March 21, 1991. This report is being submitted pursuant to 10 CFR 50.73(a)(2)(ii)(B). A 7 day extensior, request for submittal of this report was approved by NRC Region IV personnel on March 14, 1991.
If you should have any questions, please contact me.
Sincerely,
- n. 2 2.6 W. G. Gates Division Manager Nuclear Operations
> WGG/djm Attachment ,
c: R. D. Martin, NRC Regior.31 Administrator W. C. Walker, NRC Project Manager R. P. Mullikin, NRC Senior Resident Inspector INP0 Records Center q
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- n6! i The-Offsite Power Low Sign (0PLS)providesdegradedvoltageprotectionto safeguards equipment;-when a degraded vtage condition exists concurrent with a :
Safety Injection Actuation Signal, the UPLC signal isolates safeguards buses 1A3. 1 and 1A4 from their offsite power supply (161 iW) and initiates automatic actions to load.the safeguards equipment onto the emergency diesei generators.
Engineering analysis revealed that, during a postulated accident, the voltage- '
-supplied to some 480 V safeguards loads could degrade to as low as 87.5% of rated voltage without-OPLS being actuated. Since the pcssibility existed for voltage to be lower than the recommended 90% of rated voltage for certain 480 V
-safeguards loads without an OPLS actuation, managenient determined on February 12, 1991 that the plant was outside of its design basis.
- Corrective actions include administrative controls of equipment configurations U,d bus' loadings,. as well as rest.tting of the OPLS setpoints. A long term
. corrective action plan is-being developed.
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010 012 F 0l5 At Fort Calhoun Station the electrical distribution system is designed with foui separate 4160 Y buses, two of which (1A3 and 1A4) are designated as safeguards buses. These 4160 V safeguards buses are normally fed from the 161 KV system which constitute the offsite power supply. The two safeguards buses and their associated 480 casessuplypowertoEngineeredSafetyFeature(ESF) components that are required for safe reactor shutdown and removal of decay heat. To ensure that adequate voltage exists from the offsite power sys+ m to these buses during an accident, the electrical distribution system has been equipped with a degraded voltage protection system. Thedegradedvolta protectionsystemisreferredtoastheOffsitePowerLowSignal(0PLS)ge . The OPLS provides protection to safeguards equipment when an undervoltage confition is sensed on buses 1A3 or 1A4, in the presence of a Safety Injection Actuation Signal (SIAS). When a degraded voltage condition exists concurrent ith a SIAS, the OPLS signal isolates buses 1A3 u.. lA4 from their offsite power supply (161 KV) and Mitiates automatic actioas to load the safeguards equipment nto the emergency diesel generators. The OPLS setpoints were originally designed to
-ensure ths voltage being supplied to the C 60 V and 480 V loads does not d..
below 90s of nameplate voltage during a accident. The motor manufacturer recommends that terminal voltage be maintained at a minimum of 90% of motor nameplate rating to assure _long-term motor protection fro. excessive current.
Omaha Public Power bistrict (0 PPD) has been involved in a Jesign Basis Reconstitution Project to verify or reconstruct the design basis calculations and analyses of Fort Calhoun Station systems including the electricai distribution system. In 1989, the first revision of-the Design Basis Document for the electrical distribution syscam was issued. An open item in this document-identified the lack of supporting documentation to verify that certain loads could be assured of operating above their minimum voltage rating. In an effort to resolve this open item 3 computer software program, " Electrical Load Monitoring System" (ELMS), was utilized to model the plant electrical distribution system for purposes of reconstituting the original Degraded Voltage Analysis. The ELMS revealed that during an accident in which safeguard equipment would be recuired to operate, the voltage supplied to some 480 V safeguards loads coulc degrade to as low as 87.5% of rated voltage without OPLS being actuated. Since the possibility existed for voltage to be lower than the recommended 90t Of rated voltage for certain 480 V safeguards loads without an OPLS actuation, the Pla M Review Committee (PRC) determined on February 12, 1991 that the )lant was outside of its design basis. The PRC concluded that OPLS was operable )ased upon engineering judgement that the safeguards loads would continue to perform their intended functions at the degraded voltage. The plant l
-was at 75% power and mode 1 at the time of the determination.
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-o m a Nne m m nn A.one hour report was subsequently made to the NRC at 1615 hours on February 12, 1991 in accordance with 10 CFR 50.72(b)(1 This written report is
- submittedpursuantto10CFR50.7;(a)(2)()(ii)(B). ii)(B) for the plant being outside its design basis. A 7 day extension request for submittal of this report was approved by.NRC Region IV pe,;onnel on March 14, 1991.
As a result of OPPD's effort to reconstitute the original Degraded Voltage Analysit, several modifications were identified that have contributed to degrading the plant uMervoltage protection capabilities. Initially, the OPLS degraded voltage protection system n installed in 1970 under modification MR-FC-77-064 in response to a NRC generic letter or degraded voltage, dated June 2, 1977. During a recent review of design basis d 'nents, it was discovered
-that the original analysis performed in support M .ne modification did not
-assume the worst case loading that would occur during a Loss of Coolant Accident
-(LOCA) scenario. The load model used in the original analysis was not representative of these worst case operating conditions and thus did not cor,servatively assume the loads that would be present. This potentially could
-allow a condition in which voltage on the 480 V buses could decrease below 90%
of rated' voltage without having reached the original OPLS actuation setpoints.
Another concern identified was modification MR-FC-84-105, com leted in 1985, which r9placed t % 4160/480-V transformers with those of a hi her-impedance. ,
- The hignerL1mpedance transformers were selected in order to 1 mit ground fault currents available:to the 480 V switchgear. This also resulted in lower 480 V 1 system voltages due to the higher im3edances. Although the analysis concluded
, that voltage levels were acceptable.)ased on operator action to trip various '
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.large41oads during a accident,-these assumptions were invalid since they took credit for 9anual action to reduce system loads during post !.0CA operation.
3 Recent-reviewoftheoriginallicensingbasisdegradedvoltage(OPLS) submittal to the F.C on August 30, 1978, indicates:that these assumptions do not meet design criteria for " automatic" protection of ESF loads for undervoltage
- conditionsiin a post-LOCA condition. y 7
l :In 1986,'an engineering consultant was-contracted to update the electrical E "distribui.ien-system's design. basis documents for future modifications and verify r the-0PLS operating setpoints.- On November 3, 1988, plant management was
; notified of the results of the report. It was identified that the-possibility
. existed for the 4160 V-buses to trip from their offs' 'ower supply (161KV) during accident conditions. It appeared tnat during 4..ident conditione N
assu.:ing safeguards bus 1A4 at its heaviest normt.1 loading,161 KV griu at its lowest normal. expected voltage, and ESF equipment sequenced onto the buses _
ifollowing a Safety udection Actuation Signat OPLS actuation would occur while offsite power was in a normal voltage range. LER 88-31 was submitted to the NRC h documenting the condition and corrective action.
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-To correct the problem, Modification MR-FC-88-110 was installed in 1988 to increase various safeguards equi > ment sequencer starting times until system starting loads had decreased. Tie analysis performed in support of the >
; modification took credit for operator action to reduce certain 4160 V loads in
-order to increase system voltage. Although it wasn't realized at the time, -
l credits:ould not be taken for reducing system loads by means of non-automatic protection of.ESF equipment. As previously stated, this type of load reduction does~not meet design criteria for " automatic" protection of ESF loads for undervoltage conditions-in a post-LOCA condition.
Because the OPLS'was determined to be outside its design basis on February 12, 1991, an engineering evaluation was performed to determine the effects of degraded voltage on the' safeguards equipment, specifically the 480.V, motors. -By considering-the-time overcurrent protection curves for safeguards loads, it was concluded that sufficient mergin exists such that the safeguard equipment would be able to operate without tripping during a Design Basis Accident with an undervoltage condition on the 161 KV system. The estimated motor overload currents would not be expected to generate sufficient heating of the motor internals over the-required cporating times that would preclude acceptable ,
equipment performance. This justification is based on engineering judgement.
.The primary cause of this event can be attributed to an inadequate modification design at the time'the-original Degraded Voltage Analysis was performed. The -
assumption made-in the original analysis was nonconservative and has propagated throughout subsequent _ revisions to the t ' lysis.. A-contributing cause was lack of procedural guidance for the performanci. W documentation of-r.ssumptions used in the calculations. Another contributing use was lack of comprehensive '
DesignBasisDocumentationpriortoJuly,)! N This resulted in inadequate documentation of the original 0PLS design ci aria which led to credit being -
taken in subsequent modifications for non-automatic' protection of-safeguards loads. These primary and contributing causes have already been corrected Lthroughlthe development of upgraded procedures for the control of calculations and documentation _ requirements. Additionally, the development and issuance of L ; plant-Design Basis Documents have provided the corrective action necessary for resolution of. incomplete design basis documentation.
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.The'following ccmpensatory measures were t'aken to ensure the operability of~the degraded voltage _ system (OPLS) and thus assure the satisfactory performance of 4 sthe safeguards motors: !
(1) Engineering analysit EA-FC-91-017:was performed to derive new OPLS setpoints Lfor-current bus loading configurations. The new setpoints'are more conservative than the setpoints currently listed in the-Technical Specifications. The OPLS actuation relays have been recalibrated with the ;
new setpoints-designated-in-EA-FC-91-017. The new OPLS setpoints in !
conjunction with the= 1oadire;; configuration specified in the analysis will !
ensure safeguards-motors.arr capable of satisfying their design function during accident conditions. :
(2)- Administrati'?" restrictions were placed on equipment rotation =' bus loading configurations through Operations Memorandum FC-91-02. iiie loading restrictions are necessary to ensure bus alignment is consistent with that H assumed in the analysis for the new setpoints. Administrative bus loading restrictions will remain in effect until long term' corrective action has-been completed. If an electrical configuration-arises-due to plaat operating requirements which are outside the permitted restrictions, plant
-staff will contact Engineering, evaluate the situation, and-determine '
e operability and reportability.
e(3)- As an interim measure until the new OPLS setpoints wer a installed, a ;
; dedicated operator was stationed in the control room to monitor voltage j
. levels _on 4160 V buses 1A3 and 1A4 and manually actuate OPLS if voltages
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dropped below the new OPLS alarm.setpoints1 installed on the plaret computer.
'A plan for long-term corrective action is being developed to remove administrative operating restrictions. Highlights of this. plan will be provided b in a supplement to this LER:by June 21,:1991.
# t0ther Licensce Event' Reports which have been submitted addressing design deficiencies are LERs 90-03, 90-05, 90-07, 90-09,- 90-16, 90-20, 90-23, 90-25,-
t89-09,-89-14, 89-15, 89-24,.88-09, 88-19,.88-20, 88;32,-and'88-33.
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