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Category:LICENSEE EVENT REPORT (SEE ALSO AO
MONTHYEARML17292B7421999-07-20020 July 1999 LER 99-001-00:on 990628,ESF Signal Closed All Eight MSIVs While Plant Was Shutdown.Caused by Failure of Relay RPS-RLY-K10D.Subject Relay Was Replaced & Tested on 990630. with 990720 Ltr ML17292B4451998-10-27027 October 1998 LER 98-012-01:on 980715,failure to Comply with Requirements of TS SR 3.8.4.7 Was Noted.Caused by Inadequate Work Practices.Training Session Was Held with Personnel.With 981027 Ltr ML17284A7561998-09-0303 September 1998 LER 98-013-00:on 980805,ESF Actuations Were Noted Due to Deenergization of Vital Electrical Bus SM-8.Caused by Inadequate Direction in Troubleshooting Plan.Will Conduct Training for Engineering Personnel.With 980903 Ltr ML17284A7571998-09-0202 September 1998 LER 98-014-00:on 980807,completion of TS 3.8.1.F Required Shutdown Due to Inoperability of EDG-2 Was Noted.Caused by Degraded Voltage Regulator for DG-2.Replaced Voltage Regulator & Associated Scrs.With 980902 Ltr ML17284A7551998-09-0202 September 1998 LER 98-015-00:on 980808,discovered Reactor Coolant Pressure Boundary Leak During Shutdown Conditions.Caused by Leakage from Socket Weld (Fwb 63) on Elbow Connection.Failed Piping Connection Was Replaced.With 980902 Ltr ML17284A7311998-08-17017 August 1998 LER 98-012-00:on 980716,determined That 24-month SR 3.8.4.7 Had Not Been Fulfilled within Specified Frequency.Caused by Inadequate Work Practices.License Requested & Received Enforcement Discretion Re Battery Svc test.W/980817 Ltr ML17284A7121998-07-23023 July 1998 LER 98-006-01:on 980520,discovered Discrepancies in Low Voltage Bus Calculations During Review of 10CFR50,App R Calculations for High Impedance Faults.Caused by Inadequate Work Practices.Implemented Procedural Changes ML17284A6951998-07-17017 July 1998 LER 98-011-00:on 980617,ECCS Pump Room Flooding Was Noted Due to FP Sys Pipe Break.Caused by Inadequate Design of FP Sys.Detailed Review of FP Sys Design Was Conducted. W/980717 Ltr ML17284A6961998-07-15015 July 1998 LER 98-010-00:on 980615,TS Required Shutdown Due to Inoperability of TIP Sys Isolation Valve Was Noted.Caused by Improper Installation of TIP Tubing.Reattached Affected Tubing & Inspected Other TIP tubing.W/980715 Ltr ML17284A6731998-07-0101 July 1998 LER 98-009-00:on 980606,nuclear Steam Supply Shutoff Sys Group 3 & 4 Isolations During Testing Was Noted.Caused by Procedural Deficiency.Counseled Individuals Involved in preparation.W/980701 Ltr ML17284A6651998-06-24024 June 1998 LER 98-007-00:on 980530,inadvertent Full Scram & Division 1 ECCS Injection Was Noted.Caused by Failure to Meet Mgt Work Practice Expectation When Encountering Deficient Procedure. Incident Review Board Convened to Review event.W/980624 Ltr ML17284A6641998-06-24024 June 1998 LER 98-008-00:on 980531,inadvertent Full Scram During RPV Leak Testing in Mode 4 Was Noted.Caused by Change in Mgt Techniques.Revised Procedures to Take Into Account Addl Water Head in Pressure Sensing lines.W/980624 Ltr ML17284A6631998-06-19019 June 1998 LER 98-006-00:on 980520,discovered Discrepancies in Low Voltage Bus Calculations During Review of App R Calculations for High Impedance Fault Analysis.Caused Indeterminate. Implemented Procedural Changes Involving Operator Action ML17284A6551998-06-0404 June 1998 LER 98-005-00:on 980506,potential for Failure of RHR Sys Valve to Close on Isolation Signal Was Noted.Caused by Design Deficiency.Caution Tag Was Placed on RHR-V-40 Control Switch to Inform Plant Operators of limitation.W/980604 Ltr ML17284A6421998-06-0101 June 1998 LER 98-004-00:on 980502,determined That Primary Containment Penetration Overcurrent Protection Does Not Meet Reg Guide 1.63 Requirements.Caused by Inadequate Design Changes. Installed Addl Fuse in RHR-MO-9 circuit.W/980601 Ltr ML17292B3281998-04-0909 April 1998 LER 98-002-00:on 980311,reactor Scram & Plant Transient Occurred,Due to Failed Closed Main Steam Isolation Valve. Caused by Loss of Pneumatic Actuating Supply Pressure. Problem Evaluation Request Written for Failure of MS-V-22D ML17292B3291998-04-0909 April 1998 LER 98-003-00:on 980311,WNP-2 Experienced SCRAM Signal as Result of Low Rpv.Caused by Less than post-SCRAM Operational Strategy for Resetting SCRAM Signal in Conditions.Changes in post-SCRAM Operational Strategy implemented.W/980409 Ltr ML17292B2661998-03-0404 March 1998 LER 98-001-00:on 980203,automatic Start of HPCS EDG Was Noted.Caused by Operator Error.Operations Crew Stabilized Plant at Approximately 75% Reactor Power & Investigation of Event Was initiated.W/980304 Ltr ML17292B1111997-11-10010 November 1997 LER 97-011-00:on 971010,HPCS Battery Charger Failed.Caused by Failure of a Phase Firing Control Circuit Board Due to Aging During 7 Yrs of Use.Hpcs Sys Was Immediately Declared inoperable.W/971110 Ltr ML17292B1151997-11-0707 November 1997 LER 97-010-00:on 970906,discovered That TS SR 3.4.5.1 for Identified Portion of RCS Total Leakage Would Not Be Able to Perform within Time Limits of SR 3.0.2.Caused by Inadequate Methods.Method of Meeting SR 3.4.5.1 Established ML17292B0641997-09-24024 September 1997 LER 97-004-01:on 970327,plant Operators Manually Scrammed Reactor as Required by TS Due to Indication of Entry Into Region a of power-to-flow Map.Caused by Inadequate Attention to Detail.Established Event Evaluation teams.W/970924 Ltr ML17292B0241997-08-18018 August 1997 LER 97-009-00:on 970717,discovered Error in Recently Performed Inservice Testing procedure,OSP-TIP/IST-R701. Caused by Procedure Inadequacy.Plant Procedure OSP/TIP/IST-R701 Will Be changed.W/970818 Ltr ML17292B0291997-08-15015 August 1997 LER 97-008-00:on 970716,wire Seal Used to Lock Containment Instrument Air Pressure Control valve,CIA-PCV-2B,found Not Intact.Cause of Misadjustment of CIA-PCV-2B Unknown.Event Will Be Communicated to Plant employees.W/970815 Ltr ML17292B0201997-08-15015 August 1997 LER 97-S01-00:on 970718,failure to Take Compensatory Measure for Inoperative Microwave Security Zone Occurred. Caused by Personnel Error.Training Will Be Conducted W/ Appropriate Members of Security force.W/970815 Ltr ML17292A9481997-07-23023 July 1997 LER 97-007-00:on 970611,voluntary Rept of Automatic Start of DG-1 & DG-2 Was Experienced.Caused by Undervoltage Condition on Electrical Busses SM-7 & SM-8.Circulating Water Pump CW-P-1C Control Switch Placed in pull-to-lock.W/970723 Ltr ML17292A9201997-06-26026 June 1997 LER 97-006-00:on 970527,non-performance of Surveillance Requirement 3.6.1.3.2 for Blind Fanges,Was Noted.Caused Because Misunderstanding of Intent of Specs.Added Five Structural Assemblies for SP.W/970626 Ltr ML17292A8331997-04-28028 April 1997 LER 97-004-00:on 970327,plant Operators Manually Scrammed Reactor as Required by TS Due to Entry Into Region a of power-to-flow Map Following Planned Trip of Single Mfp. Event Evaluation teams,established.W/970428 Ltr ML17292A8311997-04-28028 April 1997 LER 97-005-00:on 970327,valid Reactor Scram Signal Received Due to Low Water Level Condition During Preparations for SRV Testing.Caused by Risks & Consequences of Decisions Not Completely Identified.Restored Water level.W/970428 Ltr ML17292A8251997-04-21021 April 1997 LER 97-003-00:on 970320,notification of Noncompliance W/Ts as TS SRs for Response Time Testing Were Not Being Met for Specified Instrumentation in Rps,Pcis & Eccs.Requested Enforcement Discretion for One Time exemption.W/970421 Ltr ML17292A7431997-03-20020 March 1997 LER 97-002-00:on 970218,determined That Rod Block Monitor (RBM) Calibr Values Were Not Set IAW Tech Specs.Caused by Calibr Procedures Inadequacies.Revised & re-performed RBM Channel Calibr procedures.W/970330 Ltr ML17292A7401997-03-13013 March 1997 LER 97-001-00:on 970211,reactor Water Cleanup Sys Blowdown Flow Isolation Setpoint Was Slightly Above TS Allowable Valve Occurred Due to Calculation Error.Lds Fss LD-FS-15 LD-FS-16 Were Declared inoperable.W/970313 Ltr ML17292A6641997-01-22022 January 1997 LER 96-009-00:on 961220,miscalculation of Instantaneous Overcurrent Relay Settings Resulted in Inoperability of safety-related Equipment.Caused by Utilization of Inappropriate Design.Testing Was completed.W/970122 Ltr ML17292A6461997-01-0606 January 1997 LER 96-008-00:on 961205,failure to Comply with TS Action Requirement for Emergency Core Cooling Sys Actuation Instrumentation Occurred Due to Unidentified Inoperability Condition.Pmr initiated.W/970106 Ltr ML17292A6371996-12-19019 December 1996 LER 96-007-00:on 961122,electrical Breakers Were Not Seismically Qualified in Test/Disconnect Position.Circuit Breaker Mfg Did Not Consider Raced Out Breaker Position During Testing.Relocated Circuit breakers.W/961217 Ltr ML17292A4121996-08-0808 August 1996 LER 96-006-00:on 960709,average Power Range Monitor Rod Block Downscale Surveillance Not Performed Prior to Entry Into Mode 1.Caused by long-standing Misinterpretation of Requirements of Tss.Procedures revised.W/960808 Ltr ML17292A3801996-07-24024 July 1996 LER 96-004-00:on 960624,plant Was Manually Scrammed by Control Room Personnel Due to Reactor Water Level Transient Experienced During Testing of Digital Feedwater Sys.Caused by Programming Error.Sys Was corrected.W/960724 Ltr ML17292A3771996-07-24024 July 1996 LER 96-005-00:on 960624,determined Missed Surveillance Test Re Channel Check of Average Power Range Monitor.Caused by Inadequate Procedures.Revised Surveillance Procedure Re When APRM Checks Must Be performed.W/960724 Ltr ML17292A3641996-07-12012 July 1996 LER 96-003-00:on 960615,required Surveillance Test Not Performed When Required by TS 3.4.1.3.Caused by Inadequate Procedures.Implementing Surveillance Procedure & Reactor Plant Startup Procedures revised.W/960712 Ltr ML17292A3361996-06-20020 June 1996 LER 96-002-00:on 960504,critical Bus SM-8 Lost Power When Supply Breaker 3-8 Tripped.Caused by Personnel Error. Operators Counselled & Procedures revised.W/960620 Ltr ML17292A2861996-05-24024 May 1996 LER 96-001-00:on 960425,inadvertent ESF Actuations Occurred Due to Tripping of Temporary Power Supply to IN-3.Caused by Personnel Error.Operations Restored to IN-3 Loads & Reset ESF actuations.W/960524 Ltr ML17291B0891995-10-19019 October 1995 LER 95-011-00:on 950919,failed to Comply W/Ts SR for RCIC Sys Due to Analysis Deficiency That Resulted in Inadequate Surveillance Test Procedure.Surveillance Procedure Revised to Correct deficiency.W/951019 Ltr ML17291A9021995-07-0707 July 1995 LER 95-010-00:on 950609,HPCS DG Declared Inoperable Due to Discovery That TS Test Method Incomplete.Caused by Inadequate Testing Procedure.Test Procedure for HPCS DG Reviewed & Special Test Procedures written.W/950707 Ltr ML17291A9031995-07-0707 July 1995 LER 95-009-00:on 950607,inadvertent MSIV Closure Occurred During Surveillance Test Due to Poor Communication Between Test Team.Determined That MSIV Closure Not Valid Because Closure Not Triggered by Plant conditions.W/950707 Ltr ML17291A8501995-06-0808 June 1995 LER 95-006-01:on 950405,reactor Scram Occurred During Surveillance Testing Due to Protective Sys Relay Failure. Replaced Failed Relay Before Plant Startup ML17291A8101995-05-12012 May 1995 LER 95-008-00:on 940125,TS Wording Lead to Potential TS Violation.Caused by Lack of Clarity in Ts.Submitted Improved TS for Plant to Provide Addl clarity.W/950512 Ltr ML17291A7841995-05-0505 May 1995 LER 95-007-00:on 950222,emergency Diesel Start Occurred Due to Voltage Transient on BPA Grid.Confirmation Was Received at 17:51 H That Disturbance Had Originated in BPA Grid ML17291A7801995-05-0404 May 1995 LER 95-006-00:on 950405,main Turbine Trip Occurred During Performance of Surveillance Test Due to Protective Sys Relay Failed.Replaced Failed Relay Before Plant startup.W/950504 Ltr ML17291A7851995-05-0303 May 1995 LER 95-005-00:on 950222,inoperable IRM Had Been Relied Upon to Meet TS Requirements During Reactor Startup.Caused by Lack of Neutron Source to Test Instrumentation. Sys Knowledge Gained Will Be incorporated.W/950503 Ltr ML17291A7071995-03-25025 March 1995 LER 95-004-00:on 950226,malfunction in Main Turbine DEH Control Sys Caused All Four High Pressure Turbine Governor Valves to Rapidly Close.Caused by Blown Fuse.Suspected Faulty Circuit Card replaced.W/950325 Ltr ML17291A7011995-03-20020 March 1995 LER 95-002-00:on 950218,automatic Reactor Scram Occurred. Caused by Erroneous Positioning of Control During Performance of Scheduled Periodic Functional Test.Control repositioned.W/950320 Ltr 1999-07-20
[Table view] Category:RO)
MONTHYEARML17292B7421999-07-20020 July 1999 LER 99-001-00:on 990628,ESF Signal Closed All Eight MSIVs While Plant Was Shutdown.Caused by Failure of Relay RPS-RLY-K10D.Subject Relay Was Replaced & Tested on 990630. with 990720 Ltr ML17292B4451998-10-27027 October 1998 LER 98-012-01:on 980715,failure to Comply with Requirements of TS SR 3.8.4.7 Was Noted.Caused by Inadequate Work Practices.Training Session Was Held with Personnel.With 981027 Ltr ML17284A7561998-09-0303 September 1998 LER 98-013-00:on 980805,ESF Actuations Were Noted Due to Deenergization of Vital Electrical Bus SM-8.Caused by Inadequate Direction in Troubleshooting Plan.Will Conduct Training for Engineering Personnel.With 980903 Ltr ML17284A7571998-09-0202 September 1998 LER 98-014-00:on 980807,completion of TS 3.8.1.F Required Shutdown Due to Inoperability of EDG-2 Was Noted.Caused by Degraded Voltage Regulator for DG-2.Replaced Voltage Regulator & Associated Scrs.With 980902 Ltr ML17284A7551998-09-0202 September 1998 LER 98-015-00:on 980808,discovered Reactor Coolant Pressure Boundary Leak During Shutdown Conditions.Caused by Leakage from Socket Weld (Fwb 63) on Elbow Connection.Failed Piping Connection Was Replaced.With 980902 Ltr ML17284A7311998-08-17017 August 1998 LER 98-012-00:on 980716,determined That 24-month SR 3.8.4.7 Had Not Been Fulfilled within Specified Frequency.Caused by Inadequate Work Practices.License Requested & Received Enforcement Discretion Re Battery Svc test.W/980817 Ltr ML17284A7121998-07-23023 July 1998 LER 98-006-01:on 980520,discovered Discrepancies in Low Voltage Bus Calculations During Review of 10CFR50,App R Calculations for High Impedance Faults.Caused by Inadequate Work Practices.Implemented Procedural Changes ML17284A6951998-07-17017 July 1998 LER 98-011-00:on 980617,ECCS Pump Room Flooding Was Noted Due to FP Sys Pipe Break.Caused by Inadequate Design of FP Sys.Detailed Review of FP Sys Design Was Conducted. W/980717 Ltr ML17284A6961998-07-15015 July 1998 LER 98-010-00:on 980615,TS Required Shutdown Due to Inoperability of TIP Sys Isolation Valve Was Noted.Caused by Improper Installation of TIP Tubing.Reattached Affected Tubing & Inspected Other TIP tubing.W/980715 Ltr ML17284A6731998-07-0101 July 1998 LER 98-009-00:on 980606,nuclear Steam Supply Shutoff Sys Group 3 & 4 Isolations During Testing Was Noted.Caused by Procedural Deficiency.Counseled Individuals Involved in preparation.W/980701 Ltr ML17284A6651998-06-24024 June 1998 LER 98-007-00:on 980530,inadvertent Full Scram & Division 1 ECCS Injection Was Noted.Caused by Failure to Meet Mgt Work Practice Expectation When Encountering Deficient Procedure. Incident Review Board Convened to Review event.W/980624 Ltr ML17284A6641998-06-24024 June 1998 LER 98-008-00:on 980531,inadvertent Full Scram During RPV Leak Testing in Mode 4 Was Noted.Caused by Change in Mgt Techniques.Revised Procedures to Take Into Account Addl Water Head in Pressure Sensing lines.W/980624 Ltr ML17284A6631998-06-19019 June 1998 LER 98-006-00:on 980520,discovered Discrepancies in Low Voltage Bus Calculations During Review of App R Calculations for High Impedance Fault Analysis.Caused Indeterminate. Implemented Procedural Changes Involving Operator Action ML17284A6551998-06-0404 June 1998 LER 98-005-00:on 980506,potential for Failure of RHR Sys Valve to Close on Isolation Signal Was Noted.Caused by Design Deficiency.Caution Tag Was Placed on RHR-V-40 Control Switch to Inform Plant Operators of limitation.W/980604 Ltr ML17284A6421998-06-0101 June 1998 LER 98-004-00:on 980502,determined That Primary Containment Penetration Overcurrent Protection Does Not Meet Reg Guide 1.63 Requirements.Caused by Inadequate Design Changes. Installed Addl Fuse in RHR-MO-9 circuit.W/980601 Ltr ML17292B3281998-04-0909 April 1998 LER 98-002-00:on 980311,reactor Scram & Plant Transient Occurred,Due to Failed Closed Main Steam Isolation Valve. Caused by Loss of Pneumatic Actuating Supply Pressure. Problem Evaluation Request Written for Failure of MS-V-22D ML17292B3291998-04-0909 April 1998 LER 98-003-00:on 980311,WNP-2 Experienced SCRAM Signal as Result of Low Rpv.Caused by Less than post-SCRAM Operational Strategy for Resetting SCRAM Signal in Conditions.Changes in post-SCRAM Operational Strategy implemented.W/980409 Ltr ML17292B2661998-03-0404 March 1998 LER 98-001-00:on 980203,automatic Start of HPCS EDG Was Noted.Caused by Operator Error.Operations Crew Stabilized Plant at Approximately 75% Reactor Power & Investigation of Event Was initiated.W/980304 Ltr ML17292B1111997-11-10010 November 1997 LER 97-011-00:on 971010,HPCS Battery Charger Failed.Caused by Failure of a Phase Firing Control Circuit Board Due to Aging During 7 Yrs of Use.Hpcs Sys Was Immediately Declared inoperable.W/971110 Ltr ML17292B1151997-11-0707 November 1997 LER 97-010-00:on 970906,discovered That TS SR 3.4.5.1 for Identified Portion of RCS Total Leakage Would Not Be Able to Perform within Time Limits of SR 3.0.2.Caused by Inadequate Methods.Method of Meeting SR 3.4.5.1 Established ML17292B0641997-09-24024 September 1997 LER 97-004-01:on 970327,plant Operators Manually Scrammed Reactor as Required by TS Due to Indication of Entry Into Region a of power-to-flow Map.Caused by Inadequate Attention to Detail.Established Event Evaluation teams.W/970924 Ltr ML17292B0241997-08-18018 August 1997 LER 97-009-00:on 970717,discovered Error in Recently Performed Inservice Testing procedure,OSP-TIP/IST-R701. Caused by Procedure Inadequacy.Plant Procedure OSP/TIP/IST-R701 Will Be changed.W/970818 Ltr ML17292B0291997-08-15015 August 1997 LER 97-008-00:on 970716,wire Seal Used to Lock Containment Instrument Air Pressure Control valve,CIA-PCV-2B,found Not Intact.Cause of Misadjustment of CIA-PCV-2B Unknown.Event Will Be Communicated to Plant employees.W/970815 Ltr ML17292B0201997-08-15015 August 1997 LER 97-S01-00:on 970718,failure to Take Compensatory Measure for Inoperative Microwave Security Zone Occurred. Caused by Personnel Error.Training Will Be Conducted W/ Appropriate Members of Security force.W/970815 Ltr ML17292A9481997-07-23023 July 1997 LER 97-007-00:on 970611,voluntary Rept of Automatic Start of DG-1 & DG-2 Was Experienced.Caused by Undervoltage Condition on Electrical Busses SM-7 & SM-8.Circulating Water Pump CW-P-1C Control Switch Placed in pull-to-lock.W/970723 Ltr ML17292A9201997-06-26026 June 1997 LER 97-006-00:on 970527,non-performance of Surveillance Requirement 3.6.1.3.2 for Blind Fanges,Was Noted.Caused Because Misunderstanding of Intent of Specs.Added Five Structural Assemblies for SP.W/970626 Ltr ML17292A8331997-04-28028 April 1997 LER 97-004-00:on 970327,plant Operators Manually Scrammed Reactor as Required by TS Due to Entry Into Region a of power-to-flow Map Following Planned Trip of Single Mfp. Event Evaluation teams,established.W/970428 Ltr ML17292A8311997-04-28028 April 1997 LER 97-005-00:on 970327,valid Reactor Scram Signal Received Due to Low Water Level Condition During Preparations for SRV Testing.Caused by Risks & Consequences of Decisions Not Completely Identified.Restored Water level.W/970428 Ltr ML17292A8251997-04-21021 April 1997 LER 97-003-00:on 970320,notification of Noncompliance W/Ts as TS SRs for Response Time Testing Were Not Being Met for Specified Instrumentation in Rps,Pcis & Eccs.Requested Enforcement Discretion for One Time exemption.W/970421 Ltr ML17292A7431997-03-20020 March 1997 LER 97-002-00:on 970218,determined That Rod Block Monitor (RBM) Calibr Values Were Not Set IAW Tech Specs.Caused by Calibr Procedures Inadequacies.Revised & re-performed RBM Channel Calibr procedures.W/970330 Ltr ML17292A7401997-03-13013 March 1997 LER 97-001-00:on 970211,reactor Water Cleanup Sys Blowdown Flow Isolation Setpoint Was Slightly Above TS Allowable Valve Occurred Due to Calculation Error.Lds Fss LD-FS-15 LD-FS-16 Were Declared inoperable.W/970313 Ltr ML17292A6641997-01-22022 January 1997 LER 96-009-00:on 961220,miscalculation of Instantaneous Overcurrent Relay Settings Resulted in Inoperability of safety-related Equipment.Caused by Utilization of Inappropriate Design.Testing Was completed.W/970122 Ltr ML17292A6461997-01-0606 January 1997 LER 96-008-00:on 961205,failure to Comply with TS Action Requirement for Emergency Core Cooling Sys Actuation Instrumentation Occurred Due to Unidentified Inoperability Condition.Pmr initiated.W/970106 Ltr ML17292A6371996-12-19019 December 1996 LER 96-007-00:on 961122,electrical Breakers Were Not Seismically Qualified in Test/Disconnect Position.Circuit Breaker Mfg Did Not Consider Raced Out Breaker Position During Testing.Relocated Circuit breakers.W/961217 Ltr ML17292A4121996-08-0808 August 1996 LER 96-006-00:on 960709,average Power Range Monitor Rod Block Downscale Surveillance Not Performed Prior to Entry Into Mode 1.Caused by long-standing Misinterpretation of Requirements of Tss.Procedures revised.W/960808 Ltr ML17292A3801996-07-24024 July 1996 LER 96-004-00:on 960624,plant Was Manually Scrammed by Control Room Personnel Due to Reactor Water Level Transient Experienced During Testing of Digital Feedwater Sys.Caused by Programming Error.Sys Was corrected.W/960724 Ltr ML17292A3771996-07-24024 July 1996 LER 96-005-00:on 960624,determined Missed Surveillance Test Re Channel Check of Average Power Range Monitor.Caused by Inadequate Procedures.Revised Surveillance Procedure Re When APRM Checks Must Be performed.W/960724 Ltr ML17292A3641996-07-12012 July 1996 LER 96-003-00:on 960615,required Surveillance Test Not Performed When Required by TS 3.4.1.3.Caused by Inadequate Procedures.Implementing Surveillance Procedure & Reactor Plant Startup Procedures revised.W/960712 Ltr ML17292A3361996-06-20020 June 1996 LER 96-002-00:on 960504,critical Bus SM-8 Lost Power When Supply Breaker 3-8 Tripped.Caused by Personnel Error. Operators Counselled & Procedures revised.W/960620 Ltr ML17292A2861996-05-24024 May 1996 LER 96-001-00:on 960425,inadvertent ESF Actuations Occurred Due to Tripping of Temporary Power Supply to IN-3.Caused by Personnel Error.Operations Restored to IN-3 Loads & Reset ESF actuations.W/960524 Ltr ML17291B0891995-10-19019 October 1995 LER 95-011-00:on 950919,failed to Comply W/Ts SR for RCIC Sys Due to Analysis Deficiency That Resulted in Inadequate Surveillance Test Procedure.Surveillance Procedure Revised to Correct deficiency.W/951019 Ltr ML17291A9021995-07-0707 July 1995 LER 95-010-00:on 950609,HPCS DG Declared Inoperable Due to Discovery That TS Test Method Incomplete.Caused by Inadequate Testing Procedure.Test Procedure for HPCS DG Reviewed & Special Test Procedures written.W/950707 Ltr ML17291A9031995-07-0707 July 1995 LER 95-009-00:on 950607,inadvertent MSIV Closure Occurred During Surveillance Test Due to Poor Communication Between Test Team.Determined That MSIV Closure Not Valid Because Closure Not Triggered by Plant conditions.W/950707 Ltr ML17291A8501995-06-0808 June 1995 LER 95-006-01:on 950405,reactor Scram Occurred During Surveillance Testing Due to Protective Sys Relay Failure. Replaced Failed Relay Before Plant Startup ML17291A8101995-05-12012 May 1995 LER 95-008-00:on 940125,TS Wording Lead to Potential TS Violation.Caused by Lack of Clarity in Ts.Submitted Improved TS for Plant to Provide Addl clarity.W/950512 Ltr ML17291A7841995-05-0505 May 1995 LER 95-007-00:on 950222,emergency Diesel Start Occurred Due to Voltage Transient on BPA Grid.Confirmation Was Received at 17:51 H That Disturbance Had Originated in BPA Grid ML17291A7801995-05-0404 May 1995 LER 95-006-00:on 950405,main Turbine Trip Occurred During Performance of Surveillance Test Due to Protective Sys Relay Failed.Replaced Failed Relay Before Plant startup.W/950504 Ltr ML17291A7851995-05-0303 May 1995 LER 95-005-00:on 950222,inoperable IRM Had Been Relied Upon to Meet TS Requirements During Reactor Startup.Caused by Lack of Neutron Source to Test Instrumentation. Sys Knowledge Gained Will Be incorporated.W/950503 Ltr ML17291A7071995-03-25025 March 1995 LER 95-004-00:on 950226,malfunction in Main Turbine DEH Control Sys Caused All Four High Pressure Turbine Governor Valves to Rapidly Close.Caused by Blown Fuse.Suspected Faulty Circuit Card replaced.W/950325 Ltr ML17291A7011995-03-20020 March 1995 LER 95-002-00:on 950218,automatic Reactor Scram Occurred. Caused by Erroneous Positioning of Control During Performance of Scheduled Periodic Functional Test.Control repositioned.W/950320 Ltr 1999-07-20
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML17284A9001999-10-31031 October 1999 Rev 0 to COLR 99-15, WNP-2 Cycle 15,COLR GO2-99-177, LER 99-S01-00:on 990903,failure to Take Compensatory Measure within Required Time Upon Failure of Isolation Zone Microwave Unit,Was Noted.Caused by Personnel Error.Provided Refresher Training on Compensatory Measures.With1999-10-0101 October 1999 LER 99-S01-00:on 990903,failure to Take Compensatory Measure within Required Time Upon Failure of Isolation Zone Microwave Unit,Was Noted.Caused by Personnel Error.Provided Refresher Training on Compensatory Measures.With ML17284A8941999-09-30030 September 1999 Monthly Operating Rept for Sept 1999 for WNP-2.With 991012 Ltr ML17284A8801999-08-31031 August 1999 Monthly Operating Rept for Aug 1999 for WNP-2.With 990910 Ltr ML17284A8691999-07-31031 July 1999 Monthly Operating Rept for July 1999 for WNP-2.With 990813 Ltr ML17292B7421999-07-20020 July 1999 LER 99-001-00:on 990628,ESF Signal Closed All Eight MSIVs While Plant Was Shutdown.Caused by Failure of Relay RPS-RLY-K10D.Subject Relay Was Replaced & Tested on 990630. with 990720 Ltr ML17292B7271999-06-30030 June 1999 Monthly Operating Rept for June 1999 for WNP-2.With 990707 Ltr ML17292B6961999-05-31031 May 1999 Monthly Operating Repts for May 1999 for WNP-2.With 990608 Ltr ML17292B6641999-04-30030 April 1999 Monthly Operating Rept for Apr 1999 for WNP-2.With 990507 Ltr ML17292B6391999-03-31031 March 1999 Monthly Operating Rept for Mar 1999 for WNP-2.With 990413 Ltr ML17292B5871999-02-28028 February 1999 Monthly Operating Rept for Feb 1999 for WNP-2.With 990311 Ltr ML17292B5571999-01-31031 January 1999 Monthly Operating Rept for Jan 1999 for WNP-2.With 990210 Ltr ML17292B5621999-01-31031 January 1999 Rev 1 to COLR 98-14, WNP-2 Cycle 14 Colr. ML17292B5341999-01-15015 January 1999 Part 21 Rept Re Incorrect Modeling of BWR Lower Plenum Vol in Bison.Defect Applies Only to Reload Fuel Assemblies Currently in Operation at WNP-2.BISON Code Model for WNP-2 Has Been Revised to Correct Error ML17292B5331999-01-15015 January 1999 Part 21 Rept Re XL-S96 CPR Correlation for SVEA-96 Fuel. Defect Applies Only to WNP-2,during Cycles 12,13 & 14 Operation.Evaluations of Defect Performed by ABB-CE ML17292B4791998-12-31031 December 1998 Washington Public Power Supply Sys 1998 Annual Rept. with 981215 Ltr ML17292B5351998-12-31031 December 1998 Monthly Operating Rept for Dec 1998 for WNP-2.With 990112 Ltr ML17292B5741998-12-31031 December 1998 WNP-2 1998 Annual Operating Rept. with 990225 Ltr ML17284A8231998-11-30030 November 1998 Monthly Operating Rept for Nov 1998 for WNP-2.With 981207 Ltr ML17284A8081998-10-31031 October 1998 Monthly Operating Rept for Oct 1998 for WNP-2.With 981110 Ltr ML17292B4451998-10-27027 October 1998 LER 98-012-01:on 980715,failure to Comply with Requirements of TS SR 3.8.4.7 Was Noted.Caused by Inadequate Work Practices.Training Session Was Held with Personnel.With 981027 Ltr ML17284A7831998-09-30030 September 1998 Monthly Operating Rept for Sept 1998 for WNP-2.With 981007 Ltr ML17284A7491998-09-10010 September 1998 WNP-2 Inservice Insp Summary Rept for Refueling Outage RF13 Spring,1998. ML17284A7561998-09-0303 September 1998 LER 98-013-00:on 980805,ESF Actuations Were Noted Due to Deenergization of Vital Electrical Bus SM-8.Caused by Inadequate Direction in Troubleshooting Plan.Will Conduct Training for Engineering Personnel.With 980903 Ltr ML17284A7571998-09-0202 September 1998 LER 98-014-00:on 980807,completion of TS 3.8.1.F Required Shutdown Due to Inoperability of EDG-2 Was Noted.Caused by Degraded Voltage Regulator for DG-2.Replaced Voltage Regulator & Associated Scrs.With 980902 Ltr ML17284A7551998-09-0202 September 1998 LER 98-015-00:on 980808,discovered Reactor Coolant Pressure Boundary Leak During Shutdown Conditions.Caused by Leakage from Socket Weld (Fwb 63) on Elbow Connection.Failed Piping Connection Was Replaced.With 980902 Ltr ML17284A7681998-08-31031 August 1998 Monthly Operating Rept for Aug 1998 for WNP-2.With 980915 Ltr ML17284A7311998-08-17017 August 1998 LER 98-012-00:on 980716,determined That 24-month SR 3.8.4.7 Had Not Been Fulfilled within Specified Frequency.Caused by Inadequate Work Practices.License Requested & Received Enforcement Discretion Re Battery Svc test.W/980817 Ltr ML17284A7261998-07-31031 July 1998 Monthly Operating Rept for July 1998 for WNP-2.W/980810 Ltr ML17284A7121998-07-23023 July 1998 LER 98-006-01:on 980520,discovered Discrepancies in Low Voltage Bus Calculations During Review of 10CFR50,App R Calculations for High Impedance Faults.Caused by Inadequate Work Practices.Implemented Procedural Changes ML17284A6951998-07-17017 July 1998 LER 98-011-00:on 980617,ECCS Pump Room Flooding Was Noted Due to FP Sys Pipe Break.Caused by Inadequate Design of FP Sys.Detailed Review of FP Sys Design Was Conducted. W/980717 Ltr ML17284A6961998-07-15015 July 1998 LER 98-010-00:on 980615,TS Required Shutdown Due to Inoperability of TIP Sys Isolation Valve Was Noted.Caused by Improper Installation of TIP Tubing.Reattached Affected Tubing & Inspected Other TIP tubing.W/980715 Ltr ML17284A6731998-07-0101 July 1998 LER 98-009-00:on 980606,nuclear Steam Supply Shutoff Sys Group 3 & 4 Isolations During Testing Was Noted.Caused by Procedural Deficiency.Counseled Individuals Involved in preparation.W/980701 Ltr ML17284A6751998-06-30030 June 1998 Ro:On 980617,flooding of RB Northeast Stairwell with Consequential Flooding of Two ECCS Pump Rooms.Caused by Inadequate Fire Protection Sys Design.Pumped Out Water from Affected Areas to Point Below Berm Areas of Pump Rooms ML17284A6641998-06-24024 June 1998 LER 98-008-00:on 980531,inadvertent Full Scram During RPV Leak Testing in Mode 4 Was Noted.Caused by Change in Mgt Techniques.Revised Procedures to Take Into Account Addl Water Head in Pressure Sensing lines.W/980624 Ltr ML17284A6651998-06-24024 June 1998 LER 98-007-00:on 980530,inadvertent Full Scram & Division 1 ECCS Injection Was Noted.Caused by Failure to Meet Mgt Work Practice Expectation When Encountering Deficient Procedure. Incident Review Board Convened to Review event.W/980624 Ltr ML17284A6631998-06-19019 June 1998 LER 98-006-00:on 980520,discovered Discrepancies in Low Voltage Bus Calculations During Review of App R Calculations for High Impedance Fault Analysis.Caused Indeterminate. Implemented Procedural Changes Involving Operator Action ML17284A6551998-06-0404 June 1998 LER 98-005-00:on 980506,potential for Failure of RHR Sys Valve to Close on Isolation Signal Was Noted.Caused by Design Deficiency.Caution Tag Was Placed on RHR-V-40 Control Switch to Inform Plant Operators of limitation.W/980604 Ltr ML17284A6421998-06-0101 June 1998 LER 98-004-00:on 980502,determined That Primary Containment Penetration Overcurrent Protection Does Not Meet Reg Guide 1.63 Requirements.Caused by Inadequate Design Changes. Installed Addl Fuse in RHR-MO-9 circuit.W/980601 Ltr ML17284A6491998-05-31031 May 1998 Rev 0 to COLR 98-14, WNP-2,Cycle 14 Colr. ML17292B4031998-05-31031 May 1998 Monthly Operating Rept for May 1998 for WNP-2.W/980608 Ltr ML17292B3921998-04-30030 April 1998 Monthly Operating Rept for Apr 1998 for WNP-2.W/980513 Ltr ML17292B3291998-04-0909 April 1998 LER 98-003-00:on 980311,WNP-2 Experienced SCRAM Signal as Result of Low Rpv.Caused by Less than post-SCRAM Operational Strategy for Resetting SCRAM Signal in Conditions.Changes in post-SCRAM Operational Strategy implemented.W/980409 Ltr ML17292B3281998-04-0909 April 1998 LER 98-002-00:on 980311,reactor Scram & Plant Transient Occurred,Due to Failed Closed Main Steam Isolation Valve. Caused by Loss of Pneumatic Actuating Supply Pressure. Problem Evaluation Request Written for Failure of MS-V-22D ML17292B3371998-03-31031 March 1998 Monthly Operating Rept for Mar 1998 for WNP-2.W/980409 Ltr ML17292B2641998-03-0404 March 1998 Performance Self Assessment,WNP-2. ML17292B2661998-03-0404 March 1998 LER 98-001-00:on 980203,automatic Start of HPCS EDG Was Noted.Caused by Operator Error.Operations Crew Stabilized Plant at Approximately 75% Reactor Power & Investigation of Event Was initiated.W/980304 Ltr ML17292B2911998-02-28028 February 1998 Monthly Operating Rept for Feb 1998 for WNP-2.W/980313 Ltr ML17284A7971998-02-17017 February 1998 Rev 28 to Operational QA Program Description, WPPSS-QA-004.With Proposed Rev 29 ML17292B3591998-02-12012 February 1998 WNP-2 Cycle 14 Reload Design Rept. 1999-09-30
[Table view] |
Text
ACCELERA"+D DOCUMENT DISTRIBUTION SYSTEM ACCESSION NBR:9303120166 DOC.DATE: 93/03/08 NOTARIZED: NO DOCKET ¹ FACIL:50-397 WPPSS Nuclear Project, Unit 2, Washington Public Powe 05000397 AUTH. NAME AUTHOR AFFILIATION EADES,M.G. Washington Public Power Supply System BAKER,J.W. Washington Public Power Supply System RECIP.NAME 'ECIPIENT AFFILIATION
SUBJECT:
LER 93-006-00:on 930206,manual reactor scram initiated due to reactor recirculation pump trip while operating in area of increased awareness. Caused by component design parameter.
RRC =sys operating procedure changed.W/930308 ltr.
DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR / ENCL, / SIZE:
TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.
NOTES:"
RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL.
PD5 LA- 1 1 PD5 PD 1 1 CLIFFORD,J 1 1 INTERNAL: ACNW 2 ACRS 2 2 AEOD/DOA 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 NRR/DE/EELB 1 1 NRR/DE/EMEB 1 NRR/DORS/OEAB 1 1 NRR/DRCH/HHFBHE 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 NRR/DRIL/RPEB 1 1 NRR/DRSS/PRPB 2 NRR/ SSB/QPLB 1 1 NRR/DSSA/SRXB 1 REG FI EQ 02 1 1 RES/DSIR/EIB 1 RGN5 FILE 01 1 1 EXTERNAL: EG&G BRYCEgJ.H 2 L ST LOBBY WARD 1 1 NRC PDR 1 NSIC MURPHY,G.A 1 1 NSIC POORE,W. 1 NUDOCS FULL TXT 1 1 NOTE TO ALL"RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE! CONTACT 'I'I!I'OCUMEN I CON'I ROI. L).'k, ROOM PI-37 (EXT. 504-2065) TO ELIMINATEYOUR NAME FR')M I)IXI'RIIIUI ION LISTS FOR DOCUMENTS YOU DON'T NEED!
FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 32 ENCL 32 t
WASHINGTON PUBLIC POWER SUPPLY SYSTEM P.O. Box 968 ~ 3000 George Washington Way ~ Richland, Washington 99352 March 8, 1993 G02-93-055 Docket No. 50-397 Document Control Desk U.S. Nuclear Regulatory Commission, Washington, D.C. 20555
SUBJECT:
NUCLEAR PLANT WNP-2, OPERATING LICENSE NPF-21 LICENSEE EVENT REPORT NO.93-006 Transmitted herewith is Licensee Event Report No.93-006 for the WNP-2 Plant. This report is submitted in response to the report requirements of 10CFR50.73'and discusses the items of reportability, corrective action taken, and action taken to preclude recurrence.
Sincerely, J. W. Baker WNP-2 Plant Manager (Mail Drop 927M)
JWB/MGE/cgeh Enclosure CC: Mr. J. B. Martin, NRC - Region V Mr. R. Bar'r, NRC Resident Inspector (Mail Drop 901A, 2 Copies)
INPO Records Center - Atlanta, GA Mr. D. L. Williams, BPA (Mail Drop 399) 1200i3 9303l20ibb 93030805000397 PDR ADQCK 8 PDR
LIGENsEE Evk REPQRT (LER)
FACILITY NAME (1) DOCKET NUMB R ( ) PAGE (3)
Mashin ton Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 I OF 7 ITLE (4)
MANUALREACTOR SCRAM INITIATEDDUE TO REACTOR RECIRCULATION PUMP TRIP WHILE OPERATING IN THE AREA OF INCREASED AWARENESS EVENT DATE (5) LER NUHBER 6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8)
HONTH OAY YEAR YEAR ';. SEQUENTIAL EVI 5 ION HONTM OAY YEAR FACILITY NAMES DOCKET NUMB RS(S)
'::: NUMBER NUHBER 0 5 0 2 0 6 9 3 9 3 0 0 6 0 0 0 3 0 8 9 3 05 PERATING HIS REPORT IS SUBHITTEO PURSUANT TO THE REQUIREMENTS OF 10 CFR 5: (Check one or more of the following) (11)
ODE (9) I POWER LEVEL 20.402(b) 20.405(C) 50.73(a)(2)(iv) 77.71(b)
(10) 20.405(a)(1)(i) 50.36(c)(1) 50.73(a)(2)(v) 73.73(c) 20.405(a)(1)(ii) 50.36(c)(2) 50.73(a)(2)(vii) THER (Specify in Abstract 20.405(a)(1)(iii) 50.73(a)(2)(i) 50.73(a)(2)(viii)(A) elow and in Text, NRC 20.405(a)(1)(iv) 50.73(a)(2)(ii) 50.73(a)(2)(viii)(B) Form 366A) 20.405(a)(l)(v) 50.73(a)(2)(iii) 50.73(a)(2)(x)
LICENSEE CONTACT FOR THIS LER (12)
NAME TELEPHONE HUMBER REA CODE M. G. Eades, Licensing Engineer 5 0 9 7 7 - 4 2 7 7 COHPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)
CAUSE SYSTEM COMPONENT HAHUFACTURER EPORTABLE CAUSE SYSTEM COMPONEHT MANUFACTURER REPORTABLE 0 HPRDS TO HPRDS SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED SUBHISSION MONTH DAY YEAR ATE (15)
YES (If yes, complete EXPECTED SUBHISSION DATE) X NO TllAGT n0)
At 0947 hours0.011 days <br />0.263 hours <br />0.00157 weeks <br />3.603335e-4 months <br /> 'on February 6, 1993, control room operators at WNP-2 initiated a manual scram after the Reactor Recirculation Pump 1A (RRC-P-1A) tripped during an attempt by the operators to transfer the pump from slow speed to high speed (15 Hz to 60 Hz). During the pump shift, RRC-P-1A tripped, leaving the unit in single recirculation loop operation while operating in the Area of Increased Awareness.
A manual reactor scram is the required response to this event, in accordance with PPM 4.12.4.7, "Unintentional Entry Into the Region of Potential Core Power Instabilities".
After inserting the manual scram to exit the prohibited area, the immediate corrective action was the prompt response by the operators to bring the plant to a safe shutdown condition in accordance with approved plant procedures.
The root cause is that the risks and consequences associated with a change were not adequately reviewed or assessed. A second root cause for this event has been categorized as a component was not operated within the component design parameters in that the power level and feed flow conditions, at which the transfer to high speed was attempted were not within the acceptable parameters to satisfy to logic circuitry. As a corrective action the RRC system operating procedure was changed. Contributing factors were the operating constraints placed on the plant as a result of the power oscillation event which resulted in the RRC pump shift attempt at the lower power level.
LICENSEE EVENT REPORTER)
TEXT CONTINUATION AGILITY MANE (1) DOCKET NUMBER (2) LER NUNBER (8) PAGE (3)
Year Number ev. No.
Washington Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 3 006 00 2 OF 7 1TLE (4)
MANUAL REACTOR SCRAM INITIATED DUE TO REACTOR RECIRCULATION PUMP TRIP WHILE OPERATING IN THE AREA OF INCREASED AWARENESS
~An tact (Cont'di The event posed no threat to the health and safety of either the public or plant personnel.
Pln niin Power Level - 30%
Plant Mode - 1 Event Descri tion At 0947 hours0.011 days <br />0.263 hours <br />0.00157 weeks <br />3.603335e-4 months <br /> on February 6, 1993, control room operators at WNP-2 initiated a manual scram after the Reactor Recirculation Pump 1A (RRC-P-1A) tripped during an attempt by the operators to transfer the pump from slow speed to high speed (15 Hz to 60 Hz). At 0916 hours0.0106 days <br />0.254 hours <br />0.00151 weeks <br />3.48538e-4 months <br /> on February 6, 1993, operators in the control room at WNP-2 began the series of actions necessary to transfer the two reactor water
,recirculation system pumps from slow to high speed. This sequence of events is not initiated. until the reactor core power and control rod pattern are established as described in the Startup Plan. Reactor thermal power was 30.9%, core flow was 29%, and control rods were positioned at the target rod pattern.
The parameters place the plant in the Area of Increased Awareness, which places additional restrictions on plant operations. The Area of Increased Awareness represents a region with a relatively low probability for core power instabilities. In accordance with PPM 2.2.1, "Recirculation System Operation", the operator began closing RRC-V-60A, the flow control valve for RRC-P-1A, in incremental steps, from full open to 75%, 50%, 25% to the 0% position. Reactor feedwater system (RFW) flow indications were fluctuating as indicated on the flow recorder, RFW-FR-604B. Intermittent low feed flow signals were received as indicated by amber lights on the RRC control panel and control rod blocks were initiating and clearing
'from the Rod Block Monitors (RBM A and B). Because there is a pump shift interlock that trips the RRC pump from high speed to slow upon low feedwater flow, it was decided to return the valve to the full open position and to evaluate the situation. Review of the drawings showed that the signal to the amber light indicating the low feed flow must be in'for 15 seconds to initiate the pump shift to slow speed. That is, the instrumentation must detect the low flow condition for 15 seconds before the trip to slow speed is initiated.
Feed flow values were verified from other sources, such as the Transient Data Acquisition Computer System (TDAS), to be 3.6 E06 ibm/hr, above the low feed flow alarm/trip setpoint. The decision was made to again close RRC-V-60A and to transfer RRC-P-1A to high speed. It was also decided that if the low feed flow alarms were received during the evolution, RRC-V-60A would be reopened and a new target =
rod pattern for a higher power and higher feed flow condition would be specified. If there was no-indication of the low feed flow condition, the operators would proceed with the pump shift.
LICENSEE EVENT REPOR ER)
TEXT CONTINUATION.
AGILITY NAME (I)
OOCKET NUMBER (2)
LER NUMBER (8) AGE (3)
Year Number ev. No.
Washington Nuclear Plant - Unit 2 3 006. 00 3 F 7 ITLE (4)
MANUAL REACTOR SCRAM INITIATED DUE TO REACTOR RECIRCULATION PUMP TRIP WHILE OPERATING IN .THE AREA OF. INCREASED AWARENESS When RRC-V-60A was closed, the amber lights did not indicate low feed flow and RFW-FR-604B indicated mean feed flow value between 2.9 and 3.4 E06 Ibm/hr. The Shift Manager proceeded with the
. pump shift.
The operator took the pump start switch S101A to the start position, and held it there as he verified that breakers 1A and 2A opened and that breaker RRC-RPT-3A closed (three second time delay). (The 1A and 2A provide a power source for RRC-P-1A during slow speed operation. The breaker RRC-RPT-3A is one of the three in series for high speed operation.) As expected, the pump speed increased. Core flow increased to about 29% and reactor power increased to about 36%. However, the 3A breaker tripped at about 95% of 1800 rpm and pump speed began decreasing. The control room operators expected the pump to pick up on the Low Frequency Motor Generator (LFMG) and return to slow speed operation. At about 450 rpm, when, it became apparent the LFMG had not automatic'ally closed in, the operator attempted to manually align the pump to the LFMG. Pump speed'continued to decrease and at about 200 rpm the control room supervisor (CRS) direc'ted a manual scram due to the prohibited single loop operation in the Area of Increased Awareness.
N All control rods fully inserted and no safety relief valves actuated during the transient. Following the reactor scram, level decreased to -5 inches and increased to as high as +48 inches.
Imm ia e orrective Action Following the reactor scram, the control room operators promptly entered the Emergency Operating Procedure (EOP) 5.1.1, "RPV Power, Level, and Pressure Control", as required, when vessel level reached +13 inches following the scram. Reactor water level recovered using the reactor feed. pumps, the plant was stable and the operator exited EOP PPM 5.1.1. At 1037 hours0.012 days <br />0.288 hours <br />0.00171 weeks <br />3.945785e-4 months <br />, RRC-P-IA was restarted and operated at slow speed.
F her Eval i n an rrecive Ac i n A. Further Evaluation
- 1. In accordance with 10CFR50.72(b)(2)(ii), this event was reported to the NRC Operation Center via the Emergency Notification System at 1047 hours0.0121 days <br />0.291 hours <br />0.00173 weeks <br />3.983835e-4 months <br /> as an'unplanned manual actuation of the Reactor Protection System. This event is also reported in accordance with 10CFR50.73(a)(2)(iv) as an event that resulted in an unplanned manual actuation of the RPS.
- 2. There were no structures, components, or systems inoperable prior to this event that contributed to the event. However, a manual reactor scram was required action when the RRC-P-1A tripped.
LICENSEE EVENT REPORTER)
TEXl CONTINUATION AGILITY NAME (I) DOCKET NUMBER (2) LER NUMSER (8) AGE (3)
Year umber ev. No.
Washington Nuclear Plant - Unit 2
'0 5 0 0 0 3 9 7 3 006 00 4 OF 7 ITLE (4)
MANUAL REACTOR SCRAM INITIATED DUE TO REACTOR RECIRCULATION PUMP TRIP WHILE OPERATING IN THE AREA OF INCREASED AWARENESS
- 3. The initial post-scram investigation noted that no alarms or annunciators were received during the shift to indicate why the pump failed to transfer to high speed and tripped. The instrument that detects the low feed flow energizes a relay, K128A, and results in the down shift from high to slow speed also alarms and has an amber light on the control room panel P602. However, a different relay, C34-K10A, located in the pump start logic, changes state to direct the pump to the slow speed start logic or to the high speed start logic. There are no alarms, annunciators or other control room indications associated with this relay.
The pump start circuit is designed so that the relay C34-K10A selects the slow speed or high speed logic (see Figure 1). This relay only serves this function while the pump start switch S101A is held in the start position. Examination of the TDAS data indicated the operator held the switch in that position for about 12 seconds and that the breaker RRC-RPT-3A received the trip signal about four seconds after it closed. In order for the logic to cause this pump trip during the pump shift, the low feed flow signal must be received while the switch S101A is held in the start position, so as the time the switch is held in the start position increases the probability of receiving the spurious trip increases.
- 5. The circuitry design for transferring the pumps from slow to high speed has an unintended path resulting in tripping the 3A breaker if the attempt to shift the pumps is made at too low of a reactor power level. As installed, at a low power level as indicated by a low feed flow signal, the circuit will provide a path to seal in the logic for a slow speed start when the 3A breaker control switch S101A is held in the pump start position that causes the 3A breaker to open when the pump reaches 95% of rated speed. However, because of other components within the circuit, the actions taken to shift the pump to high speed also initiate interlocks that prevent connecting the pump to the LFMG. (The control switch for the RRC pump start is the breaker control switch for RRC-RPT-3A.) As designed, the status of the relay C34-K10A selects either the slow speed logic or the high speed logic. It was not intended, by the designer, for the shift to be attempted as near to the low flow condition as is currently required at WNP-2. The pump shift interlock to prevent high speed operation during low power and low feed flow conditions is provided with a 15 seconds time delay to avoid spurious signals resulting in pump trips.
- 6. Previous trips of the RRC pumps in similar operational conditions were prevented by bypassing the low power (i.e., low feed flow) pump start interlock with switch S118.
However, these instructions were removed from the procedure when the feed flow interlock-setpoint was lowered. The operational constraints in place in response to the core power oscillation event required the pump shifts at power levels low enough for the low feed flow signal to cause the trip of the 3A breaker and to prevent the high speed transfer. Although the pump trip had occurred in the past during-attempts to shift to high speed, procedures at that time allowed another pump start attempt or single loop operation. When the procedures
LIGENSEE EVENT REPOR ER)
TEXT CONTINUATION AC]LITY KAME (1) DOCKET NUMBER (2) LER KUMBER (8) AGE (3)
Year Number ev. Ko.
Washington Nuclear Plant - Unit 2 9
0 5 0 0 0 3 7 3 006 00 5 OF 7 ITLE (4)
MANUAL REACTOR SCRAM INITIATED DUE TO REACTOR RECIRCULATION PUMP TRIP WHILE OPERATING IN THE AREA OF INCREASED AWARENESS were revised, requiring a manual scram for single loop operation while in the Area of Increased Awareness, it was not recognized that all of these factors would combine to require a plant scram during a failed pump shift attempt due to an instantaneous low feed flow signal.
- 7. A review of the history of PPM 2.2.1, "Recirculation System Operation", revealed that, the first eight revisions did not contain instruction to bypass the low feed flow pump start during the pump shift. Revision nine was deviated on December 14, 1988, to add 'nterlock directions for bypassing them in order to eliminate spurious trips on 15 Hz to 60 Hz transfer.
The Safety Review for the deviation discussed the change as a commercial issue as opposed to a safety concern. Revision 11 (7/5/89) removed these instruction but there is not sufficient data to determine why the change was made.
B. Root Cause 1
The root cause of this event is that the risks and consequences associated with changes were not adequately reviewed or assessed. Instructions to allow bypassing the low feed flow pump start interlock while requiring a. pump shift at a low power level were removed from the system operating procedure and additional restrictions in place to prevent core oscillations required the pump shift at low power levels.
- 2. A second root cause for this event has been categorized as a component not operated within the component design parameters in that the power level and feed flow conditions, at which the transfer to high speed was attempted, were not within the acceptable parameters to satisfy to logic circuitry.
C. Further Corrective Action
- 1. The recirculation system operating procedure, PPM 2.2.1, was deviated to allow bypassing the pump start interlock C34-K10A contact during pump shift from slow to high speed.
LICENSEE EVENT REPOR ER)
TEXT CONTINUATION AGILITY NAHE (I) DOCKET NUHBER (2) LER NUHBER (8) AGE (3)
Year umber ev. No.
Washington Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 3 006 00 6 OF 7 ITLE (4)
.MANUAL REACTOR SCRAM INITIATED DUE TO REACTOR RECIRCULATION PUMP TRIP WHILE OPERATING IN THE AREA OF INCREASED AWARENESS afet i nifi n The plant operators reacted correctly in conjunction with installed plant systems to promptly bring the plant, to a safe shutdown condition, Although reactor vessel level dropped below Level 3, to -5 inches, during the transient, plant responses were well within bounds of the WNP-2 safety analyses. A manual reactor scram is the required action in response to single loop operation while the plant was in the Area of Increased Awareness in order to minimize the potential for core power oscillations. The plant was actually in the Area for a short time during single loop operation and there were no indications of oscillations during that time. During the event, the plant demonstrated the ability to respond as designed to the reactor scram. Accordingly, this event posed no threat to the safety of the public or plant personnel.
Similar Events There have been no similar events at WNP-2, in which the trip of an operating RRC pump required the manual scram of the reactor.
EII Information Tex Reference f system ~om oncet Reactor Recirculation System (RRC) AD RRC-P-lA AD- .P Reactor Protection System (RPS) IAB
- RRC Flow Control Valve FCV Reactor Feedwater System (RFW) CHA LFMG MG Relay RLY Flow Recorder FR Breaker BKR
LIOENSEE EVENT REPORTER)
TEXT CONTINUATION AGILITY NAME (I) DOCKET NUMBER (2) LER NUMBER (8) AGE (3)
Year umber ev. No.
Washingto'n Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 3 0 0 6 0 7 F 7 ITLE (4)
MANUAL REACTOR SCRAM INITIATED DUE TO REACTOR RECIRCULATION PUMP TRIP WHILE OPERATING IN THE AREA OF INCREASED AWARENESS I I Closes when FCV FOGBA Closes ot I Closes when I Low Reactor I I FCV FO68A ln I Flow Controller I Suction I Otschorge Power Level HtnlmLta POS. I In Honual Hode I I Valve Open I 'alve Open I L J I I I I I
I I I LSIB LSIB I LS
[
I I 1ntt tates I I I K II5A I
vwp S IB IA I Transfer I I
I Transfer I I
"
I K 183A I Not Complete I I
K I 13A I l I Opens ot I K138A Low Reactor I KI82A I Power Level I K128A slelA L
/ a I Low Flow
/ / //
I I K36A I
/
KI84A I /
I C31-KIBA K113A K 128A I
I C3%-K IBA K129A S I IBA S I TBA KIIBA K138A KIIIA K 132A K I I IA K112A K113A K 133A K II%A LFHG Normal to High Auto Tronsfer High Tronsfer LI4FG SET 'A'ONTROL AND 1NTERLOCK (PORTION)
FIGURE I