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Category:LICENSEE EVENT REPORT (SEE ALSO AO
MONTHYEARML18066A6271999-09-0202 September 1999 LER 98-011-01:on 981217,inadequate Lube Oil Collection Sys for Primary Coolant Pumps Was Noted.Caused by Design Change Not Containing Appropriate Level of Rigor.Exemption from 10CFR50,App R Was Requested.With 990902 Ltr ML18066A6221999-08-20020 August 1999 LER 99-002-00:on 990722,TS Surveillance Was Not Completed within Specified Frequency.Caused by Failure to Incorporate Revised Frequency Into Surveillance Schedule in Timely Manner.Verified Implementation.With 990820 Ltr ML18066A3781999-01-20020 January 1999 LER 98-013-00:on 981222,safeguards Transfer Tap Changer Failure Caused Inadvertant DG Start.Caused by Failed Motor Contactor.Contactor Was Replaced.With 990120 Ltr ML18068A4851998-10-29029 October 1998 LER 97-011-01:on 971012,starting of Primary Coolant Pump with SG Temps Greater than Cold Leg Temps Occurred.Caused by Inadequate Procedures & Operator Decision.Sop Used for Starting Primary Coolant Pump Enhanced ML18066A2831998-08-18018 August 1998 LER 98-010-00:on 980721,reactor Manually Tripped.Caused by Failure of Coupling Which Drives Feedwater Pump Main Lube Oil Pump.Main Lube Oil Pump Coupling & Associated Components Replaced & Satisfactorily Tested ML18066A2261998-06-30030 June 1998 LER 98-009-00:on 980531,small Pinhole Leak Found on One of Welds,During Leak Test Following Replacement of Pcs Sample Isolation Valves.Caused by Welder Error.Leaking Welds Repaired ML18066A1781998-06-0909 June 1998 LER 98-008-00:on 980511,noted That Procedure Did Not Fully Satisfy Requirement to Test High Startup Rate Trip Function. Caused by Misunderstanding of Testing Requirements.Revised TS Surveillance Test Procedure & Reviewed Other Procedures ML18065B2451998-05-13013 May 1998 LER 98-007-00:on 980413,HPIS Sys Was Noted Inoperable During TS Surveillance Test.Caused by Performance of Flawed Procedure.Operators & Engineers Will Be Trained to Improve Operational Decision Making Through Resources & Knowledge ML18065B1151997-12-0909 December 1997 LER 97-013-00:on 971110,failure to Closure Test Two Check Valves Resulted in Violation of TS 6.5.7 Occurred.Caused by Close Function for Check Valves.Check Valves Tested to Confirm Proper Closure Capability ML18067A7751997-11-11011 November 1997 LER 97-011-00:on 971012,primary Coolant Pump Was Started W/Sg Temperatures Greater than Cold Leg Temperature.Caused by Inadequate Procedures & Operator Decision Making.Critique of Event Conducted W/Operators Involved ML18067A7581997-10-30030 October 1997 LER 97-010-00:on 970930,determined That Inadequacy in App R Analysis Resulted in Condition Outside Design Basis of Plant.Caused by Missing Cable in Circuit & Raceway Schedule. Developed New Evaluation Re ASD Valves Validation ML18067A7461997-10-23023 October 1997 LER 97-009-00:on 970923,discovered Procedure Weakness Re Implementation of App R Shutdown Methodology.Caused by Human Error.Revised Off-Normal Procedure ONP-25.2, Alternate Safe Shutdown Procedure. ML18067A7191997-10-10010 October 1997 LER 97-008-00:on 970912,spurious Valve Operation Could Result in Loss of Shutdown Capabilities Per 10CFR50,App R, Section Iii.L,Was Discovered.Caused by Failure to Validate Info from App R.Design Bases for SW Backup Reviewed ML18067A6951997-09-24024 September 1997 LER 97-007-00:on 970826,discovered Inadequate Testing of DG Sequencer Control Relay Contacts.Caused by Oversight on Part of Personnel Involved in Installation of Facility Change FC-800.Tested 106D-1/XL & 106D-2/XL Relay Contacts ML18067A5651997-06-0303 June 1997 LER 96-013-01:on 961115,DC Breaker Failed During Testing for as-found Trip Setting.Failure Caused by Oversight within Preventive Maint Program.Breaker Was Replaced & Tested ML18067A5461997-05-12012 May 1997 LER 97-006-00:on 970412,overtime Limits Were Exceeded for Radiation Protection Technicians.Caused by Inadequate Design,Review & Proper Verifications of Overtime Work Schedule.Communicate Overtime Limitation Responsibilities ML18067A4431997-03-24024 March 1997 LER 97-004-00:on 970221,trip of High Pressure Safety Injection Pump Occurred While Filling Safety Injection Tank Resulting in TS Violation.Caused by Particle Lodged Between Surface of Indication disk.Y-phase Relay Was OOS ML18067A4391997-03-21021 March 1997 LER 97-005-00:on 961220,operation of Plant Outside Design Basis Occurred Due to an Unacceptable Repair on Main Steam Isolation Valves.Pipe Plugs Permanently Repaired ML18067A4401997-03-21021 March 1997 LER 97-003-00:on 961101,four Piping Lines Were Determined to Be Potentially Susceptible to Pressurization Due to Containment Temperature Increase During an Accident.Cac Discharge Piping Will Be verified.W/970321 Ltr ML18066A8931997-02-21021 February 1997 LER 97-002-00:on 970123,failure to Meet TSs 4.5.2d(1)(b) for Testing of Emergency Escape Airlock Occurred.Caused by Missed Surveillance.Emergency Escape Air Lock Testing Was Completed & Declared operable.W/970221 Ltr ML18066A8751997-02-0505 February 1997 LER 97-001-00:on 970106,TAVE Temp Dropped Below Minimum Temp for Criticality.Caused by Control Rod Withdrawal Rate to Increase Power Not Sufficient to Match Increase in Steam. Turbine Bypass Valve Actuator repaired.W/970205 Ltr ML18066A8041996-12-23023 December 1996 LER 96-014-00:on 961124,class 1E Raychem Cable Splices Were Installed Incorrectly.Caused by Incorrectly Made Electrical Splices.Total of 270 Splices Have Been Replaced within Containment ML18066A7831996-12-16016 December 1996 LER 96-013-00:on 961115,DC Breaker Failure During Testing for as-found Trip Setting Occurred.Cause Under Investigation.All molded-case Circuit Breakers in DC Distribution Panels Were Replaced ML18065A9951996-10-0404 October 1996 LER 96-002-01:on 960116,initiated TS Required Shutdown Due to Safeguards Cable Fault.Both Sets (Six Cables) of Cables Were Replaced & Installed Through Turbine Generator Bldg ML18065A9171996-09-0909 September 1996 LER 95-012-00:on 960809,TS Violation Occurred,Due to No Senior Reactor Operator in Cr.Caused by Extensive Remodeling.Cr Remodeling completed.W/960909 Ltr ML18065A8961996-08-29029 August 1996 LER 96-011-00:on 960730,CR Continuous Air Monitor Alarm Setpoint Improperly Established.Caused by Failure to Utilize Mod Process in 1988 Leading to Failure to Properly Select & Calibrate Instruments ML18065A8811996-08-20020 August 1996 LER 96-005-01:on 960207,determined Fuse on Main Supply to Two Safety Related DC Panels & Panel Branch Circuit Breakers Not Properly Coordinated.Caused by Lack of Thorough Associated Circuits Analysis.Supply Fuse to Panels Replaced ML18065A8741996-08-16016 August 1996 LER 96-010-00:on 960717,high Pressure Safety Injection Pump Tripped While Filling Safety Injection Tank.Caused by Faulty 150/151Y-207 Time Overcurrent Relay.All Similar Relays in Time Overcurrent Application Have Been Inspected ML18065A8651996-08-12012 August 1996 LER 96-009-00:on 960712,identified Penetration Seal Deficiency on Fire Barriers Caused by Failure to Perform & Document Comprehensive Fire Barrier Evaluation.Developed Basis document.W/960812 Ltr ML18065A8601996-08-0202 August 1996 LER 96-006-01 on 960207,discovered Limits of Design Analysis Could Have Been Violated.Subsequent Tests & Analyses Facility Did Not Exceed Basis.Operating Procedures Have Been Revised to Treat 2530 Megawatts Limit as Absolute Limit ML18065A8321996-08-0101 August 1996 LER 96-003-01:on 960115,alternate Shutdown Panel Inverter Resulted in Unavailability of Panel.Replaced Defective Inverter Alarm Logic Board ML18065A7691996-06-12012 June 1996 LER 96-008-00:on 960513,fire Door Not Maintained Open in Accordance W/Design Basis.Cause Under Investigation. Engineering Evaluation Performed & Revised Documents, Surveillance & Test procedures.W/960612 Ltr ML18065A6901996-05-0101 May 1996 LER 95-001-01:on 950302,malfunction of Left Channel DBA Sequencer Resulted in Inadvertent Actuation of Left Channel Safeguards Equipment.Replaced microprocessor.W/960501 Ltr ML18065A6681996-04-22022 April 1996 LER 96-007-00:on 960321,inadequate Emergency Lighting & Ventilation in post-fire Safe Shutdown Areas.Caused by App R Program Documentation Insufficient to Demonstrate Regulatory Compliance.Lighting modified.W/960422 Ltr ML18065A5721996-03-11011 March 1996 LER 96-006-00:on 960207,average Reactor Power Level Exceeded License Limit Due to Insufficient Procedural Guidance. GOP-12 Revised to Treat 2,530 Mwt Limit as Absolute Limit Requiring Immediate Corrective Action If Exceeded ML18065A5261996-03-0101 March 1996 LER 96-005-00:on 960202,fuse on Main Supply to Two SR DC Panels & Panel Branch Circuit Breakers Not Properly Coordinated.Caused by Inadequate Electrical/App R Design Review.Implemented Hourly Fire tours.W/960301 Ltr ML18065A5111996-02-19019 February 1996 LER 94-012-02:on 940427,determined That Internal Ground in Thermal Margin Monitor Causes Nonconformance W/Rps Design Basis.Incorporated RPS Failure Modes & Effects Analysis in Plant DBD.W/960219 Ltr ML18065A5061996-02-19019 February 1996 LER 96-004-00:on 960118,SIS Disabled W/Primary Coolant Sys Greater than 300 F.Caused by Personnel Error.Permanent Maint Procedure to Disable/Enable SIS Actuation on Low Pressurizer Pressure Will Be Revised to Align W/Ts ML18065A5021996-02-15015 February 1996 LER 96-003-00:on 960115,technicians Found Low Voltage cut- Off for Alternate Shutdown Panel Inverter Set That Resulted in Unavailability of Panel.Caused by Inadequate Post Mod. Readjusted Set Point to Minimum setting.W/960215 Ltr ML18065A4581996-01-31031 January 1996 LER 96-001-00:on 960103,failed to Test Duplicate Equipment. Caused by STS No Longer Containing Requirement for cross- Train Testing of Duplicate Components.Will Submit Request to Delete Subj Requirements from TS.W/960131 Ltr ML18065A4421996-01-19019 January 1996 LER 95-016-00:on 951226,did Not Analyze Primary Coolant Samples within 72 H.Caused by Belief Acceptability to Save Pcs Samples for Choride Analysis Past 72 H.Counseled Chemistry Supervision.W/960119 Ltr ML18065A4041996-01-15015 January 1996 LER 95-014-00:on 950119,PCP Oil Collection Deficiencies Created by FC-860 Piping Mod.Caused by Inadequate DBD for Sys & Lack of Review by Experienced Fire Protection Personnel.Updated Design Basis documentation.W/960115 Ltr ML18065A3291995-12-0404 December 1995 LER 95-013-00:on 951103,circuit Fuse Coordination Deficiency Which Affects App R Safe Shutdown Equipment Noted.Design of Fuse Coordination in Potential Transformer Circuits Will Be Evaluated & Modified as required.W/951204 Ltr ML18065A2361995-11-0202 November 1995 LER 95-012-00:on 950701,discovered Unqualified Electrical Connection in Containment SW Outlet Valve Controller.Caused by Failure of Assigned Engineers to Available Info.Replaced Wire Nuts W/Inline Butt connections.W/951102 Ltr ML18065A2051995-10-20020 October 1995 LER 95-008-01:on 950728,discovered That None of Four Containment High Pressure Channels Would Initiate Reactor Trip Due to Programmatic Deficiencies.Administrative Procedure (AP) 9.44,AP 9.45 & AP 10.44 Will Be Revised ML18065A0841995-09-18018 September 1995 LER 95-011-00:on 950817,CR 40 Withdrawal Occurred When Given Insertion Signal Due to skill-based Error in Crimping & Removing Foreign Matl from CRDM Motor Connection Box.Crd Package replaced.W/950918 Ltr ML18065A0681995-09-14014 September 1995 LER 95-010-00:on 950815,ESFA Resulted in Manual Rt Following Isolation of Pcs.Replaced Failed Instrument Line ML18065A0651995-09-0808 September 1995 LER 95-009-00:on 950728,discovered Lack of Procedural Guidance for Pump Repair Following Fire.Proposed Use of Power Supply Breaker Did Not Adequately Address Effect of Loss of Control Power.Performed Independent Assessment ML18064A8781995-08-28028 August 1995 LER 95-008-00:on 950728,discovered During Design Change Testing That None of Four Containment High Pressure Channels Would Initiate Rt.Caused by Programmatic Deficiencies. Reviewed Selected Tests & Mods from Recent Refueling Outage ML18064A8831995-08-21021 August 1995 LER 95-007-00:on 950720,discovered That 12 Instrument Loops Had V-bolted Type Qualified Cable Splices Connected to Wires W/Exposed Kapton Insulation.Caused by Human Error.All V- Bolted Splices Replaced w/in-line design.W/950821 Ltr 1999-09-02
[Table view] Category:RO)
MONTHYEARML18066A6271999-09-0202 September 1999 LER 98-011-01:on 981217,inadequate Lube Oil Collection Sys for Primary Coolant Pumps Was Noted.Caused by Design Change Not Containing Appropriate Level of Rigor.Exemption from 10CFR50,App R Was Requested.With 990902 Ltr ML18066A6221999-08-20020 August 1999 LER 99-002-00:on 990722,TS Surveillance Was Not Completed within Specified Frequency.Caused by Failure to Incorporate Revised Frequency Into Surveillance Schedule in Timely Manner.Verified Implementation.With 990820 Ltr ML18066A3781999-01-20020 January 1999 LER 98-013-00:on 981222,safeguards Transfer Tap Changer Failure Caused Inadvertant DG Start.Caused by Failed Motor Contactor.Contactor Was Replaced.With 990120 Ltr ML18068A4851998-10-29029 October 1998 LER 97-011-01:on 971012,starting of Primary Coolant Pump with SG Temps Greater than Cold Leg Temps Occurred.Caused by Inadequate Procedures & Operator Decision.Sop Used for Starting Primary Coolant Pump Enhanced ML18066A2831998-08-18018 August 1998 LER 98-010-00:on 980721,reactor Manually Tripped.Caused by Failure of Coupling Which Drives Feedwater Pump Main Lube Oil Pump.Main Lube Oil Pump Coupling & Associated Components Replaced & Satisfactorily Tested ML18066A2261998-06-30030 June 1998 LER 98-009-00:on 980531,small Pinhole Leak Found on One of Welds,During Leak Test Following Replacement of Pcs Sample Isolation Valves.Caused by Welder Error.Leaking Welds Repaired ML18066A1781998-06-0909 June 1998 LER 98-008-00:on 980511,noted That Procedure Did Not Fully Satisfy Requirement to Test High Startup Rate Trip Function. Caused by Misunderstanding of Testing Requirements.Revised TS Surveillance Test Procedure & Reviewed Other Procedures ML18065B2451998-05-13013 May 1998 LER 98-007-00:on 980413,HPIS Sys Was Noted Inoperable During TS Surveillance Test.Caused by Performance of Flawed Procedure.Operators & Engineers Will Be Trained to Improve Operational Decision Making Through Resources & Knowledge ML18065B1151997-12-0909 December 1997 LER 97-013-00:on 971110,failure to Closure Test Two Check Valves Resulted in Violation of TS 6.5.7 Occurred.Caused by Close Function for Check Valves.Check Valves Tested to Confirm Proper Closure Capability ML18067A7751997-11-11011 November 1997 LER 97-011-00:on 971012,primary Coolant Pump Was Started W/Sg Temperatures Greater than Cold Leg Temperature.Caused by Inadequate Procedures & Operator Decision Making.Critique of Event Conducted W/Operators Involved ML18067A7581997-10-30030 October 1997 LER 97-010-00:on 970930,determined That Inadequacy in App R Analysis Resulted in Condition Outside Design Basis of Plant.Caused by Missing Cable in Circuit & Raceway Schedule. Developed New Evaluation Re ASD Valves Validation ML18067A7461997-10-23023 October 1997 LER 97-009-00:on 970923,discovered Procedure Weakness Re Implementation of App R Shutdown Methodology.Caused by Human Error.Revised Off-Normal Procedure ONP-25.2, Alternate Safe Shutdown Procedure. ML18067A7191997-10-10010 October 1997 LER 97-008-00:on 970912,spurious Valve Operation Could Result in Loss of Shutdown Capabilities Per 10CFR50,App R, Section Iii.L,Was Discovered.Caused by Failure to Validate Info from App R.Design Bases for SW Backup Reviewed ML18067A6951997-09-24024 September 1997 LER 97-007-00:on 970826,discovered Inadequate Testing of DG Sequencer Control Relay Contacts.Caused by Oversight on Part of Personnel Involved in Installation of Facility Change FC-800.Tested 106D-1/XL & 106D-2/XL Relay Contacts ML18067A5651997-06-0303 June 1997 LER 96-013-01:on 961115,DC Breaker Failed During Testing for as-found Trip Setting.Failure Caused by Oversight within Preventive Maint Program.Breaker Was Replaced & Tested ML18067A5461997-05-12012 May 1997 LER 97-006-00:on 970412,overtime Limits Were Exceeded for Radiation Protection Technicians.Caused by Inadequate Design,Review & Proper Verifications of Overtime Work Schedule.Communicate Overtime Limitation Responsibilities ML18067A4431997-03-24024 March 1997 LER 97-004-00:on 970221,trip of High Pressure Safety Injection Pump Occurred While Filling Safety Injection Tank Resulting in TS Violation.Caused by Particle Lodged Between Surface of Indication disk.Y-phase Relay Was OOS ML18067A4391997-03-21021 March 1997 LER 97-005-00:on 961220,operation of Plant Outside Design Basis Occurred Due to an Unacceptable Repair on Main Steam Isolation Valves.Pipe Plugs Permanently Repaired ML18067A4401997-03-21021 March 1997 LER 97-003-00:on 961101,four Piping Lines Were Determined to Be Potentially Susceptible to Pressurization Due to Containment Temperature Increase During an Accident.Cac Discharge Piping Will Be verified.W/970321 Ltr ML18066A8931997-02-21021 February 1997 LER 97-002-00:on 970123,failure to Meet TSs 4.5.2d(1)(b) for Testing of Emergency Escape Airlock Occurred.Caused by Missed Surveillance.Emergency Escape Air Lock Testing Was Completed & Declared operable.W/970221 Ltr ML18066A8751997-02-0505 February 1997 LER 97-001-00:on 970106,TAVE Temp Dropped Below Minimum Temp for Criticality.Caused by Control Rod Withdrawal Rate to Increase Power Not Sufficient to Match Increase in Steam. Turbine Bypass Valve Actuator repaired.W/970205 Ltr ML18066A8041996-12-23023 December 1996 LER 96-014-00:on 961124,class 1E Raychem Cable Splices Were Installed Incorrectly.Caused by Incorrectly Made Electrical Splices.Total of 270 Splices Have Been Replaced within Containment ML18066A7831996-12-16016 December 1996 LER 96-013-00:on 961115,DC Breaker Failure During Testing for as-found Trip Setting Occurred.Cause Under Investigation.All molded-case Circuit Breakers in DC Distribution Panels Were Replaced ML18065A9951996-10-0404 October 1996 LER 96-002-01:on 960116,initiated TS Required Shutdown Due to Safeguards Cable Fault.Both Sets (Six Cables) of Cables Were Replaced & Installed Through Turbine Generator Bldg ML18065A9171996-09-0909 September 1996 LER 95-012-00:on 960809,TS Violation Occurred,Due to No Senior Reactor Operator in Cr.Caused by Extensive Remodeling.Cr Remodeling completed.W/960909 Ltr ML18065A8961996-08-29029 August 1996 LER 96-011-00:on 960730,CR Continuous Air Monitor Alarm Setpoint Improperly Established.Caused by Failure to Utilize Mod Process in 1988 Leading to Failure to Properly Select & Calibrate Instruments ML18065A8811996-08-20020 August 1996 LER 96-005-01:on 960207,determined Fuse on Main Supply to Two Safety Related DC Panels & Panel Branch Circuit Breakers Not Properly Coordinated.Caused by Lack of Thorough Associated Circuits Analysis.Supply Fuse to Panels Replaced ML18065A8741996-08-16016 August 1996 LER 96-010-00:on 960717,high Pressure Safety Injection Pump Tripped While Filling Safety Injection Tank.Caused by Faulty 150/151Y-207 Time Overcurrent Relay.All Similar Relays in Time Overcurrent Application Have Been Inspected ML18065A8651996-08-12012 August 1996 LER 96-009-00:on 960712,identified Penetration Seal Deficiency on Fire Barriers Caused by Failure to Perform & Document Comprehensive Fire Barrier Evaluation.Developed Basis document.W/960812 Ltr ML18065A8601996-08-0202 August 1996 LER 96-006-01 on 960207,discovered Limits of Design Analysis Could Have Been Violated.Subsequent Tests & Analyses Facility Did Not Exceed Basis.Operating Procedures Have Been Revised to Treat 2530 Megawatts Limit as Absolute Limit ML18065A8321996-08-0101 August 1996 LER 96-003-01:on 960115,alternate Shutdown Panel Inverter Resulted in Unavailability of Panel.Replaced Defective Inverter Alarm Logic Board ML18065A7691996-06-12012 June 1996 LER 96-008-00:on 960513,fire Door Not Maintained Open in Accordance W/Design Basis.Cause Under Investigation. Engineering Evaluation Performed & Revised Documents, Surveillance & Test procedures.W/960612 Ltr ML18065A6901996-05-0101 May 1996 LER 95-001-01:on 950302,malfunction of Left Channel DBA Sequencer Resulted in Inadvertent Actuation of Left Channel Safeguards Equipment.Replaced microprocessor.W/960501 Ltr ML18065A6681996-04-22022 April 1996 LER 96-007-00:on 960321,inadequate Emergency Lighting & Ventilation in post-fire Safe Shutdown Areas.Caused by App R Program Documentation Insufficient to Demonstrate Regulatory Compliance.Lighting modified.W/960422 Ltr ML18065A5721996-03-11011 March 1996 LER 96-006-00:on 960207,average Reactor Power Level Exceeded License Limit Due to Insufficient Procedural Guidance. GOP-12 Revised to Treat 2,530 Mwt Limit as Absolute Limit Requiring Immediate Corrective Action If Exceeded ML18065A5261996-03-0101 March 1996 LER 96-005-00:on 960202,fuse on Main Supply to Two SR DC Panels & Panel Branch Circuit Breakers Not Properly Coordinated.Caused by Inadequate Electrical/App R Design Review.Implemented Hourly Fire tours.W/960301 Ltr ML18065A5111996-02-19019 February 1996 LER 94-012-02:on 940427,determined That Internal Ground in Thermal Margin Monitor Causes Nonconformance W/Rps Design Basis.Incorporated RPS Failure Modes & Effects Analysis in Plant DBD.W/960219 Ltr ML18065A5061996-02-19019 February 1996 LER 96-004-00:on 960118,SIS Disabled W/Primary Coolant Sys Greater than 300 F.Caused by Personnel Error.Permanent Maint Procedure to Disable/Enable SIS Actuation on Low Pressurizer Pressure Will Be Revised to Align W/Ts ML18065A5021996-02-15015 February 1996 LER 96-003-00:on 960115,technicians Found Low Voltage cut- Off for Alternate Shutdown Panel Inverter Set That Resulted in Unavailability of Panel.Caused by Inadequate Post Mod. Readjusted Set Point to Minimum setting.W/960215 Ltr ML18065A4581996-01-31031 January 1996 LER 96-001-00:on 960103,failed to Test Duplicate Equipment. Caused by STS No Longer Containing Requirement for cross- Train Testing of Duplicate Components.Will Submit Request to Delete Subj Requirements from TS.W/960131 Ltr ML18065A4421996-01-19019 January 1996 LER 95-016-00:on 951226,did Not Analyze Primary Coolant Samples within 72 H.Caused by Belief Acceptability to Save Pcs Samples for Choride Analysis Past 72 H.Counseled Chemistry Supervision.W/960119 Ltr ML18065A4041996-01-15015 January 1996 LER 95-014-00:on 950119,PCP Oil Collection Deficiencies Created by FC-860 Piping Mod.Caused by Inadequate DBD for Sys & Lack of Review by Experienced Fire Protection Personnel.Updated Design Basis documentation.W/960115 Ltr ML18065A3291995-12-0404 December 1995 LER 95-013-00:on 951103,circuit Fuse Coordination Deficiency Which Affects App R Safe Shutdown Equipment Noted.Design of Fuse Coordination in Potential Transformer Circuits Will Be Evaluated & Modified as required.W/951204 Ltr ML18065A2361995-11-0202 November 1995 LER 95-012-00:on 950701,discovered Unqualified Electrical Connection in Containment SW Outlet Valve Controller.Caused by Failure of Assigned Engineers to Available Info.Replaced Wire Nuts W/Inline Butt connections.W/951102 Ltr ML18065A2051995-10-20020 October 1995 LER 95-008-01:on 950728,discovered That None of Four Containment High Pressure Channels Would Initiate Reactor Trip Due to Programmatic Deficiencies.Administrative Procedure (AP) 9.44,AP 9.45 & AP 10.44 Will Be Revised ML18065A0841995-09-18018 September 1995 LER 95-011-00:on 950817,CR 40 Withdrawal Occurred When Given Insertion Signal Due to skill-based Error in Crimping & Removing Foreign Matl from CRDM Motor Connection Box.Crd Package replaced.W/950918 Ltr ML18065A0681995-09-14014 September 1995 LER 95-010-00:on 950815,ESFA Resulted in Manual Rt Following Isolation of Pcs.Replaced Failed Instrument Line ML18065A0651995-09-0808 September 1995 LER 95-009-00:on 950728,discovered Lack of Procedural Guidance for Pump Repair Following Fire.Proposed Use of Power Supply Breaker Did Not Adequately Address Effect of Loss of Control Power.Performed Independent Assessment ML18064A8781995-08-28028 August 1995 LER 95-008-00:on 950728,discovered During Design Change Testing That None of Four Containment High Pressure Channels Would Initiate Rt.Caused by Programmatic Deficiencies. Reviewed Selected Tests & Mods from Recent Refueling Outage ML18064A8831995-08-21021 August 1995 LER 95-007-00:on 950720,discovered That 12 Instrument Loops Had V-bolted Type Qualified Cable Splices Connected to Wires W/Exposed Kapton Insulation.Caused by Human Error.All V- Bolted Splices Replaced w/in-line design.W/950821 Ltr 1999-09-02
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML18066A6901999-11-0101 November 1999 Rev 5 to Palisades Nuclear Plant Colr. ML18066A6761999-09-30030 September 1999 Monthly Operating Rept for Sept 1999 for Palisades Nuclear Plant ML18066A6271999-09-0202 September 1999 LER 98-011-01:on 981217,inadequate Lube Oil Collection Sys for Primary Coolant Pumps Was Noted.Caused by Design Change Not Containing Appropriate Level of Rigor.Exemption from 10CFR50,App R Was Requested.With 990902 Ltr ML18066A6351999-08-31031 August 1999 Monthly Operating Rept for Aug 1999 for Palisades Nuclear Plant ML18066A6771999-08-31031 August 1999 Operating Data Rept Page of MOR for Aug 1999 for Palisades Nuclear Plant ML18066A6221999-08-20020 August 1999 LER 99-002-00:on 990722,TS Surveillance Was Not Completed within Specified Frequency.Caused by Failure to Incorporate Revised Frequency Into Surveillance Schedule in Timely Manner.Verified Implementation.With 990820 Ltr ML18066A6061999-07-31031 July 1999 Monthly Operating Rept for July 1999 for Palisades Nuclear Plant.With 990803 Ltr ML18066A5201999-06-30030 June 1999 Monthly Operating Rept for June 1999 for Palisades Nuclear Plant.With 990702 Ltr ML18066A4841999-05-31031 May 1999 Monthly Operating Rept for May 1999 for Palisades Nuclear Plant.With 990603 Ltr ML18066A6371999-04-30030 April 1999 Revised Monthly Operating Rept for Apr 1999 for Palisades Nuclear Plant ML18068A5941999-04-30030 April 1999 Monthly Operating Rept for Apr 1999 for Palisades Nuclear Plant.With 990503 Ltr ML18066A4161999-04-0101 April 1999 Rev 4 to COLR, for Palisades Nuclear Plant ML18066A4501999-03-31031 March 1999 Monthly Operating Rept for Mar 1999 for Palisades Nuclear Plant.With 990402 Ltr ML18066A4671999-03-31031 March 1999 Rev 0 to SIR-99-032, Flaw Tolerance & Leakage Evaluation Spent Fuel Pool Heat Exchanger E-53B Nozzle Palisades Nuclear Plant. ML18068A5351999-02-28028 February 1999 Monthly Operating Rept for Feb 1999 for Palisades Nuclear Plant.With 990302 Ltr ML18066A3931999-01-31031 January 1999 Monthly Operating Rept for Jan 1999 for Palisades Nuclear Plant.With 990202 Ltr ML18066A3781999-01-20020 January 1999 LER 98-013-00:on 981222,safeguards Transfer Tap Changer Failure Caused Inadvertant DG Start.Caused by Failed Motor Contactor.Contactor Was Replaced.With 990120 Ltr ML20206F6131998-12-31031 December 1998 1998 Consumers Energy Co Annual Rept. with ML18066A3651998-12-31031 December 1998 Monthly Operating Rept for Dec 1998 for Palisades Nuclear Plant.With 990105 Ltr ML18066A3421998-11-30030 November 1998 Monthly Operating Rept for Nov 1998 for Palisades Nuclear Plant.With 981202 Ltr ML18066A3301998-11-11011 November 1998 Part 21 Rept Re Potential Safety Hazard Associated with Wrist Pin Assemblies for FM-Alco 251 Engines at Palisades Nuclear Power Plant.Caused by Insufficient Friction Fit Between Pin & Sleeve.Supplier of Pin Will No Longer Be Used ML18068A4921998-10-31031 October 1998 Monthly Operating Rept for Oct 1998 for Palisades Nuclear Plant.With 981103 Ltr ML18068A4851998-10-29029 October 1998 LER 97-011-01:on 971012,starting of Primary Coolant Pump with SG Temps Greater than Cold Leg Temps Occurred.Caused by Inadequate Procedures & Operator Decision.Sop Used for Starting Primary Coolant Pump Enhanced ML18066A3181998-09-30030 September 1998 Monthly Operating Rept for Sept 1998 for Palisades Nuclear Plant ML18066A2901998-08-31031 August 1998 Monthly Operating Rept for Aug 1998 for Palisades Nuclear Power Plant.With 980903 Ltr ML18066A3191998-08-31031 August 1998 Revised Monthly Operating Rept Data for Aug 1998 for Palisades Nuclear Plant ML18066A2831998-08-18018 August 1998 LER 98-010-00:on 980721,reactor Manually Tripped.Caused by Failure of Coupling Which Drives Feedwater Pump Main Lube Oil Pump.Main Lube Oil Pump Coupling & Associated Components Replaced & Satisfactorily Tested 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 ML20237E0301998-07-31031 July 1998 ISI Rept 3-3 ML18066A2701998-07-31031 July 1998 Monthly Operating Rept for July 1998 for Palisades Nuclear Plant.W/980803 Ltr ML18066A2311998-06-30030 June 1998 Monthly Operating Rept for June 1998 for Palisades Nuclear Plant ML18066A2261998-06-30030 June 1998 LER 98-009-00:on 980531,small Pinhole Leak Found on One of Welds,During Leak Test Following Replacement of Pcs Sample Isolation Valves.Caused by Welder Error.Leaking Welds Repaired ML18066A3061998-06-18018 June 1998 SG Tube Inservice Insp. ML20249C4951998-06-17017 June 1998 Rev 1 to EA-GEJ-98-01, Palisades Cycle 14 Disposition of Events Review ML18066A1781998-06-0909 June 1998 LER 98-008-00:on 980511,noted That Procedure Did Not Fully Satisfy Requirement to Test High Startup Rate Trip Function. Caused by Misunderstanding of Testing Requirements.Revised TS Surveillance Test Procedure & Reviewed Other Procedures ML18066A1711998-06-0101 June 1998 Part 21 Rept Re Impact of RELAP4 Excessive Variability on Palisades Large Break LOCA ECCS Results.Change in PCT Between Cycle 13 & Cycle 14 Does Not Constitute Significant Change Per 10CFR50.46 ML18066A1741998-05-31031 May 1998 Monthly Operating Rept for May 1998 for Palisades Nuclear Plant.W/980601 Ltr ML18066A2321998-05-31031 May 1998 Revised MOR for May 1998 for Palisades Nuclear Plant ML18068A4701998-05-31031 May 1998 Annual Rept of Changes in ECCS Models Per 10CFR50.46. ML18065B2451998-05-13013 May 1998 LER 98-007-00:on 980413,HPIS Sys Was Noted Inoperable During TS Surveillance Test.Caused by Performance of Flawed Procedure.Operators & Engineers Will Be Trained to Improve Operational Decision Making Through Resources & Knowledge ML18066A2331998-04-30030 April 1998 Revised MOR for Apr 1998 for Palisades Nuclear Plant ML18068A3461998-04-30030 April 1998 Monthly Operating Rept for Apr 1998 for Palisades Nuclear Plant.W/980501 Ltr ML18066A3411998-04-22022 April 1998 Rev 0 to EMF-98-013, Palisades Cycle 14:Disposition & Analysis of SRP Chapter 15 Events. ML18065B2071998-03-31031 March 1998 Monthly Operating Rept for Mar 1998 for Palisades Nuclear Plant.W/980403 Ltr ML20217C2741998-03-31031 March 1998 Independent Review - Is Consumers Energy Method (W Method) of Determining Palisades Nuclear Plant Best Estimate Fluence by Combining Transport Calculation & Dosimetry Measurements Technically Sound & Does It Meet Intent of Pts ML18066A2341998-03-31031 March 1998 Revised MOR for Mar 1998 for Palisades Nuclear Plant ML18068A3041998-02-28028 February 1998 Monthly Operating Rept for Feb 1998 for Palisades Nuclear Plant.W/980302 Ltr ML18066A2351998-02-28028 February 1998 Revised MOR for Feb 1998 for Palisades Nuclear Plant ML18065B1641998-02-0505 February 1998 Rev 0 to Regression Analysis for Containment Prestressing Sys at 25th Year Surveillance. ML18067A8211998-01-31031 January 1998 Monthly Operating Rept for Jan 1998 for Palisades Nuclear Plant.W/980203 Ltr 1999-09-30
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consumers Power KurtM. Haas Plant Safety and Licensing Director POWERING lllllClllGAN"S PROGRESS Palisades Nuclear Plant: 27780 Blue Star Memorial Highway, Covert, Ml 49043 December 28, 1994
, Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT LICENSEE EVENT REPORT 94-004 ESS PUMP COOLING SINGLE FAILURE -
SUPPLEMENTAL REPORT Licensee Event Report (LER} 94-004-01 is attached. This supplemental report provides the final evaluation of the safety significance that a loss of cooling
- to the ESS room pumps would have on the pumps post accident operability~
This event was originally reported in accordance with 10CFR50.73(a}(2}(ii}(B} as a condition outside the design basis.
SUMMARY
OF COMMITMENTS This LER contains one new commitment, as follows~
The FSAR will be updated to clarify the requirements for.ESS pump cooling and also the requirement to use the "subcooled suction" flow path for the HPSI pumps.
Kurt MHaas Plant Safety and Licensing Director CC Administrator, Region III, USNRC NRC Resident Inspector - Palisades Attachment 9501050241 9'1-1228 F'DR ADDCK 05000255 s PDR A CM5 ENERGY COMPANY
\...I NRC Form 366 U.S. NUCLEAR REGULATORY COMMISSION (9-831 APPROVED OMB NO. 3160-0104 EXPIRES: B/31 /86 LICENSEE EVENT REPORT (LERI FACILITY NAME 111 DOCKET NUMBER 121 PAGE 131 Palisades Plant 0 5 0 0 0 2 5 5 OF 0 5 Tine 141 LICENSEE EVENT REPORT 94-004 ESS PUMP COOLING SINGLE FAILURE EVENT DATE 161 LER NUMBER (SI REPORT DATE ISi OTHER FACILITIES INVOLVED 181 REVISION FACILITY NAMES MONTH DAY YEAR YEAR NUMBER MONTH DAY YEAR N/A 0 6 0 0 0 0 2 0 9 9 4 9 4 0 0 4 0 1 2 2 9 4 N/A 0 & 0 0 0 THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR I: (Ch<<lc OM,,,,,_. of tlN following/ 1111 OPERATING N ..,....T"""2-o-.40-2-~-1-------------r--r-----------------r-,-----------------"T"""-.--13-.1-1-1b-1-------------4 20.40&1cl 60. 7 31*112Wvl MODE (91 20.40&1*111llil &0.3Blcll1 I &0.731*1121M 73.71(cl 20.40&1all11fiil &0.3Blcll21 &0.731*11211viil OTHER !Specify In Abstract 20.406(*111 )(iiil &0.731*1121111 &0.731*11211viiil1AI below and in Text, 20.4061*111 IPvl x &0.731*112lliil &0.73(all211viiillBI NRC Form 3BBAI 20.40&1*1111M &0.731*1121foiil 60. 7 3(a)(2)(xl LICENSEE CONTACT FOR THIS LER (121 NAME TELEPHONE NUMBER AREA CODE William L. Roberts, Staff Licensing Engineer 6 6 7 6 4 8 9 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (131 t----r-----r----------~-------------,--------~~ -----,i------,.-----------r-----------r-------....,,,,.,,,,,,"""'
MANUFAC- REPORTABLE MANUFAC* REPORTABLE CAUSE SYSTEM COMPONENT TURER TONPRDS CAUSE SYSTEM COMPONENT TURER TO NPRDS SUPPLEMENTAL REPORT EXPECTED (141 MONTH DAY YEAR EXPECTED SUBMISSION YES Uf yH, complete EXPECTED SUBMISSION DATE! NO DATE (161 ABSTRACT UimJt to 1400 IP<<*&. I.e., epptOJtimllre/y fiftHn 6in(11e-1P<<* typewrlrren line.ti (1 Bl On February 9, 1994, at 5:45 pm, while the plant was operating at 100% power, a previously unidentified single failure mechanism which could affect the Engineered Safeguards System (ESS) pumps was discovered. It was discovered that a single active failure could disable the seal cooling to the ESS pumps and that the backup cooling supply was not fully qualified. An initial evaluation of the plant condition and of the effects of the potential failure mechanism concluded that the operability of the pumps was not affected.
As an immediate corrective action, the normally closed pump cooling valves were opened to .I eliminate the possibility of the subject single failure, their failing to open. The plant remained at power. Subsequent analysis determined that post accident loss of cooling water to the ESS I pumps may have resulted in the pumps not being able to perform their design basis function. I **
NRC Form 388A U.S. NUCLEAR REGULATORY COMMISSION (9*83) APPROVED OMB NO. 3160-0104 EXPIRES: 8/31 /86 LICENSEE EVENT REPORT (LERI TEXT CONTINUATION FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (3) PAGE (41 SEQUENTIAL REVISION YEAR NUMBER NUMBER Palisades Plant 0 I6 I0 I0 I0 I 2 I6 I 5 9 I4 - 0 I0 I 4 - 0 I1 0 I2 OF 0 I6 EVENT DESCRIPTION On February 9, 1994, at 5:45 pm, while the plant was operating at 100% power, a previously unidentified single failure mechanism which could affect the Engineered Safeguards System (ESS) pumps was discovered. It was discovered that a single active failure could disable the seal cooling to the ESS pumps and that the backup cooling supply was not fully qualified. An evaluation of the plant condition and of the effects of the potential failure mechanism concluded that the operability of the pumps was not affected.
The affected valves were opened to eliminate the possibility of the subject singl~ failure, their failing to open. The plant remained at power.
This event is reportable in accordance with 10CFR50.73(a)(2)(ii)(8) as a condition outside the design basis.
CAUSE OF THE EVENT The cause of this event was the failure to recognize that the ESS pumps are dependent on seal and bearing cooling and that this dependence was outside the plant de~ign basis.
ANALYSIS OF THE EVENT The Palisades Engineered Safeguards Systems (ESS) pumps are equipped witt:i seal and bearing cooling. The initial design, as currently understood, considered the seal and bearing cooling as an optional function intended to extend pump bearing and seal life. Subsequent correspondence with the equipment vendors has determined that pump cooling is required for the long term operability of the pumps. This is a condition outside the plant design basis.
ESS pump cooling is provided by: diverting a small portion of each pump's discharge flow through a heat exchanger, where it is cooled by Component Cooling Water (CCW); directing it through cooling jackets around the pump's seal areas; and then returning it to the pump suction. CCW is also directed to cooling jackets around the pump bearing areas. The CCW flow for all pump cooling is controlled by common supply and return valves, CV-0913 and CV-0950. (The Palisades CCW system has redundant trains of pumps and pump controls, but uses a single, common, piping system.) These two valves are opened automatically on a Safety Injection Signal (SIS). A backup cooling supply is available, through non-automatic valves, from the Service Water System (SWS). A sketch of the pertinent portions of the piping systems is attached.
The normal configuration for the CCW to the pump seal cooling had been for both CV-0913 and CV-0950 to be closed. Both of these valves are spring loaded to the open position, requiring
NRC Form 3BBA U.S. NUCLEAR REGULATORY COMMISSION 19-831 APPROVED OMB NO. 3160-0104 EXPIRES: 8/31 /86 LICENSEE EVENT REPORT (LERI TEXT CONTINUATION FACILITY NAME 111 DOCKET NUMBER 121 LER NUMBER 131 PAGE 141 SEQUENTIAL REVISION YEAR NUMBER NUMBER Palisades Plant 0 I6 I0 I0 I0 I2 I6 I6 9 I4 - 0 I0 I 4 - 0 I1 0 I3 OF 0 I6 availability of both instrument air and electrical power to hold them closed. The valves which supply the SWS backup cooling are also normally closed, but are spring loaded to the closed position, requiring availability of both instrument air and electrical power to open them.
If, following a Loss Of Coolant Accident (LOCA), either CV-0913 or CV-0950 failed to open*on demand (possibly due to binding of the valve stem or similar failure) cooling flow to the ESS pumps would not be available from the CCW system. Conceptually, recovery from such a failure would simply require the operators to initiate the alternate cooling by closing the open CCW valve and opening the SWS valves. Palisades design features complicate this recovery; instrument air is not a safety grade system and thereby might not be available. These conditions lead to the possibility of a single active failure disabling the ESS pumps.
The use of non-safety grade instrument air to open the backup cooling implies that credit should not be taken, in the design basis, for operation of backup cooling. Therefore, if either CV-0913 or CV-0950 should fail to open on demand, all (safety grade) cooling to the ESS pumps, and consequently the functioning of the pumps themselves, could eventually be lost.
There are three types of ESS pumps used at Palisades, Containment Spray (CS), High Pressure Safety Injection (HPSI), and Low Pressure Safety Injection (LPSI).
- In the FSAR descriptions of
.both the HPSI and the LPSI pumps, the seal coolers are described as being supplied "to prolong seal life"; the FSAR description of the CS pumps makes no mention of*the seal cooling at all.
The statement "to prolong seal life" has typically been taken. to mean that the pumps would survive their required accident duties without cooling, but cooling was provided to reduce maintenance due to normal wear. The safety injection pumps were supplied by Combustion Engineering; the containment spray pumps by Bechtel. The system designers and, probably, the writers of the FSAR descriptions were different. An evaluation of ESS pump and seal performance and cooling dependence was performed. *Each pump type is discussed below:
- 1) The CS pumps are single stage centrifugal pumps. The original quotation from the vendor stated "Should there be a stoppage of cooling water, the only damage would occur to the pump seal." Subsequent correspondence with the vendor, discussing pump operation with 325°F water, states that operation without cooling could quickly lead to seal failure, and questioned the effects on bearing life. Consequently, cooling water is required for operation of the CS pumps.
- 2) The HPSI pumps are seven stage centrifugal pumps. The HPSI pump seal manufacturer has supplied data that state the pump seals can function properly, with no cooling, while pumping 300°F water. The HPSI pump vendor approved bearing operation with no cooling, while pumping 250°F water. Both the pump and seal vendors do, however, recommend cooling water be provided to extend pump and seal life. The highest temperature water the HPSI pumps would encounter would be that at the initiation of recirculation. Existing analysis which calculate sump temperatures were done to bound the conditions following
NRC Form 388A U.S. NUCLEAR REGULATORY COMMISSION 19-831 APPROVED OMB NO. 3160-0104 EXPIRES: 8/31 /86 LICENSEE EVENT REPORT (LERI TEXT CONTINUATION FACILITY NAME 111 DOCKET NUMBER 121 LER NUMBER 131 PAGE 141 SEQUENTIAL REVISION YEAR NUMBER NUMBER Palisades Plant 0 I5 I0 I0 I0 I2 I5 I5 9 I4 - 0 I0 I 4 - 0 I1 0 I4 OF 0 I5 an accident, and assume the complete failure of one train of safeguards equipment. The highest analytical sump temperature at the time of recirculation, 235.5°F, is found. in the analyses which assumes failure of the right train. The HPSI pumps, therefore, would not be directly affected by a loss of cooling.
The HPSI pumps do, however, have a dependence on the CS pumps. A manually controlled suction path from the discharge of the cs pumps, through the shutdown cooling heat exchangers, to the suction of the HPSI pumps was provided as part of the original Palisades design. Use of this suction path can boost the net positive suction head of the HPSI pumps by raising the suction pressure. The FSAR states that use 'of this "sub-cooled suction" path .is not required for pump operation. Subsequent engineering evaluations have led to questioning of this statement. It is currently believed that the increase in pressure from use of the sub-cooled suction is necessary to maintain adequate NPSH for the HPSI pumps during particularly high flow portions of the post-LOCA recirculation phase. Current operating procedures direct the operators to align the HPSI pumps to utilize the sub-cooled suction path following initiation of recirculation. This reliance upon the sub-cooled suction paths for HPSI operation is not in conformance with the plant design, as presented in the FSAR. It is this dependance, on the sub-cooled suction from the CS pump discharge, which also makes the HPSI pumps indirectly dependant on seal and bearing cooling.
- 3) The LPSI pumps are single stage centrifugal pumps. They are not affected, during accident scenarios, by a loss of seal and bearing cooling since they are automatically tripped on initiation of recirculation.
The LPSI pumps are used, however, for shutdown cooling (decay heat removal) service, where pumped fluid temperature can be as high as 300°F. Provision is also made in the design to bypass the LPSI pump trip on recirculation initiation, or to restart them after initiation of recirculation. The FSAR states that the seals are designed for operation at 325°F. Subsequent correspondence with the vendor, discussing pump operation with 325°F water decreasing to 130°F, states that operation without cooling in either continuous or intermittent duty is not recommended. Consequently, cooling water is required for operation of the LPSI pumps.
SAFETY SIGNIFICANCE Common mode failure of the ESS pumps due to a loss of cooling water is of considerable safety significance. The probability of such a failure due to the subject single failure is judged to be quite low. The two valves involved are both "fail open" valves, meaning that if instrument air pressure or electrical power to the valves were lost, they would stroke to their open (safety) position. Proper operation of these valves is verified quarterly. The action taken, to operate with both of the subject valves in their open position, removes the potential for their failing to
l.
.J rN~RC~F~<<-m-38-SA-------------------1 U.S. NUCLEAR REGULATORY COMMISSION
{,* 19-831 APPROVED OMB NO. 3160-0104 EXPIRES: 8/31 /86 f LICENSEE EVENT REPORT (LERI TEXT CONTINUATION
.FACILITY NAME 11' DOCKET NUMBER 121 LER NUMBER 131 PAGE 141 SEQUENTIAL REVISION YEAR NUMBER NUMBER Palisades Plant 0 I5 I0 I0 I0 I2 I5 I5 9 I4 - 0 I0 I 4 - 0 I1 0 I5 OF 0 I5 open on demand.
A re-evaluation of the ESF pump cooling requirements was completed. It was thought that a re-evaluation might show that the ESF pumps required no cooling to perform their design basis function. The original calculations for ESF pump cooling used very conservative inputs such as a containment sump water temperature equivalent to the peak containment LOCA _temperature.
The results of the re-analysis determined that the ES-F pumps would still, however, require some amount of post accident cooling water flow.
Therefore, a loss of cooling water to the ESF pumps following a LOCA, may have resulted in the ESF pumps not being able to perform their design basis function for the time required.
CORRECTIVE ACTION
- 1) Immediate action was taken to revise the plant operating procedures so that the normal position for both CV-0913 and CV-0950 is "OPEN", and to place the valves in that position. Since the valves are spring operated to the open position, and require both instrument air and electrical power to close them, this action eliminates the potential for a single active failure disabling the ESS pumps due to the subject failure.
- 2) An assessment was made of the interim valve alignment for the CCW cooling to the engineered safeguards pumps (CV-0913 and CV-0950 open) to verify that the alignment meets plant design and licensing requirements and serves to minimize plant risk. The I results of the assessment determined that operating with the CCW valves normally open I *-
meets plant design and licensing requirements and will reduce the overall plant risk I compared with having the CCW valves normally closed. I
- 3) A re-evaluation of the ESF pump cooling *requirements was completed. The evaluation I concluded that cooling water is required. The FSAR will be updated to clarify the I requirements for ESF pump cooling and also the requirement to use the "subcooled I Suction" flow path for the HPSI pumps. I
- 4) An action was completed. to confirm the need to provide sub~cooled suction (from the I containment Spray pumps) to the HPSI pumps following RAS. If such an operation is not I required, the seal cooling and bearing cooling water requirements for the containment spray _I pumps may have been reduced since their required post accident mission time would be I reduced. The results of the evaluation determined that sub-cooling of the HPSI pump I suction is necessary to assure HPSI pump NPSH following RAS. Consequently, no I reduction in containment spray pump mission time can be justified. I
- 5) Perform a design review of the CCW and SWS systems, including a single failure analysis 1-of the systems.