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Category:LICENSEE EVENT REPORT (SEE ALSO AO
MONTHYEARML20024B7371983-07-0505 July 1983 LER 83-011/03L-0:on 830605,circuit Breaker for Boron Injection Tank Heater Channel B Tripped.Caused by Component Failure Due to Normal End of Life.Failed Heater Replaced. W/830705 Ltr ML20023E0791983-05-27027 May 1983 LER 83-007/03L-0:on 830429,PORV RC-455C Failed to Meet Required Cycle Time & Failed to Open Fully on Subsequent Attempt.Caused by Galling of Valve Plug to Cage Due to Rubbing of Stainless Steel in Dry condition.W/830527 Ltr ML20023E0671983-05-26026 May 1983 LER 83-006/03L-0:on 830427,during Testing of Spare Pump Installed to Replace Svc Water Pump A,Pump Tripped on Overcurrent.Apparently Caused by Internal Binding of Shaft as Result of Debris in Impeller assembly.W/830526 Ltr ML20028D2441983-01-0707 January 1983 Updated LER 80-009/01T-1:on 800414,primary to Secondary Leak of Approx 0.5 Gpm Detected in B Steam Generator,Exceeding Tech Spec Limit.Caused by Leaking Tubes.Leaks Repaired by Explosive Plugging ML20028B0691982-11-17017 November 1982 LER 82-017/01L-0:on 821104,w/unit at 80% Power,Operator Discovered Isolation Valve Tank Isolation Valve Closed.Cause Undetermined.Valve Locked Open & Procedures Changed to Ensure That Valve Remains Open ML20027D9181982-11-0303 November 1982 Updated LER 82-005/01T-1:on 820628,during Refueling Shutdown,Main Steam Check Valve B Found in Degraded Condition.Caused by Set Screws Which Lock Valve Disc tail- Piece to Rockshaft Loosened by Vibration.Set Screws Staked ML20050C2911982-03-25025 March 1982 Updated LER 79-034/03L-1:on 790918,motor Operated Isolation Valve AFW-V2-16A in Auxiliary Feedwater Line to Steam Generator a Failed to Open During Monthly Periodic Test. Caused by Power Supply Breaker Trip on Previous Closure ML20042A5711982-03-0909 March 1982 LER 82-002/03L-0:on 820207,condensate Measuring Sys Breaker HVH-1 Tripped During Periodic Testing.Caused by Reverse Rotation Due to Missing Discharge Damper Louver.Reverse Rotation Stopped.Damper Repairs Underway ML20049J5071982-03-0202 March 1982 LER 81-033/01X-1:on 811228,error in Tech Specs Heatup & Cooldown Curves Determined to Be Reportable.Caused by Calculational Mistake & Not Revised Due to Administrative Error.Corrected Curves & Calculations Will Be Submitted ML20040B5701982-01-11011 January 1982 LER 81-033/01T-0:on 811228,error in Tech Spec Heatup & Cooldown Curves Found to Be Not Reported to Nrc.Caused by Administrative Reporting Failure & Errors in Calculation. Info Will Be Reported as Tech Spec Change by 820131 ML20040C9471982-01-0808 January 1982 LER 81-034/03L-0:on 811211,loop 2 Steamline Pressure Channel Indicated Higher than Other Channels.Caused by Frozen Sensing Lines in Pressure Transmitter & Failure to Return Freeze Protection Circuit to Svc After Maint ML20039F7481982-01-0404 January 1982 LER 81-032/03L-0:on 811205,boric Acid Transfer Pump a Tripped & Was Declared Inoperable.Caused by Error in Valve Lineup Procedure & Open Winding in Transfer Pump Motor. Procedure Revised & Motor Replaced ML20039F4831981-12-30030 December 1981 LER 81-029/03L-0:on 811130,w/unit at Hot Shutdown,Leak Was Discovered in Chemical & Vol Control Sys.Caused by Failed bonnet-to-body Gasket on Valve CVC-291.Gasket Replaced ML20039D3281981-12-23023 December 1981 LER 81-030/03L-0:on 811130,emergency Diesel Generator B Failed to Reach Rated Output Voltage Following Automatic Start Initiated by Safety Injection Signal.Caused by Faulty auto-voltage Adjust Reostat.Failure Due to Normal Wear ML20039D1831981-12-23023 December 1981 LER 81-028/03L-0:on 811125,steam Generator low-low Level Trip & Alarm Bistables BS-494-A1 & BS-494-A2 Found to Be Inoperable During Periodic Test PT-5.5 W/Unit at Cold Shutdown.Caused by Failure of Instrument Channel LI-494 ML20038C9061981-12-0404 December 1981 LER 81-026/01T-0:on 811120,primary to Secondary Leak of Approx 1.5 Gpm Found in Steam Generator A.Caused by Leaking Explosive Plug.Plant Shut Down,Plug Removed & Weld Repaired on 811127 ML20038C7281981-12-0202 December 1981 LER 81-025/03L-0:on 811102,emergency Diesel Generator B Failed to Start Manually.Caused by Loss of Prime in Fuel Oil Sys,Possibly Due to Debris in Ball Check Valve.Generator Returned to Svc ML20011A6211981-10-20020 October 1981 Updated LER 81-007/01T-1:on 810122,potential Modeling Error in ECCS Model Used for LOCA Analysis Reported.Caused by Shift in Peak Clad Temp.New ECCS Analysis Performed in Aug 1981.No Impact on Public Health & Safety ML20011A7311981-10-19019 October 1981 Updated LER 80-014/01T-1:on 800702,vendor Info Indicated That No Certification of Qualification Was Available for PVC Electric Cable Pigtails Used on Eight Penetrations.Cable Pigtails Meet Design Specs & Accident Requirements ML20011A3451981-10-0101 October 1981 LER 81-020/03L-0:on 810902,containment Spray Check Valve SI-890B & Associated Flow Path Declared Inoperable.Caused by Failure to Perform Post Maint Testing Prior to Startup Due to Oversight.Valve Tested.Procedures Will Be Revised ML20010B0731981-08-0404 August 1981 LER 81-019/03L-0:on 810705,w/unit at 95% Power,Svc Water Booster Pump (Swbp) a Motor Tripped.On 810706,SWBP a Motor Tripped Again.Caused by Normal Wear of Motor Bearings & Possible Breaker Problem,Respectively ML20009H6101981-07-31031 July 1981 LER 81-018/03L-0:on 810701,Channel I (PI-474) of a Steam Generator Steam Line Pressure Indicated High Compared to Two Redundant Channels.Caused by Throttled Root Isolation Valve MSV-14.Valve Reopened ML20009H3581981-07-30030 July 1981 Updated LER 81-004/03L-1:on 810116,primary Coolant Sys Leak Found.Caused by Sample Cooler Tube Bundle Leakage Due to Normal Wear.Bundle Replaced.Review of Maint Records Revealed No Generic Problems ML20009E5561981-07-16016 July 1981 LER 81-017/03L-0:on 810619,auxiliary Feedwater Pump a Tripped on Low Discharge Pressure.Caused by Improper Throttle Setting of Discharge Valve.Valve Repositioned ML20009G1181981-07-10010 July 1981 LER 81-016/03L-0:on 810611,during Startup,Motor Driven Auxiliary Feedwater Pump a Tripped Due to Low Discharge Pressure While Feeding Steam Generators.Event Reoccurred on 810716.Caused by Backleakage Through Discharge Valve AFW-40 ML20005A1921981-06-24024 June 1981 LER 81-015/03L-0:on 810525,computer Box FM-475 Found to Be Out of Acceptable Tolerances & Several Checkpoints Showed Erratic Readings During Loop a Steam Flow Channel Investigation.Caused by Two Worn Electronic Components ML20009G0181981-06-22022 June 1981 LER 81-014/03L-0:on 810523,discovered That Hagan Summator PM-446B Had Shifted Nonconservatively Approx 3%.Caused by Failure of Filter Capacitor Due to Normal Wear.Faulty Capacitor Replaced ML20004E7441981-06-0909 June 1981 Updated LER 81-013/03L-1:on 810415,determined Containment Isolation Valves Not Tested in Required Manner.Seven of Eight Valves Functioning as Designed.Eighth Valve Tested & Shown Operable.Test Undergoing Revision 1983-07-05
[Table view] Category:RO)
MONTHYEARML20024B7371983-07-0505 July 1983 LER 83-011/03L-0:on 830605,circuit Breaker for Boron Injection Tank Heater Channel B Tripped.Caused by Component Failure Due to Normal End of Life.Failed Heater Replaced. W/830705 Ltr ML20023E0791983-05-27027 May 1983 LER 83-007/03L-0:on 830429,PORV RC-455C Failed to Meet Required Cycle Time & Failed to Open Fully on Subsequent Attempt.Caused by Galling of Valve Plug to Cage Due to Rubbing of Stainless Steel in Dry condition.W/830527 Ltr ML20023E0671983-05-26026 May 1983 LER 83-006/03L-0:on 830427,during Testing of Spare Pump Installed to Replace Svc Water Pump A,Pump Tripped on Overcurrent.Apparently Caused by Internal Binding of Shaft as Result of Debris in Impeller assembly.W/830526 Ltr ML20028D2441983-01-0707 January 1983 Updated LER 80-009/01T-1:on 800414,primary to Secondary Leak of Approx 0.5 Gpm Detected in B Steam Generator,Exceeding Tech Spec Limit.Caused by Leaking Tubes.Leaks Repaired by Explosive Plugging ML20028B0691982-11-17017 November 1982 LER 82-017/01L-0:on 821104,w/unit at 80% Power,Operator Discovered Isolation Valve Tank Isolation Valve Closed.Cause Undetermined.Valve Locked Open & Procedures Changed to Ensure That Valve Remains Open ML20027D9181982-11-0303 November 1982 Updated LER 82-005/01T-1:on 820628,during Refueling Shutdown,Main Steam Check Valve B Found in Degraded Condition.Caused by Set Screws Which Lock Valve Disc tail- Piece to Rockshaft Loosened by Vibration.Set Screws Staked ML20050C2911982-03-25025 March 1982 Updated LER 79-034/03L-1:on 790918,motor Operated Isolation Valve AFW-V2-16A in Auxiliary Feedwater Line to Steam Generator a Failed to Open During Monthly Periodic Test. Caused by Power Supply Breaker Trip on Previous Closure ML20042A5711982-03-0909 March 1982 LER 82-002/03L-0:on 820207,condensate Measuring Sys Breaker HVH-1 Tripped During Periodic Testing.Caused by Reverse Rotation Due to Missing Discharge Damper Louver.Reverse Rotation Stopped.Damper Repairs Underway ML20049J5071982-03-0202 March 1982 LER 81-033/01X-1:on 811228,error in Tech Specs Heatup & Cooldown Curves Determined to Be Reportable.Caused by Calculational Mistake & Not Revised Due to Administrative Error.Corrected Curves & Calculations Will Be Submitted ML20040B5701982-01-11011 January 1982 LER 81-033/01T-0:on 811228,error in Tech Spec Heatup & Cooldown Curves Found to Be Not Reported to Nrc.Caused by Administrative Reporting Failure & Errors in Calculation. Info Will Be Reported as Tech Spec Change by 820131 ML20040C9471982-01-0808 January 1982 LER 81-034/03L-0:on 811211,loop 2 Steamline Pressure Channel Indicated Higher than Other Channels.Caused by Frozen Sensing Lines in Pressure Transmitter & Failure to Return Freeze Protection Circuit to Svc After Maint ML20039F7481982-01-0404 January 1982 LER 81-032/03L-0:on 811205,boric Acid Transfer Pump a Tripped & Was Declared Inoperable.Caused by Error in Valve Lineup Procedure & Open Winding in Transfer Pump Motor. Procedure Revised & Motor Replaced ML20039F4831981-12-30030 December 1981 LER 81-029/03L-0:on 811130,w/unit at Hot Shutdown,Leak Was Discovered in Chemical & Vol Control Sys.Caused by Failed bonnet-to-body Gasket on Valve CVC-291.Gasket Replaced ML20039D3281981-12-23023 December 1981 LER 81-030/03L-0:on 811130,emergency Diesel Generator B Failed to Reach Rated Output Voltage Following Automatic Start Initiated by Safety Injection Signal.Caused by Faulty auto-voltage Adjust Reostat.Failure Due to Normal Wear ML20039D1831981-12-23023 December 1981 LER 81-028/03L-0:on 811125,steam Generator low-low Level Trip & Alarm Bistables BS-494-A1 & BS-494-A2 Found to Be Inoperable During Periodic Test PT-5.5 W/Unit at Cold Shutdown.Caused by Failure of Instrument Channel LI-494 ML20038C9061981-12-0404 December 1981 LER 81-026/01T-0:on 811120,primary to Secondary Leak of Approx 1.5 Gpm Found in Steam Generator A.Caused by Leaking Explosive Plug.Plant Shut Down,Plug Removed & Weld Repaired on 811127 ML20038C7281981-12-0202 December 1981 LER 81-025/03L-0:on 811102,emergency Diesel Generator B Failed to Start Manually.Caused by Loss of Prime in Fuel Oil Sys,Possibly Due to Debris in Ball Check Valve.Generator Returned to Svc ML20011A6211981-10-20020 October 1981 Updated LER 81-007/01T-1:on 810122,potential Modeling Error in ECCS Model Used for LOCA Analysis Reported.Caused by Shift in Peak Clad Temp.New ECCS Analysis Performed in Aug 1981.No Impact on Public Health & Safety ML20011A7311981-10-19019 October 1981 Updated LER 80-014/01T-1:on 800702,vendor Info Indicated That No Certification of Qualification Was Available for PVC Electric Cable Pigtails Used on Eight Penetrations.Cable Pigtails Meet Design Specs & Accident Requirements ML20011A3451981-10-0101 October 1981 LER 81-020/03L-0:on 810902,containment Spray Check Valve SI-890B & Associated Flow Path Declared Inoperable.Caused by Failure to Perform Post Maint Testing Prior to Startup Due to Oversight.Valve Tested.Procedures Will Be Revised ML20010B0731981-08-0404 August 1981 LER 81-019/03L-0:on 810705,w/unit at 95% Power,Svc Water Booster Pump (Swbp) a Motor Tripped.On 810706,SWBP a Motor Tripped Again.Caused by Normal Wear of Motor Bearings & Possible Breaker Problem,Respectively ML20009H6101981-07-31031 July 1981 LER 81-018/03L-0:on 810701,Channel I (PI-474) of a Steam Generator Steam Line Pressure Indicated High Compared to Two Redundant Channels.Caused by Throttled Root Isolation Valve MSV-14.Valve Reopened ML20009H3581981-07-30030 July 1981 Updated LER 81-004/03L-1:on 810116,primary Coolant Sys Leak Found.Caused by Sample Cooler Tube Bundle Leakage Due to Normal Wear.Bundle Replaced.Review of Maint Records Revealed No Generic Problems ML20009E5561981-07-16016 July 1981 LER 81-017/03L-0:on 810619,auxiliary Feedwater Pump a Tripped on Low Discharge Pressure.Caused by Improper Throttle Setting of Discharge Valve.Valve Repositioned ML20009G1181981-07-10010 July 1981 LER 81-016/03L-0:on 810611,during Startup,Motor Driven Auxiliary Feedwater Pump a Tripped Due to Low Discharge Pressure While Feeding Steam Generators.Event Reoccurred on 810716.Caused by Backleakage Through Discharge Valve AFW-40 ML20005A1921981-06-24024 June 1981 LER 81-015/03L-0:on 810525,computer Box FM-475 Found to Be Out of Acceptable Tolerances & Several Checkpoints Showed Erratic Readings During Loop a Steam Flow Channel Investigation.Caused by Two Worn Electronic Components ML20009G0181981-06-22022 June 1981 LER 81-014/03L-0:on 810523,discovered That Hagan Summator PM-446B Had Shifted Nonconservatively Approx 3%.Caused by Failure of Filter Capacitor Due to Normal Wear.Faulty Capacitor Replaced ML20004E7441981-06-0909 June 1981 Updated LER 81-013/03L-1:on 810415,determined Containment Isolation Valves Not Tested in Required Manner.Seven of Eight Valves Functioning as Designed.Eighth Valve Tested & Shown Operable.Test Undergoing Revision 1983-07-05
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217A1691999-09-22022 September 1999 Part 21 Rept Re Engine Sys,Inc Controllers,Manufactured Between Dec 1997 & May 1999,that May Have Questionable Soldering Workmanship.Caused by Inadequate Personnel Training.Sent Rept to All Nuclear Customers RA-97-0258, LER 97-S12-00:on 971119,discovered Uncompensated Security Zone.Caused by Inattention to Detail by Members of Security Force.Provided Event Info to Security Shift Personnel & Changed Practice Re Zone Review1997-12-19019 December 1997 LER 97-S12-00:on 971119,discovered Uncompensated Security Zone.Caused by Inattention to Detail by Members of Security Force.Provided Event Info to Security Shift Personnel & Changed Practice Re Zone Review ML20211M6491997-10-0808 October 1997 Addenda 1 to Part 21 Rept Re Weldments on Opposed Piston & Coltec-Pielstick Emergency stand-by Diesel gen-set lube-oil & Jacket Water Piping Sys.Revised List of Potentially Affected Utils to Include Asterisked Utils,Submitted ML20217Q2751997-06-30030 June 1997 CP&L Fitness for Duty Program Performance Data for Period 970101-0630 ML14183A6951995-09-18018 September 1995 Safety Evaluation Approving Relocation of Technical Support Ctr ML20059H7721994-01-17017 January 1994 Part 21 Rept Re Virginia Power Notifying Fairbands Morse Via Failure Analysis Rept NESML-Q-058 of Defective Air Start Distributor cam,16104412 ML17352A8691993-05-31031 May 1993 Technical Rept, Assessment of Aging Degradation of Civil/ Structural Features at Selected Operating Nuclear Power Plants. ML20125C7161992-12-0707 December 1992 Part 21 Rept Re Possibility for Malfunction of Declutching Mechanisms in SMB/SB-000 & SMB/SB/SBD-00 Actuators. Malfunction Only Occurs During Seismic Event.Balanced Levers May Be Purchased from Vendor.List of Affected Utils Encl ML20127P5861992-11-23023 November 1992 Followup to 921005 Part 21 Rept Re Potential Defect in SB/SBD-1 Housing Cover Screws.Procedure Re Replacement of SBD-1 Spring Cover Bolts Encl.All Fasteners Should Be Loosened & Removed.List of Affected Utils Encl ML20118B4391992-09-11011 September 1992 Part 21 Rept Re Degradation in Abb Type 27N Undervoltage Relays Used in Electrical Switchgear.Recommends That Users Review Applications Requiring Exposures Greater than 1E03 Rads TID W/Time Delay Function Option ML20079H1571991-09-30030 September 1991 Nonproprietary Evaluation of Revised Transfer to Cold Leg Recirculation Procedure,Hb Robinson Unit 2 ML20086T2951991-06-14014 June 1991 Rev 1 to EQ Documentation Package Eqdp 36.0, Boston Insulated Wire Cable ML20086T2861991-03-0808 March 1991 Rev 1 to EQ Documentation Package Eqdp 11.1, Dekoron Instrumentation Cables ML20086T2561991-03-0808 March 1991 Rev 1 to EQ Documentation Package 10.0, Continental Shielded Instrument Cable ML20065K6961990-10-31031 October 1990 Mechanical Licensing Rept for Hb Robinson High Thermal Performance Fuel Assemblies ML20065K6971990-10-31031 October 1990 Thermal Hydraulic Compatibility Analysis of Anf High Thermal Performance Fuel for Hb Robinson,Unit 2 ML20005G6831990-01-0505 January 1990 Part 21 Rept Re Installation Instructions for Grommet Use Range for Patel Conduit Seal P/N 841206.Conduit Seals in Environ Qualification Applications Inspected for Proper Wire Use Range & Grommets Replaced ML20247E0701989-07-20020 July 1989 Info Rept:On 890717-0804,fire Penetration Seals Will Be Removed from Svc to Allow Access for Ventilation Sys Mod. Addl Fire Barrier Penetrations Will Be Made in Wall Between RHR Pump Pit & Fuel Handling Bldg,Per Tech Spec 3.14.7.2 ML20246E9111989-03-31031 March 1989 PDC-3:Advanced Nuclear Fuels Corp Power Distribution Control for PWRs & Application of PDC-3 to Hb Robinson Unit 2 ML20245H0821989-01-25025 January 1989 Criticality Safety Analysis of Hb Robinson Spent Fuel Pool W/4.2% Nominal Enrichment Fuel Assemblies ML20205T0551988-10-31031 October 1988 Responses to NRC Questions on RTD Bypass Elimination Licensing Rept ML20147E2371988-02-29029 February 1988 1987 Annual Rept - Primary Coolant Iodine Spikes ML20147B1971987-12-31031 December 1987 1987 Annual Rept - Primary Safety & Relief Valve Challenges ML20236K7731987-10-31031 October 1987 Monthly Operating Rept for Oct 1987 ML20235W3781987-09-30030 September 1987 Monthly Operating Rept for Sept 1987 ML20238E2741987-08-31031 August 1987 Monthly Operating Rept for Aug 1987 ML20235H3151987-06-30030 June 1987 Monthly Operating Rept for June 1987 ML17261A5301987-06-18018 June 1987 Part 21 Rept Re Potential Util Failure to Comply W/Component Containment Isolation Licensing Commitment If Proposed Mods to Component Cooling Water Sys Instituted.Utils Advised to Evaluate Containment Isolation Sys ML20214W3241987-05-31031 May 1987 Monthly Operating Rept for May 1987 ML20214R5101987-04-30030 April 1987 Rev 1 to Monthly Operating Rept for Apr 1987,correcting Operation Statistics & Shutdown Experience Due to Mathematical Errors ML20215L4941987-04-30030 April 1987 Monthly Operating Rept for Apr 1987 ML20206F3561987-03-31031 March 1987 Monthly Operating Rept for Mar 1987 ML20210B4141987-03-31031 March 1987 Revised Monthly Operating Rept for Mar 1987 ML20205F6021987-03-23023 March 1987 Special Rept:On 870302,noble Gas Effluent Monitor for Main Steam Line B Declared Inoperable & Svc Not Returned Until 870312.Caused by Defective Detector.Detector Replaced.High Voltage for Detector Adjusted & Sys Operation Checked ML20212P3101987-02-28028 February 1987 Monthly Operating Rept for Feb 1987 ML20214Q7891987-01-31031 January 1987 Cycle 12,SAR ML20210R6341987-01-31031 January 1987 Monthly Operating Rept for Jan 1987 ML20207M2451986-12-31031 December 1986 Monthly Operating Rept for Dec 1986 L-18-120, Rev 0 to Supplemental Info in Support of Conservatisms in Criticality Analysis Performed for Hb Robinson Isfsi1986-12-18018 December 1986 Rev 0 to Supplemental Info in Support of Conservatisms in Criticality Analysis Performed for Hb Robinson Isfsi ML20215C7911986-11-30030 November 1986 Monthly Operating Rept for Nov 1986 ML20213F3121986-10-31031 October 1986 Monthly Operating Rept for Oct 1986 ML20215G1081986-09-30030 September 1986 Monthly Operating Rept for Sept 1986 ML20215F0361986-09-29029 September 1986 Special Rept:On 860902,during Cold Shutdown,Pressurizer PORV Lifted Twice to Prevent Overpressurization.Caused by Inadvertent Action by Unit Operators.Operations Personnel Counseled Re Importance of Breaker Position Indicators ML20211C0641986-09-0909 September 1986 Rev 0 to Final Rept Criticality Safety Analysis Hb Robinson Spent Fuel Storage Racks (Unpoisoned,Low Density) W/4.2% Enriched 15x15 Fuel Assemblies ML20211C0491986-09-0202 September 1986 Rev 0 to Final Rept Criticality Safety Analysis Hb Robinson New Fuel Storage Vault W/4.2% Enriched 15x15 Fuel Assemblies ML20212F5321986-07-31031 July 1986 Monthly Operating Rept for Jul 1986 ML20203D0221986-07-14014 July 1986 Part 21 Rept Re Air Monitoring Sys Probes Exhibiting Blue Tip Rather than Normal White Tip & Insensitive to Chlorine. Caused by Improper Handling/Storage.Advisory Bulletin Encl. Item Not Reportable Per Part 21 ML20202G3371986-06-30030 June 1986 Monthly Operating Rept for June 1986 ML20211B5601986-05-31031 May 1986 Monthly Operating Rept for May 1986 ML20197D2651986-04-30030 April 1986 Monthly Operating Rept for Apr 1986 1999-09-22
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R S. NUCtEAR REMATORMOMMISSION
""f,'
g 0"" 38" Update Report - Previous Report Date Was 9/18/79
, i.lCENSEE EVENT REPORT CONTROL ELOCX: l 1
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(PLEASE PRINT OR TYPE ALL REQUl%ED INFORMATION) l@l67 CAT b8l@
0 1 l 7 8 [$!ClHlBlRl2l@150 9 LICENSEE CODE 14 l0 l- l0 l0
, LeCf l0 l0 l0 l- l0 l0 l@4 NSE NUMBER 2') 26 l1 LICENSE l1 l1TYPE l1 JO CON'T O t I 8 7n"c' Ql 60 0 l 695 l 0 l 0DOCK l 0ETlNUMBER 2 l 6 l 1 @l to 069l 9 11 l8 l 7 l 9 l@l 075 l 3 REPORT EVENT DATE 14 l 2 l 5DATE l 8 l 280l@
EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h o 2 Mhile performing the monthly pericole test of the AFW System, the motor operated iso- l O 3 llation valve in the AFW line to "A" S/G, AFW-V2-16A, failed to open. The valve was l o 4 l declared inoperable at 1900 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.2295e-4 months <br />. This resulted in operation in a degraded mode l 10151 IPermitted by T.S. 3.4.3 and constitutes a reportable occurrence per T.S. 6.9.2.b.2. l O s [Throughout the event botn main feed pumps and three auxiliary feedwater pumps were l IO ITl lavailable. Also, V2-16A was manually operable if required. Therefore, there was no l O R l threat to either plant or public safety. (LER 79-32) (LER 79-33). l 7 8 9 80 SYSTEM CAUSE CAUSE COMP. VALVE CODE CODE SUBCODE COMPONENT CODE SU8 CODE SUBCODE 7
O 9 8
l11l H j@ W@ W@ l Vl Al Ll Vl 0l plh W@ y h 9 to 11 12 13 18 19 20
. SE QUE N Yl AL OCCURRENCE REPORT REVISION t E R/RO EVENTYEAR REPORT NO. CODE TYPE N O.
O ajoT' s 71 91
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27 IOI3I 28 29 Lt_]
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33 34 35 2 40 48 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i o lThe operator on V2-16A failed to open due to the operator power supply breaker having g i i l tripped on the previous closure. The breaker was reset, and the valve declared g i 2 loperable at 2d32 bours after Iuriins been stroked several times with no problems. The ;
i a iroot canae 6t the fai3ure was subsequebtly determined to be a worn gear in the valve g
M 'loperator, The valve has bsen replaced,'and no further corrective action is necessary. ;
~
7 8 9 Bo STA % POWER' OTHERSTATUS i o Y DISCOVERY DESCRIPTION t 5 W h (0 l9 l6 l h l N/A l W @l Operator Observation l ACTIVITY C TENT net.E AsEn OF RELE ASE AMOUNT OF ACTIVITY LOCATION OF RELEASE 7
t c 8 9 W @ (@l 10 11 N/A 44 l l 45 N/A 80 l
PERSONNE L EXPOSURES NUMBE R i 7 l 0 l 0 l 0 lh[TYPEZ_jhl DESCRIPTION N/A l PEnSoNNELmOLS NUvnE n oESCniPTwNO 7-1 E
,8 l0l0l0l@l 9 11 12 \
N/A 80
.l LOS$ rF OR DAMAGE TO F ACillTY TYPE DESCFilPTION t 9 Lt_]@l10 N/A l 7 8 in CO
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- ISSUt ITTTI I N f@l DESCRIPTION N/A l lllllllllllll{
8204000378 820326 68 SS 8o 5 DR ADOCK 05000 Howard T. Cox (803) 383-4524 pgong: {
'e SUPPLEMENTAL INFORMATION FOR
~ LICENSEE EVENT REPORT 79-34R1
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- 1. Cause Description and Analysis e, a The valve failures occurred when the motor driven auxiliary feedwater pumpa were started and AFW-V2-16A failed to open. This failure occurred initially when the AFW pumps were being used to maintain steam generator level with the reactor at zero power on 9/5/79 and
, , again during the performance of the monthly periodic test of the AFW
-f c System on 9/6/79 and 9/18/79.
Immediate investigation in each case revealed that the thermal over-current relay in the power supply breaker to the valve operator had been' tripped. This overcurrent relay provides for motor protection.
~
, , Additional investigations, performed subsequent to the 9/18/79
' failure, traced the overcurrent_ trip to a torque switch designed to de-energize the operator after the valve has closed. The torque switch is' contacted by'a worm which operated against a spring l mechanism when valve stem movement is restricted. Specifically, motor torque is converted to worm translation which is resisted by the spring. When valve stem travel stops, sufficient torque results in~enough worm translation to contact the torque switch at a given setpoint. In this case, it was determined that the torque' switch was not being contacted on every valve closure. Since the valve was closed but power was not de-energized from the motor, the motor operated in a locked rotor condition until the thermal overcurrent trip operated. Subsequent investigation of the operator internals revealed a badly worn worm gear. The excessive wear of the worm gear is believed to have prevented the transmission of sufficient torque through the worm to cause the. torque switch to be tripped during. valve closure. The excessive worm gear wear is believed to have occurred from overstressing of the gear on previous occasions when the valve stuck closed from thermal binding as a result of system backleakage.
.The main feed pumps and both motor driven auxiliary feedwater pumps were available to supply steam generator feedwater throughout the 9/5/79 and 9/6/79 occurrences. Throughout the 9/18/79 occurrence, the' steam driven auxiliary feedwater pump was also available.
Throughout each event, the AFW-V2-16A was manually operable if required. There was, therefore, no threat to either plant or public safety during.any of these occurrences.
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- 2. Corrective Action Following the 9/5/79 and 9/6/79 failures, the thermal overcurrent relay in the power supply breaker was reset, and the valve was stroked several times. The failure would not repeat, and the valve was declared operable. Following the 9/18/79 failure, investigations revealed that the torque switch was n it being contacted. The thermal overcurrent relay was reset, and the torque switch setting was re-duced as temporary corrective action. The proper operation of the valve with the reduced torque switch setting was verified by stroking.
Following the inveatigation of the valve operator internals, which revealed the excessive worm gear wear, the worn worm gear was re-plac.ed and the operator was returned to service in satisfactory condition.
- 3. Corrective Action To Prevent Further Oct.urrence In order to eliminate system backleakage and thermal binding problems in the Auxiliary Feedwater System motor operated valves, the three motor operated valves in the motor driven train (V2-16A, B, and C) and the three motor operated valves in the steam driven train (V2-14A, B, and C) have been replaced with double disk gate valves. The original valves were solid wedge gate valves which were far more susceptible to this problem. These valves were replaced during the 1980 refueling outage, and no further problems have been experienced with these valves to date. No further corrective action is deemed necessary.
This revision to LER 79-34 also supplements and closes LER 79-32 and 79-33.
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