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Category:LICENSEE EVENT REPORT (SEE ALSO AO
MONTHYEARML20029E1891994-05-13013 May 1994 LER 94-007-00:on 940418,meter Lead Inadvertently Touched Adjacent Terminal Resulting in RCIC Inboard Steam Valve Closure.Caused by Personnel Error.Corrective Action:Meetings Were Held & self-assessments in progress.W/940513 Ltr ML20029D6171994-04-29029 April 1994 LER 94-005-01:on 940330,potential Use of Less Conservative pressure-temp Limit Curves Identified.Caused by Inadequate Procedural Guidance.Corrective Actions:Adverse Condition Rept initiated.W/940429 Ltr ML20029D0051994-04-28028 April 1994 LER 94-005-00:on 940404,two PCIS Group 6 RIP Valves Had Dual Open/Closed (Red/Green) Indications.Cause Was Personnel Error.Corrective Action:Individuals Involved Counseled on event.W/940428 Ltr ML20029C8491994-04-25025 April 1994 LER 94-004-00:on 940329,penetration Leakage in Excess of TS Allowable Limit During Local Leak Rate Testing Identified. Troubleshooting & Analysis of Failure Mechanism in Progress. Suppl to Rept Will Be submitted.W/940425 Ltr ML20046B5601993-07-30030 July 1993 LER 92-004-01:on 920730,RWCU Sys Isolated During Substation E7 de-energization Due to Personnel Error.Preparation of Project Plan for Development of Electrical Load List Using Plant Staff Resources underway.W/930730 Ltr ML20045G5821993-07-0808 July 1993 LER 93-003-00:on 930608,RPS MG a Tripped,Resulting in Successful ESF Actuations & Isolations Due to Defective Procedure.Voltage Adjust Potentiometer for MG a Voltage Regulator Replaced on 930617.W/930708 Ltr ML20045F5201993-07-0202 July 1993 LER 93-010-00:on 930604,hourly Fire Watch TS Surveillance Missed During Radiography Due to HP & Operations Failed to Establish Other Means of Communication W/Radiographers. W/930702 Ltr ML20045D6371993-06-30030 June 1993 LER 93-005-01:on 930214,testing of SBGT Showed That Unthrottled Flow of Single Train Would Exceed TS Rated Flow Limit of 3,330 Cfm.Caused by Design Deficiency.Existing SBGT Heaters Upgraded & Rewired ML20045D7601993-06-30030 June 1993 LER 93-008-01:on 930313,spurious ESF Actuations Occurred Due to on-site Electrical Distribution Sys Voltage Depressions. Design of cross-over Points of Transmission Lines Emanating from Plant Being reviewed.W/930624 Ltr ML20045D1531993-06-21021 June 1993 LER-93-007-00:on 930522,discovered That MSL D High Flow Trip Unit Failed Downscale Due to Personnel Error.Appropriate Operations Personnel counselled.W/930617 Ltr ML20045D5881993-06-17017 June 1993 LER 93-006-00:on 930521,HCU 06-31 Declared Inoperable When CRD Accumulator Low Pressure/High Level Alarm Received in Cr.Hcu 02-23 Inoperable at Time.Hcu 02-23 Restored to Svc & Excess Water Drained from HCU 06-31.W/930617 Ltr ML20044E5241993-05-24024 May 1993 LER 93-007-00:on 930424,discovered That Sampling of Rv Coolant Conductivity Not Performed Due to Misinterpretation of RCS Chemistry Ts.Chemistry Sampling of Rv Coolant re-established.W/930521 Ltr ML20044E5411993-05-20020 May 1993 LER 93-009-00:on 930421,found That Design of SBGTS Would Allow Operation That Would Result in Sys Damage If Containment Venting in Progress & Experience Loca.Operating Procedures 1-OP-10 & 1-OP-24 revised.W/930520 Ltr ML20044B6761993-02-22022 February 1993 LER 93-001-00:on 930121,determined That Containment Atmospheric Control Airborne Particulate & Gaseous Radioactivity Monitors Not Seismically Qualified.Suppl to Rept Will Be submitted.W/930227 Ltr ML20029A9111991-02-25025 February 1991 LER 91-001-00:on 910125,reactor Scram Occurred During Calibr of Feedwater Computer Point.Caused by Incorrect Procedure in Summary Sheet.Maint Procedures Reviewed & revised.W/910225 Ltr ML20028H7141991-01-24024 January 1991 LER 90-019-00:on 901226,isolation Signal Caused Reactor Water Cleanup Inlet Inboard Isolation Valve to Automatically Close.Caused by de-energized HPCI Isolation Relay.Riley Scam Temp Switch Units Will Be replaced.W/910124 Ltr ML20024F7461990-12-13013 December 1990 LER 90-020-00:on 901117,primary & Secondary Containment Isolation Signals Received & Standby Gas Treatment Sys auto- Started.Caused by Scan Overload on Microprocessor.Updated Microprocessor Will Be obtained.W/901213 Ltr ML20028H0421990-09-28028 September 1990 LER 90-012-00:on 900830,Unit 2 Reactor Scram Occurred During Reactor Startup.Investigation Continuing.Level Recovered W/O Need for Safety Sys Injection & Unit Designed for Level Transient from Full power.W/900928 Ltr ML20028H0431990-09-28028 September 1990 LER 90-011-00:on 900830,RWCU Sys G31 Received Leak Hi & RWCU Leak Hi Hi Annunciators Although Actual Leak Had Not Occurred.Caused by Air in Instrument 2-G31-FT-N012 Sensing Lines.Investigation to Be conducted.W/900928 Ltr ML20043G0981990-06-15015 June 1990 LER 88-001-06:on 880102,manual Reactor Protection Sys Trip Initiated Due to Decreasing Condenser Vacuum.Cause Still Undetermined.Vendor Insp Revealed Presence of Oil Base Film in Solenoid Valves.Determination Due by 900801.W/900615 Ltr ML20043G0711990-06-13013 June 1990 LER 90-005-00:on 900514,unplanned Closure of HPCI Isolation Valve Occurred During Maint Surveillance Test.Caused by Technician Placing RCIC Instead of HPCI Test Switch to Test Position.Personnel Counseled & trained.W/900613 Ltr ML20043F6291990-06-11011 June 1990 LER 90-008-00:on 900514,HPCI Sys Rendered Inoperable When Control Power Lost to Min Flow Bypass Valve to Suppression Pool.Probably Caused by Design Problem W/Ge Model CR2940 Sockets.Light Bulb & Fuse replaced.W/900611 Ltr ML20043F6181990-06-0808 June 1990 LER 90-007-00:on 900511,identified That Damper Would Fail to Close on Loss of Power to Solenoid Valve & on 900526,damper Found Approx 30 Degrees Open.Caused by Failure of Design to Include Fail Safe Damper.Damper modified.W/900608 Ltr ML20043C9001990-06-0101 June 1990 LER 90-009-00:on 900507,determined That Tech Spec 4.6.1.1 Requirements Not Met After Performing Monthly Periodic Test 2.2.4a.Caused by Inadequate Procedure.Recommended Procedure Revs to Prevent Recurrence Being evaluated.W/900601 Ltr ML20043B7971990-05-25025 May 1990 LER 90-006-00:on 900426,hydraulic Perturbation Occurred on Variable Leg of Instrumentation Used to Sense Reactor Water Level,Causing Isolation of RWCU Sys & Initiation of Standby Gas Treatment Sys.Diaphragm Assembly recalibr.W/900525 Ltr ML20043A6121990-05-11011 May 1990 LER 90-003-01:on 900312,full Group 1 Isolation Signal Received,Resulting in Automatic Closure of Msivs.Caused by Personnel Failing to Follow Procedures.Personnel Counseled & Procedure Separated Into Two tests.W/900511 Ltr ML20012E0581990-03-23023 March 1990 LER 90-002-00:on 900224,Group I Isolation Occurred When Undervoltage Relay Replaced.Caused by Lack of Recognition of Significance of Having Turbine Reset While Performing Electro Hydraulic Control evolutions.W/900323 Ltr ML20012B8071990-03-0909 March 1990 LER 90-001-00:on 900210,determined That Core Spray Loops a & B Inoperable Due to Missed Surveillance.Cause Not Stated. Investigation continuing.W/900309 Ltr ML20012A1671990-03-0202 March 1990 LER 89-013-01:on 890909,HPCI Turbine Auxiliary Oil Pump Developed Shaft Seal Leak of Approx 1 Gpm.Caused by Failure of Shaft Seal.Root Cause of Seal Failure Initiated.Pump Seal replaced.W/900302 Ltr ML20011F5541990-02-22022 February 1990 LER 90-002-00:on 900127,common Control Bldg HVAC Sys Isolated & Transferred to Recirculation Mode as Result of Spurious Actuation of Chlorine Detector.Sensor Connection checked.W/900222 Ltr ML20006E7751990-02-19019 February 1990 LER 88-001-05:on 880102,manual Reactor Protection Sys Trip Initiated Due to Decreasing Condenser Vacuum.Caused by Numerous Leaks on Main Turbine & Main Steam Reheat Interconnecting Piping.Seating Matl installed.W/900219 Ltr ML20011F5311990-02-16016 February 1990 LER 89-026-01:on 891210,common Emergency Bus E3 Unexpectedly Deenergized,Causing Standby Gas Treatment Sys Isolation & Reactor Scram Signal.Caused by Procedural Inadequacy.Isolation Reset & Power restored.W/900216 Ltr ML20006E3681990-02-0909 February 1990 LER 88-006-02:on 880219,numerous Bolt Head Failures of 5/16- Inch X 1/2-inch Silicon Bronze Carriage Bolts Noted in Bus/ Bar Connections of Electrical Switchboards.Caused by Igscc. Bolts Replaced.Reportable Per Part 21.W/900209 Ltr ML20011E1601990-02-0101 February 1990 LER 90-001-00:on 900102,RCIC Removed from Svc & HPCI Rendered Inoperable,Placing Unit in Tech Spec 3.0.3.Caused by Personnel Error.Individual Counseled & Standing Instruction 90-003 issued.W/900201 Ltr ML19354E5651990-01-24024 January 1990 LER 89-021-00:on 891225,electrical Protection Assembly Output Breakers Associated W/Bus a of Reactor Protection Sys Tripped Open.Cause of Trip Unknown.Voltage & Frequency Output of Motor Generator a monitored.W/900124 Ltr ML19354E5611990-01-19019 January 1990 LER 89-025-00:on 891223,sample Lines for Stack Radiation Monitor Froze,Resulting in Samples Not Indicative of Ongoing Releases.Caused by Lack of Insulation on Lines Exiting Stack.Sample Lines insulated.W/900119 Ltr ML19354D8951990-01-16016 January 1990 LER 89-020-00:on 891217,relay in Reactor Protection Sys B Motor Generator Set Control Panel Burned Out,Resulting in Logic Trip of Bus B & Isolation of Standby Gas Treatment Sys.Caused by Circuit malfunction.W/900116 Ltr ML20005F0501990-01-0404 January 1990 LER 89-026-00:on 891210,loss of E3 Bus While Deenergizing Bus 2D for Scheduled Maint Occurred.Caused by Procedural Inadequacy of Plant Electric Sys Operating Procedures.Unit Reset & Sys Returned to normal.W/900104 Ltr ML20042D3551990-01-0202 January 1990 LER 89-019-00:on 891208,Group 6 Isolation Occurred W/Standby Gas Treatment Sys Auto Start During Performance of MST-SCIS21R.Caused by Inadequate Work Practices.Work Crew Counseled.Calibr Procedures May Be revised.W/900102 Ltr ML20005E3461989-12-27027 December 1989 LER 89-024-00:on 891127,17 Primary Containment Isolation Valves Not Tested Per Tech Spec Surveillance Requirement 4.6.1.1.a.Caused by Failure to Recognize Applicability of Testing.Test Rev completed.W/891227 Ltr ML20011D8411989-12-15015 December 1989 LER 89-009-01:on 890617,manual Reactor Scram Initiated Per NRC Bulletin 88-007 Due to Loss of Recirculation Pumps, Causing Loss of Offsite Power & Containment Isolation. Caused by Personnel Error.Hpci Sys secured.W/891215 Ltr ML20011D2251989-12-14014 December 1989 LER 89-023-00:on 891116,reactor Shutdown When Drywell to Suppression Chamber Vacuum Breaker Opened.Caused by Excessive Vibration & Lack of Proper Space Between Actuator Arm & Piston.Procedures Will Be revised.W/891214 Ltr ML19332E9001989-12-0707 December 1989 LER 89-022-00:on 891110,automatic Isolation of Units 1 & 2 Common Control Bldg HVAC & Emergency Air Filtration Sys Occurred.Cause Not Determined.Detectors auto-reset & Sys Returned to Normal svc.W/891207 Ltr ML19332D5791989-11-27027 November 1989 LER 89-018-00:on 891101,determined That Safety Relief Valves Did Not Actuate within Required +/- 1.0% of Setpoints.Cause Not Determined.Setpoints recertified.W/891127 Ltr ML19332C3861989-11-21021 November 1989 LER 89-021-00:on 891022,inadvertent LOCA Initiation Signal Occurred During Monthly Channel Calibr & Functional Test. Caused by Technician Miscommunication.Involved Technicians counseled.W/891121 Ltr ML19327C2021989-11-14014 November 1989 LER 89-019-01:on 890914,determined That Svc Water Sys May Not Have Met Design Requirements Under worst-case Conditions.Caused by Inadequate Component design.Cross-tie Valves Installed.Also Reported Per Part 21.W/891114 Ltr ML19324C3171989-11-0707 November 1989 LER 89-020-00:on 891011,HPCI F006 Valve Motor Control Ctr Indicating Light Socket Shorted & Blew Control Power Fuse for Valve.Caused by Inward Force Applied to Bulb During Removal.Lamp,Socket & Fuse replaced.W/891107 Ltr ML19324C1041989-11-0606 November 1989 LER 89-017-00:on 891010,low Level Signals Occurred,Causing Group 1 Isolation,Core Spray Initiation Signal & auto-start of Common Emergency Diesel Generators.Caused by Perturbation of Ref Leg.Procedures revised.W/891106 Ltr ML19327B9861989-11-0606 November 1989 LER 89-017-01:on 890624,HPCI Sys,Steam Line Break Delta Pressure High Signal,Channel A,Isolation Occurred.Root Cause Investigation Underway.Work Request/Job Order Initiated Requesting Verification of readings.W/891106 Ltr ML19354D4401989-11-0101 November 1989 LER 89-016-01:on 890614,determined That Some Valves Listed in Table 1 of LER Not Tested Per Tech Specs.Caused by Failure to Establish Proper Procedural Controls.Valve Acceptance Criteria Basis Sheets updated.W/891101 Ltr 1994-05-13
[Table view] Category:RO)
MONTHYEARML20029E1891994-05-13013 May 1994 LER 94-007-00:on 940418,meter Lead Inadvertently Touched Adjacent Terminal Resulting in RCIC Inboard Steam Valve Closure.Caused by Personnel Error.Corrective Action:Meetings Were Held & self-assessments in progress.W/940513 Ltr ML20029D6171994-04-29029 April 1994 LER 94-005-01:on 940330,potential Use of Less Conservative pressure-temp Limit Curves Identified.Caused by Inadequate Procedural Guidance.Corrective Actions:Adverse Condition Rept initiated.W/940429 Ltr ML20029D0051994-04-28028 April 1994 LER 94-005-00:on 940404,two PCIS Group 6 RIP Valves Had Dual Open/Closed (Red/Green) Indications.Cause Was Personnel Error.Corrective Action:Individuals Involved Counseled on event.W/940428 Ltr ML20029C8491994-04-25025 April 1994 LER 94-004-00:on 940329,penetration Leakage in Excess of TS Allowable Limit During Local Leak Rate Testing Identified. Troubleshooting & Analysis of Failure Mechanism in Progress. Suppl to Rept Will Be submitted.W/940425 Ltr ML20046B5601993-07-30030 July 1993 LER 92-004-01:on 920730,RWCU Sys Isolated During Substation E7 de-energization Due to Personnel Error.Preparation of Project Plan for Development of Electrical Load List Using Plant Staff Resources underway.W/930730 Ltr ML20045G5821993-07-0808 July 1993 LER 93-003-00:on 930608,RPS MG a Tripped,Resulting in Successful ESF Actuations & Isolations Due to Defective Procedure.Voltage Adjust Potentiometer for MG a Voltage Regulator Replaced on 930617.W/930708 Ltr ML20045F5201993-07-0202 July 1993 LER 93-010-00:on 930604,hourly Fire Watch TS Surveillance Missed During Radiography Due to HP & Operations Failed to Establish Other Means of Communication W/Radiographers. W/930702 Ltr ML20045D6371993-06-30030 June 1993 LER 93-005-01:on 930214,testing of SBGT Showed That Unthrottled Flow of Single Train Would Exceed TS Rated Flow Limit of 3,330 Cfm.Caused by Design Deficiency.Existing SBGT Heaters Upgraded & Rewired ML20045D7601993-06-30030 June 1993 LER 93-008-01:on 930313,spurious ESF Actuations Occurred Due to on-site Electrical Distribution Sys Voltage Depressions. Design of cross-over Points of Transmission Lines Emanating from Plant Being reviewed.W/930624 Ltr ML20045D1531993-06-21021 June 1993 LER-93-007-00:on 930522,discovered That MSL D High Flow Trip Unit Failed Downscale Due to Personnel Error.Appropriate Operations Personnel counselled.W/930617 Ltr ML20045D5881993-06-17017 June 1993 LER 93-006-00:on 930521,HCU 06-31 Declared Inoperable When CRD Accumulator Low Pressure/High Level Alarm Received in Cr.Hcu 02-23 Inoperable at Time.Hcu 02-23 Restored to Svc & Excess Water Drained from HCU 06-31.W/930617 Ltr ML20044E5241993-05-24024 May 1993 LER 93-007-00:on 930424,discovered That Sampling of Rv Coolant Conductivity Not Performed Due to Misinterpretation of RCS Chemistry Ts.Chemistry Sampling of Rv Coolant re-established.W/930521 Ltr ML20044E5411993-05-20020 May 1993 LER 93-009-00:on 930421,found That Design of SBGTS Would Allow Operation That Would Result in Sys Damage If Containment Venting in Progress & Experience Loca.Operating Procedures 1-OP-10 & 1-OP-24 revised.W/930520 Ltr ML20044B6761993-02-22022 February 1993 LER 93-001-00:on 930121,determined That Containment Atmospheric Control Airborne Particulate & Gaseous Radioactivity Monitors Not Seismically Qualified.Suppl to Rept Will Be submitted.W/930227 Ltr ML20029A9111991-02-25025 February 1991 LER 91-001-00:on 910125,reactor Scram Occurred During Calibr of Feedwater Computer Point.Caused by Incorrect Procedure in Summary Sheet.Maint Procedures Reviewed & revised.W/910225 Ltr ML20028H7141991-01-24024 January 1991 LER 90-019-00:on 901226,isolation Signal Caused Reactor Water Cleanup Inlet Inboard Isolation Valve to Automatically Close.Caused by de-energized HPCI Isolation Relay.Riley Scam Temp Switch Units Will Be replaced.W/910124 Ltr ML20024F7461990-12-13013 December 1990 LER 90-020-00:on 901117,primary & Secondary Containment Isolation Signals Received & Standby Gas Treatment Sys auto- Started.Caused by Scan Overload on Microprocessor.Updated Microprocessor Will Be obtained.W/901213 Ltr ML20028H0421990-09-28028 September 1990 LER 90-012-00:on 900830,Unit 2 Reactor Scram Occurred During Reactor Startup.Investigation Continuing.Level Recovered W/O Need for Safety Sys Injection & Unit Designed for Level Transient from Full power.W/900928 Ltr ML20028H0431990-09-28028 September 1990 LER 90-011-00:on 900830,RWCU Sys G31 Received Leak Hi & RWCU Leak Hi Hi Annunciators Although Actual Leak Had Not Occurred.Caused by Air in Instrument 2-G31-FT-N012 Sensing Lines.Investigation to Be conducted.W/900928 Ltr ML20043G0981990-06-15015 June 1990 LER 88-001-06:on 880102,manual Reactor Protection Sys Trip Initiated Due to Decreasing Condenser Vacuum.Cause Still Undetermined.Vendor Insp Revealed Presence of Oil Base Film in Solenoid Valves.Determination Due by 900801.W/900615 Ltr ML20043G0711990-06-13013 June 1990 LER 90-005-00:on 900514,unplanned Closure of HPCI Isolation Valve Occurred During Maint Surveillance Test.Caused by Technician Placing RCIC Instead of HPCI Test Switch to Test Position.Personnel Counseled & trained.W/900613 Ltr ML20043F6291990-06-11011 June 1990 LER 90-008-00:on 900514,HPCI Sys Rendered Inoperable When Control Power Lost to Min Flow Bypass Valve to Suppression Pool.Probably Caused by Design Problem W/Ge Model CR2940 Sockets.Light Bulb & Fuse replaced.W/900611 Ltr ML20043F6181990-06-0808 June 1990 LER 90-007-00:on 900511,identified That Damper Would Fail to Close on Loss of Power to Solenoid Valve & on 900526,damper Found Approx 30 Degrees Open.Caused by Failure of Design to Include Fail Safe Damper.Damper modified.W/900608 Ltr ML20043C9001990-06-0101 June 1990 LER 90-009-00:on 900507,determined That Tech Spec 4.6.1.1 Requirements Not Met After Performing Monthly Periodic Test 2.2.4a.Caused by Inadequate Procedure.Recommended Procedure Revs to Prevent Recurrence Being evaluated.W/900601 Ltr ML20043B7971990-05-25025 May 1990 LER 90-006-00:on 900426,hydraulic Perturbation Occurred on Variable Leg of Instrumentation Used to Sense Reactor Water Level,Causing Isolation of RWCU Sys & Initiation of Standby Gas Treatment Sys.Diaphragm Assembly recalibr.W/900525 Ltr ML20043A6121990-05-11011 May 1990 LER 90-003-01:on 900312,full Group 1 Isolation Signal Received,Resulting in Automatic Closure of Msivs.Caused by Personnel Failing to Follow Procedures.Personnel Counseled & Procedure Separated Into Two tests.W/900511 Ltr ML20012E0581990-03-23023 March 1990 LER 90-002-00:on 900224,Group I Isolation Occurred When Undervoltage Relay Replaced.Caused by Lack of Recognition of Significance of Having Turbine Reset While Performing Electro Hydraulic Control evolutions.W/900323 Ltr ML20012B8071990-03-0909 March 1990 LER 90-001-00:on 900210,determined That Core Spray Loops a & B Inoperable Due to Missed Surveillance.Cause Not Stated. Investigation continuing.W/900309 Ltr ML20012A1671990-03-0202 March 1990 LER 89-013-01:on 890909,HPCI Turbine Auxiliary Oil Pump Developed Shaft Seal Leak of Approx 1 Gpm.Caused by Failure of Shaft Seal.Root Cause of Seal Failure Initiated.Pump Seal replaced.W/900302 Ltr ML20011F5541990-02-22022 February 1990 LER 90-002-00:on 900127,common Control Bldg HVAC Sys Isolated & Transferred to Recirculation Mode as Result of Spurious Actuation of Chlorine Detector.Sensor Connection checked.W/900222 Ltr ML20006E7751990-02-19019 February 1990 LER 88-001-05:on 880102,manual Reactor Protection Sys Trip Initiated Due to Decreasing Condenser Vacuum.Caused by Numerous Leaks on Main Turbine & Main Steam Reheat Interconnecting Piping.Seating Matl installed.W/900219 Ltr ML20011F5311990-02-16016 February 1990 LER 89-026-01:on 891210,common Emergency Bus E3 Unexpectedly Deenergized,Causing Standby Gas Treatment Sys Isolation & Reactor Scram Signal.Caused by Procedural Inadequacy.Isolation Reset & Power restored.W/900216 Ltr ML20006E3681990-02-0909 February 1990 LER 88-006-02:on 880219,numerous Bolt Head Failures of 5/16- Inch X 1/2-inch Silicon Bronze Carriage Bolts Noted in Bus/ Bar Connections of Electrical Switchboards.Caused by Igscc. Bolts Replaced.Reportable Per Part 21.W/900209 Ltr ML20011E1601990-02-0101 February 1990 LER 90-001-00:on 900102,RCIC Removed from Svc & HPCI Rendered Inoperable,Placing Unit in Tech Spec 3.0.3.Caused by Personnel Error.Individual Counseled & Standing Instruction 90-003 issued.W/900201 Ltr ML19354E5651990-01-24024 January 1990 LER 89-021-00:on 891225,electrical Protection Assembly Output Breakers Associated W/Bus a of Reactor Protection Sys Tripped Open.Cause of Trip Unknown.Voltage & Frequency Output of Motor Generator a monitored.W/900124 Ltr ML19354E5611990-01-19019 January 1990 LER 89-025-00:on 891223,sample Lines for Stack Radiation Monitor Froze,Resulting in Samples Not Indicative of Ongoing Releases.Caused by Lack of Insulation on Lines Exiting Stack.Sample Lines insulated.W/900119 Ltr ML19354D8951990-01-16016 January 1990 LER 89-020-00:on 891217,relay in Reactor Protection Sys B Motor Generator Set Control Panel Burned Out,Resulting in Logic Trip of Bus B & Isolation of Standby Gas Treatment Sys.Caused by Circuit malfunction.W/900116 Ltr ML20005F0501990-01-0404 January 1990 LER 89-026-00:on 891210,loss of E3 Bus While Deenergizing Bus 2D for Scheduled Maint Occurred.Caused by Procedural Inadequacy of Plant Electric Sys Operating Procedures.Unit Reset & Sys Returned to normal.W/900104 Ltr ML20042D3551990-01-0202 January 1990 LER 89-019-00:on 891208,Group 6 Isolation Occurred W/Standby Gas Treatment Sys Auto Start During Performance of MST-SCIS21R.Caused by Inadequate Work Practices.Work Crew Counseled.Calibr Procedures May Be revised.W/900102 Ltr ML20005E3461989-12-27027 December 1989 LER 89-024-00:on 891127,17 Primary Containment Isolation Valves Not Tested Per Tech Spec Surveillance Requirement 4.6.1.1.a.Caused by Failure to Recognize Applicability of Testing.Test Rev completed.W/891227 Ltr ML20011D8411989-12-15015 December 1989 LER 89-009-01:on 890617,manual Reactor Scram Initiated Per NRC Bulletin 88-007 Due to Loss of Recirculation Pumps, Causing Loss of Offsite Power & Containment Isolation. Caused by Personnel Error.Hpci Sys secured.W/891215 Ltr ML20011D2251989-12-14014 December 1989 LER 89-023-00:on 891116,reactor Shutdown When Drywell to Suppression Chamber Vacuum Breaker Opened.Caused by Excessive Vibration & Lack of Proper Space Between Actuator Arm & Piston.Procedures Will Be revised.W/891214 Ltr ML19332E9001989-12-0707 December 1989 LER 89-022-00:on 891110,automatic Isolation of Units 1 & 2 Common Control Bldg HVAC & Emergency Air Filtration Sys Occurred.Cause Not Determined.Detectors auto-reset & Sys Returned to Normal svc.W/891207 Ltr ML19332D5791989-11-27027 November 1989 LER 89-018-00:on 891101,determined That Safety Relief Valves Did Not Actuate within Required +/- 1.0% of Setpoints.Cause Not Determined.Setpoints recertified.W/891127 Ltr ML19332C3861989-11-21021 November 1989 LER 89-021-00:on 891022,inadvertent LOCA Initiation Signal Occurred During Monthly Channel Calibr & Functional Test. Caused by Technician Miscommunication.Involved Technicians counseled.W/891121 Ltr ML19327C2021989-11-14014 November 1989 LER 89-019-01:on 890914,determined That Svc Water Sys May Not Have Met Design Requirements Under worst-case Conditions.Caused by Inadequate Component design.Cross-tie Valves Installed.Also Reported Per Part 21.W/891114 Ltr ML19324C3171989-11-0707 November 1989 LER 89-020-00:on 891011,HPCI F006 Valve Motor Control Ctr Indicating Light Socket Shorted & Blew Control Power Fuse for Valve.Caused by Inward Force Applied to Bulb During Removal.Lamp,Socket & Fuse replaced.W/891107 Ltr ML19324C1041989-11-0606 November 1989 LER 89-017-00:on 891010,low Level Signals Occurred,Causing Group 1 Isolation,Core Spray Initiation Signal & auto-start of Common Emergency Diesel Generators.Caused by Perturbation of Ref Leg.Procedures revised.W/891106 Ltr ML19327B9861989-11-0606 November 1989 LER 89-017-01:on 890624,HPCI Sys,Steam Line Break Delta Pressure High Signal,Channel A,Isolation Occurred.Root Cause Investigation Underway.Work Request/Job Order Initiated Requesting Verification of readings.W/891106 Ltr ML19354D4401989-11-0101 November 1989 LER 89-016-01:on 890614,determined That Some Valves Listed in Table 1 of LER Not Tested Per Tech Specs.Caused by Failure to Establish Proper Procedural Controls.Valve Acceptance Criteria Basis Sheets updated.W/891101 Ltr 1994-05-13
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217N3271999-10-21021 October 1999 Part 21 Rept Re non-linear Oxygen Readings with Two (2) Model 225 CMA-X Containment Monitoring Sys at Bsep.Caused by High Gain Produced by 10K Resistor Across Second Stage Amplifier.Engineering Drawings Will Be Revised BSEP-99-0168, Monthly Operating Repts for Sept 1999 for Bsep,Units 1 & 2. with1999-09-30030 September 1999 Monthly Operating Repts for Sept 1999 for Bsep,Units 1 & 2. with ML20212D0431999-08-31031 August 1999 Monthly Operating Repts for Aug 1999 for Brunswick Steam Electric Plant,Units 1 & 2 ML20210P9441999-08-10010 August 1999 Safety Evaluation Accepting Licensee Assessment of Impact on Operation of Plant,Unit 1,with Crack Indications of 2.11, 6.36 & 1.74 Inches in Three Separate Jet Pump Risers ML20210P9181999-08-10010 August 1999 Safety Evaluation Authorizing Request for Reliefs CIP-01,02, 06,07,08,09,10 & 11 (with Certain Exceptions) & 12-18,for Second 10-year ISI Interval.Request CIP-04 & 05 Would Result in hardship,CIP-03 Not Required & CIP-11 Denied in Part ML20210N2341999-08-0505 August 1999 SER Accepting Response to NRC GL 87-02, Verification of Seismic Adequacy of Mechanical & Electrical Equipment in Operating Reactors,Unresolved Safety Issues (USI) A-46 ML20210R1191999-07-31031 July 1999 Monthly Operating Repts for July 1999 for Bsep,Units 1 & 2 ML20210R1311999-06-30030 June 1999 Revised Monthly Operating Rept for June 1999 for Bsep,Unit 2 BSEP-99-0118, Monthly Operating Repts for June 1999 for Bsep,Units 1 & 2. with1999-06-30030 June 1999 Monthly Operating Repts for June 1999 for Bsep,Units 1 & 2. with BSEP-99-0095, Monthly Operating Repts for May 1999 for Brunswick Steam Electric Plant,Units 1 & 2.With1999-05-31031 May 1999 Monthly Operating Repts for May 1999 for Brunswick Steam Electric Plant,Units 1 & 2.With ML20210M8581999-05-14014 May 1999 B214R1 RPV Hydrotest Bolted Connection Corrective Action Evaluation, Rev 0 ML20211L3711999-05-10010 May 1999 Rev 0 to ESR 98-00333, Unit 2 Invessel Feedwater Sparger Evaluation ML20206G1871999-05-0404 May 1999 Safety Evaluation Approving Third 10-year ISI Program Requests for Relief (RR) RR-08,RR-15 & RR-17 BSEP-99-0075, Monthly Operating Repts for Apr 1999 for Brunswick Steam Electric Plant,Unit 1 & 2.With1999-04-30030 April 1999 Monthly Operating Repts for Apr 1999 for Brunswick Steam Electric Plant,Unit 1 & 2.With ML20206N1791999-04-23023 April 1999 Rev 0 to 2B21-0554, Brunswick Unit 2,Cycle 14 Colr BSEP-99-0059, Monthly Operating Repts for Mar 1999 for Brunswick Steam Electric Plant,Units 1 & 2.With1999-03-31031 March 1999 Monthly Operating Repts for Mar 1999 for Brunswick Steam Electric Plant,Units 1 & 2.With ML20205F9031999-03-30030 March 1999 Safety Evaluation Supporting Proposed Rev to BSEP RERP to Licenses DPR-62 & DPR-71,respectively ML20206N1831999-02-28028 February 1999 Rev 0 to Suppl Reload Licensing Rept for Bsep,Unit 2 Reload 13 Cycle 14 BSEP-99-0043, Monthly Operating Repts for Feb 1999 for Brunswick Steam Electric Plant,Units 1 & 2.With1999-02-28028 February 1999 Monthly Operating Repts for Feb 1999 for Brunswick Steam Electric Plant,Units 1 & 2.With ML20203D7061999-02-0909 February 1999 SER Accepting Proposed Alternatives Contained in Relief Requests PRR-04,VRR-04,VRR-13,PRR-01,PRR-03,VRR-01.VRR-07, VRR-08 & VRR-09 Denied BSEP-99-0005, Monthly Operating Repts for Dec 1998 for Brunswick Steam Electric Plant,Units 1 & 2.With1998-12-31031 December 1998 Monthly Operating Repts for Dec 1998 for Brunswick Steam Electric Plant,Units 1 & 2.With BSEP-98-0231, Monthly Operating Repts for Nov 1998 for Brunswick Steam Electric Plant,Units 1 & 2.With1998-11-30030 November 1998 Monthly Operating Repts for Nov 1998 for Brunswick Steam Electric Plant,Units 1 & 2.With BSEP-98-0218, Monthly Operating Repts for Oct 1998 for Bsep,Units 1 & 2. with1998-10-31031 October 1998 Monthly Operating Repts for Oct 1998 for Bsep,Units 1 & 2. with BSEP-98-0210, Special Rept:On 980824,temp Element 2-CAC-TE-1258-22 Failed. Cause of Failed Temp Element Cannot Be Conclusively Determined.Temp Element Will Be Replaced & Cable Connections Repaired1998-10-30030 October 1998 Special Rept:On 980824,temp Element 2-CAC-TE-1258-22 Failed. Cause of Failed Temp Element Cannot Be Conclusively Determined.Temp Element Will Be Replaced & Cable Connections Repaired ML20154P8151998-10-16016 October 1998 SER Accepting Revised Safety Analysis of Operational Transient of 920117,for Plant,Unit 1 ML20154P8591998-10-16016 October 1998 SER Accepting Equivalent Margins Analysis for N-16A/B Instrument Nozzles for Plant,Units 1 & 2 BSEP-98-0202, Monthly Operating Repts for Sept 1998 for Brunswick Steam Electric Plant,Units 1 & 2.With1998-09-30030 September 1998 Monthly Operating Repts for Sept 1998 for Brunswick Steam Electric Plant,Units 1 & 2.With ML20151Y6211998-09-14014 September 1998 BSEP Rept Describing Changes,Tests & Experiments, for Bsep,Units 1 & 2 ML20151Y6371998-09-14014 September 1998 Changes to QA Program, for Bsep,Units 1 & 2 BSEP-98-0185, Monthly Operating Repts for Aug 1998 for Brunswick Steam Electric Plant,Units 1 & 2.With1998-08-31031 August 1998 Monthly Operating Repts for Aug 1998 for Brunswick Steam Electric Plant,Units 1 & 2.With ML20151T5021998-08-0505 August 1998 Project Implementation Plan, Ngg Yr 2000 Readiness Program, Rev 2 BSEP-98-0164, Monthly Operating Repts for July 1998 for BSEP Units 1 & 21998-07-31031 July 1998 Monthly Operating Repts for July 1998 for BSEP Units 1 & 2 ML20236T1961998-07-0101 July 1998 Rev 1 to 2B21-0088, Brunswick Unit 2,Cycle 13 Colr ML20236T1921998-07-0101 July 1998 Rev 1 to 1B21-0537, Brunswick Unit 1,Cycle 12 Colr BSEP-98-0142, Monthly Operating Repts for June 1998 for BSEP Units 1 & 21998-06-30030 June 1998 Monthly Operating Repts for June 1998 for BSEP Units 1 & 2 ML20236T1971998-06-30030 June 1998 Rev 2 to 24A5412, Supplemental Reload Licensing Rept for Brunswick Steam Electric Plant Unit 2 Reload 12 Cycle 13 ML20249B9691998-06-11011 June 1998 Rev 1 to VC44.F02, Brunswick Steam Electric Plant,Units 1 & 2,ECCS Suction Strainers Replacement Project,Nrc Bulletin 96-003 Final Rept BSEP-98-0129, Monthly Operating Repts for May 1998 for Bsep,Units 1 & 21998-05-31031 May 1998 Monthly Operating Repts for May 1998 for Bsep,Units 1 & 2 ML20151S9041998-05-31031 May 1998 Revised Pages to Monthly Operating Rept for May 1998 for Brunswick Steam Electric Plant,Unit 1 BSEP-98-0104, Monthly Operating Repts for Apr 1998 for Brunswick Steam Electric Plant,Units 1 & 21998-04-30030 April 1998 Monthly Operating Repts for Apr 1998 for Brunswick Steam Electric Plant,Units 1 & 2 ML20151S8991998-04-30030 April 1998 Revised Pages to Monthly Operating Rept for Apr 1998 for Brunswick Steam Electric Plant,Unit 1 ML20247N7501998-04-30030 April 1998 Rev 0 to BSEP Unit 1,Cycle 12 Colr ML20247N7721998-04-30030 April 1998 Rev 0 to J1103244SRLR, Supplemental Reload Licensing Rept for BSEP Unit 1,Reload 11,Cycle 12 ML20217K8461998-04-24024 April 1998 Safety Evaluation Approving Proposed Use of Code Case N-535 at Brunswick Unit 1 During Second 10-yr Interval,Pursuant to 10CFR50.55a(a)(3)(i).Authorizes Use of Code Case N-535 Until Code Case Included in Future Rev of RG 1.147 ML20217K3941998-04-24024 April 1998 SER Approving Relief Request for Pump Vibration Monitoring, Brunswick Steam Electric Plant,Units 1 & 2 ML20217E6841998-04-23023 April 1998 Safety Evaluation Accepting Code Case N-547, Alternative Exam Requirements for Pressure Retaining Bolting of CRD Housings ML20217E7471998-04-21021 April 1998 Safety Evaluation Accepting Alternative to Insp of Reactor Pressure Vessel Circumferential Welds ML20217B5241998-04-20020 April 1998 SE Accepting Licensee Request for Approval to Use Alternative Exam Requirement for Brunswick,Unit 1,reactor Vessel Stud & Bushing During Second 10-yr ISI Interval Per 10CFR50.55a(a)(3)(ii) BSEP-98-0080, Monthly Operating Repts for Mar 1998 for Bsep,Units 1 & 21998-03-31031 March 1998 Monthly Operating Repts for Mar 1998 for Bsep,Units 1 & 2 ML20216B1041998-03-0404 March 1998 SER Approving Alternative to Insp of Reactor Pressure Vessel Circumferential Welds for Brunswick Steam Electric Plant, Unit 1 1999-09-30
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Carolina Power & Light Company
- E;acntrariawamimmante Brunswick Nuclear Plant P. O. Box 10429 Southport, N.C. 28461-0429 August 12, 1993 FILE: B09-13510C 10CFR50.73 SERIAL: BSEP-93-0128 i
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555 i
BRUNSWICK NUCLEAR PLANT UNIT 2 ,
DOCKET NO. 50-324 LICENSE NO. DRP-62 SUPPLEMENTAL LICENSEE EVENT REPORT 2-91-019-01 Gentlemen: Y In accordance with Title 10 of the Code of Federal Regulations, the enclosed -l '
Supplemental Licensee Event Report is submitted. The original report fulfilled the requirement for a written report within thirty (30) days of a reportable occurrence and was submitted in accordance with the format set forth in NUREG-1022, Septenber 1983.
Very truly yours, ,
M Wm ;
M. Brown, Plant Manager - Unit 1 )
Brunswick Nuclear Plant l l
TMJ/ ,
a Enclosure l cc: Mr. S. D. Ebneter Mr. P. D. Milano BSEP NRC Resident Office _]
l I
i 170038 .
9308170190 DR 930812
A
NRC FORM Y6 U S NUCLEAR REGULATORY COMM$SION APPROVED OMB NO 315D-0104
- EXPIRES 4/3^#92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH TH!$ INFORMATION COLLECTION REQUEST. 50 0 HRS FORWARD COMMENTS REGARDING BUR EN ESMME T THE RECORDS AND REPORTS MANAGEMENT BRANCH LICENSEE EVENT REPORT (LER) (P-630) U S NUCf. EAR REGUt ATORY COMM!SSiON, WASHINGTON, DC 20555, AND TO THE PAPERVN i:iEDUCTICN PROJECT (3150 01G4). OFFICE oF MANAGE' MENT AND BUDGET. WASHINGTON. DC 23503 F ACILITY NAME (1) Brunswick Steam Electric Plant D@C NUMMR Q PAGE (3)
Unit 2 05000324 1
mLE f4i LLRT Failure of Two Main Steam Lines' Inboard and Outboard Isolation Valves Resulting in a Condition Outside the Plant Design Basis.
EVE NT DATF (E) LER NUMBER 46) REPORT DATE (7) CTHER FACluTIES INVOLVED 19)
MONTH DAY YEAR VF AR SEQ REV NQ MONTH DAY YEAR FACILITV NAME DOCKET NUMBER NO 11 12 91 91 -
019 -
01 08 12 93 THis REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR g (Check one or mme of the followmg) (11)
OPfliATfNG MODE (9) S 20 do2?tu 20 doHci 50 73talmim) 73 71(el b
POWC R 20 4h(1gi) 50 36(n)(1) g 50 73(a) A(v) 73 71(c) }
ttvEt (10j ooo 20 4%@M SD 36(c)Q SO 73(a)Q(vu) OTHER (Specify m Abstract and Tert) 20 415[an1)(m) 50 73tajmp) $0 73(alm (vmHA)
/
20 43$(a)(1)(w) y SC 73(sjm(n) 50 73(a)Atvm)(B)
?O 4DStan(inv) 50 73(ejf2)(ni) 50 73(almb)
UCENSEE CONTACT FOR THIS LER (12)
MME Theresa M. Jones, Regulatory Compliance Specialist TELEPHONE NUMBER (919) 457-2039 COMPLETE ONE LINE FOR EACH COMPONENT F AILURE DESCRIBED IN THis REPORT (13)
GAUM SY ST EM COMPONENT MANurACTURER REPORTABLE CAUSE EYSTEM COMPONENT MANUFACTURER REPORTABLE +
TO NPRDS TO NPRDS X SB ISV R344 Y SUPPLEMENTAL PEPORT EXPECTED (14) EXPECTED MONTH DAY YEAR SUBMISSION YES pf yas cuee E@LCTED SubMtS$10N DATE)
NO DATE !
X (15) l l
ABSTRACT {Le to 1470 wees i e awmommer feean w@e um typwen imey (16) l On November 12, 1991, the Unit 2 reactor was shutdown in refuel / maintenance outage. i Local leak rate testing (LLRT) of the main steam isolation _ valves (MSIVs) had been performed. The results of testing indicated that MSIV leakage on main steam lines l (MSLs) C and D had exceeded the Technical Specification (TS) limit of 11.5 standard cubic feet per hour (scfh), but the actual amount of leakage could not be determined. MSL C outboard MSIV leakage was caused by an indication across the in-body seat. It is believed the indication resulted from the disk closing on a piece of metal that had spalled off the body bore during a previous closure. MSL C inboard MSIV leakage resulted from poor disk to in-body seat contact caused by low spots. Low spots are generally the result of in-body seat deformation from thennal expansion and contraction. It was believed that MSL D outboard MSIV leakage resulted from the disk not seating completely against the in-body seat. The disk outside diameter was contacting a raised lip (tooling mark) on the in-body seat surface. It was believed that low spots also caused leakage of the MSL D inboard valve. MSLs C and D MSIVs repairs were completed and a repeat of the testing revealed zero leakage in both MSLs (ies MSL C = 0.173 scfh and MSL D = 0.266 scfh) .
This event is considered potentially safety significant based on the inability to determine the amount of leakage. A previous failure of two MSIVs to meet the TS required 11.5 scfh leakage requirement has been reported in LER 1* SS-025, That LER involved the outboard MSIV on two separate MSLs. On December 7, 1932, the results 1 of testing indicated that MSIV leakage on MSL D had again exceeded Technical l Specification limits (LER 2-92-010).
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NRC FORM Sf4A U S NUCLEAR REGULATORY COMMISSION APPROVED OMB NO. 3150 0100
' EXP!RES: 630/02 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INWRMAN CMECM REWESt M O HRS FORWARD COMEMS LICENSEE EVENT REPORT (LER) REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS TEXT CONTINUATION MANAGEEM WNCH F53% U S NUCLEAR REGULATORY COMMISStON, WASHINGTON, DC 20555. AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104L OFFICE OF MANAGEMENT AND BUDGET. WASHINGTON, DC 20 sos IActuTV NAME (1) DOCKET NUMBER c) LER NUMBER (0) PAGE (3)
Brunswick Steam Electric Plant 05000324 vEAR SEQ REV 2 Unit 2 NO. NO 91 019 01 TExr e mm. .p.c. . r.92n.a us. .Hhonal NRC Form 3fMiA s) (17)
Title:
LLRT Failure of Two Main Steam Lines' Inboard and Outboard Isolation Valves Reeultina in a Condition Outside the Plant Desion Basis.
INITIAL CONDITIONS On Novenber 12, 1991, the Unit 2 reactor was shutdown in day 62 of the 1991 refuel / maintenance outage. Local leak rate testing (LLRT) of the main steam isolation valves (MSIVs) had been performed to satisfy technical specification (TS) primary containment leakage rate surveillance requirements. The referenced TS requires that the primary containment leakage rate be limited to less than or equal to 11.5 standard cubic feet per hour (scfh) for any one main steam line (MSL) isolation valve when tested at 25 psig.
EVENT NARRATIVE The ref erenced testing is accomplished by draining the MSL, closing the inboard and outboard MSIVs, prcasurizing the space between them to 25 psig with air while providing a vent path for any leakage, and measuring the leakage rate. In the event of a leakage rate equal to or-greater than 11.5 scfh the test procedure directs that the associated MSL be filled with water between the reactor vessel and the inboard MSIV to seal any leakage past the inboard MSIV. The space between the MSIVs is again air pressurized and the leakage rate resulting from leakage past the outboard MSIV is measured. This method of testing indicates the total MSL leakage, the leakage associated with the outbourd MSIV and, by subtraction, the leakage associated with the inboard MSIV.
The MSIVs are Rockwell Model 1612, 24", Y-type globe velves.
On September 17, 1991, the initial leakage testing of main steam lines (MSLs) C and D was conducted. In each case the line would not pressurize to the required air pressure; therefore, the amount of leakage past the outboard MSIV was nonquantifiable. Specifically, MSL C could only be pressurized to 21 psig and MSL D could not be pressurized above 3 psig.
During the testing, the test volume in MSL C experienced water intrusion but the volume in MSL D did not, indicating possible leakage of the MSL C inboard MSIV. Work requests were initiated to repair the outboard MSIVs on MSLs C and D. Inspection of the valves revealed the following:
MSL C outboard MSIV
- 1. Galled stem.
- 2. Indication on in-body seat.
- 3. Raised " lip" on in-body seat face.
- 4. Bonnet backseat deformation (indented contact pattern).
- 5. Raised metal on body bore.
MSL D outboard MSIV
- 1. Poor disk to in-body seat contact.
- 2. Disk outside diameter contacting raised " lip" on seat face above in-body seat.
- 3. Indented cont act pattern on bonnet backseat.
- 4. Steam cuts exhibited on inside diameter of packing gland / follower piece. j
.A second leakage test was performed on November 12, 1991, following repair of the MSLs C and l D outboard MSIVs. The results of these tests indicated that both outboard MSIVs were no I
1
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-)
NRO FORM 3DCA U S f(JCLEAR REGULATORY COMM$SION APPRCNED OME NO. 3150-0134 EKPIPES 413'vD2 ESTIMATED BURDEN PER RESPONSE TO COMPtY 1MTH THIS M RMAD N NECD N RE UEST. SH HRS F RWAR C MMENTS LICENSEE EVENT REPORT (LER) REGARD!NG BURDEN ESTIMATE TO THE RECORDS AND REPORTS TEXT CONTINUATION u^o^ocut"T SRAucH (R430i. u s NUCtEAR eeoutaTOR< COMM>SsiON.
WASHINGTON DC 20%5, AND TO THE PAPERWORK REDUCTION PROJECT (31500104J OFFICE OF MANAGEMENT AND BUD 3ET, WASHINGTON, DC 20503 i ActuTY NAME (1) DOCEET NUMDER (2) LER NUMBER (5) PAGE (%
Brunswick Steam Electric Plant 05000324 YEAR SEO REV 3 No- NO Unit .2 ,
91 ,
019 01 T E n %. . . . .... - -~., NRC - w .m ,
longer leaking. Given that the outboard leakage was eliminated the testing revealed that both MSLs C and D inboard MSIVs exhibited leakage. MSL C inboard MSIV was determined to have a leakage rate of 32.47 scfh. The leakage rate associated with the MSL D inboard MSIV is nonquantifiable because the test volume would not pressurize. Work requests were initiated to repair MSLs C and D inboard MSIVs. Inspection of the valves indicated the following:
fML C inboard MSIV
- 1. In-body seat showed inadequate contact with disk.
- 2. In-body seat had two small pin holes.
- 3. Contact indications on outside diameter of disk. t
- 4. Slight gall marks in body bore.
- 5. Indications on bonnet backseat.
MSL D inboard MSIV
- 1. In-body seat has two " low spots".
- 2. Gall marks on body bore.
- 3. Bonnet backseat had slight indention marks.
The MSLs C and D inboard MSIVs repairs were completed and a subsequent repeat of the testing revealed zero leakage in both MSLs (ie: MSL C = 0.173 scfh and MSL D - 0.266 scfh).
GhUSE OF EVENT A Ioot cause analysis is in progrecs and the results will be provided in a supplement to this '
report.
CORRECTIVE ACTIONS 1 MSLs C and D inboard and outboard MSIVs repairs are complete. Additional corrective actions resulting from the root cause determination will be reported in the supplement to this report.
l SAFETY ASSESSMENT This event is outside the current design basis of Unit 2. A safety assessment of this event has not been completed at this time. Available data indicates that. it is not reasonable to assume a loss of MSL or condenser integrity during a LOCA or an earthquake, therefore the MSLs and the condenser would delay the release of MSIV 3eakage. However, given that the amount of leakage which would have eccurred through MSL D MSIVs has not been quantified, the degree to which the radiological limits of 10CFR100 would have been approached during a design basis accident bas not been determined. The assessment of this event will continue and will be reported in the supplement to this report.
PREVIOUS SIMILAR EVENTS A past failure of two MSIVs to meet the TS required 11.5 scfh leakage requirement has been reported in LER 1-88-025. That LER involved the outboard MSIV on two separate MSLs.
EIIS COMPONENT IDENTIFICATION Sys t ern /Comrenent FIIS Code ;
MSIV SB/ISV l
NRCFORM 3904 U $ NUCLEAR REGULATORY COMMIS$0N APPROVED OMB NO. 31$04100 .
' EXPIRES' &sof02 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INF RMATCN C LLECTON MEST; $0.0 HRSJORWARD COMMEMS LICENSEE F. VENT REPORT (LER) REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS TEXT CONTINUATION MANWENT BRANCH N U S. NUCLEAR REGULATORY COMM:SSON, WASHlNGTON DC 205S5, AND TO THE PAPERWORK REDUCTION PROJECT (3150-01ML OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503 F ACILITY NAME tt) DOCKET NUMBER (2) LER NUMBER (e) PAGE(3)
Brunswick Steam Electric Plant 05000324 YEAR SEQ PEV 4 Unit 2 NO NO.
91 019 01 TEXT (if mme spne a reautred tme addtanal NRC Fo'm 366A e) (17)
SUPPLEMENTAL CAUSE/ CORRECTIVE ACTION ,
Q MSL C OUTBOARD MSIV The leakage of the MSL C outboard MSIV resulted from the indication across the in-body seat.
Although no foreign material was found during the inspection, it is believed the indication was caused by the disk (main disk or poppet) closing on a piece of metal that had spalled off
-the body bore during a previous closure. This conclusion was substantiated by the raised metal on the body bore. Body bore-to-disk galling is a common problem with this type of valve. Corrective actions included lapping the in-body seat to remove the indication, removing the raised lip, and honing the body bore to remove the raised metal. The bonnet backseat surface was " skim cut" to remove the deformation (indented contact pattern). The ,
raised lip on the in-body seat was determined to be a tooling mark interjected during a previous seat repair, and is not suspected to have affected valve closure. A new (lighter) disk was also installed. Installation of the lighter disk is recommended by the vendor to minimize or eliminate galling. New and improved parts (disk, stem, stem-disk, and disk-piston) being supplied by the vendor as replacements for discontinued parts are being used ,
whenever an MSIV is required to be rebuilt. Other corrective actions included installing a new stem and increasing the bonnet backseat bore inside diameter to achieve greater clearance between the stem and backseat bore. This reduces the propensity of the stem contacting the bonnet backseat during valve stroking. Also, taller spacer rings have been installed.
Taller spacer rings are less likely to become cocked and cause galling.
A possible contributor could have been leakage of the stem-disk (pilot disk) to disk-piston ,
seat due to alignment. Stem misalignment is caused by a lack of valve actuator support I resulting in actuator deflection. The vendor states that a certain amount of misalignment 2s not detrimental to the actuator performance, however it is not advisable because it may cause galling of the stem and cocking of the stem-disk. Brunswick has installed taller i spacer rings to provide additional stem support and increased the bonnet backseat bore '
internal diameter to reduce the chance of stem galling.
MSL D OUTBOARD MSIV It is believed that leakage of the MSL D outboard MSIV resulted from the disk not seating completely against the in-body seat due to the disk outside diameter coming into contact with a raised lip (tooling mark) on the in-body seat face. This was evidenced by the disk O.D.
showing signs of contacting the raised lip. Finding no indications / imperfections on either the in-body or disk seating surfaces further substantiated this analysis. The in-body seat was lapped and the tooling mark removed. A " skim cut" was performed on the bonnet backseat to remove the def ormation and the packing gland / follower was replaced. The disk was replaced and the bcnnet backseat insida diameter was enlarged. A taller spacer ring was installed.
MSL C TNPOARD M91V Leakage of the MSL C inboard MSIV is attributed to poor disk to in-body seat. contact caused by low spots. Poor or no contact in certain areas due to low spots is considered typical and a primary cause of leakage in valves. These low spots are generally the result of in-body seat deformation caused by thermal expansion and contraction. The pin holes or pits noted were not.large enough in diameter (approximately 1/32") to cause leakage. The in-body seat was lapped to a satisf actory sealing surf ace. Additional corrective actions included honing the gall marks smooth and taking a " skim cut" on the bonnet backseat to remove the indication. The disk was replaced and the bonnet backseat inside diameter enlarged. A taller spacer ring was installed.
MSL D INBOARD MSIV
, HRC FORM yiCA U 5 NOCLEAR REGULATORf COMMISSON APPROVED C#B NO 3150-0104 o . .
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'"F RMAEN MCTON REMST W HR$3ORWARD COMMENTS LICENSEE EVENT REPORT. (LER) REGARDING BUPDEN ESTIMATE TO THE RECORDS AND REPORTS TEXT CONTINUATION MANAGEMENT DRANCH (P430), U $ NUCLEAR REGULATORY COMMlSSION.
WASHINGTON DC 20%5 AND TO THE PAPERWORK REDUCTON PROJECT I (3150 010 4 OFFICE OF MANAGEMEPlf AND BUDGET, WASHINGTON, DC i "3
F AOUTY NA " - (1) DOCKET NUMBER c) LER NUMBER (6) PAGE (3)
Brunswick Steam Electric Plant 05000324 YEAR SEQ REV 5 Unit 2 NO NO 91 019 01 TEXT p ,w. we. . q,.o . . sone.:NaC rorm 3 sea .) (37; It is believed that low spots also caused leakage of the MSL D inboard valve. A loose stem-disk may have contributed to the leakage in that the disk could have cocked enough to prevent proper fit-up to the disk-piston seat. The loose stem-disk was determined to be caused by vibration loosening the locking pin (i.e., locking pin was found " wallowed outa). The in-body seat was lapped to a satisf actory sealing surf ace. The gall marks were honed smooth and .;
a " skim cut" taken to remove the indention marks from the bonnet backseat. Additionally, the' '
disk was replaced and the bonnet backseat inside diameter enlarged. A taller spacer ring was installed.
SUPPLEMENTAL SAFETY ASSESSMENT
- This event is considered potentially safety significant based on the possibility- for exceeding the 10CFR100 dose limits during a design basis accident. A dose analysis was l performed by first calculating the maximum allowable leakage without exceeding the limits and '
then the equivalent orifice necessary to produce this leakage. If the MSIV with the smallest ;
leak was more than 0.01 percent open, the offsite dose limit may have been exceeded. !
However, since the percent open la not known, the degree to which the radiological limits '
may have been approached can not be determined.
ADDITIONAL SUPPLEMENTAL INFORMATION .
t On December 7, 1992, the results of local leak rate testing indicated that MSIV leakage on MSL D again had exceeded the Techn;_al Specification limit of 11.5 scfh. Preliminary investigation indicated that the outboard MSIV appeared to have had excessive disk piston to valve bore clearance and an alignment problem (ie., the disk was not guiding properly into the in-body seat). MSLs A, B, and C tested satisfactorily. See LER 2-92-010.
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