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Category:LICENSEE EVENT REPORT (SEE ALSO AO
MONTHYEARML17335A7641998-10-22022 October 1998 LER 98-004-00:on 980923,inadvertent Actuation of Efs Occurred During Surveillance Testing.Caused by Personnel Error.Personnel Involved with Event Were Counseled & Procedure Changes Were Implemented.With 981022 Ltr ML20045B3021993-06-11011 June 1993 LER 93-001-00:on 930513,discovered That One Channel of Rvlms Inoperable Since Probe Replaced in Oct 1992.On 930507, Discovered That Two Sensors in Rvlms Indicating Wet.Caused by Design Error.Wiring Polarity corrected.W/930611 Ltr ML20024H2281991-05-21021 May 1991 LER 91-003-00:on 910421,actuation of EFW Sys During Plant Heatup Occurred Due to Low Once Through Steam Generator Level.Caused by Leaking Feedwater Recirculation Valve.Plant Startup Procedure OP 1102.02 Will Be revised.W/910521 Ltr ML20024H0861991-05-10010 May 1991 LER 91-002-00:on 910410,inadvertent Actuations of Combined Control Emergency Ventilation Sys Occurred.Caused by Transient Noise Spike.Mod Will Be Completed by 910531 to Install Time Delay in Actuation circuitry.W/910510 Ltr ML20024G9781991-05-10010 May 1991 LER 90-004-01:on 900531,discovered Degraded Fire Barrier Penetration During Insp Per Generic Ltr 86-10.Caused by Failure to Identify Adequate Fire Barrier Seal During 1983 Plant Walkdown.Fire Watch posted.W/910510 Ltr ML20029C3771991-03-22022 March 1991 LER 91-006-00:on 910222,core Protection Calculator Reactor Coolant Sys Flow Channels Not Being Calibrated within Tech Spec.Caused by Personnel Error.Operations Manager Counseled Operators Involved in event.W/910322 Ltr ML20029B1331991-02-27027 February 1991 LER 91-004-00:on 910125,control Room Radiation Monitor Alarm/Trip Setpoint Greater than Normal.Caused by Personnel Error.Operations Manager Will Counsel Shift Supervisors & Night Order Will Be posted.W/910227 Ltr ML20028H6841991-01-21021 January 1991 LER 90-021-00:on 901222,potential RCS Leak Noted in Area of Pressurizer Upper Level Instrument Nozzle.Caused by Pure Water Stress Corrosion Cracking.New Nozzle Installed Into Penetration from Shell OD.W/910121 Ltr ML20043C6801990-05-31031 May 1990 LER 89-025-01:on 891221,identified That Portion of Wall Located in Auxiliary Bldg Had Not Been Previously Identified as Tech Spec Fire Barrier.Caused by Personnel Error.Wall Being Upgraded to Tech Spec status.W/900531 Ltr ML20043C3781990-05-30030 May 1990 LER 90-012-00:on 900430,18 Month Channel Calibr of Liquid Radwaste Effluent Line Flow Monitor Not Performed as Required.Caused by Inadequate Controls to Ensure Followup Actions Taken in Timely Manner.Amends revised.W/900530 Ltr ML20043C0361990-05-23023 May 1990 LER 90-003-01:on 900423,discovered That Incorrect Monitoring Instrumentation for Radiological Effluent Ventilation Sys Utilized to Comply W/Tech Specs.Caused by Mgt Oversight.Logs Process Monitors Will Not Be used.W/900523 Ltr ML20043A7411990-05-17017 May 1990 LER 90-004-01:on 900212,discovered That Backwater Valve in Floor Drain Pipe in Emergency Feedwater Pump Room Missing. Caused by Inadequate Configuration Control.Backwater Pumps Installed & Will Be Included in Maint program.W/900517 Ltr ML20042F7681990-05-0101 May 1990 LER 90-002-01:on 900131,errors Identified in Calculation Used to Establish Calibr Tables for Steam Generator Water Level Transmitters.Errors in Original Calculation Not Identified.Calibr Procedures revised.W/900501 Ltr ML20042F7751990-05-0101 May 1990 LER 90-010-00:on 900401,personnel Failed to Complete Control Element Assembly Position Log.Caused by Surveillance Program Deficiencies & Lack of Mgt Involvement.Shift Briefing Completed & Procedure Change incorporated.W/900501 Ltr ML20042E1981990-04-10010 April 1990 LER 90-008-00:on 900311,determined That Seal Leakage Test for Containment Personnel Air Lock Had Not Been Performed, Per Tech Specs.Caused by Personnel Error.Procedure Revs Initiated & Personnel counseled.W/900410 Ltr ML20012F5051990-04-0505 April 1990 LER 89-027-00:on 891005,determined That Leakage Rate for Containment Isolation Check Valve in Excess of Leakage Rate Allowed Per Tech Specs.Caused by Loose Weld Slag in Valve Seat Area.Valve Cleaned & reassembled.W/900405 Ltr ML20012F5031990-04-0505 April 1990 LER 90-007-00:on 900306,RCS Charging Line Rendered Inoperable Due to Deficient Piping Support Weld.Caused by Inadequate Work Controls & post-installation Insp Processes. Field Walkdowns & Weld Insps initiated.W/900405 Ltr ML20012F5741990-04-0404 April 1990 LER 90-006-00:on 900305,instrumentation Channels Declared Inoperable,Resulting in Manual Actuation of Reactor Protection Sys.Caused by Procedural Deficiencies.Functional Tests of Log Power Level Channels performed.W/900404 Ltr ML20012C7221990-03-14014 March 1990 LER 90-004-00:on 900212,identified That No Backwater Valve Located in Floor Drain Pipe in One of Emergency Feedwater Pump Rooms.Caused by Inadequate Configuration Control. Valves Installed on 900215.W/900314 Ltr ML20012C1821990-03-12012 March 1990 LER 85-029-00:on 850520,unusual Motor Vibrations Identified on Svc Water Pump 2PM4A.On 861028,high Vibrations Noted on Upper Motor Bearings of Pump 2PM4B.Caused by Improper Installation.New Bearings installed.W/900312 Ltr ML20012B7271990-03-0808 March 1990 LER 89-049-01:on 891220,discovered That Okonite T-95 Tape Not Used to Tape Internal Motor Lead Connections for Main Feedwater Containment Isolation Valves.Caused by Personnel Error.Valves Taped According to Design drawing.W/900308 Ltr ML20012B5701990-03-0505 March 1990 LER 90-003-00:on 900201,failure to Perform Monthly Source Check Surveillance on Three Radiation Process Monitors Occurred.Caused by Inadequate Procedure Change by Personnel. Source Check on Monthly Basis implemented.W/900305 Ltr ML20011F6741990-03-0202 March 1990 LER 90-002-00:on 900131,errors Identified in Calculation Used to Establish Calibr Tables for Steam Generator Water Level Transmitters.Caused by Incorrect Static Pressure Assumption.Trip Setpoint Bistable increased.W/900302 Ltr ML20011F6781990-03-0101 March 1990 LER 89-026-00:on 891112,gaps in Piping Supports on Supply & Return Piping for Containment Coolers Identified.Caused by Inadequate Design Technique Used in Original Support Design. Shims Added Before Restart from outage.W/900301 Ltr ML20011F5831990-02-27027 February 1990 LER 89-022-01:on 891114,normal Offsite Power Feeder Breaker to 4,160-volt Ac ESF Bus Opened,Resulting in Loss of Power to Bus 2A3.Caused by Inadequate post-maint Test Controls. Test Switch Opened & Job Order changed.W/900227 Ltr ML20011F7311990-02-23023 February 1990 LER 90-001-00:on 900126,identified That Required Visual Insps of Containment Bldg After Entry Made Not Documented as Being Performed.Caused by Inadequate Procedural Guidance. Administrative Controls to Be established.W/900226 Ltr ML20006D7391990-02-0606 February 1990 LER 89-034-01:on 891031,determined That Tech Spec 3.9.1 Had Likely Been Violated Re Independent Circuits of Control Room Emergency Air Conditioning Sys.Caused by Inadequate Guidance Re Equipment Svc Removal.Procedures revised.W/900206 Ltr ML20011E2371990-01-31031 January 1990 LER 89-012-01:on 890626,RCS Backleakage Through Safety Injection Sys Check Valve Occurred Three Times.Caused by Missing Rollpins Which Connect Valve Disc to Valve Disc Shaft.Rollpins Replaced & Valves reassembled.W/900131 Ltr ML20011E2291990-01-31031 January 1990 LER 89-039-01:on 891116,discovered That Door for Upper North Electrical Penetration Room Open & Latch Mechanism Missing. Caused by Abnormally High Differential Pressure Across Door. Ventilation Sys Flow Balance performed.W/900131 Ltr ML20011E1451990-01-30030 January 1990 LER 89-024-00:on 891231,loose Terminal in Feedwater Control Sys Cabinet Resulted in Reactor Trip.Caused by Loose Connection on Terminal.Loose Connection Reterminated properly.W/900130 Ltr ML20006C1451990-01-29029 January 1990 LER 89-048-00:on 891228,automatic Reactor Trip & ESF Actuation Occurred as Result of Loss of All Main Feedwater Flow Due to Inadvertent Tripping of Main Feedwater Pump. Caused by Personnel error.O-rings replaced.W/900129 Ltr ML19354E3331990-01-22022 January 1990 LER 89-025-00:on 891221,two Piping Penetrations Located in Barrier Not Surveilled as Required by Tech Specs.Caused by Personnel Error.Fire Watch Posted When Necessary Per Tech Spec.W/900122 Ltr ML20006A8661990-01-22022 January 1990 LER 89-041-00:on 891221,automatic Actuation of Emergency Feedwater Sys Initiated.Caused by Lack of Adequate Procedural Guidance.Valve Positioners CV-2623 & CV-2673 Adjusted & Guidance Procedures developed.W/900122 Ltr ML20006A8671990-01-22022 January 1990 LER 89-042-01:on 891209,inadvertent Actuation of Control Room Emergency Ventilation Sys Occurred.Caused by Keying of Hand Held Radio in Vicinity of Chlorine Monitors by Technician.Technician counseled.W/900122 Ltr ML20005F1551990-01-18018 January 1990 LER 89-023-01:on 891117,noted That Channel a Not Responding to Change in Power Level & Declared Inoperable.Caused by Defective Preamplifier.Evaluation of Sys Design & Channel Functional Test initiated.W/900108 Ltr ML20006B6461990-01-18018 January 1990 LER 89-047-00:on 891219,RCS Temp Increased Above 250 F W/ Oxygen Concentration Greater than Tech Specs Limit.Caused by Inadequate Procedural Guidance.Plant Startup Procedure Revised to Require Chemistry Dept signoff.W/900118 Ltr ML19354D8291990-01-15015 January 1990 LER 89-044-00:on 891214,incorrect Assumptions & Calculational Errors Identified for Low Pressure Injection & Reactor Bldg Spray Pumps When Aligned to Take Suction from Reactor Bldg sump.W/900115 Ltr ML20005G1681990-01-0909 January 1990 LER 89-045-00:on 891210,discovered That U-bolt Supports on Two Containment Isolation Valves in Containment Bldg Not Installed & Pressurizer Sample Lines & Valves Considered Inoperable.Missing U-bolts installed.W/900109 Ltr ML20005F1481990-01-0808 January 1990 LER 89-042-00:on 891209,inadvertent Actuation of Control Room Emergency Ventilation Sys Occurred.Caused by Keying of Hand Held Radio in Vicinity of Chlorine Monitors by Technician.Technician counseled.W/900108 Ltr ML20005F1571990-01-0808 January 1990 LER 89-043-00:on 891208,discovered That Approx 50% of One Nut Ring Half Beneath Reactor Vessel Nozzle Flange Corroded Away.Caused by Gradual Deterioration of Gasket Matl.Design Change implemented.W/900108 Ltr ML20005F2071990-01-0404 January 1990 LER 89-040-00:on 891205 & 06,automatic Actuations of Emergency Diesel Generator Occurred as Result of Loss of Power to 480-volt ESF Bus.Caused by Personnel Error During Bus Transfer.Mgt Briefings conducted.W/900104 Ltr ML20005F0471990-01-0303 January 1990 LER 89-046-00:on 891204,reactor Bldg Isolation Valves Rendered Inoperable Due to Deficient Welds on Piping Supports Which Were Installed During Initial Plant Const. Deficient Supports Repaired Prior to restart.W/900103 Ltr ML20011D2521989-12-18018 December 1989 LER 89-039-00:on 891116,discovered That Door for Upper North Electrical Penetration Room Open & Missing Latch Mechanism. Caused by Extensive Use During 56-day Refueling Outage.More Frequent Insps of Door Condition to Be done.W/891218 Ltr ML20011D2501989-12-18018 December 1989 LER 89-023-00:on 891117,approach to Criticality Commenced After Seventh Refueling Outage W/Logarithmic Power Level Channels Inoperable.Caused by Electrical Noise in Circuitry. Defective Preamplifier replaced.W/891218 Ltr ML19351A6731989-12-14014 December 1989 LER 89-022-00:on 891114,inadequate post-maint Test Controls Resulted in de-energizing 4,160 Volt Ac ESFs Electric Bus Uexpectedly.Caused by Inadequate post-maint Test Controls. Job Order Instructions changed.W/891214 Ltr ML19354D5521989-12-14014 December 1989 LER 89-038-00:on 891114,reactor Trip Occurred as Result of Inadvertent Closure of Main Feedwater Isolation Valve.Caused by Personnel Error.Disciplinary Action Taken Against Individual & Senior Mgt Personnel Put on shift.W/891214 Ltr ML19351A4651989-12-11011 December 1989 LER 89-021-00:on 891111,when Low Level Radwaste Water in Waste Condensate Tank Aligned to Be Released,Discovered That Radiation Monitor Inoperable for Duration of Release.Caused by Personnel Error.Procedure revised.W/891211 Ltr ML19332F6171989-12-11011 December 1989 LER 89-037-00:on 891110,reactor Trip Occurred as Result of Inadvertent Grounding of Reactor Protection Sys Power Supply During Surveillance Testing.Caused by Inadequate Procedure. Procedures revised.W/891211 Ltr ML20005D6821989-12-0101 December 1989 LER 89-005-01:on 890518 & 25,damping Board Removed from Penetration Containing Cable Tray.On 890531,voids Noted in Penetration Seals.Caused by Erroneous Vendor Procedures. Penetrations Restored & Procedures revised.W/891201 Ltr ML19332E8611989-11-30030 November 1989 LER 89-034-00:on 891031,control Room Emergency Air Conditioning Sys Rendered Inoperable Due to Removing Independent Circuits from Svc.Caused by Inadequate Guidance.Procedures Revised & Circuits flagged.W/891130 Ltr 1998-10-22
[Table view] Category:RO)
MONTHYEARML17335A7641998-10-22022 October 1998 LER 98-004-00:on 980923,inadvertent Actuation of Efs Occurred During Surveillance Testing.Caused by Personnel Error.Personnel Involved with Event Were Counseled & Procedure Changes Were Implemented.With 981022 Ltr ML20045B3021993-06-11011 June 1993 LER 93-001-00:on 930513,discovered That One Channel of Rvlms Inoperable Since Probe Replaced in Oct 1992.On 930507, Discovered That Two Sensors in Rvlms Indicating Wet.Caused by Design Error.Wiring Polarity corrected.W/930611 Ltr ML20024H2281991-05-21021 May 1991 LER 91-003-00:on 910421,actuation of EFW Sys During Plant Heatup Occurred Due to Low Once Through Steam Generator Level.Caused by Leaking Feedwater Recirculation Valve.Plant Startup Procedure OP 1102.02 Will Be revised.W/910521 Ltr ML20024H0861991-05-10010 May 1991 LER 91-002-00:on 910410,inadvertent Actuations of Combined Control Emergency Ventilation Sys Occurred.Caused by Transient Noise Spike.Mod Will Be Completed by 910531 to Install Time Delay in Actuation circuitry.W/910510 Ltr ML20024G9781991-05-10010 May 1991 LER 90-004-01:on 900531,discovered Degraded Fire Barrier Penetration During Insp Per Generic Ltr 86-10.Caused by Failure to Identify Adequate Fire Barrier Seal During 1983 Plant Walkdown.Fire Watch posted.W/910510 Ltr ML20029C3771991-03-22022 March 1991 LER 91-006-00:on 910222,core Protection Calculator Reactor Coolant Sys Flow Channels Not Being Calibrated within Tech Spec.Caused by Personnel Error.Operations Manager Counseled Operators Involved in event.W/910322 Ltr ML20029B1331991-02-27027 February 1991 LER 91-004-00:on 910125,control Room Radiation Monitor Alarm/Trip Setpoint Greater than Normal.Caused by Personnel Error.Operations Manager Will Counsel Shift Supervisors & Night Order Will Be posted.W/910227 Ltr ML20028H6841991-01-21021 January 1991 LER 90-021-00:on 901222,potential RCS Leak Noted in Area of Pressurizer Upper Level Instrument Nozzle.Caused by Pure Water Stress Corrosion Cracking.New Nozzle Installed Into Penetration from Shell OD.W/910121 Ltr ML20043C6801990-05-31031 May 1990 LER 89-025-01:on 891221,identified That Portion of Wall Located in Auxiliary Bldg Had Not Been Previously Identified as Tech Spec Fire Barrier.Caused by Personnel Error.Wall Being Upgraded to Tech Spec status.W/900531 Ltr ML20043C3781990-05-30030 May 1990 LER 90-012-00:on 900430,18 Month Channel Calibr of Liquid Radwaste Effluent Line Flow Monitor Not Performed as Required.Caused by Inadequate Controls to Ensure Followup Actions Taken in Timely Manner.Amends revised.W/900530 Ltr ML20043C0361990-05-23023 May 1990 LER 90-003-01:on 900423,discovered That Incorrect Monitoring Instrumentation for Radiological Effluent Ventilation Sys Utilized to Comply W/Tech Specs.Caused by Mgt Oversight.Logs Process Monitors Will Not Be used.W/900523 Ltr ML20043A7411990-05-17017 May 1990 LER 90-004-01:on 900212,discovered That Backwater Valve in Floor Drain Pipe in Emergency Feedwater Pump Room Missing. Caused by Inadequate Configuration Control.Backwater Pumps Installed & Will Be Included in Maint program.W/900517 Ltr ML20042F7681990-05-0101 May 1990 LER 90-002-01:on 900131,errors Identified in Calculation Used to Establish Calibr Tables for Steam Generator Water Level Transmitters.Errors in Original Calculation Not Identified.Calibr Procedures revised.W/900501 Ltr ML20042F7751990-05-0101 May 1990 LER 90-010-00:on 900401,personnel Failed to Complete Control Element Assembly Position Log.Caused by Surveillance Program Deficiencies & Lack of Mgt Involvement.Shift Briefing Completed & Procedure Change incorporated.W/900501 Ltr ML20042E1981990-04-10010 April 1990 LER 90-008-00:on 900311,determined That Seal Leakage Test for Containment Personnel Air Lock Had Not Been Performed, Per Tech Specs.Caused by Personnel Error.Procedure Revs Initiated & Personnel counseled.W/900410 Ltr ML20012F5051990-04-0505 April 1990 LER 89-027-00:on 891005,determined That Leakage Rate for Containment Isolation Check Valve in Excess of Leakage Rate Allowed Per Tech Specs.Caused by Loose Weld Slag in Valve Seat Area.Valve Cleaned & reassembled.W/900405 Ltr ML20012F5031990-04-0505 April 1990 LER 90-007-00:on 900306,RCS Charging Line Rendered Inoperable Due to Deficient Piping Support Weld.Caused by Inadequate Work Controls & post-installation Insp Processes. Field Walkdowns & Weld Insps initiated.W/900405 Ltr ML20012F5741990-04-0404 April 1990 LER 90-006-00:on 900305,instrumentation Channels Declared Inoperable,Resulting in Manual Actuation of Reactor Protection Sys.Caused by Procedural Deficiencies.Functional Tests of Log Power Level Channels performed.W/900404 Ltr ML20012C7221990-03-14014 March 1990 LER 90-004-00:on 900212,identified That No Backwater Valve Located in Floor Drain Pipe in One of Emergency Feedwater Pump Rooms.Caused by Inadequate Configuration Control. Valves Installed on 900215.W/900314 Ltr ML20012C1821990-03-12012 March 1990 LER 85-029-00:on 850520,unusual Motor Vibrations Identified on Svc Water Pump 2PM4A.On 861028,high Vibrations Noted on Upper Motor Bearings of Pump 2PM4B.Caused by Improper Installation.New Bearings installed.W/900312 Ltr ML20012B7271990-03-0808 March 1990 LER 89-049-01:on 891220,discovered That Okonite T-95 Tape Not Used to Tape Internal Motor Lead Connections for Main Feedwater Containment Isolation Valves.Caused by Personnel Error.Valves Taped According to Design drawing.W/900308 Ltr ML20012B5701990-03-0505 March 1990 LER 90-003-00:on 900201,failure to Perform Monthly Source Check Surveillance on Three Radiation Process Monitors Occurred.Caused by Inadequate Procedure Change by Personnel. Source Check on Monthly Basis implemented.W/900305 Ltr ML20011F6741990-03-0202 March 1990 LER 90-002-00:on 900131,errors Identified in Calculation Used to Establish Calibr Tables for Steam Generator Water Level Transmitters.Caused by Incorrect Static Pressure Assumption.Trip Setpoint Bistable increased.W/900302 Ltr ML20011F6781990-03-0101 March 1990 LER 89-026-00:on 891112,gaps in Piping Supports on Supply & Return Piping for Containment Coolers Identified.Caused by Inadequate Design Technique Used in Original Support Design. Shims Added Before Restart from outage.W/900301 Ltr ML20011F5831990-02-27027 February 1990 LER 89-022-01:on 891114,normal Offsite Power Feeder Breaker to 4,160-volt Ac ESF Bus Opened,Resulting in Loss of Power to Bus 2A3.Caused by Inadequate post-maint Test Controls. Test Switch Opened & Job Order changed.W/900227 Ltr ML20011F7311990-02-23023 February 1990 LER 90-001-00:on 900126,identified That Required Visual Insps of Containment Bldg After Entry Made Not Documented as Being Performed.Caused by Inadequate Procedural Guidance. Administrative Controls to Be established.W/900226 Ltr ML20006D7391990-02-0606 February 1990 LER 89-034-01:on 891031,determined That Tech Spec 3.9.1 Had Likely Been Violated Re Independent Circuits of Control Room Emergency Air Conditioning Sys.Caused by Inadequate Guidance Re Equipment Svc Removal.Procedures revised.W/900206 Ltr ML20011E2371990-01-31031 January 1990 LER 89-012-01:on 890626,RCS Backleakage Through Safety Injection Sys Check Valve Occurred Three Times.Caused by Missing Rollpins Which Connect Valve Disc to Valve Disc Shaft.Rollpins Replaced & Valves reassembled.W/900131 Ltr ML20011E2291990-01-31031 January 1990 LER 89-039-01:on 891116,discovered That Door for Upper North Electrical Penetration Room Open & Latch Mechanism Missing. Caused by Abnormally High Differential Pressure Across Door. Ventilation Sys Flow Balance performed.W/900131 Ltr ML20011E1451990-01-30030 January 1990 LER 89-024-00:on 891231,loose Terminal in Feedwater Control Sys Cabinet Resulted in Reactor Trip.Caused by Loose Connection on Terminal.Loose Connection Reterminated properly.W/900130 Ltr ML20006C1451990-01-29029 January 1990 LER 89-048-00:on 891228,automatic Reactor Trip & ESF Actuation Occurred as Result of Loss of All Main Feedwater Flow Due to Inadvertent Tripping of Main Feedwater Pump. Caused by Personnel error.O-rings replaced.W/900129 Ltr ML19354E3331990-01-22022 January 1990 LER 89-025-00:on 891221,two Piping Penetrations Located in Barrier Not Surveilled as Required by Tech Specs.Caused by Personnel Error.Fire Watch Posted When Necessary Per Tech Spec.W/900122 Ltr ML20006A8661990-01-22022 January 1990 LER 89-041-00:on 891221,automatic Actuation of Emergency Feedwater Sys Initiated.Caused by Lack of Adequate Procedural Guidance.Valve Positioners CV-2623 & CV-2673 Adjusted & Guidance Procedures developed.W/900122 Ltr ML20006A8671990-01-22022 January 1990 LER 89-042-01:on 891209,inadvertent Actuation of Control Room Emergency Ventilation Sys Occurred.Caused by Keying of Hand Held Radio in Vicinity of Chlorine Monitors by Technician.Technician counseled.W/900122 Ltr ML20005F1551990-01-18018 January 1990 LER 89-023-01:on 891117,noted That Channel a Not Responding to Change in Power Level & Declared Inoperable.Caused by Defective Preamplifier.Evaluation of Sys Design & Channel Functional Test initiated.W/900108 Ltr ML20006B6461990-01-18018 January 1990 LER 89-047-00:on 891219,RCS Temp Increased Above 250 F W/ Oxygen Concentration Greater than Tech Specs Limit.Caused by Inadequate Procedural Guidance.Plant Startup Procedure Revised to Require Chemistry Dept signoff.W/900118 Ltr ML19354D8291990-01-15015 January 1990 LER 89-044-00:on 891214,incorrect Assumptions & Calculational Errors Identified for Low Pressure Injection & Reactor Bldg Spray Pumps When Aligned to Take Suction from Reactor Bldg sump.W/900115 Ltr ML20005G1681990-01-0909 January 1990 LER 89-045-00:on 891210,discovered That U-bolt Supports on Two Containment Isolation Valves in Containment Bldg Not Installed & Pressurizer Sample Lines & Valves Considered Inoperable.Missing U-bolts installed.W/900109 Ltr ML20005F1481990-01-0808 January 1990 LER 89-042-00:on 891209,inadvertent Actuation of Control Room Emergency Ventilation Sys Occurred.Caused by Keying of Hand Held Radio in Vicinity of Chlorine Monitors by Technician.Technician counseled.W/900108 Ltr ML20005F1571990-01-0808 January 1990 LER 89-043-00:on 891208,discovered That Approx 50% of One Nut Ring Half Beneath Reactor Vessel Nozzle Flange Corroded Away.Caused by Gradual Deterioration of Gasket Matl.Design Change implemented.W/900108 Ltr ML20005F2071990-01-0404 January 1990 LER 89-040-00:on 891205 & 06,automatic Actuations of Emergency Diesel Generator Occurred as Result of Loss of Power to 480-volt ESF Bus.Caused by Personnel Error During Bus Transfer.Mgt Briefings conducted.W/900104 Ltr ML20005F0471990-01-0303 January 1990 LER 89-046-00:on 891204,reactor Bldg Isolation Valves Rendered Inoperable Due to Deficient Welds on Piping Supports Which Were Installed During Initial Plant Const. Deficient Supports Repaired Prior to restart.W/900103 Ltr ML20011D2521989-12-18018 December 1989 LER 89-039-00:on 891116,discovered That Door for Upper North Electrical Penetration Room Open & Missing Latch Mechanism. Caused by Extensive Use During 56-day Refueling Outage.More Frequent Insps of Door Condition to Be done.W/891218 Ltr ML20011D2501989-12-18018 December 1989 LER 89-023-00:on 891117,approach to Criticality Commenced After Seventh Refueling Outage W/Logarithmic Power Level Channels Inoperable.Caused by Electrical Noise in Circuitry. Defective Preamplifier replaced.W/891218 Ltr ML19351A6731989-12-14014 December 1989 LER 89-022-00:on 891114,inadequate post-maint Test Controls Resulted in de-energizing 4,160 Volt Ac ESFs Electric Bus Uexpectedly.Caused by Inadequate post-maint Test Controls. Job Order Instructions changed.W/891214 Ltr ML19354D5521989-12-14014 December 1989 LER 89-038-00:on 891114,reactor Trip Occurred as Result of Inadvertent Closure of Main Feedwater Isolation Valve.Caused by Personnel Error.Disciplinary Action Taken Against Individual & Senior Mgt Personnel Put on shift.W/891214 Ltr ML19351A4651989-12-11011 December 1989 LER 89-021-00:on 891111,when Low Level Radwaste Water in Waste Condensate Tank Aligned to Be Released,Discovered That Radiation Monitor Inoperable for Duration of Release.Caused by Personnel Error.Procedure revised.W/891211 Ltr ML19332F6171989-12-11011 December 1989 LER 89-037-00:on 891110,reactor Trip Occurred as Result of Inadvertent Grounding of Reactor Protection Sys Power Supply During Surveillance Testing.Caused by Inadequate Procedure. Procedures revised.W/891211 Ltr ML20005D6821989-12-0101 December 1989 LER 89-005-01:on 890518 & 25,damping Board Removed from Penetration Containing Cable Tray.On 890531,voids Noted in Penetration Seals.Caused by Erroneous Vendor Procedures. Penetrations Restored & Procedures revised.W/891201 Ltr ML19332E8611989-11-30030 November 1989 LER 89-034-00:on 891031,control Room Emergency Air Conditioning Sys Rendered Inoperable Due to Removing Independent Circuits from Svc.Caused by Inadequate Guidance.Procedures Revised & Circuits flagged.W/891130 Ltr 1998-10-22
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217L8931999-10-31031 October 1999 Rev 1 to BAW-10235, Mgt Program for Volumetric Outer Diameter Intergranular Attack in Tubesheets of Once-Through Sgs ML20212L1141999-10-0101 October 1999 Safety Evaluation Granting Request for Exemption from Technical Requirements of 10CFR50,App R,Section III.G.2.c 0CAN109902, Monthly Operating Repts for Sept 1999 for Arkansas Nuclear One,Units 1 & 2.With1999-09-30030 September 1999 Monthly Operating Repts for Sept 1999 for Arkansas Nuclear One,Units 1 & 2.With ML20216J6271999-09-27027 September 1999 Rev 0 to CALC-98-R-1020-04, ANO-1 Cycle 16 Colr ML20212F5261999-09-22022 September 1999 SER Approving Request Reliefs 1-98-001 & 1-98-200,parts 1,2 & 3 for Second 10-year ISI Interval at Arkansas Nuclear One, Unit 1 0CAN099907, Monthly Operating Repts for Aug 1999 for Ano,Units 1 & 2. with1999-08-31031 August 1999 Monthly Operating Repts for Aug 1999 for Ano,Units 1 & 2. with ML20211F4281999-08-25025 August 1999 Safety Evaluation Concluding That Licensee Provided Acceptable Alternative to Requirements of ASME Code Section XI & That Authorization of Proposed Alternative Would Provide Acceptable Level of Quality & Safety 0CAN089904, Monthly Operating Repts for July 1999 for Ano,Units 1 & 2. with1999-07-31031 July 1999 Monthly Operating Repts for July 1999 for Ano,Units 1 & 2. with ML20210K8831999-07-29029 July 1999 Non-proprietary Addendum B to BAW-2346P,Rev 0 Re ANO-1 Specific MSLB Leak Rates 0CAN079903, Monthly Operating Repts for June 1999 for Ano,Units 1 & 2. with1999-06-30030 June 1999 Monthly Operating Repts for June 1999 for Ano,Units 1 & 2. with ML20207E7231999-06-0202 June 1999 Safety Evaluation Authorizing Proposed Alternative Exam Methods Proposed in Alternative Exam 99-0-002 to Perform General Visual Exam of Accessible Areas & Detailed Visual Exam of Areas Determined to Be Suspect ML20196A0191999-05-31031 May 1999 Monthly Operating Repts for May 1999 for Arkansas Nuclear One,Units 1 & 2.With ML20196A6251999-05-31031 May 1999 Non-proprietary Rev 0 to TR BAW-10235, Mgt Program for Volumetric Outer Diameter Intergranular Attack in Tubesheets of Once-Through Sgs ML20195D1991999-05-28028 May 1999 Probabilistic Operational Assessment of ANO-2 SG Tubing for Cycle 14 ML20206M7711999-05-11011 May 1999 SER Accepting Relief Request from ASME Code Section XI Requirements for Plant,Units 1 & 2 0CAN059903, Monthly Operating Repts for Apr 1999 for Ano,Units 1 & 2. with1999-04-30030 April 1999 Monthly Operating Repts for Apr 1999 for Ano,Units 1 & 2. with ML20206F0691999-04-29029 April 1999 Safety Evaluation Accepting Licensee Re ISI Plan for Third 10-year Interval & Associated Requests for Alternatives for Plant,Unit 1 ML20205M6941999-04-12012 April 1999 Safety Evaluation Granting Relief for Second 10-yr Inservice Inspection Interval for Plant,Unit 1 ML20205D6061999-03-31031 March 1999 Safety Evaluation Supporting Licensee Proposed Approach Acceptable to Perform Future Structural Integrity & Operability Assessments of Carbon Steel ML20205R6351999-03-31031 March 1999 Monthly Operating Repts for Mar 1999 for Ano,Units 1 & 2. with ML20205D4711999-03-26026 March 1999 SER Accepting Util Proposed Alternative to Employ Alternative Welding Matls of Code Cases 2142-1 & 2143-1 for Reactor Coolant System to Facilitate Replacement of Steam Generators at Arkansas Nuclear One,Unit 2 ML20204B1861999-03-15015 March 1999 Safety Evaluation Authorizing Licensee Request for Alternative to Augmented Exam of Certain Reactor Vessel Shell Welds,Per Provisions of 10CFR50.55a(g)(6)(ii)(A)(5) 0CAN039904, Monthly Operating Repts for Feb 1999 for Ano,Units 1 & 2. with1999-02-28028 February 1999 Monthly Operating Repts for Feb 1999 for Ano,Units 1 & 2. with ML20212G6381999-02-25025 February 1999 Ano,Unit 2 10CFR50.59 Rept for 980411-990225 ML20203E4891999-02-11011 February 1999 Rev 1 to 97-R-2018-03, ANO-2,COLR for Cycle 14 ML20199F0351998-12-31031 December 1998 Monthly Operating Repts for Dec 1998 for Ano,Units 1 & 2 ML20198M7841998-12-29029 December 1998 SER Accepting Util Proposal to Use ASME Code Case N-578 as Alternative to ASME Code Section Xi,Table IWX-2500 for Arkansas Nuclear One,Unit 2 0CAN129805, LER 98-S02-00:on 981124,security Officer Found Not to Have Had Control of Weapon for Period of Approx 3 Minutes Due to Inadequate self-checking to Ensure That Weapon Remained Secure.All Security Officers Briefed.With1998-12-11011 December 1998 LER 98-S02-00:on 981124,security Officer Found Not to Have Had Control of Weapon for Period of Approx 3 Minutes Due to Inadequate self-checking to Ensure That Weapon Remained Secure.All Security Officers Briefed.With ML20196F4911998-12-0101 December 1998 SER Accepting Request for Relief ISI2-09 for Waterford Steam Electric Station,Unit 3 & Arkansas Nuclear One,Unit 2 ML20198D2441998-11-30030 November 1998 Monthly Operating Repts for Nov 1998 for Ano,Units 1 & 2. with ML20199F7401998-11-16016 November 1998 Rev 9 to ANO-1 Simulator Operability Test,Year 9 (First Cycle) ML20195B4801998-11-0707 November 1998 Rev 20 to ANO QA Manual Operations ML20195C4841998-11-0606 November 1998 SER Accepting QA Program Change to Consolidate Four Existing QA Programs for Arkansas Nuclear One,Grand Gulf Nuclear Station,River Bend Station & Waterford 3 Steam Electric Station Into Single QA Program 0CAN119808, Monthly Operating Repts for Oct 1998 for Ano,Units 1 & 2. with1998-10-31031 October 1998 Monthly Operating Repts for Oct 1998 for Ano,Units 1 & 2. with ML20197H0741998-10-29029 October 1998 Rev 1 to Third Interval ISI Program for ANO-1 ML20155C1351998-10-26026 October 1998 Rev B to Entergy QA Program Manual ML17335A7641998-10-22022 October 1998 LER 98-004-00:on 980923,inadvertent Actuation of Efs Occurred During Surveillance Testing.Caused by Personnel Error.Personnel Involved with Event Were Counseled & Procedure Changes Were Implemented.With 981022 Ltr ML20154J2471998-10-0909 October 1998 SER Accepting Inservice Testing Program,Third ten-year Interval for License DPR-51,Arkansas Nuclear One,Unit 1 0CAN109806, Monthly Operating Repts for Sept 1998 for ANO Units 1 & 2. with1998-09-30030 September 1998 Monthly Operating Repts for Sept 1998 for ANO Units 1 & 2. with ML20154E2171998-09-28028 September 1998 Follow-up Part 21 Rept Re Defect with 1200AC & 1200BC Recorders Built Under Westronics 10CFR50 App B Program. Westronics Has Notified Bvps,Ano & RBS & Is Currently Making Arrangements to Implement Design Mods 0CAN099803, Monthly Operating Repts for Aug 1998 for ANO Units 1 & 2. with1998-08-31031 August 1998 Monthly Operating Repts for Aug 1998 for ANO Units 1 & 2. with ML20237B7671998-08-19019 August 1998 ANO REX-98 Exercise for 980819 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 ML20236X2351998-08-0505 August 1998 Part 21 Rept Re Defect Associated W/Westronics 1200AC & 1200BC Recorders Built Under Westronics 10CFR50,App B Program.Beaver Valley,Arkansas Nuclear One & River Bend Station Notified.Design Mod Is Being Developed 0CAN089804, Monthly Operating Repts for July 1998 for Ano,Units 1 & 21998-07-31031 July 1998 Monthly Operating Repts for July 1998 for Ano,Units 1 & 2 ML20196C7831998-07-30030 July 1998 Summary Rept of Results for ASME Class 1 & 2 Pressure Retaining Components & Support for ANO-1 ML20155H7161998-07-15015 July 1998 Rev 1 to 96-R-2030-02, Revised Reactor Vessel Fluence Determination ML20236R0531998-06-30030 June 1998 Monthly Operating Repts for June 1998 for Ano,Units 1 & 2 ML20249B7791998-06-22022 June 1998 Part 21 Rept Re Findings,Resolutions & Conclusions Re Failure of Safety Related Siemens 4KV,350 MVA,1200 a Circuit Breakers to Latch Closed ML20249B5091998-06-15015 June 1998 SG ISI Results for Fourteenth Refueling Outage 1999-09-30
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L I- Arkansas Power & L';ht Company
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,i..* n. _f Atkansas Nuck *ar One Route 3 Box 137 G k ". . Russelivele. AR 72801 L Tel 501 %4 3100 L
4-
-January 8',1990 1CAN919867 e U, S. - Nuclear Regulatory Commission Document Control Desk Mail Station P1-137 Washington, D. C. ;20555
SUBJECT:
Arkansas Nu' clear One - Unit 1 Docket No. 50-313 License No. OPR-51 Licensee Event Report 50-313/89-043-00 j Gentle' men:
In accordance with 10CFR50.73(a)(2)(ii), attached is the subject report '
. concerning the boric acid corrosion of a control rod drive mechanism flange assembly caused by a deteriorated gasket which resulted in a Reactor .
Coolant System pressure boundary degradation.
Very truly yours, E. C. Ewing General. Manager, Technical Support and Assessment ECE/RHS/sgw attachment '
cc: Regional Administrator Region IV U. 5, Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76011 >
INPO Records Center 1500 Circle 75 Parkway Atlanta, GA - 30339-3064
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9001120365 900108 PDR ADOCK 05000313 S PDC An Enteg< Compaw
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'. *. Form 1062.01A
. NRC Fons 366 U.S. Nuclear Regulatory Commission ,
(9-83) Approved OsE No. 3150-0104 Expires: 8/31/85 ,
LICENSEE EVENT REPORT (L E R)
FACILITY NAME (1) Arkansas Nuclear One Unit One 100CKET NUMBER (2) IPAGE (3) 10151010101 31 11 3l110F1013 TITLE (4) Boric Acid Corrosion of a Control Rod Drive Mechanism Flange fastening Assembly caused by a Deteriorated Gasket Results in Reactor Coolant Systee Pressure Boundary Degredation
- _ EVENT DATE (5) i LER NUMBER (6) i REPORT DATE (7) 1 OTHER FACILITIES INVOLVfD (6) 1 -l l l lSequentia11. lRevisioni l 1 l l MonthI Day lYear (Year I I Number I i Number IManth! Day l Year I Facility Names h ket Number (s) l- l l l l l l l J l 1 0151010101 6 l 11 21 01 81 81 91 81 91--I 01 4! 31- I 01 01 01 11 01 81 91 01 0151010101 1 1 OPERATING I lTHIS REPORT IS SUBMITTED PURSUANT TO THE REQVIREMENTS OF 10 CFR 5:
DODE (9) l Ni (Check one or more of the followino) (13)
POWERI 1,_,,1 20.402(b) l_l 20.405(c) l_l 50.73(a)(2)(iv) l_l 73.71(b)
LEVEL l -l_ I 20.405(a)(1)(1) l l 50.36(c)(1) l_l 50.73(a)(2)(v) l_l 73.71(c)
(10) 1010101 1 20.405(h)(1){ii) l _l 50.36(c)(2)
_ l_l SC.73(a)(2)(vil) l_l Other (Specify in l_ l 20.405(a)(1)(111) l_l 50.73(a)(2)(1) 1,,,_l 50.73(a)(2)(viii)( A)1 Abstract below and I,_,1 20.405(a)(1)(iv) IJ I 50.73(a)(2)(11) l _l 50.73(a)(2)(vif1)(B)I in Text. NRC Form i I 20.405(a)(1)(v) l l 50.73(a)(2)(iii) i I 50.73(a)(2)(x) 1 366A) ;
LICENSEE CONTACT FOR THIS LER (12)
Name i Teleohone Number
- l. lArea l Larry A, Taylor, Nuclear Safety and Licensing Specialist ICode l 1510111916141-13til010 COMPLETE ONE LINE FOR EACH COMP 0NEhl FAILURE DESCRIBED IN THIS REPORT (13) l l l lReportablel 1 i l l IReportablel l- 'CauselSysteel Component lManufacturert to NPROS I ICauselsysteel Component IManufacturert to NPRDS I
.I i 1 1 1 1 l l l l 1
-I I I I I I I I I I I I I I I I i 1 1 I I I I I I l l l l l l l l l l l l 1 I i lI l i I l l I I I l l l 1 l l l l 1 1 I SUPPLEMENT REPORT EXPECTED (14) l EXPECTED l Monthi Day lYear i . .
_, 1 SUBMISSION l l 1 l
l l Yes (If yes, complete Exoected Submission Date) IXl No l DATE (15) l I I I I i l A85 TRACT (Limit to 1400 spaces, i.e. , approxteately fif teen single-space typewritten lines) (16)
[ On December 6,1989, while removing the nut ring from beneath the reactor vessel (RV) nozzle flange at Control Rod Drive Mechanism (CRDM) location L-2, plant maintenance personnel discovered that approximately 50 percent of one of the nut ring halves had corroded away and that two of the four bolt holes in the l corroded nut ring half were degraded to the point there there was no bolt / thread engagement. A total
- of six CRDM flanges had been identified to be potentially leaking during a video camera inspection on November 28, 1969 while the plant was in hot shutdown. After the plant was taken to entit shutdown, maintenance personnel disassembled and inspected the six CRDM flanges which had been identified during this inspection. All of the gasket seating surfaces were found to be undamaged with the exception of L-2. The RV nozzle flange at L-2 was eroded and pitted. An inspection of the flanges and spiral wound gaskets which were removed from between the flanges revealed that the cause of the leaks was the gradual deterioration of the caskets with age. An Engineering evaluation concluded that the L-2 nozzle flange was acceptable for use. A replacement CRDM was installed at location L-2. Additionally, the gaskets on the six CRDMs were replaced with new destyn graphite type gaskets.
l l
Form 1062.018 NRC Fom 366A - U.S. Nuclear Regulatory Commission (9-83)- Approved OMB No. 3150-0104 >
Expires: 8/31/85 LICENSEE EVfMT REPORT (LER) TEXT CONTINUATION FACILITY NAME (1) ICOCKET NLMBER (2) l LER NUISER (6) l PAGE (3) >
l l l lSequentiell IRevisioni Arkansas Nuclear One, Unit One l l Yearl ! Number Number l 10151010101 31 11 31 81 91--! 01 41 3 -- 01 Ol01210F1013 TEXT (If more space is required, use additional NRC Fom 366A's) (17)
A. Plant Status At the time of discovery of this condition, Arkansas Nuclear One Unit 1 (AND-1) was in the cold shutdown condition. Midcycle outage 1H89 was in progress.
B. Event Description On December 8, 1989, while removing the nut ring from beneath the reactor vessel (RV) nozzle flange at Control Rod Drive Mechanism (CRDM) location L-2, plant maintenance personnel discovered that approximately 50 percent of one of the nut ring halves had corroded away and that two of the four bolt holes in the corroded nut ring half were degraded to the point where there was no bolt / thread engagement.
The CROMs are attached to the RV by eight hold down bolts which pass through the CRDM flange and the RV nozzle flange and thread into a nut ring which is positioned below the RV nozzle flange.
The nut ring is a two picco carbon steel ring with four threaded holes in each section.
The disassembly of the L-2 CROM flange was baing Performed as a result of its being identified as leaking on November 28 while the plant wat in the hot shutdown condition. At that time, a video camera inspection of a RV level monitoring instrumentation (Rad Cal) flange which had been repaired j in May, 1989 was being conducted. During this inspection, a small amount of water was observed to i- be dripping from flange L-2. Upon discovery of this leak, a 100 percent inspection of the CRDM i
flanges was conducted with the video camera. Boron deposite were observeJ on five additional CRDM flanges which indicated that they could possibly have been leaking. The Red Cal flange was also observed to be leaking.
After the plant was taken to cold shutdown, maintenance personnel disassembled and inspected the flanges of the six CRDMs which had been identified as potential leakers. The location numbers of ;
these flanges are; E-5, D-8, G-9, H-8, N-8 and L-2. The RV nozzle flange at L-2 was eroded and pitted. All other inspected flanges were undamaged.
L~
l C. Safety Significance i An Engineering evaluation was conducted which determined that in its as-found condition, with two of the eight bolts carrying no load, the L-2 CRDM flange and nut ring assembly was within code allowable stress limits and would have withstood the worst case faulted condition loads. However, the ring nut assembly at L-2 was severely corroded and did represent a significant degradation of a Reactor Coolant System (RCS) [AB) pressure boundary. Had this condition gone undetected, the nut ring would have continued to corrode and could have resulted in a significant non-isolable RCS leak. It is unlikely, however, that the leak rate could have become significant without being l detected due to the various RCS leakage detection methods / systems used at ANO. During power i
operation, RCS leakage is monitored by the Inventory Balance Systee, the Reactor Building (RB)
( Sump Monitoring System, and the RB Air Monitoring System. If the total RCS leakage exceeds 10 l gallons per minute (gpe) or if unidentified RCS leakage exceeds 1 gpe, the plant's Technical Specifications require that the reactor be shut down.
In addition, prior to depressurizing in preparation for outages, and after repressurization before resuming power operativn, the RCS is inspected for leaks. This inspection includes the RV head area. Any identified R*S leaks are evaluated for boric acid corrosion effects.
D. Root Cause An inspection of the flanges and the spiral wound gaskets which were removed from between the flanges revealed that the cause of the leaks was the gradual deterioration of the gasket material with age. The gasket at L-2 had been in place since initial plant operation. The initial leakage flowpath at L-2 was across the face of the flange, down the hold down bolts and on to the carbon .
steel nut ring. This leakage flowpath had not been previously anticipated. Since the leakage did not travel to the outside edge of the flange and bewuase the nut ring area is not easily viewed, it was not detected during previous routine inspections of the RV head area. The five other CRDM flange leaks were the result of minor gasket deterioretion. The Rad Cal leak was caused by a defective seal.
7 4 O #
Form 1062.018 NRC form'366A - Lt.5. Nuclear Regulatory Commission
'(9-83) Approved OMB No. 3150-0104 Expires 8/31/85 LICENSEE EVENT REPORT (LER) TEXT CONTINUATION FACILITY NAME (1) l DOCKET NUMBER (2) l LER NUMBER (6) l PAGE (3) l l l 15equentiall IRevision!
' Arkansas Nuclear One, Unit One l l Yearl I Number l l Number l 10151010101 31 Il 31 81 91--I 01 41 31--! 01 Ol01310F1013 TEXT (If more space is required, use additional NRC Form 366A's) (17)
E. Basis For Reportability
$1nce this condition represented a significant degradation of an RCS pressure boundary, it is considered reportable pursuast to 10CFR50.73 (a)(2)(11).
This condition was also reported in accordance with 10CFR50.72 on December 12, 1989, via the Emergency Notification System.
F. Corrective Actions An Engineering evaluation was performed by Babcock and Wilcox (B&W) which concluded that, although the L-2 RV nozzle flange was eroded and pitted, it was acceptable for use. B&W is presently developing a method by which the flange can be remachined. After development of this method, the L-2 flange will be renachined during the first outage of sufficient duration. The RV dome area and the RV head bolts were visually inspected for boric acid corrosion. This inspection revealed no significant corrosion or metal loss in this area.
A design change was implemented which installed new design graphite type gaskets, which were recommended by the vendor, in the six CRDM flanges and the Red Cal flange.
A replacement CRDM was installed in location L-2. Additionally, the nut rings, bolts and washers were replaced on all six of the CRDH flanges and on the Red Cal flange, I
The defective Red Cal seal design was modified to prevent leakage.
The " Inspection and Evaluation of Boric Acid Leaks" procedure will be revised by June 15, 1990, I to require the inspectjon of the nut rings and associated hardware whenever a CRDM flange leak is identified. There are no RV head area inspections anticipated prior to this date.
The new design graphite gaskets which have been installed will be evaluated to determine if they are more reliable than the spiral wound gaskets which were originally installed. If the graphite gaskets prove to be more reliable, the spiral wound gaskets will be replaced, as necessary.
' G. Additional Information Similar events in which abnormal degradation of RCS pressure boundary components resulted from boric acid corrosion were reported in LERs 50-313/86-006-00 and 50-368/87-003-01.
Energy Industry Identification System (EIIS) codes are indicated in the text as {XX). !
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