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Category:DEFICIENCY REPORTS (PER 10CFR50.55E & PART 21)
MONTHYEARML20236P0451998-07-0808 July 1998 Part 21 Rept Re non-conformance & Potential Defect in Component of Nordberg Model FS1316HSC Standby Dg.Caused by Outer Spring Valves Mfg from Matl That Did Not Meet Specifications.Will Furnish Written Rept within 60 Days ML20198J0431997-07-28028 July 1997 Update to Amended Interim Part 21 Rept Re Harness/Positive Plate Lug Disconnect on List Ish Round Cell Battery.Requests 7-10 Day Extension to Complete Review ML20134L1081996-10-10010 October 1996 Part 21 Rept Re Defect in Component of Nordberg Model FS1316HSC Sdg.Nak Engineering,Inc Has Established & Adopted Procedures to Assemble Fuel Oil Lines & Climinate Possible Defective Condition ML20116H2031996-08-0505 August 1996 Part 21 Rept Re Potential Defect on Condition in Component of Nordberg Model FS1316HSC Sdg W/Fuel Injection Line Assembly Which Connects Fuel Pump to Injector.Caused by Loose Fuel Line Sleeve ML20086D9901995-07-0303 July 1995 Part 21 Rept Re Two Failures of Model Vtr 500 Turbochargers Supplied by Abb Turbo Systems Ltd.Failure of Turbocharger Renders Associated EDG Incapable of Providing Rated Output. Seventeen Hole Jet Assist Wall Plates Replaced ML20073S9541994-06-27027 June 1994 Part 21 Rept Re Incorrect Matl Supply Discovered on Unshipped Order.Pump Div Will Notify Enertech W/ Recommendation That Items Supplied W/Incorrect Matl Be Removed & Destroyed ML20070A1441994-06-22022 June 1994 Part 21 Rept Re Conditions Which Affect Hydraulic Valve Operators Supplied by Bw/Ip to Enertech Co & Listed Utils. Vendor Will Notify Enertech W/Recommendations That All Items Supplied W/Incorrect Matl Be Removed & Destroyed ML20126J5961992-12-31031 December 1992 Part 21 Rept Re Potential Loss of RHR Cooling During Nozzle Dam Removal.Nozzle Dams May Create Trapped Air Column Behind Cold Leg Nozzle Dam.Mod to Nozzle Dams Currently Underway. Ltrs to Affected Utils Encl ML20125C7161992-12-0707 December 1992 Part 21 Rept Re Possibility for Malfunction of Declutching Mechanisms in SMB/SB-000 & SMB/SB/SBD-00 Actuators. Malfunction Only Occurs During Seismic Event.Balanced Levers May Be Purchased from Vendor.List of Affected Utils Encl ML20127P5861992-11-23023 November 1992 Followup to 921005 Part 21 Rept Re Potential Defect in SB/SBD-1 Housing Cover Screws.Procedure Re Replacement of SBD-1 Spring Cover Bolts Encl.All Fasteners Should Be Loosened & Removed.List of Affected Utils Encl ET-NRC-92-3707, Part 21 Rept Re Degraded Performance Condition of Westinghouse Protection Sys Overtemp Delta Temp Reactor Trip Function.Issue Not Reportable,Per 10CFR21,based on Diversity of Westinghouse Protection Sys,Per WCAP-73061992-06-15015 June 1992 Part 21 Rept Re Degraded Performance Condition of Westinghouse Protection Sys Overtemp Delta Temp Reactor Trip Function.Issue Not Reportable,Per 10CFR21,based on Diversity of Westinghouse Protection Sys,Per WCAP-7306 ML20055E4831990-06-29029 June 1990 Part 21 Rept Re Defective Steam Generators Supplied by Westinghouse.Util Will Continue to Rept Any Defects or Other Info Reportable Under 10CFR21 Upon Discovery &/Or During Litigation ML20043G7641990-05-22022 May 1990 Part 21 Rept Re Potential Defect W/Speed Transmitter in Diesel Engine Control Panel of Dsrv Standby Diesel Generator.Estimate of Completion of Corrective Actions Not Possible,Since Correction Made by Other Companies ML17348A1621990-03-27027 March 1990 Part 21 Rept Re Matls W/Programmatic Defects Supplied by Dubose Steel,Inc.Customers,Purchase Order,Items & Affected Heat Numbers Listed ML19351A2941989-10-0909 October 1989 Part 21 Rept Re Potential of Ambient Compensated Molded Case Circuit Breakers to Deviate from Published Info. Instantaneous Trip Check Will Be Instituted on All Class 1E Thermal/Magnetic Ambient Breakers Prior to Shipment ML20245D9541988-09-0606 September 1988 Part 21 Rept Re Condition Involving Inconel 600 Matl Used to Fabricate Steam Generator Tube Plugs & Found to Possess Microstructure Susceptible to Stress Corrosion Cracking ML20211P7211987-02-23023 February 1987 Part 21 Rept Re Rockbestos Coaxial Cable Used in Sorrento Electronics Digital & Analog high-range Radiation Monitor. Insulation Resistance at High Temp Not High Enough for Ion Chamber & Associated Electronics to Operate Properly ML20214M3181986-09-0404 September 1986 Potential Part 21 Rept Re Contromatics Actuator W/Jackscrew/ Handwheel Emergency Override Operator.Jackscrew/Handwheel Should Be Used for Emergency Manual Operation Only.Encl Ltr Also Sent to Listed Utils/Ae Firms ML20206S0841986-06-30030 June 1986 Part 21 Rept Re Possible Cut Wires in Wire Harness of Bbc Brown Boveri K600/K800 Circuit Breakers.Initially Reported on 860509.Safety Implications Listed.Gear Guard Designed to Prevent Cut Wires ML20137K9601985-12-10010 December 1985 Part 21 Rept Re Actuators Having Only One of Required Two Springs Which Could Result in Reduction of Integrity of Reactor Coolant Boundary.Valves Supplied to McGuire Units 1 & 2 & Catawba Unit 2.Catawba Unit 2 Valve Corrected ML20127E3111985-06-19019 June 1985 Part 21 Rept Re Potential Separation of Aluminum Nameplate from Hevi-Duty Type Sbw or Szo Transformers in Nelson Electric Class 1,035-volt Motor Control Ctrs,W/Potential Short Circuit.Initially Reported on 850618 ML20101P2011984-12-26026 December 1984 Deficiency & Part 21 Rept Re Quench Cracks Discovered in Sure Loc,Inc ASME Class 2 Hex Nuts.Supplier Notified.Nuts Will Be Replaced as Necessary ML20091P6771984-06-0808 June 1984 Part 21 Rept Responding to Re QA Problems W/Hvac Equipment Mfg by Bahnson Co.Equipment Will Be Reviewed to Determine Deficiencies,Including Catawba & Oconee Air Handling Units ML20091G2071984-05-24024 May 1984 Part 21 Rept Re Bug in Detector Computer Code Resulting in Possible Miscalculation of Tech Spec Parameters for Enthalpy Rise Peaking Factor.Problem Corrected & Responsible Parties Notified ML20092P6691984-05-24024 May 1984 Potential Part 21 Rept Re Bug in Detector Computer Code for in-core Detectors.Bug Incorrectly Calculated Enthalpy Rise Peaking Factor.Bug Corrected ML20081H4801983-11-0303 November 1983 Followup to Part 21 Rept Re Potential Failure of Westinghouse Type SA-1 Relays (IE Info Notice 83-63).Addl Potential Problems Discussed in Encl Ltr Re Tantalum Capacitor Leaking Electrolyte.Not Reportable Per Part 21 ML20081K5201983-11-0101 November 1983 Followup Part 21 Rept Re Leaking Tantalum Capacitors in Class IE,SA-1 Relays (Ref IE Info Notice 83-63).Customers Given Option of Returning Relays or Performing Field Mod ML20070C7631982-12-10010 December 1982 Part 21 Rept Re Problem W/Brown Boveri Electric,Inc Low Voltage Circuit Breakers W/Solid State Trip Devices.Units from San Onofre 2 & 3 Failed Due to long-term Degradation of Filter Capacitor C205.Suspect Trip Units Should Be Tested ML20069D5471982-09-13013 September 1982 Interim Deficiency Rept Re Rotork Model NA-2 Electric Motor Switch Problems.Initially Reported on 820623.Clear Plastic Switches on Unit 1 Replaced.Unit 2 Switch Replacement Scheduled.Also Reported Per Part 21 ML20054C0861982-04-14014 April 1982 Part 21 Rept Re Airlock Door Seals Presenting Potential Safety Problem.Seals Should Not Be Used After Startup W/O Recertification.Seals Will Be Replace If Approved Test & Insp Program Cannot Be Developed ML20005B4551981-06-29029 June 1981 Part 21 Rept Re Failure of Presray Inflatable Seal Located on Personnel Air Lock.Cause Under Investigation ML19343C5071981-03-17017 March 1981 Significant Deficiency Rept 369-370/80-02 Re Steam Generator narrow-range Level Transmitter Cable Failure to Meet Environ Qualification Requirements.Cable in Unit 1 for Steam Generator Level Transmitters Replaced in Aug 1980 ML20003A3321981-01-28028 January 1981 Advises That Corrective Actions Re Significant Deficiency Repts 50-369/80-20 & 50-369/80-21 Have Been Completed for Mode 6 Sys.Remaining Sys Will Be Completed by 810301 ML20002E1481981-01-0909 January 1981 Suppl 1 to Significant Deficiency Repts SD 369/80-21 & 370/ 80-16 Re Failure to Consider Containment Vessel Dynamic Movements Due to Postulated Loca,Initially Reported 801126. Analysis Revised ML19343B8151980-12-17017 December 1980 Forwards Supplemental Response to Significant Deficiency Repts SD 369/80-18 & 370/80-13 Re Defective Coils in Valcor Solenoid Valves,Per NRC 801114 Request.Coils in Valves of Sys Required for Fuel Loading Will Be Replaced by 810109 ML19345C3341980-11-26026 November 1980 Deficiency Rept Re Improper Loads Used for Support/Restraint Design (Loca,Valve Discharge,Mismatch).Comprehensive Program Initiated to Identify Support/Restraints Affected,Revise Design Sketches & Perform Hardware Changes ML19345C4861980-11-26026 November 1980 Significant Deficiency Repts SD 369/80-21 & SD 370/80-16 Re LOCA Pressure Effects Not Considered in Analysis of Piping W/Cold Penetrations Initially Reported 801031.Comprehensive Program Initiated to Correct Problems ML19345C4851980-11-26026 November 1980 Significant Deficiency Repts SD 369/80-20 & SD 370/80-15 Re Improper Loads for Design of Pipe Support/Restraints Initially Reported 801028.Comprehensive Program Initiated to Correct Problems ML19343B4991980-11-18018 November 1980 Part 21 Rept Re Improper Operation of E-max Isolator Part Number 1750115.Single Channel Isolators 1750141 & 1750115 Will Be Changed Out W/Part 1750146 ML19343A6551980-11-14014 November 1980 Significant Deficiency Repts 369/80-19 & 370/80-14 Re Review of Piping Affecting Pipe Rupture Environ in Vital Equipment Areas.Main Steam Drain Lines Not Considered for Pipe Rupture Effects ML20002A2491980-10-30030 October 1980 SD-369/80-18 & 370/80-18:on 800930,Valcor Solenoid Valves V70900-21-3 Failed.Caused by Coil Failure Due to Incompatibility Between Polyimide Magnet Wire Insulation & Polyvinyl Butyral Binding Agent.All Coils to Be Replaced ML19344B3961980-10-10010 October 1980 Deficiency Repts SD 369/80-17 & 370/80-12 Re Improper Operation of E-max Instruments,Inc Model 175C141 Optical Isolator When Driving Loads W/Greater than 1 Amp Inrush Current.Parts Will Be Replaced W/Model 175C146 ML20008E3411980-10-0808 October 1980 Part 21 Rept Re Brand Rex Conductor.Absence of Cured Conductor Results in Unqualified Class IE Equipment. Verification of All Current & Future Components Has Been Implemented ML19338E6171980-09-26026 September 1980 Deficiency Rept Re Possible Overvoltage During Ground Faults of Potential Transformers/Cables Connected to Diesel Generators.Potential Transformers Will Be Replaced W/ phase-to-phase & open-delta Connected Transformers ML19338E0781980-09-18018 September 1980 Significant Deficiency Rept SD 369/80-15:on 800917, Pressurizer Cavity Exceeded Design Temp.Caused by Insufficient Ventilation Cooling Flow & Higher than Design Heat Loads.Permanent Temp Monitoring Sys Will Be Installed ML19331D9451980-08-28028 August 1980 Significant Deficiency Rept Re Loose Impeller Cap & Jam Nuts on RHR Pump 1A.Caused by Inadequacy of IR Recommendation Re IE Circular 79-19.Util Has Informed I-R That Recommendation Will Not Resolve Problem ML19344D9321980-08-18018 August 1980 Deficiency Rept SD 369/80-13 Re Mechanical Shock Arrestors Damaged During Installation.Arrestors Have Been Functionally Checked.Damaged Arrestors Have Been Replaced.Insp Procedures Revised to Require Functional Check ML19344E0341980-08-12012 August 1980 Suppl to Significant Deficiency Repts SD 369/80-07 & 370/80-06 Re Inadequate Min Flow Through Centifugal Charging Pumps.Westinghouse Evaluated Impact of Operating Procedure Mods.Interim Mod II Implemented for Corrective Action ML19338C6321980-08-11011 August 1980 Significant Rept SD 369/80-11 Re Valve Operator Orientation. Review of ASME Code Class 1,2 & 3 & Util Class F Valve Power Operator Orientations Revealed Several Valves Erected Outside Design Tolerances.Stds Being Revised ML19331B9491980-08-0707 August 1980 Deficiency Rept Re Defective Coil Leads on Valcor Solenoid Valves Model V70900-21-3.Vendor Insp Revealed One Valve Failed by Magnet Wire Shorting Solenoid Housing.Second Valve Start Wire Lead Joint Touching Windings.Valves Replaced 1998-07-08
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217G7951999-09-30030 September 1999 Monthly Operating Repts for Sept 1999 for McGuire Nuclear Station,Units 1 & 2 ML20217F3661999-09-22022 September 1999 Rev 18 to McGuire Unit 1 Cycle 14 Colr ML20212D1911999-09-20020 September 1999 SER Accepting Exemption from Certain Requirements of 10CFR50,App A,General Design Criterion 57 Closed System Isolation Valves for McGuire Nuclear Station,Units 1 & 2 ML20216E8851999-08-31031 August 1999 Monthly Operating Repts for Aug 1999 for McGuire Nuclear Station,Units 1 & 2 ML20211B1281999-08-31031 August 1999 Dynamic Rod Worth Measurement Using Casmo/Simulate ML20217G8101999-08-31031 August 1999 Revised Monthly Operating Repts for Aug 1999 for McGuire Nuclear Station,Unit 1 & 2 ML20211G5261999-08-24024 August 1999 SER Accepting Approval of Second 10-year Interval Inservice Insp Program Plan Request for Relief 98-004 for Plant,Unit 1 ML20211F3441999-08-17017 August 1999 Updated non-proprietary Page 2-4 of TR DPC-NE-2009 ML20210S2371999-07-31031 July 1999 Monthly Operating Repts for July 1999 for McGuire Nuclear Station,Units 1 & 2 ML20216E8951999-07-31031 July 1999 Revised Monthly Operating Repts for July 1999 for McGuire Nuclear Station,Units 1 & 2 ML20209E4361999-07-0909 July 1999 SER Agreeing with Licensee General Interpretation of TS LCO 3.0.6,but Finds No Technical Basis or Guidance That Snubbers Could Be Treated as Exception to General Interpretation ML20196K6631999-07-0707 July 1999 Safety Evaluation Supporting Licensee 990520 Position Re Inoperable Snubbers ML20209H1631999-06-30030 June 1999 Monthly Operating Repts for June 1999 for McGuire Nuclear Station,Units 1 & 2 ML20210S2491999-06-30030 June 1999 Revised Monthly Operating Rept for June 1999 for McGuire Nuclear Station,Units 1 & 2 ML20209H1731999-05-31031 May 1999 Revised Monthly Operating Rept for May 1999 for McGuire Nuclear Station,Units 1 & 2 ML20206T4771999-05-31031 May 1999 Rev 3 to UFSAR Chapter 15 Sys Transient Analysis Methodology ML20196L1881999-05-31031 May 1999 Non-proprietary Rev 1 to DPC-NE-3004, Mass & Energy Release & Containment Response Methodology ML20195K3691999-05-31031 May 1999 Monthly Operating Repts for May 1999 for McGuire Nuclear Station,Units 1 & 2 ML20206N3511999-05-11011 May 1999 Safety Evaluation Accepting Licensee Response to GL 96-05, Periodic Verification of Design-Basis Capability of Safety- Related Movs ML20195K3761999-04-30030 April 1999 Revised MORs for Apr 1999 for McGuire Nuclear Station,Units 1 & 2 ML20206R0891999-04-30030 April 1999 Monthly Operating Repts for Apr 1999 for McGuire Nuclear Station,Units 1 & 2 ML20205L2341999-04-0505 April 1999 SFP Criticality Analysis ML20206R0931999-03-31031 March 1999 Revised Monthly Repts for Mar 1999 for McGuire Nuclear Station,Units 1 & 2 ML20205P8991999-03-31031 March 1999 Monthly Operating Repts for Mar 1999 for McGuire Nuclear Station,Units 1 & 2 ML20205C4171999-03-25025 March 1999 Special Rept 99-02:on 801027,Commission Approved for publication,10CFR50.48 & 10CFR50 App R Delineating Certain Fire Protection Provisions for Nuclear Power Plants Licensed to Operate Prior to 790101.Team Draft Findings Reviewed ML20207K2051999-03-0505 March 1999 Special Rept 99-01:on 990128,DG Tripped After 2 H of Operation During Loaded Operation for Monthly Test.Caused by Several Components That Were Degraded or Had Intermittent Problems.Parts Were Replaced & Initial Run Was Performed ML20204C8911999-02-28028 February 1999 Monthly Operating Repts for Feb 1999 for McGuire Nuclear Station,Units 1 & 2 ML20205P9021999-02-28028 February 1999 Revised Monthly Operating Repts for Feb 1999 for McGuire Nuclear Station,Units 1 & 2 ML20204C8961999-01-31031 January 1999 Revised Monthly Operating Repts for Jan 1999 for McGuire Nuclear Station,Units 1 & 2 ML20199E0301998-12-31031 December 1998 Monthly Operating Repts for Dec 1998 for McGuire Nuclear Station,Units 1 & 2 ML20216F9931998-12-31031 December 1998 Piedmont Municipal Power Agency 1998 Annual Rept ML20198A4481998-12-11011 December 1998 Safety Evaluation Concluding That for Relief Request 97-004, Parts 1 & 2,ASME Code Exam Requirements Are Impractical. Request for Relief & Alternative Imposed,Granted ML20198D7561998-11-30030 November 1998 Monthly Operating Repts for Nov 1998 for McGuire Nuclear Station,Units 1 & 2 ML20199E0491998-11-30030 November 1998 Revised Monthly Operating Rept for Nov 1998 for McGuire Nuclear Station,Units 1 & 2 Re Personnel Exposure ML20199E9651998-11-24024 November 1998 Rev 1 to ATI-98-012-T005, DPC Evaluation of McGuire Unit 1 Surveillance Weld Data Credibility ML20196D4171998-11-24024 November 1998 Special Rept 98-02:on 981112,failure to Implement Fire Watches in Rooms Containing Inoperable Fire Barrier Penetrations,Was Determined.Repair of Affected Fire Barriers in Progress ML20196G0581998-11-0606 November 1998 Rev 17 to COLR Cycle 13 for McGuire Unit 1 ML20196G0761998-11-0606 November 1998 Rev 15 to COLR Cycle 12 for McGuire Unit 2 ML20198D7771998-10-31031 October 1998 Revised Monthly Operating Rept for Oct 1998 for McGuire Nuclear Station,Units 1 & 2 ML20195E5961998-10-31031 October 1998 Monthly Operating Repts for Oct 1998 for McGuire Nuclear Station,Units 1 & 2 ML20154L6251998-09-30030 September 1998 Monthly Operating Repts for Sept 1998 for McGuire Nuclear Station,Units 1 & 2 ML20195E6021998-09-30030 September 1998 Revised Monthly Operating Rept for Sept 1998 for McGuire Nuclear Station,Units 1 & 2 ML20154B4131998-09-22022 September 1998 Rev 0 to ISI Rept for McGuire Nuclear Unit 1 Twelfth Refueling Outage ML20151W3521998-09-0808 September 1998 Special Rept 98-01:on 980819,maint Could Not Be Performed on FPS Due to Isolation Boundary Leakage.Caused by Inadequate Info Provided in Fire Impairment Plan.Isolated Portion of FPS Was Returned to Svc ML20154L6321998-08-31031 August 1998 Rev 1 to MOR for Aug 1998 for McGuire Nuclear Station,Unit 1 ML20153B3741998-08-31031 August 1998 Monthly Operating Repts for Aug 1998 for McGuire Nuclear Station,Units 1 & 2 ML20236U1601998-07-31031 July 1998 Non-proprietary DPC-NE-2009, DPC W Fuel Transition Rept ML20237B2381998-07-31031 July 1998 Monthly Operating Repts for July 1998 for McGuire Nuclear Station,Units 1 & 2 ML20153B3931998-07-31031 July 1998 Revised Monthly Operating Repts for Jul 1998 for McGuire Nuclear Station,Units 1 & 2 ML20236P0451998-07-0808 July 1998 Part 21 Rept Re non-conformance & Potential Defect in Component of Nordberg Model FS1316HSC Standby Dg.Caused by Outer Spring Valves Mfg from Matl That Did Not Meet Specifications.Will Furnish Written Rept within 60 Days 1999-09-30
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8 DUKE POWER GOMPANY P.O. BOX 33180 NRC p g]! "i' "4 f j Tj, , , ,
CHARLOTTP N.O. 28242 ilALH.TUGKER TE LEPHONE vua rurnummt . (704) 373-4333 r p mix. aman emoneamon h September 13, 1982 Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303 Re: McGuire Nuclear Station, Unit 1 Docket No. 50-369
Dear Mr. O'Reilly:
Please find attached for your information a report concerning Rotork Model NA-2 electric motor operator switch problems. The problem was identified on June 15, 1982 during the pre-turnover survey on Unit 2, and was reported to the NRC as a generic problem by Rotork on June 23, 1982. This has been previously reported for Unit 2 via 10 CFR 50.55e report SD-370/82-04 which was submitted by Mr. W. O.
Parker, Jr.'s letter dated July 23, 1982. The incident was considered to be of no significance with respect to the health and safety of the public.
Very truly yours, d .- Y <e-Hal B. Tucker PBN:j fw Attachment cc: Director Records Center Office of Management and Program Analysis Institute of Nuclear Power Operations U. S. Nuclear Regulatory Commission 1820 Water Place Washington, D. C. 20555 Atlanta, Georgia 30339 Mr. P. R. Bemis Sr. Resident Inspector-NRC McGuire Nuclear Station
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DUKE POWER COMPANY McGUIRE NUCLEAR STATION INFORMATION REPORT OCCURRENCE DATE: June 15, 1982 REPORT DATE: September 13, 1982 FACILITY: McGuire Unit 1, Cornelius, NC ID ENTIF' ' TION: Rotork NA-2 Actuator Control Switch Failures DESCRIPTION: On June 15, 1982, during the pre-turnover survey (initial setup) on Unit 2, four Rotork Model NA-2 valve actuators were found to have cracked or broken motor control switches. Station personnel contacted Rotork to determine the scope of the problem and the possible solutions. Rotork responded that the cracking problem was limited to the clear plastic switches used on the NA-2 actuators. NA-2 actuators were only used on valves located outside containment. The Unit I actuators might contain defective switches as well as the Unit 2 actuators. Rotork indicated that the switches would probably fail at the end of the actuator stroke and the failure would be obvious because the motor would continue to run until the windings overheated and burned open.
Station and Rotork personnel began a survey to determine the number and condition of clear plastic switches on Unit 1 actuators on June 17, 1982. At a meeting on June 21, 1982, Rotork representatives discussed the nature of the problem with Duke personnel and recommended that all clear plastic switches be replaced with the colored plastic switches used on Rotork Model NA-1 actuators. They explained that the defec-tive switches could not be identified by part numbers or the date of manufacture of the actuators. During t he outage for eddy current testing of steam generator (S/G) tubes which began on June 24, 1982, all Unit 1 safety related valves containing NA-2 actuators were inspected, and the clear plastic switches were replaced.
Valves that were possibly affected by this incident are located in the following systems: Component Cooling, Diesel Generator Fuel Oil, Residual Heat Removal, Safety Injection, Breathing Air, Instrument Air, Chemical & Volume Control, Auxiliary Feed-water, Nuclear Service Water, Control Area Ventilation, Containment Spray, Refueling Water, Liquid Waste Recycle, Boron Recycle, Nuclear Sampling, Station Air.
Unit 1 operated at 75% power during this incident. The defective switch casings resulted from a manufacturing error. Rotork reported the generic switch problem to the NRC under 10 CFR Part 21 on June 23, 1982.
EVALUATION: The clear plastic cases used on the TK5C/1485, Burgess switches begin to crack at the stress points such as the rivets that hold the two parts of the case together or the screws that assemble the switches into three unit switch banks.
Rotork personnel at the June 21, 1982 meeting explained the failure sequence as follows. During the manufacture of the switch casings, the material is cured in a dryer. If the moisture content (humidity) is too high during this process, the j water will react with the plastic, reducing its molecular weight. If the molecular '
weight is ..ow enough, the plastic may be further weakened by its reaction with the gas giver off by the wire insulation inside the actuator.
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Information Report Srptember 13, 1982 Page 2 Switches of a similar part number received at the Rotork assembly plant were placed in a common storage area and selected randomly for use in actuators as they were assembled. This random selection has prevented the isolation of defective switches to a particular batch and identifying the actuators on which they were used. A clear plastic switch that is found in the field without cracks may or may not be defective. For this reason all suspect switches were replaced.
Seventy three of the 82 actuators checked had at least one switch bank made up of clear plastic switches. (Each actuator has two switch banks with three switches per bank. One bank reacts to opening torque and open valve position, and the other bank reacts to closing torque and the closed valve position.) Out of the 73 actuators with clear plastic switches, 26 had switches that were cracked (three of these were badly cracked). Valves on which actuators had badly cracked switches included:
Refueling Water Storage Tank to Residual Heat Removal Pump Suction; Residual Heat Removal Heat Exchanger Isolation; and Station Air System Containment Isolation.
One of the three switches in each bank is used to stop the actuator at the end of the valve stroke. These switches are actuated by the torque being produced by the motor and can also be actuated by valve position if the switch lever is placed in the limit mode. Normally closed contacts are used in these switches which means that the contacts will be closed when the switch button is not depressed by an actuating lever. The failure mode observed on the Unit 2 switches resulted in the switch contacts remaining closed. Since these contacts must open to stop the valve actuator, a switch failure would result in the actuator continuing to operate, even after the valve has reached the end of its stroke, until the motor windings failed (burned open).
A failure of this type would result in a computer alarm indicating that the valve actuator was overloaded. If the valve was being positioned to its non-safety position, it would complete the stroke, fail, and the control operators would be notified via the computer alarm, giving them the opportunity to take corrective action. If the valve was being positioned to its safety position (either by the operators or an auto-matic signal) the same thing would occur.
The second switch in the bank is used to override the torque switches during the early part of the valve stroke when the valve plug is being removed from its back or front seat. Normally open contacts are used on these switches and the observed failure mode would leave these switches open. Failure of these switches would only affect valve operation if the torque required to move the valve during the early part of the stroke exceeded the respective torque switch setting. The third switch in the bank is used for indication of valve positica (a red valve open status light, and a green valve closed status light). Failure of these switches would have no effect on valve operation but the results could be confusing to the operators. The failure of one position indication switch should be obvious to the operators because either one too many or one too few status lights would be illuminated.
None of the switches in the valve actuators mentioned above were broken when they
- were surveyed. One of more switches in the open side switch bank of the residual l heat removal heat er. changer isolation valve broke as technicians were preparing to l
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- Information Report September 13, 1982 Page 3 remove it. Failure of this switch would not have prevented the valve from opening (its safety position). The motor would have been damaged at that point, and any further manipulations would have to be done manually.
SAFETY ANALYSIS: The failure mode of the control switches was such that either the
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valve actuators would have been able to perform their safety functions, or the motors that had burned out while stroking the valves to the non-safety positions would have caused control operators to receive an overload alarm. Since no valves were found to be inoperable, the health and safety of the public were not affected.
CORRECTIVE ACTION: All of the clear plastic switches on Unit I were replaced and all clear plastic switches on Unit 2 will be replaced with Burgess, Model K5C, white plastic switches. Proper valve operation was verified by operability checks and applicable functional tests.
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