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Issue date | Title | Topic | |
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ML20003C386 | 24 December 1973 | Ao:On 731216,during Operation at Steady Load of 734 Mw,Trip Signal Received from Main Steam Line High Flow Sensor DPIS-261-2S.Caused by Personnel Failure to Open Instrument Valve After Surveillance.Valve Opened | |
ML20083Q039 | 17 January 1973 | Ao:On 721229,electromatic Relief Valve Failed to Reset Causing Primary Sys Blowdown Following Reactor Scram.As Result,Three Different Valves Failed to Operate in Intended Manner.Manufacturers & Valve Users Will Be Consulted | Breakaway torque |
ML20084A090 | 29 October 1973 | Ao:On 730915,following Investigation of Excess Letdown Line Leak,Valve 1MOV-1299 Downstream Seat Protruded from Valve Body & Crack Discovered in Upper Portion of Downstream Seat Ring.Cause Unknown.Vendor Notified of Valve Problem | |
ML20084B712 | 26 June 1972 | Ao:On 720524,essential Svc Motor Generator Set Failed Resulting in Feedwater Control Sys Failure & Reactor Scram. Caused by Dirty Contacts on 2K Relay.Hfa Relay Replaced | |
ML20084C391 | 11 March 1974 | Telecopy Message of Ao:On 740309,drywell Equipment Drain Sump in Board Primary Containment Isolation Valve AO-2001/5 Failed to Close During Surveillance.Caused by Faulty Valve Solenoid | |
ML20084C557 | 4 October 1974 | AO 50-219/74-48:on 740925,isolation Condensers a & B Inoperable Due to High Flow as Sensed by Condensate Line Break Sensors.Caused by Tripping of Line Break Sensors Due to Effects of Rated Recirculation Flow | |
ML20084C580 | 30 September 1974 | Preliminary AO 50-219/74-48:on 740927,main Steam Line Low Pressure Switch RE23A Found to Trip at Pressure Less than Min of 860 Psig.Caused by Switch Repeatability.Ge Submitted Info to Reduce Setpoint | Fuel cladding |
ML20084C786 | 26 August 1974 | Preliminary AO 50-219/74/45:on 740824,commitment to Follow MAPLHGR Limits Violated.Caused by Insufficient Guidance. Reactor Power Reduced by Recirculation Flow to Point Where No MAPLHGR Limits Violated | |
ML20084C924 | 4 June 1974 | Suppl to Ao:On 740301,unit Diesel Tripped Due to Differential Fault.Caused by Design Failure,Allowing Improper Alignment of Fuse Clips.Fuse Clip Holder Door Modified by Adding Threetwist Locks | |
ML20084D038 | 23 June 1975 | AO 50-237/75-41:on 750613,electromatic Relief Valve 2-203-3C Failed to Operate During Test at Rated Pressure.Apparently Caused by Leaking Seal Rings in Valve.Valves Replaced by Rebuilt Valves & Successfully Tested | |
ML20084D053 | 20 June 1975 | AO 50-237/75-40:on 750611,five Arrays Exhibited 5% Scram Times Exceeding Tech Specs Limits During 2x2 Array Test. Caused by High Regulated Pressure in Scram Valve Air Header. Regulator Reset to Correct Pressure | |
ML20084D119 | 13 April 1976 | AO 50-237/75-39A:on 750612,diesel Generator Experienced Starting Failures.Possibly Caused by Two Gouged & Burred Areas on Ring Gear.Ring Gear Repaired | |
ML20084D141 | 18 June 1975 | AO 50-237/75-39:on 750612,diesel Generator Failed to Start During Surveillance Run.Cause Not Known.Suitable Action to Be Taken When Cause Determined | |
ML20084D154 | 14 January 1976 | AO 50-237/75-38A Supplementing AO-50-237/75-38 Re Failure of MO-2-1301-2 Valve to Operate.Apparently Caused by Excessive Cycling of Valve.Valve Stem Probably Experienced Metal Fatigue Due to Multiple Actuations | |
ML20084D177 | 25 June 1975 | AO 50-237/75-58:on 750615,isolation Condensor Outboard Steam Supply Valve MO-2-1301-2 Found W/Bent Stem.Possibly Caused by Combination of Excessive Cycling of Valve 1301-2 & Maladjustment of Limit Switches for Valve Travel | |
ML20084D191 | 13 June 1975 | AO 50-237/75-37:on 750604,diesel Generator Failed to Start on First Attempt.Cause Undetermined.Suitable Action Will Be Taken When Cause Determined | |
ML20084D211 | 3 July 1975 | AO 50-237/75-36:on 750606,MSIV-1C 10% Closure Limit Switch Failed.Caused by de-energized 10% Closure Relay.Switch Reassembled W/Less Torque Applied to Switch Contact Assembly Screws.Switch Operated Successfully | |
ML20084D216 | 5 June 1975 | AO 50-237/75-35:on 750526,explosion Occurred in B Offgas Sys.Cause Not Determined.Load Drop to Minimize Releases Into Bldg Started | |
ML20084D221 | 5 June 1975 | AO 50-237/75-33:on 750526,torus Level Found to Be Low.Caused by Personnel Error.Water Pumped from Condensate Storage Into Torus Via HPCI Min Flow Line.Importance of Card Tagging Procedures Emphasized | |
ML20084D225 | 3 June 1975 | AO 50-237/75-32:on 750526,electromagnetic Relief Valve 203-3B Failed to Open During post-maint Testing of Valves. Cause Unknown.Corrective Actions to Be Determined When Cause Discovered | |
ML20084D239 | 12 April 1974 | Preliminary AO 50-219/74/26:on 740412,emergency Svc Water Pump 52C Failed to Start.Cause Under Investigation | |
ML20084D378 | 23 May 1975 | AO 50-237/75-25:on 750116,Noshua Silver Duct Tape Dropped Into Reactor Vessel Annulus from Feedwater Sparger Work Platform.On 750516,decision Made to Start Reactor W/O Recovering Tape Rendering Tape Drop Reportable | |
ML20084D412 | 30 May 1975 | AO 50-237/75-31:on 750522,containment Cooling Svc Water Valve MO-1501-3A Failed to Control Flow During Scheduled Surverillance.Cause Not Determined.Design Mods for Valves Being Evaluated | |
ML20084D427 | 30 May 1975 | Ao:On 750520,electromagnetic Relief Valve 2-203-3C Failed to Open During Scheduled Surveillance.Caused by Adjustment Problem in Pilot Valve Linkage.Capscrew Out of Adjustment. All Electromagnetic Relief Valves Adjusted | |
ML20084D432 | 29 May 1975 | AO 50-237/75-29:on 750519,limit Switch Indicating 10% Closure on 1C MSIV Failed During Startup.Caused by Failure to Reinstall 1C Limit Switch & to Perform Tests.Switch Reinstalled | |
ML20084D441 | 23 May 1975 | AO 50-237/75-28:on 750506,containment Cooling Svc Water Valves MO-1501-3A & 3B Failed to Control Flow During Lpci/ Containment Cooling Logic Test.Caused by Bent Valve Stems. Increased Size Stem Valves on Order | |
ML20084D660 | 11 December 1970 | Ao:On 701204,MSIVs 1D,2A,2B & 2C Failed to Close During Biweekly Surveillance Testing.Caused by Out of Step Recorder Indexing Mechanism.Recorder Repaired.Thin Film Found on Pilot Valves.Valves Cleaned | |
ML20084D881 | 27 May 1975 | AO 50-237/75-27:on 750421,control Rod Withdrawn for Friction Testing While Both GE & Util Employees within Direct Line of Sight of Core.Caused by Disregard of Master Procedure & Failure of Testing Procedure to Include Precaution | |
ML20084D883 | 23 May 1975 | AO 50-237/75-26:on 750415,diesel Generator Starting Air Motors Failed to Start Diesel Engine.Caused by Motor Pinion Gears Jamming Against Teeth of Ring Gear Preventing Proper Engagement.Vendor Suggested Mod to Regulate Pressure | |
ML20084D888 | 21 May 1975 | AO 50-237/75-34:on 750513,drywell Equipment Drain Sump Pump Discharge Valve AO-2001-5 Failed to Close.Possibly Caused by Dirt on Solenoid Diaphragms.Valve Disassembled & Cleaned & Electric Conduit Insulation Repaired | |
ML20084E043 | 21 May 1975 | AO 50-237/75-23:on 750511,diesel Generator Overheated After Inadvertent Fast Start & ECCS Inadvertently Initiated. Overheating Caused by Loss of Cooling Water Pump Suction. ECCS Initiation Caused by Valving Out Flow Check Valve | |
ML20084E046 | 3 July 1975 | AO 50-237/75-22:on 750507,vol Bounded by Valves 2-301-98 & 2-301-99 Exceeded Max Allowable Limits During Local Leak Rate Testing.Caused by Dirty Mating Surfaces of Disc & Seat. Seating Surfaces Cleaned & Valve Returned to Svc | |
ML20084E048 | 24 April 1975 | AO 50-237/75-21:on 750416,freon Leak Rate Test on Standby Gas Treatment Sys Showed Leakage Rate Past Charcoal Cells Exceeded Tech Spec Limits.Caused by Ripped Sealing Gasket on Charcoal Cell.Torn Gasket Replaced & Cell Reinstalled | |
ML20084E049 | 16 April 1975 | Telecopy Ao:On 750416,iodine Removal Efficiency of 2/3A Standby Gas Treatment Sys Charcoal Filters Found to Be Less Efficient than Required.No Cause Stated | |
ML20084E051 | 15 April 1975 | AO 50-237/75-20:on 750405,diesel Generator Failed to Field Flash When Started.Caused by Shorted Capacitor.Capacitor Replaced | |
ML20084E053 | 31 March 1975 | AO 50-237/75-19:on 750321,secondary Containment Integrity Violated for 3 Minutes.Caused by Misunderstanding Between Security Guard & Shift Foreman.Guard Staff to Be Informed of Problems | |
ML20084E055 | 27 March 1975 | AO 50-237/75-18:on 750319,diesel Generator Failed to Come Up to Voltage During Testing.Caused by Dirty Contacts on Vs Relay in Field Flashing Circuit of Diesel Generator.Contacts Cleaned & Started Successfully | |
ML20084E062 | 27 March 1975 | AO 50-237/75-17:on 750317,main Steam Line Low Pressure Switches 261-30A-D Found to Have Low Trip Setpoints.Caused by Instrument Drift.Switch Setpoints Readjusted | |
ML20084E063 | 27 March 1975 | AO 50-237/75-16:on 750317,diesel Generator Failed to Start. Caused by Failure of Pinion Gears to Engage Ring Gear. Problem Appears to Be in Gear Mfg | |
ML20084E236 | 12 March 1975 | AO 50-237/75-14:on 750303,crack Found in Weld Between Lines 8503-8 & 1604-18.Caused by Poor Welding Technique.Weld to Be Ground Out & Pipe Reinstalled w/100% Fillet Weld | |
ML20084E248 | 10 March 1975 | AO 50-237/75-13:on 750228,motor Operated Valve 2-1402-24A on Core Spray Sys Failed to Open on Signal from Control Room. Apparently Caused by Interlocking of Valves Rendering Valve Incapable of Being Manually Opened | |
ML20084E252 | 7 April 1975 | Rev to AO Re Core Spray Injection Line through-wall Cracks. Proper Locations of Crack Indications in Error on Drawings. Correct Drawings Encl | |
ML20084E259 | 21 February 1975 | AO 50-237/75-12:on 750209,through-wall Crack Discovered on Line 2-1403-10-A (Core Spray Injection Line to Reactor Vessel).Cause Unknown.Corrective Action Will Be Based on Cause | Time of Discovery |
ML20084E363 | 29 June 1976 | Supplemental AO 50-237/75-11A:on 750127,core Spray Injection Line through-wall Cracks Discovered.Stainless Steel Portion of Core Spray Piping from Vessel Nozzle to Second Isolation Valve Replaced w/SA-333 Grade 6 Carbon Steel | |
ML20084E393 | 3 February 1975 | AO 50-237/75-10:on 750125,two Adjacent Control Blades Inadvertently Withdrawn to Position 48 During Control Rod Drive Overhaul.Caused by Temporary Procedure Change.Nuclear Engineers to Review Procedures Re Control Rod Movement | Shutdown Margin |
ML20084E432 | 7 January 1974 | AO 50-237/74-81:on 741228,relay as 284 Failed to Energize After Completion of Jumper Installation.Caused by Improper Installation of Jumper.Relay Replaced.Jumper Reinstalled Properly | |
ML20084E851 | 5 October 1970 | Telecopy Ao:On 701004,gape Valve 852B Only Opened Halfway. Caused by Loose Stem Nut of Limitorque Operator.Nut Replaced | |
ML20084E863 | 14 October 1970 | Telecopy Message of Ao:On 701014,gate Valve 851A Failed to Fully Close.Caused by Loose Stem Nut Locking.Lock Tightened & Stem Lubricated | |
ML20084K018 | 31 October 1974 | AO 50-237/1974-54:on 741022,leak Detected on Gland Leakoff Line for Valve 2-1201-99A.Caused by Improperly Welded Joint. Old Elbow Joint & Stainless Steel Line Replaced Using Approved Welding Technique | |
ML20084K046 | 31 October 1974 | AO 50-237/1974-53:on 741021,insp of Berger-Paterson Shock Suppressors Revealed Four Snubbers Low on Oil & Two Inoperable.Probably Caused by Seal Deterioration.Snubbers Will Be Replaced | Earthquake |