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| Issue date | Title | Topic | |
|---|---|---|---|
| ML20086G270 | 8 January 1976 | AO 75-79:on 751229,local Leak Test Identified through- Leakage of B Loop RHR Torus Spray Valve MO-3-10-38B & Torus Cooling Return Valve MO-3-10-34B.Cause Under Investigation | |
| ML20086G272 | 5 January 1976 | AO 75-78:on 751226,drywell Radiation Monitor Inoperative. Caused by Flow Blockage in on Stream Sample Line.Sample Point Changed to Reestablish Sample Flow to Drywell Radiation Monitor | |
| ML20086G274 | 30 December 1975 | AO 75-76:on 751220-21,local Leak Rate Test Identified through-leakage on Loop a & B RHR Outboard Injection Valves MO-3-10-154A & B.Cause Not Determined.Inboard Isolation Valves Verified as Leaktight & Closed | |
| ML19343C218 | 23 December 1975 | AO 50-219/75-33:on 751212,during 6-month Load Test on Station a batteries,125 Volt Dc Distribution Ctr de-energized.Caused by Personnel Error in Following Procedure.Distribution Ctr re-energized | |
| ML20090C999 | 12 December 1975 | AO 75-33:on 751212,125-volt Dc Distribution Ctr of Station a Battery Inadvertently de-energized.Caused by Failure to Establish Proper Breaker Lineup Preparation for Conducting Battery Load Test.Procedure changed.W/751219 Memo | |
| ML19343C219 | 11 December 1975 | AO 50-219/75-32:on 751203,during Testing,Emergency Diesel Generator 1 Failed to Start When Simulated Loss of Power Condition Applied to Fast Start Logic Circuit.Caused by Failure of Relay to Operate Due to Varnish on Armature | |
| ML20086H041 | 5 December 1975 | AO 75-72:on 751126,core Spray 3A Full Flow Test Valve MO-3-14-26A Failed to Close.Caused by Broken Wire on Closing Torque Switch in Valve Operator.Broken Wire Repaired & Proper Valve Operator Verified | |
| ML20086F843 | 5 December 1975 | AO 75-77:on 751126,LS-4223 Failed to Operate RHR Head Spray Line High Point Vent SV-4223 on Low Accumulator Level.Caused by Blown Fuse in Solenoid Valve Circuit.Grounded Wire Repaired & Vent Valve Returned to Svc | |
| ML20126E828 | 3 December 1975 | AO 50-219/75-31:on 751124,during Operability Test of Torus to Drywell Vacuum Breakers,Alarm Sys 2 Failed to Annunciate in Control Room When V-26-4 Opened.Caused by Failure of Relay Due to Contacts Being Detective.Relay Replaced | |
| ML20086F849 | 1 December 1975 | Telecopy AO 75-77:on 751126,LS-4223 Failed to Operate SV-4223 on Low Accumulator Level.Caused by Blown Fuse in Solenoid Valve Circuit.Operator Manually Vented Accumulator to Ensure Head Spray Line Maintained Filled | |
| ML20086H046 | 26 November 1975 | Telecopy AO 75-72:on 751126,core Spray Full Flow Test Valve MO-3-14-26A Failed to Close.Caused by Broken Wire on Closing Torque Switch in Valve Operator.Broken Wire Repaired & Proper Valve Operation Verified | |
| ML20086F855 | 26 November 1975 | AO 75-76:on 751117,rigid Pipe Support Found Broken on RHR Shutdown Cooling Suction Line.Caused by Component Failure. Pipe Support Replaced.Investigation Continuing | |
| ML20086F871 | 26 November 1975 | AO 75-75:on 751117,reservoirs of Two Hydraulic Snubbers Found Empty.Caused by Leaking O-rings & Gaskets.Defective gaskets,seals,O-rings & Fittings Will Be Replaced & Snubbers Will Be Checked | |
| ML20086F880 | 26 November 1975 | AO 75-74:on 751116,setpoint of RCIC Steam Supply Line Area High Temp Switch TE-TS 4939A Found Less Conservative than Specified by Tech Specs.Caused by Slight Setpoint Drift. Switch Recalibr,Tested & Returned to Svc | |
| ML20090D007 | 25 November 1975 | AO 75-31:on 751124,drywell Vacuum Breaker Alarm Sys II Failed to Annunciate When Vacuum Breaker V-26-4 Opened. Caused by Component Failure.Corrective Action Under Investigation | |
| ML20086F896 | 21 November 1975 | AO 75-73:on 751113,leak Observed on RHR Sys Relief Valve RV-35B.Caused by Throttling of MO-2-10-154B Valve Resulting in Crack.Weld Repairs Will Be Made to Relief Valve in Accordance W/Approved Procedures | |
| ML20086F861 | 18 November 1975 | Telecopy AO 75-76:on 751117,rigid Pipe Support Found Broken on RHR Shutdown Cooling Suction Line.Cause Under Investigation.Corrective Action to Be Determined After Investigation | |
| ML20086F874 | 18 November 1975 | Telecopy AO 75-75:on 751117,two Outside Drywell Snubbers Found to Have Empty Reservoirs.Cause Under Investigation. Corrective Action to Be Determined After Investigation | |
| ML20086F906 | 17 November 1975 | AO 75-71:on 751107,cracked Weld on 1-inch Line to Relief Valve RV-35B Observed.Caused by Throttling MO-2-10-154B Resulting in Cracked Weld.Repairs Completed in Accordance W/Approved Procedure | |
| ML20086F890 | 17 November 1975 | Telecopy AO 75-74:on 751116,setpoint of RCIC Steam Supply Line High Temp Switch TE-TS 4939A Found Less Conservative than Allowed by Tech Specs.Caused by Slight Setpoint Drift. Switch Recalibr & Returned to Svc | |
| ML20086F918 | 14 November 1975 | AO 75-70:on 751104,reservoirs of Five Hydraulic Snubbers Found Empty.Caused by Leaking O-rings & Gaskets.Defective Gaskets & O-rings Will Be Replaced | |
| ML20086F902 | 14 November 1975 | Telecopy AO 75-73:on 751113,leak on Body of RV-35B RHR Sys Relief Valve Observed.Caused by Throttling of MO-2-10-154B Valve Resulting in Crack.Rhr Loop B Shut Down in Preparation for Repair of Relief Valve | |
| ML20086F911 | 10 November 1975 | Telecopy AO 75-71:on 751107,cracked Weld on Line to RV-35B Observed.Caused by Throttling Down on MO-2-10-154B Resulting in Weld Crack.Repairs Completed.Pipe Vibration Readings Taken to Determine If Mods Required | |
| ML20086H052 | 7 November 1975 | AO 75-71:on 751030,drywell Oxygen Analyzer Sample Sys Outer Isolation Valve SV-3978B Failed.Caused by Dirt on Seat & in Body of Valve.Valve Internals & Seat Cleaned.Valve Disc, Piston Rings & Bonnet O-ring Replaced | |
| ML20090D016 | 7 November 1975 | AO 75-30:on 751106,low Reactor Pressure Core Spray Valve Permissive Pressure Switches Re 17 a & C Tripped at Pressure Less than Min Required Value.Caused by Switch Repeatability.Pressure Switches Recalibr | |
| ML20090D060 | 6 November 1975 | AO 75-29:on 751027,torus Drywell Vacuum Breakers Alarm Sys II Failed to Annunciate When Vacuum Breaker V-26-8 Opened. Caused by Sticking Microswitch | |
| ML20086F923 | 5 November 1975 | Telecopy AO 75-70:on 751104,reservoirs of Five Hydraulic Snubbers Found Empty.Cause Under Investigation.Corrective Action to Be Determined After Investigation | |
| ML20086H062 | 3 November 1975 | AO 75-70:on 751024,drywell Purge Supply Isolation Valve A0-3520 Operated W/O Manual Initiation.Caused by Incorrect Implementation of Mod.Piping Corrected & Will Be Monitored | |
| ML20086H075 | 31 October 1975 | AO 75-68:on 751021,torus Makeup Supply Isolation Valve AO-3523 Found to Leak in Excess of 2,000 Cc/Minute.Caused by Closing Spring Not Providing Sufficient Force to Fully Close Valve.Closing Spring Adjusted | |
| ML20086H085 | 31 October 1975 | AO 75-67:on 751021,torus Makeup Supply Isolation Check Valve 276Y Found Leaking in Excess of 2,000 Cc/Minute.Caused by Valve Piston Being Hung Up During Operation.Check Valve Repaired & Local Rate Test Repeated | |
| ML20086H056 | 31 October 1975 | Telecopy AO 75-71:on 751030,isolation Valve SV 3978B Failed. Cause Under Investigation.Corrective Action to Be Determined | |
| ML20086F938 | 31 October 1975 | AO 75-68:on 751021,O-ring Gasket Leak Discovered on Torus Purge Supply Valve AO-2521B.Caused by Use of Improper Connection for Testing Double O-ring Seal.Connection Capped & Leak Checked Successfully | |
| ML20086F929 | 31 October 1975 | AO 75-69:on 751021,nitrogen Found to Leak Out of Test Connection on Inboard Flange of AO-2519.Caused by Use of Wrong Connection for Testing Double O-ring Seal.Connection Capped & Leak Checked Successfully | |
| ML20086F952 | 30 October 1975 | AO 75-66:on 751020,APRM B Flow Bias Signal Failed Upscale. Caused by Internal Ground in Channel Flow Transmitter D Combined W/Installed Instrument Loop Ground,Lowering Total Loop Resistance.Defective Components Replaced | |
| ML20090D076 | 28 October 1975 | AO 75-29:on 751027,torus to Drywell Vacuum Breaker Alarm Sys II Failed to Annunciate When Vacuum Breaker V-26-8 Opened.Caused by Component Failure.Corrective Action Under Investigation | |
| ML20086H074 | 24 October 1975 | Telecopy AO 75-69:on 751023,O-ring Gasket Leak Found on Drywell Purge Supply Valve AO-3505.Cause Under Investigation.Corrective Action to Be Determined After Investigation | |
| ML20086H068 | 24 October 1975 | Telecopy AO 75-70:on 751024,drywell Purge Supply Isolation Valve AO-3520 Operated W/O Manual Initiation.Caused by Incorrect Implementation of Mod.Valve Failed Closed & Will Be Repaired | |
| ML20086F966 | 24 October 1975 | AO 75-65:on 751015,setpoints on Reactor High Pressure Scram Switches Found Less Conservative than Specified by Tech Specs.Caused by Instrument Setpoint Shift.Channel D Switch Recalibr,Tested & Returned to Svc | |
| ML20090D094 | 24 October 1975 | AO 75-28:on 751015,standby Gas Treatment Sys 1 Inoperable. Caused by Air Solenoid Valve Coil Failure.Defective Solenoid Coil Replaced | |
| ML20086H090 | 21 October 1975 | Telecopy AO 75-67:on 751021,torus Makeup Supply Isolation Check Valve 276Y Found Leaking in Excess of 2,000 Cc/Minute. Cause Under Investigation.Corrective Actions to Be Determined After Investigation | |
| ML20086H081 | 21 October 1975 | Telecopy AO 75-68:on 751021,torus Makeup Sys Isolation Valve AO-3523 Found to Leak in Excess of 2,000 Cc/Minute.Cause Under Investigation.Corrective Action to Be Determined After Investigation | |
| ML20086F958 | 21 October 1975 | Telecopy AO 75-66:on 751020,logic Aprm/Rbm B Flow Bias Signal from FT-2-2-110D Failed Upscale.Caused by Failure of Second Ground on Recirculation Drive Flow Transmitter Signal Loop.Flow Signal Corrected | |
| ML20086F944 | 21 October 1975 | Telecopy AO 75-68:on 751021,leak Found on O-ring Gasket on Torus Purge Supply Valve AO 2521A.Cause Under Investigation. Corrective Action to Be Determined After Investigation | |
| ML20086F949 | 21 October 1975 | Telecopy AO 75-67:on 751021,diesel Generator Breaker E-4 Inoperable.Caused by Inoperative Charging Motor Failing Due to Brush Wear.Breaker Replaced | |
| ML20086F933 | 21 October 1975 | Telecopy AO 75-69:on 751021,O-ring Gasket Leak Discovered on Drywell & Torus Inerting Nitrogen Supply Valve AO-2519.Cause Under Investigation.Corrective Action to Be Determined After Investigation | |
| ML20090D114 | 17 October 1975 | AO 75-27:on 751008,low Reactor Pressure Core Spray Valve Permissive Pressure Switches RE17B & D Tripped at Pressure Less than Min Required Value.Caused by Switch Repeatability. Pressure Switches Recalibr | |
| ML20090D104 | 16 October 1975 | AO 75-28:on 751015,standby Gas Treatment Sys 1 Inoperable. Caused by Air Solenoid Valve Coil Failure.Defective Solenoid Coil replaced.W/751016 | |
| ML20086F970 | 16 October 1975 | Telecopy AO 75-65:on 751015,setpoint on Reactor High Pressure Scram Switches Found to Be Less Conservative than Specified by Tech Specs.Caused by Instrument Setpoint Shift. Channel D Switch Recalibr,Tested & Returned to Svc | |
| ML20086H096 | 16 October 1975 | AO 75-66:on 751006,RCIC Inboard Steam Supply Isolation Valve MO-3-13-15 Failed to Close.Cause Not Identified.Valve Stroked Successfully.Failure Not Repeatable | |
| ML20086H106 | 10 October 1975 | AO 75-65:on 751002,drywell Radiation Monitor Inoperable. Caused by Rust Blockage of Pressure Control Valve.Valve Cleaned,Reassembled & Returned to Svc |