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| Issue date | Title | Topic | |
|---|---|---|---|
| ML19210A151 | 12 February 1976 | Abnormal Occurrence 76-7/1P:on 760212,empty Snubber Fluid Reservoir Found at Location DHH-198.Leakage Due to Damaged Seal.Snubber Removed & Replaced | |
| ML19322A430 | 5 February 1976 | Abnormal Occurrence 76-6/1P on 760204:radiation Leak Detection Sys Out of Svc for 22-h.No Reactor Bldg Atmospheric Samples Taken.Caused by Cover Plate to Monitor Left Open Following Insp.Procedures Reviewed W/Personnel | |
| ML19210A158 | 26 December 1975 | Abnormal Occurrence 50-289/75-43:on 751218,one of Six Pressure Switches Tripped at Less Conservative Limits than Tech Specs During Channels Surveillance Test.Caused by Calibr Drift in Associated Pressure Switch PS-290 | |
| ML19210A145 | 19 December 1975 | Abnormal Occurrence 50-289/75-42:on 751210,outside Containment Isolation Valve for Steam Generator Sample Line CA-V5B Failed to Close.Caused by Valve Manual Operator Inadvertently Left Open by Reactor Personnel | |
| ML19210A173 | 25 November 1975 | Abnormal Occurrence 50-289/75-40:on 751112,stuck Contacts on Diesel Generator 1A Voltage Relays Threatened Function of Engineered Safety Feature.Caused by Pitting of Relay Contact.Relays Checked at Each Startup Pending Design Mods | |
| ML19261F148 | 24 November 1975 | Abnormal Occurrence 50-289/75-41:on 751114,personnel Failed to Strictly Follow Drain & Blanketing Procedure.Vented Center Control Rod Drive Mechanism Allowed Radioactive Gas Into Reactor Bldg.Personnel Counseled on Proper Procedures | |
| ML19210A183 | 21 November 1975 | Abnormal Occurrence 50-289/75-39:on 751112,control Rod 4 in Group 7 Dropped Into Core,Resulting in Asymmetrical Rod Signal & Automatic Power Reduction.Caused by Failure of Stator Winding.Stator Winding Replaced & Tested | |
| ML19210A189 | 31 October 1975 | Abnormal Occurrence 50-289/75-38:on 751021,control Rod Verification Program Not in Compliance W/Tech Specs.Caused by Procedure Misinterpretation.Revised Surveillance Program Will Clearly State Requirement of Individual Rod Movement | |
| ML19210A191 | 31 October 1975 | Abnormal Occurrence 50-289/75-37:on 751021,blocked Strainer on Outlet to Boric Acid Mixtank Decreased Flow Rate.Plant Shutdown Followed to Replace Strainer.Improper Design Allowing for One Strainer W/No Bypass Caused Blockage | Boric Acid |
| ML19210A202 | 29 October 1975 | Abnormal Occurrence 50-289/75-36:on 751019,auxiliary Operator Failed to Obtain Radiation Work Permit & Carry Monitoring Device.Caused by Improper Administrative Procedures | |
| ML19210A197 | 21 October 1975 | Abnormal Occurrence 75-37:on 751021,blocked Strainer on Outlet of Boric Acid Mixtank Decreased Flow Rate.Plant Shutdown Followed to Replace Strainer.Plant Returned to Svc in 15 Minutes | Boric Acid |
| ML19210A215 | 20 October 1975 | Abnormal Occurrence 50-289/75-35:on 751010,improper Mix of Boric Acid Crystals Caused Blockage in Mix Tank.Crystals Settling to Bottom of Tank Clogged Line to Reclaimed Boric Acid Storage Tank.Mixture Mod Should Correct Failures | Boric Acid |
| ML19210A221 | 10 October 1975 | Abnormal Occurrence 75-37:on 751010,during Transfer of Boric Acid from Storage Tank to Reclaim Tank,Blockage Noticed in Outlet Line.Caused by Boric Acid Crystals Settling to Drain Due to Improper Mixture | Boric Acid |
| ML19210A224 | 8 October 1975 | Abnormal Occurrence 50-289/75-34:on 750928,inoperative Hydraulic Shock Suppressor Threatened Function of Engineered Safety Feature.Low Fluid Level in Snubber Caused Failure. All Other Snubbers Checked Satisfactorily | |
| ML19322A437 | 30 September 1975 | Abnormal Occurrence 75-34 Re Disconnected Hydraulic Snubber within Reactor Bldg Secondary Shield.Investigation of Circumstances Incomplete.Snubber Replaced During Ongoing Seal Replacement Program | |
| ML19210A246 | 26 September 1975 | Abnormal Occurrence 50-289/75-31:on 750917,core Flood Tank Water Level Below Tech Specs Requirements.Caused by Incorrect Reading on Lower Reading Channel CF2-LT3.Channel Will Now Be Monitored & Personnel Informed on Procedures | |
| ML19210A241 | 26 September 1975 | Abnormal Occurrence 50-289/75-33:on 750917,de-ice Makeup Valve NR-V-4A Failed in Open Position.Failure Caused by High Resistance Contact in Closing Control Circuit Not Fully Energizing.All Control Contacts to Be Checked & Cleaned | |
| ML19210A239 | 26 September 1975 | Abnormal Occurrence 50-289/75-32:on 750918,incorrect Open Position of Air Supply Valves PP-V-47 & 179 Could Have Prevented Proper Functioning of Door Seals in Event of Emergency Safeguards Actuation.Jj Colitz 750919 Ltr Encl | |
| ML19210A245 | 19 September 1975 | Abnormal Occurrence 75-33 Re Failure of de-ice Makeup Valve NR-V-4A to Close Using Control Room Remote Pushbutton.Caused by High Resistance Contact in Closing Control Circuit. Contact Cleaned,Tested & Returned to Svc | |
| ML19322A436 | 18 September 1975 | Abnormal Occurrence 75-31 Re Low Borated Water Level in Core Flood Tank B.Caused by Improper Level Channel Transmitter LT3 Readout.Transmitter Adjusted | |
| ML19210A179 | 5 September 1975 | Abnormal Occurrence 50-289/75-29:on 750827,reactor Bldg Purge Supply Valve AH-V-1D Failed to Close Prior to Engineered Safeguards Test.Caused by Corroded Robotarm Actuator.Robotarm Actuator Lubricated | |
| ML19210A225 | 5 September 1975 | Abnormal Occurrence 50-289/75-30:on 750827,valve CF-V-2B of Core Flood Tank B Sample Line Isolation Failed to Close Upon Receipt of Engineered Safeguards Actuation Signal.Caused by Valve Binding Against Valve Stem | |
| ML19210A181 | 2 September 1975 | Abnormal Occurrence 50-289/75-28:on 750823,MS-V-13A Valve Turbine Drive Emergency Feed Pump Failed to Remain Open. Caused by Control Circuit Pressure Switch Failure,Due Possibly to High Ambient Temp | Time of Discovery |
| ML19210A187 | 29 August 1975 | Abnormal Occurrence 50-289/25-27:on 750821,crack & Leak Found in Auxiliary Makeup Pump a Suction Vent.Caused by Fatigue Due to Vibration.Cracks Repaired & Hydrostatically Tested.Failed Pipe Section Replaced | Hydrostatic |
| ML19322A435 | 28 August 1975 | Abnormal Occurrence 75-30:on 750827,core Flood Tank B Sample Line Isolation Valve CF-V2B Failed to Close Following Engineered Safeguards Signal.Valve Manually Closed Using Handwheel | |
| ML19210A186 | 27 August 1975 | Abnormal Occurrence 75-29:on 750827,reactor Bldg Supply Valve AH-V-1D Failed to Fully Close.Investigation Into Cause Underway | |
| ML19210A184 | 23 August 1975 | Abnormal Occurrence 75-28:on 750820,during Test of Turbine Drive Emergency Feed Pump,Associated Valve Failed to Remain Open.Caused by Failed Pressure Switch | |
| ML19210A190 | 21 August 1975 | Abnormal Occurrence 75-27 on 750821:leaks Found in Socket Weld Joint at Makeup Pump a & Suction Line Connection W/Pump Suction Header.Cause of Problem Under Investigation | |
| ML19210A194 | 1 August 1975 | Abnormal Occurrence 50-289/75-26:on 750724,high Reactor Coolant Pressure Trip Set Points Less Conservative than Tech Specs.Caused by Calibr Drift.Specs Will Be Changed to Account for Instrument Error | |
| ML19210A195 | 31 July 1975 | Abnormal Occurrence 50-289/75-25:on 750721,failure of Diesel Generator a Frequency Relay to Actuate,Threatening Nonperformance of Diesel Generator.Cause Presently Unknown | |
| ML19210A200 | 25 July 1975 | Abnormal Occurrence 50-289/75-23:on 750716,auxiliary Relay to Generator 1B Failed to Energize on Demand.Caused by Mfg Defect.Failed Relay Replaced & Remaining Relays Inspected | |
| ML19210A207 | 25 July 1975 | Abnormal Occurrence 50-289/75-24:on 750716,during Removal of River Water Pump NR-P1B from Svc,Discharge Valve Failed to Close.Caused by Open Phase on Winding Due to Severe Heat Resulting in Single Phasing of Other Windings | |
| ML19210A199 | 22 July 1975 | Abnormal Occurrence 75-25:on 750722,three Frequency Relays to Steam Generator a Found in Dropped Out State.Relays Replaced & Returned to Svc.Cause of Failure Yet to Be Determined | |
| ML19210A217 | 21 July 1975 | Abnormal Occurrence 50-289/75-22:on 750711,leaks Found in Socket Weld Joints of Makeup Pump Suction Vent Line MU-PIA Leading to Valve MU-V156A.Caused by Improper Spacing Between Moving Anchor & First Pipe Restraint | |
| ML19210A205 | 18 July 1975 | Abnormal Occurrence 75-23:on 750716,one of Three Auxiliary Relays of Diesel Generator 1B Breaker G11-02 Failed. Remaining Relays Tested Satisfactorily.Cause of Failure Under Investigation | |
| ML19210A212 | 18 July 1975 | Abnormal Occurrence 75-24:on 750716,river Water Pump Discharge Valve Failed Due to Low Valve Motor Winding Resistance & Winding Motor Overheating | |
| ML19210A222 | 11 July 1975 | Abnormal Occurrence 75-22:on 750711,leaks Found in Socket Weld Joints of Makeup Pump a Suction Line Vent.Caused by Pump Vibration | |
| ML19210A231 | 3 July 1975 | Abnormal Occurrence 50-289/75-21:on 750625,coolant Temp Trip Bistable Channel C Failed to Trip During Test of Reactor Protection Sys.Caused by Defective Printed Circuit Board Solder Joint in Signal Converter | |
| ML19210A237 | 27 June 1975 | Abnormal Occurrence 50-289/75-19:on 750618,variable Low Reactor Coolant Sys Pressure Trip Setpoints Less Conservative than Tech Specs.Caused by Channel C Trip Setpoint Out of Calibr Due to Instrument Drift | |
| ML19210A230 | 27 June 1975 | Abnormal Occurrence 75-03:on 750626,noble Gas Released to Auxiliary Bldg.Probable Cause:Evaporator Malfunction While Filling Makeup Tank or Coolant Bleed Tank.No Tech Specs Exceeded | |
| ML19210A162 | 27 June 1975 | Abnormal Occurrence 50-289/75-18:on 750615,QA Documentation from Vendor Found Inadequate for Repaired Decay Heat River Water Pump Motor Shaft.Caused by Lack of Administrative Controls | |
| ML19210A235 | 25 June 1975 | Abnormal Occurrence 75-21:on 750625,reactor Protection Sys Channel C Failed During Surveillance Test.Caused by Coolant Temp Trip Bistable Failure to Trip Due to Component Failure in Signal Converter | |
| ML19210A172 | 25 June 1975 | Abnormal Occurrence 50-289/75-17:on 750615,reactor Bldg Purge Isolation Valve Failed Local Leak Rate Test.Caused by Improper Valve Adjustment Procedures & Matl Defects Not Allowing Long Term Retention of Adjustment | |
| ML19308A537 | 23 June 1975 | Abnormal Occurrence 75-20:on 750622,while Returning to Full Power Operation After Forced Power Reduction,Reactor Power Increased Above Power Level Cutoff Before Xenon Reactivity Approached Stability.Procedures Under Review | |
| ML19210A243 | 19 June 1975 | Abnormal Occurrence 75-19:on 750618,less Conservative Variable Low Reactor Coolant Sys Pressure Trip Setpoint for One Channel of Reactor Protection Sys Violated Tech Specs. Caused by Instrument Drift for Channel C Setpoint Calibr | |
| ML19210A166 | 17 June 1975 | Abnormal Occurrence 75-18:on 750615,repaired Motor Shaft to Decay Heat River Water Pump Not Returned W/Proper QA Documentation.Caused by Lack of Administrative Control | |
| ML19210A175 | 17 June 1975 | Abnormal Occurrence 75-17:on 750615,during Test of Reactor Bldg Purge Isolation Valve Local Leak Rate Test,Two Exhaust Valves Would Not Pressurize to Required Test Pressure.Caused by Valve AH-V1A Failing to Fully Close | |
| ML19210A177 | 16 June 1975 | Abnormal Occurrence 50-289/75-16:on 750605,variable Low Reactor Coolant Sys Pressure Trip Setpoints Less Conservative than Tech Specs.Specific Cause Not Established. Setpoints Will Be Checked to Assure Proper Calibr | |
| ML19291B529 | 13 June 1975 | Abnormal Occurrence 50-289/75-15:on 750605,pressure Transmitter Trip Setpoint of Reactor Protection Sys Channel B Tested Out of Calibr.Caused by Trip Setpoint Calibr Drift | |
| ML19210A180 | 6 June 1975 | Abnormal Occurrence 75-16:improper Trip Setpoints on Variable Low Reactor Coolant Sys Pressure Sys Violated Tech Specs |