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Category:ABNORMAL OCCURRENCE REPORTS (SEE ALSO LER & RO)
MONTHYEARML20084N6461977-03-31031 March 1977 Followup AO 50-249/75-44A:on 751125,offgas Activity Increased.Ge Insp Revealed Major Defect in Fuel Assembly DD-418.Assembly Removed from Reactor ML20084E3631976-06-29029 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 ML20084N6831976-06-29029 June 1976 Supplemental AO 50-249/1975-42A:motor Operated Valve 3-1501-5D Failed to Open During Testing Due to Thermal Overload Trip.Caused by Undersized Overload Heaters.Overload Heater Will Be Replaced W/Larger Capacity Unit ML20084D1191976-04-13013 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 ML20084D1541976-01-14014 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 ML20090E4581975-12-17017 December 1975 Supplemental AO 50-237/75-44:diesel Generator Failed to Start.Caused by Air Relay Valve Failure Due to Sticking O-rings.O-rings Replaced ML20084N6541975-12-11011 December 1975 AO 50-249/75-44:on 751125,offgas Increase Exhibited Which May Have Represented Abnormal Degradation of Fuel Cladding.Cause Unknown.Investigation Underway ML20090E4321975-11-20020 November 1975 AO 50-237/75-52:on 751116,MSIV AO 2-203-1C Closing Time Found Below Tech Spec Section 3.7.D.1.Caused by Out of Adjustment Hydraulic Bleedoff Valve.Bleedoff Valve Readjusted ML20090E4751975-11-0606 November 1975 AO 50-237/75-51:on 751031,torus Water Level Exceeded Tech Spec Limit During HPCI Sys Surveillance.Caused by Operator Failure to Verify Proper Valve Lineup.Water Pumped from Torus Until Level Dropped Below Tech Spec Limits ML20084N6881975-10-20020 October 1975 AO 50-249/75-42:on 750920,motor Operated LPCI Suction Valve 3-1501-5D Failed to Open Twice During Testing. Apparently Caused by Defective Valve Motor.Valve Motor Will Be Replaced ML20090E4781975-10-17017 October 1975 AO 50-237/75-49:on 751009,LPCI Loop Selection Logic Circuitry Failed to Select Preferred B Loop.Caused by Out of Calibr Differential Switch 261-34 & Electrically Shorted Switch 261-34D.Mod to Provide Signal Dampening Initiated ML20090E4471975-10-17017 October 1975 AO 50-237/75-48:on 751007,through-wall Crack Discovered in Drywell/Torus Nitrogen Purge Line 1604-18.Caused by Rapid & Uneven Contraction of Line Tee Connection Due to Liquid Nitrogen Impingement Resulting from Boiler Failure ML20084N8331975-10-15015 October 1975 Supplemental AO 50-249/75-22:plant Mod Being Initiated to Eliminate Valve Seat Failures Due to Cryogenic Stress ML20090E4811975-10-0909 October 1975 AO 50-237/75-45:on 750929,HPCI Turbine Failed to Trip at Designated Reactor Coolant Level.Caused by Open Circuit in Turbine Trip Solenoid Valve Coil Due to Failure of Cold Solder Joint within Coil.Hpci Trip Solenoid Valve Replaced ML20090E4821975-10-0909 October 1975 AO 50-237/75-46:on 750929,reactor Scrammed on High Drywell Pressure During Drywell Inerting Process.Caused by Operator Valving Error,Allowing Nitrogen Flow to Bypass Inerting Pressure Control Valve Into Drywell.Operators Cautioned ML20084N6711975-10-0707 October 1975 AO 50-249/75-43:on 750927,leak Discovered in Drain Line from Feedwater Heater 3D3 to Heater 3C3.Caused by Poor Weld Installation of Drain Line Pipe Support.Crack Ground Out & Pipe Rewelded ML20090E4641975-10-0202 October 1975 AO 50-237/75-44:on 750923,diesel Generator Failed to Start.Caused by Operator Failure to Follow Monthly Insp Procedure & QC Procedure for safety-related Component Replacement.Air Start Sys Inspected & Seal Ring Replaced ML20090E4701975-09-19019 September 1975 AO 50-237/75-43:on 750911,diesel Generator Cooling Water Pump Main Breaker Tripped.Caused by Excessive Heat Buildup within Breaker Housing.Breakers on Buses Replaced & Cover Plates Removed for Ventilation ML20084N6911975-09-16016 September 1975 AO 50-249/75-41:on 750908,intermediate Range Monitors 11, 12,14,16 & 18 Failed to Respond During Plant Startup. Apparently Caused by Personnel Accidentally Loosening Cables.Cables Replaced ML20090E4911975-09-0808 September 1975 AO 50-237/75-42:on 750829,diesel Generator Cooling Water Pump Tripped,Followed by Diesel Generator Trip on High Temp. Cause Not Established.Investigation of Cooling Water Pump & Associated Breakers Continuing ML20084N7771975-09-0404 September 1975 AO 50-249/75-38:on 750826,pressure Switches 3-263-52A1 & 52A2 Found W/Setpoints Above Tech Spec Limit.Apparently Caused by Setpoint Drift Due to Long Periods of Inactivity. Switches Reset ML20084N8411975-09-0404 September 1975 AO 50-249/75-37:on 750826,pressure Switches PS3-263-53A,53B & 53C Had Setpoints Above Tech Spec Limit.Apparently Caused by Setpoint Drift Due to Long Periods at Zero Pressure. Setpoints Reset ML20084N7281975-09-0404 September 1975 AO 50-249/75-40:on 750827,during Routine Instrument Surveillance,Pressure Switches PS3-263-51A & 51B Had Setpoints Above Tech Spec Limit.Caused by Drifting Due to Long Periods at Zero Pressure.Switches Reset ML20084N7481975-09-0303 September 1975 AO 50-249/75-39:on 750826,overload Relay Tripped Twice on Motor Operated Isolation Valve 3-220-1.Caused by Defective Overload Relay.Relay Replaced ML20084N7941975-09-0202 September 1975 AO 50-249/75-36:on 750823,reactor High Pressure Sensors 263-55A,55B & 55C Found W/Setpoints Above Tech Spec Limit. Apparently Caused by Extended Periods at Zero Pressure. Switches Reset ML20084N8661975-08-29029 August 1975 AO 50-249/75-35:on 750821,circuit Breaker 152-3403 Failed to Trip During Breaker Trip Test.Caused by Failure of Trip Coil.Breaker Replaced ML20084N8821975-08-15015 August 1975 AO 50-249/75-34:on 750807,isolation Condenser High Flow Switches 1349A & B Exhibited Instrument Setpoint Drift.Cause Unknown.Switches Reset ML20084N9051975-07-31031 July 1975 AO 50-249/75-32:on 750721,clamp Bolt Keeper Tack Welds on Jet Pumps 6 & 17 Failed.Caused by Poor Tack Welding.Clamp Bolt Keepers Rewelded & Successfully Retested ML20084E0461975-07-0303 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 ML20084D2111975-07-0303 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 ML20084N9141975-07-0303 July 1975 AO 50-249/1975-31:on 750626,cracks Discovered on Collet Housings of Control Rod Drives 984,883,1032 & 1099. Apparently Caused by Temp Cycles Drive Experiences During Reactor Scram.Analyses Initiated ML20084D1771975-06-25025 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 ML20084D0381975-06-23023 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 ML20084N7741975-06-20020 June 1975 Followup to AO Rept Re Correlation of Fuel Failures, Identified by Wet Sipping Tests to Calcualted Violations of GE Pciomr ML20084D0531975-06-20020 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 ML20084D1411975-06-18018 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 ML20084N9751975-06-13013 June 1975 AO 50-249/1975-30:on 750605,standby Liquid Control Pump Discharge Relief Valves Found at Setpoints Lower than Tech Spec Limits.Caused by Setpoint Drift.Valves Cleaned & Reset ML20084D1911975-06-13013 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 ML20084D2161975-06-0505 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 ML20084D2211975-06-0505 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 ML20084D2251975-06-0303 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 ML20084D4121975-05-30030 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 ML20084D4271975-05-30030 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 ML20084D4321975-05-29029 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 ML20084D8811975-05-27027 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 ML20084D3781975-05-23023 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 ML20084D4411975-05-23023 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 ML20084D8831975-05-23023 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 ML20084D8881975-05-21021 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 ML20084E0431975-05-21021 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 1977-03-31
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20249C8491999-09-30030 September 1999 1999 Third Quarter Rept of Completed Changes,Tests & Experiments Evaluated,Per 10CFR50.59(b)(2), for Dresden Nuclear Power Station. with ML20217A1691999-09-22022 September 1999 Part 21 Rept Re Engine Sys,Inc Controllers,Manufactured Between Dec 1997 & May 1999,that May Have Questionable Soldering Workmanship.Caused by Inadequate Personnel Training.Sent Rept to All Nuclear Customers ML20210R6081999-07-31031 July 1999 Monthly Operating Repts for July 1999 for Dresden Nuclear Power,Units 1,2 & 3.With ML20209E1291999-06-30030 June 1999 Monthly Operating Repts for June 1999 for Dresden Nuclear Power Station,Units 1,2 & 3.With ML20209J3481999-06-30030 June 1999 1999 Second Quarter Rept of Completed Changes,Tests & Experiments, Per 10CFR50.59.With ML20210D3071999-06-30030 June 1999 Corrected Page 8 to MOR for June 1999 for DNPS Unit 3 ML20195G6381999-05-31031 May 1999 Monthly Operating Repts for May 1999 for Dresden Nuclear Power Station,Units 1,2 & 3.With ML20195B2591999-05-19019 May 1999 Rev 66a to CE-1-A,consisting of Proposed Changes to QAP for Dnps,Qcs,Znps,Lcs,Byron & Braidwood Stations ML20206N2821999-04-30030 April 1999 Monthly Operating Repts for Apr 1999 for Dresden Nuclear Power Station,Units 1,2 & 3.With ML20206B1901999-03-31031 March 1999 First Quarter Rept of Completed Changes,Tests & Experiments Per 10CFR50.59 for Dresden Nuclear Power Station. with ML20205N7491999-03-31031 March 1999 Monthly Operating Repts for Mar 1999 for Dresden Nuclear Power Station,Units 1,2 & 3.With ML20207M6921999-02-28028 February 1999 Monthly Operating Repts for Feb 1999 for Dresden Nuclear Power Station,Units 1,2 & 3.With ML20207E9311999-02-26026 February 1999 Part 21 Rept Re Sprague Model TE1302 Aluminum Electrolytic Capacitors with Date Code of 9322H.Caused by Aluminum Electrolytic Capacitors.Affected Capacitors Replaced ML20199M0891999-01-22022 January 1999 Part 21 Rept Re Failure of Square Root Converters.Caused by Failed Aluminum Electrolytic Capacitory Spargue Electric Co (Model Number TE1302 with Mfg Date Code 9322H).Sent Square Root Converters Back to Mfg,Barker Microfarads,Inc ML20199D3261998-12-31031 December 1998 10CFR50.59 SER for 1998-04 Quarter, of Changes,Tests & Experiments.With ML20199C8951998-12-31031 December 1998 Monthly Operating Repts for Dec 1998 for Dnps,Units 1,2 & 3 ML20205M7061998-12-31031 December 1998 Unicom Corp 1998 Summary Annual Rept. with ML20197G8591998-11-30030 November 1998 Monthly Operating Repts for Nov 1998 for Dresden Nuclear Power Station.With ML20196A4191998-11-19019 November 1998 Safety Evaluation Accepting QA TR CE-1-A,Rev 66 Re Changes in Independent & Onsite Review Organization by Creating NSRB ML20196J0061998-11-19019 November 1998 Rev 66 to Topical Rept CE-1-A, QA Program ML20195D2861998-10-31031 October 1998 Monthly Operating Repts for Oct 1998 for Dresden Nuclear Power Station.With ML20154L3681998-09-30030 September 1998 Monthly Operating Repts for Sept 1998 for Dresden Nuclear Power Station,Units 1,2 & 3.With ML20154N4131998-09-30030 September 1998 1998 Third Quarter 10CFR50.59 Rept, for Dresden Nuclear Power Station of Completed Changes,Tests & Experiments ML20153C5061998-09-21021 September 1998 SER Accepting Qualified Unit 1 Supervisor Initial & Continuing Training Program for Dresden Nuclear Power Station,Unit 1 ML20151Y2711998-08-31031 August 1998 Monthly Operating Repts for Aug 1998 for Dresden Nuclear Power Station,Units 1,2 & 3.With ML20237E2331998-08-21021 August 1998 Revised Pages of Section 20 of Rev 66 to CE-1-A, QA Topical Rept ML20237A7161998-07-31031 July 1998 Monthly Operating Repts for July 1998 for Dresden Nuclear Power Station,Units 1,2 & 3 ML20236Q5851998-06-30030 June 1998 1998 Second Quarter 10CFR50.59 Rept, for Dresden Nuclear Power Station of Completed Changes,Tests & Experiments ML20236F8131998-06-30030 June 1998 Rev 0 to Defueled SAR Dresden Nuclear Power Station Unit 1 Commonwealth Edison Co ML20236T8331998-06-30030 June 1998 COLR for Dresden Station Unit 3,Cycle 15 ML20236T8391998-06-30030 June 1998 Rev 1 to EMF-96-141, Dresden Unit 3 Cycle 15 Reload Analysis Rept ML20236M6041998-06-30030 June 1998 Monthly Operating Repts for June 1998 for Dresden Nuclear Power Station,Units 1,2 & 3 ML20248M3021998-05-31031 May 1998 Monthly Operating Repts for May 1998 for Dresden Nuclear Power Station,Units 1,2 & 3 ML20248F3531998-05-21021 May 1998 Part 21 Rept Re Electronic Equipment Repaired or Reworked by Integrated Resources,Inc from Approx 930101-980501.Caused by 1 Capacitor in Each Unit Being Installed W/Reverse Polarity. Policy of Second Checking All Capacitors Is Being Adopted ML20247F3391998-04-30030 April 1998 Monthly Operating Repts for Apr 1998 for Dresden Nuclear Power Station,Units 1,2 & 3 ML20217D0281998-04-22022 April 1998 Part 21 Rept Re Additive Constants Used in MCPR Determination for Siemens ATRIUM-9B Fuel by Core Monitoring Sys Were Found to Be non-conservative.SPC Personnel Notified All Customers w/ATRIUM-9B Lead Test Assemblies ML20216D4411998-03-31031 March 1998 First Quarter Rept of Completed Changes,Tests & Experiments for 10CFR5059 ML20216C9651998-03-31031 March 1998 Monthly Operating Repts for Mar 1998 for Dresden Nuclear Power Station,Units 1,2 & 3 ML20216E2531998-02-28028 February 1998 Monthly Operating Repts for Feb 1998 for Dresden Nuclear Power Station ML20202F7831998-01-31031 January 1998 Monthly Operating Repts for Jan 1998 for Dresden Nuclear Power Station ML20199K1651998-01-23023 January 1998 Rev 65h to Topical Rept CE-1-A, Comm Ed QA Tr ML20198P5321997-12-31031 December 1997 Monthly Operating Repts for Dec 1997 for Dresden Nuclear Power Station ML20198P7021997-12-31031 December 1997 Fourth Quarter Rept of Completed Changes,Tests & Experiments Per 10CFR50.59 ML20216D3611997-12-31031 December 1997 Unicom Corp 1997 Summary Annual Rept ML20203F8781997-11-30030 November 1997 Monthly Operating Repts for Nov 1997 for Dresden Nuclear Power Station ML20199B0701997-10-31031 October 1997 Monthly Operating Repts for Oct 1997 for Dresden Nuclear Power Station ML20217H7201997-09-30030 September 1997 Monthly Operating Repts for Sept 1997 for Dresden Nuclear Power Station,Units 1,2 & 3 ML20210V2401997-09-19019 September 1997 Rev 65g to Topical Rept CE-1-A, Comm Ed QA Manual ML20216J3781997-08-31031 August 1997 Monthly Operating Repts for Aug 1997 for DNPS ML20210H5511997-07-31031 July 1997 Monthly Operating Repts for July 1997 for DNPS IAW RG 1.16 & GL 97-02 1999-09-30
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q CImmh:lth Edison One First t....cnal Plata. Chicago. Ilhnois b
1 Address Reply to: Post Office Box 767 Chicago, Illinois 60690 ;
Dresden I!uclear Power Station R. R. #1 Morris, Illinois 60450
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Mr. J. F. O'Loary, Director 6 JUN111974 x $
Directorate of Licensing u. m: w:r ,Q 4W1 /
U. S. Atemic Energy Comission SN:
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Washington, D.C. 20545 ,q
SUBJECT:
LICE'!SE DPR-19 DRESDEI! I'UCLEAR PC'e'ER STATICU Ut'IT 2.
SUPPLWEI;TARY II?C7.!'ATICi! TO REPCRT 07 AR'ICR:'AL CCCURREIICE PER SECTIC" 6.6.B.2 CP TH;' TECH!!ICAL SPECIFICATIC::S.
_UTTIT 2 DIESEL GE::E3ATOR TRIP
Reference:
Report of Abnormal Occurrence to 15. J. F. O' Leary of the Atomic Energy Comission dated March 8,1974.
Dear Mr. O' Leary:
This letter is to furnish supplementary informatien to our report of March 8,1974, concerning Unit 2 Diesel Generator Trip. In that report we :tated that the fuse clic holders wouhi ha mMiNM neh that they would be permanently installed in the circuit.
On further inspection it was discovered that the failure as reported was due to a desien failure. The original design of the fuse clip door was such that when closed it allowed improper alignment of the fuse clips. The improper aliennent was due to the fact that when the door was closed it was secured in only one corner. Being secured in only one corner allowed the door to bow slightly causing misaligned fuse clips.
To correct the bow a modification to the fuse clip holder door was performed. The modification did not permanently install the fuses in the circuit as reported. Instead it added three tuist locks to the door such that when closed it would be secured evenly. As of this date the twist lecks have been installed on the unit 2, 3 and 2/3 diesel generators.
Sincerely, f/ /
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II.'B. S,tephenson Superintendent BBS:TEL:ju b L l cc: TEL v' U,g 62.13 AEC Corr. Cat. I 1jf 4)
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,ional Plaza Chicago, Illmois O Adaress Reply to: Post Othee Box 767 Chicago, Illinois 60690 WPW Ltr.#175-74 Dresden Nuclear Power Station R. R. #1 Morris, Illinois 'v W March 8, 1974 p Mh ,'; g b-4
.s Mr. J. F. O' Leary, Director Directorate of Licensing
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U. S. Atomic Energy Commission L .a m Washington, D. C. 20545 % m sas -
SUBJECT:
- LICENSE DPR-19, DRESDEN NUCLEAR POWER STATION ' REPORT OF ABNORMAL OCCURRENCE PER SECTION 6.6.B.2 0F THE TECHNICAL SPECIFICATIONS.
UNIT 2 DIESEL GENERATOR TRIP.
References:
- 1) Notification of Region III of AEC Regulatory Operations.
Telephone: Mr. F. Maura, 1420 hours on March 4, 1974.
- 2) Dresden Station Electrical Prints 12E2334, 12E2336, and 12E2346
Dear,
Mr. g' Leary- , ,, ,
This letter is to report a condition relating to the operation of the unit at 1905 hours on March 1, 1974. At this time, the unit diesel tripped due to a differential fault. This malfunction is contrary to the basis for section 3.9 of the Technical Specifications which requires that an adequate supply of electrical power be available during operation.
EROBLEM Following the replacement of the Unit 2 diesel generator fuel oil hose, the diesel was started and ran for an operational test. During this test, the diesel generator tripped af ter about 40 minutes of operation.
At the time of the occurrence, the unit was just critical, thermal power was about 3 megawatts with the mode switch in the startup positien.
INVESTIGATION An investigation into the problem revealed that a differential I trip occurred due to an intermittent open on the "B" phase of the diesel generator output. The open on "B" phase was due to a failure of the bus fuse clips which were found burnt off.
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' On further investigation, it was discovered that the clips had been replaced during the last unit outage because the original clips
' appeared burnt. The replacement clips appeared to be manufactured in a different manner than the original clips since they were slightly longer
- and did not have the elasticity that the original clips had. . .
_ CORRECTIVE ACTION Since both the original and the replacement clips appeared to experience the identical problem, it was decided to modify the fuse compartment. The modification will permanently install the fuse holders in the circuit and eliminate the fuse clips. At this time a work request has been kritten which requests a modification to all three station diesels.
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EVALUATION During the occurrence of this failure, the safety of the plant and public was not in jeopardy. The loss of the unit diesel occurred when thermal power was only about three megawatts. Also at the time of
- the failure, the 2/3 diesel was operable and all incoming lines were l available.
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fl SU3 JECT DPR-19 DRESDEN NUCLE AR POWER ST ATION UNIT I 2. THIS WILL CONFIRM A CONFIRMATION WITH MR. F. MAURA 0F b YO'JR OFFICE AT 1420 HOURS THIS DATE CONCERNING A TRIP 0F l THE UNIT 2 STAND BY DIESEL GENERATOR DUING AN b OPER A3ILITY TEST FOLLOWING MAINTENANCE. THE DIESEL O
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HAD OPERATED FOR APPRO XIMATELY 40 MINUTES PRIOR TO T!!E TRIP, b WHICH WAS CAUSED BY DIFFERENCIAL FAULT. IT WAS DETERMINED THAT ll O
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#41ss 4% 799 ROOSEVELT ROAD ygtzpunug GLEN ELLYN. ILLINOIS 60137 (312)85s.2660 A. RO Inspection Report No.
Transmittal Date :
Distribution: Distribution:
RO Chief, FS&EB RO Chief, FS&EB RO:HQ (5) RO:HQ (4)
DR Central Files L:D/D for Fuels & Materials Regulatory Standards (3) DR Central Files Licensing (13) RO Files R0 Files B. RO Inquiry Report No.
Transmittal Date :
Distribution: Distribution:
R0 Chief, FS&EB RO Chief, FS&EB RO:HQ (5) RO:HQ DR Central Files DR Central Files Regulatory Standards (3) RO Files Licensing (13)
RO Files C. Incident Notification From: Commonwealth Edison Co. Docket No. 50-237 (Licensee & Docket No. (or License No.) ,
Transmittal Date : March 13, 1974 Distribution: Distribution:
R0 Chief, FS&EB RO Chief, FS&EB RO:HQ (4) RO:HQ (4)
Licensing (4) L:D/D for Fuels & Materials f DR Central Files DR Central Files RO Files RO Files i
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