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| | number = ML20092G604 | | | number = ML20092G604 |
| | issue date = 09/14/1995 | | | issue date = 09/14/1995 |
| | title = Special Rept:On 950815,CNS Unit 1 DG 1A Invalid Failure Occurred Due to Main Bearing High Temp Trip Signal.Caused by Failed Splice Installed in Circuit for RTD 1LDRD5630.New RTD Installed in Main Bearing #5 | | | title = Special Rept:On 950815,CNS Unit 1 DG 1A Invalid Failure Occurred Due to Main Bearing High Temp Trip Signal.Caused by Failed Splice Installed in Circuit for RTD 1LDRD5630.New RTD Installed in Main Bearing 5 |
| | author name = Mccollum W | | | author name = Mccollum W |
| | author affiliation = DUKE POWER CO. | | | author affiliation = DUKE POWER CO. |
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Category:REPORTABLE OCCURRENCE REPORT (SEE ALSO AO LER)
MONTHYEARML20216E5401999-09-0707 September 1999 Special Rept:On 990826,discovered That Meteorological Sys Upper Wind Speed Cup Set Broken,Causing Upper Wind Channel to Be Inoperable.Cup Set Replaced & Channel Restored to Operable Status on 990826 ML20210R1051999-08-0606 August 1999 Special Rept:On 990628,cathodic Protection Sys Was Declared Inoperable After Sys Did Not Pass Acceptance Criteria of Bimonthly Surveillance.Work Request 98085802 Was Initiated & Connections on Well Anode Were Cleaned or Replaced ML20206P2081998-12-31031 December 1998 Special Rept:On 981218,inoperability of Meteorological Monitoring Instrumentation Channels,Was Observed.Caused by Data Logger Overloading Circuit.Replaced & Repaired Temp Signal Processor ML20198B1341998-12-14014 December 1998 Revised Special Rept:On 980505,discovered That Certain Fire Barriers Appeared to Be Degraded.Caused by Removal of Firestop Damming Boards.Hourly Fire Watches Established in Affected Areas ML20196D4041998-11-19019 November 1998 Rev 1 to Special Rept:On 980618,determined That Method Used to Calibrate Wind Speed Instrumentation Loops of Meteorological Monitoring Instrumentation Sys Does Not Meet TS Definition for Channel Calibration.Procedure Revised ML20153B0531998-09-16016 September 1998 Special Rept:On 980817,errors in Implementation of Selected Licensee Commitment Testing Requirements on Fire Protection Sys Instruments,Was Discovered.Caused by Error in Interpretation of SLC Requirement.Will Revise Procedures ML20236M9151998-07-0707 July 1998 Special Rept:On 980611,determined That Required Firewatch Patrol Had Been Missed.Caused by Firewatch Being Performed on Wrong Unit Due to Human Error.Employee Was Verbally Counseled on Firewatches & Documentation Was Corrected ML20236G4451998-07-0101 July 1998 Special Rept:On 980618,declared Wind Speed Instrumentation Loops of Meteorological Monitoring Instrumentation Sys Inoperable.Caused by Failure to Meet TS Definition of Channel Calibr.Will Revise Selected Licensee Commitment ML20248K1431998-06-0202 June 1998 Special Rept:On 980505,discovered That Certain Fire Barriers Appeared to Be Degraded.Caused by Shrinkage of Foam & Improper Installation During Construction of Plant.Posted Fire Watches & Repaired Firestop F-AX-348-W-134 ML20247H5351998-04-12012 April 1998 Special Rept:On 980415,missed Insp of Fire Hose Caskets Was Discovered.Caused by Error in Transferring Info from One Procedure to Another.Planned Rev of Applicable Procedure to Include Gasket Insp at Appropriate Frequency ML20216B0211998-04-0606 April 1998 Special Rept:On 980325,determined That Loose Parts Monitoring Sys Being Inoperable for Greater than Thirty Days.Caused by Incorrect Testing.All Channels of Loose Parts Monitoring Sys Tested Utilizing Revised Test Method ML20217K9271998-03-26026 March 1998 Special Rept:On 971229,procedure Step for Closing Safety Injection Pump Cold Leg Injection Isolation Valve Was Inadvertently Skipped.Caused by Injection of Water Into RCS from Rwst.Simplified Procedures & Discussed Event ML20216D5641998-03-0505 March 1998 Special Rept:On 980204,discovered That Fire Detection Panel Was Apparently Not Communicating W/Several Local Fire Detectors.Caused by Faulty Computer Sys Cards.Replaced Four Computer Cards in Sys ML20202C4701998-02-0505 February 1998 Ro:On 971228:Unit 1 Loose Parts Monitoring Sys Channel 6 Was Declared Inoperable Due to Excessive Static on Channel. Caused by Loose Connection.Work Order Has Been Written to Pursue Repairs ML20138E6851997-04-24024 April 1997 Special Rept:On 970318,Unit 1 Loose Parts Monitoring Sys Channel 13 Was Declared Inoperable Due to Sporadic Electical Static.Channel Was Removed from Svc & Entered Into TS Action Item Logbook as Inoperable ML20149M7251997-01-20020 January 1997 Special Rept:On 961209,Unit 1 Loose Parts Monitoring (Lpm) Sys Channel 20 Declared Inoperable Due to No Signal Being Received from Field.Lpm Channel 20 & 22 Operable & Providing Monitoring Coverage for Primary Side of 1D S/G ML20134K4901996-11-0606 November 1996 Special Rept:On 961009,selective Licensee Commitment for Operability of Fire Protection Sprinkler Sys Not Maintained. Continuous Fire Watch Established within One H Following Identification of Incorrect Remedial Action ML20134H1331996-11-0404 November 1996 Special Rept:On 961004,Unit 1B DG Failed Due to Failure of Motor Operated Pot,Electronic & Mechanical Governor,Governor Droop Relay & Mechanical Binding of Fuel Rack Control Linkage.Dg Procedures Will Be Revised ML20113A1801996-06-17017 June 1996 Special Rept:On 960521,declared Detectors A01 for Zone 69 & A04 for Zone 60 Inoperable Because Detectors Effectively Isolated from Area in Intended Protection.Detectors Relocated,Tested & Declared Operable on 960524 ML20100H9801996-02-20020 February 1996 Special Rept:On 960111,Unit 1 Loose Parts Monitoring Channel 21 Declared Inoperable,Due to Spurious,Unexplainable Electronic Bursts.Work Request Initiated to Pursue Corrective Action ML20100H9751996-02-20020 February 1996 Special Rept:On 960111,Unit 2 Loose Parts Monitoring Sys Channel 7 Declared Inoperable,Due to pre-amp Bias Voltage Indicating Zero Volts Twice During Previous Seven Days.Work Request Written to Pursue Corrective Action ML20097F5011996-02-11011 February 1996 Special Rept:On 960102,Unit 2 Loose Parts Monitoring Sys Channel 17 Was Declared Inoperable.Two Other Channels Operable & Providing Coverage Against Loose Parts ML20096E7731996-01-12012 January 1996 Special Rept:On 951214,unit 2 DG Valid Failure Occurred. Caused by Fuel Line Fitting Backing Off from Cylinder Head Connection,Which Resulted in Fuel Oil Leakage.Dg Successfully Started,Run & Declared Operable on 951215 ML20096A8761995-12-18018 December 1995 Special Rept:On 951120,during Periodic Surveillance Testing, Lpms Channel 5 Declared Inoperable.Caused by Erratic Preamp Bias Voltage Indications.Work Request 95048483 Initiated to Perform Corrective Maint During Unit 1 Cycle 9 ML20094Q5811995-11-13013 November 1995 Special Rept:On 951014,auxiliary Bldg Filtered Exhaust Sys Pump Room Heater Declared Inoperable Due to Blown Fuse & Not Restored to Operable Status within 7 Days Per Ts. Technical Investigation Will Be Performed ML20094B8291995-10-25025 October 1995 Special Rept:On 950919,loose Parts Monitoring Sys Channel 1 Declared Inoperable Due to Erratic Preamp Bias Indication. Work Request Written to Investigate & Repair Channel ML20098A4641995-09-19019 September 1995 Special Rept:On 950817,Unit 2 Lpms Channel 12 Was Declared Inoperable Due to Channel Sensor Failing Acceptance Criteria During Performance of PT/O/A4600/03 ML20092G6041995-09-14014 September 1995 Special Rept:On 950815,CNS Unit 1 DG 1A Invalid Failure Occurred Due to Main Bearing High Temp Trip Signal.Caused by Failed Splice Installed in Circuit for RTD 1LDRD5630.New RTD Installed in Main Bearing 5 ML20086H1401995-07-12012 July 1995 Special Rept:On 950615,Channel 4 Was Declared Inoperable Due to Noise Uncharacteristic of Healthy Channel Detected Via Vibration & Loose Parts Monitoring Sys.Corrective Maint Will Be Performed During 1EOC9 Outage ML20086H1431995-07-11011 July 1995 Special Rept:On 950608,Channel 13 Was Declared Inoperable. Trending of Bias Voltage & Background Rms Evaluated to Conclude Channel Was Experiencing Periodic Failures. Corrective Maint Will Be Performed During 1EOC9 Outage ML20086C6441995-06-29029 June 1995 Special Rept:On 950523,Unit 1 Train a Fuel Handling Ventilation Filter Heaters Declared Inoperable.Evaluation Done to Determine Fault ML20085M4061995-06-20020 June 1995 Special Rept:On 950501,lower Rv Tube 4 Was Declared Inoperable ML20084N7271995-05-25025 May 1995 Special Rept:On 950425,valid Failure of DG 1A Occurred. Caused by Jacket Water Thermostatic Control Valve Sticking in Position Which Reduced Engine Cw Flow Through Heat Exchanger.Thermostatic Cv Internals Removed & Replaced ML20082L2711995-04-17017 April 1995 Special Rept:On 950308,Unit 2 Cathodic Protection Sys Was Declared Inoperable & Remained Inoperable Greater than 10 Days ML20081D4851995-03-13013 March 1995 Special Rept:On 950211,actuation of PORV 1NC32B Occurred. Procedure OP/1(2)/A/6100/02 Revised to Require More Emphasis on Monitoring Pressure Indication During Sensitive Evolutions ML20080Q8701995-03-0202 March 1995 Special Rept:On 950202,Unit 1 DG 1B Invalid Failure Due to Overcurrent Breaker Trip During Governor Troubleshooting ML20149H7821994-12-20020 December 1994 Special Rept:On 941129,discovered That Selective Licensee Commitment (SLC) for Visual Insp of Fire Rated Assemblies Exceeded Due to Misinterpretation of Requirements of SLC 16.9-5.Fire Barriers Visually Inspected ML20078R0021994-12-12012 December 1994 Special Rept:On 941103,Channel 3 (Upper Rv a) Declared Inoperable.Caused by Channel Sensor Failure of Acceptance Criteria During Performance of PT/0/A/4600/03.Repair Planned for End of 2EOC7 Outage Due to Containment Entry Required ML20078K7361994-11-17017 November 1994 Special Rept on 941021,DG 1A Invalid Failure Occurred Due to Main Bearing High Temp Trip.Operability Performance Test Successfully Completed & Engine Declared Operable on 941022 ML20149G8041994-11-0101 November 1994 Special Rept:On 940922,CNS,Unit 2 Cathodic Protection Sys Declared Inoperable & Remained Inoperable for Greater than 10 Days.Wo 94080948-01 Initiated to Replace Prepackaged Anode Well 1.WO Scheduled for 941114 ML20076F3191994-10-0404 October 1994 Special Rept:On 940908,valid Failure of D/G 1A Occurred Due to Air Start Valve Sticking Open.Maint Procedure MP/0/A/7650/99 Revised,New Air Roll Criteria Developed & Sixteen Starting Air Valves Replaced ML20072P4251994-08-23023 August 1994 Ro:On 940719,channel 9 (S/G a Channel 2) Declared Inoperable.Work Request Was Generated to Repair Channel During Future Outage of Sufficient Length Since Containment Entry Required for Work ML20072E5961994-08-15015 August 1994 Special Rept:On 940715,inoperability of Unit 2 Vibration & Loose Parts Monitoring System Channel 4 & 6 Occurred.Caused by Leds Not Lighting During Performance of PT/0/B/4600/03. Work Orders 94051250-01 & 94051251-01 Initiated ML20071N7441994-07-28028 July 1994 Special Rept:On 940711,delta-t Channel on Chart Recorder Found to Be out-of-tolerance Due to Drifting of Analog to Digital (A/D) Converter Card.A/D Card Replaced & delta-t Channel Chart Recorder Declared Operable ML20071N8511994-07-28028 July 1994 Special Rept:On 940711,main Steam Relief Valve Exhaust Monitors Declared Inoperable Due to Engineering Calculation Concerns.Engineering Calculation CNC-1229.00-00-0047 re-performed Using EPA-400 Methodology ML20070K0191994-07-18018 July 1994 Special Rept:On 940630,re Inoperability of Main Steam Line Radiation Monitor 2EMF12.Work Request 94026262 Generated to Reattach 2EMF12 to Main Steamline.Work Request Completed on 940701 ML20069H0861994-05-31031 May 1994 Special Rept:On 940501,Unit 2 DG 2A Invalid Failure Occurred Due to Right Bank Turbocharger Vibration Trip.Based on Cooper-Enterprise Recommendations,Procedure Changes Made to Calibr Procedures for All Four DGs ML20065K5011994-04-13013 April 1994 Special Rept:On 940314,invalid Failure of Diesel Generator 1B Occurred Due to Output Tripping During Calibration of Electronic Governor.Dg 1B Started Successfully on 940315 & Declared Operable ML20064G2911994-03-15015 March 1994 Special Rept:On 940203,SG Channels 9 & 11 Declared Inoperable.Channels Failed to Meet Band Limited Rms Acceptance Criteria During Performance of 18 Month Channel Calibr Test.Work Request Written to Repair Channels ML20064G2771994-03-0707 March 1994 Special Rept:On 940125,Channels 6,7 & 10 Were Declared Inoperable.Channels Failed to Meet Acceptance Criteria During Performance of 18 Month Channel Calibr Test.Work Request Written to Repair Channels 1999-09-07
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217H0201999-09-30030 September 1999 Monthly Operating Repts for Sept 1999 for Catawba Nuclear Station,Units 1 & 2 ML20216E5401999-09-0707 September 1999 Special Rept:On 990826,discovered That Meteorological Sys Upper Wind Speed Cup Set Broken,Causing Upper Wind Channel to Be Inoperable.Cup Set Replaced & Channel Restored to Operable Status on 990826 ML20212B4711999-08-31031 August 1999 Monthly Operating Repts for Aug 1999 for Catawba Nuclear Station,Units 1 & 2 ML20217H0321999-08-31031 August 1999 Revised Monthly Operating Rept for Aug 1999 for Catawba Nuclear Station,Units 1 & 2 ML20211B1281999-08-31031 August 1999 Dynamic Rod Worth Measurement Using Casmo/Simulate ML20211A9791999-08-20020 August 1999 Safety Evaluation Granting Licensee Request for Approval of Proposed Relief from Volumetric Exam Requirements of ASME B&PV Code,Section Xi,For Plant,Unit 2 ML20211F3441999-08-17017 August 1999 Updated non-proprietary Page 2-4 of TR DPC-NE-2009 ML20211C1291999-08-17017 August 1999 ISI Rept Unit 1 Catawba 1999 RFO 11 ML20210R1051999-08-0606 August 1999 Special Rept:On 990628,cathodic Protection Sys Was Declared Inoperable After Sys Did Not Pass Acceptance Criteria of Bimonthly Surveillance.Work Request 98085802 Was Initiated & Connections on Well Anode Were Cleaned or Replaced ML20210S2891999-07-31031 July 1999 Monthly Operating Repts for July 1999 for Catawba Nuclear Station,Units 1 & 2 ML20212B4871999-07-31031 July 1999 Revised Monthly Operating Rept for July 1999 for Catawba 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 ML20210S2951999-06-30030 June 1999 Revised Monthly Operating Rept for June 1999 for Catawba Nuclear Station,Units 1 & 2 ML20209H4501999-06-30030 June 1999 Monthly Operating Repts for June 1999 for Catawba Nuclear Station,Units 1 & 2 ML20209H4561999-05-31031 May 1999 Revised Monthly Operating Rept for May 1999 for Catawba 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 ML20196A0001999-05-31031 May 1999 Monthly Operating Repts for May 1999 for Catawba Nuclear Station,Units 1 & 2 ML20206P5201999-05-14014 May 1999 Safety Evaluation Accepting GL 96-05, Periodic Verification of Design-Basis Capability of Safety-Related Motor-Operated Valves ML20206N8391999-05-0404 May 1999 Rev 16 to CNEI-0400-24, Catawba Unit 1 Cycle 12 Colr ML20206R1811999-04-30030 April 1999 Monthly Operating Repts for Apr 1999 for Catawba Nuclear Station,Units 1 & 2 ML20196A0041999-04-30030 April 1999 Revised Monthly Operating Repts for Apr 1999 for Catawba Nuclear Station,Units 1 & 2 ML20206N8261999-04-22022 April 1999 Rev 15 to CNEI-0400-24, Catawba Unit 1 Cycle 12 Colr. Page 145 of 270 of Incoming Submittal Not Included ML20205S5551999-04-21021 April 1999 Safety Evaluation Accepting Response to GL 96-06, Assurance of Equipment Operability & Containment Integrity During Design Basis Accident Conditions ML20205N3651999-04-12012 April 1999 Safety Evaluation Accepting IPE of External Events Submittal ML18016A9011999-04-12012 April 1999 Part 21 Rept Re Defect in Component of DSRV-16-4,Enterprise DG Sys.Caused by Potential Problem with Connecting Rod Assemblies Built Since 1986,that Have Been Converted to Use Prestressed Fasteners.Affected Rods Should Be Inspected ML20206R1931999-03-31031 March 1999 Revised Monthly Operating Repts for Apr 1999 for Catawba Nuclear Station,Units 1 & 2 ML20205P9521999-03-31031 March 1999 Monthly Operating Repts for Mar 1999 for Catawba Nuclear Station,Units 1 & 2 ML20205P9561999-02-28028 February 1999 Revised Monthly Operating Repts for Feb 1999 for Catawba Nuclear Station,Units 1 & 2 ML20204C9111999-02-28028 February 1999 Monthly Operating Repts for Feb 1999 for Catawba Nuclear Station,Units 1 & 2 ML20203A2581999-02-0505 February 1999 Safety Evaluation of TR DPC-NE-3002-A,Rev 2, UFSAR Chapter 15 Sys Transient Analysis Methodology. Rept Acceptable. Staff Requests Duke Energy Corp to Publish Accepted Version of TR within 3 Months of Receipt of SE ML20204C9161999-01-31031 January 1999 Revised Monthly Operating Repts for Jan 1999 for Catawba Nuclear Station,Units 1 & 2 ML20199K8711999-01-13013 January 1999 Inservice Insp Rept for Unit 2 Catawba 1998 Refueling Outage 9 ML20199E3071998-12-31031 December 1998 Monthly Operating Repts for Dec 1998 for Catawba Nuclear Station,Units 1 & 2 ML20216F9931998-12-31031 December 1998 Piedmont Municipal Power Agency 1998 Annual Rept ML20205E9441998-12-31031 December 1998 1998 10CFR50.59 Rept for Catawba Nuclear Station,Units 1 & 2, Containing Brief Description of Changes,Tests & Experiments,Including Summary of Ses.With ML20206P2081998-12-31031 December 1998 Special Rept:On 981218,inoperability of Meteorological Monitoring Instrumentation Channels,Was Observed.Caused by Data Logger Overloading Circuit.Replaced & Repaired Temp Signal Processor ML20203A4101998-12-22022 December 1998 Rev 16 to CNEI-0400-25, Catawba Unit 2 Cycle 10 Colr ML20203A4041998-12-22022 December 1998 Rev 14 to CNEI-0400-24, Catawba Unit 1 Cycle 11 Colr ML20198B1341998-12-14014 December 1998 Revised Special Rept:On 980505,discovered That Certain Fire Barriers Appeared to Be Degraded.Caused by Removal of Firestop Damming Boards.Hourly Fire Watches Established in Affected Areas ML20196J8351998-12-0808 December 1998 Safety Evaluation Granting Relief Request Re Relief Valves in Diesel Generator Fuel Oil Sys ML20199E3221998-11-30030 November 1998 Revised MOR for Nov 1998 for Catawba Nuclear Station,Units 1 & 2 Re Personnel Exposure ML20198E3151998-11-30030 November 1998 Monthly Operating Repts for Nov 1998 for Catawba Nuclear Station,Units 1 & 2 ML20196C0251998-11-27027 November 1998 SER Accepting Clarification on Calibration Tolerances on Trip Setpoints for Catawba Nuclear Station ML20196A6881998-11-25025 November 1998 Safety Evaluation Granting Relief Request 98-02 Re Limited Exam for Three Welds ML20196D4041998-11-19019 November 1998 Rev 1 to Special Rept:On 980618,determined That Method Used to Calibrate Wind Speed Instrumentation Loops of Meteorological Monitoring Instrumentation Sys Does Not Meet TS Definition for Channel Calibration.Procedure Revised ML20195E5521998-10-31031 October 1998 Monthly Operating Repts for Oct 1998 for Catawba Nuclear Station,Units 1 & 2 ML20198E3261998-10-31031 October 1998 Revised Monthly Operating Repts for Oct 1998 for Catawba Nuclear Station,Units 1 & 2 ML20154M7661998-10-12012 October 1998 LER 98-S01-00:on 980913,terminated Vendor Employee Entered Protected Area.Caused by Computer Interface Malfunction. Security Retained Vendor Employee Badge to Prevent Further Access & Computer Malfunction Was Repaired.With 1999-09-07
[Table view] |
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, Meh>ua Company H?wwR McCmint, JR Catauha Nuclear G wation &partment Vice hesider:t 48M Concor11Rwu (SW)s3/m Onice Yrsk, SCTJin (SW)3314C6 Fat DUKEPOWER September 14,;1995 U. S. Nuclear Regulatory t ommission ATTN: Document Control Desk l
Washington, DC 20555 .
l l
- 1. 1 i
Subject:
Catawba Nuclear Station, Unit 1 Docket No. 50-413 Special Report Invalid Failure of Diesel Generator 1A 1
I Pursuant to Technical Specification 4.8.1.1.3 and G.9.2, find attached a Special Report concerning the Unit 1 Diesel Generator (DG 1A) invalid failure which occurred on August 15, 1995.
1 Sincerely, W. R. McCollum l KEN \ DG1 A0914.95 i
Attachment xc: S. D. - Ebneter, Regional Administrator l
> R. E. Martin, ONRR
'/
(
R. J. Freudenberger, SRI
~ 9509190378 950914-PDR ADOCK 05000413 a.;8
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, SPECIAL REPoPT CATAWBA NUCLEAR STATION DOCKET No. 50-413 j DIESEL GENERATOR 1A INVALID FAILURE DUE To MAIN BEARING HIGH TEMPERATURE TRIP SIGNAL An invalid failure of Diesel Generator (DG 1A) occurred on 08/15/95 due j to a main bearing high temperature trip signal. It was determined that a )
failed splice installed in the circuit for Resistance Temperature Detector l (RTD) 1LDRD5630 was the cause of the trip signal. Unit 1 was in Mode 1 (Power Operations) at 100% power when this failure occurred. There has been 1 valid failure in the last 20 valid tests and 3 valid failures in the last 100 valid tests on DG 1A. DG 1A was on a monthly test frequency at the time of this failure. The DG 1A was unavailable for 6.23 hours2.662037e-4 days <br />0.00639 hours <br />3.80291e-5 weeks <br />8.7515e-6 months <br /> due to this invalid failure.
On 08/15/95, DG 1A was being prepared for the monthly operability test.
Following the air roll, the display for Main Bearing #5 RTD (1LDRD5630) was indicating ~ 300 F on the Rosemount Alarm Monitor. The other bearing indications were reading in their normal range (140 - 150 F).
Work Order #95064091-01 was initiated to investigate and repair this problem.
During the process of performing initial checks, the temperature dropped to its normal reading. Instrument and Electrical (IAE) personnel checked all connections external to the engine for the RTD. The terminations in the junction box en the side of the engine were tightened slightly. The l I
indication displayed a normal reading. Operations (OPS) proceeded with the DG 1 A run. Approximately 20 minutes into the full load run, the l annunciator for High Bearing Temperature trip was received and the )
engine automatically shutdown. The operators immediately went to the l Rosemount Alarm Monitor and observed that the alarm light for 1LDRD5630 l had actuated, however temperature for this point was agreeing with the other bearing RTDs. At this point, all work was halted on DG 1A and the Failure Investigation Process (FIP) was started.
The FIP team identified several possible equipment failure modes that would have led to the initiation of the High Bearing Temperature Trip.
Each of these failure modes were tested. Using this process, it was discovered that a failed splice in the wiring for ILDRD5630 was the root cause of the inadvertent trip.
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i SPECIAL REPORT CATAWBA NUCLEAR STATION DOCKET NO. 50-413 DIESEL GENERATOR 1A INVALID FAILURE DUE TO MAIN BEARING HIGH TEMPERATURE TRIP SIGNAL This same RTD had been replaced on 10/21/94, which is documented in Problem Investigation Process -(PIP) #1-C94-1495 due to it failing high during an engine run. At that time, a splice was made inside the DG to connect the replacement RTD. One of the possible equipment failure modes identified by the FIP team on 08/15/95 was the bad splice from the previous inst 911ation. When the engine was entered to investigate the status of this splice, it was observed by the IAE crew that the condition of the Raychem heat shrink tubing, which had been used to insulate and protect the splice from the harsh lube oil environment, had changed from-the earlier installation. The Raychem that covered the three butt splices had softened and expanded on the RTD wire. By gently touching this splice, the point for 1LDRD5630 on the Alarm Monitor would immediately increase and go into an alarm condition. This was indicative of an open circuit occurring in the RTD wiring at the point of the spilce. IAE clipped the RTD wire and removed the RTD and its associated splice from the engine. The Raychem heat shrink area was then cut open to examine the internal butt splices. The individual splices were covered with electrical tape. .The tape was removed and it was seen that the butt splice for the white wire had a broken wire on one side. It is not known
.whether most of the wire strands broke during initial installation, or whether engine vibration combined with the looseness of the heat shrink caused the wire strands to break at the point of the splice.
A new RTD was installed in Main Bearing #5. The cable was run through the conduit on the side of the engine and terminated in junction box 1TBOX0597. No splice was made inside the engine. The operability performance test was successfully completed on 08/16/95 (start #1076) and the DG 1A engine was declared operable.
The trip for high temperature on the main bearings is not an emergency trip function and would have been bypassed had an emergency start signal been received. The failure of this splice would not have affected the DG's ability to start and accept loads had it been needed for a design basis event. Therefore, this event is classified as an invalid failure.
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g- -.
, SPECIAL REPORT CATAMBA NUCLEAR STATION l DOCKET NO. 50-413 DIESEL GENERATOR 1A INVALID FAILURE DUE TO MAIN BEARING HIGH TEMPERATURE TRIP SIGNAL 1
PIP 1-C95-1250 has been generated to address the incompatibility of the Raychem heat shrink with the lube oil environment and any other generic concerns involving splicing. Upon discovering the degraded splice in DG 1A, research was performed to determine if this same situation existed
- in any othec DGs. It was determined that DG 2A and 2B each had one splice that utilized Raychem Heat Shrink inside the engine. DG 2A had a splice installed for 2LDRD5620 on 03/4/93 during the initial installation of the modification that replaced the pneumatic non-emergency trip system with an electronic system (NSM CN-20528) per VN CC-3682. A note was added at that time to CN-2777-01.15 that specified using Raychem Heat Shrink to cover the butt splices. DG 2B had a splice that involved the use of Raychem installed per Work Order #94081546-01 1 ? 2LDRD5720 on 11/15/94 due to a previous erratic indication problem. There have been no problems seen with ' the indications for these two RTDs since the installation of these splices. Work Orders #95064971-01 and #95065069-01 were initiated and have been completed for DG 2A and DG 2B, respectively, to remove the RTDs with splices and replace them with ones where no splice is used in the installation. PIP 2-C95-1253 was initiated to address the note on CN-2777-01.15 that specifies using Raychem.
Corrective Action (CA) #1 in that PIP has been assigned to ESE to delete that note from the drawing. The editorial minor mod to remove this note is scheduled to be completed by 02/16/96.
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