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Category:REPORTABLE OCCURRENCE REPORT (SEE ALSO AO
MONTHYEARML20012E0661990-03-0909 March 1990
RO 90-01:on 900228,reactor Operator Received Servo Fault Alarm.After Directed Shutdown,Complete Loss of Linear Power Channel Noted.Caused by Corroded Connector at Detector Leads.Connector Replaced.Part 21 Related
ML20028E6911983-01-11011 January 1983
Telecopy Ro:On 830110,during Reactor Startup,Fuel Temp Not Tracking Although Normal Temp Indication Displayed.Reactor Shut Down.Caused by Failed Fuel Thermocouple.Reactor Switched to Second Thermocouple
ML20028E6411983-01-0606 January 1983
Ro:On 830105,discovered Damaged Fuel Element 7463 During Insp.Element Failed Go/No Go Test.Complete Core Unloading & Fuel Insp Will Be Completed on 830106 & 07
ML20052B6671982-04-12012 April 1982
Ro:Final Rept Re Possible Loss of self-protection of SNM Ctr.Fuel Bundle May Not Have Decayed Below self-protection Limit as Discrepancies Existed in Readings.Survey Program Improved & Underwater Fuel Surveys Studied
ML20050B3531982-02-12012 February 1982
Ro:On 820205,during Initial Startup,Linear Power Channel Did Not Respond.Rod Withdrawal Terminated.Caused by Detector High Detector High Voltages Switch in Off Position.Training Session Implemented on Monitoring of Instrumentation
ML20009E4171981-05-15015 May 1981
Ro:On 810507,during Check of Reactor Operator Licenses & Status,Senior Operator License SOP-3478 Found Expired on 810427.Caused by Failure to Follow Administrative Procedures.Operator Relieved of Duties
ML19352B1651981-05-0808 May 1981
Ro:On 810507,while Conducting Check of Reactor Operator License & Requalification Status,Found That License SOP-3478 Held by Gw Waldrop Had Expired on 810427.Caused by Defect in Administrative Procedures.Procedures Have Been Corrected
ML19352B2101981-04-24024 April 1981
Ro:On 810409 & 14,during Reactor Prestartup Checks,Interlock Used to Prevent Withdrawal of Shim Safety Control Rods Found Not Functioning.Caused by Threshold Change Due to Change in Solid State Switching Device.Capacitor Installed
ML19318A5901980-05-23023 May 1980
Ro:On 800513,secondary Cooling Tower Fan Discovered to Have Disintegrated Causing Damage to Cooling Tower & Resulting in Loss of Secondary Cooling Capacity.Caused by Failure of Fan Transmission Mounting.Temporary Fan Assembly Installed
ML19323F1401980-05-13013 May 1980
Ro:On 800513,discovered Secondary Cooling Tower Fan Disintegrated Causing Damage to Tower & Loss of Secondary Cooling Capacity.No Cause Given.Reactor to Be Operated on Reduced Schedule Until Repairs Made
ML19224D7861979-06-25025 June 1979
Final RO Rept Re Failure of Experiment Scram Circuit to Function During Surveillance Testing Due to Malfunction of Reset Switch.Caused by Dust on Moving Parts.Switch Cleaned & Immediately Functioned
1990-03-09
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Category:LER)
MONTHYEARML20012E0661990-03-0909 March 1990
RO 90-01:on 900228,reactor Operator Received Servo Fault Alarm.After Directed Shutdown,Complete Loss of Linear Power Channel Noted.Caused by Corroded Connector at Detector Leads.Connector Replaced.Part 21 Related
ML20028E6911983-01-11011 January 1983
Telecopy Ro:On 830110,during Reactor Startup,Fuel Temp Not Tracking Although Normal Temp Indication Displayed.Reactor Shut Down.Caused by Failed Fuel Thermocouple.Reactor Switched to Second Thermocouple
ML20028E6411983-01-0606 January 1983
Ro:On 830105,discovered Damaged Fuel Element 7463 During Insp.Element Failed Go/No Go Test.Complete Core Unloading & Fuel Insp Will Be Completed on 830106 & 07
ML20052B6671982-04-12012 April 1982
Ro:Final Rept Re Possible Loss of self-protection of SNM Ctr.Fuel Bundle May Not Have Decayed Below self-protection Limit as Discrepancies Existed in Readings.Survey Program Improved & Underwater Fuel Surveys Studied
ML20050B3531982-02-12012 February 1982
Ro:On 820205,during Initial Startup,Linear Power Channel Did Not Respond.Rod Withdrawal Terminated.Caused by Detector High Detector High Voltages Switch in Off Position.Training Session Implemented on Monitoring of Instrumentation
ML20009E4171981-05-15015 May 1981
Ro:On 810507,during Check of Reactor Operator Licenses & Status,Senior Operator License SOP-3478 Found Expired on 810427.Caused by Failure to Follow Administrative Procedures.Operator Relieved of Duties
ML19352B1651981-05-0808 May 1981
Ro:On 810507,while Conducting Check of Reactor Operator License & Requalification Status,Found That License SOP-3478 Held by Gw Waldrop Had Expired on 810427.Caused by Defect in Administrative Procedures.Procedures Have Been Corrected
ML19352B2101981-04-24024 April 1981
Ro:On 810409 & 14,during Reactor Prestartup Checks,Interlock Used to Prevent Withdrawal of Shim Safety Control Rods Found Not Functioning.Caused by Threshold Change Due to Change in Solid State Switching Device.Capacitor Installed
ML19318A5901980-05-23023 May 1980
Ro:On 800513,secondary Cooling Tower Fan Discovered to Have Disintegrated Causing Damage to Cooling Tower & Resulting in Loss of Secondary Cooling Capacity.Caused by Failure of Fan Transmission Mounting.Temporary Fan Assembly Installed
ML19323F1401980-05-13013 May 1980
Ro:On 800513,discovered Secondary Cooling Tower Fan Disintegrated Causing Damage to Tower & Loss of Secondary Cooling Capacity.No Cause Given.Reactor to Be Operated on Reduced Schedule Until Repairs Made
ML19224D7861979-06-25025 June 1979
Final RO Rept Re Failure of Experiment Scram Circuit to Function During Surveillance Testing Due to Malfunction of Reset Switch.Caused by Dust on Moving Parts.Switch Cleaned & Immediately Functioned
1990-03-09
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Category:TEXT-SAFETY REPORT
MONTHYEARML20205Q3481998-12-31031 December 1998
Tx A&M Univ Sys Tx Engineering Experiment Station Nuclear Science Ctr 1998 Annual Rept. with
ML20151W2321998-09-0808 September 1998
Ro:On 980826,facility Bldg Air Monitor (Fam Channel 4) Failed Daily Fam Alarm Checks Prior to Reactor Operation. Caused by Failed Alarm Relay.Staff Is Preparing Formal Written Procedures for Testing Configurations for Fam Sys
ML20217A0891998-03-18018 March 1998
Ro:On 980218,potential Reactor Safety Failure Discovered W/ Reactor Shutdown.Caused by Manual Scram Function Bypassed by Sticking Reset Contact in Console Power key-switch. Protective Action Reset Switches Wired
ML20217K1401997-12-31031 December 1997
Tx A&M Univ Sys Tx Engineering Experiment Station Nuclear Science Ctr 1997 Annual Rept
ML20199C5371997-11-11011 November 1997
Ro:On 971030,shim Safety Number 2 Was Found to Be Binding & Became Stuck in Withdrawn Position & Control Rod Failed to Scram.Caused by Incorrect Spacing Between Hold Down Foot & Bundle top-handle.Procedure SOP-II-I Modified
ML20149F3901997-07-15015 July 1997
Safety Evaluation Supporting Amend 14 to License R-83
ML20137Y0351997-04-16016 April 1997
Rev 4 to Nuclear Science Center Senior Reactor Operator & Reactor Operator Requalification Program
ML20137H0541996-12-31031 December 1996
Tx A&M Univ Sys Tx Engineering Experiment Station Nuclear Science Center 1996 Annual Rept
ML20129H5191996-10-30030 October 1996
Ro:On 961015,loss of Facility Power Occurred Causing Reactor Scram Due to Lack of Attention to Detail & Excessive Distractions to Operations.Startup Checklist Had Several Individual Instrument Checks Combined Into Single Items
ML20115G5511995-08-31031 August 1995
Engineering Analysis of a Power Upgrade for Tx A&M Nuclear Science Ctr Reactor
ML20082D5521994-12-31031 December 1994
Thirty-First Annual Progress Rept of Tx A&M Univ Nuclear Science Ctr, for Period of 940101-1231
ML20069H4271993-12-31031 December 1993
Thirtieth Annual Progress Rept of Nuclear Science Ctr Tx Engineering Experiment Station Tx A&M Univ Sys College Station,Tx
ML20059G0301993-10-26026 October 1993
Safety Evaluation Supporting Amend 13 to License R-83
ML20094N5431991-12-31031 December 1991
Nuclear Science Center 28th Annual Rept,CY91
ML20079C2481991-06-10010 June 1991
Ro:On 910607,reactor Operated for 30 Minutes at 1 MW W/O Facility Air Monitors in Operation.Operator Removed from Watch Standing Duties.Final Rept Will Be Forwarded Upon Completion
ML20066H1401991-02-0808 February 1991
Special Rept 90-01:on 910125,during Annual Fuel Insp of Operational Core VIII-A,fuel Elements 6502 & 8468 Failed to Pass go-no-go Gauge Test for Excessive Transverse Bend. Elements Replaced W/Spare & Fuel Bundles Relocated
ML20070R9351990-12-31031 December 1990
Twenty-Seventh Progress Rept of Texas A&M Univ Nuclear Science Ctr Jan-Dec 1990
ML20070U0201990-12-31031 December 1990
Twenty-Sixth Progress Rept of Texas A&M Univ Nuclear Science Ctr,1990
ML20043F4391990-06-0404 June 1990
Revised Page 1 to Reactor Operator & Senior Reactor Operator Requalification Program,Rev Iii.Item 2.1.6 Changed to Include Physical Security Plan
ML20012E0661990-03-0909 March 1990
RO 90-01:on 900228,reactor Operator Received Servo Fault Alarm.After Directed Shutdown,Complete Loss of Linear Power Channel Noted.Caused by Corroded Connector at Detector Leads.Connector Replaced.Part 21 Related
ML20248J1691988-12-31031 December 1988
Twenty-Fifth Progress Rept of Texas A&M Univ Nuclear Science Ctr,Jan-Dec 1988
ML20151Y9031988-07-15015 July 1988
Review of Texas A&M Univ Nuclear Science Ctr - Beam Port Experiment
ML20151L6591988-03-23023 March 1988
Safety Evaluation Supporting Amend 11 to License R-83
ML20148M5691987-12-31031 December 1987
Twenty-Fourth Progress Rept of Texas A&M Univ Nuclear Science Ctr,1987
ML20205Q8241986-12-31031 December 1986
Twenty-Third Progress Rept of Texas A&M Univ,Nuclear Science Ctr for 1986
ML20203B0091986-07-10010 July 1986
Ro:On 860708,no Rod Down Indication Received for Transient Rod Until Carriage Driven In,During Performance of Manual Scram for Reactor Shutdown.Caused by Malfunction of Reactor Safety Sys Component.Repairs Underway
ML20199B1171986-06-0404 June 1986
Ro:On 860501,improper Handling of Experiment Discovered Which Could Have Resulted in Serious Operational Event. Caused by Insertion of $1.09 Reactivity.Postulated Accidents & Results & Related Info Encl
ML20205Q2921986-05-16016 May 1986
Final Ro:On 860501,unanticipated or Uncontrolled Change in Reactivity Greater than One Dollar Occurred.Caused by Removal of Rotisserie from Face Water Notch.Proposed Changes to SOPs Developed as Listed
ML20205J9311986-02-18018 February 1986
RO 86-01:on 860204,temp Recorder Providing LSSS Signal to Scram on High Fuel Temp Malfunctioned.Caused by Defective Motor Bearing.Bearing Replaced & Recorder Calibr
ML20199G0441985-12-31031 December 1985
Twenty-Second Progress Rept of Texas A&M Univ Nuclear Science Ctr,1985
ML20137Y6291985-09-24024 September 1985
RO-85-04:on 850912,transient Rod Followed Cylinder Out During Positioning of Transient Rod Cylinder.Air Solenoid for Transient Rod Sys Not Functioning as Designed.Air Solenoid Disassembled,Cleaned & Reassembled
ML20127M4151985-05-0909 May 1985
Ro:On 850508,during Restart Following Power Failure,Facility Air Monitoring (Fam) Sys Inoperable for 15 Minutes.Caused by Turning Off High Voltage to Detectors.Procedures Revised to Verify Fam Sys After Power Failure
ML20113D5681985-01-21021 January 1985
RO 85-2;on 850111,safety Channel 1 Detector Failed During Reactor Operation.Caused by Loose Connector Pin Making Intermittent Contact.New Connector Installed & Detector Verified Operable Prior to Reinstallation
ML20134Q1961985-01-11011 January 1985
Ro:On 850111,reactor Shut Down When Safety Channel 1 Did Not Respond Following Annual Reactor Maint.Cause Undetermined. Detector & Cabling Replaced
ML20134P7391985-01-10010 January 1985
RO 85-1:on 850108,fuel Temp Recorder Indicated 600 F Instead of 720 F.Caused by Failure of Reactor Safety Sys Channel. Faulty Slide Wire & Contact Arm Replaced
ML20134Q2081985-01-0808 January 1985
Ro:On 850108,fuel Temp Recorder Indicated 600 F Instead of 720 F After Reactor Power Returned to 1 MW Following Sample Positioning.Reactor Shut Down & Faulty Slide Wire & Contact Arm Replaced
ML20100C9651984-12-31031 December 1984
Twenty-First Progress Rept of Texas A&M Univ Nuclear Science Ctr,1984
ML20090E1251984-07-0202 July 1984
RO-84-4:on 840626,reactor Operator Noted That Fuel Element Temp Recorder Did Not Correspond to Digital Indication as Shown on Doric Temp Readout.Cause Not Stated.Failure Spurious & Could Not Be Reproduced
ML20090D7841984-06-26026 June 1984
Telecopy Ro:On 840626,fuel Elements Temp Recorder Failed to Respond Following Temporary Reduction in Reactor Power.Cause Not Stated
ML20090E1241984-06-15015 June 1984
RO 84-3:on 840604,reactor Operator Observed That Safety Power Measuring Channel 2 Not Responding as Reactor Power Level Increased Beyond 30 Kw.Caused by Loose Safety Channel 2 Signal Cable.Connector Replaced
ML20090E5141984-06-11011 June 1984
RO 84-2:on 840528,erratic Performance of Reactor Servo Control Not Noted in Log.Caused by Personnel Error.Operator Cautioned to Be More Observant While Taking Log Readings
ML20134Q2511984-06-0505 June 1984
Ro:On 840604,during Startup,Reactor Shut Down When Channel 2 Not Indicating in Expected Power Range.Caused by Faulty Connector.Faulty Signal Cable Connector Replaced & Normal Operations Resumed
ML20092N9211984-05-29029 May 1984
Ro:On 840528,operator Received Servo Fault Alarm & Linear Power Channel Indication Failed Low.Caused by High Voltage Supply for Linear Defector de-energized
ML20084H6171984-04-0202 April 1984
Ro:On 840319,discovered That Performance of Weekly Electronic Maint Checks Not Performed During Previous Wk of Operation.Caused by Inadequate Procedural Controls
ML20087N3381983-12-31031 December 1983
Twentieth Progress Rept of Texas A&M Univ,Nuclear Science Ctr,1983
ML20078P0111983-10-28028 October 1983
Ro:On 831004,high Power Scram Received During Initial Reactor Startup While Banking Shim Safety Control Rods After Reaching 1 MW Power.Caused by Operator Manipulation of Control Rods.Procedures & Proper Documentation Emphasized
ML20024E1251983-04-30030 April 1983
Nineteenth Progress Rept of Texas A&M Univ Nuclear Science Ctr for 1982. W/830516 Ltr
ML20071H9171983-04-30030 April 1983
Nineteenth Progress Rept of Tx A&M Univ Nuclear Science Ctr 1982
ML20076F0281983-04-30030 April 1983
Nineteenth Progress Rept of Texas A&M Univ Nuclear Ctr, 1982
ML20028E6911983-01-11011 January 1983
Telecopy Ro:On 830110,during Reactor Startup,Fuel Temp Not Tracking Although Normal Temp Indication Displayed.Reactor Shut Down.Caused by Failed Fuel Thermocouple.Reactor Switched to Second Thermocouple
1998-09-08
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TEXAS ENGINEERING EXPERIM ENT STATION THE TEXAS A&M UNIVERSITY SYSTEM
~~
COLLEGE STATION, TEXAS 77843 q# '[
E J L
24 April 1981 NUCLEAR SCIENCE CENTER 713/845-7551 0
Mr. G. L. Madsen d'
\f Office of Inspection and Enforcement . ( ,
Region IV U.S. Nuclear Regulatory Commission
' p Dgo -1 611 Ryan Plaza Drive, Suite 1000 g b' Arlington, Texas 76012 r 8 Rafcronca: Docket No. 50-128 N w Lo
.c3^
Subject:
Failure of Shim Safety Control Rod Source Count Interlock Reported 4-14-81
Dear Mr. Madsen:
Enclosed is a final report of a reportable occurrence observed during reactor pre-startup checks at the NSCR. This report is submitted in compliance with Section 6.4 and 1.8.c of change No. 11 of the Technical Specifications, Facility License No. -83 for the Nuclear Science Center, Texas A&M University.
S nSerely i -
J hn D. Randall irector JDR/ym cc: R. R. Berg, Chairman Reactor Safety Board Texas A&M University Enclosure
/ Moo?
5
//
1 RESEr*aCH AND DEVELOPMENT a:OR MANKIND
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,~.
Final Report of Failure of Shim Safety Control Rod Low Source Count Interlock Reps **aole Occurrence On April 9, 1981 and April 14, 1981 during reactor pre-startup checks of the NSCR it was determined that the interlock to prevent withdrawal of shim safety control rods for low source level was not functioning properly. In the mal-f unction on April 9,19ol the circuit provided a low level interlock alarm but failed to prevent the withdrawal of shim safety control rode 1 and 4.
Corrective maintenance was performed on the circuit and the pre-startup check performed. In the Lalfunction on April 14, 1981 the circuit again provided a low level interlock relay were not properly closing. After the relay was was replaced the circuit performed satisfactoruly and normal operations were resumed.
Af ter the April 14 malfunction, the circuit was again checked by an electronics technician. It was determined that the failure was intermittant which presented difficulties in diagnosis. After a comprehensive analysis it was determined that 22..VAC was superimposed on the +12 VDC control rod drive control sirnal.
This voltage did not originate in the power supply but was apparently picked up by inductance somewhere in the console. A proposal was presented te an NSC Staff Review that a lufD capacitor be installed between the positive and negative leads of the power supply for the control rod drive signal but would reduce the 22 VAC. Since all parts of the circuit apt aared to function normally it was deduced that the AC voltage had always been on the DC line.
However, a slight change in the solid state switching device or in other circuit components had apparently caused a threshold change that occassionally caused triggering by the AC, placing the circuit in the improper mode. Since the filtering action of the capacitor would reduce the AC component by a factor of twenty it was asserted that the problem would be alleviated. The circuit modification was approved by the NSC Staff Review.
Corrective Actign The ha fD capacitor was installed and the circuit tested. The AC voltage was reduced to approximately 1 VAC and the interlock and control rod drive circuits functioned normally. Due to the intermittant nature of the malfunction the fact that testing indicated proper operation was not deemed conclusive. The circuit was watched very carefully for the next several days. Since no failure has been observed for the last 128 days it is quite probable that the defect has been corrected.
+ - s 12 VDC I U)# COUNT RAEE - IM N ER -
SUPPLY -
-)
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INTERLOCK SHM SAFETY SETATE CONTROL SWITCH ROD DRIVE F1LTER CAPACITOR !!% STALLED TO REMOVE THE 22 VAC.
FIGURE I
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