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Category:REPORTABLE OCCURRENCE REPORT (SEE ALSO AO LER)
MONTHYEARML20210P3051999-08-0505 August 1999
Ro:On 990708,credible Single Failure in SR Temp Sys Could Result in Loss of Capability of Temp Sys to Protect Limiting Safety Sys Settings.Single Failure Is Loss of 15 V DC Power Supply.Mod Request 134 to Temp Sys Was Submitted
ML20209E9771999-07-0808 July 1999
Preliminary Rept of non-routine Occurence Re Identification of Possible Single Failure for Safety Related Temperature Sys on 990706.Low Temperature Auto Rundown Proposed & Problem Rept Initiated to Document Review of Event
ML20196B2091998-11-25025 November 1998
RO Update:On 981028,reactor Was Shutdown Upon Discovery That RB Ventilation Dampers Would Not Automatically Close.Damper Cylinder Was Repaired on 981102 & Reactor Operation Resumed on 981103
ML20154J6761998-10-0909 October 1998
RO 20:on 980925,Reactor Operators Made Error at Ford Nuclear Reactor in Implementing Calorimetry Procedures to Raise Power Level.Upon Discovery of Error Made in Linear Level Setpoint Reactor Power Was Reduced by 1% to Compensate
ML20153H0841998-09-28028 September 1998
Special Rept:On 980925,inadequate Procedure Implementation Resulted in Possible steady-state Reactor Operation at 2.02 MW Thermal Power.Interim Reactor Manager Reviewed Calorimeter Data & Did Not See Any Obvious Errors
ML20151Z1571998-09-17017 September 1998
Revised Ro:On 980817,980811 Event Re Slow Inward Drift of CR Reoccurred.Caused by Worn Worm Gear & Missing Full Turn of Worm Thread.Installed & Tested Drive Gear Coupling. Previously Submitted Ltr Rept Dtd 980911,deleted Text
ML20151W6391998-09-11011 September 1998
Special Rept:On 980811,swing Shift Operators Noted That CR Would Slowly Drift Inwards When in Manual Control with CR low-raise Switch in Neutral.Cr lower-raise Switch Was Removed,Inspected & Cleaned,Then Reinstalled & Tested
ML20236W0781998-07-30030 July 1998
RO 19:on 980720,determined That Reactor Was Operating W/ Inoperable Alarm Circuit on Bridge Radiation Monitor.Caused by Spurious Alarms Due to Temp & Humidity Sensitivity. Maint Procedures CP-216 & CP-219 Were Modified
ML20236T0741998-07-23023 July 1998
Non-routine Rept:On 971112,reactor Operators Shut Down Ford Nuclear Reactor to Remove Piece of Polyethylene Irradiation Container.Caused by Lack of Oversight.Method Will Be Adopted to Track Quartz & Polyethylene Samples
ML20236S2921998-07-20020 July 1998
RO-19:on 980720,reactor Operation w/in-operable Alarm Circuit on Bridge Radiation Monitor,Was Disabled.Caused by Spurious Alarms Due to Temperature & Humidity Sensitivity. Reactor Shutdown Pending Further Investigation
ML20248L5931998-06-0303 June 1998
Ro:On 980510,discovered 75 Gallon Loss of Pool Water to Radioactive Liquid Retention Tank Sys.Caused by Leak in One of Two Resin Columns Comprising B Hot Demineralizer (Hot Di) Sys.Modified Operating Procedure OP-211 Encl
ML20057F4521993-10-0606 October 1993
Follow-up on RO 18,dtd 930805 Re Release of low-level Radioactive Water from RB to Drain Tiles Around Foundation of Bldg.Line from Foundation Tiles Drains to Reactor Cold Sump,Through Which Water Released Permanently Sealed
ML20128D4641992-11-25025 November 1992
Ro:On 921124,control Rod Interlock Sys Removed from Reactor Control Sys.Caused by Wiring Error Made During Mod That Disabled Interlock That Drops Reactor Out of Automatic Control.Control Rod Withdrawn to 23 Inches
ML20058N7841990-08-0606 August 1990
RO 13:on 900721,tritium Content in Heavy Water Tank in Excess of 50 Ci.Samples Sent to Kms Fusion.Health Physics Procedure 107 Corrected to Reflect Correct Density of Heavy Water
ML20246F3881989-05-0303 May 1989
RO 12:on 881227,concentrations of I-131 & Xe-133 Discovered in Reactor Pool Water.Caused by B&W Element 204 Releasing Fission Products.B&W Contacted to Review Mfg Process.Air Samples Will Be Taken Above Pool on Monthly Basis
1999-08-05
[Table view]
Category:TEXT-SAFETY REPORT
MONTHYEARML20210P3051999-08-0505 August 1999
Ro:On 990708,credible Single Failure in SR Temp Sys Could Result in Loss of Capability of Temp Sys to Protect Limiting Safety Sys Settings.Single Failure Is Loss of 15 V DC Power Supply.Mod Request 134 to Temp Sys Was Submitted
ML20209E9771999-07-0808 July 1999
Preliminary Rept of non-routine Occurence Re Identification of Possible Single Failure for Safety Related Temperature Sys on 990706.Low Temperature Auto Rundown Proposed & Problem Rept Initiated to Document Review of Event
ML20205B0631998-12-31031 December 1998
Rept of Reactor Operations for Jan-Dec 1998 for Ford Nuclear Reactor Michigan Memorial - Phoenix Project Univ of Michigan,Ann Arbor. with
ML20206P3021998-12-31031 December 1998
Revised Rept of Reactor Operations for Jan-Dec 1998 for Ford Nuclear Reactor Michigan Memorial - Phoenix Project Univ of Mi,Ann Arbor
ML20196B2091998-11-25025 November 1998
RO Update:On 981028,reactor Was Shutdown Upon Discovery That RB Ventilation Dampers Would Not Automatically Close.Damper Cylinder Was Repaired on 981102 & Reactor Operation Resumed on 981103
ML20155J1131998-10-29029 October 1998
Part 21 Rept Re Failure of EDs to Automatically Close.Cause Due to Discovery That Air Cylinder That Operates RB Ventilation Supply & EDs Was Hanging Up.Reactor Will Remain Shut Down Until Damper Cylinder Is Repaired
ML20154J6761998-10-0909 October 1998
RO 20:on 980925,Reactor Operators Made Error at Ford Nuclear Reactor in Implementing Calorimetry Procedures to Raise Power Level.Upon Discovery of Error Made in Linear Level Setpoint Reactor Power Was Reduced by 1% to Compensate
ML20153H0841998-09-28028 September 1998
Special Rept:On 980925,inadequate Procedure Implementation Resulted in Possible steady-state Reactor Operation at 2.02 MW Thermal Power.Interim Reactor Manager Reviewed Calorimeter Data & Did Not See Any Obvious Errors
ML20151Z2701998-09-17017 September 1998
Safety Evaluation Supporting Amend 45 to License R-28
ML20151Z1571998-09-17017 September 1998
Revised Ro:On 980817,980811 Event Re Slow Inward Drift of CR Reoccurred.Caused by Worn Worm Gear & Missing Full Turn of Worm Thread.Installed & Tested Drive Gear Coupling. Previously Submitted Ltr Rept Dtd 980911,deleted Text
ML20151W6391998-09-11011 September 1998
Special Rept:On 980811,swing Shift Operators Noted That CR Would Slowly Drift Inwards When in Manual Control with CR low-raise Switch in Neutral.Cr lower-raise Switch Was Removed,Inspected & Cleaned,Then Reinstalled & Tested
ML20236W0781998-07-30030 July 1998
RO 19:on 980720,determined That Reactor Was Operating W/ Inoperable Alarm Circuit on Bridge Radiation Monitor.Caused by Spurious Alarms Due to Temp & Humidity Sensitivity. Maint Procedures CP-216 & CP-219 Were Modified
ML20236T0741998-07-23023 July 1998
Non-routine Rept:On 971112,reactor Operators Shut Down Ford Nuclear Reactor to Remove Piece of Polyethylene Irradiation Container.Caused by Lack of Oversight.Method Will Be Adopted to Track Quartz & Polyethylene Samples
ML20236T0801998-07-23023 July 1998
Development of Model Characterizing Heat Transfer in MTR Fueled Ford Nuclear Reactor
ML20236S2921998-07-20020 July 1998
RO-19:on 980720,reactor Operation w/in-operable Alarm Circuit on Bridge Radiation Monitor,Was Disabled.Caused by Spurious Alarms Due to Temperature & Humidity Sensitivity. Reactor Shutdown Pending Further Investigation
ML20248L5931998-06-0303 June 1998
Ro:On 980510,discovered 75 Gallon Loss of Pool Water to Radioactive Liquid Retention Tank Sys.Caused by Leak in One of Two Resin Columns Comprising B Hot Demineralizer (Hot Di) Sys.Modified Operating Procedure OP-211 Encl
ML20217K8811998-04-23023 April 1998
Corrected First Page of Safety Evaluation Supporting Amend 44 to License R-28,changing Date in First Paragraph to 970930 & Date in Second Paragraph to Oct 1996
ML20216J3501998-04-16016 April 1998
Safety Evaluation Supporting Amend 44 to License R-28
ML20217H1891997-12-31031 December 1997
Rept of Reactor Operations Jan-Dec 1997 for Ford Michigan Memorial - Phoenix Project Univ of Mi Ann Arbor
ML20137F2251996-12-31031 December 1996
Rept of Reactor Operation Jan-Dec 1996 for Ford Nuclear Reactor Mi Memorial - Phoenix Project Univ of Mi Ann Arbor
ML20137K7671996-12-31031 December 1996
Annual Rept of Reactor Operations for Period 960101-1231
ML20057F4521993-10-0606 October 1993
Follow-up on RO 18,dtd 930805 Re Release of low-level Radioactive Water from RB to Drain Tiles Around Foundation of Bldg.Line from Foundation Tiles Drains to Reactor Cold Sump,Through Which Water Released Permanently Sealed
ML20059M3161993-08-0101 August 1993
Rev 2 to Safety Analysis
ML20128D4641992-11-25025 November 1992
Ro:On 921124,control Rod Interlock Sys Removed from Reactor Control Sys.Caused by Wiring Error Made During Mod That Disabled Interlock That Drops Reactor Out of Automatic Control.Control Rod Withdrawn to 23 Inches
ML20058N7841990-08-0606 August 1990
RO 13:on 900721,tritium Content in Heavy Water Tank in Excess of 50 Ci.Samples Sent to Kms Fusion.Health Physics Procedure 107 Corrected to Reflect Correct Density of Heavy Water
ML20055H1141990-07-18018 July 1990
Requalification Program Ford Nuclear Reactor
ML20245F9791989-08-0404 August 1989
Safety Evaluation Supporting Amend 33 to License R-28
ML20246F3881989-05-0303 May 1989
RO 12:on 881227,concentrations of I-131 & Xe-133 Discovered in Reactor Pool Water.Caused by B&W Element 204 Releasing Fission Products.B&W Contacted to Review Mfg Process.Air Samples Will Be Taken Above Pool on Monthly Basis
ML20150C6951987-12-31031 December 1987
Rept of Reactor Operations,1987
ML20236U2031987-11-24024 November 1987
Safety Evaluation Supporting Amend 32 to License R-28
ML20141N1111986-02-24024 February 1986
Safety Evaluation Supporting Amend 31 to License R-28
ML20136G8911985-11-0505 November 1985
Safety Evaluation Supporting Amend 30 to License R-28
ML20126M2631985-07-31031 July 1985
Safety Evaluation Report Related to the Renewal of the Operating License for the Training and Research Reactor at the University of Michigan.Docket No. 50-2.(University of Michigan)
ML20138L5791984-06-30030 June 1984
Low Enrichment Fuel Evaluation & Analysis Program Summary Rept for Jan 1983 - June 1984
ML20138L5731982-12-31031 December 1982
Low Enrichment Fuel Evaluation & Analysis Program Summary Rept for CY81 & CY82
ML20138L5621980-12-31031 December 1980
Low Enrichment Fuel Evaluation & Analysis Program Summary Rept for CY80
ML20138L5491980-03-10010 March 1980
Cycle 184 Reactor Operations Summary Rept for 800226-0310
ML20138L5241979-12-31031 December 1979
Low Enrichment Fuel Evaluation & Analysis Program Summary Rept for CY79
ML20148D8151978-10-13013 October 1978
Safety Evaluation Rept Supporting Amend 26 to Facil Oper Lic R-28 Concluding That an Increase from 1 Mw to 2 Mw in Maximum Allowed Pwr of Fnr w/10-plate Fuel Assemblies in E,W & Core Positions Is Acceptable
ML20148C8061978-10-12012 October 1978
Safety Evaluation Supporting Amend 25 to License R-28
ML20138L5181978-04-20020 April 1978
Revised Safety Analysis:Utilization of Intermetallic U Aluminide (UAI3,UAI4,UAI2) & U Oxide (U308) Cermet Fuel Cores in Ford Nuclear Reactor
1999-08-05
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h MICHIGAN MEMORIAL-PHOENIX PROJECT PHOENIX MEMORIAL LABORATORY FORD NUCLEAR REACTOR ANN ARBOR, MICHIGAN 48109 2100 September 17,1998 Docket 50-2 License R-28 United States Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555 Re: Notification of Unusual Event:
Slow Inward Drift of the Non-Safety Related Control Rod When in Manual Control (Corrected Copy)
The purpose of this letter is to inform you of an unusual event that recently occurred at Ford Nuclear Reactor. A letter was sent to you dated September i1,1998 regarding this unusual event.
This letter corrects an inadvertent formatting error in the September 11th letter which deleted some text.
On 11 August 1998, the swing shift operators noted that the control rod would slowly drift inwards when in manual control with the control rod lower-raise switch in neutral. The control rod was not supposed to move when the control red lower-raise switch is in neutral. The reactor was shutdown as a precautionary measure.
Facility management evaluated the event from a license and regulatory position. The control rod is
, a non-safety-related rod. The reactor safety system protects against high power and short period excursions, regardless of cause The safety analysis states that the control rod reactivity is limited to 0.6 %Dk/k to prevent a prompt criticality. Actual control rod reactivity is about 0.35 %Dk/k, well below the 0.6 %Dk/k tech spec limit. Management concluded that this unusual event was not a reportable occurrence; not a tech spec, safety analysis or significant system deficiency; and was
, 'not reportable under 10 CFR 21. It was decided that this notification would be made only because the control rod drift resulted in the slow addition of negative reactivity to the reactor.
Troubleshooting efforts were begun. The control rod lower-raise switch was removed, inspected i and cleaned, then reinstalled and tested. The four solid-state switching relays that send 120 VAC control power to the drive motor were replaced. The drift was still present. It was noted that there
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were anomalous voltage signals (less than i VAC) at the control rod drive motor wiring terminals.
These anomalous voltage signals disappeared when the drive motor wiring terminals were cleaned 4
and tightened. The control rod drift problem also went away. As a precautionary measure, the drive motor terminations for the three shim-safety rods were also cleaned and re-tightened. Restart authorization was then given by management.
On 17 August 1998, this slow inward drift of the control rod began to reoccur. Once again, the reactor was shutdown as a precautionary measure. Extensive troubleshooting efforts finally
) established that the problem was mechanical, not electrical. Anomalous voltage signals of less than one volt were still present, but were attributed to the high input impedance of the digital voltmeter being used. The slow inward drift could be duplicated even after the drive motor was physically decoupled from the drive assembly.
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Phone:(734) 764 6220 Fax: (734) 936-1571 www.umich.edu/~mmpp/
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Disassembly and study of a spare rod drive system showed that the rotating motor shaft had a .
wonn gear which engaged a large drive gear. Staff members agreed that one of the design features I of a worm to drive gear coupling was that it should not allow the drive gear to make the wonn gear spin. Since the inward control rod drift was making the control rod drive motor spin, a defect in the worm to drive gear coupling was suspected. The gear drive was opened for inspection. It was found that there was significant wear of the wonn gear, and that the worm gear was also missing a full turn of its thread. A spare worm gear - drive gear coupling was installed and tested. The drift problem did not reoccur, despite extensive exercising throughout the range of operation. The control rod drive speed was verified to still be 24 inches of travel in 45 seconds of time, the same as before. Restart authorization was then given.
The following half-cycle, during low power operations using manual rod control, the control rod i again began to display the slow inward drifting moti on with the control rod lower-raise switch in neutral. The reactor was shut down, and the control rod drive assembly was physically removed, disassembled, and the remaining parts of the gear drive inspected. Another gear cavity, located behind the worm gear cavity, was opened and inspected. The gears and bearings in this cavity were in good condition, but the cavity was essentially vacant. Reference to the facility's original <
maintenance instructions for the rod drive showed ~that this cavity was supposed to be packed with l Beacon 325 grease. After cleaning and inspecting, the gears and bearing were reinstalled, and the cavity fully packed with new grease (general purpose wheel bearing grease).
There has not been a recurrence of this problem since then.
Sincerely, I John Lee, Interim Director
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xc: Theodore Michaels, USNRC Project Manager Thomas Burdick, USNRC Region III l
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