ML20202H409

Monthly Operating Rept for Dec 1997 for Univ of Mo Research Reactor

ML20202H409
Person / Time
Site:	University of Missouri-Columbia
Issue date:	12/31/1997
From:	MISSOURI, UNIV. OF, COLUMBIA, MO
To:
References
NUDOCS 9802200383
Download: ML20202H409 (3)

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UNIVERSITY OF MISSOURI RESEARCH REACTOR OPERATIONS MONTHLY

SUMMARY

DECEMBER 1997 Prepared by: j Operations Staff 0 f

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December 1997 The reactor operated continuously in December with the following exceptions: five shutdowns for scheduled maintenance, refueling, anNor aux trap sample changes; four unscheduled shutdowns.

On December 8, a reactor scram occurred during a normal startup when an electrical short to -

ground was produced in the yellow leg " white rat" scram monitor while it was being worked on by an electronics technician. Electronics technicians performing the work on the scram monitors know not to troubleshoot the monitor while the reactor is operating. The scram occurred because of f

mi+ communication between the electronics technician and the shift supervisor.

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On December 9, a nuclearinstrument Channel #4 high power scram occurred while operating at 10 MW in automatic control. The cause for this scram could not be readily determined, but was believed to involve an actual reactivity insertion. This event falls under the Technical Specification definition of an abnormal occurrence because it apparently involved an unanticipated significant change in reactivity [T.S.1.1.cl. A Licensee Event Report, as required by Technical Speci6 cation l 6.1.h(2), was submitted to the NRC on January 8, describing the event, its evaluation, and follow-l up actions. The reactor was subsequently restarted on December 9.

On December 21, a Channel #4 (wide range monitor) high power scram occurred during a normal startup. No actual high power was indicated on any other instrumentation. The most likely cause was a momentary open or high resistance in the Channel #4 amp'i0er feedback loop associated with the range switch and the picoammeter relays. Electronics technicians removed, cleaned, checked, and reinstalled the range switch. A normal startup was then completed with no recurrence of this problem.

t On December 28, a reactor loop low now scram occurred when primary pump 501B tripped off.

Electronics technicians found and replaced a failed K2 relay coil in the control circuit for this pump.

The pump operated satisfactorily and the reactor was returned to normal operation.

UNSCHEDULED SHUTDOWNS Date No. Tm Cnuse 12/08/97 1071 Scram Electrical short to ground in scram monitor 12/09/97 1072 Scram Channel #4 high power 12/21/97 1073 Scram Spurious Channel #4 high power 12/28/97 1074 Scram Primary pump 501B tripped oft

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OPEILATIONS SUMMAltY llOURS OPERATED TIIIS POstlOD 660 TOTAL IIOURS OPERATED 208,711 110URS AT FULL POWER TIIIS PERIOD 657 TOTAL liOURS AT FULL POWER 205,627 INTEGRATED POWER Tills PERIOD 274 MWD TOTAL INTEGRATED POWER 79,829 MWD MAINTENANCE ACTIVITIES 12/01/97 Refueled removed core 97 52, loaded core 97-53, 12/08/97 Refueled - removed core 97 53, loaded core 97-54. Replaced equalize /ficat potentiometers and switch on the UPS.

12/09/97 Refueled - removed core 97-54, loaded core 97-55.

12/15/97 Refueled removed core 97 55, loaded core 97 56, 12/21/97 Refueled removed core 97-56, loaded core 97-57.

12/28/97 Refueled moved core 97 57, landed core 97-58. Replaced K2 relay in control circuit for P501 ..eplaced a resistor in NI Channel #3 circuit drawer.

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