ML20032A762
| ML20032A762 | |
| Person / Time | |
|---|---|
| Site: | University of Missouri-Columbia |
| Issue date: | 10/27/1981 |
| From: | Alger D, Mckibben J MISSOURI, UNIV. OF, COLUMBIA, MO |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8111020345 | |
| Download: ML20032A762 (2) | |
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Research Reactor Facility UNIVERSITY OF MISSOURI Research Park Columbia, Missouri 65211 October 27, 1981 Telephone (314) 882-4211 q,g b
Director of Licensing NOV0s ISSS k U. S. Nuclear Regulatory Commission 6
g"Meute g Washington, D. C.
20555
Reference:
Docket 50. '6 t%** g~~h University of Missouri License R-103
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Subject:
Failure of Emergency Electrical Generator to Start Description On September 28, 1981, the emergency generator failed to start when the start-ing sequence was initiated by the automatic weekly exerciser.
Bec wse it was a scheduled inaintenance day, and the reactor was shutdown, no one was in the control room at the time of the failure.
It was at 1400, during a machinery routine patrol, that the " fail to start" light was discovered lit and the cranking limiter we found tripped.
The cranking limiter trip secures the starter motor if the generator fails to start within one minute.
The generator had been run normally on September 21, 1981 when it was started by the automatic weekly exerciser.
Therefore, it could be assumed that the gen-enerator was not operable during the previous seven days of operation which is a deviation from Technical Specification 3.10.a.
Analysis The emergency generator is equipped with an electric fuel pump.
This fuel pump is controlled by a switch whicn permits either " hand", or " auto" operation.
During l
routine patrols, this switch is checked in the " auto" position every four hours.
Upon examination of the switch operating mechanism, it was found that an internal mechanical stop which prevents the switch from being turned past the " auto" position was broken. This caused all contacts on the switch to be open, and prohibiting the l
electric fuel pump from running when the switch was checked in the " auto" position.
The emergency generator was started within five minutes of finding it in the tripped condition.
l The emergency generator is not required to protect the fuel cladding as analyzed l
in Hazards Summary Report Addendum 5 sections 2.4.1 and 2.5.
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' Director of Licensing-October 27, 1981 Page 2 Corrective Action The electric fuel pump control switch was disassembled, and a new mechanical stop was-installed on the cover, to prevent the switch from being able to be turned past the " auto" position.
The. generator was then tested with the fuel pump switch repaired and it per-formed satisfactorily. No change in switch design is anticipated,'since our records show the fuel pump switch was an original installation part and performed its intended function for over fifteen years,_ a reasonable Tife-time for this component.
Sincerely, j
V J. C. McKibben Reactor Manager Endorsement:
Reviewed and Approved Ch
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t Don M. Alger Acting Director JCMK:vs cc:
U. S. Nuclear Regulatory Commission c/o Document Management Branch James Keppler, Director Regulatory Operations - Region III Reactor Advisory Committee Reactor Safety Committee John H. Tolan, Radiation Safety Officer
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