ML19317F940
| ML19317F940 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 12/22/1976 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| Shared Package | |
| ML19317F941 | List: |
| References | |
| NUDOCS 8002210651 | |
| Download: ML19317F940 (2) | |
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SACRAMENTO MUNICIPAL UTILITY DISTRICT C 1708 59th Street. Box 15830. Sacramento. Cahfornia 95813:(916)452-3211 j
December 22, 1976 i
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lir. - R.. II. Engelken
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Director of Regulatory Operations y
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NRC Operations Office, Region V 1990 N. California Boulevard Ik L.$
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Walnut; Creek plaza, Suite 202
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a Walnut Crock, California 94596
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Operating License DPR-54 588 8 *
- l Docket No. 50-312 Reportable Occurrence 76-16 4 *,
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Dear Mr. Engelken:
In accordance with Technical Specifications for Rancho Seco Nuclear Cencrating Station, Section 6.9.1, and Regulatory Guide 1.16,
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Revision 4, Section C.2.b.2, the Sacramento Municipal Utility District i
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is hereby reporting the following Reportabic Occurrence as RO 76-16.
A synchronization surveillance test was being performed on the "A" diesel generator on December 6,1976.
During the testing a problem dcveloped in the speed adjuster.: circuitry. When the unit was started, adjtistments were made to obtain the proper speed.
Initially the decrease switch was " bumped".
The speed did decrease but no further adjustment could be accomplished by pushing the load decreaser pushhutton for approximately two minutes. At this time the circuitry began working normally and the test continued.
Twenty-five minutes into the one-hour test the speed was again decreased by the Contrel Raon switch.
The speed
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r, tarted and continued to decrease until the unit tripped off line.
An investigation of the trip was initiated, isolating the speed decreaser suitch as the cause. The suitch had the decreaser contacts closed and they did not open when the switch was released.
The back-tighted pushbutton, series 2100-a Roto-Tellite Switch manufactured by Master Specialties, van replaced and the generator was run to complete the,orveil-
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lance test and to verify the operability of the speed adj ustment cire"itr..
The '!B". diesel generator was availabic t hroughout the repair and test period.
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l Mr. R. 11. Engelken December 22, 1976 j
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This was the first incident of this type and appears t 2 an isolated component failure. There was no plant transient a' ited di with this occurrence.
"1 Respectfully submitted,
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'/J. ' J. Mat timoe Assistant General Manager
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and Chief Engineer
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Di rector, !!IPC (3)
Director, IE ('30)
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