ML19317F988
| ML19317F988 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 08/13/1976 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| Shared Package | |
| ML19317F989 | List: |
| References | |
| NUDOCS 8002210691 | |
| Download: ML19317F988 (2) | |
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SACRAMENTO MUNICIPAL UTILITY DISTRICT C 170s 59th street. Box 15830. sacramento, cahfornia 95813;(91,6) 452 3211 i
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August 13, 1976 Mr. R. H. Engelken h.
. Director of Regulatory Operations NRC Operations Office, Region'V 1990 N. California Boulevard !
Walnut Creek Plaza, Suite 202
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Walnut = Creek, Ca.
94596 Re: Operating License DPR-54 Docket No. 50-312-
-Reportable Occurrence 76-9 c
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Dear Mr. Engelken:
N In accordance with Tedmical Specifications for Rancho Seco
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Nuclear Generating StaW7., Section 6.9.1, and Regulatory Guide 1.16, Revision '4, Section' C.2.b.2, the Sacramento Municipal Utility District
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is hereby reporting the following Reportable Occurrence as R0-76-9.
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~On' July 15, 1976, an attempt was made to start'the "B" Diesel
. Generator to perform the monthly surveillance testing as required by Technical Specifications, Section'4.6.1.
This attempt. failed due to an improper bus alignment which prevented a manual Control Room start
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.but would not prevent a safety features start. After corrections were i.',
made to the bus alignment, another attempt was made to start the' diesel,
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which also failed. No cause could be found for the failure, therefore, another start attempt _ was made, which was successful.
- The unit was.in cold. shutdown for main generator repairs -at the time of the diesel generator testing. However, the "A" Diesel Generator was tested and determined-operable throughout the period that the "B" Generator was out of service. With the generator out of service due to the. problems experienced with starting, an in-depth testing program was n
initiated. The diesel failed to start on July 16 in a manner similar to the day before, and checks of relays, auxiliary units, time delays, and
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similar. items-failed _to reveal ~any identifiable ccms.
Since all fail-
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ures-experienced came on attempted-starts from.the Control Room, a check of'the circuitry unique to a Control Room start' was made..Three relays
'e in :the circuit _ were replaced,1 however, no abnormalities 'were found, either in the relays during bench -testing or'any other components in t.he circuit.
Attempts were made to duplicate the failure.to-start by quichi.y pressing
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- and releasing tho' Control Room start button.
This action did not produce d,
. similar start failures, therefore, it was determined that this was not-
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9 '.' E i. E' d I R i tf $ Y 3 T f3' S E R V ! N G MORE
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-\\ j Mr.LR. H. Engelkin August 13, 1976
~ A Special Test -Procedure was being run during this period to deter-mine.the starting capacity of the air start systems. The procedure was alteredLto initiate the' starts from the Control Room to-allow further test-
[i ing of the B Generator. On July 23, after the first start, the diesel was
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shutdown by a "maintenancc J stop".
It was not recognized at that time that
-a 15' minute delay is necessary following a " maintenance stop" before a manual restart :from the Control Ibom is possible.
This caused the next
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start attempt to fail. It is'possible that this situation could have
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caused the unidentified failure to start on July 15, but would not have
.been the cause of the failure on July 16.
On July 26 the Special Test Procedure was completed, with the "B" Diesel Generator starting 13 times from the Control Room without failure.
df No cause could-be 'found to explain the failure of the "B" D$csel Generator.co start. A 1 gallon' sample of fuel oil from the day tank re-vealed 'no water, however, precautions will be. taken to prevent this from J'
- being a factor in diesel failures. The dicsci started 13 times without any-recurrence of.the Itoblem, and therefore, was declared to be in service.
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J Ificny recurrence of this unidentified problem is observed, detailed investigations and correctiva actions will be instituted.
Respectfully,
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Mattimoc-Assistant General Manager and Chief Engineer-
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