ML19319D998
| ML19319D998 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 11/04/1977 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| Shared Package | |
| ML19319D999 | List: |
| References | |
| NUDOCS 8003270709 | |
| Download: ML19319D998 (1) | |
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(1 SNUC s.s SACRAMENTO MUNICIPAL UTILITY DitTRICT C 6201 S Street. Box 15830. Sacramento. Califorma 95813; (916) 452 3211 November 4,1977 f%
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'T Director of Regulatory. Operations ATTN:
Mr. R. H. Engelken
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1990 N. California Boulevard
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Walnut Creek Plaza, Suite 202 3
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Walnut Creek, California 94596
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Re: Operating License DPR-54 Docket No. 50-312 A b,"a
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Reportable Occurrence 77-13
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Dti Dear Mr. Engelken.
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In accordance with Technical Specifications for Rancho Seco, Nuclear i.,
Generating Station, Section 6.9.1 and Regulatory Guide 1.16, Revision 4, Section C.2.b.2, th ento Municipal Utility Distri:t is hereby reporting c
the folloviag as RO 77-1 On October 4, 1977, while the plant was shut down for refueling, the
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Reactor Building was being pressurized in preparation for an Integrated Leakage
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(V Rate Test. During this pressurization it was noted that the Surge Tank levels in Loop A and Loop B Nuclear Service Cooling Water System were both rising, indicating leakage in one or more emergency coolers in each NSCW loop. The effects of this phenomenon on the ILRT will be addressed in the su - ry technique report of that test.
t' To determine the actual cause for air leakage into both NSCW Systems, each system was pressurized and inspected. It was determined that the high point vent on Emergency Cooler A was leaking. This vent was capped and the vents on the other three coolers also were capped as a precautionary measure to prohibit any additional leakage. It was also determined that leakage was occurring through a head gasket on Emergency Cooler D as a result of some loose head gasket nuts.
These nuts were retorqued and the head gasket nuts for the other three coolers checked for proper tightness. As a result of the potential gas leakage into Emergency Coolers A and D resulting in a potential
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degradation of cooling performance, it was determined that this item was reportable.
There was no plant transient or shutdown as a result of this occurrence.
r Respectfully submitted, 1
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. Mattimoe J
Assistant General Manager c.
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T and Chief Engineer
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JJM:RJR: sal Attach.
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cs: Director, MIPC (3)
Director, IE (30)
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