ML19317F911

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Forwards RO-76-11.Provides Details
ML19317F911
Person / Time
Site: Rancho Seco
Issue date: 08/20/1976
From: Mattimoe J
SACRAMENTO MUNICIPAL UTILITY DISTRICT
To: Engelken R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML19317F912 List:
References
NUDOCS 8002210633
Download: ML19317F911 (2)


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'% SACRAMENTO M'NNICIPAL-UTILITY DISTRICT C 1708 59th Street. Bow 15830. Sacramento. Cah m

4-August 20, 1976

.Mr.-R. H.'Engelken

-Director of Regulatory Operations NRC: Operations 0ffice, Region V

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1990 N. California Boulevard Walnut Creek Plaza, Suite 202 L

Walnut Creek, California. 94596

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' Re: Operating License DPR-54

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Docket No. 50-312 Reportable Occurrence 76-11 d

Dear Mr. Engelken:

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In accordance with Technical Specifications for-Rancho Seco Nuclear Generating Station, Section 6.9.1, and Regulatory Guide 1.16, Revision 4,

Section C.2.b.4, the. Sacramento Municipal Utility District is hereby reporting
1 the following Reportc.ble Occurrence as RO 76-11.

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On August 5,1976, a: leak was reported from a weld connecting the

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nipple.on' a vent-valve with a saddle on the outlet of the "B" Decay llent

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Cooler. Leakage has been experienced. from this valve in the past, with efforts to determine'the cause and to prevent recurrence being unsuccessful. i;

- The Plant : Review Committee had reviewed the previous instances of leakage' and determined that they were not reportable under ~ the provisions of Regulatory' Guide 1.16. - Mr. F. Wenslawski of your office has since requested that leakage of radioactive. fluids through welds be reported.

Several attempts have been made to repair the weld, including grinding out the crack and rewelding. completely. grinding out the saddle and rewelding.

-and replacing the saddle. ' Vibration readings near' the weld did not seem to indicate excessive' levels. -To r'epair the present leak, a new saddle will.be welded on.the pipe and the' vent valve line will be extended to a nearby column f_

where:the_ valve ~and line will'be. secured. This-will eliminate vibration of

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the valve as a possible cause and prevent excessive torque-from being applied ~-

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Lto'the vent' cap,'which also could have. initiated'the cracking. The removed saddle-nipple section will b'e "sent..to a testing laboratory in an' attempt to L

determine'the failure mode.

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8002210 3

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- COPY SENT REGION 3

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Mr. R. H.'Engelken 2-August 20, 1976 i

If'the results of this testing indicate the cause of the cracking

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and/or if~any further corrective action becomes necessary, a supplemental i.

- report will be filed.

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Respectfully submitted, l

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. J. Mattimoe I

Assistant General Manager i

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and Chief Engine'er

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