ML20040H482
| ML20040H482 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 02/04/1982 |
| From: | Papay L SOUTHERN CALIFORNIA EDISON CO. |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8202180297 | |
| Download: ML20040H482 (2) | |
Text
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or Southern Calitbrnia Edison Company g5 RO. SON 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 g pg,g uce passeosus as,.s73.Mpe February 4, 1982 Mr.
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U. S. Nuclear Regulatory Commission g
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Dear Mr. Eng'elken:
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Subject:
Docket No. 50-361 6
/;Nb San Onofre Nuclear Generating Station, Unit By letter to your office dated January 21, 1982 we transmitted a report regarding a failure of a valve coupling which we had previously reported to you as a potentially significant deficiency in accordance with 10CFR50 55(e).
Further developments have added to the corrective action we are taking regarding the reported condition.
Con-sequently, attached are twenty-five (25) copies of a supple-mental report entitled " SUPPLEMENTAL REPORT ON SHUTDOWN COOLING SYSTEM FLOW CONTROL VALVE COUPLING FAILURE, San Onofre Nuclear Generating Station, Unito 2 and 3."-
If you have any questions regarding this report, we would be happy to discuss them at your convenience.
1 Very truly yours, l
l Enclosures cc:
Victor Stello (NRC, Director I&E) l A. E. Chaffee (NRC, San Onofre Units 2 and 3) in l
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SUPPLEMENTARY REPORT ON SHUTDOWN COOLING SYSTEM FLOW CONTROL VALVE COUPLING FAILURE San Onofre Nuclear Generating Station, Units 2 and 3 INfRODUCTION By letter dated January 21, 1982, Southern California Edison trar.smitted a report regarding the failure of the coupitng which connects the valve s tem to the pneumatic valve operator on shudown cooling system (SDCS) flow control valve FV-0306 installed in San Onofre Unit 2.
That report recorded the results of investigation o f causes, analysis o f safety implications, and corrective action taken or to be taken.
This supplementary report provides additional information on corrective action which has been developed as a result of testing by the valve manufacturer.
CORRECf1VE ACTION SONGS-2 Shutdown Cooling Flow Control Valve 2FV-0306 will be changed from remote to local-manual operation for the first fuel cycle.
Specific modifications being made to 2FV-03J6 to ensure the actuator-to-valve coupling will meet specified service requirements are as follows:
1-A coupling larger than the one that f ailed (3" rather than 2") and made of AISI 4140 heat treated steel will be used.
2-Inside corner s tress concentration in the coupling, associated with use of a square broach, will be reduced by chamfering the corners of the broach.
3-The penumatic actuator will be disabled by removing the spring and spring housing.
4-rhe engagement clutch will be secured in the manual override position by installing a cover to preclude inadvertent disengagement.
5-A permanent, durable tag will be attached to the handsheel specifying the rim pull load lim t.
Ad ditionally, the "Open" "Close" direction will be clearly indicated on the handwheel.
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