ML19344E575

LER 80-027/03L-0:on 800729,during Steady State Power Operation,Leak from Failed Socket Weld Found on Fitting in 1-inch Safety Injection Tank Recirculation Line.Caused by Crack Due to long-term Fatigue Attributed to Vibration

ML19344E575
Person / Time
Site:	Millstone
Issue date:	08/25/1980
From:	Harris J NORTHEAST NUCLEAR ENERGY CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19344E574	List: ML19344E573 ML19344E575
References
LER-80-027-03L, LER-80-27-3L, NUDOCS 8009020285
Download: ML19344E575 (2)

Text

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REpoR f QATE F 8 60 61 DOCKET NUM9ER tia 69 Evt1T DATE EVENT DESCRIPTION AND PROB ABLE CONSEQUENCES h l o l 21 l During steady state power operation, a leak was evident within the containment. A l "

lo t a l I containment entry disclosed a failed socket weld on a fitting in a 1 inch safety i I o !41 l injection tank recirculation line. The leak was isolated and the weld was ground out l l o 13 l l and rewelded. Similar events: 77-10 (3/21/77); 77-37 (9/17/77) [

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CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h 1i i o l l The cause of the leak was a crack caused by long term fatigue attributed to vibration. l ii iii i The long term corrective action for this recirculation line will be a stress I i,i2i l evaluation and hanger rework (if reauired) during the refueling outage. I I

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ATTACHMENT LER 80-27/3L-0 Millstone Unit 2 Docket No. 50-336 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES During steady state power operation, a leak was evident within the containment due to the frequency of pumping the contaiment sump and a slow decrease in Safety Injection Tank (SIT) Number 1 level. A containment entry disclosed a failed socket weld on a fitting in a 1 inch recirculation line. The leak was isolated and the weld was ground out and rewelded.

Similar events: 77-10 dated 3/21/77; 77-37 dated 9/16/77 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS The cause of the leak was a crack caused by long term fatigue s

attributed to vibration. The leak path was via SIT Number 1 through a leaking drain valve 2-SI-618 caused by a controller malfunction.

The fuses to 2-SI-618 were pulled to fail the valve closed. The valve is a Fisher Type 667-DBQ 1 inch diaphragm control valve rated 1500 PSI. The valve controller will be repaired during the refueling outage.

The long tenn corrective action for the recirculation line cracking will be a stress evaluation of this line and hanger rework (if required) during the refueling outage. The piping is Schedule 40S, Type 304 Stainless Steel,' ASME Class 2.

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