05000338/LER-1979-054-03, /03L-0 on 790513:charging Pump Removed from Svc to Repair Crack Inlet Piping.Caused by Bad Weld at Base of Vent Line.Crack Ground Out & Rewelded

/03L-0 on 790513:charging Pump Removed from Svc to Repair Crack Inlet Piping.Caused by Bad Weld at Base of Vent Line.Crack Ground Out & Rewelded

ML19273B930
Person / Time
Site:	North Anna
Issue date:	06/12/1979
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19273B929	List: 05000338/LER-1979-054, Forwards LER 79-054/03L-0 05000338/LER-1979-054-03, /03L-0 on 790513:charging Pump Removed from Svc to Repair Crack Inlet Piping.Caused by Bad Weld at Base of Vent Line.Crack Ground Out & Rewelded
References
LER-79-054-03L, LER-79-54-3L, NUDOCS 7906180544
Download: ML19273B930 (2)

LER-1979-054, /03L-0 on 790513:charging Pump Removed from Svc to Repair Crack Inlet Piping.Caused by Bad Weld at Base of Vent Line.Crack Ground Out & Rewelded

Event date:
Report date:
3381979054R03 - NRC Website

text

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8 tiO 61 DOCKE T NUMBE R ta 63 EVENT DATE 14 1s HE POH T D ATE 80 EVEN T DESCRIPTION AND PROB ABLE CONSEQUENCES h [ol2l l Charging pump 1-CH-P-1A was removed from service in Order to repair a crack on the I

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Consequences were limited since piping was repaired within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> as 1 allowed by the Technical Specification. 'Ihis event did not jeopardize the health and l o

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Attachment:

Page 1 of 1 Docket No. 50-338 Report No. LER 79-054/03L-0

Description of Event

It was discovered on Fby 13, 1979, that a leak had developed at the joint of the high point vent and the suction piping to the Unit I charging pump. These charging pumps are constant speed centrifugal pumps which normally provide makeup to the reactor coolant system.

Probable Consequences of Event The consequences of this event were limited.

Section 3.1.2.4 allows 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to restore a second charging pump to operable status with only one charging pump operable.

The crack in the vent line was repaired well within that time margin. Although no generic implications for Unit #2 are apparent at this time, this is undergoing further evaluation.

Cause

The cause of the crack in the weld appears to be due to a poor veld at the time of installation.

This problem has occurred previously, prior to plant opera tion, on "B" charging pump.

A defective weld was discovered in the joint between the high point vent line and the suction piping.

This defective veld was repaired and has presented no further problems (see LER/R0 78-003/03L-0).

Immediate Corrective Action

The defective veld was ground out and rewelded. The possibility of weld fatigue due to vibration was investigated.

The type of pump and the location of the support hangers preclude the possibility of excessive vibration. The occurrence of a similar weld crack on "B" charging pump (see LER/R0 78-003/

03L-0) prior to plant operation supports this conclusion.

Scheduled Corrective Action A review of plant construction records is presently underway to deterLine weld acceptability. Any further actions to be taken will be determined from this review and the actions delineated below.

Action Taken To Prevent Recurrence As this is the second occurrence of this type, the weld on the suction line vents for 1-CH-P-1C and the Unit #2 charging pumps will be inspected to insure they are not crackad.

If necessary, these welds vill be repaired.

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