05000285/LER-1979-004-01, /01T-0 on 790226:during Containment Insp After Outage,Weld Leak Discovered on Controlled bleed-off Line on Reactor Coolant Pump RC-3C.Caused by Vibration Induced Fatigue.Repairs Performed

/01T-0 on 790226:during Containment Insp After Outage,Weld Leak Discovered on Controlled bleed-off Line on Reactor Coolant Pump RC-3C.Caused by Vibration Induced Fatigue.Repairs Performed

ML19289D746
Person / Time
Site:	Fort Calhoun
Issue date:	03/08/1979
From:	Andrews R, David Jones OMAHA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19289D745	List: 05000285/LER-1979-004, Forwards LER 79-004/01T-0 05000285/LER-1979-004-01, /01T-0 on 790226:during Containment Insp After Outage,Weld Leak Discovered on Controlled bleed-off Line on Reactor Coolant Pump RC-3C.Caused by Vibration Induced Fatigue.Repairs Performed
References
LER-79-004-01T, LER-79-4-1T, NUDOCS 7903140315
Download: ML19289D746 (4)

LER-1979-004, /01T-0 on 790226:during Containment Insp After Outage,Weld Leak Discovered on Controlled bleed-off Line on Reactor Coolant Pump RC-3C.Caused by Vibration Induced Fatigue.Repairs Performed

Event date:
Report date:
2851979004R01 - NRC Website

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60 61 OOCKET NUMSER 68 69 EVENT OATE 74 75 REPORT D ATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h o 2 l During containment inspection following a unit outage a veld leak vas discovered I

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I en the controlled bleed-off line on Reactor Coolant Pump RC-30.

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l vas determined to be approximately 0.2 gallons per minute vell within Technical l

Ioisi Specification 2.1.h leakage limits. The unit was placed in a hot shutdown l

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D. Jones /R. Andrevs PHONE:

NAME OF PREPARER

LER 79-00h C=aha Public Power District Fort Calhoun Station Unit No.1 Docket No. 05000285 Attachment No. 1 Analysis of Occurrence / Safety Analysis The reactor coolant system leak experienced was well within Tech-nical Specification 2.1.h, hence, a limiting condition for operation was not violated.

Since this failure did result in " abnormal degradation" of the reactor coolant pressure boundary and was not the result of packing or gasket leakage, it has been classified as a reportable occurrence.

The leakage experienced was less that 0.2 gym and did not contribute to any detectable increase in containment activity or dev point.

Since all activity released was confined to the containment structure, the health and safety of the public was not endangered by this occurrence.

LER 79-00h C=aha Public Power District Fort Calhoun Station Unit No.1 Docket No. 05000285 Attachment No. 2

Corrective Action

1.

Prior to plant startup, the veld failure on RC-3C controlled bleed-off line was repaired.

2.

EIAR 76-50 was submitted as a result of two previous failures of this type on RC-3C over two years ago.

Controlled bleed-off line restraint was evaluated at that time and all required restraints were verified to be properly installed.

EEAR FC-78-63 has been submitted to investigate vibration on Reactor Coolant Pump RC-3C which is inducing vibration on the controlled bleed-off piping.

1

., s LER 79-00h Omaha Public Power District Fort Calhoun Station Unit No. 1 Docket No. 05000285 Attachment No. 3 Failure Data This is the third instance where veld leakage has occurred on Reactor Coolant Pump RC-3C controlled bleed-off line.

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