ML17266A064

LER 79-011/03L-0 on 790316:during Power Operation, 1C Charging Pump Found to Have Cracked Pump Casing.Caused by Vibration Due to Suction Cavitation on Pumps.Suction Dampening Devices Will Be Installed

ML17266A064
Person / Time
Site:	Saint Lucie
Issue date:	04/13/1979
From:	Schoppman M FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML17206A740	List: ML17206A739 ML17266A064
References
LER-79-011-03L, LER-79-11-3L, NUDOCS 7904230321
Download: ML17266A064 (3)

Text

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leakage thru the'crack v'as quite minor and contained by the rad. Traste.

management system. Due to. design redundancy, the remaining thoro cbarging pumos in service can pump . the required design capacity of the Ctl(CS and

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REPORTABLE OCCURRENCE 335-79-11 LICENSEE EVENT REPORT PAGE Th'0 Additional Cause Descri tion and Corrective Action:

An engineering evaluation of the Charging and Volume Control System (CVCS) operation and vibration was performed in September of 1977.

This evaluation suggested that suction cavitation may be the cause of vibration within the system. Based on this, plans were made to install pulsation dampening devices (accumulators) on the suction of each charging pump. Installati.on was scheduled to be performed during the 1980 refueling shutdown.

On 9-2-78, lA charging pump was found to have a cracked casing (See LER 335-78-34). The procurement of materials to install the suction

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pulsation dampening devices was placed on an expedited basis. The cracked casing was replaced with a new casing on 1-9-79.

Presently, the plant is shut down for the 1979 refueling outage. Preliminary work on the CVCS 'will be performed during this refueling outage to enable installation of the pulsation dampening devices during full power operation later this year. During power operation, only one charging pump at a time will have to be removed from service to install the pulsation dampening device on that pump. This will:allow installation during power operation and still fulfillTechnical Specification, require-ments for the CVCS. Delivery time for the pulsation dampening devices is presently scheduled for June, 1979. The devices will be installed shortly after delivery.

1C charging pump casing will be replaced with a new casing prior to startup following the 1979 refueling outage.

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