ML19263C043

LER 79-002/03L-0 on 790101:during Normal Operation,Pump 1-RM-P-159A Tripped on Overload.Containment Particulate Sample Flow Was Lost,Rendering Inoperable 1 Reactor Coolant Leak Detection Sys,Due to Deficient Federal 1206LLT Bearing

ML19263C043
Person / Time
Site:	North Anna
Issue date:	01/29/1979
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19263C039	List: ML19263C038 ML19263C043 ML19263C044
References
LER-79-002-03L, LER-79-2-3L, NUDOCS 7902020184
Download: ML19263C043 (2)

Text

LICENSEE EVENT REPORT (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

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REPORT DAT E 7 8 t,0 61 DOCKET NUMSER 68 63 EVENT DATE EVENT oESCRIPTION AND PROBABLE CONSEQUENCES h O 2 iDuring normal operation 1-RM-P-159A trioned on overic3d and containment 6 articulate I iO l3i isample flow was lost rendering inoperable one reactor coolant leakaae detection I

[O l4 l Isystem (T.S. 3.4.6.1). Standby pump 1-RM-P-159B was started and samole flow restored.1 O s ]This event did not jeopardize the health and safety of the general public. Reportable 10161 I pursuant to T.S. 6.9.1.9.b. I O 7 l I

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33 34 36 40 di 44 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i O l A design deficiency in the Model 6 couplino driven Conde Dri-Air pumos results in the I ii ii i [ bearings overheating and seizing. The bearings and carbon var,es were reoiaced: and I i, ,7i i the coupling alignment checked and found to be proper. Bearinas removed had a broken I

, 3 l retainer and missing balls (Type: Federal 1206 LLT). Replaced with type NDH Z 99506 I i, i4 i ] bearings approved by vendor.

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NAME OF PREPARER PHONE: a,

Virginia Electric and Power Company North Anna Power Station, Unit No.1

Attachment:

Page 1 of 1 Docket No. 50-338 Report No. LER 79-02/03L-0 Description of Event: ~

On 1/1/79 during normal plant operation, a low flow alarm was received on channel RM-RMS-159 (Containment Particulate Monitor) and it was discovered that 1-RM-P-159A had tripped on overload. Standby pump 1-RM-P-159B was immediately placed in service. This malfunction is reportable as per T.S. 6.9.1.9.b.

Probable Consequences of Occurrence:

The Containment Particulate Monitoring System is used as a primary means of detecting a Reactor Coolant System leak. The system also provides a signal to secure and isolate the Containment Purge Supply and Exhaust Systems on a high-high particulate level. The Containment Gas Monitoring System (1-RM-RMS-160) was operable to provide an isolation signal and standby pump 1-RM-P-159B was operative to restore 1-RM-RMS-159 to operable status. In addition, the Contain-ment Purge and Exhaust Valves were shut at this time. Therefore, pr-]tection was available and the health and safety of the general public were not jeopardized.

Cause of Occurrence:

This event was caused by failure of a FEDERAL 1206LLT bearing in the sample pump. It is believed that the bearing overheated causing the ball retainer ring to break resulting in pump seizure.

Immediate Corrective Action:

The immediate corrective action was to start the standby pump 1-RM-P-1598 which restored 1-RM-RMS-159 to operable status.

Scheduled Corrective Action:

The bearings and carbon vanes were replaced and the coupling alignment verified to be procer. 1-RM-P-159A was restored to operable status.

Action Taken to Pr vent Recurrence:

Replaced bearing with another type approved by Vendor. An engineering study to monitor the performance of this bean ing is currently being undertaken.

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