ML19289D096

LER 79-002/01T-0 on 790111:control Room Located Recorder for Off Gas Radiation Monitors 17-150A&B Exhibited Anomalous Indications.Caused by Flow Blockage in Sampling Sys Flow Meter

ML19289D096
Person / Time
Site:	Vermont Yankee
Issue date:	01/25/1979
From:	Conway W VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19289D093	List: ML19289D091 ML19289D096
References
LER-79-002-01T, LER-79-2-1T, NUDOCS 7901290219
Download: ML19289D096 (2)

Text

NRC FORM 366 U. S. NUCLEAR REGULATORY COMMISSION (7 77)

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NAME OF PREPARER

VTVYS1 05000271 LER 79-2/lT EVENT DESCRIPTION AND PROBABLE CONSEQUENCES During the routine performance of obtaining an Off Gas System sample, the Control Room located recordet for the AEOG Radiation Monitors 17-lSOA&B exhibited anomalous indications. Immediate investigation by cognizant plant personnel determined that a flow disturbance had occurred in the sampling system utilized by both radiation monitors. Furthermore, it was determined that until . sampling system flow conditions could be returned to normal, both radiation monitors were inoperable. This condition was determined to be contrary to the requirements of T.S. Table 3.2.4 and preparations for an orderly reactor shutdown were initiated. T 2 necessity to perform the action specified in Note 2 of T.S. Table 3.2.4 was precluded by restoring opera-tion of the AEOG Radiation Monitors 17-150A&B within approximately one hour from event initiation. Based upon a review of Off Gas System samples obtained during and directly following this event, it was concluded that no abnormal e civicy at the SJAE's occurred and that there were no advarse consequencer to the public health or safety as a result of this event. There were no previous reportable occurrences of this type.

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS The investigation into the anomalous indications on the recceder for the AEOG Radiation Monitors 17-150A&B, resulted in the determinatior that the apparent cause of the event was due to a flow blockage in the sampling system's flow me*er. The immediate corrective action consisted of cleaning the internal components of the flow meter, reassembling and verifying satisfactory operation of the AEOG Radiation Monitoring System. No additional corrective action is envisioned at this time.

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