05000338/LER-1979-113-03, /03L-0:on 790912,pressurizer Level Channel II Gave Erratic Indication on Control Board.Cause Unknown.Testing Revealed No Problems

/03L-0:on 790912,pressurizer Level Channel II Gave Erratic Indication on Control Board.Cause Unknown.Testing Revealed No Problems

ML19209C454
Person / Time
Site:	North Anna
Issue date:	10/12/1979
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19209C450	List: 05000338/LER-1979-113-03, /03L-0:on 790912,pressurizer Level Channel II Gave Erratic Indication on Control Board.Cause Unknown.Testing Revealed No Problems 05000338/LER-1979-114-03, /03L-0:on 790912,temp at Top Corner of Steam Generator Support Exceeded Tech Spec Limit.Caused by Heaters Being Left on Too Long When Control Resistance Temp Detector Failed to Cycle Heaters Automatically ML19209C449
References
LER-79-113-03L, LER-79-113-3L, NUDOCS 7910150587
Download: ML19209C454 (2)

LER-1979-113, /03L-0:on 790912,pressurizer Level Channel II Gave Erratic Indication on Control Board.Cause Unknown.Testing Revealed No Problems

Event date:
Report date:
3381979113R03 - NRC Website

text

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LICENSEE EVENT REPORT CONTROL BLOCK: l l

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EJ 61 DOCif,ET NUM8 ER 68 69 EVENT DATE 74 75 REPOHT DATE 60 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h o

2 On September 12, 1979, during Mode 1 operation, Pressurizer Level Channel II (LI-1460) l

gave erratic indication at the control board. The channel was placed in the tripped I

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l condition and declared inoperable.

Pressurizer Level Channels I and III remained I

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j o j s j l operable to initiate a high level reactor trip if required, therefore the health and l

l0 ls i l safety of the general public were not affected by this event. Reportable pursuant l

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40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i10 IThe cause for the erratic indicatinn it unknnwn at thic tira-Pressurizer Level I

l Channel II was placed in the tripped condition and the loop was calibrated and func-I i

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,, if] ltionally tested but no problems were found. The channel was returned to service and l it iunctioned properly.

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Virginia Electric and Power Company North Anna Power Station, Unit #1

Attachment:

Page 1 of 1 Docket No. 50-338 Report No. LER 79-ll3/03L-0 Descriction of Event On September 12, 1979, during Mode 1 opt.. Lion at 71% power, Pressurizer Level Channel II (LT-1460) gave erratic indication in the control room. The channel was placed in the tripped condition and declared inoperable.

Probable Consequences of Occurrence The consequences of this even; were limited because Pressurizer Level Channels I and III both remained operable to initiate a high level reactor trip if required. As a result, the public health and safety were no affected by this event. At present, this incident does not appear to be a generic instrument problem.

Cause of Occurrence The cause for the erratic behavior of level indicator LI-1460 is not known at this time.

Immediate Corrective Action

Pressurizer Level Channel II was placed in the tripped condition and the loop was recalibrated and functionally tested with no problems encountered.

The channel was then returned to operable status where it functioned properly without erroneous indication.

Scheduled Corrective Action Pressurizer level indicator LI-1460 is being closely monitored to ensure proper continued operation.

Actions Taken to Prevent Recurrence No further actions are required at this time.

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