05000338/LER-1979-142-01, /01T-0:on 791015,channel IV Steam Line Pressure Protection for Loop C Was Discovered to Be Swapped W/ Protection for Loop A.Caused by Incorrectly Connected Sensing Lines from Root Valves to Transmitters

/01T-0:on 791015,channel IV Steam Line Pressure Protection for Loop C Was Discovered to Be Swapped W/ Protection for Loop A.Caused by Incorrectly Connected Sensing Lines from Root Valves to Transmitters

ML19254E326
Person / Time
Site:	North Anna
Issue date:	10/29/1979
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19254E319	List: 05000338/LER-1979-142, Forwards LER 79-142/01T-0 05000338/LER-1979-142-01, /01T-0:on 791015,channel IV Steam Line Pressure Protection for Loop C Was Discovered to Be Swapped W/ Protection for Loop A.Caused by Incorrectly Connected Sensing Lines from Root Valves to Transmitters
References
LER-79-142-01T, LER-79-142-1T, NUDOCS 7910310453
Download: ML19254E326 (2)

LER-1979-142, /01T-0:on 791015,channel IV Steam Line Pressure Protection for Loop C Was Discovered to Be Swapped W/ Protection for Loop A.Caused by Incorrectly Connected Sensing Lines from Root Valves to Transmitters

Event date:
Report date:
3381979142R01 - NRC Website

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8 00 61 DOCKET NUVUEH 08 03 EVENT DATE 74 lb RE PO7T DATE 80 EVENT DESCRIPHON AND PROBABLE CONSEQUENCES h lo l 2 l l 0n October 15, 1979, while in refueling mode, the Channel IV Steam line Pressure Pro-l o

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tection for Loop C was discovered to be swapped with the Channel IV Stern line Press-

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Virginia Electric and Power Company North Anna Power Station, Unit #1 Attachment: Page 1 of 1 Docket No. 50-339 Report No. LER 79-142/01T-0

Description of Event

On October 15, 1979, while in Mode 6, the Channel IV Steamline Pressure Protec-tion for Loop C was discovered to be swapped with the Channel IV Steamline Press-ure Protection for Loop A.

This discrepancy was found while pressurizing the "C" Steam Generator to check for tube leaks.

Probable Consequences of Occurrence The consequences of this event were limited because the redundant steanline press-ure channels ll and ll1 remained operable to provide protection in both affected steamlines. As a result, the health and safety of the general public were not affected.

However, the swapped steamline pressure channels did in effect reduce the protection for steamlines A and C from a 2 out of 3 logic to a 2 out of 2 logic.

There are no generic implications associated with this event.

Cause of Occurrence The cause for the swapped protection channels was tnat during plant construction, the sensing line from the Steamline C Channel IV root valve was inadvertently connected to the pressure transmitter for Steamline A Channel IV and the sensing line f rom the root valve for Steamline A, Channel IV was inadvertently connected to the pressure transmitter for Steamline C, Channel IV.

Immediate Corrective Action

The piping from the root valves to the two transmitters has been physically changed to connect steamlines A and C with their proper pressure trai.smitter.

Scheduled Corrective Action No scheduled corrective action is required.

Actions Taken to Prevent Recurrence Sensing lines for protection channels will be reviewed to ensure that connections are made to the correct transmitters.

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