05000338/LER-1979-146, Forwards LER 79-146/03L-0

Forwards LER 79-146/03L-0

ML19260C105
Person / Time
Site:	North Anna
Issue date:	12/12/1979
From:	Stallings C VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19260C106	List: 05000338/LER-1979-146, Forwards LER 79-146/03L-0 05000338/LER-1979-146-03, /03L-0:on 791116,w/unit in Refueling Shutdown, Pressurizer Level Protection Channel III Found to Be Reading Erratic & Inconsistent W/Actual Level.Caused by Defective Module Amplifier in Transmitter LT-1461
References
1129, NUDOCS 7912180564
Download: ML19260C105 (2)

LER-1979-146, Forwards LER 79-146/03L-0

Event date:
Report date:
3381979146R00 - NRC Website

text

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VIRGINIA ELECTRIC AND Powniz CoxPANY Hrcurwown.VinorxxA nonet December 12, 1979 Mr. James P. O'Reilly, Director Serial No. 1129 Office of Inspection and Enforcement P0/RMT:scj U. S. Nuclear Regulatory Commission Docket No. 50-338 Region II 101 Marietta Street, Suite 3100 License No. NPF-4 Atlanta, Georgia 30303

Dear Mr. O'Reilly:

Pursuant to North Anna Power Station Technical Specifications, the Virginia Electric and Power Company hereby submits the following Licensee Event Report for North Anna Unit No. 1.

Report No.

Applicable Technical Specifications LER 79-146/03L-0 T.S. 6.9.1.9.a.

This report has been reviewed by the Station Nuclear Safety and Operating Committee and will be placed on the agenda for the next meeting of the System Nuclear Safety and Operating Committee.

Very truly yours, N)...) di6 : f C. M. Stallings Vice President-Power Supply and Production Operations Enclosures (3 copies) cc:

Mr. Victor Stello, Director (30 copies)

Office of Inspection and Enforcement Mr. Norman M. Haller, Director (3 copies)

Office of Management and Program Analysis 1609 239 7 912180 5-(t

Virginia Electric and Power Company North Anna Power Station, Unit #1 Attachment: Page 1 of 1 Docket No. 50-338 Report No. LER 79-146/03tc0

Description of Event

During a calibration check on November 16, 1979, Pressurizer Level Protection Channel III was found to be reading inconsistent with actual pressurizer level. At 92% actual level, transm tter LT-1461 was reading approximately 80%

and at 5% actual, the transmitter was reading 10%.

ge Probable Consequences of Occurrence Pressurizer level protection channels initiate a reactor trip on high levels in 2 out of 3 channels and a safety injection on low level in 1 out of 3 channels coincident with a low pressurizer pressure.

Since the TMI incident, however, the low pressurizer level bistables have been required to be maintain-ed in the tripped condition allowing a safety injection to occur on receipt of only a low pressurizer pressure.

Because redundant Pressurizer Level Protec-tion Channels I and II were operable and in calibration, the health and safety of the general public were not affected by this event.

There are no generic implications associated with this occurrence.

Cause of Event

It is suspected that the inconsistent readings were caused by a defective electronic module amplifier in transmitter LT-1461.

Immediate Corrective Action

The level transmitter was replaced with a transmitter from Unit 2 and the faulty transmitter was returned to the manufacturer for repair.

Scheduled Corrective Action The reference leg for the particular level channel is presently being filled to allow the new transmitter to be calibrated.

When the old transmitter is received from the vendor af ter being repaired, it will be installed in Unit 2.

Actions Taken to Prevent Recurrence No further actions are required.

AA2 1609 240