05000369/LER-1981-092, Forwards LER 81-092/03L-0.Detailed Event Analysis Encl

Forwards LER 81-092/03L-0.Detailed Event Analysis Encl

ML20009G015
Person / Time
Site:	McGuire
Issue date:	06/25/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20009G016	List: 05000369/LER-1981-092, Forwards LER 81-092/03L-0.Detailed Event Analysis Encl 05000369/LER-1981-092-03, /03L-0:on 810530,auxiliary Feedwater Flow Rate Instrumentation Pegged High.Caused by Failed Transmitters. Transmitters Replaced & Calibr.Power Supply Removed & Will Be Replaced
References
NUDOCS 8108030243
Download: ML20009G015 (1)

LER-1981-092, Forwards LER 81-092/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3691981092R00 - NRC Website

text

DUKE POWER COMPANY

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June 25, 1981 an-4ees Mr. James P. O' Reilly, Director U. S. Nuclear Regulatory Commission

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101 Marietra Street, Suite 3100

[,, L Atlanta, Georgia 30303 Lins \\ "Q; Re: McGuire Nuclear Station Unit 1

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Docket No. 50-369

Dear Mr. O'Reilly:

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Please find attached Reportable Occurrence Report R 81 ).

This report concerns Technical Specification 3.3.3.6; "The Accident Monitoring Instrumen-tation Channels shown in Table 3.3-10 shall be operable." This incident was consider (l to be of no significance with respect to the health and safety of the public.

V y truly yours, 7

%u....

4, William 0.. Parker, Jr.

PBN/pw Attachments cc: Director Mr. Bill Lavallee Office of. Management & Program Analysis Nuclear Safety Analysis Center U. S. Nuclear Regulatory Commission P. O. Box 10412 Washington, D. C.

20555 Palo Alto, CA 94303 Ms. M. J. Graham Resident Inspector - NRC McGuire Nuclear Station i

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4 8108030243 610625 PDR ADOCK 05000369 S

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McGUIRE NUCLEAR STATION INCIDENT REPORT LER/R0 Report Number:

81-092/03L-0 Report Date:

June 25, 1981 Occurrence Date: May 30, 1981 Licensee:

Duke Power Company Facility: McGuire Unit 1, Cornelius, N. C.

Docket No.:

05000369 Identification of Occurrence:

The Auxiliary Feedwater Flow Rate Instrumentation for Accident Monitoring was declared inoperable.

Condition Prior to Occurrence: Mode 3, Hot Standby Description of Occurrence: On May 30, 1981 at 0900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br />, a work request was initiated to troubleshoot the Steam Generator (S/G) "D" Auxiliary Feedwater Flow Instrumentation failure. The flow gauge indicater in the Control Room was pegged high. At 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> that same day, the plant was entering Mode 3 from Mode 4, hence, the instrument was declared incperable.

This was a reportable incident pursuant to Technical Specification 3.3.3.6.

Apparent Cause of Occurrence:

The S/G "D" Auxiliary Feedwater Flow Monitoring Instrumentation became inoperable due to failed transmitters.

One transmitter (Rosemount, Model 1151) was sending a faulty 74 milliamp signal, and another transmitter (Barton 386A) had burned resistors on its circuit board.

Analysis of Occurrence:

On May 30, 1981 at 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />, the plant was entering Mode 3 from Mode 4.

The S/G "D" Auxiliary Feedwater Flow Instrumentation was pegged high, hence, it was declared inoperable.

Repair work immediately began on the equipment and it was found that the Rosemount transmitter was sending a 74 milliamp signal. The transmitter was replaced since it could not be cali-brated.

The Barton transmitter, which sends a signal to the Control Room in-dicator, was found to have burned resistors on its circuit board. A similar type of transmitter from Un'.t 2 was transferred to Unit 1 and the transmitter waa replaced. At that time the plant had dropped down to Mode 4 from Mode 3 due to a.non-related reason. When the Barton transmitter was placed in service, the same components were burned.

This transmitter was replaced 4 times but all of them were burned the same way.

It was suspected that the power sopply of the transmitter may had been causing the problem, hence, the power supply was taken out.

The transmitter was also replaced.

Safety Analysis

The auxiliary feedwater flow transmitters are used to provide indications for accident monitoring.

They da not provide controls or interlocks to the pumps and valves of the Auxiliary Feedwater System.

If the plant had been at normal operation, and a normal or abnormal shutdown was required, the inoper-ability of these instruments would not have affected the Auxiliary Feedwater System in providing and maintaining its necessary functions. Therefore, the plant's safe operation and the health and safety of the public were not affected by this incident.

LER/R0 Report Number 81-092/03L-0 Page 2

Corrective Action

The Rosemount transmitter was replaced and calibrated per procedure, " Calibration Procedure for Rosemount Models 1151 GP, 1151 DP, and 1151 AP Pressure Transmitters". The Barton transmitter was also replaced with a similar type of transmitter from Unit 2 and was calibrated. The power supply for the Barton transmitter will be replaced.

The plant was brought down to Mode 4 from Mode 3 within the required time limit specified in the action statement of Technical Specification 3.3.3.6.

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