05000369/LER-1981-051, Forwards LER 81-051/03L-0.Detailed Event Analysis Encl

Forwards LER 81-051/03L-0.Detailed Event Analysis Encl

ML20009C227
Person / Time
Site:	McGuire
Issue date:	05/12/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20009C228	List: 05000369/LER-1981-051, Forwards LER 81-051/03L-0.Detailed Event Analysis Encl 05000369/LER-1981-051-03, /03L-0:on 810412,while in Mode 3,initial Fuel Loading,Train a of Solid State Protection Sys Declared Inoperable Due to Indications on Status Panel.Caused by Two Defective Circuit Boards.Boards Replaced
References
NUDOCS 8107200391
Download: ML20009C227 (2)

LER-1981-051, Forwards LER 81-051/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3691981051R00 - NRC Website

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DUKE POWER COMPANY

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May 12, 1981 Tcua o c:^ u 7o.

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'I Mr. J. P. O'Reilly, Director T 7;x U. S. Nuclear Regulatory Commission g[ Li (/,

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Atlanta, Georgia 30303 7

JUL 171981*- T Re: McGuire Nuclear Station Unit 1 4 k u>s.g Docket No. 50-369 e

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Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report R0-369/81-51. This report concerns Train A of the Solid State Protection System being taken out of ser-vice. This incident was considered to be of no significance with respect to the health and safety of the public.

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William 0. Parker, Jr -

RWO/djs Attachment Mr. Bill Lavalee 4

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Director Office of Management and Program Analysis Nuclear Safety Analysis Center U. S. Nuclear Regulatory Commission Post Office Box 10412 Washington, D. C.

20555 Palo Alto, California 94303

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8107200391 810512 PDR ADOCK 05000369 S

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INCIDENT REPORT REPORT NUMBER: 81-51 REPORT DATE: April 29, 1981 OCCURRENCE DATE: April 12, 1981 FACILITY: McGuire Unit 1, Cornelius, N.C.

IDENTIFICATION OF OCCURRENCE,: Solid State Protection System (SSPS) train LA was taken out of service for maintenance. This is reportable pursuant to Technical Specification 3.3.2.

CONDITIONS PRIOR TO OCCURRENCE: Mode 3, Hot Standby DESCRIPTION OF OCCURRENCE: SSPS train LA was declared inopcrable several tLaes on April 12, 1981 and April 13, 1981 for troubleshooting. Erroneous permissive block indications appeared on the status panel in the Control Room. Train A was declared inoperable at 1723 hours0.0199 days <br />0.479 hours <br />0.00285 weeks <br />6.556015e-4 months <br /> on April 12, 1981; operable at 1904 hours0.022 days <br />0.529 hours <br />0.00315 weeks <br />7.24472e-4 months <br /> on April 12, 1981; inoperable at 1945 hours0.0225 days <br />0.54 hours <br />0.00322 weeks <br />7.400725e-4 months <br /> on April 12, 1981; and operable at 1520 hours0.0176 days <br />0.422 hours <br />0.00251 weeks <br />5.7836e-4 months <br /> on April 13, 1981.

APPARENT CAUSE: Circuit board A506 had a temperature related defect. Circuit board 505 may also have been defective.

ANALYSIS OF OCCURRENCE: A defective circuit board in the logic (number 505) was discovered in the SSPS cabinet. The circuit board was replaced and the system was put back into service and checked for proper operation. Train A pertormed correctly and the erroneous indications did not reappear on the control board. The system was declared operable. As soon as the circuit boards in the cabinet reached normal operating temperature, the problem reappeared and the system was again declared inoperable (1945 hours0.0225 days <br />0.54 hours <br />0.00322 weeks <br />7.400725e-4 months <br />, April 12, 1981).

In the morning (April 13, 1981) further testing identified another circuit board defective (Isolator Card A506). The defect was temperature related. The circuit board was replaced and the train put back into service.

After the system had operated satisfactorily for several hours, it was 1

declared operable.

SAFETY ANALYSIS

Train B of SSPS remained operable throughout the period of naintenance on train A.

If an accident had occurred, train B would have initiated the appropriate action.

Since train B is totally redundant, the safe operation of the atation and the health and safety of the public were not affected.

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CORRECTIVE ACTION

The defective circuit boards were replaced and the system returned to service.

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