ML20010F822

Forwards LER 81-011/03L-0

ML20010F822
Person / Time
Site:	Oconee
Issue date:	09/04/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20010F823	List: ML20010F822 ML20010F828
References
NUDOCS 8109110378
Download: ML20010F822 (2)

Text

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Mr. James P. O'Reilly, Director 8 9\ ,

U. S. Nuclear Regulatory Commission N(L ') T 0 r tta Street, Suite 3100 SEP 101981 > "d Atlanta, Georgia 30303 M W8"*

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-Re: Oconee Nuclear Station f s\

Docket No. 50-270 ,yv #:

Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report R0-270/81-11. This report is submitted pursuant to Oconee Nuclear Station Technical Specifica-tion 6.6.2.1.b(2). which concerns operation in a degraded mode permitted by a limiting condition for operation, and describes an incident which is considered to be of no significance with respect to its effect on the health and safety of the public.

Very truly yours, frt )

' s William O. Parker, Jr.

JFK/php Attachment Mr. ",ill Lavallee cc: Director Office of Management & Program Analycis Nuclear Safety Analysis Center U. S. Nuclear Regulatory Commission P. O. Box 10412 Washington, D. C. 20555 Palo Alto, California 94303 Mr. F. Jape Resident Inspector-NRC Oconee Nuclear Station 1 62%

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DUKE POWER COMPANY OCONEE NUCLEAR STATION UNIT 2 REPORT NUMBER: R0-?70/81-ll REPORT DATE: September 4, 1981 OCCURRENCE DAE : August 6, 1981 FACILITY: Oconee Unit 2, Seneca, South Carolina IDENTIFICATION OF OCCURRENCE: RCS Subcooling Margin Monitor inoperable due to Operator Aid Computer being out of service.

CONDITIONS PRIOR TO OCCURRENCE: Oconee 2, 100% FP DESCRIPTION OF OCCURRENCE: On August 6, 1981, at 1409, and then again on August 7, 1981, at 2330, the Oconee Unit 2 Operator Aid Computer was out of service. This was due to erratic readings of points in the analog system the first tine and erratic printing on the alarm typer the second time.

This constitutes operation in a degraded mode per Technical Specification 3.1.12.l(d) since both RCS Subcooling Margin Monitors were inoperable without a backup method for determining subcooling margin for temperatures outside the TH narrow range indication (520 F to 6200F).

APPARENT CAUSE OF OCCURRENCE: A bad AGRA2 group relay board and matrix card apparently caused the first computer malfunction. An apparent cause was not determit. 4 for the second ccmputer malfunction which was cleared after shutting dc.n and restarting the computer.

ANALYSIS OF OCCURRENCE: Technical Specificatior '.1.12.l(d) states that if both subcooling monitors are inoperable, then restore one monitor to operable status within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. In both cases the computer was restored to an operable status well within the time permitted. These incidents did not affect the operating status of Oconee Unit 2. Thus, the health and safety of the public were not affected.

CORRECTIVE ACTION: The first computer malfunction was corrected by replace-ment of two AGRA2 group relay boards and one matrix card. The second com-puter malfunction was cleared by performing a restart of the computer. A procedural change has been made to provide the operator with backup method for determining subcooling margin using a voltmeter to determine wide range TH *

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