05000269/LER-1981-020, Forwards LER 81-020/03L-0.Detailed Event Analysis Encl

Forwards LER 81-020/03L-0.Detailed Event Analysis Encl

ML20033D286
Person / Time
Site:	Oconee
Issue date:	11/25/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20033D287	List: 05000269/LER-1981-020, Forwards LER 81-020/03L-0.Detailed Event Analysis Encl 05000269/LER-1981-020-03, /03L-0:on 811029,hydrogen Purge Unit Declared Inoperable Due to Substandard Heat Output from Dehumidifier Heaters.Caused by Frayed Conductor Cable Due to Suspected Thermal Embrittlement & Mechanical Vibration
References
NUDOCS 8112070491
Download: ML20033D286 (2)

LER-1981-020, Forwards LER 81-020/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
2691981020R00 - NRC Website

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Mr. James P. O'Reilly, Director Q

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101 Marietta Street, Suite 3100

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Re: Oconee Nuclear Station Docket No. 50-269

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Dear Mr. 0'failly:

Please find attached Reportable Occurrence Report R0-269/81-20. This report ie submitted pursuant to Oconee Nuclear Station Technical Specification 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 con-sidered to be of no significance with respect to its effect on the health and safety of the public.

Very truly yours,

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William O. Parker, Jr.

JIT/php At.taciunent cc: Director Records Center Office of Management and Program Analysis Institute'of Nuclear Power Operations U. S. Nuclear Regulatory Conn tssion 1820 Water Place Washington, D. C. 20555 Atlanta, Georgia 30339 Mr. W. T. Orders NRC Resident Inspector Oconee Nuclear Station

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DUKE POWER COMPANY OCONEE NUCLEAR STATION REPORT NUMBER: R0-269/81-20 REPORT DATE: Noven.ber 25, 1981 OCCURRENCE DATE: Octcber 29, 1981 FACIiJfTY; Oconee Nuclear Station, Seneca, South Carolina IDENTIFICATION OF OCCURRENCE: Oconee 1 Cold Shutdown Oconee 2 Startup in progress Oconee 3 100% FP DESCRIPTION OF OCCURRENCE: On October 29, 1981 the Hydrogen Purge Unit was declarud inoperable due to substandard heat output from the debumidifier heaters. This problem with the heater was identified during the Hydrogen Purge Unit Performance Test.

_ APPARENT CAUSE OF OCCURRENCE: The apparent cause of this event was a frayed conductor cable. The cause of the cable wear is suspected to be thermal embrittlement coupled with mechanical vibrations due to air flow.

ANALYSIS OF OCCURRTNCE: The Hydrogen Purge Unit was inoperable for only a few hours, and since the Unit would not be required until several days following a LOCA or MHA it is considered that this event did not affect the health and safety of the public. Additionally, it was determined that both Purge Unit heaters could be disabled by a single fault in the common-control circuitry or wiring.

CORRECTIVE ACTION

The frayed conductor cable was replaced and the Hydrogen Purge Unit declared operable. Wiring to the dehumidifier heaters will be modified to provide redundant circuits and independent monitoring of the heaters. Appropriate procedures will be revised to provide a more compre-hensive check of heater performance.