ML20005A789

Forwards LER 81-002/01T-0.Detailed Event Analysis Encl

ML20005A789
Person / Time
Site:	Oconee
Issue date:	02/25/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20005A790	List: ML20005A789 ML20005A793
References
NUDOCS 8107010267
Download: ML20005A789 (3)

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DUKE PowEn COMPANY Powra Butunno 422 Sourn Cacacu Srazzr. CaAnt.orTr. N. C. asa4a

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WILLIAM O. PAR M ER, J R.

• ICL CP=c es t:AmC4704 VtC C P# css 0 Ces t sr:4- P oowe o. February 25, 1981 2724:s2 8/-006 - 0 3b Mr. James P. O'Reilly, Director j U. S. Nuclear Regulatory Commission ,,

, is 0 rietta Street, Suite 3100 ); j~5

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Atlanta, Georgia 30303

? JUN 3 01981 NA j~* r pA .g a gicuAnnG#.a3M y Re: Oconee Nuclear Station Docket No. 50-270 gb 4 Y

Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report R0-270/81-2. This report describes an incident which is considered to be of no significance with re-spect to its effect ..n the health and safety of the public.

Ve - truly yours, ,.' -

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O <a.& 0 ' 5 6-

. William O. Parker, Jr.

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JLJ:pw Attachnent cc: Director Mr. Bill Lavallee Office of Management & Program Analysis Nuclear Spfety Anslysis Center U. S. Nuclear Regulatory Commission PO Box 10412 Washington, D. C. 20555 Palo Alto, California 94303

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( ' 8107010?67 810225 gDRADOCK 05000270 PDR

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., . T DUKE POWER COMPANY OCONEE UNIT 2 Report Number: R0-270/81-2 .

. Report Date: February 25, 1981 Occurrence Date: February 11, 1981 Facility: 0 cones Unit 2, Seneca, South Carolina Identification of Occurrence: Electrical Penetration No. EMV-2 Failed to Hold SF6 Gas Charge Cond'itions Prior to occurrence: 75% FP Description of Occurrence: During the Perforaar.ce test for the Reactor.

< Building Electrical Penetration SF6 Gas Reading, it was noted that Electri-

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cal Penetration No. ENV-2 had a pressure reading of 0 PSIG. After several attempts to fill the penetration with SF6 gas, it was determined that the penetration could not be pressurized.

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i Apparent Cause of Occurrence: The apparent cause of this incident is a lear at-the interior bushing. The exact cause will be determined when Unit 2 ta shutdown to effect repairs.

4 Analysis of Occurrence: .During the period of this incident, it was determined that the outside boundary of the electrical penetration was intact. A

• 10CFR50.59 evaluation was performed, and it was determined that operation with only a single containment barrier was permissible and was not an unreviewed safety question. This evaluation and determination was supported by the Duke Power Desiga Engineering group.

Corrective Action: Based on inspection, it was determined that the leakage of SF6 gas was on the Reactor Building side. Reactor Building containment integrity was verified since one containment boundary still existed. A regulator on a SF6 gas bottle was set to approximately 5 PSIG, and left

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hooked up to the penetration to ensure a positive pressure on the penetration.

The penetration will be repaired or replaced during the next available outage.

The following surveillance program was started on February 12, 1981.

< SURVEILLANCE PROGRAM The following program will be utilized to assure monitcring of the electrical penetration No. EMV-2.

An HP-210 " pancake" probe will be attached to the sheet metal enclosure around:the penetration. Any leakage from the building through the pene-tration would concentrate in the enclosure and be detected by the p':obe..

At the present time, the activity in the containment is significantly greater

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- than the activity in the penetration room. The activity in the penetration enclosure will be monitored no less than once a day. A method of performing a more accurate and/or frequent surveillance will be evaluated. Any im-provements to the accuracy and/or frequency will be implemented.

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On a daily basis, EMV-2 will be purged with SF6 gas to prevent roisture buildup.

This surveillance program will continue until such a time as the Reactor is shutdown or the penetration is repaired.

The unit will not be operated with this situation for more than 30 days or after March 15, 1981.

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