05000270/LER-1981-002, Forwards LER 81-002/01T-0.Detailed Event Analysis Encl

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: 05000270/LER-1981-002, Forwards LER 81-002/01T-0.Detailed Event Analysis Encl 05000270/LER-1981-002-01, /01T-0:on 810211,electrical Penetration EMV-2 Could Not Be Pressurized.Caused by Leak at Interior Bushing. Penetration to Be Repaired or Replaced During Next Outage
References
NUDOCS 8107010267
Download: ML20005A789 (3)

LER-1981-002, Forwards LER 81-002/01T-0.Detailed Event Analysis Encl

Event date:
Report date:
2701981002R00 - NRC Website

text

Y 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.

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February 25, 1981 2724:s2 8/-006 - 0 3b Mr. James P. O'Reilly, Director j

U. S. Nuclear Regulatory Commission

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0 rietta Street, Suite 3100 Atlanta, Georgia 30303

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Re: Oconee Nuclear Station Docket No. 50-270 gb 4

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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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. William O. Parker, Jr.

JLJ:pw Attachnent Mr. Bill Lavallee cc: Director 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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Apparent Cause of Occurrence: The apparent cause of this incident is a lear

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

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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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