05000369/LER-1981-065, Forwards LER 81-065/03L-0

Forwards LER 81-065/03L-0

ML20005A085
Person / Time
Site:	McGuire
Issue date:	05/21/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20005A086	List: 05000369/LER-1981-065, Forwards LER 81-065/03L-0 05000369/LER-1981-065-03, /03L-0:on 810422,while in Mode 3 Initial Fuel Loading,Containment Floor & Equipment Sump Level Indicators in Control Room Failed to Zero Scale Position & Ac Power Supply Was Lost.Caused by Disconnected Wires
References
NUDOCS 8106290357
Download: ML20005A085 (1)

LER-1981-065, Forwards LER 81-065/03L-0

Event date:
Report date:
3691981065R00 - NRC Website

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f t' 4pase*et:AetA 70 sec. *#eowerio-May 21, 1981 ars-.oss Mr. James P. O'Reilly, Director U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303 Re: McGuire Nuclear Station Unit 1 Docket No. 50-369

Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report RO-369/81-65. This report concerns the Containment Sump Level and Flow Monitorf ng System being declared inoperable. This incident was considered to be of na significance with re-spect to the health and safety of the public.

Very truly yours, ft)l William O. Parker, Jr.

RWO:pw Attachment cc: Director Mr. Bill Lavallee Office of Management & Program Analysis Nuclear Safety Analysis Center U.S. Nu;1.ar Regulatory Ccemission Post Office Box 10412 Washington, D. C.

20555 Palo Alco, CA 94303 Ms. M. J. Graham Resident Inspector - NRC g< lM McGuire Nuclear Station O

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McGUIRE NL f. EAR STATION INCIDENT REPORT Report Number: 81-65 Report Date: May 12, 1981 Occurrence Date: April 22, 1981 Facility: McGuire Unit 1, Cornelius, N. C.

Identification of Occurrence: The containment sump level and flow monitoring system was declared inoperable.

Condition Prior to Occurrence: Mode 3, Hot Standby Description of Occurrence: On April 22, 1981 at 2010 hours0.0233 days <br />0.558 hours <br />0.00332 weeks <br />7.64805e-4 months <br />, the Containment Floor and Equipment Sump Level Indicators in the Control Room failed to the zero scale position.

The 120V AC power supply to their appropriate trans-mitters was lost. The Shift Supervisor declared this system inoperable and was therefore reportable pursuant to Technical Specification 3.4.7.1.

Apparent Cause of Occurrence: The Containment Floor and Equipment Sump Level Indicators' failure was due to the loss of AC Power Supply to the Waste Pro-cessing Panel. The Containment Floor and Equipment Sump Level Transmitters receive their 120V AC Power from the Waste Processing Panel.

Analysis of Occurrence: On the evening of April 22, 1981, the power supply for the Interim Radwaste Pipe Trench Sump Pump A from the Waste Processing Panel to the lighting panelboard (RWL) was being relocated.

The work des-cription was to change the 120V AC source from breaker SKA-48 to brsaker RWL-42.

However, SKA-48 was the feeder breaker for the Waste Processing Panel so that when the wires were disconnected, the containment sump level transmitters were deenergized. This caused the level indicators to fail in the zero scale position.

The lifted wires on breaker SKA-48 (no tags) were reconnected.

Upon re-storing power to the Waste Processing Panel, the containment su=p level and monitoring system was back in normal operation and declared operable on April 23, 1981 at 0045 hours5.208333e-4 days <br />0.0125 hours <br />7.440476e-5 weeks <br />1.71225e-5 months <br />.

Safety Analysis

At the time the containment sump level and flow monitoring system was inoperable, the sumps' levels were below the hi-level setpoint

-(10 in. W.C.).

Their appropriate pumps are manually started only when their hi-level setpoint is reached to transfer water to the Floor Drain Tank.

Since there was no excessive leakage at that time, the inoperability of this system did not have any significant impact on the plant's safe operation and the health and safety of the public were not affected.

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Report Number 81-65 Page 2

Corrective Action

A work request was initiated immediately to restore the containment floor and equipment sump level instruments to operability when they failed.

The lifted wires on the breaker SkA-48 were reconnected.

Power was restored to the Waste Processing Panel which supplied power to the level transmitters. The level indicators were checked to be functioning properly and the containment sump level and flow monitoring system was declared operable on April' 23, 1981 at 0045 hours5.208333e-4 days <br />0.0125 hours <br />7.440476e-5 weeks <br />1.71225e-5 months <br />.

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