05000369/LER-1981-026, Forwards LER 81-026/03L-0.Detailed Event Analysis Encl

Forwards LER 81-026/03L-0.Detailed Event Analysis Encl

ML20032B284
Person / Time
Site:	McGuire
Issue date:	04/03/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20032B285	List: 05000369/LER-1981-026, Forwards LER 81-026/03L-0.Detailed Event Analysis Encl 05000369/LER-1981-026-03, /03L-0:on 810305,EMF Sys Panel Alarm in Control Room Indicated Malfunction of EMF-43A.Alarm Could Not Be Cleared & Control Room Outside Air Intake Gaseous Activity Monitor Inoperable.Caused by Broken Bnc Jack
References
NUDOCS 8111050392
Download: ML20032B284 (3)

LER-1981-026, Forwards LER 81-026/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3691981026R00 - NRC Website

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DUKE Powcu COMPANY Pow en 13c wswo 422 SocTu Cnicacia STurzT, CnAHwTTE, N. C. aa24a SI-osy'-ssy

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April 3, 1981 WC t Patsiotwv TttEPacNC: Anta 704 Straea Pacouctio%

3 7 3-40 P L Mr. James P. O'Reilly, Director

& (II[/f U. S. Nuclear Regulatory Commission

/f Region II 8

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101 Marietta Street, Suite 3100 h, J h,)

Atlanta, Georgia 30303 NOVO 319815 u.s. g y ross,' j Ts/'

fjl Re: McGuire Nuclear Station Unit 1 hfg If Docket No. 50-369

Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report R0-369/81-26. This report concerns intaerable gaseous activity monitor EMF-43A. This incident was con-sidered to ' a of no significance with respect to the health and safety of the public.

1 Very truly yours, 7

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,Ouan-di.

'c u William O. Parker, J,.

I RWO:scs Attachment cc: Director Mr. Bill Lavallee Office of Management and Program Analysis Nuclear Safety Analysis Center U. S. Nuclear Regulatory Commission P. O. Box 10412 Washington, D. C.

20555 Palo Alto, California 94303 i

SI 8111050392 810403 PDR ADOCK 05000369 S

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i DUKE POWER COMPANY MCGUIRE NUCLEAR STATION INCIDENT REPORT Report Number: R0-369/81-26 Report Date: March 13, 1981 Occurrence Date: Match 5, 1981, 1530 Hours Facility: McGuire Unit 1, Cornelius, North Carolina Identification of Occurrence:

1-DT-43A, One of the Control Room Outside Air Intake Gaseous Activity Monitors, Was Declared Inoperable Condition Prior to occurrence: Mode 5, Cold Shutdown Description of Occurrence:

On March 5, 1981, at 1530 hours0.0177 days <br />0.425 hours <br />0.00253 weeks <br />5.82165e-4 months <br />, the EMF system panel alarm in the Control Room indicated a malfunction of 1-DE-43A; the alarm could not be cleared.

1-DT-43A was, therefore, declared inoperable. This constituted a degraded mode of operation parsuant to Technical Specification 3.3.3.1 and required implementation of Action Statement No. 27 as stipulated in Table 3.3-6.

Apparent Cause of Occurrence:

The apparent cause of this occurrence was a broken BNC jack located in the back of the E!' cabinet. The jack is a common electrical coupling that provides a secure twist-lock connection for electrical cables. The center portion of the jack was not firmly afixed to its base. Therefore, the twisting movement of attaching the electrical cable degraded this connection to the point of eventually allowing an electrical short to occur.

I&E personnel have discovered a number of similar defects in other equipment through-out the plant.

It is gen =:ially felt that the defects were the result sf improper handling during installation or testing rather than improper equipment design or construction.

Analysis of Occurrence:

At 1530 hours0.0177 days <br />0.425 hours <br />0.00253 weeks <br />5.82165e-4 months <br /> on March 5, 1981, Operations' personnel in the Control Room received an audible DT system panel alarm. The shift supervisor investigated the signal and discovered that the green, " operating" light for DE-43A was not on.

He pressed the reset button to clear the alarm but the light remained off. The system was, therefore, declared inoperable and work request number 102011-OPS was written to have the EMF repaired. Valves 1-VD-1, -2,

- 2,

- 4, the outside

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air intake isolation valves, were closed to comply with Technical Specification

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Action Statement No. 27 of Table 3.3-6.

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I&E technicians examined the system and ascertained that the cause of the alarm was a broken BNC jack located in the back o ' the DiF cabinet. The jack was replaced and the system was checked for calibration and operability.

The system was turned back over to Operations at 2230 hours0.0258 days <br />0.619 hours <br />0.00369 weeks <br />8.48515e-4 months <br /> on March 9, 1981.

Safety Evaluation:

The Control Room ventilation monitor is provided to continually monitor the gaseous activity levels within the Control Room and automatically closes the ventilation intake or. a high radiation signal. This occurrence indicated an equipment malfunction which caused the instrument to go off-scale on the low end of the instrument's range.

It had no effect on the health and safety of the public.

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