05000369/LER-1981-100, Forwards LER 81-100/03L-0.Detailed Event Analysis Encl

Forwards LER 81-100/03L-0.Detailed Event Analysis Encl

ML20009E516
Person / Time
Site:	McGuire
Issue date:	07/16/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20009E517	List: 05000369/LER-1981-100, Forwards LER 81-100/03L-0.Detailed Event Analysis Encl 05000369/LER-1981-100-03, /03L-0:on 810616,in Mode 5,curve on Lower Wind Direction Monitoring Instrument Recorder Strip Chart Discovered Unrealistic.Caused by Failure of Wind Sensor Shaft Bearing.Sensor Replaced
References
NUDOCS 8107280274
Download: ML20009E516 (3)

LER-1981-100, Forwards LER 81-100/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3691981100R00 - NRC Website

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July 16, 1981 an-4ess tn Mr. James P. O'Reilly, Director Q~ Q;g[, f [

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Region II 101 Marietta Street, Suite 3100 l-Atlanta, Georgia 30303

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

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Dear Mr. O'Reilly:

2 Please find attached Reportable Occurrence Report R0-369/81-100.

This report concerns Technical Specification 3.3.3.4; "the meteorological monitoring in-strumentation channels shown in Table 3.3-8 shall be operable". This incident was considered to be of no significance with respect to the health and safety of the public.

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PBN:pw Attachment cc: Director Mr. Bill Lavallee Office of Management & Program Analysis Nuclear Safety Analysis Center U.S. Nuclear Regulatory Commission Post Office Box 10412 Washington, D. C.

20555 Palo Alto, CA 94303 Ms. M. J. Graham Resident Inspector - NRC McGuire Nuclear Station

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e McGUIRE NUCLEAR STATION REPORTABLE OCCURRENCE Report Number:

81-100 Report Date:

July 16, 1981 Occurrence Date: June 16, 1981 Facility:

McGuire Unit 1 Cornelius, N. C.

Identification of Occurrence: Meteorological Instrumentation for wind direction was declared inoperable.

Condition Prior to Occurrence: Mode 5, Cold Shutdown Description of Occurrence: On June 16, 1981 et 1110 hours0.0128 days <br />0.308 hours <br />0.00184 weeks <br />4.22355e-4 months <br />, the lower wind di-rection monitoring instrument was found to be working improper 3y.

The data taken from the Esterline-Angus (E.A.) Strip Chart Recorder showed abrupt wind direction changes instead of the expected gradual changes.

Control Room per-sonnel declared this meteorological monitoring instrument inoperable and this incident was therefore reportable pursuant to Technical Specification 3.3.3.4.

Apparent Cause of Occurrence:

The wind direction sensor (Model 1022, Meteoro-logical Research Inc.) is provided with a shaft which has a vane counted on one end and a ganged two-seenion potentiometer (20K ohm per section) on the other.

The shaft's bearing, which allows the vane and the potentiometers to rotate freely in any direction, failed.

This caused the shaft to drag; hence the measured potentiometer resistances were not representative of the true wind direction.

Analysis of Occurrenec:

On June 16, 1981 at 0930 hours0.0108 days <br />0.258 hours <br />0.00154 weeks <br />3.53865e-4 months <br />, the strip chart on the E.A. Recorder for the lower wind d;tection monitoring instrument was changed.

It was noticed that the curve had an unrealistic shape based (n previous ex-perience.

This was reported and a work request initiated to troubleshoot the instrament.

It w;s found that the vane on the lower wind direction sensor would not ro t' ate freely due to a bad bearing. This was reported in the Control Room and the instrument was declared inoperable (1110 hours0.0128 days <br />0.308 hours <br />0.00184 weeks <br />4.22355e-4 months <br />) per Technical Speci-fication 3.3.3.4.

The sensor was replaced with a new one and it wa; checked for proper operation per procedure, "MRI Wind Direction Loop Check Semi-Annual Calibration Procedure".

The lower wind direction monitoring instrument was declared operable at 1406 hours0.0163 days <br />0.391 hours <br />0.00232 weeks <br />5.34983e-4 months <br /> that same day.

Safety Analysis

The Station Meteorological Monitoring System provides suitable on-site capability to estimate potential radiation doses as a result of routine or accidental releases of radioactive materials to the atmospher.

This is accomplished by measuring and reporting meteorological parameters such as wind speed, wind direction, AT, ambient temperature and dew point.

At the time the lower wind direction monitoring instrument was inoperable, there were no radio-active gasecus waste releases made and the upper wind direction monitoring in-strument (elevation 886 ft.) was operable.

Therefore, the health and safety of the public and the safe operation of the plant were not affected by this incident.

Report Number 81-100 Page 2

Corrective Action

A work request was initiated to troubleshoot the failed equipment.

The old sensor (S/N 575) was taken out of service and replaced with a new one (S/N 771).

The equipment was tested (loop checked) for pro-per operation and was seclared operable on June 16, 1981 at 1406 hours0.0163 days <br />0.391 hours <br />0.00232 weeks <br />5.34983e-4 months <br />.

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