05000369/LER-1981-013, Forwards LER 81-013/03L-0.Detailed Event Analysis Encl

Forwards LER 81-013/03L-0.Detailed Event Analysis Encl

ML20032B534
Person / Time
Site:	McGuire
Issue date:	03/11/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20032B535	List: 05000369/LER-1981-013, Forwards LER 81-013/03L-0.Detailed Event Analysis Encl 05000369/LER-1981-013-03, /03L-0:on 810212,radiation Detectors EMF 33,35,36, 37,38,39 & 40 Were Declared Inoperable Due to Loss of Sample Flows.Caused by Individual Nonrelated Failures of Each Emf. Repairs Performed & EMFs Declared Operable
References
NUDOCS 8111050641
Download: ML20032B534 (3)

LER-1981-013, Forwards LER 81-013/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3691981013R00 - NRC Website

text

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

Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report R0-369/81-13. This report concerns the operability of certain radiation detectors.

This incident was considered to be of no significance with respect to the health and safety of the public.

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William O. Parker, Jr.

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.

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MCGUIRE NUCLEAR STATION INCIDENT REPORT Report Number: R0-50-369/81-13 Report Date:

February 24, 1981 Occurrence Date: February 12, 1981 Facility: McGuire Unit 1, Cornelius, North Carolina Identification of Occurrence:

Radiation Detectors DE 33 (Condenser St2am Air Ejector), DiF's 35, 36, 37 (Unit Vent Particulate / Gas / Iodine) and DE's 38, 39, 40 (Centainment Particulate /

Gas / Iodine) were declared inoperable due to loss of sample flows.

Condition Prior to Occurrence: Mode 6, Initial Fuel Loading Description of Occurrence:

The monitoring function of DIF's 33 and 39 was, by design backed up by DiF 36; however, the simultaneous inoperabilit.y of DiF 39 and DT 36 resulted in less than the minimum number of channels necessary for operation.

DE 33 is required to be operable at all times. These events constituted a degraded mode of operation as stipulated in Technical Specifications 3.3.3.9 and required going to the appropriate action statement as shown in Table 3.3-13.

Apparent Cause of Occurrence-The cause of the occurrence was actually multifaceted due to the individual, non-related failures of each of the DE's.

The incident was made significant due to the concurrent failures of interdependent monitors, i.e., EMF's 36 and 39.

The individual failures of the monitors were as follows:

1.

DiF incorrect vacuum setting; water in vacuum switch and associated tubing.

2.

DE 35, 36, and 37 - clogged filter; incorrect vacuum adjustn.e.it.

3.

DIF 38, 39, and 40 - vacuum pump motor burned up.

Analysis of Occurrence:

Containment On February 8,1981, DiF's 38, 39 and 40 were declared inoperable.

purge samples were taken every eight (8) hours as stipulated in Action Statement No. 37 of Technical Specifications Table 3.3-13.

These samples were obtained in the upper containment rather than at the DIF's in order to prevent any further false reactor building evacuation alarms. This, in itself, was not a reportable incident.

On February 11, 1981 at 2350 hours0.0272 days <br />0.653 hours <br />0.00389 weeks <br />8.94175e-4 months <br />, Operations notified Health Physics of a loss of flow alarm on EMF's 35, 36, and 37; two Health Physics technicians were dis-patched to change the filters.

This failed to alleviate the problem. At 0300 on February 12, 1981, EMF's 35, 36, and 37 were declared inoperable.

At 0200, EMF's 38, 39, and 40 were declared operable; at 0600 hours0.00694 days <br />0.167 hours <br />9.920635e-4 weeks <br />2.283e-4 months <br />, EMF's 38, 39, and 40 again alarmed due to loss of flow. The charcoal and particulate filters were changed; there was still no improvement. Monitors EMF 38, 39, and 40 were declared inoperable at 0630. Moreover, EMF-33 was declared inoperable at 1030 hours0.0119 days <br />0.286 hours <br />0.0017 weeks <br />3.91915e-4 months <br /> that same day.

Health Physics was instructed to obtain and analyze appropriate grab sampics as per Table 3.3-13.

The results of these analyses demonstrated that no radio-activity above natural background was present. These results confirmed that the safety and health of the public were not affected.

Corrective Action

Work requests were initiated to investigate and repair the EMF;s.

1.

101731 - OPS - E4F's 38, 39, and 40 2.

101734 - OPS - EMF's 35, 36, and 37 3.

101741 - OPS - EMF 33 Unit vent grab samples were taken every eight (8) hours until the EMF's were declared operable.

Instrument and Electrical technicians performed the necessary repairs and the EMF's were declared operable on February 12, 1981.

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