05000369/LER-1981-021, Forwards LER 81-021/03L-0.Detailed Event Analysis Encl

Forwards LER 81-021/03L-0.Detailed Event Analysis Encl

ML20032B329
Person / Time
Site:	McGuire
Issue date:	03/24/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20032B330	List: 05000369/LER-1981-021, Forwards LER 81-021/03L-0.Detailed Event Analysis Encl 05000369/LER-1981-021-03, /03L-0:on 810226,noble Gas Activity Monitor for Condenser Evacuation Sys EMF-33 Not Functioning.Caused by Excessive Amounts of Condensation in Sample Lines.Moisture Removed.Different Type of Moisture Separator to Be Used
References
NUDOCS 8111050438
Download: ML20032B329 (3)

LER-1981-021, Forwards LER 81-021/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3691981021R00 - NRC Website

text

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Mr. James P. O'Reilly, Director D.

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Docket No. 50-369 N

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Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report R0-369/81-21. This report concerns the operability of the noble gas activity monitor for the Condenser Evacuation System. This incident was considered to be of no significance with respe t to tSe health and safaty of the public.

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V y truly yours, l q O -4 (h. cA.0 b_ -

j William O. Parker, Jr.

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

20555 Palo Alto, California 94303 sp%

I 8111050438 810324 PDRADOCKOSOOOg S

DUKE POWER COMPANY MCGUIRE NUCLEAR STATION Repcrt humber: R0-369/81-21 Report Date: March 10, 1981 Occurrence Date: February 26, 1981, 1033 Hours Facility: McGuire Unit 1, Cornelius, North Carolina Identification of Occurrence:

The noble gas activity monitor for the Condenser Evacuation System, EMF-33, was discovered to be inoperable.

Condition Prior to Occurrence: Mode 5, Cold Shutdown Description of Occurrence:

On February 26, 1981 at 1033 hours0.012 days <br />0.287 hours <br />0.00171 weeks <br />3.930565e-4 months <br />, Operations was notified that EMF-33 was not functioning. Technical Specification 3.3.3.9 requires EMF-33 to be operable at all times. Consequently, this failure resulted in a degraded mode of operation, and necessitated implementation of action statement No. 37 of Table 3.3-13.

Apparent Cause of Occurrence:

The inoperability of the air pump and the alarm switch was directly related to excessive Q )unts of condensation in the sample lines. A moisture trap is cur-rently incorporated in the line but it has been confirmed that is is the wrong type of trap and it is not effective when used in a vacuum system.

Analysis of Occurrence:

On February 26, 1981 at 1030 hours0.0119 days <br />0.286 hours <br />0.0017 weeks <br />3.91915e-4 months <br />, Duke personael went to EMF-33 for the purpose of evaluating some means of reducing excess moisture in the system. This monitor had a history of failures which resulted from the deleterious effects of ccndensa-tion in the sample line.

It was determined, based on pump noise and readings on the vacuum and flow gauges, that the pump was not operating properly.

Control room personnel were notified that the pump was going to be turned off.

There was no indication in the control room, before or af ter the pump was turned off, that the system was malfunctioning. Closer examination revealed large amounts of water in the pump and in the alarm switch. Health Physics submitted a work request to have the system repaired.

I&E technicians repaired the system and again removed excessive moisture from the sample lines.

The system was declared operable at 1810 hours0.0209 days <br />0.503 hours <br />0.00299 weeks <br />6.88705e-4 months <br /> on February 27, 1981.

The health and safety of the public were not affected by this loss of operability because no radiation, above natural background exists in any of the plant's systems at this time.

Corrective Action

Drawings of proposed resolutions have been made and tentatively approved by cognizant Duke personnel.

The rolution involves removing the present moisture separator and associated tubing and replacing it with a vortex-type moisture separator and incorporating a loop seal.

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