ML20059M420

Special Rept:On 900908,reactor Coolant Radiation Level Monitor Inoperable Due to Low Flow Through Monitor.Caused by Sample Tube Replaced W/Incorrect Gauge Tube.Tube Replaced. Monitor Will Be Returned to Svc Prior to 900929

ML20059M420
Person / Time
Site:	Catawba
Issue date:	09/24/1990
From:	Tucker H DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9010040162
Download: ML20059M420 (2)

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' (TN)3734531 l DUKE POWER September 24, 1990 U. S. Nuclear Regulatory C a ission Attention: Docm:$ ?.?ntrol Desk Washington, DC 20ab5

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Subject:

Catawba Nuclear Station  :

Docket No. 50-414 Special Report Gentlemen:

Pursuant-to Technical. Specifications 6.9.2 and 3.3.3.6, please find attached a Special Report concerning the inoperability of the Reactor Coolant Radiation' :1 Level Monitor (2 EMF 48).

Very truly you s, i H. . Tucker  !

MHM/td -i I

Attachment cc: Mr. S. D. Ebneter Regional Administrator, Region II' U. S. Nuclear Regulatory Commission 101 Marietta Street, NW, Suite 2900 Atlanta, GA 30323 Dr.'K. N. Jabbour Office of Nuclear Regulation U. S. Nuclear . Regulatory. Commission ,

One White Flint North  !

Washington, DC 20555 '

? . W. T,' Orders.

NRC' Resident Inspector Catawba Nuclear Station  !

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.j 9010040162 900924  !

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i REACTOR COOLANT RADIATION LEVEL MONITOR (2 EMF 48) INOPERABLE ~

The Reactor Coolant Radiation Level Monitor became inoperable on September 8, 1990 due to a low flow through the monitor.

A Work Request was written to investigate and repair 2 EMF 48. First the flow setpoints for the instrument were verified to be correct. 2 EMF 48 was then flushed in an attempt to clear any crud buildup in the sample tube. The flush did not clear the blockage. The position of downstream valves was then.

verified to ensure that they were not the source ofathe reduced flow. While-r eviewing a Work Request performed on September 6,1990,. Duke personnel ictntified that the sample tube had been.roplaced with the incorrect gauge tube. The sample tube was replaced with a 20 gauge tube as recommended by the vendor.

While attempting to return 2 EMF 48 to service, a poor correlation between the output module and reactor coolant sample was identified. This is usually due '

to contamination of the sample tube, but since the sample tube.was new, '

trouble shooting of the output module and detector was determined to be necessary.

Unit 2 left the required modes for 2 EMF 48 (Modes 1-3) on September 14, 1990.

Trouble shooting is ongoing, with plans to return 2 EMF 48 to service prior to the end of the current Unit 2 outage scheduled.to end on September 29, 1990.

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