re: Liquid Effluent Monitoring

[JHageman@swri.edu]

Leon, Electropolishing may not help to prevent contamination by ionic or 
microscopic metal particles.

Here at Southwest Research Institute, we have plastic or epoxy coated a 
sample chamber to prevent contamination buildup and to facilitate 
decontamination. I seem to recall that there is a teflon type spray on 
coating, that may need to be applied by a professional coatings company. You 
may want to look into making the entire chamber out of plastic.
 
Also, if you are stuck with a metal counting chamber you may want to try 
placing a small DC voltage on the chamber so that it does not attract ionic 
metal particles. Make sure you have the voltage hooked up right, and be 
prepared for some of the chamber's metal to be sacrificially lost to the 
water.

Call if you have any questions, at 210-522-2633 or email to jph@swri.edu.

Hope you find a solution, John P. Hageman, RSO.

- - - - - - - - - - - - - - Original Message - - - - - - - - - - - - - -
The Big Rock Point Restoration Project is experiencing a problem making 
liquid
effluent releases now that we are in decommissioning.  Some of you may be 
able
to offer some words of advice to help us out.  Now that we have very little
dilution flow for making liquid effluent discharges (no circ water flow), our
liquid effluent discharge rates have been reduced by a factor of 10.

That poses a problem with monitor chamber contamination during discharges.  
The
reduced discharge rate and flow through the liquid effluent monitor has 
resulted
in an increased contamination rate for the monitor chamber.  We typically 
start
a liquid discharge with a monitor background of 4,000 cpm and a calculated 
alarm
setpoint of 20,000 cpm.  Before we are able to discharge the entire batch 
tank,
the monitor background will build up to 10,000 cpm where we will have to halt
the discharge and decon the monitor chamber due the number of spurious alarms 
we
receive.  This sometimes requires us to calculate a new alarm setpoint due to 
a
different background than we originally started with before we can restart 
the
discharge.

Our question is:  Have you found any effective methods to prevent or reduce 
the
buildup of contamination in your liquid effluent monitor's chamber?  We are 
even
considering sending it off to be electropolished to reduce buildup.

Leon E. Brown, CHP
Sr. Consultant
Big Rock Point Restoration Project
(231) 547-8419
lebrown@cmsenergy.com


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