Liquid Effluent Monitoring

["Leon E Brown" <lebrown@cmsenergy.com>]

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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