Re: Radon Determination

["Brian Rees" <brees@lanl.gov>]

Orville,

A portable alpha spec will reveal the higher energy alphas from Rn progeny.
Some sort of conversion could be established between the observed count
rate, and the count rate of alphas > 4.8 Mev to eliminate at least some of
your "false" alarms.

I'm not familiar enough with UF6 and HF to comment on other aspects.

Operating the PCM-2s in Preset all with a longer count time may also
eliminate some alarms because the confidence level is effectively increased.
(Jeff Sawyer at Eberline can help 505-471-3232 ext 237).  We reduced false
alarms here by about 50% this winter by increasing our count time from 12 to
16 sec.


Brian Rees
Los Alamos National Laboratory
Plutonium Facility Health Physics Operations
brees@lanl.gov

-----Original Message-----
From: Orville Cypret 441-6411 <CYPRETOW@lmus.com>
To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
Date: Wednesday, July 08, 1998 12:04 PM
Subject: Radon Determination


>I'm trying to find a simple method for discriminating between environmental
Rn
>contamination and uranium + daughters in the field.  We use Berthold hand &
foot
>monitors, and Eberline PCM-1B and PCM-2 half-body monitors and they
frequently
>alarm due to Rn.  Raising the alarm setpoint isn't an option.  We have a
large
>inventory of gaseous, liquid, and solid uranium hexafluoride here so the
>presence of Rn is not unexpected.  Generally, we don't believe the source
of the
>Rn is the enrichment process system since we do not detect HF when we're
having
>Rn problems and it doesn't seem reasonable for the Rn to leak out of the
process
>piping without UF6 also leaking out and forming HF.  The environment is
>typically around 100 degrees F (or more) and resolving an alarm may take
30-60
>minutes.  If a person is experiencing heat stress, we don't want to delay
them
>at the monitoring point any longer than is absolutely necessary.
>
>I need to teach our technicians how to discriminate between Rn and uranium
+
>(short lived) daughters since our response for the two is different.
Although
>this sounds like it ought to have a simple answer, in a uranium enrichment
plant
>it's hard to do.  We have a wide selection of Ludlum and Bicron survey
>instruments available to the technicians for field measurements.  Any
>suggestions would be appreciated.
>
>Orville Cypret
>Paducah Gaseous Diffusion Plant
>Lockheed Martin Utility Services
>cypretow@lmus.com
>502/441-6173
>