Re:MISC./Radsafe: localized air modeling

[Elizabeth Algutifan <elizabeth_algutifan@wssrap-host.wssrap.com>]

David, how close is close? If this is a ground level source, I'm assuming 10's
of meters. If it is a ground level source, can it be elevated? What's the nature
of your source - internal hazard, external hazard, or both? I did this type of
project a couple of years ago for our site to verify that our perimeter air
monitors were properly sited. In that particular situation, we were dealing with
radioactive airborne particulates emitted from ground-level diffuse sources
(earth moving). I used ISC3 which is a Gaussian plume model with all standard
disclaimers regarding modeling close-in receptor locations. It spit out results
that tended to be extremely conservative (like a factor of 1,000 greater than
what we actually saw through monitoring). Those receptors tended to be on the
order of 50-100 meters from the source. 

I guess you know what happens when you try to do Gaussian plume modeling right
up next to a source - it blows up in your face. Our normal method for placing
portable work area monitors is not very scientific; basically they are sited in
the forecasted predominant downwind direction for that work day at a distance
where the workers are likely to be located. I guess you could do "box modeling"
if someone is requesting that you do a full-blown modeling study. 

Give me a call if you'd like to discuss this further. I'd be interested to hear
the details of your task. 

Elizabeth Algutifan, CHP
Weldon Spring Site 
St. Charles, MO 
(636) 441-8086, ext. 3514
Elizabeth_Algutifan@wssrap-host.wssrap.com

____________________Reply Separator____________________
Subject:    MISC./Radsafe:  localized air modeling 
Author: <radsafe@romulus.ehs.uiuc.edu>
Date:       02/03/2000 2:18 PM

     People,
     
     'am looking for method by which to do some air modeling CLOSE to a 
     radiological point source to determine areas of maximum potential 
     exposure.  We're seeking to pick some 'best' points for performing 
     investigative air sampling, hopefully to show compliance with the DOE 
     requirement to perform personnel monitoring in locations where 
     individuals could receive 100 mrem in a year.
     
     Anyone know of any modeling programs that would be good for this 
     purpose?
     
     Thanks in advance!
     
     --David Levy
     Fernald, Ohio

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