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Re[2]: MISC./Radsafe: localized air modeling



     Elizabeth,
     
     I probably will give you a call.  
     
     I am responding to the bulletin board in case everyone's interested in 
     further detail:  the situation you described below is pretty much the 
     same as ours (diffuse ground-level sources due to earth moving).  I 
     will look into that ISC3.
     
     Thanks!
     
     --Dave


______________________________ Reply Separator _________________________________
Subject: Re:MISC./Radsafe:  localized air modeling 
Author:  <radsafe@romulus.ehs.uiuc.edu> at FE-INTERNET
Date:    02/03/2000 3:20 PM


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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information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html