RE: Multiple Source Modeling Packages

[Glen.Vickers@ucm.com]

When it comes to performing calculations and comparing them to actual
measurements, the largest parts of uncertainty seems to be due to the
build-up methodology and the instrument response.  You will often measure
different quantities just because one instrument is a pulse counter and the
other is an ion chamber.  You will want to come up with a correction factor
or two, depending upon the accuracy desired.  

A good check would be to check previous shipment surveys to see if you can
calculated the same measured dose rate.  Once again, the modeled dose rate
is theoretical while the measured value is a compromise.  I have recently
performed a couple of such comparisons with the Megashield code from WMG and
it is quite easy to use and offers quite a few build-up options.  I believe
I have even seen a comparison of the code against Microshield and another
approximation method, perhaps call them at 914-736-7100 and ask for info.  I
would think an ion chamber would yield the best results with the
multiple-energy-group dose-response functions.  The few cases I've run so
far have yielded acceptable results, but I've really not performed enough
runs to provide a qualified opinion as to the true quality of the code.  

Megashield is also the dose-to-curie model used in the Radman computer code.
As I'm sure you know, the Radman code is essentially the standard for
characterizing waste in the nuclear power world.  The code also has models
for your standard shipping casks.  This is a real time saver.  


Sincerely,
Glen
glen.vickers@ucm.com

> -----Original Message-----
> From:	Lavera, Ron [SMTP:Ron.Lavera@nypa.gov]
> Sent:	Monday, February 14, 2000 12:06 PM
> To:	Multiple recipients of list
> Subject:	Multiple Source Modeling Packages
> 
> We are interested in finding out if anyone is using a PC based shielding
> calculation package that allows you to specify multiple sources of
> different
> values ( dose rate, curie content, specific activity, geometry or isotopic
> mix ).  We would like to do a better job of modeling expected dose rates
> on
> the outside of containers before we start preparing a shipment.
> 
> 
> Please provide the package name, a general idea about how well the package
> works and a contact for additional follow-up.
> 
> Thank you in advance for your time and consideration.
> 
> Ron LaVera
> Lavera.r@nypa.gov
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