Re: Question on Specific Activity

[Tad Blanchard <Tad.M.Blanchard.1@gsfc.nasa.gov>]

I understand this to be as Keith stated from his class of instruction.  You
can't use the "package" in the calculation of specific activity.  The key
words are.. "uniformly distributed."


>Jim Williams responded:
>
>	For DOT (not NRC, disposal site classifications, etc.) purposes, you
>avergage over the gross weight of the "package". <SNIP>
>-----------------
>This is interesting because it is not what I gathered from the training
>that I received recently.  I had the same basic question, and if I remember
>correctly, the expert opinion of the instructors was that you should use a
>great deal of caution when determining the specific activity.  No mention
>of taking credit for the weight of the package was mentioned - and in fact,
>the prevailing wisdom was that even a single solid item that had a small
>spot of radioactivity may not be allowable for averaging purposes.  The
>reasoning was that the activity needed to be relatively evenly distributed
>in the material.  So for instance if you have a 200 pound piece of steel
>plate with a 1" hot spot on it, you better be careful about trying to
>average the activity over the entire piece.  So a button source had to be
>considered a single entity, and if it was boxed in a 100 lb crate, that
>didn't matter.
>
>I know that Jim is an expert shipper, so this is confusing.  Does anyone
>have any specific regulatory guidance from DOT that answers this question -
>some kind of position statement that could be referenced.
>
>
>Keith Welch
>Thomas Jefferson National Accelerator Facility
>Newport News VA
>welch@cebaf.gov
>Ph: (757)269-7212
>FAX:(757)269-5048
>
>
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Tad  Blanchard            /__ \ /___\   NASA-Goddard Space Flight Center
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