Re: Question on Specific Activity

[Jim Williams <NARM@worldnet.att.net>]

Tim Paul wrote:
> 
> Hello,
> 
> I have a question regarding the definition of Radioacive material in 49 CFR
> Part 173.403.  If the specific activity is greater than 2 nCi/g, then it is
> radioactive.
> 
> When determining specific activity, what can you average this over?  Is it
> just the source/sources inside or the entire contents and container?

	For DOT (not NRC, disposal site classifications, etc.) purposes, you
avergage over the gross weight of the "package". In most cases, unless
you are using an "overpack", this means the same drum, box, etc. that
you put the markings and labelings on. I have seen this question asked
many times, but the answer is always the same.

	Assume that you had a 100 uCi check source. You place the the check
source in cardboard box and the gross weight is now 2000 grams. In this
case, the specific activity of the "package" is 50 nCi/gram, thus it is
radioactive per DOT.

	If the same check source were placed in a metal drum and the gross
weight was 100,000 grams (~200 pounds) the package would not be
radioactive per DOT. Classification as radioactive in this case would
violate 49 CFR 171.2(f)(2).

	It is common for radioactive waste disposal and processing facilities
to receive radwaste that is not a hazardous material per DOT. In fact, I
once shipped a non-DOT regulated package that required disposal as Class
C waste!

	This only applies to the DOT clasification. In most, but not all, other
situations you do not include the weight of the empty packaging(s).

Jim Williams
NARM@Worldnet.att.net