Re: Natural Uranium and Thorium at DOT Exempt Levels

[LIPTONW@dteenergy.com]

Although this provision of the regulations does not strictly apply to 
determining whether you have "radioactive material" for purposes of 
transportation, 49CFR173.433(c) can probably be used. 
 
" ... a single radioactive decay chain in which the radionuclides are
present 
in their naturally-occurring proportions, and in which no daughter nuclide
has 
a half life either longer than 10 days or longer than that of the parent 
nuclide, will be considered as a single radionuclide ... Otherwise, the
parent 
and daughter nuclides will be considered as a mixture of different
nuclides." 
 
I also recommend consulting NUREG-1608, "Categorizing and Transporting Low 
Specific Activity Materials and Surface Contaminated Objects."  See section 
3.1.2, on page 3-2:  "Is there a contamination level below which an object 
does not need to be categorized as an SCO or as radioactive material,
n.o.s.?" 
 This "guidance" states that if the contamination levels on an otherwise 
nonradioactive object are less than 0.4 Bq/cm2 beta-gamma and 0.04 Bq/cm2 
alpha, than the object may be considered as nonradioactive for purposes of 
transportation.  This may be a big help in shipping slightly contaminated 
equipment which cannot be free released. (Disclaimer - Be sure to read this 
carefully and in context before actually using this provision for shipping 
something.) 
 
The opinions expressed are strictly mine. 
It's not about dose, it's about trust. 
 
Bill Lipton 
liptonw@dteenergy.com 
 
 
You wrote: 
 
>definition for Radioactive Material specified in 49CFR173.403 should the = 
>daughters in equilibrium be added to calculate specific activity?  = 
>173.434 is a chart of activity-mass relationships for U and Th which = 
>doesn't include the daughters. 
 
>Thanks, 
 
>Lori Glander RRPT 
>lglander@scientech.com
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