RE: Apparent Illegal Shipment

["Rick Orthen" <rorthen@cecinc.com>]

Syd,



Consider a typical thorium-228, -230, -232 mix with a total specific

activity of around 780 pCi/g, well below the "old" definition of DOT

Class 7 radioactive material (2,000 pCi/g).  Under HM-230, 49CFR173.436

gives an equivalent total exempt concentration of 324 pCi/g (27+27+270),

making this material Class 7.  [There is a new exemption at

173.401(b)(4) for natural materials "which are not intended to be

processed for use . . . provided the activity concentration  .  . . does

not exceed 10 times" the exempt concentration.  If this case could be

made, the material would be exempt.  However, like most exemptions

(particularly those involving waste materials), it is subject to

interpretation that may not benefit the shipper.]



The new exempt concentration for Th-228 includes contributions from

secular equilibrium progeny (Ra-224 through Th-208).



BTW--In first post, I meant to type "Class 9", not "non-Class 9".



Rick Orthen



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