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In
the USA, there is a regulatory provision (10 CFR 40.51 & 40.53) to transfer
to unlicensed persons material containing less than 0.05% (by weight) of source
material, including Th-232. However, a potential dose assessment is
necessary to demonstrate compliance with the 1 mSv/year public TEDE
constraint. Note that 0.05% natural thorium is 4.29 Bq/g Th-228 and
Th-232. For a specific application involving unconsolidated thoriated dust
and thoriated slag, see:
There appears to be conforming guidance available from the
European Commission (EC) in "Radiation Protection 89" (metals recycling)
published in Luxembourg in 1998. I am not
familiar with the recycling market in the US for aerospace alloys, but
companies such as Kaiser Aluminum and Fansteel maintain such product
lines.
Rick Orthen
Earth Sciences Consultants,
Inc.
Export,
PA |