The table of activity-mass relationships for uranium and natural thorium are as follows: ----------------------------------------------------------------------------------------------------------------
Specific activity
Thorium and uranium enrichment \1\(Wt% \235\ U present) ---------------------------------------------------
TBq/gram Grams/Tbq Ci/gram Grams/Ci----------------------------------------------------------------------------------------------------------------0.45 (depleted)............................................. 1.9 x 10-8 5.4 x 10\7\ 5.0 x 10-7 2.0 x 10\6\0.72 (natural).............................................. 2.6 x 10-8 3.8 x 10\7\ 7.1 x 10-7 1.4 x 10\6\1.0......................................................... 2.8 x 10-8 3.6 x 10\7\ 7.6 x 10-7 1.3 x 10\6\1.5......................................................... 3.7 x 10-8 2.7 x 10\7\ 1.0 x 10-6 1.0 x 10\6\5.0......................................................... 1.0 x 10-7 1.0 x 10\7\ 2.7 x 10-6 3.7 x 10\5\10.0........................................................ 1.8 x 10-7 5.6 x 10\6\ 4.8 x 10-6 2.1 x 10\5\20.0........................................................ 3.7 x 10-7 2.7 x 10\6\ 1.0 x 10-5 1.0 x 10\5\35.0........................................................ 7.4 x 10-7 1.4 x 10\6\ 2.0 x 10-5 5.0 x 10\4\50.0........................................................ 9.3 x 10-7 1.1 x 10\6\ 2.5 x 10-5 4.0 x 10\4\90.0........................................................ 2.1 x 10-6 4.7 x 10\5\ 5.8 x 10-5 1.7 x 10\4\93.0........................................................ 2.6 x 10-6 3.9 x 10\5\ 7.0 x 10-5 1.4 x 10\4\95.0........................................................ 3.4 x 10-6 3.0 x 10\5\ 9.1 x 10-5 1.1 x 10\4\Natural thorium............................................. 8.1 x 10-9 1.2 x 10\8\ 2.2 x 10-7 4.6 x 10\6\----------------------------------------------------------------------------------------------------------------\1\ The figures for uranium include representative values for the activity of uranium-234 which is concentrated
during the enrichment process. The activity for thorium includes the equilibrium concentration of thorium-228. [Amdt. 173-244, 60 FR 50307, Sept. 28, 1995, as amended by 63 FR 52849, Oct. 1, 1998]