CFR

CFR

173.434—Activity-mass relationships for uranium and natural thorium.

The table of activity-mass relationships for uranium and natural thorium are as follows:

Thorium and uranium enrichment 1(Wt% 235 U present)	Specific activity
Thorium and uranium enrichment 1(Wt% 235 U present)	TBq/gram	Grams/Tbq	Ci/gram	Grams/Ci
0.45 (depleted)	1.9×10−8	5.4×107	5.0×10−7	2.0×106
0.72 (natural)	2.6×10−8	3.8×107	7.1×10−7	1.4×106
1.0	2.8×10−8	3.6×107	7.6×10−7	1.3×106
1.5	3.7×10−8	2.7×107	1.0×10−6	1.0×106
5.0	1.0×10−7	1.0×107	2.7×10−6	3.7×105
10.0	1.8×10−7	5.6×106	4.8×10−6	2.1×105
20.0	3.7×10−7	2.7×106	1.0×10−5	1.0×105
35.0	7.4×10−7	1.4×106	2.0×10−5	5.0×104
50.0	9.3×10−7	1.1×106	2.5×10−5	4.0×104
90.0	2.1×10−6	4.7×105	5.8×10−5	1.7×104
93.0	2.6×10−6	3.9×105	7.0×10−5	1.4×104
95.0	3.4×10−6	3.0×105	9.1×10−5	1.1×104
Natural thorium	8.1×10−9	1.2×108	2.2×10−7	4.6×106
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]

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