49 CFR § 173.434 - Activity-mass relationships for uranium and natural thorium.

§ 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
TBq/gram Grams/Tbq Ci/gram Grams/Ci
0.45 (depleted) 1.9 × 10−8 5.4 × 10 7 5.0 × 10−7 2.0 × 10 6
0.72 (natural) 2.6 × 10−8 3.8 × 10 7 7.1 × 10−7 1.4 × 10 6
1.0 2.8 × 10−8 3.6 × 10 7 7.6 × 10−7 1.3 × 10 6
1.5 3.7 × 10−8 2.7 × 10 7 1.0 × 10−6 1.0 × 10 6
5.0 1.0 × 10−7 1.0 × 10 7 2.7 × 10−6 3.7 × 10 5
10.0 1.8 × 10−7 5.6 × 10 6 4.8 × 10−6 2.1 × 10 5
20.0 3.7 × 10−7 2.7 × 10 6 1.0 × 10−5 1.0 × 10 5
35.0 7.4 × 10−7 1.4 × 10 6 2.0 × 10−5 5.0 × 10 4
50.0 9.3 × 10−7 1.1 × 10 6 2.5 × 10−5 4.0 × 10 4
90.0 2.1 × 10−6 4.7 × 10 5 5.8 × 10−5 1.7 × 10 4
93.0 2.6 × 10−6 3.9 × 10 5 7.0 × 10−5 1.4 × 10 4
95.0 3.4 × 10−6 3.0 × 10 5 9.1 × 10−5 1.1 × 10 4
Natural thorium 8.1 × 10−9 1.2 × 10 8 2.2 × 10−7 4.6 × 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]