§ 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 enrichment1(Wt%235 U present)	Specific activity
	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]