§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]