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Appendix E to 10 CFR Part 20--Nationally Tracked Source Thresholds
Appendix E to Part 20--Nationally Tracked Source Thresholds
The Terabecquerel (TBq) values are the
regulatory standard. The curie (Ci) values
specified are obtained by converting from the
TBq value. The curie values are provided for
practical usefulness only and are rounded
after conversion.
Radioactive material |
Category 1
(TBq) |
Category 1
(Ci) |
Category 2
(TBq) |
Category 2
(Ci) |
Actinium-227 |
20 |
540 |
0.2 |
5.4 |
Americium-241 |
60 |
1,600 |
0.6 |
16 |
Americium-241/Be |
60 |
1,600 |
0.6 |
16 |
Californium-252 |
20 |
540 |
0.2 |
5.4 |
Cobalt-60 |
30 |
810 |
0.3 |
8.1 |
Curium-244 |
50 |
1,400 |
0.5 |
14 |
Cesium-137 |
100 |
2,700 |
1 |
27 |
Gadolinium-153 |
1,000 |
27,000 |
10 |
270 |
Iridium-192 |
80 |
2,200 |
0.8 |
22 |
Plutonium-238 |
60 |
1,600 |
0.6 |
16 |
Plutonium-239/Be |
60 |
1,600 |
0.6 |
16 |
Polonium-210 |
60 |
1,600 |
0.6 |
16 |
Promethium-147 |
40,000 |
1,100,000 |
400 |
11,000 |
Radium-226 |
40 |
1,100 |
0.4 |
11 |
Selenium-75 |
200 |
5,400 |
2 |
54 |
Strontium-90 |
1,000 |
27,000 |
10 |
270 |
Thorium-228 |
20 |
540 |
0.2 |
5.4 |
Thorium-229 |
20 |
540 |
0.2 |
5.4 |
Thulium-170 |
20,000 |
540,000 |
200 |
5,400 |
Ytterbium-169 |
300 |
8,100 |
3 |
81 |
[71 FR 65686, November 8, 2006]
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