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Code of Federal Regulations (Last Updated: November 8, 2024) |
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Title 10 - Energy |
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Chapter I - Nuclear Regulatory Commission |
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Part 20 - Standards for Protection Against Radiation |
Appendix E to Part 20 - Nationally Tracked Source Thresholds
Latest version.
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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 65708, Nov. 8, 2006]