10 CFR Appendix E to Part 20, Nationally Tracked Source Thresholds

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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]

Title 10 published on 2015-12-04

The following are ALL rules, proposed rules, and notices (chronologically) published in the Federal Register relating to 10 CFR Part 20 after this date.

  • 2016-12-28; vol. 81 # 249 - Wednesday, December 28, 2016
    1. 81 FR 95410 - Rulemaking Activities Being Discontinued by the NRC
      GPO FDSys XML | Text
      NUCLEAR REGULATORY COMMISSION
      Rulemaking activities; discontinuation.
      Effective December 28, 2016, the rulemaking activities discussed in this document are discontinued.
      10 CFR Parts 20 and 50

Title 10 published on 2015-12-04.

The following are only the Rules published in the Federal Register after the published date of Title 10.

For a complete list of all Rules, Proposed Rules, and Notices view the Rulemaking tab.

  • 2016-12-28; vol. 81 # 249 - Wednesday, December 28, 2016
    1. 81 FR 95410 - Rulemaking Activities Being Discontinued by the NRC
      GPO FDSys: XML | Text
      NUCLEAR REGULATORY COMMISSION
      Rulemaking activities; discontinuation.
      Effective December 28, 2016, the rulemaking activities discussed in this document are discontinued.
      10 CFR Parts 20 and 50