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

View PDF at GPO Pt. 20, App. E
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 2014-01-01

no entries appear in the Federal Register after this date.

Title 10 published on 2014-01-01

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

  • 2014-07-25; vol. 79 # 143 - Friday, July 25, 2014
    1. 79 FR 43284 - Radiation Protection
      GPO FDSys XML | Text
      NUCLEAR REGULATORY COMMISSION
      Advance notice of proposed rulemaking; request for comments.
      Submit comments by November 24, 2014. Comments received after this date will be considered if it is practical to do so, but the NRC is only able to ensure consideration of comments received on or before this date.
      10 CFR Part 20