{"data":{"id":"us/49-cfr-173.434","jurisdiction":"us","citation":"49 CFR 173.434","heading":"Activity-mass relationships for uranium and natural thorium.","body":"The table of activity-mass relationships for uranium and natural thorium are as follows:\nThorium and uranium enrichment 1 (Wt% 235 U present) Specific activity\nTBq/gram Grams/Tbq Ci/gram Grams/Ci\n0.45 (depleted) 1.9 × 10−8 5.4 × 107 5.0 × 10−7 2.0 × 106\n0.72 (natural) 2.6 × 10−8 3.8 × 107 7.1 × 10−7 1.4 × 106\n1.0 2.8 × 10−8 3.6 × 107 7.6 × 10−7 1.3 × 106\n1.5 3.7 × 10−8 2.7 × 107 1.0 × 10−6 1.0 × 106\n5.0 1.0 × 10−7 1.0 × 107 2.7 × 10−6 3.7 × 105\n10.0 1.8 × 10−7 5.6 × 106 4.8 × 10−6 2.1 × 105\n20.0 3.7 × 10−7 2.7 × 106 1.0 × 10−5 1.0 × 105\n35.0 7.4 × 10−7 1.4 × 106 2.0 × 10−5 5.0 × 104\n50.0 9.3 × 10−7 1.1 × 106 2.5 × 10−5 4.0 × 104\n90.0 2.1 × 10−6 4.7 × 105 5.8 × 10−5 1.7 × 104\n93.0 2.6 × 10−6 3.9 × 105 7.0 × 10−5 1.4 × 104\n95.0 3.4 × 10−6 3.0 × 105 9.1 × 10−5 1.1 × 104\nNatural thorium 8.1 × 10−9 1.2 × 108 2.2 × 10−7 4.6 × 106\n1 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.","path":["Title 49—Transportation","Subtitle B—Other Regulations Relating to Transportation","CHAPTER I—PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION","SUBCHAPTER C—HAZARDOUS MATERIALS REGULATIONS","PART 173—SHIPPERS—GENERAL REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS","Subpart I—Class 7 (Radioactive) Materials"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-49.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:34Z","sha256":"2792ba42b5dff88217b79265a9c06b06031ca29580856ad1c9ffda5767a1c6fe","source_id":"us-cfr","stale":true,"prev":"us/49-cfr-173.433","next":"us/49-cfr-173.435"},"notice":"GroundRules: Original legal text. Not legal advice."}