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Actinium, RadioactiveRadiation Limits / PotentialAtomic number 89; valence: 3; no stable nuclides; known isotopes (mass numbers): 209-233; naturally occurring isotopes: 227, 228; homologous with lanthanum; more basic than lanthanum; strong electropositive element; forms insoluble salts, e.g., carbonate, oxalate, phosphate, etc., just as the lanthanides; rapidly oxidizes to AcO3 in moist air /Actinium-225/ Atomic weight = 225.02322; half-life = 10.0 days; alpha emission, 5.935 MeV /Actinium-227/ Atomic weight = 227.027747; half-life = 21.77 years; negative beta emission, 0.045 MeV; alpha emission, 5.043 MeV /Actinium-228/ Atomic weight = 228.031014; half-life = 6.15 hours; negative beta emission, 2.127 MeV DECAY PATHWAY: Actinium-225, half-life 10.0 days, decays via alpha emission, 5.935 MeV, to francium-221, half-life 4.9 minutes. Francium-221 decays via alpha emission, 6.458 MeV, to astatine-227, half-life 32.2 minutes; decays via beta emission, 0.312 MeV, to radium-221, half-life 28 seconds. DECAY PATHWAY: Actinium-227, half-life 21.77 years, decays via beta emission (98.62%), 0.045 MeV, to thorium-227, half-life 7,340 years. Thorium-227 decays via alpha emission, 6.146 MeV, to radium-223, half-life 11.425 days. Actinium-227 decays via alpha emission (1.38%), 5.043 MeV, to francium-223, half-life 22.00 minutes. Francium-223 decays via beta emission, 1.149 MeV, to radium-223. DECAY PATHWAY: Actinium-228, half-life 6.15 hours, decays via beta emission, 2.127 MeV, to thorium-228, half-life 1.9116 years. ALI values have been established for individual radionuclides and are presented in Table 1 in Appendix B to PART 20.1001-20.2401. The ALI values for inhalation, presented in Column 2 in Table 1, correspond to a committed effective dose equivalent of 5 rems (0.05 Sv) or a committed dose equivalent of 50 rems (0.5 Sv) to any individual organ or tissue, whichever is more limiting. If the ALI value presented in Table 1 is limited by the 50-rem committed dose equivalent, the controlling organ is listed directly below the ALI value, and the stochastic ALI value based on the 5-rem committed effective dose equivalent is listed ... directly below the organ name. If a stochastic ALI is listed in parentheses, that value should be used to calculate the committed effective dose equivalent. OCCUPATIONAL VALUES FOR ACTINIUM-224
OCCUPATIONAL VALUES FOR ACTINIUM-225
OCCUPATIONAL VALUES FOR ACTINIUM-226
OCCUPATIONAL VALUES FOR ACTINIUM-227
OCCUPATIONAL VALUES FOR ACTINIUM-228
EFFLUENT CONCENTRATIONS ESTABLISHED BY THE NRC FOR SOME ACTINIUM COMPOUNDS
QUANTITIES OF NRC LICENSED MATERIAL REQUIRING LABELING
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