Selenium, Elemental

CAS RN:7782-49-2

Radiation Limits / Potential

Selenium Decay Pathways
Natural Isotopes

Isotope Relative % Abundance Half-life Mode of Decay Decay energy
Selenium-74 0.89 Stable
Selenium-76 9.36 Stable
Selenium-77 7.63 Stable
Selenium-78 23.78 Stable
Selenium-80 49.61 Stable
Selenium-82 8.73 1.08X10+20(+26-6) years 2 Beta to Krypton-82 2.995 MeV
Selenium Decay Pathways
Artificial Isotopes

Isotope Half-life Mode of Decay Decay Energy (MeV)
Selenium-65 <50 milli sseconds electron capture to As-65 14.100
Selenium-66 >1.2 micro secondss electron capture to As-66 1.100
Selenium-67 60 milli seconds electron capture to AS-67 7.840
Selenium-68 35.5 seconds electron capture to AS-68 4.700
Selenium-69 27.4 seconds electron capture to AS-69 6.780
electron cpaure + proton to Ge-68 3.390
Selenium-70 41.1 minutes electron capture to AS-70 2.400
Selenium-71 4.74 minutes electron capture to AS-71 4.800
Selenium-72 8.40 days electron capture to AS-72 0.335
Selenium-73 7.15 hrs electron capture to AS-73 2.740
Selenium-75 119.79 days electron capture to AS-75 0.864
Selenium-79 <= 650,000 years beta to Br-79 0.151
Selenium-81 18.45 minutes beta to Br-81 1.585
Selenium-83 22.3 minutes beta to Br-83 3.668
Selenium-84 3.10 minutes beta to Br-84 1.830
Selenium-85 31.7 seconds beta to Br-85 6.182
Selenium-86 15.3 seconds beta to Br-86 5.099
Selenium-87 5.29 seconds beta to Br-87 7.280
beta + neutron to Br-86 0.990
Selenium-88 1.53 seconds beta to Br-88 6.850
beta + neutron to Br-87 1.910
Selenium-89 0.41 seconds beta to Br-89 9.000
beta + neutron to Br-88 3.100
Selenium-90 >150 nanoseconds
Selenium-91 0.27 seconds beta to Br-91 10.700
beta + neutron to Br-90 5.700
Selenium-92 >150 nanoseconds beta to Br-92 9.400
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 SELENIUM (Class W, oxides, hydroxides, carbides, and elemental Se. Class D, all compounds except those given for W)
RADIONUCLIDE ORAL Ingestion ALI (uCi) INHALATION ALI (uCi) INHALATION DAC (uCi/mL)
Selenium-70, Class D 2E+4 4E+4 2E-5
Selenium-70, Class W 1E+4 4E+4 2E-5
Selenium-73, Class D 3E+3 1E+4 5E-6
Selenium-73, Class W - 2E+4 7E-6
Selenium-73m, Class D 6E+4 2E+5 6E-5
Selenium-73m, Class W 3E+4 1E+5 6E-5
Selenium-75, Class D 5E+2 7E+2 3E-7
Selenium-75, Class W - 6E+2 3E-7
Selenium-79, Class D 6E+2 8E+2 3E-7
Selenium-79, Class W - 6E+2 2E-7
Selenium-81, Class D 6E+4 (St. wall) 2E+5 9E-5
Selenium-81, Class W - 2E+5 1E-4
Selenium-81m, Class D 4E+4 7E+4 3E-5
Selenium-81m, Class W 2E+4 7E+4 3E-5
Selenium-83, Class D 4E+4 1E+5 5E-5
Selenium-83, Class W 3E+4 1E+5 5E-5
EFFLUENT CONCENTRATIONS ESTABLISHED BY THE NRC FOR SOME SELENIUM COMPOUNDS
RADIONUCLIDE EFLUENT CONCENTRATION: Air (uCi/mL) EFFLUENT CONCENTRATION: Water (uCi/mL)
Selenium-70, Class D 5E-8 1E-4
Selenium-70, Class W 6E-8 -
Selenium-73, Class D 2E-8 4E-5
Selenium-73, Class W 2E-8 -
Selenium-73m, Class D 2E-7 4E-4
Selenium-73m, Class W 2E-7 -
Selenium-75, Class D 1E-9 7E-6
Selenium-75, Class W 8E-10 -
Selenium-79, Class D 1E-9 8E-6
Selenium-79, Class W 8E-10 -
Selenium-81, Class D 3E-7 1E-3
Selenium-81, Class W 3E-7 -
Selenium-81m, Class D 9E-8 3E-4
Selenium-81m, Class W 1E-7 -
Selenium-83, Class D 2E-7 4E-4
Selenium-83, Class W 2E-7 -
QUANTITIES OF NRC LICENSED MATERIAL REQUIRING LABELING
RADIONUCLIDE QUANTITY (uCi)
Selenium-70 1,000
Selenium-73m 1,000
Selenium-73 100
Selenium-75 100
Selenium-79 100
Selenium-81m 1,000
Selenium-81 1,000
Selenium-83 1,000
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