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Information Directory

Reference Directory

Exempt Concentrations

Federal regulatory authorities consider certain concentrations of radioactive materials to be exempt from regulatory authority. In other words, one may possess up to the specified amount of a particular radionuclide without having to secure a radioactive materials license . However, this exemption does not apply to concentrations that may be commercially distributed. (Press the “Position Papers” category in the “References and Resources” section above to review several USNRC position papers on this topic.)

The following is the listing of exempt quantities, in units of “microcuries per milliliter” for liquids or gases, or “microcuries per gram” for solids, promulgated by the U. S. Nuclear Regulatory Commission in Title 10, Code of Federal Regulations, Part 30.  Agreement States may have additional requirements for the use of these materials or interpret these regulations in a different manner.  Please contact Plexus-NSD for guidance on state-specific requirements.

Antimony

  • Sb 122 – 3E-4
  • Sb 124 – 2E-4
  • Sb 125 – 1E-3

Argon

  • A 37 – 1E-3 (gas)
  • A 41 – 4E-7 (gas)

Arsenic

  • As 73 – 5E-3
  • As 74 – 5E-4
  • As 76 – 2E-4
  • As 77 – 8E-4

Barium

  • Ba 131 – 2E-3
  • Ba 140 – 3E-4

Beryllium

  • Be 7 – 2E-2

Bismuth

  • Bi 206 – 4E-4

Bromine

  • Br 82 – 4E-7 (gas)
  • Br 82 – 3E-3

Cadmium

  • Cd 109 – 2E-3
  • Cd 115m – 3E-4
  • Cd 115 – 3E-4

Calcium

  • Ca 45 – 9E-5
  • Ca 47 – 5E-4

Carbon

  • C 14  – 1E-6 (gas)
  • C-14 – 8E-3

Cerium

  • Ce 141 – 9E-4
  • Ce 143 – 4E-4
  • Ce 144 – 1E-4

Cesium

  • Cs 131 – 2E-2
  • Cs 134m – 6E-2
  • Cs 134 – 9E-5

Chlorine

  • Cl 38 – 9E-7 (gas)
  • Cl 38 – 4E-3

Chromium

  • Cr 51 – 2E-2

Cobalt

  • Co 57 – 5E-3
  • Co 58 – 1E-3
  • Co 60 – 5E-4

Copper

  • Cu 64 – 3E-3

Dysprosium

  • Dy 165 – 4E-3
  • Dy 166 – 4E-4

Erbium

  • Er 169 – 9E-4
  • Er 171 – 1E-3

Europium

  • Eu 152 – 6E-4 (T/2=9.2 Hrs).
  • Eu 155 – 2E-3

Fluorine

  • F 18 – 2E-6 (gas)
  • F 18 – 8E-3

Gadolinium

  • Gd 153 – 2E-3
  • Gd 159 – 8E-4

Gallium

  • Ga 72 – 4E-4

Germanium

  • Ge 71 – 2E-2

Gold

  • Au 196 – 2E-3
  • Au 198 – 5E-4
  • Au 199 – 2E-3

Hafnium

  • 181 – 7E-4

Hydrogen

  • H 3 – 5E-6 (gas)
  • H 3 – 3E-2

Indium

  • In 113m- 1E-2
  • In 114m- 2E-4

Iodine

  • I 126 3E-9 (gas)
  • I 126 – 2E-5
  • I 131 3E-9 (gas)
  • I 131- 2E-5
  • I 132 8E-8 (gas)
  • I 132 – 6E-4
  • I 133 1E-8 (gas)
  • I 133 – 7E-5
  • I 134 2E-7 (gas)
  • I 134 – 1E-3

Iridium

  • Ir 190 – 2E-3
  • Ir 192 – 4E-4
  • Ir 194 – 3E-4

Iron

  • Fe 55 – 8E-3
  • Fe 59 – 6E-4

Krypton

  • Kr 85m – 1E-6 (gas)
  • Kr 85 – 3E-6 (gas)

Lanthanum

  • La 140 – 2E-4

Lead

  • Pb 203 – 4E-3

Lutetium

  • Lu 177 – 1E-3

Manganese

  • Mn 52 – 3E-4
  • Mn 54 – 1E-3
  • Mn 56 – 1E-3

Mercury

  • Hg 197m – 2E-3
  • Hg 197 – 3E-3
  • Hg 203 – 2E-4

Molybdenum

  • Mo 99 – 2E-3

Neodymium

  • Nd 147 – 6E-4
  • Nd 149 – 3E-3

Nickel

  • Ni 65 – 1E-3

Niobium

  • Nb 95 – 1E-3
  • Nb 97 – 9E-3

Osmium

  • Os 185 – 7E-4
  • Os 191m – 3E-2
  • Os 191 – 2E-3
  • Os 193 – 6E-4

Palladium

  • Pd 103 – 3E-3
  • Pd 109 – 9E-4

Phosphorus

  • P 32 . – 2E-4

Platinum

  • Pt 191 – 1E-3
  • Pt 193m – 1E-2
  • Pt 197m – 1E-2
  • Pt 197 – 1E-3

Potassium

  • K 42 . – 3E-3

Praseodymium

  • Pr 142 – 3E-4
  • Pr 143 – 5E-4

Promethium

  • Pm 147 – 2E-3
  • Pm 149 – 4E-4

Rhenium

  • Re 183 – 6E-3
  • Re 186 – 9E-4
  • Re 188 – 6E-4

Rhodium

  • Rh 103m – 1E-1
  • Rh 105 – 1E-3

Rubidium

  • Rb 86 – 7E-4

Ruthenium

  • Ru 97 – 4E-4
  • Ru 103 – 8E-4
  • Ru 105 – 1E-3
  • Ru 106 – 1E-4

Samarium

  • Sm 153 – 8E-4

Scandium

  • Sc 46 – 4E-4
  • Sc 47 – 9E-4
  • Sc 48 – 3E-4

Selenium

  • Se 75 – 3E-3

Silicon

  • Si 31 – 9E-3

Silver

  • Ag 105 – 1E-3
  • Ag 110m – 3E-4
  • Ag 111 – 4E-4

Sodium

  • Na 24 – 2E-3

Strontium

  • Sr 85 – 1E-4
  • Sr 89 – 1E-4
  • Sr 91 – 7E-4
  • Sr 92 – 7E-4

Sulfur

  • S 35 – 9E-8 (gas)
  • S 35 – 6E-4

Tantalum

  • Ta 182 – 4E-4

Technetium

  • Tc 96m – 1E-1
  • Tc 96 – 1E-3

Tellurium

  • Te 125m – 2E-3
  • Te 127m – 6E-4
  • Te 127 – 3E-3
  • Te 129m – 3E-4
  • Te 131m – 6E-4
  • Te 132 – 3E-4

Terbium

  • Tb 160 – 4E-4

Thallium

  • Tl 200 – 4E-3
  • Tl 201 – 3E-3
  • Tl 202 – 1E-3
  • Tl 204 – 1E-3

Thulium

  • Tm 170 – 5E-4
  • Tm 171 – 5E-3

Tin

  • Sn 113 – 9E-4
  • Sn 125 – 2E-4

Tungsten

  • W 181 – 4E-3
  • W 187 – 7E-4

Vanadium

  • V 48 – 3E-4

Xenon

  • Xe 131m – 4E-6 (gas)
  • Xe 133 3E-6 (gas)
  • Xe 135 1E-6 (gas)

Ytterbium

  • Yb 175 – 1E-3

Yttrium

  • Y 90 . – 2E-4
  • Y 91m – 3E-2
  • Y 91 – 3E-4
  • Y 92 – 6E-4
  • Y 93 – 3E-4

Zinc

  • Zn 65 – 1E-3
  • Zn 69m – 7E-4
  • Zn 69 – 2E-2

Zirconium

  • Zr 95 – 6E-4
  • Zr 97 – 2E-4

Beta and/or gamma emitting byproduct material not listed above with half-life less than 3 years – 1E-10 (gas)

Beta and/or gamma emitting byproduct material not listed above with half-life less than 3 years – 1E-6