10 C.F.R. Appendix C to Part 835—Derived Air Concentrations (DAC) for Workers From External Exposure During Immersion in a Contaminated Atmospheric Cloud
Title 10 - Energy
a. The data presented in appendix C are to be used for controlling occupational exposures in accordance with §835.209, identifying the need for air monitoring in accordance with §835.403, and identifying the need for posting of airborne radioactivity areas in accordance with §835.603(d). b. The air immersion DAC values shown in this appendix are based on a stochastic dose limit of 5 rems (0.05 Sv) per year or a nonstochastic (organ) dose limit of 50 rems (0.5 Sv) per year. Four columns of information are presented: (1) Radionuclide; (2) half-life in units of seconds (s), minutes (min), hours (h), days (d), or years (yr); (3) air immersion DAC in units of µCi/ml; and (4) air immersion DAC in units of Bq/m3 . The data are listed by radionuclide in order of increasing atomic mass. The air immersion DACs were calculated for a continuous, nonshielded exposure via immersion in a semi-infinite atmospheric cloud. The DACs listed in this appendix may be modified to allow for submersion in a cloud of finite dimensions. c. The DAC value for air immersion listed for a given radionuclide is determined either by a yearly limit on effective dose equivalent, which provides a limit on stochastic radiation effects, or by a limit on yearly dose equivalent to any organ, which provides a limit on nonstochastic radiation effects. For most of the radionuclides listed, the DAC value is determined by the yearly limit on effective dose equivalent. Thus, the few cases where the DAC value is determined by the yearly limit on shallow dose equivalent to the skin are indicated in the table by an appropriate footnote. Again, the DACs listed in this appendix account only for immersion in a semi-infinite cloud and do not account for inhalation or ingestion exposures. d. Three classes of radionuclides are included in the air immersion DACs as described below. (1) Class 1. The first class of radionuclides includes selected noble gases and short-lived activation products that occur in gaseous form. For these radionuclides, inhalation doses are negligible compared to the external dose from immersion in an atmospheric cloud. (2) Class 2. The second class of radionuclides includes those for which a DAC value for inhalation has been calculated, but for which the DAC value for external exposure to a contaminated atmospheric cloud is more restrictive (i.e., results in a lower DAC value). These radionuclides generally have half-lives of a few hours or less, or are eliminated from the body following inhalation sufficiently rapidly to limit the inhalation dose. (3) Class 3. The third class of radionuclides includes selected isotopes with relatively short half-lives. These radionuclides typically have half-lives that are less than 10 minutes, they do not occur as a decay product of a longer lived radionuclide, or they lack sufficient decay data to permit internal dose calculations. These radionuclides are also typified by a radioactive emission of highly intense, high-energy photons and rapid removal from the body following inhalation. e. The DAC values are given for individual radionuclides. For known mixtures of radionuclides, determine the sum of the ratio of the observed concentration of a particular radionuclide and its corresponding DAC for all radionuclides in the mixture. If this sum exceeds unity (1), then the DAC has been exceeded. For unknown radionuclides, the most restrictive DAC (lowest value) for those isotopes not known to be absent shall be used. [58 FR 65485, Dec. 14, 1993, as amended at 63 FR 59687, Nov. 4, 1998]
Title 10: Energy
PART 835—OCCUPATIONAL RADIATION PROTECTION
Subpart N—Emergency Exposure Situations
Appendix C to Part 835—Derived Air Concentrations (DAC) for Workers From External Exposure During Immersion in a Contaminated Atmospheric Cloud
------------------------------------------------------------------------ Air Immersion DAC Radionuclide Half-Life ----------------------------------- (µCi/ml) (Bq/m \3\)------------------------------------------------------------------------C-11 20.48 min......... 4.E-06 1.E+05N-13 9.97 min.......... 4.E-06 1.E+05N-16 7.13 s............ 7.E-07 3.E+04O-15 122.24 s.......... 4.E-06 1.E+05F-18 \1\ 109.74 min........ 4.E-06 1.E+05Na-24 \1\ 15.00 h........... 9.E-07 3.E+04Mg-27 \2\ 9.458 min......... 5.E-06 2.E+05Al-28 \2\ 2.240 min......... 2.E-06 7.E+04Cl-38 \1\ 37.21 min......... 3.E-06 1.E+05Ar-37 35.02 d........... 3.E+00 1.E+11Ar-39 269 yr............ 2.E-04 \3\ 7.E+06 \3\Ar-41 1.827 h........... 3.E-06 1.E+05K-43 \1\ 22.6 h............ 5.E-06 2.E+05Ca-492 8.719 min......... 1.E-06 4.E+04Sc-44 \1\ 3.927 h........... 2.E-06 7.E+04Sc-46m \2\ 18.72 s........... 5.E-05 2.E+06Ti-45 \1\ 3.08 h............ 5.E-06 2.E+05Ti-51 \2\ 5.752 min......... 1.E-05 4.E+05V-52 \2\ 3.75 min.......... 3.E-06 1.E+05Cr-49 \1\ 42.09 min......... 5.E-06 2.E+05Mn-52m \1\ 21.4 min.......... 2.E-06 7.E+04Mn-56 \1\ 2.5785 h.......... 2.E-06 7.E+04Mn-57 \2\ 1.47 min.......... 6.E-05 2.E+06Co-60m \1\ 10.47 min......... 1.E-03 4.E+07Ni-57 \1,4\ 36.08 h........... 2.E-06 7.E+04Ni-65 \1,5\ 2.520 h........... 8.E-06 3.E+05Cu-61 \1\ 3.408 h........... 5.E-06 2.E+05Cu-62 \2\ 9.74 min.......... 5.E-06 2.E+05Ga-66 \1\ 9.40 h............ 2.E-06 7.E+04Ga-68 \1\ 68.0 min.......... 5.E-06 2.E+05Ga-72 \1\ 14.1 h............ 1.E-06 4.E+04Se-73 \1\ 7.15 h............ 4.E-06 1.E+05Br-77 \1\ 57.04 h........... 1.E-05 \6\ 4.E+05 \6\Br-80 \1\ 17.4 min.......... 5.E-05 2.E+06Br-82 \1\ 35.30 h........... 1.E-06 4.E+04Br-84 \1\ 31.80 min......... 2.E-06 7.E+04Br-85 \2\ 172 s............. 5.E-05 2.E+06Kr-79 35.04 h........... 2.E-05 7.E+05Kr-81 2.1E+05 yr........ 5.E-04 2.E+07Kr-83m 1.83 h............ 5.E-02 2.E+09Kr-85 10.72 yr.......... 1.E-04 \3\ 4.E+06 \3\Kr-85m 4.48 h............ 3.E-05 1.E+06Kr-87 76.3 min.......... 5.E-06 2.E+05Kr-88 2.84 h............ 2.E-06 7.E+04Kr-89 3.16 min.......... 2.E-06 7.E+04Kr-90 32.32 s........... 3.E-06 1.E+05Rb-81 \1\ 4.58 h............ 8.E-06 3.E+05Rb-82 \2\ 1.25 min.......... 2.E-06 7.E+04Rb-88 \1\ 17.8 min.......... 7.E-06 3.E+05Rb-89 \1\ 15.44 min......... 2.E-06 7.E+04Rb-90 \2\ 157 s............. 2.E-06 7.E+04Rb-90m \2\ 258 s............. 1.E-06 4.E+04Sr-85m \1\ 67.66 min......... 2.E-05 7.E+04Sr-87m \1\ 2.805 h........... 6.E-05 2.E+06Sr-92 \1\ 2.71 h............ 3.E-06 1.E+05Sr-93 \2\ 7.3 min........... 2.E-06 7.E+04Y-86 \1\ 14.74 h........... 1.E-06 4.E+04Y-90m \1\ 3.19 h............ 5.E-06 \6\ 2.E+05 \6\Y-91m \1\ 49.71 min......... 9.E-06 3.E+05Nb-90 \1\ 14.60 h........... 1.E-07 4.E+03Nb-94m \2\ 6.26 min.......... 9.E-04 3.E+07Nb-97 \1\ 72.1 min.......... 7.E-06 3.E+05Nb-97m \1\ 60 s.............. 6.E-06 2.E+05Mo-91 \2\ 15.9 min.......... 4.E-06 1.E+05Mo-101 \1\ 14.61 min......... 3.E-06 1.E+05Tc-95 \1\ 20.0 h............ 5.E-06 2.E+05Tc-96m \1\ 51.5 min.......... 1.E-04 4.E+06Tc-99m \1\ 6.02 h............ 3.E-05 1.E+06Tc-101 \1\ 14.2 min.......... 1.E-05 4.E+05Ru-105 \1\ 4.44 h............ 5.E-06 2.E+05Rh-105m \2\ 45 s.............. 1.E-04 4.E+06Rh-106 \2\ 29.92 s........... 2.E-05 7.E+05Ag-108 \2\ 2.37 min.......... 2.E-04 7.E+06Ag-109m \2\ 39.6 s............ 1.E-03 4.E+07Ag-110 \2\ 24.57 s........... 9.E-05 3.E+06Cd-111m \2\ 48.7 min.......... 1.E-05 4.E+05Cd-117 \1\ 2.49 h............ 4.E-06 1.E+05Cd-117m \1\ 3.36 h............ 2.E-06 7.E+04In-113m \1\ 1.658 h........... 2.E-05 7.E+05In-114 \2\ 71.9 s............ 1.E-04 4.E+06In-116m \1\ 54.15 min......... 2.E-06 7.E+04In-117 \1\ 43.8 min.......... 7.E-06 3.E+05Sb-117 \1\ 2.80 h............ 3.E-05 1.E+06Sb-126m \1\ 19.0 min.......... 3.E-06 1.E+05Sb-129 \1\ 4.40 h............ 3.E-06 1.E+05Te-133 \1\ 12.45 min......... 5.E-06 2.E+05Te-133m \1\ 55.4 min.......... 2.E-06 7.E+04Te-134 \1\ 41.8 min.......... 5.E-06 2.E+05I-122 \2\ 3.62 min.......... 5.E-06 2.E+05I-128 \1\ 24.99 min......... 5.E-05 2.E+06I-132 \1\ 2.30 h............ 2.E-06 7.E+04I-134 \1\ 52.6 min.......... 1.E-06 4.E+04I-135 \1\ 6.61 h............ 7.E-07 \6\ 3.E+04 \6\I-136 \2\ 83 s.............. 1.E-06 4.E+04Xe-122 20.1 h............ 8.E-05 3.E+06Xe-123 2.14 h............ 7.E-06 3.E+05Xe-125 16.8 h............ 2.E-05 7.E+05Xe-127 36.406 d.......... 1.E-05 4.E+05Xe-129m 8.89 d............ 2.E-04 7.E+06Xe-131m 11.84 d........... 5.E-04 2.E+07Xe-133 5.245 d........... 1.E-04 4.E+06Xe-133m 2.19 d............ 1.E-04 4.E+06Xe-135 9.11 h............ 2.E-05 7.E+05Xe-135m 15.36 min......... 1.E-05 4.E+05Xe-137 3.83 min.......... 2.E-05 7.E+05Xe-138 14.13 min......... 4.E-06 1.E+05Cs-126 \2\ 1.64 min.......... 4.E-06 1.E+05Cs-129 \1\ 32.06 h........... 1.E-05 \6\ 4.E+05 \6\Cs-138 \1\ 32.2 min.......... 2.E-06 7.E+04Cs-139 \2\ 9.40 min.......... 1.E-05 4.E+05Ba-137m \2\ 2.552 min......... 7.E-06 3.E+05Ba-141 \1\ 18.27 min......... 5.E-06 2.E+05Ba-142 \1\ 10.70 min......... 5.E-06 2.E+05La-142 \1\ 95.4 min.......... 1.E-06 4.E+04Pr-144m \2\ 7.2 min........... 9.E-04 3.E+07Nd-149 \1\ 1.73 h............ 1.E-05 4.E+05Gd-162 \2\ 9.7 min........... 1.E-05 4.E+05Td-162 \2\ 7.76 min.......... 4.E-06 1.E+05Dy-157 \1\ 8.06 h............ 1.E-05 4.E+05Re-182m \1\ 12.7 h............ 4.E-06 1.E+05Os-190m \2\ 9.9 min........... 3.E-06 1.E+05Ir-190m \1\ 3.2 h............. 8.E-05 \6\ 3.E+06 \6\Au-195m \2\ 30.6 s............ 2.E-05 7.E+05Tl-200 \1\ 26.1 h............ 3.E-06 1.E+05Tl-207 \2\ 4.77 min.......... 4.E-05 \3\ 1.E+06 \3\Tl-208 \2\ 3.053 min......... 1.E-06 4.E+04Tl-209 \2\ 2.20 min.......... 2.E-06 7.E+04Tl-210 \2\ 1.30 min.......... 1.E-06 4.E+04Pb-204m \2\ 66.9 min.......... 2.E-06 7.E+04Bi-211 \2\ 2.13 min.......... 1.E-04 4.E+06Po-211 \2\ 0.516 s........... 5.E-04 2.E+07Th-233 \2\ 22.3 min.......... 1.E-04 4.E+06Pa-234 \1\ 6.70 h............ 2.E-06 7.E+04Pa-234m \2\ 1.17 min.......... 4.E-05 \3\ 1.E+06 \3\U-239 \1\ 23.40 min......... 8.E-05 \6\ 3.E+06 \6\Np-240 \1\ 65 min............ 4.E-06 1.E+05Np-240m \2\ 7.4 min........... 1.E-05 4.E+05Am-246 \1\ 25.0 min.......... 4.E-06 1.E+05------------------------------------------------------------------------\1\ Committed effective dose equivalent from inhalation is calculated in ICRP Publication 30, but the DAC value for external exposure to a contaminated atmospheric cloud is more restrictive than the DAC value for inhalation.\2\ Committed effective dose equivalent from inhalation is not calculated in ICRP Publication 30, but DAC value for external exposure to contaminated cloud should be more restrictive than DAC value for inhalation due to relatively short half-life of radionuclide.\3\ DAC value is determined by limit on annual shallow dose equivalent to skin, rather than yearly limit on effective dose equivalent.\4\ DAC value applies to radionuclide in vapor form only; DAC value for inhalation is more restrictive for radionuclide in inorganic form.\5\ DAC value applies to radionuclide in inorganic or vapor form.\6\ DAC value for exposure to contaminated atmospheric cloud is the same as DAC value for inhalation.
