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Footnotes for radionuclide tables in 10 CFR Part 20 Appendix B
Footnotes
1"Submersion" means that values given are for
submersion in a hemispherical semi-infinite cloud of airborne material.
2 These radionuclides have radiological half-lives
of less than 2 hours. The total effective dose equivalent received during
operations with these radionuclides might include a significant contribution
from external exposure. The DAC values for all radionuclides, other than
those designated Class "Submersion," are based upon the committed effective
dose equivalent due to the intake of the radionuclide into the body and
do not include potentially significant contributions to dose equivalent
from external exposures. The licensee may substitute 1E-7 µCi/ml for the
listed DAC to account for the submersion dose prospectively, but should
use individual monitoring devices or other radiation measuring instruments
that measure external exposure to demonstrate compliance with the limits.
(See § 20.1203.)
3 For soluble mixtures of U-238, U-234, and
U-235 in air, chemical toxicity may be the limiting factor (see §
20.1201(e)). If the percent by weight (enrichment) of U-235 is not greater
than 5, the concentration value for a 40-hour workweek is 0.2 milligrams
uranium per cubic meter of air average. For any enrichment, the product
of the average concentration and time of exposure during a 40-hour workweek
shall not exceed 8E-3 (SA) µCi-hr/ml, where SA is the specific activity
of the uranium inhaled. The specific activity for natural uranium is 6.77E-7
curies per gram U. The specific activity for other mixtures of U-238,
U-235, and U-234, if not known, shall be:
SA = 3.6E-7 curies/gram U for |
U-depleted |
SA = [0.4 + 0.38 (enrichment) + 0.0034 (enrichment)2]
E-6 , enrichment > 0.72 |
where enrichment is the percentage by weight of U-235, expressed
as percent.
NOTE:
If the identity of each radionuclide in a mixture is known but the
concentration of one or more of the radionuclides in the mixture is
not known, the DAC for the mixture shall be the most restrictive DAC
of any radionuclide in the mixture.
- If the identity of each radionuclide in the mixture is not known,
but it is known that certain radionuclides specified in this appendix
are not present in the mixture, the inhalation ALI, DAC, and effluent
and sewage concentrations for the mixture are the lowest values specified
in this appendix for any radionuclide that is not known to be absent
from the mixture; or
Radionuclide |
Table 1
Occupational Values |
Table 2
Effluent Concentrations |
Table 3
Releases to
Sewers |
Col. 1 |
Col. 2 |
Col. 3 |
Col. 1 |
Col. 2 |
Monthly
Average
Concentration
(µCi/ml) |
Oral
Ingestion
ALI
(µCi) |
Inhalation |
Air
(µCi/ml) |
Water
(µCi/ml) |
ALI
(µCi) |
DAC
(µCi/ml) |
If it is known that Ac-227-D and Cm-250-W are not present |
- |
7E-4 |
3E-13 |
- |
- |
- |
If, in addition, it is known that Ac-227-W,Y, Th-229-W,Y, Th-230-W, Th-232-W,Y, Pa-231-W,Y, Np-237-W, Pu-239-W, Pu-240-W, Pu-242-W, Am-241-W, Am-242m-W, Am-243-W, Cm-245-W, Cm-246-W, Cm-247-W, Cm-248-W, Bk-247-W, Cf-249-W, and Cf-251-W are not present |
- |
7E-3 |
3E-12 |
- |
- |
- |
If, in addition, it is known that Sm-146-W, Sm-147-W, Gd-148-D,W, Gd-152-D,W, Th-228-W,Y, Th-230-Y, U-232-Y, U-233-Y, U-234-Y, U-235-Y, U-236-Y, U-238-Y, Np-236-W, Pu-236-W,Y,
Pu-238-W,Y, Pu-239-Y, Pu-240-Y, Pu-242-Y, Pu-244-W,Y, Cm-243-W, Cm-244-W, Cf-248-W, Cf-249-Y, Cf-250-W,Y, Cf-251-Y, Cf-252-W,Y, and Cf-254-W,Y are not present |
- |
7E-2 |
3E-11 |
- |
- |
- |
If, in addition, it is known that Pb-210-D, Bi-210m-W, Po-210-D,W, Ra-223-W, Ra-225-W, Ra-226-W, Ac-225-D,W,Y, Th-227-W,Y, U-230-D,W,Y, U-232-D,W, Pu-241-W, Cm-240-W, Cm-242-W, Cf-248-Y, Es-254-W, Fm-257-W, and Md-258-W are not present |
- |
7E-1 |
3E-10 |
- |
- |
- |
If, in addition, it is known that Si-32-Y, Ti-44-Y, Fe-60-D, Sr-90-Y, Zr-93-D, Cd-113m-D, Cd-113-D, In-115-D,W, La-138-D, Lu-176-W, Hf-178m-D,W, Hf-182-D,W, Bi-210m-D, Ra-224-W, Ra-228-W, Ac-226-D,W,Y, Pa-230-W,Y, U-233-D,W, U-234-D,W, U-235-D,W, U-236-D,W, U-238-D,W, Pu-241-Y, Bk-249-W, Cf-253-W,Y, and Es-253-W are not present |
- |
7E+0 |
3E-9 |
- |
- |
- |
If it is known that Ac-227-D,W,Y, Th-229-W,Y, Th 232-W,Y, Pa-231-W,Y, Cm-248-W, and Cm-250-W are not present |
- |
- |
- |
1E-14 |
- |
- |
If, in addition, it is known that Sm-146-W, Gd-148-D,W, Gd-152-D, Th-228-W,Y, Th-230-W,Y,U-232-Y, U233-Y, U-235-Y, u-236-Y, U238-Y, U-Nat-Y, Mp-236-W, Mp-237-W, Pu-236-W,Y, Pu-238-W,Y, Pu-239-W,Y, Pu-240-W,Y, Pu-242-W,Y, Pu-244-W,Y, Am-241-W, Am-242m-W, Am-243-W, Cm-243-W, Cm-244-W, Cm-245-W, Cm-246-W, Cm-247-W, Bk-247-W, Cf-249-W,Y, Cf-250-W,Y, Cf-251-W,Y, Cf-252-W,Y, and Cf-254-W,Y are not present |
- |
- |
- |
1E-13 |
- |
- |
If, in addition, it is known that Sm-147-W, Gd-152-W, Pb-210-D, Bi-210m-W, Po-210-D,W, Ra-223-W, Ra-225-W, Ra-226-W, Ac-225-D,W,Y, Th-227-W,Y, U-230-D,W,Y, U-232-D,W, U-Nat-W, Pu-241-W, Cm-240-W, Cm-242-W, Cf-248-W,Y, Es-254-W, Fm-257-W, and Md-258-W are not present |
- |
- |
- |
1E-12 |
- |
- |
If, in addition it is known that Fe-60, Sr-90, Cd-113m, Cd-113, In-115, I-129, Cs-134, Sm-145, Sm-147, Gd-148, Gd-152, Hg-194 (organic), Bi-210m, Ra-223, Ra-224, Ra-225, Ac-225, Th-228, Th-230, U-233, U-234, U-235, U-236, U-238, U-Nat, Cm-242, Cf-248, Es-254, Fm-257, and Md-258 are not present |
- |
- |
- |
- |
1E-6 |
1E-5 |
If a mixture of radionuclides consists of uranium and its daughters in ore dust (10 µm AMAD particle distribution assumed) prior to chemical separation of the uranium from the ore, the following values may beused for the DAC of the mixture: 6E-11 µCi of gross alpha activity from uranium-238, uranium-234, thorium-230, and radium-226 per milliliter of air; 3E-11 µCi of natural uranium per milliliter of air; or 45 micrograms of natural uranium per cubic meter of air.
If the identity and concentration of each radionuclide in a mixture are known, the limiting values should be derived as follows: determine, for each radionuclide in the mixture, the ratio between the concentration present in the mixture and the concentration otherwise established in Appendix B for the specific radionuclide when not in a mixture. The sum of such ratios for all of the radionuclides in the mixture may not exceed "1" (i.e., "unity").
Example: If radionuclides "A," "B," and "C" are present in concentrations CA, CB, and CC, and if the applicable DACs are DACA, DACB, and DACC, respectively, then the concentrations shall be limited so that the following relationship exists:
CA |
+ |
CB |
+ |
CC |
< 1 |
|
|
|
DACA |
DACB |
DACC |
|