where f(i) is the fraction of activity of nuclide (i) in the mixture and A1(i) is the appropriate A1 value for nuclide i.
(e) Alternatively the A2 value for mixtures of normal form material may be determined as follows:
where f(i) is the fraction of activity for radionuclide (i) in the mixture, and A2 (i) is the appropriate A2 value for radionuclide (i).
(f) The exempt activity concentration for mixtures of nuclides may be determined as follows:
where f(i) is the fraction of activity concentration of radionuclide (i) in the mixture, and [A] is the activity concentration for exempt material containing radionuclide (i).
(g) The activity limit for an exempt consignment for mixtures of radionuclides may be determined as follows:
where f(i) is the fraction of activity of radionuclide (i) in the mixture, and A is the activity limit for exempt consignments for radionuclide (i).
V. (a) When the identity of each radionuclide is known, but the individual activities of some of the radionuclides are not known, the radionuclides may be grouped and the lowest A1 or A2 value, as appropriate, for the radionuclides in each group may be used in applying the formulas in paragraph IV. Groups may be based on the total alpha activity and the total beta/gamma activity when these are known, using the lowest A1 or A2 values for the alpha emitters and beta/gamma emitters.
(b) When the identity of each radionuclide is known but the individual activities of some of the radionuclides are not known, the radionuclides may be grouped and the lowest [A] (activity concentration for exempt material) or A (activity limit for exempt consignment) value, as appropriate, for the radionuclides in each group may be used in applying the formulas in paragraph IV. Groups may be based on the total alpha activity and the total beta/gamma activity when these are known, using the lowest [A] or A values for the alpha emitters and beta/gamma emitters, respectively.
NOTES
(a) A1 and/or A2 values include contributions from daughter nuclides with half-lives less than 10 days, as listed in the following:
(b) The values of A1 and A2 in curies (Ci) are approximate and for information only; the regulatory standard units are Terabecquerels (TBq).
(c) The activity of Ir-192 in special form may be determined from a measurement of the rate of decay or a measurement of the radiation level at a prescribed distance from the source.
(d) These values apply only to compounds of uranium that take the chemical form of UF6, UO2F2 and UO2(NO3)2 in both normal and accident conditions of transport.
(e) These values apply only to compounds of uranium that take the chemical form of UO3, UF4, UCl4, and hexavalent compounds in both normal and accident conditions of transport.
(f) These values apply to all compounds of uranium other than those specified in (d) and (e), above.
(g) These values apply to unirradiated uranium only.
(h) A2 = 0.74 TBq (20 Ci) for Mo-99 for domestic use.
NOTES
(a) Parent nuclides and their progeny included in secular equilibrium are listed in the following:
(b) These values apply only to compounds of uranium that take the chemical form of UF6, UO2F2, and UO2(NO3)2 in both normal and accident conditions of transport.
(c) These values apply only to compounds of uranium that take the chemical form of UO3, UF4, UCl4, and hexavalent compounds in both normal and accident conditions of transport.
(d) These values apply to all compounds of uranium other than those specified in (d) and (e), above.
(e) These values apply to unirradiated uranium only.
(a) If beta or gamma emitting nuclides are known to be present, the A1 value of 0.1 TBq (2.7 Ci) should be used.
Note: The figures for uranium include representative values for the activity of the uranium-234 that is concentrated during the enrichment process.
