NASA Procedures and Guidelines

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NPR 8715.3

Eff. Date: January 24, 2000

Cancellation Date: September 12, 2006

NASA Safety Manual w/Change 2, 03/31/04

| TOC | Change | Preface | Chapter1 | Chapter2 | Chapter3 | Chapter4 | Chapter5 | Chapter6 | Chapter7 | Chapter8 | Chapter9 | AppendixA | AppendixB | AppendixC | AppendixD | AppendixE | AppendixF | AppendixG | AppendixH | AppendixI | AppendixJ | AppendixK | ALL |

This section has been reproduced with permission of the IAEA.

Appendix G. Activity and Radioactive Material Limits Basic A_l /A₂ Values

1. Values of A₁and A₂ for individual radionuclides, which are the basis for many activity limits elsewhere in this NPR, are given in Table I.

DETERMINATION OF A₁ AND A₂

2. For individual radionuclides whose identities are known, but which are not listed in Table I, the determination of the values of A₁ and A₂shall require competent authority approval or, for international transport, multilateral approval. Alternatively, the values of A₁ and A₂in Table II may be used without obtaining competent authority approval.

3. In the calculations of A₁ and A₂ for a radionuclide not in Table I, a single radioactive decay chain in which the radionuclides are present in their naturally occurring proportions and in which no daughter nuclide has a half-life either longer than 10 days or longer than that of the parent nuclide shall be considered as a single radionuclide, and the activity to be taken into account and the A₁or A₂ value to be applied shall be those corresponding to the parent nuclide of that chain. In the case of radioactive decay chains in which any daughter nuclide has a half-life either longer than 10 days or greater than that of the parent nuclide, the parent and such daughter nuclides shall be considered as mixtures of different nuclides.

4. For mixtures of radionuclides whose identities and respective activities are known, the following conditions shall apply:

(a) For special form radioactive material:

(b) For other forms of radioactive material:

where B(i) is the activity of radionuclide i and A₁(i) and A₂(i) are the A₁ and A₂ values for radionuclide i, respectively.

TABLE I. A₁ and A₂ VALUES FOR RADIONUCLIDES

Symbol of radionuclide	Element and atomic number	A₁(TBq)	A_l(Ci)	A₂ (TBq) (approx. ^a)	A₂ (Ci) (approx. ^a)
²²⁵Ac (b)* ²²⁷Ac ²²⁸Ac	Actinium (89)	0.6 40 0.6	10 1000 10	1 x 10^-22 x 10^-1 2 x 10^-55 x 10^-4 0.4	10
¹⁰⁵Ag ¹⁰⁸Ag^m ¹¹⁰Ag^m ¹¹¹Ag	Silver (47)	2 0.6 0.4 0.6	50 10 10 10	2 0.6 0.4 0.6	50 10 10 10
²⁶Al	Aluminum (13)	0.4	10	0.4	10
^24lAm ²⁴²Am^m ²⁴³Am	Americium (95)	2 2 2	50 50 50	2 x 10^-45 x 10^-3 2 x 10^-45 x 10^-3 2 x 10^-45 x 10^-3
³⁷Ar ³⁹Ar ^4lAr ⁴²Ar (b)	Argon (18)	40 20 0.6 0.2	1000 500 10 5	40 20 0.6 0.2	1000 500 10 5
⁷²As ⁷³As ⁷⁴As ⁷⁶As ⁷⁷As	Arsenic(33)	0.2 40 1 0.2 20	5 1000 20 5 500	0.2 40 0.5 0.2 0.5	5 1000 10 5 10
²¹¹At	Astatine (85)	30	800	2	50

* Note: (b) indicates a footnote at the end of Table I: this form is used to avoid confusion with the superscript m.

TABLE I. A_lAND A₂ VALUES FOR RADIONUCLIDES (Continued)

Symbol of radionuclide	Element and atomic number	A₁(TBq)	A_l(Ci)	A₂ (TBq) (approx. ^a)	A₂ (Ci) (approx. ^a)
¹⁹³Au ¹⁹⁴Au ¹⁹⁵Au ¹⁹⁶Au ¹⁹⁸Au ¹⁹⁹Au	Gold (79)	6 1 10 2 3 10	100 20 200 50 80 200	6 1 10 2 0.5 0.9	100 20 200 50 10 20
¹³¹Ba ¹³³Ba^m ¹³³Ba ¹⁴⁰Ba (b)	Barium (56)	2 10 3 0.4	50 200 80 10	2 0.9 3 0.4	50 20 80 10
⁷Be ¹⁰Be	Beryllium (4)	20 20	500 500	20 0.5	500 10
²⁰⁵Bi ²⁰⁶Bi ²⁰⁷Bi ²¹⁰Bi^m(b) ²¹⁰Bi ²¹²Bi (b)	Bismuth (83)	0.6 0.3 0.7 0.3 0.6 0.3	10 8 10 8 10 8	0.6 0.3 0.7 3 x 10^-28 x 10^-1 0.5 0.3 .	10 8 10 10 8
²⁴⁷Bk ²⁴⁹Bk	Berkelium (97)	2 40	50 1000	2 x 10^-45 x 10^-3 8 x 10^-22
⁷⁶Br ⁷⁷Br ⁸²Br	Bromine (35)	0.3 3 0.4	8 80 10	0.3 3 0.4	8 80 10
¹¹C ¹⁴C	Carbon (6)	1 40	20 1000	0.5 2	10 50
⁴¹Ca ⁴⁵Ca ⁴⁷Ca	Calcium (20)	40 40 0.9	1000 1000 20	40 0.9 0.5	1000 20 10
¹⁰⁹Cd ¹¹³Cd^m ¹¹⁵Cd^m ¹¹⁵Cd	Cadmium (48)	40 20 0.3 4	1000 500 8 100	1 9 x 10^-22 0.3 0.5	20 8 10
¹³⁹Ce ¹⁴¹Ce ¹⁴³Ce ¹⁴⁴Ce (b)	Cerium (58)	6 10 0.6 0.2	100 200 10 5	6 0.5 0.5 0.2	100 10 10 5

TABLE I. A_lAND A₂ VALUES FOR RADIONUCLIDES (Continued)

Symbol of radionuclide	Element and atomic number	A₁(TBq)	A_l(Ci)	A₂ (TBq) (approx. ^a)	A₂ (Ci) (approx. ^a)
²⁴⁸Cf ²⁴⁹Cf ²⁵⁰Cf ²⁵¹Cf ²⁵²Cf ²⁵³Cf ²⁵⁴Cf	Californium (98)	30 2 5 2 0.1 40 3 x 10^-38 x 10^-2	800 50 100 50 2 1000 6 x 10^-41 x 10^-2	3 x 10^-38 x 10^-2 2 x 10^-45 x 10^-3 5 x 10^-41 x l0^-2 2 x 10^-45 x 10^-3 1 x 10^-32 x 10^-2 6 x 10^-21
³⁶Cl ³⁸Cl	Chlorine (17)	20 0.2	500 5	0.5 0.2	10 5
²⁴⁰Cm ²⁴¹Cm ²⁴²Cm ²⁴³Cm ²⁴⁴Cm ²⁴⁵Cm ²⁴⁶Cm ²⁴⁷Cm ²⁴⁸Cm	Curium (96)	40 2 40 3 4 2 2 2 4 x 10^-21	1000 50 1000 80 100 50 50 50 5 x 10^-5	2 x 10^-25 x 10^-1 0.9 1 x 10^-22 x 10^-1 3 x 10^-48 x 10^-3 4 x 10^-41 x 10^-2 2 x 10^-45 x 10^-3 2 x 10^-45 x 10^-3 2 x 10^-45 x 10^-3 1 x 10^-3	20
⁵⁵Co ⁵⁶Co ⁵⁷Co ⁵⁸Co^m ⁵⁸Co ⁶⁰Co	Cobalt (27)	0.5 0.3 8 40 1 0.4	10 8 200 1000 20 10	0.5 0.3 8 40 1 0.4	10 8 200 1000 20 10

TABLE I. A_lAND A₂ VALUES FOR RADIONUCLIDES (Continued)

Symbol of radionuclide	Element and atomic number	A₁(TBq)	A_l(Ci)	A₂ (TBq) (approx. ^a)	A₂ (Ci) (approx. ^a)
^5lCr	Chromium (24)	30	800	30	800
¹²⁹Cs ¹³¹Cs ¹³²Cs ¹³⁴Cs^m ¹³⁴Cs ¹³⁵Cs ¹³⁶Cs ¹³⁷Cs (b)	Caesium (55)	4 40 1 40 0.6 40 0.5 2	100 1000 20 1000 10 1000 10 50	4 40 1 9 0.5 0.9 0.5 0.5	100 1000 20 200 10 20 10 10
⁶⁴Cu ⁶⁷Cu	Copper (29)	5 9	100 200	0.9 0.9	20 20
¹⁵⁹Dy ¹⁶⁵Dy ¹⁶⁶Dy (b)	Dysprosium (66)	20 0.6 0.3	500 10 8	20 0.5 0.3	500 10 8
¹⁶⁹Er ¹⁷¹Er	Erbium (68)	40 0.6	1000 10	0.9 0.5	20 10
¹⁴⁷Eu ¹⁴⁸Eu ¹⁴⁹Eu ¹⁵⁰Eu ¹⁵²Eu^m ¹⁵³Eu ¹⁵⁴Eu ¹⁵⁵Eu ¹⁵⁶Eu	Europium (63)	2 0.5 20 0.7 0.6 0.9 0.8 20 0.6	50 10 500 10 10 20 20 500 10	2 0.5 20 0.7 0.6 0.9 0.8 2 0.5	50 10 500 10 10 20 10 50 10
¹⁸F	Fluorine (9)	1	20	0.5	10
⁵²Fe (b) ⁵⁵Fe ⁵⁹Fe ⁶⁰Fe	Iron (26)	0.2 40 0.8 40	5 1000 20 1000	0.2 40 0.8 0.2	5 1000 20 5

TABLE I. A_lAND A₂ VALUES FOR RADIONUCLIDES (Continued)

Symbol of radionuclide	Element and atomic number	A₁(TBq)	A_l(Ci)	A₂ (TBq) (approx. ^a)	A₂ (Ci) (approx. ^a)
⁶⁷Ga ⁶⁸Ga ⁷²Ga	Gallium (31)	6 0.3 0.4	100 8 10	6 0.3 0.4	100 8 10
¹⁴⁶Gd (b) ¹⁴⁸Gd ¹⁵³Gd ¹⁵⁹Gd	Gadolinium (64)	0.4 3 10 4	10 80 200 100	0.4 3 x 10^-48 x 10^-3 5 0.5	10 100 10
⁶⁸Ge (b) ⁷¹Ge ⁷⁷Ge	Germanium (32)	0.3 40 0.3	8 1000 8	0.3 40 0.3	8 1000 8
¹⁷²Hf (b) ¹⁷⁵Hf ^18lHf ¹⁸²Hf	Hafnium (72)	0.5 3 2 4	10 80 50 100	0.3 3 0.9 3 x 10^-28 x 10^-1	8 80 20
¹⁹⁴Hg (b) ¹⁹⁵Hg^m ¹⁹⁷Hg^m ¹⁹⁷Hg ²⁰³Hg	Mercury (80)	1 5 10 10 4	20 100 200 200 100	1 5 0.9 10 0.9	20 100 20 200 20
¹⁶³Ho ¹⁶⁶Ho^m ¹⁶⁶Ho	Holmium (67)	40 0.6 0.3	1000 10 8	40 0.3 0.3	1000 8 8
¹²³I ¹²⁴I ¹²⁵I ¹²⁶I ¹²⁹I ¹³¹I ¹³²I ¹³³I ¹³⁴I ¹³⁵I	Iodine (53)	6 0.9 20 2 Unlimited 3 0.4 0.6 0.3 0.6	100 20 500 50 80 10 10 8 10	6 0.9 2 0.9 Unlimited 0.5 0.4 0.5 0.3 0.5	100 20 50 20 10 10 10 8 10

TABLE I. A_lAND A₂ VALUES FOR RADIONUCLIDES (Continued)

Symbol of radionuclide	Element and atomic number	A₁(TBq)	A_l(Ci)	A₂ (TBq) (approx. ^a)	A₂ (Ci) (approx. ^a)
¹¹¹In ¹¹³In^m ¹¹⁴In^m(b) ¹¹⁵In^m	Indium (49)	2 4 0.3 6	50 100 8 100	2 4 0.3 0.9	50 100 8 20
¹⁸⁹Ir ¹⁹⁰Ir ¹⁹²Ir ¹⁹³Ir^m ¹⁹⁴Ir	Iridium (77)	10 0.7 1 10 0.2	200 10 20 200 5	10 0.7 0.5 10 0.2	200 10 10 200 5
⁴⁰K ⁴²K ⁴³K	Potassium (19)	0.6 0.2 1	10 5 20	0.6 0.2 0.5	10 5 10
^8lKr ⁸⁵Kr^m ⁸⁵Kr ⁸⁷Kr	Krypton (36)	40 6 20 0.2	1000 100 500 5	40 6 10 0.2	1000 100 200 5
¹³⁷La ¹⁴⁰La	Lanthanum (57)	40 0.4	1000 10	2 0.4	50 10
LSA	Low specific	activity material	(see paragraph.	131 of Parent	Document)
¹⁷²Lu ¹⁷³Lu ¹⁷⁴Lu^m ¹⁷⁴Lu ¹⁷⁷Lu	Lutetium (71)	0.5 8 20 8 30	10 200 500 200 800	0.5 8 8 4 0.9	10 200 200 100 20
MFP	For mixed fission	products, use	formula for	mixtures or	Table II
²⁸Mg (b)	Magnesium (12)	0.2	5	0.2	5
⁵²Mn ⁵³Mn ⁵⁴Mn ⁵⁶Mn	Manganese (25)	0.3 Unlimited 1 0.2	8 20 5	0.3 Unlimited 1 0.2	8 20 5

TABLE I. A_lAND A₂ VALUES FOR RADIONUCLIDES (Continued)

Symbol of radionuclide	Element and atomic number	A₁(TBq)	A_l(Ci)	A₂ (TBq) (approx. ^a)	A₂ (Ci) (approx. ^a)
⁹³Mo ⁹⁹Mo	Molybdenum (42)	40 0.6	1000 10	7 0.5	100 10
¹³N	Nitrogen (7)	0.6	10	0.5	10
²²Na ²⁴Na	Sodium (11)	0.5 0.2	10 5	0.5 0.2	10 5
⁹²Nb^m ⁹³Nb^m ⁹⁴Nb ⁹⁵Nb ⁹⁷Nb	Niobium (41)	0.7 40 0.6 1 0.6	10 1000 10 20 10	0.7 6 0.6 1 0.5	10 10 10 20 10
¹⁴⁷Nd ¹⁴⁹Nd	Neodymium (60)	4 0.36	100 10	0.5 0.5	10 10
⁵⁹Ni ⁶³Ni ⁶⁵Ni	Nickel (28)	40 40 0.3	1000 1000 8	40 30 0.3	1000 800 8
²³⁵Np ²³⁶Np ²³⁷Np ²³⁹Np	Neptunium (93)	40 7 2 6	1000 100 50 100	40 1 x 10^-32 x 10^-2 2 x 10^-45 x 10^-3 0.5	1000 10
¹⁸⁵Os ¹⁹¹Os^m ¹⁹¹Os ¹⁹³Os ¹⁹⁴Os (b)	Osmium (76)	1 40 10 0.6 0.2	20 1000 200 10 5	1 40 0.9 0.5 0.2	20 1000 20 10 5
³²P ³³P	Phosphorus (15)	0.3 40	8 1000	0.3 0.9	8 20
²³⁰Pa ^23lPa ²³³Pa	Protactinium (91)	2 0.6 5	50 10 100	0.1 6 x 10^-51 x 10^-3 0.9	2 20

TABLE I. A_lAND A₂ VALUES FOR RADIONUCLIDES (Continued)

Symbol of radionuclide	Element and atomic number	A₁(TBq)	A_l(Ci)	A₂ (TBq) (approx. ^a)	A₂ (Ci) (approx. ^a)
²⁰¹Pb ²⁰²Pb ²⁰³Pb ²⁰⁵Pb ²¹⁰Pb (b) ²¹²Pb (b)	Lead (82)	1 40 3 Unlimited 0.6 0.3	20 1000 80 10 8	1 2 3 Unlimited 9 x 10^-32 x 10^-1 .3	20 50 80 8
¹⁰³Pd ¹⁰⁷Pd ¹⁰⁹Pd	Palladium (46)	40 Unlimited 0.6	1000 10	40 Unlimited 0.5	1000 10
¹⁴³Pm ¹⁴⁴Pm ¹⁴⁵Pm ¹⁴⁷Pm ¹⁴⁸Pm^m ¹⁴⁹Pm ¹⁵¹Pm	Promethium (61)	3 0.6 30 40 0.5 0.6 3	80 10 800 1000 10 10 80	3 0.6 7 0.9 0.5 0.5 0.5	80 10 100 20 10 10 10
²⁰⁸Po ²⁰⁹Po ²¹⁰Po	Polonium (84)	40 40 40	1000 1000 1000	2 x 10^-25 x 10^-1 2 x 10^-25 x 10^-1 2 x 10^-25 x 10^-1
¹⁴²Pr ¹⁴³Pr	Praseodymium (59)	0.2 4	5 100	0.2 0.5	5 10
¹⁸⁸Pt (b) ¹⁹¹Pt ¹⁹³Pt^m ¹⁹³Pt ¹⁹⁵Pt^m ¹⁹⁷Pt^m ¹⁹⁷Pt	Platinum (78)	0.6 3 40 40 10 10 20	10 80 1000 1000 200 200 500	0.6 3 9 40 2 0.9 0.5	10 80 200 1000 50 20 10

TABLE I. A_lAND A₂ VALUES FOR RADIONUCLIDES (Continued)

Symbol of radionuclide	Element and atomic number	A₁(TBq)	A_l(Ci)	A₂ (TBq) (approx. ^a)	A₂ (Ci) (approx. ^a)
²³⁶Pu ²³⁷Pu ²³⁸Pu ²³⁹Pu ²⁴⁰Pu ²⁴¹Pu ²⁴²Pu ²⁴⁴Pu (b)	Plutonium (94)	7 20 2 2 2 40 2 0.3	100 500 50 50 50 1000 50 8	7 x 10^{- 4} 20 2 x 10^-45 x 10^-3 2 x 10^-4 5 x 10^-3 2 x 10^-4 1 x 10^-22 x 10^-1 2 x 10^-45 x 10^-3 2 x 10^-45 x 10^-3	1 x 10^-2 500 5 x 10^-3
²²³Ra (b) ²²⁴Ra (b) ²²⁵Ra (b) ²²⁶Ra (b) ²²⁸Ra (b)	Radium (88)	0.6 0.3 0.6 0.3 0.6	10 8 10 8 10	3 x 10^-28 x 10^-1 6 x 10^-21 2 x 10^-25 x 10^-1 2 x 10^-25 x 10^-1 4 x 10^-2 1
⁸¹Rb ⁸³Rb ⁸⁴Rb ⁸⁶Rb ⁸⁷Rb Rb (natural)	Rubidium (37)	2 2 1 0.3 Unlimited Unlimited	50 50 20 8	0.9 2 0.9 0.3 Unlimited Unlimited	20 50 20 8
¹⁸³Re ¹⁸⁴Re^m ¹⁸⁴Re ¹⁸⁶Re ¹⁸⁷Re ¹⁸⁸Re ¹⁸⁹Re Re (natural)	Rhenium (75)	5 3 1 4 Unlimited 0.2 4 Unlimited	100 80 20 100 5 100	5 3 1 0.5 Unlimited 0.2 0.5 Unlimited	100 80 20 10 5 10
⁹⁹Rh ¹⁰¹Rh ¹⁰²Rh^m ¹⁰²Rh ¹⁰³Rh^m ¹⁰⁵Rh	Rhodium (45)	2 4 2 0.5 40 10	50 100 50 10 1000 200	2 4 0.9 0.5 40 0.9	50 100 20 10 1000 20
²²²Rn (b)	Radon (86)	0.2	5	4 x 10^-31 x 10^-1

TABLE I. A_lAND A₂ VALUES FOR RADIONUCLIDES (Continued)

Symbol of radionuclide	Element and atomic number	A₁(TBq)	A_l(Ci)	A₂(TBq) (approx. ^a)	A₂ (Ci) (approx. ^a)
⁹⁷Ru ¹⁰³Ru ¹⁰⁵Ru ¹⁰⁶Ru (b)	Ruthenium (44)	4 2 0.6 0.2	100 50 10 5	4 0.9 0.5 0.2	100 20 10 5
³⁵S	Sulfur (16)	40	1000	2	50
¹²²Sb ¹²⁴Sb ¹²⁵Sb ¹²⁶Sb	Antimony (51)	0.3 0.6 2 0.4	8 10 50 10	0.3 0.5 0.9 0.4	8 10 20 10
⁴⁴Sc ⁴⁶Sc ⁴⁷Sc ⁴⁸Sc	Scandium (21)	0.5 0.5 9 0.3	10 10 200 8	0.5 0.5 0.9 0.3	10 10 20 8
SCO	Surface	contaminated	objects (see parag.	144 of Parent	Document)
⁷⁵Se ⁷⁹Se	Selenium (34)	3 40	80 1000	3 2	80 50
³¹Si ³²Si	Silicon (14)	0.6 40	10 1000	0.5 0.2	10 5
¹⁴⁵Sm ¹⁴⁷Sm ¹⁵¹Sm ¹⁵³Sm	Samarium (62)	20 Unlimited 40 4	500 1000 100	20 4 0.5	500 Unlimited 100 10
¹¹³Sn (b) ¹¹⁷Sn^m ¹¹⁹Sn^m ¹²¹Sn^m ¹²⁵Sn ¹²⁶Sn (b)	Tin (50)	4 6 40 40 0.6 0.2 0.3	100 100 1000 1000 10 5 8	4 2 40 0.9 0.5 0.2 0.3	100 50 1000 20 10 5 8

TABLE I. A_lAND A₂ VALUES FOR RADIONUCLIDES (Continued)

Symbol of radionuclide	Element and atomic number	A₁(TBq)	A_l(Ci)	A₂ (TBq) (approx. ^a)	A₂ (Ci) (approx. ^a)
⁸²Sr (b) ⁸⁵Sr^m ⁸⁵Sr ⁸⁷Sr^m ⁸⁹Sr ⁹⁰Sr (b) ⁹¹Sr ⁹²Sr (b)	Strontium (38)	0.2 5 2 3 0.6 0.2 0.3 0.8	5 100 50 80 10 5 8 5	0.2 5 2 3 0.5 0.1 0.3 0.5	5 100 50 80 10 2 8 10
T (all forms)	Tritium (1)	40	1000	40	1000
¹⁷⁸Ta ¹⁷⁹Ta ¹⁸²Ta	Tantalum (73)	1 30 0.8	20 800 20	1 30 0.5	20 800 10
¹⁵⁷Tb ¹⁵⁸Tb ¹⁶⁰Tb	Terbium (65)	40 1 0.9	1000 20 20	10 0.7 0.5	200 10 10
⁹⁵Tc^m ⁹⁶Tc^m(b) ⁹⁶Tc ⁹⁷Tc^m ⁹⁷Tc ⁹⁸Tc ⁹⁹Tc^m ⁹⁹Tc	Technetium (43)	2 0.4 0.4 40 Unlimited 0.7 8 40	50 10 10 1000 10 200 1000	2 0.4 0.4 40 Unlimited 0.7 8 0.9	50 10 10 1000 10 20 20
¹¹⁸Te (b) ¹²¹Te^m ¹²¹Te ¹²³Te^m ¹²⁵Te^m ¹²⁷Te^m(b) ¹²⁷Te ¹²⁹Te^m(b) ¹²⁹Te ¹³¹Te^m ¹³²Te (b)	Tellurium (52)	0.2 5 2 7 30 20 20 0.6 0.6 0.7 0.4	5 100 50 100 800 500 50 10 10 10 10	0.2 5 2 7 9 0.5 0.5 0.5 0.5 0.5 0.4	5 100 50 100 200 10 10 10 10 10 10

TABLE I. A_lAND A₂ VALUES FOR RADIONUCLIDES (Continued)

Symbol of radionuclide	Element and atomic number	A₁(TBq)	A_l(Ci)	A₂ (TBq) (approx. ^a)	A₂ (Ci) (approx. ^a)
²²⁷Th ²²⁸Th (b) ^229Th ²³⁰Th ²³¹Th ²³²Th ^234Th (b) Th (natural)	Thorium (90)	9 0.3 0.3 2 40 Unlimited 0.2 Unlimited	200 8 8 50 1000 5	1 x 10^-22 x 10^-1 4 x 10^-41 x 10^-2 3 x 10^-58 x 10^-4 2 x 10^-45 x 10^-3 0.9 Unlimited 0.2 Unlimited	20 5
⁴⁴Ti (b) ²⁰⁰Ti ²⁰¹Ti ²⁰²Ti ²⁰⁴Ti	Titanium (22) Thallium (81)	0.5 0.8 10 2 4	10 20 200 50 100	0.2 0.8 10 2 0.5	5 20 200 50 10
¹⁶⁷Tm ¹⁶⁸Tm ¹⁷⁰Tm ¹⁷¹Tm	Thulium (69)	7 0.8 4 40	100 20 100 1000	7 0.8 0.5 10	100 20 10 200
²³⁰U ²³²U ²³³U ²³⁴U ²³⁵U ²³⁶U U (natural) U (enriched 5% or less) U (enriched more than 5%) U (depleted)	Uranium (92)	40 3 10 10 Unlimited ^c 10 Unlimited Unlimited Unlimited ^c 10 Unlimited	1000 80 200 200 200 200	1 x 10^-22 x 10^-1 3 x 10^-48 x 10^-3 1 x 10^-32 x 10^-2 1 x 10^-32 x 10^-2 Unlimited ^c 1 x 10^-32 x 10^-2 Unlimited Unlimited ^d Unlimited ^c,d 1 x 10^-3 ^d2 x 10^-2 Unlimited ^d
⁴⁸V ⁴⁹V	Vanadium (23)	0.3 40	8 1000	0.3 40	8 1000

TABLE I. A_lAND A₂ VALUES FOR RADIONUCLIDES (Continued)

Symbol of radionuclide	Element and atomic number	A₁(TBq)	A_l(Ci)	A₂ (TBq) (approx. ^a)	A₂ (Ci) (approx. ^a)
¹⁷⁸W(b) ¹⁸¹W ¹⁸⁵W ¹⁸⁷W ¹⁸⁸W (b)	Tungsten (74)	1 30 40 2 0.2	20 800 1000 50 5	1 30 0.9 0.2	20 800 20 10 5
¹²²Xe (b) ¹²³Xe ¹²⁷Xe ¹³¹Xe^m ¹³³Xe ¹³⁵Xe	Xenon (54)	0.2 0.2 4 40 20 4	5 5 100 1000 500 100	0.2 0.2 4 40 20 4	5 5 100 1000 500 100
⁸⁷Y ⁸⁸Y ⁹⁰Y ⁹¹Y^m ⁹¹Y ⁹²Y ⁹³Y	Yttrium (39)	2 0.4 0.2 2 0.3 0.2 0.2	50 10 5 50 8 5 5	2 0.4 0.2 2 0.3 0.2 0.2	50 10 5 50 8 5 5
^l69Yb ¹⁷⁵Yb	Ytterbium (70)	3 30	80 800	3 0.9	80 20
⁶⁵Zn ⁶⁹Zn^m(b) ⁶⁹Zn	Zinc (30)	2 2 4	50 50 100	2 0.5 0.5	50 10 10
⁸⁸Zr ⁹³Zr ⁹⁵Zr ⁹⁷Zr	Zirconium (40)	3 40 1 0.3	80 1000 20 8	3 0.2 0.9 0.3	80 5 20 8

^a The curie values quoted are obtained by rounding down from the TBq figure after conversion to Ci.
This ensures that the magnitude of A_l or A₂ in Ci is always less than that in Tbq.

^b A_l and/or A₂ value limited by daughter product decay.
^c A_l and A₂ are unlimited for radiation control purposes only. For nuclear criticality safety this material is subject to the control placed on fissile material.

^d These values do not apply to reprocessed uranium.
Alternatively, an A₂ value for mixtures may be determined as follows:

where is f (i) is the fraction of activity of nuclide i in the mixture and A₂ (i) is the appropriate A₂ value for nuclide i.

5. 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 304. 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 or beta/gamma emitters, respectively.

6. For individual radionuclides or for mixtures of radionuclides for which relevant data are not available, the values shown in Table II shall be used.

TABLE II. GENERAL VALUES FOR A₁ AND A₂

Contents A₁ A₂
TBq (Ci)^a TBq (Ci)^a

Only beta or gamma emitting 0.2 (5) 0.02 (0.5)
nuclides are known to be
present

Alpha emitting nuclides are 0.1 (2) 2 x 10^-5(5 x 10^-4)
known to be present or no relevant data are available
^a The curie values quoted in parentheses are approximate values and are not higher than the TBq values

| TOC | Change | Preface | Chapter1 | Chapter2 | Chapter3 | Chapter4 | Chapter5 | Chapter6 | Chapter7 | Chapter8 | Chapter9 | AppendixA | AppendixB | AppendixC | AppendixD | AppendixE | AppendixF | AppendixG | AppendixH | AppendixI | AppendixJ | AppendixK | ALL |

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