For a given radionuclide, the A1 or A2 value is defined as the maximum activity permitted in a Type A package. The A1 value applies for special form radioactive material, while the A2 value applies for radioactive material in other than special form. (See section 38.3 Definitions.)
I. Single Radionuclides
(1) For a single radionuclide of known identity, the values of A1 and A2 are taken from Table 1 if listed there. The values A1 and A2 in Table 1 are also applicable for the radionuclide contained in (α,n) or (γ,n) neutron sources.
(2) For any single radionuclide whose identity is known but which is not listed in Table 1, the value of A1 and A2 are determined according to the following procedure:
(2) (a) If the radionuclide emits only one type of radiation, A1 is determined according to the following method. For radionuclides emitting different kinds of radiation, A1 is the most restrictive value of those determined for each kind of radiation. However, in either case, A1 is restricted to a maximum of 1000 curies (37 TBq). If a parent nuclide decays into a shorter lived daughter with a half-life not greater than 10 days, A1 is calculated for both the parent and the daughter, and the more limiting of the two values is assigned to the parent nuclide.
(1) For gamma emitters, A
1
is determined by the expression:
A
1
=
9
curies
Γ
Where Γ is the gamma-ray constant, corresponding to the dose in roentgens per curie-hour at 1 meter, and the number 9 results from the choice of 1 rem per hour at a distance of 3 meters as the reference dose-equivalent rate.
(2) For x-ray emitters, A1 is determined by the atomic number of the nuclide:
for Z ≤ 55, A
1
= 1000 Ci (37 TBq); and
for Z > 55, A
1
= 200 Ci (7.4 TBq)
where Z is the atomic number of the nuclide.
(3) For beta emitters, A1 is determined by the maximum beta energy (E max) according to Table 2; and
(4) For alpha emitters, A1 is determined by the expression:
A1 = 1000 A3
where A3 is the value listed in Table 3;
(2) (b) A2 is the more restrictive of the following two values:
(2) (1) the corresponding A1; and
(2) (2) the value A3 obtained from Table 3.
(3) For any single radionuclide whose identity is unknown, the value of A1 is taken to be 2 Ci (74 GBq) and the value of A2 is taken to be 0.002 Ci (74 MBq). However, if the atomic number of the radionuclide is known to be less than 82, the value of A1 is taken to be 10 Ci (370 GBq) and the value of A2 is taken to be 0.4 Ci (14.8 GBq).
II. Mixtures of Radionuclides, Including Radioactive Decay Chains
1. For mixed fission products, the activity limit may be assuned if a detailed analysis of the mixture is not carried out,
A1 = 10 Ci (370 GBq)
A2 = 0.4 Ci (14.8 GBq)
2 A single radioactive decay chain is considered to be a single radionuclide when the radionuclides are present in their naturally occurring proportions and no daughter nuclide has a half-life either longer than 10 days or longer than that of the parent nuclide. The activity to be taken into account and the A1 or A2 value from Table 1 to be applied are those corresponding to the parent nuclide of that chain. When calculating A1 or A2 values, radiation emitted by daughters must be considered. However, 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 daughter nuclides are considered to be mixtures of different nuclides.
3. In the case of a mixture of different radionuclides, where the identity and activity of each radionuclide are known, the permissible activity of each radionuclide R1, R2. . . Rn is such that F1 + F2 +. . . Fn is not greater than unity, where:
F
1
=
Total activity of R1
A1(R1)
F
2
=
Total activity of R2
A1(R2)
F
n
=
Total activity of Rn and
A1(Rn)
A1 (R1, R2. . . Rn is the value of A1 or A2 as appropriate for the nuclide R1, R2. . . Rn.
4. When the identity of each radionuclide is known but the individual activities of some of the radionuclides are not known, the formula given in paragraph 3. is applied to establish the values of A1 or A2 as appropriate. All the radionuclides whose individual activities are not known their total activity will however, be known) are classed in a single group and the most restrictive value of A1 and A2applicable to any one of them is used as the value of A1 or A2 in the denominator of the fraction.
5. Where the identity of each radionuclide is known but the individual activity of none of the radionuclides is known, the most restrictive value of A1 or A2 applicable to any one of the radionuclides present is adopted as the applicable value.
6. When the identity of none of the nuclides is known, the value of A1 is taken to be 2 Ci (74 GBq) and the value of A2 is taken to be 0.002 Ci (74 MBq). However, if alpha emitters are known to be absent, the value of A2 is taken to be 0.4 Ci (14.8 GBq).
TABLE 1
A1 AND A2 VALUES FOR RADIONUCLIDES
(See footnotes at end of Table)
Symbol of Radionuclide
Element and Atomic Number
A1 (Ci)
A2 (Ci)
Specific Activity (Ci/g)
Ac-227
Actinium (89)
1000
0.003
7.2 E + 01
Ac-228
10
4
2.2 E + 06
Ag-105
Silver (47)
40
40
3.9 E + 07
Ag-110m
7
7
4.7 E + 03
Ag-111
100
20
1.5 E + 05
Am-241
Americium (95)
8
0.008
3.2
Am-243
8
0.008
1.9 E − 01
Ar-37 (compressed or Uncompressed)*
Argon (18)
1000
1000
1.0 E + 05
Ar-41 (uncompressed)*
20
20
4.3 E + 07
Ar–41 (compressed)*
1
1
4.3 E.+ 07
As–73
Arsenic (33)
1000
400
2.4 E + 04
As–74
20
20
1.0 E + 05
As–76
10
10
1.6 E + 06
As–77
300
20
1.1 E + 06
At–211
Astatine (85)
200
7
2.1 E + 06
Au–193
Gold (79)
200
200
9.3 E + 05
Au–196
30
30
1.2 E + 05
Au–198
40
20
2.5 E + 05
Au–199
200
25
2.1 E + 05
Ba–131
Barium (56)
40
40
8.7 E + 04
Ba–133
40
40
4.0 E + 03
Ba–140
20
20
7.3 E + 04
Be–7
Beryllium (4)
300
300
3.5 E + 05
Bi–206
Bismuth (83)
5
5
9.9 E + 04
Bi–207
10
10
2.2 E + 02
Bi–210 (RaE)
100
4
1.2 E + 05
Bi–212
6
6
1.5 E + 07
Bk–249
Berkelium (97)
1000
1
1.9 E + 03
Br–77
Bromine (35)
70
25
7.1 E + 03
Br–82
6
6
1.1 E + 06
C–11
Carbon (6)
20
20
8.4 E + 08
C–14
1000
60
4.6
Ca–45
Calcium (20)
1000
25
1.9 E + 04
Ca–47
20
20
5.9 E + 05
Cd–109
Cadmium (48)
1000
70
2.6 E + 03
Cd–115m
30
30
2.6 E + 04
Cd–115
80
20
5.1 E + 05
Ce–139
Cerium (58)
100
100
6.5 E + 03
Ce–141
300
25
2.8 E + 04
Ce–143
60
20
6.6 E + 05
Ce–144
10
7
3.2 E + 03
Cf–249
Californium (98)
2
0.002
3.1
Cf–250
7
0.007
1.3 E + 02
Cf–252
2
0.009
6.5 E + 02
Cl–36
Chlorine (17)
300
10
3.2 E.− 02
Cl–38
10
10
1.3 E + 08
Cm–242
Curium (96)
200
0.2
3.3 E + 03
Cm–243
9
0.009
4.2 E + 01
Cm–244
10
0.01
8.2 E + 01
Cm–245
6
0.006
1.0 E − 01
Cm–246
6
0.006
3.6 E − 01
Co–56
Cobalt (27)
5
5
3.0 E + 04
Co–57
90
90
8.5 E + 03
Co–58m
1000
1000
5.9 E + 06
Co–58
20
20
3.1 E + 05
Co–60
7
7
1.1 E + 03
Cr–51
Chromium (24)
600
600
9.2 E + 04
Cs–129
Cesium (55)
40
40
7.6 E + 05
Cs–131
1000
1000
1.1 E + 05
Cs–134m
1000
10
7.4 E + 06
Cs–134
10
10
1.2 E + 03
Cs–135
1000
25
8.8 E − 04
Cs–136
7
7
7.4 E + 04
Cs–137
30
10
9.8 E + 01
Cu–64
Copper (29)
80
25
3.8 E + 06
Cu–67
200
25
7.9 E + 05
Dy–165
Dysprosium (66)
100
20
8.2 E + 06
Dy–166
1000
200
2.3 E + 05
Er–169
Erbium (68)
1000
25
8.2 E + 04
Er–171
50
20
2.4 E + 06
Eu–152m
Europium (63)
30
30
2.2 E + 06
Eu–152
20
10
1.9 E + 02
Eu–154
10
5
1.5 E + 02
Eu–155
400
60
1.4 E + 03
F–18
Fluorine (9)
20
20
9.3 E + 07
Fe–52
Iron (26)
5
5
7.3 E + 06
Fe–55
1000
1000
2.2 E + 03
Fe–59
10
10
4.9 E + 04
Ga–67
Gallium (31)
100
100
6.0 E + 03
Ga–68
20
20
4.0 E + 07
Ga–72
7
7
3.1 E + 06
Gd–153
Gadolinium (64)
200
100
3.6 E + 03
Gd–159
300
20
1.1 E + 06
Ge–68
Gernanium (32)
20
10
7.0 E + 03
Ge–71
1000
1000
1.6 E + 05
H–3
Hydrogen (1)
See Tritium
Hf–181
Hafnium (72)
30
25
1.6 E + 04
Hg–197m
Mercury (80)
200
200
6.6 E + 05
Hg–197
200
200
2.5 E + 05
Hg–203
80
25
1.4 E + 04
Ho–166
Holmium (67)
30
30
6.9 E + 05
I–123
Iodine (53)
50
50
6.9 E + 04
I–125
1000
70
1.7 E + 04
I–126
40
10
7.8 E + 04
I–129
1000
2
1.6 E − 04
I–131
40
1
1.2 E + 05
I–132
7
7
1.1 E + 07
I–133
30
10
1.1 E + 06
I–134
8
8
2.7 E + 07
I–135
10
10
3.5 E + 06
In–111
Indium (49)
30
25
4.2 E + 05
In–113m
60
60
1.6 E + 07
In–114m
30
20
2.3 E + 04
In–115m
100
20
6.1 E + 06
Ir–190
Iridium (77)
10
10
6.2 E + 04
Ir–192
20
10
9.1 E + 03
Ir–194
10
10
8.5 E + 05
K–42
Potassium (19)
10
10
6.0 E + 06
K–43
20
10
3.3 E + 06
Kr–85m (uncompressed)*
Krypton (36)
100
100
8.4 E + 06
Kr–85m (compressed)*
3
3
8.4 E + 06
Kr–85 (uncompressed)*
1000
1000
4.0 E + 02
Kr–85 (compressed)*
5
5
4.0 E + 02
Kr–87 (uncompressed)*
20
20
2.8 E + 07
Kr–87 (compressed)*
0.6
0.6
2.8 E + 07
La–140
Lanthanum (57)
30
30
5.6 E + 05
Lu–177
Lutetium (71)
300
25
1.1 E + 05
MFP
Mixed Fission Products
10
0.4
–––
Mg–28
Magnesium (12)
6
6
5.2 E + 06
Mn–52
Manganese (25)
5
5
4.4 E + 05
Mn–54
20
20
8.3 E + 03
Mn–56
5
5
2.2 E + 07
Mo–99
Molybdenum (42)
100
20
4.7 E + 05
N–13
Nitrogen (7)
20
10
1.5 E + 09
Na–22
Sodium (11)
8
8
6.3 E + 03
Na–24
5
5
8.7 E + 06
Nb–93m
Niobium (41)
1000
200
4.1 E + 02
Nb–95
20
20
3.9 E + 07
Nb–97
20
20
2.6 E + 07
Nd–147
Neodymium (60)
100
20
8.0 E + 04
Nd–149
30
20
1.1 E + 07
Ni–59
Nickel (28)
1000
900
8.1 E − 02
Ni–63
1000
100
4.6 E + 01
Ni–65
10
10
1.9 E + 07
Np–237
Neptunium (93)
5
0.005
6.9 E − 04
Np–239
200
25
2.3 E + 05
Os–185
Osmium (76)
20
20
7.3 E + 03
Os–191
600
200
4.6 E + 04
Os–191m
200
200
1.2 E + 06
Os–193
100
20
5.3 E + 05
P–32
Phosphorus (15)
30
30
2.9 E + 05
Pa–230
Protactinium (91)
20
0.8
3.2 E + 04
Pa–231
2
0.002
4.5 E − 02
Pa–233
100
100
2.1 E + 04
Pb–201
Lead (82)
20
20
1.7 E + 06
Pb–210
100
0.2
8.8 E + 01
Pb–212
6
5
1.4 E + 06
Pd–103
Palladium (46)
1000
700
7.5 E + 04
Pd–109
100
20
2.1 E + 06
Pm–147
Promethium (61)
1000
25
9.4 E + 02
Pm–149
100
20
4.2 E + 05
Po–210
Polonium (84)
200
0.2
4.5 E + 03
Pr–142
Praseodymium (59)
10
10
1.2 E + 06
Pr–143
300
20
6.6 E + 04
Pt–191
Platinum (78)
100
100
2.3 E + 05
Pt–193m
200
200
2.0 E + 05
Pt–197m
300
20
1.2 E + 07
Pt–197
300
20
8.8 E + 05
Pu–238
Plutonium (94)
3
0.003
1.7 E + 01
Pu–239
2
0.002
6.2 E − 02
Pu–240
2
0.002
2.3 E − 01
Pu–241
1000
0.1
1.1 E + 02
Pu–242
3
0.003
3.9 E − 03
Ra–223
Radium (88)
50
0.2
5.0 E + 04
Ra–224
6
0.5
1.6 E + 05
Ra–226
10
0.05
1.0
Ra–228
10
0.05
2.3 E + 02
Rb–81
Rubidium (37)
30
24
8.2 E + 04
Rb–86
30
30
8.1 E + 04
Rb–87
Unlimited
Unlimited
6.6 E − 08
Rb (natural)
Unlimited
Unlimited
1.8 E − 08
Re–186
Rhenium (75)
100
20
1.9 E + 05
Re–187
Unlimited
Unlimited
3.8 E − 08
Re (natural)
Unlimited
Unlimited
2.4 E − 08
Rh–103m
Rhodium (45)
1000
1000
3.2 E + 07
Rh–105
200
25
8.2 E + 05
Rn–222
Radon (86)
10
2
1.5 E + 05
Ru–97
Ruthenium (44)
80
80
5.5 E + 05
Ru–103
30
25
3.2 E + 04
Ru–105
20
20
6.6 E + 06
Ru–106
10
7
3.4 E + 03
S–35
Sulphur (16)
1000
60
4.3 E + 04
Sb–122
Antimony (51)
30
30
3.9 E + 05
Sb–124
5
5
1.8 E + 04
Sb–125
40
25
1.4 E + 03
Sc–46
Scandium (21)
8
8
3.4 E + 04
Sc–47
200
20
8.2 E + 05
Sc–48
5
5
1.5 E + 06
Se–75
Selenium (34)
40
40
1.4 E + 04
Si–31
Silicon (14)
100
20
3.9 E + 07
Sm–147
Samarium (62)
Unlimited
Unlimited
2.0 E − 08
Sm–151
1000
90
2.6 E + 01
Sm–153
300
20
4.4 E + 05
Sn–113
Tin (50)
60
60
1.0 E + 04
Sn–119m
100
100
4.4 E + 03
Sn–125
10
10
1.1 E + 05
Sr–85m
Strontium (38)
80
80
3.2 E + 07
Sr–85
30
30
2.4 E + 04
Sr–89
100
10
2.9 E + 04
Sr–90
10
0.4
1.5 E + 02
Sr–91
10
10
3.6 E + 06
Sr–92
10
10
1.3 E + 07
T (uncompressed)*
Tritium (1)
1000
1000
9.7 E + 03
T (compressed)*
1000
1000
9.7 E + 03
T (activated luminous paint)
1000
1000
9.7 E + 03
T (absorbed on solid carrier)
1000
1000
9.7 E + 03
T (tritiated water)
1000
1000
9.7 E + 03
T (other forms)
20
20
9.7 E + 03
Ta–182
Tantalum (73)
20
20
6.2 E + 03
Tb–182
Terbium (65)
20
10
1.1 E + 05
Tc–96m
Technetium (43)
1000
1000
3.8 E + 07
Tc–96
6
6
3.2 E + 05
Tc–97m
1000
200
1.5 E + 04
Tc–97
1000
400
1.4 E + 04
Tc–99m
100
100
5.2 E + 06
Tc–99
1000
25
1.7 E − 02
Te–125m
Tellurium (52)
1000
100
1.8 E + 04
Te–127m
300
20
4.0 E + 04
Te–127
300
20
2.6 E + 06
Te–129m
30
10
2.5 E + 04
Te–129
100
20
2.0 E + 07
Te–131m
10
10
8.0 E + 05
Te–132
7
7
3.1 E + 05
Th–227
Thorium (90)
200
0.2
3.2 E + 04
Th–228
6
0.008
8.3 E + 02
Th–230
3
0.003
1.9 E − 02
Th–231
1000
25
5.3 E + 05
Th–232
Unlimited
Unlimited
1.1 E − 07
Th–234
10
10
2.3 E + 04
Th (natural)
Unlimited
Unlimited
2.2 E − 07
Th (irradiated)**
–––
–––
–––
Tl–200
Thallium (81)
20
20
5.8 E + 05
Tl–201
200
200
2.2 E + 05
Tl–202
40
40
5.4 E + 04
Tl–204
300
10
4.3 E + 02
Tm–170
Thulium (69)
300
10
6.0 E + 03
Tm–171
1000
100
1.1 E + 03
U–230
Uranium (92)
100
0.1
2.7 E + 04
U–232
30
0.03
2.1 E + 01
U–233
100
0.1
9.5 E − 03
U–234
100
0.1
6.2 E − 03
U–235
100
0.2
2.1 E − 06
U–236
200
0.2
6.3 E − 05
U–238
Unlimited
Unlimited
3.3 E − 07
U (natural)
Unlimited
Unlimited
(see Table 4)
U (enriched) < 20 percent
Unlimited
Unlimited
(see Table 4)
U (enriched) 20 percent or greater
Unlimited
Unlimited
(see Table 4)
U (depleted)
Unlimited
Unlimited
(see Table 4)
U (irradiated)***
–––
–––
–––
V–48
Vanadium (23)
6
6
1.7 E + 05
W–181
Tungsten (74)
200
100
5.0 E + 03
W–185
1000
25
9.7 E + 03
W–187
40
20
7.0 E + 05
Xe–127 (uncompressed)*
Xenon (54)
70
70
2.8 E + 04
Xe–127 (compressed)*
5
5
2.8 E + 04
Xe–131m (compressed)*
10
10
1.0 E + 05
Xe–131m
100
100
1.0 E + 05
Xe–133 (uncompressed)*
1000
1000
1.9 E + 05
Xe–133 (compressed)*
5
5
1.9 E + 05
Xe–135 (uncompressed)*
70
70
2.5 E + 06
Xe–135 (compressed)*
2
2
2.5 E + 06
Y–87
Yttrium (39)
20
20
4.5 E + 05
Y–90
10
10
5.4 E + 05
Y–91m
30
30
4.1 E + 07
Y–91
30
30
2.5 E + 04
Y–92
10
10
9.5 E + 06
Y–93
10
10
3.2 E + 06
Yb–169
Ytterbium (70)
80
80
2.3 E + 05
Yb–175
400
25
1.8 E + 05
Zn–65
Zinc (30)
30
30
8.0 E + 03
Zn–69m
40
20
3.3 E + 06
Zn–69
300
20
5.3 E + 07
Zr–93
Zirconium (40)
1000
200
3.5 E − 03
Zr–95
20
20
2.1 E + 04
Zr–97
20
20
2.0 E + 06
*
For the purpose of Table 1, compressed gas means a gas at a pressure which exceeds the ambient atmospheric pressure at the location where the containment system was closed.
**
The value of A1 and A 2 must be calculated in accordance with the procedure specified in paragraph II 3. of this Appendix, taking into account the activity of the fission products and of the uranium–233 in addition to that of the thorium.
***
The values of A1 and A 2 must be calculated in accordance with the procedure specified in paragraph II 3. of this Appendix, taking into account the activity of the fission products and plutonium isotopes in addition to that of the uranium.
TABLE 2
RELATIONSHIP BETWEEN A1 AND E MAX FOR BETA EMITTERS
E max (McV)
A1 (Ci)
> 0.5
1000
0.5 – > 1.0
300
1.0 – > 1.5
100
1.5 – > 2.0
30
≥ 2.0
10
TABLE 3
RELATIONSHIP BETWEEN A3 AND THE ATOMIC NUMBER OF THE RADIONUCLIDE
Atomic Number
Half-life less than 1000 days
A3 Half-life days to 10 years
Half-life greater than 10 years
1 to 81
3 Ci
0.05 Ci
3 Ci
82 and above
0.002 Ci
0.002 Ci
3 Ci
TABLE 4
ACTIVITY-MASS RELATIONSHIPS FOR URANIUM/THORIUM
Thorium and Uranium Enrichment*wt % U-235 present
Specific Activity
Ci/g
g/Ci
0.45
5.0 × 10−7
2.0 × 10
0.72 (natural)
7.06 × 10−7
1.42 × 10
1.0
7.6 × 10−7
1.3 × 10
1.5
1.0 × 10−6
1.0 × 10
5.0
2.7 × 10−6
3.7 × 10
10.0
4.8 × 10−6
2.1 × 10
20.0
1.0 × 10−5
1.0 × 10
35.0
2.0 × 10−5
5.0 × 10
50.0
2.5 × 10−5
4.0 × 10
90.0
5.8 × 10−6
1.7 × 10
93.0
7.0 × 10−6
1.4 × 10
95.0
9.1 × 10−6
1.1 × 10
Natural Thorium
2.2 × 10−7
4.6 × 10
*
The figures for uranium include representative values for the activity of the uranium-234 which is concentrated during the enrichment process. The activity for thorium includes the equilibrium concentration of thorium-228.
