Chart of 211 Radioactive Poisons
in 10-Year Old CANDU Spent Fuel

The following chart identifies 211 radioactive poisons which are present in every ten-year old irradiated CANDU fuel bundle. The list is not complete.

These data, compiled from AECL-9881, refer to the radioactive contents of an irradiated fuel bundle from the Bruce A reactors.

The origin of each radioactive poison is also indicated in the chart:

• F.P. indicates ''Fission Products'': these are the broken pieces of atoms which were split or fissioned in the reactor to produce energy [fission products are also produced when an atomic bomb explodes].

• F.I.A.P. indicates ''Fuel Impurity Activation Products'': during fission, impurities in the fuel become radioactive by absorbing neutrons.

• Z.A.P. indicates ''Zircaloy-4 Activation Products'': elements in the zirconium sheath also become radioactive by absorbing neutrons.

• ''Actinides'' refer to the radioactive decay products of uranium and the trans-uranium (heavier-than-uranium) elements created during fission, when uranium atoms absorb one or more neutrons without fissioning.

The radioactivity of each poison is only roughly indicated:

• a single yen-sign   ¥   indicates the presence of a particular radioactive poison;

• a triple yen-sign   ¥ ¥ ¥   indicates the presence of over a million becquerels of that radioactive poison
  • per kg of uranium fuel (for FP, FIAP, and Actinides) or
    
  • per kg of zirconium alloy (for ZAP).

The list is organized according to the electric charge of the nucleus (the so-called "atomic number [Z]"), from the smallest charge (Hydrogen-3, also known as "tritium") to the largest charge (Californium-252). This is consistent with the order of the elements in the periodic table.

Within each chemical species, the radioactive varieties (called "isotopes" or "nuclides") are organized according to the mass of the nucleus, indicated by the accompanying number in the chart, called the "mass number [A]".

Standard Chemical Symbol	Common Name of element	Atomic Mass Number	F.P. Fission Product	F.I.A.P. Activation Product	Z.A.P. Activation Product	Actinide (includes progeny)
H (T)	Hydrogen (Tritium)	3	¥ ¥ ¥	¥	¥
Be	Beryllium	10		¥	¥
C	Carbon	14		¥ ¥ ¥	¥ ¥ ¥
Si	Silicon	32		¥	¥
P	Phosphorus	32		¥	¥
S	Sulphur	35		¥
Cl	Chlorine	36		¥
Ar Ar	Argon Argon	39 42		¥ ¥	¥ ¥
K K	Potassium Potassium	40 42		¥	¥
Ca Ca	Calcium Calcium	41 45		¥	¥
Sc	Scandium	46		¥
Standard Chemical Symbol	Common Name of element	Atomic Mass Number	F.P. Fission Product	F.I.A.P. Activation Product	Z.A.P. Activation Product	Actinide (includes progeny)
V	Vanadium	50			¥
Mn	Manganese	54		¥	¥ ¥ ¥
Fe Fe	Iron Iron	55 59		¥ ¥ ¥	¥ ¥ ¥ ¥
Co Co	Cobalt Cobalt	58 60		¥ ¥ ¥ ¥	¥ ¥ ¥ ¥
Ni Ni	Nickel Nickel	59 63		¥ ¥ ¥ ¥	¥ ¥ ¥ ¥ ¥ ¥
Zn	Zinc	65		¥	¥
Se	Selenium	79	¥ ¥ ¥
Kr Kr	Krypton Krypton	81 85	¥ ¥ ¥ ¥
Rb	Rubidium	87	¥
Sr Sr	Strontium Strontium	89 90	¥ ¥ ¥ ¥	¥	¥ ¥
Y Y	Yttrium Yttrium	90 91	¥ ¥ ¥ ¥	¥	¥ ¥
Zr Zr	Zirconium Zirconium	93 95	¥ ¥ ¥ ¥	¥ ¥	¥ ¥ ¥ ¥
Standard Chemical Symbol	Common Name of element	Atomic Mass Number	F.P. Fission Product	F.I.A.P. Activation Product	Z.A.P. Activation Product	Actinide (includes progeny)
Nb Nb Nb Nb Nb	Niobium Niobium Niobium Niobium Niobium	92 93m 94 95 95m	¥ ¥ ¥ ¥ ¥ ¥	¥ ¥ ¥	¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥
Mo	Molybdenum	93		¥	¥
Tc	Technetium	99	¥ ¥ ¥	¥	¥
Ru Ru	Ruthenium Ruthenium	103 106	¥ ¥ ¥ ¥
Rh Rh	Rhodium Rhodium	103m 106	¥ ¥ ¥ ¥
Pd	Palladium	107	¥ ¥ ¥
Ag Ag Ag Ag Ag	Silver Silver Silver Silver Silver	108 108m 109m 110 110m	¥ ¥ ¥ ¥ ¥	¥ ¥ ¥ ¥ ¥ ¥ ¥	¥ ¥ ¥ ¥ ¥
Cd Cd Cd Cd	Cadmium Cadmium Cadmium Cadmium	109 113 113m 115	¥ ¥ ¥ ¥ ¥ ¥	¥	¥ ¥ ¥
Standard Chemical Symbol	Common Name of element	Atomic Mass Number	F.P. Fission Product	F.I.A.P. Activation Product	Z.A.P. Activation Product	Actinide (includes progeny)
In In In In	Indium Indium Indium Indium	113m 114 114m 115	¥	¥	¥ ¥ ¥ ¥
Sn Sn Sn Sn Sn Sn Sn	Tin Tin Tin Tin Tin Tin Tin	113 117m 119m 121m 123 125 126	¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥	¥	¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥
Sb Sb Sb Sb	Antimony Antimony Antimony Antimony	124 125 126 126m	¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥		¥ ¥ ¥ ¥ ¥
Te Te Te Te Te	Tellurium Tellurium Tellurium Tellurium Tellurium	123 123m 125m 127 127m	¥ ¥ ¥ ¥ ¥ ¥ ¥		¥ ¥ ¥ ¥ ¥ ¥ ¥
I	Iodine	129	¥		¥
Standard Chemical Symbol	Common Name of element	Atomic Mass Number	F.P. Fission Product	F.I.A.P. Activation Product	Z.A.P. Activation Product	Actinide (includes progeny)
Cs Cs Cs	Cesium Cesium Cesium	134 135 137	¥ ¥ ¥ ¥ ¥ ¥ ¥
Ba	Barium	137m	¥ ¥ ¥
La	Lanthanum	138	¥
Ce Ce	Cerium Cerium	142 144	¥ ¥ ¥ ¥
Pr Pr	Praseodymium Praseodymium	144 144m	¥ ¥ ¥ ¥ ¥ ¥
Nd	Neodymium	144	¥
Pm	Promethium	147	¥ ¥ ¥
Sm Sm Sm Sm	Samarium Samarium Samarium Samarium	147 148 149 151	¥ ¥ ¥ ¥ ¥ ¥	¥
Eu Eu Eu	Europium Europium Europium	152 154 155	¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥	¥ ¥ ¥
Standard Chemical Symbol	Common Name of element	Atomic Mass Number	F.P. Fission Product	F.I.A.P. Activation Product	Z.A.P. Activation Product	Actinide (includes progeny)
Gd Gd	Gadolinium Gadolinium	152 153	¥ ¥	¥ ¥
Tb Tb	Terbium Terbium	157 160		¥ ¥
Dy	Dysprosium	159		¥
Ho	Holmium	166m	¥	¥
Tm Tm	Thulium Thulium	170 171		¥ ¥
Lu Lu Lu	Lutetium Lutetium Lutetium	176 176 176			¥ ¥ ¥
Hf Hf Hf	Hafnium Hafnium Hafnium	175 181 182			¥ ¥ ¥
Ta Ta	Tantalum Tantalum	180 182			¥ ¥
Standard Chemical Symbol	Common Name of element	Atomic Mass Number	F.P. Fission Product	F.I.A.P. Activation Product	Z.A.P. Activation Product	Actinide (includes progeny)
W W W	Tungsten Tungsten Tungsten	181 185 188			¥ ¥ ¥
Re Re	Rhenium Rhenium	187 188			¥ ¥
Os	Osmium	194			¥
Ir Ir Ir Ir	Iridium Iridium Iridium Iridium	192 192m 194 194m			¥ ¥ ¥ ¥
Pt	Platinum	193			¥
Tl Tl Tl Tl	Thallium Thallium Thallium Thallium	206 207 208 209			¥	¥ ¥ ¥
Pb Pb Pb Pb Pb Pb Pb	Lead Lead Lead Lead Lead Lead Lead	204 205 209 210 211 212 214			¥ ¥	¥ ¥ ¥ ¥ ¥
Standard Chemical Symbol	Common Name of element	Atomic Mass Number	F.P. Fission Product	F.I.A.P. Activation Product	Z.A.P. Activation Product	Actinide (includes progeny)
Bi Bi Bi Bi Bi Bi Bi	Bismuth Bismuth Bismuth Bismuth Bismuth Bismuth Bismuth	208 210 210m 211 212 213 214			¥ ¥	¥ ¥ ¥ ¥ ¥
Po Po Po Po Po Po Po Po	Polonium Polonium Polonium Polonium Polonium Polonium Polonium Polonium	210 211 212 213 214 215 216 218			¥	¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥
At	Astatine	217				¥
Standard Chemical Symbol	Common Name of element	Atomic Mass Number	F.P. Fission Product	F.I.A.P. Activation Product	Z.A.P. Activation Product	Actinide (includes progeny)
Rn Rn Rn	Radon Radon Radon	219 220 222				¥ ¥ ¥
Fr Fr	Francium Francium	221 221				¥ ¥
Ra Ra Ra Ra Ra	Radium Radium Radium Radium Radium	223 224 225 226 228				¥ ¥ ¥ ¥ ¥
Ac Ac Ac	Actinium Actinium Actinium	225 227 228				¥ ¥ ¥
Th Th Th Th Th Th Th	Thorium Thorium Thorium Thorium Thorium Thorium Thorium	227 228 229 230 231 232 234				¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥
Standard Chemical Symbol	Common Name of element	Atomic Mass Number	F.P. Fission Product	F.I.A.P. Activation Product	Z.A.P. Activation Product	Actinide (includes progeny)
Pa Pa Pa Pa	Protactinium Protactinium Protactinium Protactinium	231 233 234 234m				¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥
U U U U U U U U	Uranium Uranium Uranium Uranium Uranium Uranium Uranium Uranium	232 233 234 235 236 237 238 240				¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥
Np Np Np Np Np	Neptunium Neptunium Neptunium Neptunium Neptunium	237 238 239 240 240m				¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥
Pu Pu Pu Pu Pu Pu Pu Pu	Plutonium Plutonium Plutonium Plutonium Plutonium Plutonium Plutonium Plutonium	236 238 239 240 241 242 243 244				¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥
Standard Chemical Symbol	Common Name of element	Atomic Mass Number	F.P. Fission Product	F.I.A.P. Activation Product	Z.A.P. Activation Product	Actinide (includes progeny)
Am Am Am Am Am	Americium Americium Americium Americium Americium	241 242 242m 243 245				¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥
Cm Cm Cm Cm Cm Cm Cm Cm	Curium Curium Curium Curium Curium Curium Curium Curium	242 243 244 245 246 247 248 250				¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥
Bk Bk	Berkelium Berkelium	249 250				¥ ¥
Cf Cf Cf Cf	Californium Californium Californium Californium	249 250 251 252				¥ ¥ ¥ ¥
Standard Chemical Symbol	Common Name of element	Atomic Mass Number	F.P. Fission Product	F.I.A.P. Activation Product	Z.A.P. Activation Product	Actinide (includes progeny)

AECL-9881. J. C. Tait, I. C. Gould, and G. B. Wilkin.
Derivation of Initial Radionuclide Inventories for the
Safety Assessment of the Disposal of Used CANDU Fuel.
AECL Whiteshell Nuclear Research Establishment, August, 1989.

---

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