Fission Products in Spent Fuel

Detailed reports of used LWR fuel content in descending order of total radiotoxicity per element (from validated ORIGEN2 simulations):

Detailed radiotoxicity curves were computed from radioactivity of fission products having half lives longer than five years.

Elements in Electrorefiner Electrolyte
from Spent Fuel Stored for Ten Years

Element Mass
Grams 		Amount
Moles 		Radiotoxicity
Sieverts 		Atomic
Number
Antimony 29.06 0.2379 6.77e+4 51
Arsenic 0.2982 3.98e-3 0 33
Barium 2776 20.23 0 56
Beryllium 2.29e-4 2.32e-5 1.81e-4 4
Bromine 31.96 0.395 0 35
Caesium 3680 27.3 6.75E+7 55
Carbon 4.02e-5 2.87e-6 3.84e-3 6
Europium 233.4 1.525 6.24e+5 64
Gallium 7.93e-6 1.14e-7 0 31
Germanium 0.9951 0.01322 0 32
Indium 2.892 0.0252 1.99e-8 49
Iodine 357.6 2.784 196.5 53
Lithium 2.57e-5 4.24e-5 0 3
Rubidium 524.5 6.079 1.76e-3 37
Samarium 1284 8.6 2017 62
Selenium 84.68 1.048 66.35 34
Silver 115.4 1.06 30.36 47
Strontium 1135 12.76 8.70e+7 38
Tellurium 749.1 5.797 1.31e+4 52
Thulium 9.54e-5 5.64e-7 2.17e-4 69
Tin 139.9 1.152 213.8 50
Ytterbium 4.30e-5 2.53e-7 0 70
Yttrium 676.2 7.605 0 39
Zinc 9.72e-3 1.40e-4 0 30
Note: Yttrium 90, half life 2.671 days, decay product of 90Sr, half life 28.79 years. Radiotoxicity is included in 90Sr.

Differences in Electrolyte Content at 50 Years

Element Mass
Grams 		Radiotoxicity
Sieverts 		Remarks
Antimony 27.46 19.64 1.61 grams 125Sb, half life 2.759 years → 125Te.
Barium 3650 0 137Cs, half life 30.04 years → 137mBa, half life 2.552 minutes → 137Ba.
Caesium 2806 23.87e+6 866 grams 137Cs, half life 30.04 years → 137mBa.
Europium 204.3 23.6e+3 28.28 grams 154Eu, half life 8.593 years → 154Gd.
Samarium 1290 1483 5.5 grams 151Sm, half life 90 years → 151Eu.
Silver 115.4 0.0032 61.7 μg 110mAg, half life 249.8 days → 110Ag.
Strontium 757.5 33.57e+6 377.8 grams 90Sr half life 28.79 years → 90Y, half life 2.671 days → 90Zr.
Tellurium 750.7 0.5873 22.52 mg 125mTe, half life 578.4 days → 125Te.
Yttrium 676.1 0 90Sr, half life 28.79 years → 90Y, half life 2.671 days → 90Zr.
Note: Yttrium 90, half life 2.671 days, decay product of 90Sr, half life 28.79 years. Radiotoxicity is included in 90Sr.

Trivalent Rare Earth Elements Deposited in
Electrorefiner Third Cathode from Spent Fuel Stored for Ten Years

Element Mass
Grams 		Amount
Moles 		Radiotoxicity
Sieverts 		Atomic
Number
Cerium 3607 25.61 3.39E+4 58
Dysprosium 2.568 0.01591 0 66
Erbium 0.1055 6.35e-4 0 68
Gadolinium 223.6 1.435 6.82e-3 64
Holmium 0.2892 1.753e-3 0.4656 67
Lanthanum 1849 13.31 5.97e-9 57
Neodymium 6143 42.41 0 60
Praseodymium 1689 11.99 326 59
Promethium 11.02 0.07503 9.84e+4 61
Terbium 4.337 0.02729 6.68e-11 65

Differences in Trivalent Rare Earth Elements Deposited in
Electrorefiner Third Cathode Content at 50 Years

Element Mass
Grams 		Radiotoxicity
Sieverts 		Remarks
Cerium 3607 0 55.20 mg 144Ce, half life 250 days → 144Pr.
Gadolinium 258.2 2.971e-9 154Eu → 154gd; 153Gd, half life 240.4 days → 153Eu.
Praeseodymium 1689 0 144Ce, half life 250 days → 144Pr, half life 17.28 minutes → 144Nd. After 144Ce has decayed, there is no further source for 144Pr.
Promethium 0.0003 0 11.02 grams 147Pm, half life 2.623 years → 147Sm.

Elements in Electrorefiner Anode Basket
from Spent Fuel Stored for Ten Years

Element Mass
Grams 		Amount
Moles 		Radiotoxicity
Sieverts 		Atomic
Number
Cadmium 198 1.776 5.10e+4 48
Molybdenum 5059 51.89 0 42
Niobium 0.00706 7.59e-5 5.227 41
Palladium 2359 22.31 0.254 46
Rhodium 611.3 5.94 7.574 45
Ruthenium 3465 34 2.01e+5 44
Technetium 1136 11.49 456.1 43
Zirconium 5449 58.51 109.8 40

Differences in Anode Basket Content at 50 Years

Element Mass
Grams 		Radiotoxicity
Sieverts 		Remarks
Cadmium 197.7 7625 234.8 mg 113mCd, half life 14.1 years → 113Cd.
Niobium 0.0265 10.59 4.27 mg 93Zr, half life 1.53e+6 years, → 93mNb, half life 16.13 years.
Rhodium 611.3 533.4e-6 141.5 μg 102Rh, half life 2.902 years, → 102Ru.
Ruthenium 3464 226.9e-9 231.6 mg 106Ru, half life 1.02 years, → 106Ru.
Zirconium 5827 109.8 378 grams 90Sr, half life 28.79 years, → 90Y, half life 2.671 days, → 90Zr.

Gases

Amount grams
Element 10 years 50 years Remarks
Krypton 533.0 516.3 16.7 grams 85Kr, half life 10.75 years → 85Rb.
Xenon 8024 8024
Note: Radiotoxicities are not computed for inert gases.