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TABLE 1 Basic Radioisotopes in High-Level Wastes from the Reprocessing of Spent Nuclear Fuel and Their Half-Lives

Basic Fission Products and Corrosion Elements (β- and γ-emitters)

Transuranic Actinides (α-emitters)

Radionuclide

T1/2, in years

Radionuclide

T1/2, in years

90Sr

29

237Np

2.1 × 106

93Zr

1.5 × 106

238Pu

89.9

99Tc

2.1 × 105

239Pu

2.4 × 104

126Sn

105

240Pu

6.5 ×103

129I

1.7 × 107

241Pu

14

137Cs

30

242Pu

3.78 × 105

147Pm

2.6

241Am

433

151Sm

93

242Am

152

154Eu

16

243Am

7.3 × 103

Activated corrosion products

243Cm

28

59Ni

7.5 × 104

244Cm

17.9

60Co

5.3

245Cm

8.5 × 103

63Ni

96

246Cm

4.76 × 103

with the study of various vitreous and crystalline materials based on silicates, phosphates, and titanates.3 For industrial-scale operations for this purpose, glasses are currently used—borosilicate glasses abroad4 and aluminophosphate glasses in Russia.5 The shortcoming of glasses is their limited capacity to incorporate actinides (especially plutonium) and their low chemical stability.6 The interaction of glass-like matrices with underground water is accompanied by the formation of colloidal particles7 in which radionuclides could migrate over great distances. In addition, glasses crystallize over time, further reducing the stability of radionuclide fixation due to the appearance of soluble phases—silicates or phosphates of the alkali and alkaline earth metals, molybdates, and so forth.

To manage them more efficiently wastes may be separated into radionuclide fractions.8 In one of these fractions the actinide content totals tens of percent by mass, and there is a significant amount of zirconium and lanthanides. The ratio of quantities of these elements in liquid high-level wastes from the reprocessing of spent fuel from various reactors is characterized as follows: actinides 10–15 percent by mass; lanthanides 60–65 percent by mass; and zirconium 20–25 percent by mass.9 Predominant among the actinides are uranium, neptunium, plutonium, and americium, while the lanthanide group is represented by neodymium, cerium, lanthanum, and praseodymium. Another group of wastes with high actinide content is created during the conversion of metallic weapons-grade plutonium into nuclear fuel.10

Besides glass, crystalline matrices represent an alternative waste form with high actinide content.11 More than 20 phases with various capacities for the



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