Determination of Transmutation Effects in Crystalline Waste Forms

Microstructure and Cs Behavior of Ba-Doped Aluminosilicate Pollucite Irradiated with F+ Ions

“…A previous TEM study , showed that a diluted, aged sample of 137 CsAlSi 2 O 6 ·0.5H 2 O is susceptible to electron-irradiation-induced amorphization at 200 keV; volatilization of Cs in the sample under electron irradiation was also observed. A later study found that an aged 137 Cs-containing pollucite, after decay of nearly 16% of the total 137 Cs over the elapsed 20 years, exhibited a homogeneous, crystalline matrix with no evidence of distinct Ba phases. It should be noted that the initial pollucite contained only a small mass fraction (0.0375) of 137 Cs substitution for stable 133 Cs.…”

“…Removal of 137 Cs and 90 Sr from the spent fuel could significantly reduce the repository size for nuclear wastes. 2 Spent fuels are chemically reprocessed by ion exchange for 137 Cs and by solvent extraction for 90 Sr. 3 Prior to disposal, the radionuclides must be immobilized in a solid form to prevent their release to the environment. Ideal waste forms are mechanically strong, chemically stable, resistant to selfirradiation-induced damage, and highly thermally conductive.…”