Vitrification and Chemical Durability of High‐Sodium Radioactive Waste Surrogates in Low‐Melting PbO–B 2 O 3 –ZnO Glasses

ABSTRACT Glass waste forms of high‐sodium low‐ and intermediate‐level radioactive waste (LILW) surrogates were prepared at relatively low temperatures with PbO–B 2 O 3 –ZnO (PBZ35) as the glass matrix. The waste forms were characterized by x‐ray diffraction analysis, Raman spectroscopy, scanning electron microscopy, and density tests. The high‐sodium LILW was evenly incorporated into the PBZ glass matrix, and its waste solubility limit in PBZ35 glass was up to 25 wt%. As the waste loading increases, CeO 2 crystals precipitate from the glass waste form. The chemical durability of the samples was analyzed using the PCT‐B and MCC‐1 methods performed at 90°C ± 1°C. In the PCT tests, the normalized leaching rates of Na for different waste loadings ranged from 10 −2 to 10 −1 g·m −2 ·d −1 . In the MCC‐1 test, the normalized leaching rates of Pb, B, Zn, Na, and Ce remained at the 10 −2 g·m −2 ·d −1 level, while those of Al, Sr, Cs, and Co remained at the 10 −3 g·m −2 ·d −1 level. As the leaching time increases, an Al(OH) 3 corrosion layer forms on the surface of the waste form, hindering the leaching of radionuclides.