Silver phosphate glasses for immobilization of radioactive iodine

Management of radioactive 129I is a challenging issue due to its significantly long half-life and negative health effects. In this study, silver iodide (AgI)-incorporated silver phosphate glasses were prepared to immobilize 129I for a long time. A melt-quenching method was employed to synthesize the glasses at 450 °C to prevent the evolution of I during the heat treatment. Characterization of the AgI-Ag2O-P2O5 specimens revealed that the addition of AgI was possible up to 60 mol% into the glassy matrix although there were some amounts of Ag4I(PO4) and AgI clusters. This result was supported by the structural analysis which showed that the major iodine environment was composed of Ag and O regardless of the specimen compositions. The normalized leaching rates obtained by the 7-day PCT-A test showed that the chemical stability of iodine was satisfactory with the lowest leaching rate of 1.7 × 10−4 g m−2/d. Our findings in this study demonstrate the potential of silver phosphate glass for the immobilization of radioactive 129I.