Silver phosphate glasses for immobilization of radioactive iodine

Management of radioactive 129 I 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 129 I 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-Ag 2 O-P 2 O 5 specimens revealed that the addition of AgI was possible up to 60 mol% into the glassy matrix although there were some amounts of Ag 4 I(PO 4 ) 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 129 I.