Effect of PbO on the chemical durability of low-temperature PbO–B2O3–ZnO glass for cesium immobilization

Highly reactive fission product cesium may volatilize at high temperatures. PbO–B2O3–ZnO glass with low melting temperature and excellent chemical durability can be used as a potential matrix for immobilizing Cs. In this work, five PbO–B2O3–ZnO glasses with different contents of Pb were synthesized via a melt-quenching process. These specimens were characterized with XRD, Raman, DTA and viscosity measurements. The results showed that the melting temperature decreases, viscosity decreases and structural polymerization increases with increasing lead content. Cs-doped 35PbO–60B2O3–5ZnO glasses were synthesized at low temperatures. XRD results revealed the amorphous nature of the glass solidified bodies. EDS and ICP-MS studies confirmed that Cs is retained in the glass. Clear vitrified waste products containing up to 13.6 wt% Cs were obtained. The chemical durability of the samples was evaluated via PCT-A and MCC-1 method. For the glass solidified body comprising a Cs/matrix ratio of 0.136, the leaching rate of Cs was 1.6 × 10−1g m−2 d−1 from the PCT test, which indicates that it has a good chemical stability. 35PbO–60B2O3–5ZnO glass was expected to be a suitable matrix for Cs immobilization.