Structure and stability analysis of basaltic glasses for the immobilization of simulated waste

A power reactor in China was used as the subject, and based on the composition of its spent fuel, simulated waste basaltic glasses were prepared by the solid-state melting method. Among them, Ce⁴⁺/Ce³⁺, Nd³⁺ and La³⁺ are used to simulate Np⁴⁺/Np³⁺, Am³⁺ and U³⁺ in high-level nuclear waste (HLW), respectively. The structure, thermal stability and leaching characteristics of basaltic glasses with different contents of simulated waste were investigated. The XRD/SEM-EDX/Raman results revealed that the loading of simulated waste in basaltic glass reached ~ 25 wt%, and NiFe₂O₄ crystals precipitated when the simulated waste content reached 25 wt%. When the content of simulated waste reached 40 wt%, a small amount of yellow material precipitated from the upper surface of the sample. The DSC and ASTM standard MCC-1 results indicated that all the samples had good thermal stability and leaching resistance.