Cs2SnCl6-Glass Composites for Highly Efficient Immobilization of Cs+ in Chlorine-Containing Molten Salts

137 Cs has become one of the key challenges in the dry reprocessing of spent fuel due to its poor separability and high radioactivity. The synthesis of Cs 2 SnCl 6 for the removal of CsCl from waste salts and the preparation of Cs 2 SnCl 6 -glass composites was investigated in this study. The optimal conditions for the hydrothermal synthesis of Cs 2 SnCl 6 are a reaction at 150°C for 6 h, and XRD results indicate that the product is a pure cubic phase. CsCl is removed from LiCl-KCl-CsCl waste salts by the synthesis of Cs 2 SnCl 6 . This method enables efficient and selective separation of Cs + from waste salts with a Cs + content of 2.5–10 wt.%, achieving a removal efficiency of over 96%. The glass composites have a maximum embedding rate of 30 wt.%. Cs + and Cl − are uniformly distributed in the glass matrix, and the glass matrix exhibits good compatibility with Cs 2 SnCl 6 . The PCT test showed that the normalized leaching rates of Cs + and Cl − on the 28th day were as low as 1.6×10 − 4 and 3.4×10 − 4 g·m − 2 ·d − 1 , respectively, demonstrating that the Cs 2 SnCl 6 -glass composite exhibits excellent leaching resistance.