碱性体系下乏燃料氧化溶解行为与机理研究进展

Alkaline spent fuel reprocessing based on the carbonate system is a brief process with high safety, minimal waste, and ease of operation. Therefore, this process is suitable for the treatment of high burning spent fuel. Particularly, the oxidative dissolution of spent fuel under alkaline conditions is a key step in this process. To accurately discuss the research status of this key step during the alkaline process, the oxidation and dissolution behavior and the mechanism of spent fuel in the alkaline system were investigated. Results show that Na₂CO₃ and NH₄CO₃ are generally selected as the dissolution medium and H₂O₂ as the oxidant. U(Ⅳ) is oxidized to UO₂²⁺ in the dissolution process and complexes with O₂^2- and CO₃^2- ligands. The dissolution process is affected by various chemical and physical factors, such as pH value, temperature, radiation, and ultrasound. ·OH generated from irradiation or ultrasonic can significantly promote the oxidative dissolution of UO₂. However, basic research work, such as the relationship between dissolution rate and absorbed dose under irradiation conditions and the dissolution rate model under alkaline conditions, warrants enhancement.