Extraction of Actinides and Lanthanides by Supercritical Fluid

Reprocessing of used nuclear fuel and treatment of nuclear waste are important issues for the sustainable development of nuclear energy. It is necessary to develop novel nuclear waste treatment technologies to meet the goal of minimizing the secondary liquid waste. Supercritical fluids are considered green solvents in chemical engineering process. It gains growing interest to treat nuclear waste using supercritical fluid extraction recently, because it can greatly decrease the secondary liquid waste with high radioactivity. During the past two decades, extraction of actinides and lanthanides by supercritical fluid has been intensively studied in some countries, and many important progresses have been made. However, the prospect of industrial application of supercritical fluid extraction technology in reprocessing of used nuclear fuel and treatment of nuclear waste is still unclear. In this paper, extraction of actinides and lanthanides from various matrixes or from their oxides by supercritical fluid including the experimental results, extraction mechanism and kinetic process was reviewed. The engineering demonstration projects were introduced. The trend of industrial application of supercritical fluid extraction technology in nuclear waste management was also discussed.