Spent fuel reprocessing and fuel debris treatment technologies by the fluoride volatility method

Fluorine gas reacts with almost all elements, and uranium (U) and plutonium (Pu) hexafluorides are volatile while many fluorides are non-volatile. These fluorides properties enable the separation of U and Pu from other elements in the spent fuel and the fuel debris generated by the operation and the severe accident of nuclear reactors, respectively. The authors have been developing the advanced reprocessing and fuel debris treatment technologies which utilize the fluoride volatility method. This paper describes the features of fluoride volatility method and both technologies' process flows and typical experimental results which have been obtained mainly on fluorination process using simulated and actual spent fuel and simulated fuel debris. The process flows consist of pulverization of the spent fuel or fuel debris if necessary, their fluorination, purification of gaseous and solid products (fluorides) for reprocessing, recovery of U and Pu (no Pu isolation) and off-gas and solid waste treatments. The experimental results clarified basically the applicability of fluoride volatility method to both technologies. (author)