Abstract: Pyroprocessing, based on molten salts electrolysis, is the most promising technology for dry reprocessing of different types of spent fuels, such as oxide and metallic fuels. Pyroprocessing technology involves four main processes, which are head-end treatment, electrochemical reduction, electrorefining and electrowinning, and waste treatment. This paper provides a state of the art review of the basic processes and unresolved key issues of pyroprocessing technology.