New Decladding System in the Reprocessing Process for Fast Reactor Fuel

As a feasibility study on commercialized fast reactor cycle systems, Japan Nuclear Cycle Development Institute (JNC) has been developing the fuel decladding system for the dry reprocessing process (Oxide electrowinning process) and aqueous reprocessing process. In the oxide electrowinning process, the spent fuel pins should be crushed and grained for quick dissolution in the molten salt at electrolyzer. For the fuel crushing method, the heat treatment method such as a voloxidation might not be applicable due to the high plutonium content such as a fast reactor fuel. Therefore, JNC proposed innovative decladding system with mechanical decladding devices. The decladding system consists of the fuel pin crushing process, the hull separation process and the fuel recovery process. In the fuel pin crushing process, a disassembled spent fuel pin is crushed and powdered by the mechanical shredding device, and in the following process, the crushed product with hull and fuel fragments is separated to fuel element and metallic element (mainly hull fragments) by the magnetic separator. Then the induction-melting device recovers small amount of fuel element contaminated in the metallic element. The recovered fuel element is fed back to the electrolyzer. In this paper, the outline of this new decladding system and its innovative devices will be descried.