Study on microwave heating of Pu/U mixed nitrate medium in solid state on denitration process

Imai, Suguru*; Taguchi, Kenji*; Kashiwa, Tatsuya*; Kawaguchi, Koichi  ; Segawa, Tomoomi 

In the nuclear cycle system, reprocessing solutions (plutonium and uranium mixed nitrate solution) produced from spent nuclear fuel is converted to Mixed Oxide (MOX) by a microwave heating (MH) method in Japan. The electric constant of the reprocessing solution is varied by its phase state on heating and denitration reaction and affects the microwave heating property. It is important to understand the property of the microwave heating for improving the efficiency. Therefore the temperature distribution of the solid state of the reprocessing solution is investigated by the electromagnetic analysis and thermal analysis using FDTD method and thermal analysis method. As a result, the absorbed power of the solid-state Pu-U mixed nitrate are concentrated at upper surface and periphery, and generated heat flows to below.