Evaluation on the denitration characteristics of metal nitrate aqueous mixed solution by microwave heating and the complex relative permittivity

Segawa, Tomoomi ; Kawaguchi, Koichi  ; Ishii, Katsunori ; Suzuki, Masahiro ; Fukasawa, Tomonori*; Fukui, Kunihiro*; Kitazawa, Toshihide*

In the process of the spent fuel reprocessing, a mixture of uranyl nitrate and plutonium nitrate is converted to a mixed oxide powder by the microwave heating direct denitration method. In the case of assuming the heterogeneous cycle in the Na-cooled fast reactor, it is required to denitrate a solution containing mainly MA for which microwave heating denitration characteristics have not been clarified, therefore, it is necessary to obtain microwave heating denitration characteristics data for metal nitrate mixed aqueous solutions. In this study, microwave heating denitration characteristics of copper nitrate and nickel nitrate mixed solution and the complex relative permittivity of the final and intermediate products were evaluated. It was clarified that the mixing ratio and the microwave energy loss of metal oxides as final products remarkably affect the denitration characteristics.