Effects of heating conditions on the particle characteristics of uranium oxide powders synthesized from uranyl nitrate solutions via microwave heating

Segawa, Tomoomi ; Kawaguchi, Koichi  ; Ishii, Katsunori ; Fukasawa, Tomonori*; Fukui, Kunihiro*

In the conversion process, a mixed solution of plutonium nitrate and uranyl nitrate recovered from spent fuel is converted into mixed oxide through microwave heating. Both, improvements in heating efficiency and powder characteristics, are important in microwave heating denitration. This study aims to advance microwave heating denitration. Thus, we investigated the effects of heating conditions when using an adiabator and the temperature rising rate of the particle characteristics of a uranium trioxide (UO) powder synthesized from uranyl nitrate solutions through microwave heating. The temperature rising rate significantly increased when the adiabator was used compared to when not used at the same microwave power. The mass median diameters of the UO powders decreased with the increasing temperature rising rate with and without using the adiabator. Heating conditions can control the particle characteristics of UO powders.