Nitridation of dysprosium and zirconium metals in liquid cadmium

Sato, Takumi  ; Hayashi, Hirokazu ; Nakamura, Hitoshi*; Omori, Takashi*

In pyrochemical reprocessing of spent nitride fuel for transmutation of MA using ADS, actinides are recovered in a liquid cadmium cathode and converted to nitrides again by heating in N gas stream. Nitridation of actinide-Cd alloys has been achieved on 1 to 10 g-Cd scale. However, experimental data of a larger scale test is required to design an industrial scale equipment. Furthermore, understanding the nitridation behaviour of Zr in Cd is necessary to determine the process condition because Zr is recovered in a liquid cadmium cathode with actinides at high current density in the electrorefining process. In the present study, the apparatus for 100 g-Cd scale tests is developed and the nitride formation reactions of Dy-Cd and Zr-Cd alloys have been studied in the temperature range of 973-1073 K in N gas stream. Dy was used as a surrogate material of MAs and Pu. Most of Dy and Zr in Cd were converted to nitride at 1073 and 973 K, respectively.