Solid-state mechanochemical reduction combined with subsequent melting consolidation was suggested as a technical option for the oxide reduction in pyroprocessing. Ni ingot was produced from NiO as a starting material through this technique while Li metal was used as a reducing agent. To determine the technical feasibility of this approach for pyroprocessing, which handles spent nuclear fuels, thermodynamic calculations of the phase stabilities of various metal oxides of U and other fission elements were made when several alkaline and alkali-earth metals were used as reducing agents. This technique is expected to be beneficial, not only for oxide reduction but also for other unit processes involved in pyroprocessing.

1. Introduction
2. Experimental Methods
3. Results and Discussion
    3.1 Feasibiilty Test Using NiO
    3.2 Thermodynamic Investigation
    3.3 Modification of Pyroprocessing
4. Conclusions
REFERENCES

• Sung-Wook Kim(Korea Atomic Energy Research Institute) Corresponding Author
• Seung Youb Han(Korea Atomic Energy Research Institute)
• Junhyuk Jang(Korea Atomic Energy Research Institute)
• Min Ku Jeon(Korea Atomic Energy Research Institute)
• Eun-Young Choi(Korea Atomic Energy Research Institute)