Journal of Nuclear Fuel Cycle and Waste Technology

Processing and equipment were tailored for engineering scale fabrication of UO2 porous pellets, a feed material for the electrolytic reduction process in the PRIDE (PyRoprocessing Integrated DEmonstration) facility at KAERI (Korea Atomic Energy Research Institute). The starting materials, UO2 powder and pre-milled surrogate oxide powders, were proportioned to simulate the chemical composition of spent fuel (so-called Simfuel). The Simfuel powders were homogenized by mixing, compacted into a pellet shape, and finally heat treated using a tumbling mixer, rotary press, and sintering furnace. After sintering at 1450℃ for 24 h in 4% H2-Ar, the average bulk density of the UO2 Simfuel pellets was 6.89 g·cm-3, which meets the standard of the following electrolytic reduction process. In addition, the results of a microstructural analysis demonstrated that the sintered Simfuel UO2 porous pellets accurately simulate the properties of spent fuel in terms of the formation of second phases. These results provide essential information for the massive fabrication of UO2 porous pellets for engineering scale pyroprocessing research.

Keywords

Pyroprocessing,Engineering scale,Head-end process,Feed material,Porous pellet