Ultra-fast preparation of UO2 fuel pellets by high pressure spark plasma sintering

A new sintering technique as a combination of ultra-fast spark plasma sintering and high-pressure sintering was employed to densify UO2 fuel pellets. UO2 pellets with a relative density of 97.5 % and inhibited grain growth were fabricated at 1000 °C under 150 MPa within only 4.5 min. Both short sintering time and high pressure might explain the inhibited grain growth and hence finer microstructures. UO2 fuel pellets prepared in this work exhibit excellent mechanical properties.