PROCESS FOR THE PREPARATION OF A POWDER COMPRISING URANIUM OXIDE UO2, POSSIBLY PLUTONIUM OXIDE PUO2 AND POSSIBLY AMERICON OXIDE AMO2 AND / OR AN OXIDE OF ANOTHER MINOR ACTINID

摘要

The invention relates to a process for the preparation of a powder comprising uranium oxide UO2, optionally plutonium oxide PuO2 and optionally americium oxide AmO2 and / or an oxide of a other minor actinide MO2, M being neptunium or curium comprising the following stages: a) a stage of preparation of an aqueous suspension comprising the bringing into contact of water; optionally a uranium oxide powder UO2, a plutonium oxide powder PuO2 and optionally an americium oxide powder AmO2 and / or an oxide powder of another minor actinide MO2, M being neptunium or curium; at least one additive chosen from deflocculating agents, organic binders and mixtures thereof, the said additive (s) being added in an amount such that the dynamic viscosity of the aqueous suspension does not exceed 1000 mPa.s; b) a cryogenic granulation step of the suspension prepared in a); c) a step of lyophilization of the granules obtained in c), whereby a powder is obtained comprising uranium oxide UO2, plutonium oxide PuO2 and optionally americium oxide AmO2 and / or an oxide of another minor actinide MO2, M being neptunium or curium.