Method for preparing a powder comprising uranium oxide uo<2>, optionally plutonium oxide puo<2> and optionally americium oxide amo<2> and/or an oxide of another minor actinide

Abstract

The invention relates to a method for preparing a powder comprising uranium oxide UO<2>, optionally plutonium oxide PuO<2> and optionally americium oxide AmO<2> and / or an oxide of another minor actinide MO<2>, M being neptunium or curium, comprising the following steps: a) a step of preparing an aqueous suspension according to which water is brought into contact with: optionally a uranium oxide powder UO<2>, a plutonium oxide powder PuO<2> and optionally an americium oxide powder AmO<2> and / or an oxide powder of another minor actinide MO<2>, M being neptunium or curium; at least one additive selected from deflocculating agents, organic binders and mixtures thereof, said additive or additives being added in such an amount that the dynamic viscosity of the aqueous suspension does not exceed1000 mPa.s; b) a step for the cryogenic granulation of the suspension prepared in a); c) a step of freeze drying the granules obtained in b), whereby a powder comprising uranium oxide UO<2>, plutoniumoxide PuO<2> and optionally americium oxide AmO<2> and / or an oxide of another minor actinide MO<2> is obtained, M being neptunium or curium.

Description

technical field [0001] The invention relates to a method for preparing UO containing uranium oxide 2 , optional plutonium oxide PuO 2 and optionally americium oxide AmO 2 and / or powders of other minor actinide oxides. [0002] It should be noted that for the remainder of this disclosure, the term "minor actinides" refers to actinides other than uranium, plutonium, and thorium that are formed in reactors by the continuous neutron capture of standard fuel cores. The actinides are americium, curium and neptunium. [0003] More specifically, the present invention relates to a process for preparing a powder that is flowable, has a narrow monomodal trend in particle size analysis, and can be compacted without premixing, and more specifically, the Said powders may have the following specific physicochemical properties: [0004] Good spontaneous flow ability; [0005] Particle size distributions with a unimodal tendency centered at values ​​between 150 μm and 350 μm; [0006] G...

AI Technical Summary

Problems solved by technology

Although this method does not utilize the steps of grinding, mixing, and sieving, it still produces a non-negligible ratio of fines during spraying