Method for preparing a powder comprising particles of triuranium octoxide and particles of plutonium dioxide

A method for preparing a powder comprising particles of triuranium octoxide and particles of plutonium dioxide, comprising the steps of:

• a) preparing, by oxalic precipitations, an aqueous suspension S1 of particles of uranium(IV) oxalate and an aqueous suspension S2 of particles of plutonium(IV) oxalate;
• b) mixing the aqueous suspension S1 with the aqueous suspension S2 to obtain an aqueous suspension S1+2 comprising particles of uranium(IV) oxalate and particles of plutonium(IV) oxalate;
• c) separating the aqueous suspension S1+2 into an aqueous phase and a solid phase, the solid phase comprising the particles of uranium(IV) oxalate and the particles of plutonium(IV) oxalate;
• and
• d) calcining the solid phase to convert (1) the particles of uranium(IV) oxalate to particles of triuranium octoxide and (2) the particles of plutonium(IV) oxalate to the particles of plutonium(IV) dioxide, whereby the powder is obtained;
• and wherein steps b) and c) are performed simultaneously or successively.