METHOD FOR PREPARING A POWDER OF AN ALLOY BASED ON URANIUM AND MOLYBDENUM

The invention relates to a method for preparing a powder of an alloy based on uranium and molybdenum in a metastable gamma phase, which comprises: a) putting at least one first reagent selected from uranium oxides and mixtures thereof, uranium fluorides and mixtures thereof, into contact with a second reagent consisting in molybdenum and a third reagent consisting in a reducing metal, the first, second and third reagents being in a divided form; b) reacting the reagents at a temperature>=the melting temperature of the third reagent and under an inert atmosphere, whereby this reaction leads to the formation of the alloy comprising uranium and molybdenum in the form of a powder, for which the particles are covered with a reducing metal oxide or fluoride layer; c) cooling the so formed powder at a rate at least equal to 450° C./hour; and d) removing the reducing metal oxide or fluoride layer which covers the particles of the powder of the alloy comprising uranium and molybdenum. It also relates to a method for manufacturing a nuclear fuel implementing this method. Applications: Manufacturing of nuclear fuels, notably for MTRs.