Abstract: The invention relates to a powder of an alloy based on uranium and molybdenum in a metastable ? phase, which is formed of particles which have an elongation index at least equal to 1.1, a non-zero closed porosity value and which are composed of grains having a molybdenum content, for which the variations within the same grain are of at most 1% by mass. It also relates to a method allowing preparation of this alloy powder as well as to the use of said powder for manufacturing nuclear fuels and targets for producing radioisotopes. Applications: Manufacturing of nuclear fuels, notably for experiment nuclear reactors; manufacturing of targets for producing radioisotopes, notably for the medical industry.

Abstract: A method for preparing a powder of an alloy based on uranium and molybdenum in a metastable ? phase is provided, 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.

Abstract: The invention relates to a powder of an alloy comprising uranium and molybdenum in ?-metastable phase, a composition of powders comprising this powder, and the uses of said alloy powder and of said composition of powders. The alloy powder comprising uranium and molybdenum in ?-metastable phase according to the invention is formed of particles comprising a nucleus which consists of said alloy, and which is covered with a layer of alumina positioned in contact with this nucleus. Applications: manufacture of nuclear fuel elements and, in particular, of fuel elements for experimental nuclear reactors; manufacture of targets intended for production of radioelements, which are useful in particular for medical imaging, such as technetium 99m.

Abstract: The invention relates to a powder of an alloy based on uranium and molybdenum in a metastable ? phase, which is formed of particles which have an elongation index at least equal to 1.1, a non-zero closed porosity value and which are composed of grains having a molybdenum content, for which the variations within the same grain are of at most 1% by mass. It also relates to a method allowing preparation of this alloy powder as well as to the use of said powder for manufacturing nuclear fuels and targets for producing radioisotopes. Applications: Manufacturing of nuclear fuels, notably for experimental nuclear reactors; manufacturing of targets for producing radioisotopes, notably for the medical industry.

Abstract: The invention relates to a method for preparing a powder of an alloy based on uranium and molybdenum in a metastable ? 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.