The nuclear fuel pellets are produced by sintering a material containing U02 uranium dioxide obtained from a powder from a UF6 uranium hexafluoride conversion process. The powder obtained directly from a UF6 uranium hexafluoride conversion process is introduced into a vessel containing moving compression and mixing bodies and the vessel is agitated in such a way that the powder is displaced inside the volume of the vessel according to three non-coplanar axes such that it is compressed between the moveable bodies and between the moveable bodies and the walls of the vessel until a particulate material is formed, having a higher density in relation to the powder obtained by the conversion process and the particulate material directly obtained by agitation inside the vessel is used to shape the raw fuel pellets which undergo sintering. Preferably, the vessel is set into a vibratory motion during treatment. Extremly varied additives can be introduced into the vessel either before or duringtreatment, by agitation inside the vessel.