The invention concerns a method for making at least one particulate matter, said method including the following successive steps: a) introducing in a vibrating grinder at least two powders each containing UO2 obtained by two different synthesis methods and having neighbouring specific surfaces; b) stirring the powders in the grinder, to form a particulate matter, the grinding intensity enabling the agglomerates and the aggregates of the powders to be fragmented without the crystallites being fragmented, and the grinding energy being such that all the agglomerates and aggregates are destroyed. The invention also concerns a particulate material obtained by said method.