Patent ID: 8481799

Claim:
A method for packaging radioactive wastes, wherein the following successive steps are carried out: a/ radioactive wastes are treated for which the composition of the dry extract after calcination at 950° C., called starting composition hereafter, comprises at least 90% of compounds selected from CaO, Fe 2 O 3 , SiO 2 , Al 2 O 3 and B 2 O 3 , and the composition of said wastes is supplemented so as to attain a target composition of said supplemented wastes after calcination, and b/ said supplemented radioactive wastes are melted and c/ said melt is cast in a container, so as to obtain after cooling, a monolith product comprising a synthetic either glassy or vitro-crystalline rock, having said target composition, wherein said starting composition and said target composition meet the following definitions, in a ternary (CaO, SiO 2 and X 2 O 3 ) system, wherein X 2 O 3 is a trivalent oxide or a mixture of trivalent oxides selected from Al 2 O 3 , Fe 2 O 3 et B 2 O 3 : for said starting composition: P C and P X are less than 90%, and P S is less than 75%, and for said target composition: P C is from 35 to 60%, and P S is from 10 to 45%, with, in both cases: P C +P S +P X =100%, and P X =P A +P H +P B , with P C =[M C /(M C +M S +M A +0.28M H +2M B )]×100%, and P S =[M S /(M C +M S +M A +0.28M H +2M B )]×100%, and P A =[M A /(M C +M S +M A +0.28M H +2M B )]×100%, and P H =[0.28M H /(M C +M S +M A +0.28M H +2M B )]×100%, and P B =[2M B /(M C +M S +M A +0.28M H +2M B )]×100%, and P i and M i , with i=C, S, A, H or B, are the mass percentages (P i ) and the masses (M i ) of CaO (i=C), SiO 2 (i=S), Al 2 O 3 (i=A), Fe 2 O 3 (i=H) et B 2 O 3 (i=B) respectively.