Method of manufacture of compounds of the monazite type additives or not in actinides and application to the packaging of radioactive waste materials, rich in actinides and lanthanides

摘要

A method for making optionally actinide-doped monazite compounds, a method for conditioning actinide- and lanthanide-enriched radioactive waste by incorporating the waste into a monazite-based confinement matrix, and a radioactive waste conditioning block including a monazite matrix containing radioactive elements, are disclosed. The method comprises mixing solid-phase reagents including an inactive lanthanide metaphosphate compound having formula Ln(PO3)3 and one or more lanthanide oxides and/or one or more actinide oxides, or one or more compounds capable of producing said oxide(s) during the reaction sintering heat treatment, shaping the resulting mixture, and reaction sintering the shaped mixture, whereby monazite or a monazite compound is achieved.