Americium and plutonium in trigonal phosphates (NZP type) Am1/3[Zr2(PO4)3] and Pu1/4[Zr2(PO4)3]

Phosphates Am1/3[Zr2(PO4)3] and Pu1/4[Zr2(PO4)3] were synthesized and studied by X-ray diffraction. The X-ray patterns were indexed in trigonal crystal system, and the unit cell parameters were evaluated. The possibility of accommodation of actinides in the framework cavities of the structure of sodium zirconium phosphate was demonstrated for the first time. It was suggested that incorporation of highly charged Pu and Am cations in the framework cavities decreases the symmetry of the crystal structure to simple trigonal. The rates of Pu leaching from a ceramic material based on phosphate Pu1/4[Zr2(PO4)3] were measured.