Elaboration of phosphate ceramics as a safe form for halide salt waste immobilization of 'dry' fuel reprocessing

The conception of high level radwaste immobilization from M1-containing molten salts and their solid forms into NZP-like structure phosphate ceramics are considered. The crystal-chemical principle on radionuclide incorporation into this structure is described. The prepared NZP ceramics was tested and it was shown that they had stability to action of such factors as temperature (up to 1200-1600degC), pressure (up to 500 MPa), radiation (γ, up to 5·108 Gy), water solutions (up to 400degC, 60 MPa). Their structure is able to contain alkali elements up to 30-40%. Such monophase phosphate compositions may be formed at process of alkali chloride wastes solidification. The reactions of alkali chlorides, radionuclides, with phosphates are taken up here. (author)