Exothermic Synthesis of Mineral-Like Matrices for the Immobilization of High-Level Waste (HLW)

Using the electrothermal explosion method, dense matrices were synthesized based on a mineral-like phase with a pyrochlore-type structure of the composition Y(TiZr)O and reduced Fe, containing 10 wt. % of high-level waste simulators. The elements of high-level waste simulators enter the pyrochlore structure in the form of isomorphic impurities and do not form independent phases. The resulting matrices have a cast structure and a porosity of less than 1%. It is shown that with an increase in the amount of waste to 20 wt. % pyrochlore structure is not formed, the main phase of the matrix is oxide Y(TiZr)O with a fluorite lattice. The formation of a perovskite-type phase of composition (La,Ce)TiO was also noted. The La and Ce elements are concentrated in the perovskite phase, while La and Ce are not found in the fluorite structure.