Mineral-Like Consolidating Matrix Materials for Solidification of Technetium and Technetium–Neptunium Fractions

Abstract

The phase formation of the phosphates Tc_0.5Zr_0.5P₂O₇, Tc_0.25Zr_0.75P₂O₇, and Tc_0.25Np_0.25Zr_0.5P₂O₇ for the immobilization of technetium and technetium–neptunium fractions was studied. The powders were obtained by precipitation from solution. The target phase formation temperature was 600°C. The compounds obtained are single-phase products and crystallize in the cubic system, space group Pa–3. The solidification of the real technetium–zirconium fraction from VVER-1000 SNF processing was performed. The hydrolytic durability of the samples was studied by long-term static leaching. The degrees of leaching were as follows: Tc, no more than 0.03%; Np, 0.008%; Zr, less than 0.001%.