Yu. M. Kulyako

Properties of Host Matrices with Incorporated U and Pu Oxides, Prepared by Melting of a Zircon-Containing Heterogeneous Mixture (by Virtue of Exo Effect of Burning Metallic Fuel)

Host matrices with incorporated U and Pu oxides are obtained by melting of a zircon-containing heterogeneous mixture by virtue of exo effect of burning metallic fuel and are characterized by chemical analysis, spectrophotometric and radiometric methods, luminescence, X-ray microanalysis, and atomic emission ICP analysis. The material balance with respect to the incorporated radionuclides is preserved. The radionuclide distribution throughout the bulk of the matrix is nearly uniform. Metallic inclusions based on V, Fe, Si, and Mn, but containing no U and Pu, are found in the matrix. The investigated matrices are quite stable even under hydrothermal conditions (250°C, ∼30 atm): the leachability of U and Pu was determined to be 0.1-0.2 and 0.03 ppm, respectively, and that of Zr, Mn, and Fe, > 0.06 ppm.

Magnesium potassium phosphate matrices for immobilization of high-level liquid wastes

Physicochemical properties of magnesium potassium phosphate (MPP) matrices for conservation of highly saline high-level liquid wastes (HLW) after their solidification at room temperature were studied comprehensively. The matrices showed high chemical stability to leaching of radionuclides and other components at various temperatures. The leaching indices of 239Pu, 237Np, 241Am, Sr, and Cs are in the range 12–14, and those of Tc, I, and Se, in the range 10–11. The mechanical strength (>20 MPa) and radiation resistance of the matrices and the chemical yield of radiolytically generated hydrogen (0.004 molecules/100 eV) were determined. The phase composition of the matrices and the character of radionuclide distribution in their bulk were determined. An enlarged installation was developed and fabricated at the Mayak Production Association, and solidification of simulated liquid radioactive wastes from this plant was performed in volumes of up to 2001.

Sorption of Np(V) on montmorillonite from solutions of MgCl2 and CaCl2

AbstractThe Np(V) distribution coefficients between montmorillonite and solutions of MgCl2 and CaCl2 were determined experimentally. The Np sorption decreases with increasing concentration of the supporting electrolyte. The sorption is very fast within the first several hours after the start of the experiment and then decelerates, reaching the equilibrium in approximately two weeks. The constants of binary ion exchange NpO2+-Mg2+ and NpO2+-Ca2+ on montmorillonite determined by fitting the experimental results are

Supercritical fluid extraction in modern radiochemistry

\log K_{NpO_2^ + - Mg^{2 + } } = 0.083 \pm 0.03

Sorption of Np(V) on kaolinite from solutions of MgCl2 and CaCl2

and

Behavior of fission products in the course of dissolution of simulated spent nuclear fuel in iron nitrate solutions and of recovery of uranium and plutonium from the resulting solutions

\log K_{NpO_2^ + - Ca^{2 + } } = 0.106 \pm 0.014