Development and Testing of a New Porous Crystalline Matrix (Gubka) for Stabilizing Actinide Solutions

Abstract

This paper describes the results of a joint research program of the Russian institutes at St. Petersburg, Krasnoyarsk and Zheleznogorsk with the Idaho National Engineering and Environmental Laboratory. A new “Gubka” (“sponge” in Russian) material was used to sorb and stabilize surrogate problematic actinide solutions, which contained lanthanide mixtures in nitric acid and tracer americium-241, by using repeated saturation-drying-calcining cycles. These tests resulted in maximum loading up to about 45 wt.% nitrate salts after drying and 33 wt.% oxides after calcination. The rates of americium-241 recovery were measured in 6 M nitric acid at 60°C. Gubka samples loaded with cerium and neodymium oxides were hot pressed at 29 MPa and 20-1000°C, resulting in a 35 % volume reduction.