Corrosion Behavior of a Powdered Simulated Nuclear Waste Glass in the Presence of Bentonite

Static corrosion tests of a powdered simulated waste glass were performed in deionized water with and without bentonite at 90°C for periods of up to 130 days. The glass irradiated with thermal neutron for activating Cs in the glass was used as a glass specimen in order to determine the sorption of Cs on bentonite. In the corrosion tests without bentonite, it was observed that normalized elemental mass loss: (NL) values for soluble elements (B, Li, Na and Mo) were larger than those for Si by a factor of three and continued to increase after saturation of Si. In the corrosion tests in the presence of bentonite, it was observed that the glass corrosion was enhanced, and a large amount of Cs was sorbed on bentonite.

The experimental results were analyzed by use of some corrosion models. The analysis showed that diffusion of the soluble elements is expected to be a dominant process for the glass corrosion, as well as the dissolution/precipitation reactions. In addition, it is expected that the glass corrosion in the presence of bentonite is largely affected by both ion-exchange equilibrium of the aqueous phase with Na-montmorillonite and precipitation of sepiolite from dissolution of dolomite.     

Separation of Zirconium-95, 97 and Niobium-95, 97 from Fission Product-Mixtures and Irradiated Uranium by an Extraction Method using 8-Quinolinol

An 8-quinolinol-extraction method has been applied to separate ⁹⁵Zr-⁹⁵Nb or ⁹⁵Nb from fission product mixtures and/or irradiated uranium. Radiochemically pure nuclides can be separated simply and rapidly from either origin. In the separation of ⁹⁵Zr-⁹⁵Nb, the extraction is made from a solution of pH 4.5 to 5.5, containing acetate as masking agent. ⁹⁵Nb is extracted from a solution of pH 4.8 to 5.2, containing fluoride as masking agent, in the presence of uranium. ⁹⁵Nb can be saparated from ⁹⁵Zr and other fission products by extraction from a solution of pH 5.3 to 8, containing EDTA as masking agent. In these cases, after the first extraction, the chloroform solution should be washed with water to remove any remaining extraneous uranium or fission products. The addition of a small quantity of sulfite is required to prevent the extraction of ¹⁰³Ru.

The method can be also used for the separation of the short-lived nuclides, ⁹⁷Zr-⁹⁷Nb or ⁹⁷Nb, from irradiated uranium.