The physico-chemical stability of bituminized EUROCHEMIC medium-level reprocessing waste

The physico-chemical stability of bituminized reprocessing sludges, called EUROBITUM, has been investigated by leaching and ageing tests. Both inactive simulates with sizes up to 11 l and real fully active but small samples of less than 1 ml, were considered. The leaching of the waste constituents in very incongruent: NaNO3 would be leached quantitatively from real drums within a few thousands of years, based on extrapolation from smaller samples, while the alpha active isotopes (Pu, Am) are quite strongly immobilized in the bituminisate. The influence of clay in solution and pressure upon leaching is not predominant. The swelling of Eurobitum upon exposure to liquid may be of concern. Ageing periods up to seven years show that the waste form is becoming harder and denser. (orig.)