Leaching of well-characterised highly active waste glasses and spent fuel
The aim of this research is to compare the long-term leaching behaviour of different waste forms under repository conditions. Vitrified high-level waste from the reprocessing of irradiated nuclear fuels and unprocessed spent fuel are considered as alternative waste forms. In the case of glass, the chemical analyses of the leachates and the electron microprobe analyses of the gel-layers indicate that the major glass constituents are leached from the surface congruently, leaving an altered layer. The leach test procedure (static or dynamic) has a great influence on this altered layer and on the leaching rate. Transition metals such as Zr, Fe, Cr, Tc, noble metals, rare earth metals and actinides are removed at a slower rate or remain trapped in the gel-layer. Leaching of fully active waste glass in autoclaves with different container materials has a strong influence on the corrosion rate of the glass. Titanium containers have very little influence on the analysis of the leachates. This is especially important for sensitive analytical techniques, such as ICP-MS. Fuels are ceramics and so follow a completely different corrosion mechanism. Similar leach rates are measured for UO(2) and MOX (mixed U, Pu oxide) fuel, but for the highly mobile fission products CS, I and Tc they are higher in the case of MOX fuel.
Bibliographic Reference: Paper presented: 1991 Joint International Waste Management Conference, Seoul (KR), Sept. 21-26, 1991
Availability: Available from (1) as Paper EN 36074 ORA
Record Number: 199110688 / Last updated on: 1994-12-02
Original language: en
Available languages: en