Effect of Fe sub 2 O sub 3 /ZnO on Two Glass Compositions for Solidification on Swedish Nuclear Wastes

摘要

Low melting alkaliborosilicate glasses have been considered for use in the immobilization of high level radioactive wastes for years. A recent study comparing the surface behavior of two nuclear waste glasses concluded that ''Addition of Fe sub 2 O sub 3 to a soda borosilicate nuclear waste glass significantly reduces damage by water attack because of a Fe-rich film that forms on the glass surface''. However, in the previous study there were significant differences in the concentration of SiO sub 2 , B sub 2 O sub 3 , CaO and simulated fission products in the glasses which made it impossible to ascribe the improved leach resistance solely to Fe sub 2 O sub 3 content. Thus, the objective of the present investigation is to compare the leaching and surface behavior of two nuclear waste glasses which differ only by the substitution of Fe sub 2 O sub 3 for some of the ZnO in the glass. By this comparison the authors hope to establish whether Fe sub 2 O sub 3 provides a unique contribution to improvements in the leach resistance of these complex glasses. Both glass compositions studied are compatible with the low melting temperature, <1150 exp 0 C, required for the French AVM Process. The quantity of simulated waste products is 9%, characteristic of the Swedish nuclear waste program. (Atomindex citation 13:696945)