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Abstract

The leaching performance of pressureless sintered SYNROC crystalline ceramic waste forms containing simulated high-level radioactive waste has been evaluated under different leach conditions and temperatures. The leach solutions were analysed to determine the concentrations of the simulated waste elements and matrix components released into the leachants. The leach rates of Ba and Ca were in the range of 0.1 to 0.02g/(m(2).d) after one week of leaching in deionized water at 150 C. No significant difference in the leach behaviour of SYNROC was observed in distilled water and in simulated brine. Rutherford backscattering spectrometry and secondary ion mass spectrometry analyses revealed the existence of near-surface layers enriched in Ti and depleted in Ba and Ca. These act as a protective encapsulant decreasing further leaching. Elastic recoil deflection analysis showed the existence of hydrated surface layers on the leached SYNROC which were much thinner than those observed in parallel work with borosilicate waste glasses. Radiation damage produced by ion implantation increased the otherwise very small leach rates of SYNROC. At high damage levels, SYNROC was shown to become amorphous (metamict).

Additional information

Authors: SOLOMAH A G, Institut fur Chemische Technologie, Kernforschungsanlage Julich (DE);MATZKE H J, JRC Karlsruhe Estab. (DE)
Bibliographic Reference: Paper presented: 12th International Symposium on the Scientific Basis for Nuclear Waste Management, Berlin (DE), Oct. 10-13, 1988
Availability: Available from (1) as Paper EN 34396 ORA
Record Number: 198910174 / Last updated on: 1994-12-01
Category: PUBLICATION
Original language: en
Available languages: en