Summary
The near-field of a nuclear waste repository containing large volumes of cement and concrete will be highly alkaline and, probably, chemically reducing. A challenge in safety analysis is to determine the constraints on releases of particular radionuclides set by their low solubility in such an environment. Chemical thermodynamic models are usually used to calculate such solubilities but these are, inherently, oversimplifications of the real system and must be validated experimentally. These models can also be tested in natural analogue systems. A good analogue of aged concrete pore waters are the hyperalkaline springs found in the region of the Semail Ophiolite Nappe in Northern Oman. These have pH values of 10–12, are somewhat saline and are often extremely reducing, containing significant quantities of free hydrogen gas. In this study, thermodynamic model predictions of trace element solubility limits are compared with actual concentrations measured. Although somewhat crude, results indicate that predicted values are generally consistent with observations and give some indications of over-conservatisms associated with particular databases.
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© 1987 ECSC, EEC, EAEC, Brussels and Luxembourg
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Bath, A.H., Berner, U., Cave, M., McKinley, I.G., Neal, C. (1987). Testing Geochemical Models in a Hyperalkaline Environment. In: Côme, B., Chapman, N.A. (eds) Natural Analogues in Radioactive Waste Disposal. Radioactive Waste Management Series. Springer, Dordrecht. https://doi.org/10.1007/978-94-009-3465-8_17
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DOI: https://doi.org/10.1007/978-94-009-3465-8_17
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