• journal_title：Clay Minerals
• Contributor：W. R. Alexander ; A. E. Milodowski ; A. F. Pitty ; S. M. L. Hardie ; S. J. Kemp ; J. C. Rushton ; Andreas Siathas ; Avrim Siathas ; A. B. Mackenzie ; P. Korkeakoski ; S. Norris ; P. Sellin ; M. Rigas
• Publisher：Mineralogical Society of Great Britain and Ireland
• Date：2013-05-01
• Format：text/html
• Language：en
• Identifier：10.1180/claymin.2013.048.2.06
• journal_abbrev：Clay Minerals
• issn：0009-8558
• volume：48
• issue：2
• firstpage：235
• section：Alteration and migration studies in underground rock laboratories (URLs) and natural analogues

Bentonite is one of the more safety-critical components of the engineered barrier system in the disposal concepts developed for many types of radioactive waste. It is used due to its favourable properties (including plasticity, swelling capacity, colloid filtration, low hydraulic conductivity, high retardation of key radionuclides) and its stability in relevant geological environments. However, bentonite is unstable under alkaline conditions and this has driven interest in low-alkali cements (leachate pH of 10–11). To build a robust safety case, it is important to have supporting natural analogue data to confirm understanding of the likely long-term performance of bentonite. In Cyprus, the presence of natural bentonite in close proximity to natural alkaline groundwaters permits the zones of potential bentonite/alkaline water reaction to be studied as an analogy of the potential reaction zones in the repository. Here, the results indicate minimal volumetric reaction of bentonite, with production of a palygorskite secondary phase.