Enhanced Sealing Project (ESP): evolution of a full-sized bentonite and concrete shaft seal
Published:January 01, 2014
D. A. Dixon, D. G. Priyanto, J. B. Martino, M. De Combarieu, R. Johansson, P. Korkeakoski, J. Villagran, 2014. "Enhanced Sealing Project (ESP): evolution of a full-sized bentonite and concrete shaft seal", Clays in Natural and Engineered Barriers for Radioactive Waste Confinement, S. Norris, J. Bruno, M. Cathelineau, P. Delage, C. Fairhurst, E. C. Gaucher, E. H. Höhn, A. Kalinichev, P. Lalieux, P. Sellin
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A full-scale shaft seal was designed and installed in the 5 m-diameter access shaft at Atomic Energy of Canada Limited’s (AECL’s) Underground Research Laboratory at the point where the shaft intersects an ancient water-bearing, low-angle thrust fault at a depth of c. 275 m in granitic rock. The seal consists of a 6 m-thick bentonite-based component sandwiched between 3 m-thick, keyed upper and lower concrete components. This design was adopted in order to limit the mixing of saline groundwater from the deeper regime with the fresher, near-surface groundwater regime. Construction of the shaft seal was done as part of Canada’s Nuclear Legacy Liabilities Program. A jointly funded monitoring project, called the Enhanced Sealing Project (ESP), was developed by AECL (Canada) and jointly funded by NWMO (Canada), SKB (Sweden), Posiva Oy (Finland), and ANDRA (France), and since mid 2009 the thermal, hydraulic and mechanical evolution of the seal has been constantly monitored. The evolution of the type of seal being monitored in the ESP is of relevance to repository closure planning by demonstrating the functionality of shaft seals. Although constructed in a crystalline rock medium, the results of the ESP are relevant to the performance of seals in a variety of host rock types.
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Clays in Natural and Engineered Barriers for Radioactive Waste Confinement
This Special Publication contains 43 scientific studies presented at the 5th conference on ‘Clays in natural and engineered barriers for radioactive waste confinement’ held in Montpellier, France in 2012. The conference and this resulting volume cover all the aspects of clay characterization and behaviour considered at various temporal and spatial scales relevant to the confinement of radionuclides in clay, from basic phenomenological process descriptions to the global understanding of performance and safety at repository and geological scales. Special emphasis has been given to the modelling of processes occurring at the mineralogical level within the clay barriers.
The papers in this Special Publication consider research into argillaceous media under the following topic areas: large-scale geological characterization; clay-based concept/large-scale experiments; hydrodynamical modelling; geochemistry; geomechanics; mass transfer/gas transfer; mass transfer mechanisms.
The collection of different topics presented in this Special Publication demonstrates the diversity of geological repository research.