The Impact of cement on argillaceous rocks in radioactive waste disposal systems; An Overview of research needs, and ongoing work being undertaken in Japan

Wilson, J.*; Bateman, K.*; 川間 大介*; 舘 幸男

no journal, , 

Several repository concepts have been proposed for the disposal of radioactive wastes, some of which include argillaceous (clay-rich) host rocks and cementitious engineered barriers. The presence of hyperalkaline cement pore-fluid results in the destabilization of primary minerals in argillaceous rocks, leading to alteration at the interface between cement/concrete and repository host rock. This phenomenon has implications for radionuclide transport and safety assessment. A general review of key data on cement-mudrock interactions has been undertaken as part of a programme of research in Japan, with experimental, analogue, and modelling studies being considered. Although a reasonably good understanding of the key processes has been acquired, with expected features of cement-mudrock interfaces being identified, there are some areas in which a degree of uncertainty remains. These include alteration under elevated temperature conditions, the kinetics of secondary mineral growth, the extent of pore clogging, and radionuclide mobility. In addition to the recent review, work is being undertaken in Japan to further the understanding of cement-mudrock interactions, including: in situ experiments, laboratory experiments, and their simulation. This work demonstrates the progress made within the Japanese programme and suggests areas where further work may be beneficial.