Hydro-geology systems

The bathtub effect occurs, in part, because most wastes have much higher hydraulic conductivities than the natural material into which they are placed they may also have very different unsaturated soil—moisture characteristics. The hydraulic conductivity of some wastes can be reduced by compaction. The bathtub effect also occurs because more infiltration enters the disposal excavation than would under normal undisturbed conditions. Trench covers may be constructed to achieve the desired hydraulic conductivity and to limit infiltration for the required period of containment or until compaction of the wastes occurs however, it is difficult to maintain the trench covers. The covers must withstand attack by plants, weather (freeze—thaw, wet—dry), erosion, and strains caused by consolidation within the trench. Most trench covers are not capable of meeting these demanding requirements without costly long-term maintenance programs. The cover should be designed to allow for expected consolidation and to utilize hydro-geological concepts of saturated and unsaturated flow systems present at the site. 

Hannington, M.D., de Ronde, C.E.J., and Petersen, S., 2005. Sea-floor tectonics and submarine hydro-thermal systems. 100" Anniversary Volume of Economic Geology (in press). 

Simmons, S. F., Brown, P. R. L. 2000. Hydro-thermal minerals and precious metals in the Broad-lands-Ohaaki geothermal system Implications for understanding low-sulfidation epithermal environments. Economic Geology and the Bulletin of the Society of Economic Geologists, 95, 971 -999. 

Lilley, M.D., Feely, R.A. and Trefry, J.H. (1995) Chemical and biochemical transformations in hydro-thermal plumes, in Seafloor Hydrothermal Systems, Physical, Chemical, Biological, and Geological Interactions (eds S.E. Humphris, R.A. Zierenberg, L.S. Mullineaux and R.E. Thomsom), Geophysical Monograph 91, pp. 369-391. 

Japan Nuclear Cycle Development Institute (JNC) has already developed the coupled thermo -hydro and mechanical (T-H-M) model and has initiated a research on the coupled T-H-M-C processes to predict the chemical evolution of buffer material and porewater chemistry, and the chemical effects on other (thermal, hydraulic and mechanical) processes. In this research, numerical experiment system for the coupled T-H-M-C processes is developed in order to predict the longterm evolution of the near-field (engineered barriers and surrounding host rock) for various repository designs and geological environments. 

Liu. J, and Brady. B. H., 2003, Simulations of A Coupled Hydro-Chemo-Mechanical System in Rocks, Geotechnical and Geological Engineering, in press (accepted on 11/1/03). 

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