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What are the impacts of heat producing wastes in a geological repository on the groundwater system? Heat produced by spent fuel causes a significant rise in temperature in a geological waste repository. Even though the heat emission from these wastes diminishes significantly within a few decades, the surrounding groundwater system may be strongly affected for several millennia. The parameter study conducted in co-operation with international research institutes involved numerical simulations of the relevant processes (see figure).
The simulations evaluated the influence of heat producing wastes in a repository at a depth of 300 m below groundlevel on the surrounding partially saturated environment. The figure shows the spatial distribution of temperature, liquid saturation, as well as groundwater- and gas flow velocity 100 years after deposition. The high temperatures cause the water to go from the liquid to the gaseous phase in the immediate surroundings. It then condensates in cooler regions at some distance. Accordingly, the groundwater bypasses the repository. Olivier Jaquet - Groundwater Protection and Waste Disposal Rehabilitation and Renovation Weir Walliswil / CH The existing and manually operated intake at the Roth channel in Murg, Canton Aargau/Bern, is being completely rehabilitated resp. renovated. The old steel flood gates will be replaced by two inflatable weirs (width: 2 x 9.0 m, height: 0.70 m). The existing intake will be demolished and reconstructed. In connection with the renovation of the Weir Walliswil, the Roth Channel intake will be supplied with a fish ladder and a minimal discharge of 440 l/s, as the law required. With an approximate length of 220 m length the fishpass will connect the tailwater of the river Murg with the head water. The regulation of the water discharge will be regulated by a double vertical gate at the intake construction, 100 m upstream of the weir site.
The renovation work for the rehabilitation of the Weir-Walliswil and the fishladder started in April 2001. At the beginning of July 2001 the Roth Channel will resume normal operation. The project will be terminated in August 2001. Felix Hansmann - Hydropower Plants |
