Experimental Design for in situ Characterization of the Callovo-Oxfordian Pore Water Composition at 85 °C

When emplaced into deep geological disposal cells, the high-level radioactive waste packages will induce a transitory temperature increase in the surrounding geological environment. High temperatures will have an influence on the composition of water that will flow into the cells and come in contact with the disposal materials. An in situ experiment which aims at characterizing the Callovo- Oxfordian pore water at 85 °C has been running since 2012. This paper presents the design of the experiment and the predictive thermo-hydro-mechanical (THM) modeling results.