Engineering Challenges in the Geological Disposal of Radioactive Waste and Carbon Dioxide

This chapter deals with engineering issues related to the geological disposal of radioactive waste (RW) and carbon dioxide (CO2). An overview of the methodology for tackling these challenges is given, starting from the understanding of the geological context and the rock characterization (in laboratory and in situ) to the design and construction of the depository.

We recall first the fundamentals of porous media and the transport mechanisms of solutes and gas in geological formations. Then we describe the various steps in the engineering design of underground workings, from site investigation to long-term safety and performance assessment. The particular cases of RW and CO2 disposal are developed independently. Finally, we compare both types of disposal from the engineering point of view and show that, even if obvious differences exist, some requirements are similar. It is therefore valuable to develop a comparative view of the two approaches in order to benefit from acquired experiences.