Twenty years of research
For its research on deep disposal, Andra has called on the scientific community in a wide variety of fields (Earth and environmental sciences, chemistry, materials science, applied mathematics, human and social sciences, etc.) through partnerships with research organisations and French higher education institutions. Andra is also very involved in international cooperation, notably with its counterparts abroad, through collaborations or international bodies.
The research conducted over the past 20 years has served to demonstrate the feasibility and safety of deep disposal. Today, this research is helping prepare for Cigeo's construction and operation, as well as its closure and monitoring.
The scientific studies conducted over the past 20 years on the Cigeo project have drawn on complementary approaches and fields. The primary aim of these studies is to acquire the basic information needed to create a strong base for the project's development, particularly:
- the detailed content (chemical and radiological) of the waste packages;
- the basic parameters relating to the radionuclides (e.g. solubility) and repository materials, to be able to then evaluate their behaviour in the repository conditions;
- the properties of the geological medium (such as permeability, the make-up of the water contained in the pores, or thermal conductivity) on different scales (from a centimetre to ten metres) in order to verify its suitability for housing a repository and limiting the transfer of radioactivity;
- the transfer processes of the elements in the materials, geological medium or biosphere, such as diffusion and convection to determine the manner in which these elements are dispersed in the geological medium, in what quantities and over what scales of time and space;
- the dynamics of geological phenomena such as erosion or hydrogeological flows in the layers of the Paris basin to ensure the repository's stability over very long time scales.
These results have been collected by Andra and its scientific partners within the framework of national and international programmes, subjected to peer reviews, published in scientific reviews, presented at conferences and been the subject of theses. In this way, R&D has a valuable role in steering Cigeo's development and supporting its operations. It is used to define the optimal geometry (size, orientation, etc.) for the repository structures, select their design dimensions, and verify that their construction does not alter the confinement properties of the geological medium.
The Cigeo project's transition to an industrial design phase does not mean Andra has any less need to maintain high-level R&D. It needs to provide the supporting scientific and technical elements for the construction licence application, and for the periodic re-assessments that the repository will be required to undergo. More generally, continuing the R&D on radioactive wastes and their conditioning and disposal will contribute to Cigeo's safety and reversibility, and will allow technical and economic improvements to be made over the course of its operating life.