Multi-disciplinary experimental and theoretical research on the environmental geochemistry of repository systems are being performed in LES, in particular as a scientific contribution to the radioactive waste management programme in Switzerland, however with notable application to other disposal systems. The concept of Switzerland for the management of radioactive waste foresees two types of deep-mined geological repositories: The first is a repository for high-level and long-lived medium-level wastes as well as spent fuel while the second repository type is for low-level and short-lived medium-level wastes.

LES carries out research on various aspects of the near-field geochemistry with the aim of underpinning the safety case and further elaborating the scientific basis for deep geological disposal of radioactive waste. Recent and ongoing research has focused on mineral transformations and the evolution of the barrier system at the interface between a cementitous near field and the host rock (Opalinus Clay), modelling of the long-term evolution of an engineered gas transport system and the interaction of cementitious liner with the bentonite backfill, assessment of the chemical reactions in cement-stabilized waste packages, interaction of the various waste components with each other, assessment of the long-term fate of waste sorts in a cementitious near field on the basis of thermodynamic modeling and immobilization of radionuclides in the anionic chemical form by cementitious materials in reducing conditions.