Updated State of the Art on the assessment of the chemical evolution of ILW and HLW disposal cells: EURAD-ACED Deliverable 2.2

The broader scope of the work package ACED is the assessment of the chemical evolution at the disposal cell scale involving interacting materials and thermal, hydraulic and/or chemical gradients by considering Intermediate Level Waste (ILW) and High Level Waste (HLW) disposal concepts. These concepts are representative for Europe. HLW and ILW disposal cells in granitic and clay host rocks are studied in ACED. Disposal of this waste is foreseen in geological disposal facilities at a sufficient large depth to minimize the impact of climate change on the chemical evolution of these disposal cells. The waste is removed from the immediate human and dynamic, natural surface environment and the stable geological deep environment provides predictable conditions for the chemical evolution of the materials within these disposal cells. A key feature in the chemical evolution of disposal cells in the post-closure phase is the availability of water. Construction and operation can have an important influence on this availability, especially for disposal cells in indurated clays. The focus of this report is to give an update of the state-of-the-art by highlighting the main insights obtained in ACED.