Geological disposal of higher-activity radioactive waste, by placing it deep underground within a stable geological environment, is internationally recognised as the safest long-term solution. Among the host rocks being considered for a Geological Disposal Facility (GDF), clay-rich mudstones are particularly of interest because of their exceptionally low permeability and their ability to self-seal around engineered excavations.
Yet a fundamental challenge remains which is how much does excavation disturb the surrounding rock, and how does the migration of fluid impact by the disturbed rock over the long timescales relevant to radioactive waste disposal? This remains an area of uncertainty.
Addressing questions such as these requires collaboration across disciplines and sectors. Against this backdrop, funding awarded through an EPSRC Impact Acceleration Account (IAA), enabled us to host a technical workshop, leveraging expertise being developed at the University on excavation damaged zone (EDZ) evolution. The workshop, entitled Understanding and Quantifying Excavation Damage and Fluid Flow in Mudstone Host Rocks for Geological Disposal Facilities (GDFs), was held in March 2026.
This workshop came at a particularly important time, because the UK is exploring, for the first time, the Mercia Mudstone as a host rock for deep geological disposal of its high-level radioactive waste. Consequently, there is an increasing need to translate laboratory- and field-scale measurements of rock properties into robust predictions of how excavations associated with the construction, operation and post-closure of a GDF will behave hundreds of metres below ground. Such understanding is critical for reducing uncertainty and thereby underpinning a robust safety case. Bridging the gap between fundamental research and practical application was the central aim of the event.
