Nuclear

Many countries, including the UK, retain nuclear waste created during decades of nuclear power generation and nuclear fuel reprocessing.

Most plan to store the higher grades of waste in sealed containers within deep geological disposal facilities (GDFs) over very long timescales, until it decays and becomes less harmful. GDFs need to meet strict criteria, including low permeability of the host rock, protection against groundwater contamination, and long-term mechanical, physical and chemical stability. Suitable sites are usually within granite/gneiss, salt and shale formations. 

Decaying heat from the radioactive waste will affect temperatures within and around a GDF, depending on the type of waste involved, the container and backfill material, and the host rock properties. Chemical changes can be caused by cementitious backfill materials used for sealing of the nuclear waste package and tunnels, which, if not monitored, can cause a –build-up of stress leading to fractures in the GDF. 

Detailed site investigations must include descriptive models of the initial state of variables such as geology, hydrogeology, hydro-geochemical features, and mechanical and thermal gas transportation factors.

The combined expertise of geochemical and geomechanical researchers at Leeds is helping to identify suitable sites for GDFs, and helping to understand and monitor possible thermal and chemical changes over the longer term.