Project information


The BIGRAD consortium integrates the skills of leading researchers from several Universities and Research Organisations. These are the Universities of Manchester, Leeds, Sheffield, and Loughborough, the British Geological Survey (BGS), the German Institut für Nukleare Entsorgung (INE),the Diamond Light Source, and UK National Nuclear Laboratory (NNL). In addition, we have members of the Nuclear Decommissioning Authority (NDA), the Environment Agency, the Paul Scherrer Institute (PSI), and ANDRA who act in an advisory role to the consortium.

SCIENTIFIC THEME: 

The UK Government will now dispose of higher activity radioactive wastes in a Geological Disposal Facility (GDF) (DEFRA, 2008). A GDF will be a deep subsurface engineered facility in rock that will receive radioactive wastes that have been conditioned for disposal. Intermediate level waste (ILW) is the largest volume of radioactive waste that will be disposed in the subsurface and the current generic concept for ILW involves conditioning by grouting in stainless steel drums, storage and ultimately emplacement into the GDF during its operational period. After the GDF has been operational for several decades and has received the radioactive wastes destined for disposal, it is anticipated that the facility will be backfilled with cement, thereby sealing the subsurface and allowing resaturation. The presence of iron metal from waste-forms and from engineering iron will produce reducing conditions in the subsurface. In addition, during resaturation the cement backfill will react to generate hyperalkaline groundwaters. The reducing and alkaline conditions are intended to reduce radionuclide solubility. However, the steep biogeochemical gradients that will undoubtedly develop across the interface between the GDF and the surrounding host geology are poorly understood and are likely to be critical controls on radionuclide solubility and transport from the GDF. It is this Chemically Disturbed Zone (CDZ) that is the focus of the BIGRAD Consortium.


KEY OBJECTIVES:

 The BIGRAD consortium has two overarching objectives:

- To gain a mechanistic understanding of biogeochemical processes and their controls on radionuclide behaviour in the CDZ;

- To develop predictive modelling capability, firmly rooted in scientific advances and experimental results, to quantify radionuclide mobility in the CDZ.

 

WORKPACKAGES:

BIGRAD is organised into three interlinked work packages (see Figure, right):


Work package 1 (WP1) concerns geosphere evolution around a GDF and is managed by Dr. Sam Shaw

Work package 2 (WP2) investigates radionuclide form, reaction, and transport in an evolving CDZ environment and is managed by Dr. Nick Bryan.

Work package 3 (WP3) encompasses the synthesis and application of WP1 and WP2 to GDF performance assessment and is managed by Dr. Joe Small. 


CROSS CUTTING THEMES:

In addition the consortium integrates two key areas via cross cutting themes in:

Theme 1 - Biogeochemical processes in the chemically disturbed zone managed by Prof. Jon Lloyd.

Theme 2 - Predictive modelling managed by Dr. Steve Thornton.