Developing hydrogeological conceptual models for a nuclear waste disposal site

ESI has been involved with developing the hydrogeological conceptual model at a low level waste disposal site over many years.  An understanding of the hydrogeology is required in order to support risk assessments which consider contaminant transport within the groundwater system.  The site has a large number of groundwater and surface water monitoring points and many studies have been carried out at the site over many years, both directly to support the site hydrogeological understanding and for research purposes.  The first step in developing the model was to compile all this information.  Data were entered into a custom built database and reported through an electronic report management system.  Following a review of this information, an initial conceptual model was developed which identified certain data gaps.  A site investigation programme was then undertaken to acquire the necessary data and the conceptual model was refined.

The conceptual model has been developed in conjunction with numerical groundwater flow and contaminant transport models.  The models have been built based on the conceptual model at the time and the results of the models have been used to help update and refine the conceptual model.  In addition, further site investigations have been undertaken, often for geotechnical engineering purposes.  The information from all of these studies, and from the site monitoring programme, has been fed into the conceptual model as a series of iterative updates.

The conceptual model has been used to support two post closure safety assessments and is currently being refined to support the next assessment.

Please contact ESI (01743 276100 / email) for more information.