Investigation of inorganic colloids in the near-field of a waste repository

The major concern in nuclear waste management is its safe disposal. Models are used to predict the long-term fate and mobility of radionuclides and other contaminants through the environment. Information from these models is used to assess the long-term safety of a waste disposal site. To accurately predict the fate of contaminants these models must contain all the parameters that affect contaminant transport through the geosphere. Colloids can be found in all natural surface and ground waters and have large surface areas onto which contaminants can sorb. They have been identified as being potentially important in the transport of radionuclides in groundwater and could significantly affect any performance assessment of a repository. Colloid mediated transport is generally not included in the predictive models although their influence could be significant. This report describes firstly the results of a groundwater sampling campaign undertaken at the Drigg site in Cumbria which focussed on the colloidal content of the waters and their associated radionuclides. [Continues.]