(GRS 218) Radionuclide transport and retention in natural rock formations

Deep geological disposal is based on a multi-barrier concept in which clay materials often play an important role as geological barriers. Detailed investigations of suitable geological analogues may lead to a better understanding of the complex interrelationsbetween transport and sorption of radionuclides in argillaceous media under natural conditions, and especially on very long-term scales relevant for Performance assessment (PA).The Ruprechtov site was chosen because its geological and geochemical conditions are similar to sedimentary sequences which cover often potential host rocks for underground waste repositories. It is situated in the north-western part of the CzechRepublic in a Tertiary basin of the Eger (Ohře) rift composed of clay and organic material (coal, lignite), with places of high uranium concentrations. Within a bilateral project this site has been investigated by GRS, Germany and NRI, Czech Republic inorder to identify the main mobilisation/immobilisation processes for PA-relevant elements, namely uranium.