Nuclear Technology / Volume 174 / Number 1 / April 2011 / Pages 94-108
Technical Paper / Geochemistry and Ground Transport of RW
The study presented in this paper examines the potential of extruded bentonite as an additional barrier to radionuclide release to the far field. In the saturated repository, the bulk bentonite buffer surrounding the waste package will extrude into an intersecting fracture. Subsequent radionuclide release and transport into the fracture could be affected by the presence of this extrusion region. A model was previously established to describe the transport of radionuclides in the fracture that also includes this extruded bentonite. In this paper, we study model simulations for an idealized case of cesium transport through the extrusion region at elevated temperature. Extrusion speed will increase and cesium transport is enhanced with temperature; however, this extrusion region shows favorable performance in confining cesium at all temperatures. This study suggests that additional, rigorous modeling of this extrusion region as a barrier to radionuclide release with consideration of performance assessment studies is warranted.