Interaction Experiment At The Bukov URF

Abstract

The Interaction Experiment is being prepared by the CTU, ÚJV and ČGS for SÚRAO at the Bukov URF.The experiment is concerned with the study of mutual interactions between the candidate materials for the engineered barriers of the DGR, the rock environment and groundwater.The objective is to investigate the various interactions between the materials planned for use in the future DGR in a real rock environment.Thus,the experiment is located in the Bukov URF at a depth of 550m of the former Rožná I mine. The experiment consists of ten physical models emplaced in horizontal boreholes.Five of the models have been designed for the study of interactions at ambient temperatures and the other five for the study of interactions at elevated temperatures (4x up to 100°C, 1x up to 200°C).Heated models are cylindrical in shape with a diameter of 240mm and a length of 1450mm.Rod heaters have been placed along the axes of each of the models.The heaters are surrounded by a bentonite filling and geotextile or concrete rings have been placed along the interface between the bentonite layer and the rock so as to provide for the homogeneous influx of water. Other models have a diameter of 90mm and do not contain heaters.All the models are being artificially saturated with local groundwater. In order to investigate the various types of interactions,differing combinations of materials were selected for each model:compacted bentonite with two differing dry densities,a bentonite pellet mixture,standard concrete and low pH concrete.All the materials as well as the rock environment were characterized in detail.It is assumed that the loading phase for each of the physical models will last for at least 3 years.Following the completion of the experiments, the individual physical models will be dismantled and analysed in detail.The outcome of the experiment will consist of a detailed description of the geochemical and mineralogical changes to the various materials.