[en] Richard Repository is a near surface underground repository for low and intermediate level radioactive waste of institutional origin. In the course of a joint Phare Project carried out together with the repository operator, the Czech Radioactive Waste Repository Authority (RAWRA), DBE Technology developed a new concept for the closure of individual waste chambers. Main technological element of this concept is the installation of a hydraulic cage around the waste chambers by attaching a gravel layer to all sides of the chamber. This hydraulic cage will prevent the development of advective flow through the waste/concrete body within the backfilled chambers by eliminating the pressure gradient as driving force for such a flow. Thus the transport of radionuclides will be restricted to diffusive fluxes, which results in a considerable decrease of potential radiological impact. In the course of the project the closure of a certain chamber system within the mine was planned up to a grade of detail, which allowed its direct realization as a pilot closure study, which started in the beginning of 2006. (author)