When selecting a site for a deep geological repository it is not only necessary to clearly and credibly demonstrate operational safety covering a period of several decades to hundreds of years, but, long-term safety extending hundreds of thousands of years must be established. The evaluation of deep repository operational safety does not differ significantly from that of the operational safety of existing surface and near-surface repositories; however, the assessment of long-term safety is much more complex and concerns a time horizon comparable with that of the evolution of human kind itself.
A comprehensive safety evaluation requires an understanding of the processes and events that will occur within the storage system. The demonstration of safety for hundreds of thousands of years is possible only by employing a range of mathematical and computational models of the physical-chemical processes which will occur within the repository and its surroundings. The model description of these processes must be based on generally accepted physical laws and the comparison of laboratory data with data obtained from the real environment and that obtained from so-called natural analogues such as the “natural reactor” formed by the Oklo uranium deposit in Gabon, Africa.
The evaluation of safety constitutes one of the main priorities of national deep geological repository research and development programmes. Given that each country has its own specific geological environment, it is not possible to rely entirely on the results of foreign research. It is therefore necessary to evaluate specific locations on an individual site-by-site basis. In order to demonstrate safety, it is necessary to have sufficient knowledge of a large number of scientific fields ranging from geology to applied mathematics.
More information on ensuring the safety of the deep geological repository is available HERE
Medium term plan for the research and development of activities required for DGR siting in Czech Republic in the period 2015 - 2025 is available HERE