oa The Influence of Climate Changes on the Safety of Geological Repository in the Crystalline Rocks of the Chornobyl Exclusion Zone

The paper presents the results of modeling possible trends in the influence of future climate changes on the safety of a geological repository of radioactive waste for the case of its placement in the crystalline rocks of the Chornobyl Exclusion Zone.

Assessment of the potential impact of future climate changes on the safety of a DGR is one of the mandatory components of the its safety case. The climate changes within ChEZ territory can led to the formation glacial lakes, the manifestation of glacial dislocations, catastrophic floods and the formation of glacial erosion.

A two-dimensional finite-difference filtration-transport model was used to perform climate impact investigations. The model simulates a vertical section of a typical geological section of the ChEZ. The results of separate model calculations are an estimate of the time of movement of the pollutant from the repository to the groundwater discharge zones and the pollutant concentration in those zones.

A set of modeling scenarios included the studying of such phenomena impact as: temperate climate, desert, glacier cover, near-glacial lake, permafrost, regional flow changes. A separate scenario is described by changing one of the model parameters (with the rest unchanged). The scenario consists of several calculations and allows to assess the impact of changing the model parameters on the time and intensity of pollutant transport.

On the base of simulation results were drawn the following conclusions.

Climate changes will lead to the emergence of certain phenomena and processes at the repository site that will affect the safety of the geological repository. The safety of the DGR in crystalline rocks of the ChEZ will be positively affected by: decrease in the annual amount of precipitation; formation of a surface lake on the repository site. The following will have a negative impact on the repository safety: the advance of the glacier with the passage of its marginal part through the repository site, or the formation of a glacial dam next to the site, which holds the glacial lake; formation of mosaic permafrost; an increase in the regional flow of groundwater through the zone of repository placement.

The obtained results will be used in the future for development of site selection criteria and development of safety case for DGR in crystalline rocks of the ChEZ.