2012:41 Technical Note, Hydrogeological conditions at the Forsmark site

The hydrogeological site description and groundwater models employed in support of SR-Site, in many ways, represent advances in the state of the art for crystalline bedrock where groundwater moves mainly through fractures. Advanced methods are used for representing water-conducting natural features on scales from kilometres down to a meter, as well as excavated portions of the repository including backfilled tunnels and deposition holes.

The models used include representations of key physical processes that could affect groundwater flow, including changes in shoreline location, density-dependent flow, mixing of waters of different salinity, and temperature effects including formation of permafrost during future colder climates. Model variants and stochastic simulations are used to explore most of the key uncertainties that can be identified at this stage.

The hydrogeological analysis thus covers many of the issues that are of concern for safety assessment, in terms of affecting the safety functions that have been identified for SR-Site. However, there are still some gaps that should be resolved as part of the main review phase.