Hydrological and hydrogeological modelling of radioactive waste deposit

After conducting site investigations for construction of the repository for nuclear waste at two potential sites, The Swedish Company SKB decided in June 2009 to submit an application for the siting of repository at Forsmark, Osthammar Municipality. The used fuel will be encapsulated in copper and then placed in the bedrock at a depth of 500 meters, and surrounded by bentonite clay.

MIKE SHE was used describe the hydrological and near-surface hydrogeological conditions at Forsmark and the contact between surface water and groundwater. Data from extensive site investigations were the basis for calibration of the integrated surface water groundwater model. The simulations included water movement as well as transport and diffusion using particle tracking and with advection-dispersions sub-models.

The modeling has significantly enhanced the understanding of the complex dynamics between surface water and groundwater in different layers and the contact between soil and rock at Forsmark and used to analyse potential future conditions in the area. Predictions were carried out 3000 to 8000 years into the future, with respect to uplift (change in geology); change in vegetation and soil cover; and extreme climatic conditions including permafrost conditions and extreme wet conditions.