SSM has been following the investigations of the two candidate sites for a repository for spent nuclear fuel that the Swedish Nuclear Fuel and Waste Management Company (SKB) have been undertaking. SKB has reported the results of the investigations as site descriptive models. These models will be used to underpin the safety analysis following the license application of the repository planned by SKB. One important aspect in the safety analysis is the water flow to, around, and from the repository. In order to model these, discrete fracture network (DFN) models can be used. Such models can capture the stochastic nature and complexity of the hydrologeologic situation at a site.
SSM has funded Clearwater Hardrock Consulting to investigate flow around the planned repository in Forsmark using a DFN model especially designed for this task. In addition, deposition hole utilisation factors have been quantified. The results are considered to be useful for SSM as independent estimates that may be compared to SKB’s results in the up-coming license application. Moreover, the results can be used as a baseline for comparisons to other model variants or alternative models that may be investigated.