Regional Scale HPC Reactive Transport Simulation of Nuclear Spent Fuel Repository in Forsmark, Sweden

The future nuclear spent fuel repository in the Forsmark area in Sweden, constructed at a depth of 500 meters, is designed to be isolated from people and nature for at least 100.000 years. As part of the safety assessment of the repository, it is necessary to simulate the interaction of the repository compounds with the surrounding groundwater and rock. To evaluate the geochemical evolution in the region under sealed repository conditions, a HPC framework, which couples a groundwater flow simulator (DarcyTools) optimized for fractured rock hydrology and a high performance reactive transport code (PFlotran) was developed. The migration of a hyper-alkaline plume (high pH plume) over 10.000 years is simulated in a large scale 3D model (100 Million cells). The results show the control of the rock fractures in the movement of the reactive plume.