Paul Wersin

Reactive‐transport models (RTMs) have been an integral part of the safety case and design optimization for the nuclear waste repository in Finland. Such highly resolved, internally complex RTMs tend to be computationally demanding, thus their design is often a compromise between representativeness and computational efficiency. A modeling strategy is presented, demonstrating how a 2D simplified model can be constructed based upon and calibrated against a geometrically realistic 3D RTM. Key geometrical parameters of the 2D model are consistent with the 3D model, and the 2D model is verified by a series of benchmarks for various designs and conditions of the repository. Overall, the 2D model is proven suitable for fast scoping calculations, as (1) it reduces the mesh elements by 16 times and shortens the run time by about 40 times; (2) it has much more flexible remeshing possibilities; and (3) it provides highly consistent results with the 3D model.