Abstract. This contributed poster shows the current state of development of a finite
element implementation as part of an open source software library (OSSL) for
the simulation of thermo-hydro-mechanical (THM) coupled processes. The
reliable handling of numerical methods is fundamental for the understanding of
scientific interrelationships and thus, a crucial prerequisite for modeling
THM scenarios, as well as for the understanding and evaluation of preliminary
safety investigations during the site selection process for the storage of
high-level radioactive waste. There are several motivations for developing an
in-house OSSL, which will allow us to:
Build capacity and maintenance within BASE (Federal Office for the Safety of Nuclear Waste Management) regarding issues of the numerical modeling of safety-relevant aspects on the long-term safety analyses specified by the German legislator in the site selection process. Develop a collection of known benchmarks and evaluation examples for the comparison of different software tools, applying a uniform interface to simplify the use of the available highly specialized open source codes. Diversify the testing possibilities regarding the preliminary safety investigations by means of our own, independent modeling software. Document basic THM scenarios for internal or, if necessary, public technical training, e.g., density-driven fluid flow (Fig. 1), convergence in salt, temperature propagation in the repository area, crack development, diffusive or advective mass transport. Ensure transparency and, in principle, might allow for appropriately proven-quality (validated) and documented simulation tools for the public regarding questions about the preliminary safety investigations during the site selection process. The development of the OSSL is mainly based on the scripting language Python,
which allows the necessary flexibility for the diverse fields of application
and at the same time enables maximum transparency for all aspects of the
source code. To ensure the high quality of the software, state of the art
development tools are used (e.g., version control, automated tests, and
documentation generation). Figure 1 shows our preliminary simulation results of the so-called Elder
problem (Elder, 1967), a popular standard benchmark for thermo-hydrogeological
coupling in which fluid motion in a porous medium is driven by buoyancy
forces.