BGR-Beiträge zu der BGE-Veranstaltung
„Tage der Standortauswahl“ vom 08.–10.06.2022
Themengebiet: „THMC gekopptelte Prozesse und Sicherheitsanalysen“
Which impact do large inhomogeneities have on the host rock integrity? - Preliminary THM results for a generic clay rock-site in northern Germany
T. Tran, V. Kumar, M. Bittens, J. Maßmann, J. Thiedau (Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover)
Abstract:
A safety assessment methodology for repositories in clay rock has been developed in the ANSICHT-I project. In the ANSICHT-II project, carried out by BGE-TECHNOLOGY, Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) and BGR, a generic geological argillaceous site is used to demonstrate and verify the methodology. One of BGR’s focal points here are numerical calculations to analyse the integrity of the geological barrier based on legal requirements.
Therefore, detailed numerical analyses are conducted.
Discrete inhomogeneities such as sand lenses, concretions and cementitious structures are caused due to natural processes that occurred during clay rock genesis. To analyse their impact, different generic scenarios are simulated. The parametrization of those structures is generic but based on observations on meter to km-scale in clay rock. The influence of the inhomogeneities on the fulfilment of the integrity-criteria for clay rock is studied by comparative numerical analyses. In this contribution, the open-source-code OpenGeoSys 6 is used for thermo-hydro-mechanically (THM) coupled simulations. Exemplary results of inhomogeneous scenarios are compared against a homogeneous reference scenario. The comparison of the generic scenarios should improve the understanding of the influence of inhomogeneities on the integrity of the host rock. The findings help to evaluate the developed safety assessment methodology in the context of discrete natural inhomogeneities. This helps to identify possible areas of model and methodology development.
