English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

. The disposal of heat-generating nuclear waste in deep geological formations is an internationallyaccepted concept. Several repository systems are under discussion in Germany, whereby claystone, saltor crystalline rock could act as the host rock. In this contribution we focus on repository systems where theContainment Providing Rock Zone (CRZ) ensures safe enclosure of the waste and thus the geologic barrier isessential. Even though the various rock types considered differ substantially in their mechanical, hydraulic, thermaland chemical behavior, they must all meet the same safety requirements as defined by the German FederalMinistry for the Environment, Nature Conservation and Nuclear Safety (BMU) in 2020. As part of thesesafety requirements, it must be shown that the integrity of the CRZ is guaranteed for the verification period, i.e.the retention of the properties essential for the containment capacities must be demonstrated over 1 million years.Therefore, the formation of new pathways must be avoided and temperature development must not significantlyimpair the barrier effect. The anticipated stresses and fluid pressures should not exceed the dilatancy strengthand the fluid pressure capacity, respectively. In order to assess the compliance of these requirements, numericalmodelling is an essential and powerful tool. Even though great progress has been made regarding the efficiency of computationalmethods, multiphysical modelling on different length scales over long time periods is still a challenging task. Moreover, since readilyavailable solutions do not exist, adapted methods have to be developed and evaluated, in order to verify concepts and numericalimplementations. The BGR gained experience in the field of thermal, hydraulic, mechanical (THM) numerical analysis of the integrity of the CRZ in salt rockand clay stone joined research projects on German disposal options. For crystalline rocks, first concepts are currently being developedwithin the CHRISTA II project. Compared to clay stone and salt rock, special features have to be taken into account: First of all, crystallinerock is characterized by fractures and other discontinuities. Thus, it cannot be assumed that an undisturbedarea of sufficient size can be found for the entire nuclear waste. Consequently, several smaller CRZs must bedefined, each providing undisturbed rock. Numerical analysis must deal with smaller CRZs and mechanical andhydraulic boundary conditions that are influenced by fractures. In addition, the processes in the individual CRZsmay influence each other (e.g. Temperature distribution). Preliminary modelling approaches and results of numerical THM analyses,considering an upscaled fracture network, are presented.

Numerical Analysis of the integrity of potential host rocks – modelling thermo-hydro-mechanical processes in the containment providing rock zone