Typical Modeling Activities

At the start of the project in 1992, it was decided to study a number of benchmark tests (BMT) and test cases (TC) of importance to radioactive waste disposal. This strategy has been followed throughout the duration of the project. The BMTs investigate hypothetical problems in the behavior of individual or coupled THM and THMC processes, and analyze the extrapolations of results over the large temporal and spatial scales of interest to repository performance. The TCs are actual laboratory and field experiments studied and modeled to advance our understanding of the THM and THMC processes. In this case, numerical modeling can assist both to interpret the test results and to test the models used. A number of large-scale, multiyear field experiments have been studied within the project [e.g. the Kamaishi T-H-M Experiment, FEBEX, and the Yucca Mountain drift scale heater test (DST)].

BMTs and TCs are collectively studied and modeled by DECOVALEX participants. As modeling teams provide their individual results for the same modeling challenge, comparative assessment can assist both to interpret the test results and to test the simulation models used. While code verification and benchmarking efforts have been undertaken elsewhere to test simulation codes, the model comparison conducted within the DECOVALEX framework is different because (a) the modeling tasks are often actual laboratory and field experiments, and (b) DECOVALEX engages model comparison in a broad and comprehensive sense, including the modelers’ choice of interpretation experimental data, boundary conditions, rock and fluid properties, etc., in addition to their choice of coupling schemes and simulator. Based on the results from these studies, new model capability developments may be undertaken and new experiments be proposed to support model development and to advance the state of mathematical modeling for coupled processes in fractured rocks and buffer materials.