Rolf Christiansson

Thermo-Hydro-Mechanical (T-H-M) Impacts of Glaciation and Implications for Deep Geologic Disposal of Nuclear Waste

Abstract The thermo-hydro-mechanical impacts of extreme climate change on the lithosphere down to depths at which deep repositories might be sited have been simulated. The effects of glaciation, including ice sheet and permafrost development, have been studied using site-specific data by combining four models. A climate model provides the forcing function, and ice sheet, permafrost, and coupled hydromechanical models are used to assess impacts. It is concluded that glaciation occurs on a timescale and has impacts on a depth scale that require it to be analysed in a safety analysis for deep lithosphere disposal of long-lived radionuclides in areas that have been prone to glaciation in the past. The simulations have provided valuable insight about processes and mechanisms likely to influence the long-term performance of a repository, the geosphere, or both. The key impacts are discussed, and appropriate methods identified.

Application of Flac2D to the Temperature Calculation and Approximate Damage Analysis for the Canister Retrieval Test in Sweden

During the period from October 2000 to November 2005, the canister in the CRT deposition hole DD0092G01 was heated with a maximum heat power of 2600W and the temperature and consequently the stress in the surrounding rock volume were elevated. This study investigated if the temperature and possible heat induced damage can be predicted by 2-Dimensional numerical simulations. FLAC2D(5.00) was used to model the excavation and the heating process of the deposition hole. Temperature in the rock was calculated by treating the case either as a horizontal two dimensional or a vertical axisymmetric problem and obtained results were compared with the measured results, whereas stress was calculated from horizontal two dimensional thermal-mechanical coupling analysis and calculated results were applied to approximate damage analysis.