Development of Permafrost Heat Transfer Model for SMR Concrete Structure Stability Analysis

Abstract

When planning for the installation of a small modular reactor (SMR) in Canadian northern areas, permafrost degradation, which can occur due to climate change and plant operation, is one of the key issues to consider. If thermal disturbance of permafrost takes place, the strength of the ground may be reduced, resulting in structural settlement and stability problems. Therefore, when constructing an SMR on permafrost soils or bedrocks, local permafrost conditions must be protected around the foundations. In the present work, a permafrost heat transfer model has been developed, which included the mechanisms of the transient heat conduction, convection and phase change between the solid (ice) and liquid (water) in a porous medium (subsurface soil or sand). Based on Global First Power (GFP) micro- modular reactor (MMR) design, the heat transfer between the underground concrete structure and adjacent ground soil was simulated to predict the ground temperature variation with depth. The climate data of Inuvik, Northwest Territories, was used as typical weather conditions of Canadian northern areas. The simulation results are used to evaluate the influence of plant operational heating and seasonal changes to the thawing fronts, especially below the structure foundations. This study will provide the temperature information for the structural analysis of concrete components to ensure the long-term performance of SMR structures under changing environmental conditions.