Numerical Modelling of Permafrost Protection around Steel-Concrete Composite Wall for SMR Applications

Abstract

Steel-concrete (SC) composite walls are being considered as an alternative to conventional reinforced- concrete (RC) walls for small modular reactor (SMR) structures because of their potential impact on reducing the construction schedule through modularization. When planning for the installation of an 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, local permafrost conditions around the foundations must be protected by insulation, ventilation, or refrigeration systems, e.g., by using freezing pipes, when constructing SMRs in such areas. In the present work, the permafrost heat transfer between the underground SC wall and adjacent ground soil was simulated to predict the ground temperature variation with depth for an annual freeze and thaw process. The climate data of Inuvik, Northwest Territories, was used as typical weather conditions of Canadian northern areas. The simulation result shows that the freezing pipe has a significant effect on the thawing fronts with the influence of plant operational heating and seasonal changes. This study will provide the temperature information for the structural analysis of concrete components and surroundings to ensure the long-term performance of SMR structures under changing environmental conditions.