Numerical analysis of permafrost heat transfer for small module reactor installation in northern areas

Abstract

Permafrost degradation amplified by climate change is one of the key issues to consider when attempting to install a small modular reactor (SMR) in remote towns and communities of northern Canada. If the thermal disturbance of permafrost occurs, the ground's strength may be significantly 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, including 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), to predict the ground temperature variation with depth. The model was assessed by comparing against the available analytical solutions, and then applied to an underground SMR structure (using the Russian-ELENA design) and a civic building foundation (Igloo Church in Inuvik) to forecast the influence of construction heating and seasonal change on the thawing fronts, especially below the structure foundations. The climate data of Inuvik, Northwest Territories, Canada was used as typical weather conditions of northern areas. The numerical results concluded that there is no significant difference of the thawing front penerations adjacent to the underground SMR structure between the summer and winter times, except the active layer. This study will help to ensure the long-term performance of SMR structures under changing environmental conditions.

Keywords

• SMR installation
• Northern permafrost conditions
• Heat transfer
• Geothermal analyses
• Foundation stability