Study of the impact of coatings on the aging assessment of double wall concrete containment building without metallic liner

EDF’s long-term energy strategy involves extending the lifetime of its nuclear reactors, potentially beyond 60 years. A key element in this objective is ensuring the durability of the concrete containment building (CCB), which is essential for reactor safety. While most ageing studies focus on concrete and steel, the role of surface coatings is often neglected. These coatings, applied to limit leakage, significantly affect the drying process by acting as moisture barriers. This reduces drying shrinkage and creep, which are key contributors to long-term deformation. This study evaluates the impact of coatings on the CCB through a comparative numerical analysis. Two configurations were considered: one not accounting for coatings in its model and one modeling them. Thermo-hydric simulations providing temperature and moisture fields up to the 8th ten-yearly inspection on the CCB (VD8) were used in long-term mechanical computations. The results show that coatings can reduce drying rates, tensile stresses, and creep-related deformations, leading to a more stable long-term behavior of the containment.