Long-term mechanical analysis of nuclear reactor containments

The report presents results of a benchmark, Vercors 2022, which Electricité de France organised. A multiphysics mathematical model has been developed applied to predict the long-term mechanical behaviour of a reactor containment. In addition, a leakage model has been developed that estimates the air leakage through a reactor containment when a pressure test is performed. The model is available to both designers and researchers. Many different parameters that give rise to deformations are included in the model like, temperature and moisture variations, pre-stressed tendons and creep according to Eurocode 2.

This analysis shows that the presented model underestimated the long-term deformations evaluated when compared with the actual observations at many of the analysed points. This underestimation applies to all examined structural components such as cylinder wall, gusset, dome, and raft structure.

The leakage model presented in this report is relatively simple yet provides a reasonably good agreement with measurements. It takes into account that air density varies with pressure and that the concrete air permeability increases at it dries.