Analysis of long-term behaviour of nuclear reactor containment

For assessment of safety and durability of a nuclear power plant (NPP), knowledge of the containment behaviour under various service and extreme conditions is crucial. To perform reliable analysis of such a large-scale structure, a sufficiently realistic but still feasible numerical model must be used, in which the relevant physical phenomena are reflected. Therefore, a constitutive model for concrete including effects of moisture and heat transfer, cement hydration, creep, shrinkage and optionally microcracking of concrete should be chosen. The present paper focuses on the simulation of the service life of NPP containment, aiming to determine the material and model parameters to enable reliable prediction of structural behaviour under various conditions. The purpose of the work is to provide a numerical model calibrated using existing measurements to predict the long-term behaviour reliably. Extensive in situ measurements are used to calibrate the model and to check the validity of the model hypotheses. Moreover, the material model parameters are systematically re-calibrated based on the continuous monitoring of the structure. The structural integrity test is reanalysed numerically to show the model capability of predicting behaviour of the structure under given loading and climate conditions.