Etude du Confinement des Ouvrages en Béton Armé – ECOBA

The double-wall containment buildings of Pressurized Water Reactor of Nuclear Power Plant consist of a 0,65 m thickness external wall of reinforced concrete and an internal wall with 0,90-1,2 m out of biaxial prestressed concrete. The tightness of the building constitutes a safety requirement of first order. This prestressed reinforced concrete structure ensuring the confinement is susceptible to crack during its construction or in service loading. This cracking is likely to reduce the tightness of the containment building and to increase the risk of leakage in the event of severe accident. The quantification of this risk was the subject of several modelling whose parameters were obtained starting from tests on a material scale. As it is complicate to carry out experimentation on the full scale, the recourse to the computation is thus necessary. The difficulty of this exercise is related to the constitutive models used which must be able to simulate, at the same time, the mechanical behaviour of the structure (macroscopic scale) and the geometry of the cracks created (mesoscopic scale). The original idea of this project is to develop a reliable tool able to evaluate the leakage through a reinforced and prestressed concrete wall under severe loading conditions in pressure with a possible thermal loading. The validation of this tool will be carried out by the mock-up with the experimental study most possibly complete on a representative element of structure. The aim is to bring reliable data allowing to validate the models and methods established in the computation softwares used. This project is carried out within the collaboration framework between the Institute of Radioprotection and Nuclear Safety (IRSN) and three laboratories having complementary competences to conclude the project: GeM, LaSAGeC ² and LMT.