Confinement. Containments

The steam generators are installed inside the reactor building. In case of accident with the primary circuit, radioactive compounds can be released and must be confined in order to limit the radioactive releases in the atmosphere. This confinement function is ensured by the reactor building walls, called containment building. Different associated systems allow to limit the radioactive releases outside the building by reducing the indoor pressure to a value close to the atmospheric pressure in few hours or days (containment spray system and core safety injection system). This paper describes first the general conceiving rules of reactors confinement and the different type of containments. Then the possible internal and external aggressions of the containment are reviewed with the safety codes and standards. The next parts concern the dimensioning and calculations (prestress dimensioning and numerical modeling), the problems related to the realization (organization of works and main problems encountered), the testing and in-service inspection of the containment (mechanical resistance and tightness), the over-dimensioning accidental considerations (existing containments and future projects). (J.S.)