In-service inspection of pressurized water reactors

French legislation, which is more demanding than in other countries, had led Electricite de France, the State-owned utility, to acquire better performance in-service inspection facilities than those which existed previously. This fact has spurred the industrial development of the new technical facilities which are used worldwide today. This article presents the ''in-service inspection machine'' (MIS) for the inspection of the welds of a PWR vessel, and the inspection device of steam generator tubes; the MIS allow a remote-viewing, ultrasonic and gamma-graphic inspection; Foucault currents are the only one method adapted to the inspection steam generator tubes