Abstract: The device comprises at least one assembly insertable in the enclosure through a hole situated in the vicinity of the tubular plate. Said assembly comprises a suction pipe having a curved part insertable in the casing through the hole and of a shape such that it terminates in the immediate vicinity of the plate, between the enclosure and the stack of tubes and a conduit placed inside the pipe, for connection to a cleaning liquid supply, ending in a nozzle for projecting water in a transverse direction to the pipe, along a grazing path with respect to the tubular plate and in the circumferential direction of the enclosure.

Abstract: Reactor building structure comprising a ring building roof embedded in the cylindrical skirt of the confinement enclosure.The structure is constituted by a confinement enclosure comprising a cylindrical skirt and a dome, as well as by a ring building surrounding the confinement enclosure. The ring building comprises a cylindrical skirt and a roof, the confinement enclosure and the ring building being erected on a common general foundation raft or floor. The internal structures are positioned with the confinement enclosure. The roof of the ring building is toroidal or frustum-shaped, being embedded in the cylindrical skirt of the confinement enclosure. The internal structures are disengaged from the confinement enclosure.