Abstract: The secondary water supply for a steam generator is provided by a toroidal or semitoroidal collector (38) placed in the bottom of the annular recirculation space (32) of the generator, in a larger diameter part (36) of the outer envelope. The collector (38) has holes (40) ensuring a vertical mean flow of the secondary water into the annular space (32). The cross-section of the holes is chosen in such a way as to trap in the collector the migrating bodies or members from the secondary water circuit and which could damage the steam generator tubes. At least one access orifice makes it possible to extract these migrating bodies from the collector during maintenance operations.

Abstract: In a steam generator equipping a nuclear power station and having inverted U-Lubes connected to a tube plate or sheet (12) and surrounded by an inner envelope (26) having a lower flow distribution plate (41) in its bottom part, the space (46) known as a waterway between the tube plate (12), the flow distribution plate (41) and the hot and cold branches of the tubes contains a deflection and purging box (44). The latter extends over the entire length of the waterway and in height up to the upper edge of the lower envelope (26). It is provided on its lower face with purging orifices (50) and fulfils both a deflection function and a secondary fluid drainage function in the vicinity of the tube plate (12).