Abstract: The flow distribution baffle (14) is placed inside the bundle wrapper (7) of the steam generator, at its lower part,-near the steam generator tube plate. Passing through the flow distribution baffle (14) are openings (17, 18) for the passage of tubes of the steam generator bundle and feedwater. The flow distribution baffle (14) comprises a central zone (15) of more or less circular shape with, as its axis, the axis of the steam generator and a radius (R1) smaller than 40% of the internal radius (R) of the bundle wrapper (7), and a more or less annular peripheral zone between the central zone and the outer edge of the flow distribution baffle (14). In the central zone (15) the openings (17) for the passage of tubes and feedwater in the flow distribution baffle have a cross section (S1), the cross-sectional area of which is greater than the cross-sectional area of the cross section (S2) of the openings (8) for the passage of tubes and feedwater in the peripheral zone.

Abstract: The device comprises a threaded rod (11a) capable of being screwed into the threaded bore (10') traversing the core (10) and solid, at one of its ends, with a blocking element (11b) the external diameter of which is greater that the diameter of the rod (11a) and which comes into engagement in that end (7) of the casing (4) of the plug (3) opposite the closure base (5) of the plug when the threaded rod (11a) is screwed into the core (10). The blocking element (11b) cooperates with the end of the casing (4) of the plug to achieve the blocking, against rotation and/or translation, of the obturating device (11). The threaded rod (11a) may comprise a transverse orifice in which a braking part is engaged.

Abstract: The device comprises a sleeve (1) and a stopper (5). The inside bore of the sleeve (1) comprises a part having a diameter smaller than the outside diameter of the stopper (5) and ending in a shoulder (2c), against which the stopper (5) comes to bear. Swaging (9) enables the stopper (5) to be fixed in the sleeve (1). The fastening is completed by three sealing welds (10a, 10b, 10c), between which are provided an aperture (4) passing through the side wall of the sleeve (1) and an aperture (8) passing through the side wall of the stopper (5). The device is used in particular for closing holes in a tubular plate of a steam generator of a pressurized water nuclear reactor.