Abstract: The vessel of the nuclear reactor includes at least three assemblies (22) distributed around the periphery of the core support plate (25), each comprising a key (26) fixed to the inner surface of the wall (21) of the vessel at the core support plate (25) and a cut-out (29) in the external edge of the core support plate (25) and open towards the outside in order to receive, with a clearance, an end part (30) of the key (26). The cut-out (29) includes an upper surface (29d) perpendicular to the axis of the wall (21) of the vessel and of the lower internals (23), which is machined in the core support plate (25) in order to retain the internals (23) in the event of a drop. A keyhole slot (28) is fixed inside the cut-out (29). In order to carry out the adjustment of the dimensions of the keyhole slot (28), a standard keyhole slot may be used, equipped with distance measurement sensors in order to obtain the desired clearances between the key (26) and the keyhole slot (28).

Abstract: The equipment comprises a bottom plate formed with outlet openings for the coolant, a top plate, spacer rods interconnecting the plates, and cluster guides for guiding control clusters. At least some of the guides have respective top lengths that project above the top plate and bottom lengths that extend between the plates. Each bottom length includes a base bearing against a frustoconical seat secured to the bottom plate, and it is subjected to the force of resilient means. Together, the lengths of each guide constitute a one-piece cartridge suitable for insertion in a corresponding column. The guide also includes a cap for receiving the top length, which cap is fixed to the top plate against which the resilient means bear.

Abstract: Internal equipments located above the core of a nuclear reactor have a bottom plate formed with outlet openings for the core coolant, a top plate, spacer columns interconnecting the plates, and guides for control clusters that are vertically displacable between a position in which they are in the core and a position in which they are out of the core. At least some guides each have a top length projecting above the top plate, and a bottom length extending between the plates and placed in a corresponding spacer column. Each cluster guide constitutes a cartridge insertable in a respective column, provided with a flange for fixing to the top plate and provided at its bottom end with springs for centering the guide within the column.

Abstract: A partitioning device is provided which can be used in a pressurized water nuclear reactor. It occupies the space between the prismatic shaped core of the reactor, and a cylindrical casing and comprises vertical partitioning plates surrounding the core and reinforcement elements placed between the partitioning plates and the casing. It comprises panels distributed into horizontal rows in vertical columns, all the panels of the same row being identical and having vertical partitioning plates welded together and fast with criss-crossed horizontal and vertical reinforcements bearing on the casing and with vertical tubes. The stacked tubes of a same column form a post resting on a core support plate. Solid vertical keys connect the panels in the different columns together and to the casing.