Flow distribution device

A flow distribution device 100 suitable for a nuclear reactor pressure vessel (figure 7, 200) which encloses a reactor core (figure 7, 201). The flow distribution device 100 comprises a bowl-shaped flow distribution element 110 having a bowl wall 111 which extends upwardly from a base of the bowl to a rim 150 of the bowl. The rim 150 is attachable, in use, beneath a lower core support plate (figure 7, 204) such that the bowl occupies a portion of a plenum (206) with the bowl wall 111 being spaced from a bottom of the pressure vessel (figure 7, 208). The bowl wall 111 contains plural flow openings 112, 113 through which the reactor coolant flows into the bowl. A vortex suppression element 120 is located within the bowl, the element 120 being configured to suppress vortices in the flow of reactor coolant entering the bowl through the flow openings 112, 113, before the flow passes upwardly through the apertures in the lower core support plate (figure 7, 204).