Removable separation devices for nuclear fuel bundles

A fuel bundle for a nuclear reactor comprising:

• a plurality of fuel rods spaced laterally from one another in a matrix thereof enabling flow of liquid about the rods from a lower end of the fuel bundle toward an upper end thereof;
• a plurality of spacers spaced one from the other along the fuel bundle, each said spacer having openings for receiving the fuel rods and maintaining the rods spaced from one another in the matrix thereof;
• at least one of said rods being a part-length fuel rod terminating in an upper end below upper ends of surrounding fuel rods and below at least one of said plurality of spacers, said part-length rod defining with respect to said surrounding rods a vent volume overlying said part-length rod and having a connecting structure adjacent an upper end thereof;
• a support structure extending through an opening in said one spacer in registration with said part-length rod and having a connecting structure adjacent a lower end thereof, said support structure carrying a separation device disposed in the vent volume when said upper and lower connecting structures are connected to one another for flowing liquid laterally outwardly onto surfaces and into interstices of said surrounding fuel rods;
• said separation device including a swirler projecting laterally outwardly of said support structure;
• said separation device and the opening of said one spacer being sized relative to one another to enable withdrawal of said support structure and said separation device through the opening of said one spacer;
• said spacers having a plurality of ferrules arranged in a regular rectilinear matrix thereof, an opening in said one spacer aligned vertically above said part-length rod being void of a ferrule, the swirler comprising a plurality of blades disposed above said opening void of the ferrule such that blade tips project laterally to overlie substantially the entirety of said opening void of the ferrule.