Patent Number: 061817635
Section: claims

1. A fuel bundle assembly for a boiling water nuclear reactor comprising a plurality of fuel rods having respective fuel columns therein, and arranged in an ordered array, extending between upper and lower supports, said plurality of fuel rods enclosed within a hollow, open-ended channel member; at least one water rod supported on the lower support and extending upwardly toward said upper support, said at least one water rod having an upward flow path including at least one inlet at a lower end of said upward flow path, and a downward flow path communicating with and extending from an upper end of said upward flowpath and including at least one outlet at a lower end of said downward flow path, said at least one outlet located in a range of 35% to 65% of the height of the fuel columns within the fuel rods, and wherein there are no outlets in said water rod other than in said downward flow path in said range. 2. The assembly of claim 1 wherein said downward flow path is enclosed within said upward flow path. 3. The assembly of claim 2 wherein said upward flow path is defined by a first tube and said downward flow path is defined by a second tube located in said first tube, said at least one outlet formed in said first tube, with said second tube connected to said outlet. 4. The assembly of claim 1 wherein said at least one inlet is located above the lower support structure. 5. The assembly of claim 1 wherein said upward flow path has a cross-sectional area greater than said downward flow path. 6. The assembly of claim 1 wherein said at least one inlet is located below the lower support structure.