Patent Number: 
Section: claims

1. A spacer grid for a nuclear fuel assembly, the spacer grid comprising:a plurality of grid strips assembled in a lattice pattern; anda plurality of grid cells formed by the plurality of grid strips,wherein a section of each of the grid strips, corresponding to each grid cell of the plurality of grid cells, includesa dimple supporting a fuel rod and having slits formed in a lateral direction perpendicular to the fuel rod and arc-shape portions protruding inwards or outwards between the slits, andat least one set of slots formed entirely in a planar surface of the section separately from the slits surrounding the dimple and having at least one of a wave shape, a saw tooth shape and a slanted line shape extending in the lateral direction along the slits of the dimple, said at least one set of slots including a first slot disposed in an upper position of the section above and apart from the dimple and a second slot disposed in a lower position of the section below and apart from the dimple,wherein said at least one set of slots is provided for reducing flow-induced high-frequency vibration of the spacer grid. 2. The spacer grid as set forth in claim 1, wherein the first slot and the second slot have the same shape each other. 3. The spacer grid as set forth in claim 1, wherein the first slot and the second slot have different shapes each other. 4. The spacer grid as set forth in claim 1, wherein the first slot and the second slot are vertically symmetric with respect to an imaginary center line of the section. 5. The spacer grid as set forth in claim 1, wherein the at least one set of slots further includes a third slot disposed in the upper position of the section apart from the dimple and a fourth slot disposed in the lower position of the section apart from the dimple. 6. The spacer grid as set forth in claim 5, wherein the third slot and the fourth slot have the same shape each other. 7. The spacer grid as set forth in claim 5, wherein the third slot and the fourth slot have different shapes each other. 8. The spacer grid as set forth in claim 5, wherein the third slot and the fourth slot are vertically symmetric with respect to an imaginary center line of the section.