Patent Number: 
Section: claims

1. A grid strap for a spacer grid, comprising:an upper plate (11a) having a dimple (12a) protruding in one direction from one side of the upper plate (11a) and an upper base (15a) extending downwardly from a center of the upper plate (11a);a pair of symmetrically opposed upper left-hand and upper right-hand supports (16a and 16b) branching off downwardly from the upper base (15a);a lower plate (11b) having a dimple (12b) protruding in the one direction and a lower base (15b) extending upwardly from a center of the lower plate (11b);a pair of symmetrically opposed lower left-hand and lower right-hand supports (16a and 16b) branching off upwardly from the lower base (15b);a pair of symmetrically opposed bridges (18a and 18b) connected to the pair of symmetrically opposed upper left-hand and upper right-hand supports (16a and 16b) on one end of each bridge (18a and 18b) and the pair of symmetrically opposed lower left-hand and lower right-hand supports (16a and 16b) on an opposing end of each bridge (18a and 18b); anda conformal curvature (17) extending from one bridge (18a) through a center region to the other bridge (18b), the conformal curvature (17) having top and bottom edges (21a and 21b) defining a distance therebetween,wherein the center region is the midpoint between the bridges (18a and 18b) and the distance between the top and bottom edges (21a and 21b) being lesser at the midpoint than at the bridges (18a and 18b),wherein the conformal curvature (17) is curved to be concave in the direction opposite to the one direction in which the dimples (12a and 12b) protrude,wherein the upper and lower bases (15a and 15b), upper left-hand and right-hand supports (16a and 16b), lower left-hand and right-hand supports (16a and 16b), bridges (18a and 18b) and conformal curvature (17) combine to form a spacer grid spring (14) protruding in the direction opposite to the one direction in which the dimples (12a and 12b) protrude,wherein all the area of the conformal curvature (17) including top and bottom edges (21a and 21b) are configured to contact a fuel rod (3),wherein the bridges (18a and 18b) are curved to be concave in the direction opposite to the one direction in which the dimples (12a and 12b) protrude,wherein each bridge (18a and 18b) is curved around a lateral axis of the grid strap and configured to be spaced from and parallel to a longitudinal axis of a fuel rod (3), andwherein the top and bottom edges (21a and 21b) are curved to be tapered toward the center region. 2. The grid strap of claim 1, wherein each of the pair of symmetrically opposed upper left-hand and right-hand supports and each of the pair of symmetrically opposed lower lefthand and right-hand supports comprise a wedge-shape. 3. The grid strap of claim 1, wherein the rigidity of the left-hand supports and right-hand supports (16a and 16b) is lower than the rigidity of the conformal curvature (17).