A NUCLEAR FUEL ASSEMBLY GRID WITH DIAGONAL FUEL RETAINING SPRINGS

摘要

A support grid for laterally maintaining the relative position of elongated fuel elements within a fuel assembly for use within a core of a nuclear reactor. The grid is formed in the shape of a lattice with the intersecting lattice members defining a plurality of cells, most of which respectively support the nuclear fuel elements. The remaining cells support nuclear control rod guide tubes and instrumentation thimbles. The cells supporting the nuclear fuel elements are provided with diagonally positioned springs on two adjacent walls. The springs support the fuel elements against dimples which protrude from the opposite cell walls. The adjacent, diagonal springs in each fuel elements cell are inclined in opposite directions. The springs are formed from narrow, parallel slits in the cell wall that terminate along a line parallel to the line of intersection with the adjacent wall. The spring slits continue along that parallel line in a direction away from the spring to increase its flexure. The lattice is formed in an "egg-crate" pattern with the orthogonal members fitting over opposing vertical slits in the adjoining straps. The vertical slits are extended more than half way over the width of the straps to further increase the flexure of the retaining springs.