Patent ID: 7787584

Claim:
A nuclear fuel assembly comprising: a plurality of fuel rods, each of the plurality of fuel rods having a bottom end cap which has an uplift prevention groove formed on an outer circumference of the bottom end cap; and a bottom spacer grid which filters debris and prevents the plurality of fuel rods from being uplifted, wherein the bottom spacer gird comprises: strips dividing an inner space of the bottom spacer grid into a plurality of unit grid cells, a plurality of springs protruding from the strips to hold the plurality of fuel rods, and a debris filtering member bent and protruding at a lower portion of the bottom spacer grid, wherein each of the plurality of springs comprises: a plane portion formed with a predetermined size and contacting to the outer circumference of the bottom end cap, the plane portion supporting the plurality of fuel rods with an elasticity, and a louver having a sectional plane protruded with a predetermined angle from the plane portion toward a lower portion of the bottom spacer grid, wherein the louver is located in the uplift prevention groove and has a height lower than a depth of the uplift prevention groove of the bottom end cap to avoid an interference with a bottom surface of the uplift prevention groove when the plane portion is contacted with the outer circumference of the bottom end cap.