Spacer grid for nuclear fuel assembly for reducing high frequency vibration

摘要

Disclosed herein is a spacer grid for a nuclear fuel assembly which is formed from grid strips of an improved structure, thus reducing flow-induced high-frequency vibration. The spacer grid has dimples or grid springs for supporting fuel rods and is formed from a plurality of grid strips assembled in a lattice shape to form lattice cells. Each of the grid strips has at least one slot formed in a planar portion of the grid strip separately from the dimple or grid spring. Therefore, characteristics of the vibration of the spacer grid can be set in a variety of different manners so that flow-induced high-frequency vibration can be reduced.

主权项

1. A spacer grid for a nuclear fuel assembly, the spacer grid comprising:
a plurality of grid strips assembled in a lattice pattern; and a 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, includes
a 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.