Spacer grid assembly and locking mechanism
AssigneeThe United States of America as represented by the United States Department of Energy
InventorsHarold J. Snyder, Jr., Anthony R. Veca, Harry A. Donck
Life of this patent
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Abstract
A spacer grid assembly is disclosed for retaining a plurality of fuel rods in substantially parallel spaced relation, the spacer grids being formed with rhombic openings defining contact means for engaging from one to four fuel rods arranged in each opening, the spacer grids being of symmetric configuration with their rhombic openings being asymmetrically offset to permit inversion and relative rotation of the similar spacer grids for improved support of the fuel rods. An improved locking mechanism includes tie bars having chordal surfaces to facilitate their installation in slotted circular openings of the spacer grids, the tie rods being rotatable into locking engagement with the slotted openings.
Claims22
A spacer grid assemby for retaining a plurality of fuel rods in substantially parallel spaced relation, comprising a plurality of spacer grids spaced-apart along the length of the fuel rods, each spacer grid defining a multiplicity of rhombic openings for receiving from one to four fuel rods, each opening having at least one acute angle and at least one obtuse angle, each opening including a pair of contact means for respectively engaging each fuel rod arranged in said opening, a pair of said contact means being located at each of said acute and obtuse angles, each pair of contact means being arranged for engagement with the respective fuel rods in approximately ninety degree spaced-apart relation, the rhombic openings of adjacent spacer grids being relatively offset with their contact points being arranged for engagement with each fuel rod in opposed relation, means for maintaining the spacer grids in spaced-apart relation, and means for preventing relative rotation of the spacer grids.
A tie rod locking mechanism in a spacer grid assembly for retaining a plurality of fuel rods in substantially parallel spaced relation, spacer grids being spaced apart along the length of the fuel rods and including means for positioning the respective fuel rods, comprising sets of circular openings formed by the spacer grids in aligned relation with each other, each circular opening having an access slot which is narrower than the diameter of the circular opening, a tie rod extending through each respective set of openings, the slots facilitating insertion of the tie rods through the spacer grids, each tie rod being formed with at least one chordal flat permitting the tie rod to pass through each slot and then be rotated to insure its capture within the circular openings, and means for fixing the angular position of the tie rods.
A spacer grid for use in retaining a plurality of fuel rods in substantially parallel relation, comprising a grid structure defining a multiplicity of rhombic openings for receiving from one to four fuel rods, each of said rhombic openings having at least an acute angle and at least one obtuse angle, each opening including a pair of contact means for respectively engaging each fuel rod arranged in said opening, a pair of said contact means being located at each of said acute and obtuse angles, each pair of contact means being arranged for engagement with the respective fuel rod in approximately ninety degree spaced-apart relation, the grid structure having a symmetric boundary configuration with the multiplicity of rhombic openings being asymmetrically offset whereby, upon inversion of one spacer grid relative to another, their rhombic openings are arranged in quadrisecting and overlapping relation with their contact means being arranged for engagement with each fuel rod in opposed relation.
Dependencies are inferred from the claim text.