Patent Number: 050323512
Section: claims

1. A method of constructing a spacer for maintaining a matrix of vertically aligned fuel rods within a fuel bundle in side-by-side upstanding spatial relation, the spacer being of the class having vertical tubular members interconnected by a grid, said method comprising the steps of: providing upper and lower grid members, said grid members each comprising strips of metal having major surfaces vertically aligned parallel to the vertical direction of said fuel rods within said fuel bundle, said grid members forming a matrix of crossed members defining interstitial areas for receiving and bracing individual fuel rods passing through said spacer;  providing a matrix of tubes, said matrix of tubes being aligned vertically with respect to said fuel rods within said fuel bundle and dispose for placement to interstitial locations between said fuel rods;  notching said tubes at said upper and lower ends for receiving said grids;  confronting said grids to said matrix of tubes at said upper and lower notches on said tubes;  fastening said grids to said tubes for forming a unitary grid structure for said spacer.  drilling said tubes after said fastening step to remove excess grid material from the interior of said tubes.  providing for each said grid member a first set of parallel aligned grid members, said grid members having major surfaces aligned parallel to said fuel rods and spaced for passage to an interstitial passage between columns of said fuel rods;  providing for each said member a second set of parallel aligned grid members, said grid members having major surfaces aligned parallel to said fuel rods and spaced for passage to an interstitial passage between rows of said fuel rods;  notching at least one set of said grid members for engagement to the remaining set of said grid members when said first and second sets of grid members are confronted; and,  confronting said first and second sets of grid members to fabricate said upper and lower grids.  providing swirl vanes, said provided swirl vanes including upper and lower members for confrontation to said provided upper and lower grids;  inserting said swirl vanes between said provided upper and lower grids; and,  fastening said swirl vanes to said grids at said upper and lower members for disposing said swirl vanes generally parallel to said fuel rods in said fuel bundles.  a matrix of tube members, said matrix of tube members being aligned vertically with respect to said fuel rods within said fuel bundle and disposed for placement at interstitial locations between said fuel rods;  said tube members defining at said upper and lower notches;  said grids placed within said notches at said tube members and fastened thereto, said tube members interiorly thereof having an absence of grid structure whereby said spacer includes upper and lower grids with an absence of grid material therebetween. 2. The process of claim 1 and including the step of: 3. The process of claim 1 and wherein the matrix of said grids is uniform. 4. The process of claim 1 and wherein the matrix of said grids is of variable pitch. 5. The process of claim 4 and wherein said provided matrix of tube members includes tube members of varying diameters. 6. The process of claim 1 and wherein said step of providing said upper and lower grid members comprises the steps of: 7. The process of claim 1 and including the step of: 8. A spacer for maintaining a matrix of fuel rods within a fuel bundle in side-by-side upstanding spatial relation, this spacer comprising: upper and lower grid members, said grid members each comprising strips of metal having major surfaces vertically aligned parallel to the vertical direction of said matrix of fuel rods within said fuel bundle, said upper and lower grid members forming a matrix of crossed members defining interstitial areas for receiving and bracing individual fuel rods passing through said spacer; 9. The invention of claim 8 and wherein the matrix of said grids is uniform. 10. The apparatus of claim 8 and wherein the matrix of said grids is of variable pitch. 11. The construction of claim 8 and including swirl vane members connecting said upper and lower grids.