Back to results
US 5,278,883 AGranted
Low pressure drop spacer for nuclear fuel assemblies
AssigneeSiemens Power Corporation
InventorsJohn F. Patterson, Trond A. Bjornard
Life of this patent
Estimating the term…
Abstract
A low pressure drop spacer for positioning and retaining the fuel rods of a nuclear fuel assembly in which a plurality of upper and lower spring forks which extend through apertures in the side wall of the spacer into the assembly and through apertures in grid members which divide the assembly. The intersection and superposition of the spring forks, side wall and grid members form fuel rod passageways through which the fuel rods extend.
Claims48
A low pressure drop spacer for positioning and retaining the fuel rods of a nuclear fuel assembly, said fuel assembly being formed of a plurality of parallel elongated fuel rods, comprising:
- a perimeter strip which circumscribes a region within the assembly through which the fuel rods extend, the strip having an upstream edge and a downstream edge, the strip being adapted to form a plurality of first apertures positioned toward the upstream edge and a plurality of second apertures positioned toward the downstream edge;
- a plurality of grid members extending within the region and arranged within the region to divide the region into a plurality of subregions, the grid members being secured to the perimeter strips;
- each one of the plurality of grid members having a grid upstream edge and a grid downstream edge, the grid members being adapted to form a plurality of first apertures positioned toward the upstream edge of the perimeter strip and a plurality of second apertures positioned toward the downstream edge of the perimeter strip;
- a first spring fork comprising a first end strip and a plurality of parallel pairs of first spring strips secured to the first end strip, each one of the parallel pairs of first spring strips extending into the region and through a corresponding one of the plurality of first apertures in the perimeter strip and further extending through a corresponding one of the plurality of the first apertures in the grid members, the first fork positioned in a first plane extending in a first direction defined by the plurality of pairs of first spring strips;
- a second spring fork comprising a second end strip and a plurality of parallel pairs of second spring strips secured to the second end strip, each one of the parallel pairs of second spring strips extending into the region and through a corresponding one of the plurality of second apertures in the perimeter strip and further extending through a corresponding one of the plurality of the second apertures in the grid members, the second fork positioned in a second plane substantially parallel to said first plane, said second plane extending in a second direction defined by said plurality of pairs of second spring strips such that the second spring fork is superposed on the first spring fork so as to form fuel rod passageways through which the fuel rods extend.
2 more elements
A nuclear fuel assembly for boiling water reactors, the assembly having a plurality of elongated fuel rods supported between a lower tie plate positioned toward the bottom of the assembly and an upper tie plate positioned toward the top of the assembly;
- an outer channel surrounding the plurality of fuel rods for conducting coolant/moderator about the fuel rods from the bottom of the assembly toward the top of assembly;
- an inner channel having at least one wall for conducting coolant/moderator through the inner channel from the bottom of the assembly toward the top of the assembly;
- and
- at least one low pressure drop spacer for positioning and retaining the fuel rods, the spacer comprising:
- a perimeter strip which circumscribes a region within the assembly through which the fuel rods extend, the strip having an upstream edge and a downstream edge, the strip being adapted to form a plurality of first apertures positioned toward the upstream edge and a plurality of second apertures positioned toward the downstream edge;
- a plurality of grid members extending within the region and arranged within the region to divide the region into a plurality of subregions, the grid members being secured to the perimeter strips;
- each one of the plurality of grid members having a grid upstream edge and a grid downstream edge, the grid members being adapted to form a plurality of first apertures positioned toward the upstream edge of the perimeter strip and a plurality of second apertures positioned toward the downstream edge of the perimeter strip;
- a first spring fork comprising a first end strip and a plurality of parallel pairs of first spring strips secured to the first end strip, each one of the parallel pairs of first spring strips extending into the region and through a corresponding one of the plurality of first apertures in the perimeter strip and further extending through a corresponding one of the plurality of the first apertures in the grid members, the first fork positioned in a first plane extending in a first direction defined by the plurality of pairs of first spring strips;
- a second spring fork comprising a second end strip and a plurality of parallel pairs of second spring strips secured to the second end strip, each one of the parallel pairs of second spring strips extending into the region and through a corresponding one of the plurality of second apertures in the perimeter strip and further extending through a corresponding one of the plurality of the second apertures in the grid members, the second fork positioned in a second plane substantially parallel to said first plane, said second plane extending in a second direction defined by said plurality of pairs of second spring strips such that the second spring fork is superposed on the first spring fork so as to form fuel rod passageways through which the fuel rods extend.
6 more elements
Dependencies are inferred from the claim text.