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Fuel assembly

A fuel assembly and fuel technology, which is applied in the directions of reactor fuel elements, nuclear power generation, climate sustainability, etc., can solve problems such as spring-loaded structures that are not yet known

Inactive Publication Date: 2004-04-28
HITACHI LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0022] However, no spring-loaded structure for mounting two or more free ring springs in a lattice position is known to date

Method used

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  • Fuel assembly
  • Fuel assembly
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Examples

Experimental program
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Effect test

no. 1 example

[0117] now compare Figures 1 to 6 A first embodiment of the present invention is described. A vertical sectional view showing the structure of the fuel assembly of this embodiment is shown at figure 2 in, along figure 2 The cross-sectional view of the A-A line in the middle is shown in image 3 middle.

[0118] now compare figure 2 and 3 , the fuel assembly 1 includes 74 fuel rods 2 filled with fuel pellets (not shown), they are located in a square lattice of 9 rows × 9 columns; two water rods 3, which can be arranged in 7 fuel rods In the region of 2; the fuel positioning member 4, which is used to fix the fuel rod 2 and the water rod 3, so that the mutual radial distance remains unchanged; an upper tie plate 5 and a lower tie plate 6, which are used to fix respectively An upper end portion and a lower end portion of a fuel bundle composed of fuel rods 2; and a fuel tank 8 for covering the outer peripheral portion of the above structure.

[0119] The fuel rods 2 inclu...

no. 2 example

[0147] Now compare Figures 7 to 8 A second embodiment of the present invention is described. The present embodiment is characterized in that the spring arrangement and the shape of the support are changed in the fuel retainer located above the upper end of the first short-length fuel rod 2b1.

[0148] Figure 7 The top view of the figure shows the structure of the fuel spacer 204b in this embodiment. In the fuel positioning member 204b, compared with the first embodiment figure 1 The parts common to the parts in the shown fuel positioning member 4b use the same reference numerals and will not be repeated here.

[0149] Figure 7 Fuel locator 204b is shown with figure 1 The fuel spacer 4b shown differs in that the cell 9 at the second grid position 7b associated with the fuel rod 2b2 of the second shorter length is omitted, and the support at the second grid position 7b is instead Item 218. The support 218 connects the two cells 9C and 9D outside and adjacent to the s...

no. 3 example

[0160] now compare Figures 9 to 11 A third embodiment of the present invention is described. This embodiment is characterized in that the shape and supporting structure of the supporting member are further changed in the fuel positioning member located above the upper end of the first short-length fuel rod 2b1. Figure 9 The top view of shows the structure of the fuel spacer 304b in this embodiment. In the fuel locator 304b, compared with figure 1 The same reference numerals are used for the same parts in the fuel positioning member 4b of the first embodiment described, and will not be repeated here.

[0161] Figure 9 Fuel locator 304b is shown with figure 1 The fuel locator 4b shown differs in that it is located in a first lattice position relative to a first short length fuel rod 2b1 (see image 3 ) support 17 is replaced by support 317. The support 317 connects the two cells 9A and 9B and the cell 9E to each other, and the cells 9A and 9B are on both sides of the ...

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PUM

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Abstract

A fuel assembly having a plurality of fuel rods arranged in a square lattice array. The fuel rods include a plurality of short-length fuel rods each having a fuel active length shorter than that of each of remaining ones of the fuel rods. At least one water rod is arranged in a region in which one or more of the fuel rods are arrangeable in the array, and a plurality of fuel spacers are provided at a plurality of positions in the axial direction for holding the plurality of fuel rods and the at least one water rod, with mutual radial intervals therebetween being kept immovable. The plurality of short-length fuel rods include at least one first short-length fuel rod arranged in the outermost peripheral region of the square lattice array. Each of the plurality of fuel spacers include a plurality of cylindrical members.

Description

technical field [0001] The present invention relates to fuel assemblies for use in boiling water reactors, and more particularly, to fuel assemblies including fuel spacers. Background technique [0002] For example, a fuel assembly for a boiling water reactor has been disclosed in Japanese Patent Laid-Open No. Hei 2-163695. This fuel assembly includes multiple fuel rods and two water rods. The fuel rods are located in a short grid of 9 rows by 10 columns. These fuel rods and water rods constituting the fuel bundle are kept immovable at mutually specific intervals by a plurality of fuel positioners arranged in the axial direction. [0003] The fuel locator includes a plurality of cylindrical members; a belt member; a plurality of annular springs; water rod holders each forming a generally omega-shaped cross-section for retaining the water rods. A number of cylindrical pieces are joined to each other to form a bundle. Each of the cylindrical members is arranged in a grid p...

Claims

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Application Information

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IPC IPC(8): G21C3/326G21C3/328G21C3/332G21C3/344G21C3/356
CPCG21Y2004/30G21C3/344G21Y2002/304Y02E30/38G21C3/328G21C3/356Y02E30/40G21Y2002/201G21C3/326Y02E30/31Y02E30/30
Inventor 平野敦也菅野智入部真黑崎英树相泽泰博福本隆
Owner HITACHI LTD