CN111477360A

CN111477360A - Annular fuel assembly location grillwork

Info

Publication number: CN111477360A
Application number: CN202010448655.0A
Authority: CN
Inventors: 史宝磊; 何晓军; 季松涛; 邹远方; 韩智杰; 李思远; 刁均辉
Original assignee: China Institute of Atomic of Energy
Current assignee: China Institute of Atomic of Energy
Priority date: 2020-05-25
Filing date: 2020-05-25
Publication date: 2020-07-31

Abstract

The invention belongs to the technical field of fuel assemblies, and particularly relates to an annular fuel assembly positioning grid. Comprises a supporting piece, an outer strip and an inner strip; a plurality of inner strips are mutually inserted and arranged to form a square or hexagonal grid structure, and a circle of outer strips are welded and fixed on the periphery of the square or hexagonal grid structure; the support members are disposed where the inner straps cross each other. The supporting piece is octagonal. The octagonal supporting piece is processed into a rigid convex or a spring to serve as a supporting structure, is used for supporting the fuel rods at the opposite corners of the grids and is suitable for fuel assemblies with large rod diameters and small grid distances of the fuel rods; the clamping force of the octagonal support on the fuel rod can be adjusted according to the design requirement of the fuel assembly by adjusting the rigid bulge or the spring of the octagonal support; the rigid convex or the spring arranged on the octagonal support can be adjusted, so that the fuel assembly can be suitable for fuel rods with different rod diameters in the same fuel assembly.

Description

Annular fuel assembly location grillwork

Technical Field

The invention belongs to the technical field of fuel assemblies, and particularly relates to an annular fuel assembly positioning grid.

Background

During the operation of a nuclear power plant reactor, the performance of nuclear fuel is an important factor affecting the safety and economy of the reactor. Therefore, the research on fuel elements is put on a very prominent position internationally, and various performances of the nuclear fuel elements are continuously improved by optimizing the design of the fuel elements, adopting advanced structural materials, improving element manufacturing processes and other methods, so that nuclear power is promoted to develop towards a safer and more economic direction.

In the existing pressurized water reactor fuel assembly design, the fuel rods are generally clamped and suspended by a positioning grid. The spacer grids serve as support clamps for the fuel elements and need to resist the gravity action of the fuel elements, the clamping force of the springs clamping the fuel rods is drastically reduced due to the irradiation, the fuel rods generally fall on the bottom nozzle, and the fuel rods may move up and down under the flowing action of the coolant, which may cause the risk of breakage of the fuel rods.

If parameters of fuel elements are optimized and the universal fuel assembly appearance structure design is adopted, the novel assembly can be suitable for the current mature reactor core. If the novel annular fuel element is adopted, the outer diameter is large, the weight is increased, the clamping force of the required spacer grid can be increased by about 2-4 times, the space for placing clamping pieces such as springs and rigid protrusions is small, the probability that the fuel element falls on the lower pipe seat during operation is increased, and the probability that the fuel element moves up and down in the process of restarting after stopping and changing fuel is also increased.

Meanwhile, in the design and manufacture of the existing fuel assembly spacer grids, the spacer grids are basically composed of inner and outer strips. Due to the complexity of their strips, more than 30 molds are required for manufacturing. After the molds are determined, if the characteristics of the spacer grid, such as flow resistance, the distribution of the coolant among the fuel assemblies, etc., are to be changed, it is necessary to change the shape of almost all of the molds therein, which greatly increases the workload.

Accordingly, there is a need to design a new type of spacer grid for fuel assemblies that overcomes the deficiencies of the prior art.

Disclosure of Invention

It is an object of the present invention to provide an annular fuel assembly spacer grid which overcomes the above-mentioned deficiencies of the prior art.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

an annular fuel assembly spacer grid comprising a support, an outer strip, an inner strip; a plurality of inner strips are mutually inserted and arranged to form a square or hexagonal grid structure, and a circle of outer strips are welded and fixed on the periphery of the square or hexagonal grid structure; the support members are disposed where the inner straps cross each other.

The supporting piece is octagonal.

The supporting piece is of an integral structure or formed by splicing two parts or four parts.

When the supporting piece is formed by splicing two parts or four parts, the hanging hook is arranged on the supporting piece.

Four sides in the support member octagon are opened and are had slot E and interior strip grafting, and other four sides are located the grid that interior strip was pegged graft each other and are formed, and four sides that lie in the grid that interior strip was pegged graft each other and are provided with just protruding or spring.

When the grid formed by mutually inserting the inner strips is used as a guide pipe channel, rigid bulges or springs are not arranged on the supporting piece.

The inner strip is divided into a horizontal structure and a vertical structure.

The inner strip which is horizontally arranged is provided with a slot A and a slot B, the slot A is downwards opened from the upper end of the inner strip which is horizontally arranged, the slot B is upwards opened from the lower end of the inner strip which is horizontally arranged, and the slot A corresponds to a slot E on the octagonal supporting piece; the slot B corresponds to a slot D on the vertically arranged inner strip; the inner strip which is vertically arranged is provided with a slot C and a slot D, the slot C and the slot D are downwards opened from the upper end of the inner strip which is vertically arranged, and the slot C corresponds to the slot E on the octagonal supporting piece; slot D corresponds to slot B on the horizontally disposed inner strip.

Springs are provided on the outer strips and the inner strips constituting the outermost grid.

The location grid is applied to a pressurized water reactor, a marine power reactor, a fast reactor, a boiling water reactor, a power reactor and a heavy water reactor.

The beneficial effects obtained by the invention are as follows:

1. compared with the existing pressurized water reactor fuel assembly positioning grid, the octagonal supporting piece is processed into rigid protrusions or springs to serve as a supporting structure, is used for supporting fuel rods at the opposite corners of the grid, and is suitable for fuel assemblies with large fuel rod diameters and small grid distances;

2. the clamping force of the octagonal support on the fuel rod can be adjusted according to the design requirement of the fuel assembly by adjusting the rigid bulge or the spring of the octagonal support;

3. compared with the existing strip-shaped positioning grillwork, the octagonal supporting piece can be formed by punching and welding sheets with certain sizes, has simple structural form, is convenient to manufacture, needs a small number of moulds, is simple to assemble, has high finished product rate and is convenient to disassemble; and because the rigid bulge or the spring arranged on the octagonal supporting piece can be adjusted, the fuel rod assembly can be suitable for fuel rods with different rod diameters in the same fuel assembly.

Drawings

FIG. 1 is a schematic diagram of a ring fuel assembly spacer grid structure;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a block diagram of an embodiment of a support;

FIG. 4 is a diagram of a second embodiment of the support member;

FIG. 5 is a diagram of an embodiment of a support member;

FIG. 6 is a view of the inner belt structure in a horizontal arrangement;

FIG. 7 is a view of the inner band in a vertical arrangement;

in the figure: 1. a support member; 2. an outer band; 3. an inner band; 4. a guide tube channel; 5. a slot A; 6. a slot B; 7. a slot C; 8. a slot D; 9. a spring; 10. rigid and convex; 11. a slot E; 12. and (4) hanging hooks.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments.

As shown in fig. 1-2, the annular fuel assembly spacer grid of the present invention comprises a support member 1, an outer strip 2, an inner strip 3, a guide tube passage 4; a plurality of inner strips 3 are mutually spliced and arranged to form a square or hexagonal grid structure, and a circle of outer strips 2 are welded and fixed on the periphery of the square or hexagonal grid structure; the support 1 is arranged where the inner strips 3 cross each other.

As shown in fig. 3-5, the support member 1 is octagonal and includes a plurality of structural forms: the structure can be an integral structure, or formed by splicing two parts, or formed by splicing four parts; when the support 1 is formed by splicing two or four parts, the hooks 12 are provided thereon for assembly. Four sides of the octagon are provided with slots E11 for being inserted with the inner strips 3, the other four sides are positioned in grids formed by the mutual insertion of the inner strips 3, and four sides positioned in the grids formed by the mutual insertion of the inner strips 3 are provided with rigid protrusions 10 or springs 9 for supporting fuel rods. When the grid of the inner strips 3 is inserted into one another as the guide tube channel 4, no rigid projections 10 or springs 9 are provided on the support 1.

As shown in fig. 6 to 7, the inner strip 3 is divided into a horizontal and a vertical structure:

the inner strap 3 which is horizontally arranged is provided with a slot A5 and a slot B6, the slot A5 is downwards opened from the upper end of the inner strap 3 which is horizontally arranged, the slot B6 is upwards opened from the lower end of the inner strap 3 which is horizontally arranged, and the slot A5 corresponds to the slot E11 on the octagonal support 1; slot B6 corresponds to slot D8 on the vertically disposed inner strip 3.

The vertically arranged inner strap 3 is provided with a slot C7 and a slot D8, the slot C7 and the slot D8 are downward opened from the upper end of the vertically arranged inner strap 3, and the slot C7 corresponds to the slot E11 on the octagonal support 1; slot D8 corresponds to slot B6 on the horizontally disposed inner strip 3.

Springs 9 are provided on the outer strip 2 and the inner strip 3 constituting the outermost grid to form a multi-point support for the fuel rods at the opposite side and corner grids.

The invention can be applied to pressurized water reactors, marine power reactors, fast reactors, boiling water reactors, power reactors and heavy water reactors.

Claims

1. An annular fuel assembly spacer grid, comprising: comprises a supporting piece, an outer strip and an inner strip; a plurality of inner strips are mutually inserted and arranged to form a square or hexagonal grid structure, and a circle of outer strips are welded and fixed on the periphery of the square or hexagonal grid structure; the support members are disposed where the inner straps cross each other.

2. The annular fuel assembly spacer grid of claim 1, wherein: the supporting piece is octagonal.

3. The annular fuel assembly spacer grid of claim 2, wherein: the supporting piece is of an integral structure or formed by splicing two parts or four parts.

4. The annular fuel assembly spacer grid of claim 3, wherein: when the supporting piece is formed by splicing two parts or four parts, the hanging hook is arranged on the supporting piece.

5. The annular fuel assembly spacer grid of claim 2, wherein: four sides in the support member octagon are opened and are had slot E and interior strip grafting, and other four sides are located the grid that interior strip was pegged graft each other and are formed, and four sides that lie in the grid that interior strip was pegged graft each other and are provided with just protruding or spring.

6. The annular fuel assembly spacer grid of claim 5, wherein: when the grid formed by mutually inserting the inner strips is used as a guide pipe channel, rigid bulges or springs are not arranged on the supporting piece.

7. The annular fuel assembly spacer grid of claim 5, wherein: the inner strip is divided into a horizontal structure and a vertical structure.

8. The annular fuel assembly spacer grid of claim 7, wherein: the inner strip which is horizontally arranged is provided with a slot A and a slot B, the slot A is downwards opened from the upper end of the inner strip which is horizontally arranged, the slot B is upwards opened from the lower end of the inner strip which is horizontally arranged, and the slot A corresponds to a slot E on the octagonal supporting piece; the slot B corresponds to a slot D on the vertically arranged inner strip; the inner strip which is vertically arranged is provided with a slot C and a slot D, the slot C and the slot D are downwards opened from the upper end of the inner strip which is vertically arranged, and the slot C corresponds to the slot E on the octagonal supporting piece; slot D corresponds to slot B on the horizontally disposed inner strip.

9. The annular fuel assembly spacer grid of claim 1, wherein: springs are provided on the outer strips and the inner strips constituting the outermost grid.

10. The annular fuel assembly spacer grid of claim 1, wherein: the location grid is applied to a pressurized water reactor, a marine power reactor, a fast reactor, a boiling water reactor, a power reactor and a heavy water reactor.