CN212135972U

CN212135972U - Co-extrusion annular fuel rod

Info

Publication number: CN212135972U
Application number: CN202020891824.3U
Authority: CN
Inventors: 何晓军; 史宝磊; 季松涛; 邹远方; 刁均辉; 徐西安
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: 2020-12-11
Anticipated expiration: 2030-05-25

Abstract

The utility model relates to a nuclear fuel technical field specifically discloses a coextrusion formula annular fuel rod, wherein the heat conduction has been strengthened to zero clearance between fuel pellet and the cladding, has reduced fuel pellet central temperature, and no longer needs traditional pressure spring structure, has increased the stability of operation, has reduced radioactive waste. The utility model discloses a fuel rod assembly manufacturing process has been simplified to the fuel rod structure, need not fill the helium to fuel rod inside in manufacturing, the cost is reduced.

Description

Co-extrusion annular fuel rod

Technical Field

The utility model belongs to the technical field of nuclear fuel, concretely relates to coextrusion formula annular fuel rod.

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.

The nuclear fuel is generally designed into a solid cylinder shape and consists of an upper end plug, a lower end plug, a pellet, a compression spring and a cladding, and a coolant flows through the cladding to cool a fuel rod.

The benefit of the annular fuel is that at high linear power densities, the temperature in the center of the fuel is still low, there is less stored energy in the fuel, and there is less fission gas release than with conventional solid cylindrical fuels. Better fuel performance can be expected under normal operating and transient conditions.

In the existing annular fuel rod, gaps exist between the outer surface of the inner cladding and the inner surface of the annular fuel pellet and between the inner surface of the outer cladding and the outer surface of the annular fuel pellet, so that the annular fuel pellet is not favorably radiated, the assembly process has high precision requirement, and the assembly and the processing are inconvenient.

In the existing sodium-cooled fast reactor fuel element, the outer surface of the fuel rod cladding tube generally adopts a wire winding positioning structure to transversely position the fuel rod in the assembly, and the coolant is enabled to generate transverse flow by the transverse acting force of the wire winding, so that the heat transmitted from the surface of the cladding tube is better transmitted to the central area of the coolant, the highest temperature of the surface of the fuel rod cladding tube is effectively reduced, and the safety of the assembly is ensured. However, since there is inevitably a gap between the wire wrap and the outer surface of the fuel rod cladding tube, vibration is easily generated between the wire wrap and the outer surface of the fuel rod cladding tube, which affects the stability of the structure, and the coolant flow area of the contact part of the wire wrap and the fuel rod is narrow and long, and there are vortex and flow stagnation areas on the back flow surface of the wire wrap to the coolant, which also brings obstruction to heat conduction.

Therefore, it is desirable to design a fuel rod that eliminates the above-mentioned drawbacks.

Disclosure of Invention

An object of the utility model is to provide a coextrusion formula annular fuel rod eliminates the clearance between fuel pellet and the cladding and optimizes the heat transfer effect of wire winding and fuel rod contact part.

The technical scheme of the utility model as follows:

a co-extrusion annular fuel rod comprises an upper end plug, a lower end plug, an inner cladding, an outer cladding and an annular fuel core;

the annular fuel core, the inner cladding and the outer cladding are processed in a co-extrusion mode, no gap exists between the annular fuel core and the inner cladding and between the annular fuel core and the outer cladding, heat conduction is enhanced, and central temperature is reduced;

and an upper end plug and a lower end plug are connected above the inner cladding and the outer cladding.

The outer surface of the outer casing is provided with N turbulence wings, wherein N is more than or equal to 1.

The turbulence wings are spirally distributed on the outer surface of the outer cladding.

The turbulence wings and the outer surface of the outer wrapping shell are integrally processed and formed, so that the heat exchange area can be obviously increased, the whole heat dissipation is facilitated, and the phenomenon that the heat transfer effect of local heat of the wrapping shell is poor due to the poor heat transfer effect of the contact part of the wire winding positioning structure and the surface of the fuel rod is eliminated.

When the number of the turbulence wings is multiple, the turbulence wings are distributed on the outer surface of the outer wrapping shell at equal angles along the axial direction.

The height of the turbulence wings is equal to the distance between two adjacent annular fuel rods in the fuel assembly, and the two adjacent annular fuel rods can be limited through the turbulence wings.

Helium does not need to be filled in the fuel rod.

The annular fuel core is a dispersion fuel.

The annular fuel core is metal fuel.

The reactor is suitable for pressurized water reactors, fast reactors, low-temperature heat supply reactors, space reactors, boiling water reactors, micro-reactors, zero-power reactors, heavy water reactors, power reactors and marine power reactor types.

The beneficial effects of the utility model reside in that:

(1) the utility model discloses no clearance between the fuel pellet of fuel rod and the cladding has strengthened the heat conduction, has reduced fuel pellet central temperature, and no longer needs traditional compression spring structure, has increased the stability of operation, has reduced radioactive waste.

(2) The utility model discloses a vortex wing structure and the outer shell integrated into one piece of fuel rod, seamless between the two compares with wire winding location structure and can show increase heat transfer area, does benefit to whole heat dissipation.

(3) The utility model discloses the vortex wing structure of fuel rod can show the reinforcing and transversely stir the effect of mixing.

(4) The utility model discloses a fuel rod assembly manufacturing process has been simplified to the fuel rod structure, need not fill the helium to fuel rod inside in manufacturing, the cost is reduced.

Drawings

FIG. 1 is a cross-sectional view of a co-extruded annular fuel rod without turbulators;

FIG. 2 is a schematic longitudinal cross-sectional view of a co-extruded annular fuel rod without turbulators;

FIG. 3 is a schematic cross-sectional view of a co-extruded annular fuel rod having turbulators;

FIG. 4 is a schematic longitudinal cross-sectional view of a co-extruded annular fuel rod having turbulators;

FIG. 5 is a schematic cross-sectional view of a co-extruded annular fuel rod with multiple flow vanes.

In the figure: 1. an upper end plug; 2. a lower end plug; 3. an inner envelope; 4. an outer envelope; 5. an annular fuel core; 6. and a spoiler.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

A co-extruded annular fuel rod as shown in fig. 1 and 2 comprises an upper end plug 1, a lower end plug 2, an inner cladding 3, an outer cladding 4 and an annular fuel core 5.

The annular fuel core body 5, the inner wrapping shell 3 and the outer wrapping shell 4 are processed in a co-extrusion mode, no gap exists between the annular fuel core body and the inner wrapping shell, heat conduction is enhanced, and the central temperature of the fuel core blocks is reduced.

An upper end plug 1 is connected above the inner cladding 3 and the outer cladding 4, and a lower end plug 2 is connected below.

The annular fuel core 5 is a dispersoid or a metal fuel.

Traditional co-extrusion processing mode produces the inhomogeneous condition of core distribution easily at co-extrusion piece's both ends, consequently this application co-extrusion formula annular fuel rod is through cutting off behind the inhomogeneous part of both ends core, and end plug 1 and lower end plug 2 are welded respectively to the rethread.

As shown in figures 3 and 4, N spoiler wings 6 are processed on the outer surface of the outer cladding 4, wherein N is more than or equal to 0. The turbulence wings 6 are spirally distributed on the outer surface of the outer cladding 4 and are integrally processed and formed with the outer surface of the outer cladding 4, so that the heat exchange area can be obviously increased, the whole heat dissipation is facilitated, and the phenomenon of poor heat transfer effect of local heat of the cladding caused by poor heat transfer effect of the contact part of the wire winding positioning structure and the surface of the fuel rod is eliminated.

As shown in fig. 5, when there are a plurality of flow-disturbing wings 6, they are distributed on the outer surface of the outer envelope 4 at equal angles along the axial direction. The height of the turbulence wings 6 is equal to the distance between two adjacent annular fuel rods in the fuel assembly, and the two adjacent annular fuel rods can be limited by the turbulence wings 6.

A co-extrusion formula annular fuel rod, be applicable to pressurized-water reactor, fast reactor, low temperature heat supply heap, space heap, boiling water heap, pile a little, zero power heap, heavy water heap, power heap, marine power heap type.

Claims

1. A co-extruded annular fuel rod characterized by: comprises an upper end plug (1), a lower end plug (2), an inner packing shell (3), an outer packing shell (4) and an annular fuel core body (5);

the annular fuel core (5), the inner cladding (3) and the outer cladding (4) are processed in a co-extrusion mode, no gap exists between the annular fuel core and the inner cladding, heat conduction is enhanced, and central temperature is reduced;

an upper end plug (1) is connected above the inner cladding (3) and the outer cladding (4), and a lower end plug (2) is connected below the inner cladding and the outer cladding.

2. A co-extruded annular fuel rod of claim 1 wherein: the outer surface of the outer casing (4) is provided with N turbulence wings (6), wherein N is more than or equal to 1.

3. A co-extruded annular fuel rod of claim 2 wherein: the turbulence wings (6) are spirally distributed on the outer surface of the outer cladding (4).

4. A co-extruded annular fuel rod of claim 3 wherein: the turbulence wings (6) and the outer surface of the outer wrapping shell (4) are integrally processed and formed, so that the heat exchange area can be obviously increased, the whole heat dissipation is facilitated, and the phenomenon of poor heat transfer effect of local heat of the cladding caused by poor heat transfer effect of the contact part of the wire winding positioning structure and the surface of the fuel rod is eliminated.

5. A co-extruded annular fuel rod of claim 4 wherein: when the number of the turbulence wings (6) is multiple, the turbulence wings are distributed on the outer surface of the outer casing (4) at equal angles along the axial direction.

6. A co-extruded annular fuel rod of claim 5 wherein: the height of the turbulence wing (6) is equal to the distance between two adjacent annular fuel rods in the fuel assembly, and the two adjacent annular fuel rods can be limited through the turbulence wing (6).

7. A co-extruded annular fuel rod of claim 6 wherein: helium does not need to be filled in the fuel rod.

8. A co-extruded annular fuel rod of claim 7 wherein: the annular fuel core (5) is a dispersion fuel.

9. A co-extruded annular fuel rod of claim 7 wherein: the annular fuel core (5) is metal fuel.

10. A co-extruded annular fuel rod as claimed in any one of claims 1 to 9, wherein: the reactor is suitable for pressurized water reactors, fast reactors, low-temperature heat supply reactors, space reactors, boiling water reactors, micro-reactors, zero-power reactors, heavy water reactors, power reactors and marine power reactor types.