CN115497644A

CN115497644A - Guide pipe and fuel assembly

Info

Publication number: CN115497644A
Application number: CN202211243106.5A
Authority: CN
Inventors: 温国义; 刘新利; 韩超; 李承霖; 王光辉; 俞潇; 王亚松; 刘原君; 吴晓波; 赵猛
Original assignee: National Nuclear Demonstration Power Plant Co ltd
Current assignee: National Nuclear Demonstration Power Plant Co ltd
Priority date: 2022-10-11
Filing date: 2022-10-11
Publication date: 2022-12-20

Abstract

The invention belongs to the technical field of nuclear fuel assemblies of nuclear power stations, and discloses a guide tube and a fuel assembly, wherein the guide tube comprises a plurality of tube parts and a plurality of buffer parts, the tube parts are arranged at intervals, the buffer parts are communicated with the tube parts and play a damping role on a rapidly falling control rod, the buffer parts are arranged in plurality, the buffer parts are respectively clamped between every two adjacent tube parts, and the buffer parts and the tube parts are integrally formed. Meanwhile, the structural rigidity of the guide pipe is enhanced, the anti-seismic performance is high, and the problem of risk of failure of a framework of the fuel assembly caused by expansion joint or welding failure of the guide pipe and the buffer pipe is solved.

Description

Guide pipe and fuel assembly

Technical Field

The invention relates to the technical field of nuclear fuel assemblies of nuclear power stations, in particular to a guide pipe and a fuel assembly.

Background

The nuclear fuel assembly comprises a guide pipe, a positioning frame, a pipe seat, a plurality of fuel rods and other components, wherein the guide pipe is a bearing part of the nuclear fuel assembly, provides coolant flow for the fuel rods, provides an insertion channel for fuel related assemblies, and provides hydraulic buffering for the falling of a control rod during the emergency shutdown of a reactor.

At present, the guide tube structure of a nuclear fuel assembly mainly comprises an AP1000 type guide tube and an AFA3G type guide tube, wherein the outer diameter of the AFA3G type guide tube is kept unchanged, the tube diameter of the upper end is large, the tube diameter of the lower end is small, and sufficient annular gaps exist after the assemblies such as control rods are inserted, so that the control rods can be rapidly inserted when a reactor stops, sufficient coolant flow can be ensured, and the difficulty of a rolling process is large. AP1000 type stand pipe is the pipe-in-pipe structure, the buffer tube is arranged in the stand pipe, both cooperate welded connection through respective end plug, however, AP1000 type stand pipe need earlier with bottom locating rack sleeve pipe expanded joint, then insert inside buffer tube and expand and connect and form the stand pipe part, there is the expanded joint to lose efficacy and lead to the risk that the fuel assembly skeleton became invalid, and in the assembling process, the location cooperation degree of difficulty is big, buffer tube and stand pipe disalignment, lead to the inside buffer tube slope of stand pipe, when the control rod falls excellent and mentions, the control rod is abraded to the buffer tube port, influence the life of control rod.

Therefore, a need exists for a guide tube and fuel assembly that addresses the above-mentioned problems.

Disclosure of Invention

The invention aims to provide a guide pipe which is simple in structure and quick to assemble, assembly and welding of the guide pipe and a buffer pipe are omitted, manufacturing cost and personnel operation time are reduced, structural rigidity of the guide pipe is enhanced, and the problem of risk of failure of a fuel assembly framework caused by expansion joint or welding failure of the guide pipe and the buffer pipe is solved.

In order to solve the problems in the prior art, the invention adopts the following technical scheme:

a guide tube, comprising:

a plurality of pipe parts which are arranged at intervals;

the buffer part, the buffer part communicate in pipe fitting portion, the quantity of buffer part has a plurality ofly, and is a plurality of buffer part presss from both sides respectively and locates every adjacent two between the pipe fitting portion, the buffer part with pipe fitting portion integrated into one piece.

Preferably, the buffer part comprises a first connecting end, a second connecting end and a middle buffer section, the middle buffer section is connected between the first connecting end and the second connecting end, and the first connecting end and the second connecting end are respectively integrally formed with the two adjacent pipe fitting parts.

Preferably, the outer circumferential surface of the intermediate buffer section is arranged in parallel with the outer circumferential surface of the pipe part in the axial direction of the pipe part.

Preferably, the extending direction of the first connecting end and the extending direction of the second connecting end form an acute angle a with the outer peripheral surface of the pipe fitting part.

Preferably, the acute angle a is equal to 45 degrees.

Preferably, the guide tube further includes an end plug, the end plug is mounted in the opening of the tube portion, an outer peripheral surface of the end plug abuts against an inner peripheral surface of the tube portion, and the end plug is used for plugging the tube portion.

Preferably, the end plug is welded to the tube portion.

Preferably, the inner diameter of the pipe part is equal to the inner diameter of the buffer part, and the wall thickness of the pipe part is equal to the wall thickness of the buffer part.

Preferably, the pipe part and the buffer part are made of a zirconium alloy material.

To achieve the above object, the present invention further provides a fuel assembly including the above guide tube.

The beneficial effects of the invention are as follows:

according to the guide tube provided by the invention, the number of the tube parts is multiple, the tube parts are arranged at intervals, the buffer parts play a damping role in a control rod which quickly falls down, the number of the buffer parts is multiple, and the buffer parts are respectively clamped between every two adjacent tube parts. Buffering portion and pipe fitting portion integrated into one piece, simple structure, the equipment is swift, has saved the assembly and the welding of stand pipe and buffer tube, reduces manufacturing cost and personnel operating time to solved and leaded to the buffer tube slope because the location fit degree of difficulty is big in the assembling process, avoided control rod and buffer tube port abrasion, improved control rod's life. Meanwhile, the structural rigidity of the guide pipe is enhanced, the anti-seismic performance is high, and the problem of risk of failure of a framework of the fuel assembly caused by expansion joint or welding failure of the guide pipe and the buffer pipe is solved.

The fuel assembly provided by the invention comprises the guide pipe, the guide pipe is simple in structure and quick to assemble, the assembly and welding of the guide pipe and the buffer pipe are omitted, and the manufacturing cost and the personnel operation time of the fuel assembly are reduced.

Drawings

FIG. 1 is a schematic structural view of a guide tube according to an embodiment of the present invention;

FIG. 2 is an enlarged view of a portion of FIG. 1 at A;

FIG. 3 is a cross-sectional view of a guide tube in an embodiment of the present invention;

fig. 4 is a schematic structural view of the pipe part and the buffer part in the embodiment of the present invention.

Reference numerals:

1. a pipe section;

2. a buffer section; 21. a first connection end; 22. a second connection end; 23. a middle buffer section;

3. an end plug.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some structures related to the present invention are shown in the drawings, not all of them.

In the description of the present invention, unless otherwise explicitly specified or limited, the terms "connected," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in a specific case to those of ordinary skill in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are used based on the orientations and positional relationships shown in the drawings, and are only for convenience of description and simplicity of operation, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.

In the prior art, the outer diameter of the AFA3G type guide pipe is kept unchanged, the pipe diameter of the upper end is large, the pipe diameter of the lower end is small, and sufficient annular clearance exists after components such as control rods are inserted, so that the control rods can be quickly inserted when a reactor is stopped, sufficient coolant flow can be guaranteed, and the difficulty of a rolling process is large. AP1000 type stand pipe is the pipe-in-pipe structure, the buffer tube is arranged in the stand pipe, both cooperate welded connection through respective end plug 3, however, AP1000 type stand pipe need earlier with bottom locating rack sleeve pipe expanded joint, then insert inside buffer tube and expand and connect and form the stand pipe part, there is the risk that the expanded joint became invalid and lead to the fuel assembly skeleton to become invalid, and in the assembling process, the location cooperation degree of difficulty is big, buffer tube and stand pipe disalignment, lead to the inside buffer tube slope of stand pipe, when the control rod falls excellent and mentions, the control rod is abraded to the buffer tube port, influence the life of control rod. Therefore, the guide pipe is provided in the embodiment, the structure is simple, the assembly is rapid, the assembly and welding of the guide pipe and the buffer pipe are omitted, the manufacturing cost and the operation time of personnel are reduced, meanwhile, the structural rigidity of the guide pipe is enhanced, and the problem that the expansion connection or welding failure of the guide pipe and the buffer pipe causes the risk of failure of the framework of the fuel assembly is avoided.

As shown in fig. 1 to 4, in the present embodiment, the guide tube includes a tube part 1 and a buffer part 2. Wherein, the quantity of pipe fitting portion 1 has a plurality ofly, and a plurality of pipe fitting portion 1 intervals set up, and buffer 2 communicates in pipe fitting portion 1, and buffer 2's quantity has a plurality ofly, and a plurality of buffers 2 press from both sides respectively and locate between every two adjacent pipe fitting portions 1, and buffer 2 and pipe fitting portion 1 integrated into one piece. Specifically, be provided with buffer portion 2 between every two adjacent pipe fittings portion 1, play the damping effect to the control rod that falls fast, buffer portion 2 and the design of pipe fittings portion 1 integrated into one piece, simple structure, the equipment is swift, has saved the assembly and the welding of stand pipe and buffer tube, reduces manufacturing cost and personnel operating time to solved and lead to the buffer tube slope because the location fit degree of difficulty is big in the assembling process, avoided control rod and buffer tube port abrasion, improved control rod's life. Meanwhile, the structural rigidity of the guide pipe is enhanced, the anti-seismic performance is high, and the problem of risk of failure of a framework of the fuel assembly caused by expansion joint or welding failure of the guide pipe and the buffer pipe is solved.

Further, with continued reference to fig. 1 to 4, the buffer portion 2 includes a first connection end 21, a second connection end 22, and an intermediate buffer section 23, the intermediate buffer section 23 is connected between the first connection end 21 and the second connection end 22, and the first connection end 21 and the second connection end 22 are respectively integrally formed with two adjacent pipe fitting portions 1. Specifically, the buffer part 2 is in a shape of Chinese character 'ao', and plays a damping role in the control rod which falls down quickly, the middle buffer section 23 is integrally formed with the first connecting end 21 and the second connecting end 22 respectively, and meanwhile, the first connecting end 21 and one of the two adjacent pipe fitting parts 1 are integrally formed, and the second connecting end 22 and the other one of the two adjacent pipe fitting parts 1 are integrally formed, so that the assembly is reduced, and the manufacturing efficiency is improved.

Further, with continued reference to fig. 1-4, along the axial direction of the pipe fitting part 1, the outer peripheral surface of the middle buffer section 23 is parallel to the outer peripheral surface of the pipe fitting part 1, when the control rod falls down quickly in the guide pipe, the buffer part 2 has a certain damping effect on the control rod, and simultaneously, the axial line of the middle buffer section 23 is coaxial with the axial line of the pipe fitting part 1, so that the pipe fitting part 1 and the middle buffer section 23 can move along the same axial direction, and the phenomenon that the buffer part 2 and the pipe fitting part 1 are not coaxial and the guide pipe is inclined is avoided.

Further, with continued reference to fig. 1-4, the extending direction of the first connecting end 21 and the extending direction of the second connecting end 22 both form an acute angle a with the outer circumferential surface of the pipe fitting part 1. Specifically, the first connection end 21 and the second connection end 22 are both at an acute angle a with the pipe part 1, and the acute angle a is 45 degrees.

Further, with reference to fig. 1 to 4, the guide tube further includes an end plug 3, the end plug 3 is mounted in the opening of the tube portion 1, an outer circumferential surface of the end plug 3 abuts against an inner circumferential surface of the tube portion 1, and the end plug 3 is used for plugging the tube portion 1. Specifically,

end plug

3 and 1 welded connection of pipe fitting portion, the spot welding is fixed after pipe fitting portion 1 and end plug 3 adopt the form of pressing the stopper to be connected, need not to carry out full weld, reduces bonding wire length, improves connection quality, and the leakproofness is good.

Further, with continued reference to fig. 1-4, the inner diameter of the pipe part 1 is equal to the inner diameter of the buffer part 2, and the wall thickness of the pipe part 1 is equal to the wall thickness of the buffer part 2.

Further, with continued reference to fig. 1-4, the pipe section 1 and the buffer section 2 are made of a zirconium alloy material. Specifically, zirconium has a very low thermal neutron absorption cross section, high hardness, ductility and corrosion resistance, and zirconium alloy has good corrosion resistance, moderate mechanical properties, a lower atomic thermal neutron absorption cross section in high-temperature and high-pressure water and steam, and has good compatibility with nuclear fuel, so that zirconium alloy can be used as a core structure material of a water-cooled nuclear reactor, and is beneficial to high-burnup operation of fuel assemblies.

The embodiment also provides a fuel assembly, which comprises the guide pipe, and relates to the technical field of nuclear fuel assemblies of nuclear power stations, the guide pipe is simple in structure and quick to assemble, the guide pipe and the buffer pipe are omitted for assembly and welding, the manufacturing cost and the personnel operation time are reduced, meanwhile, the structural rigidity of the guide pipe is enhanced, and the guide pipe has high anti-seismic performance.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Numerous obvious variations, adaptations and substitutions will occur to those skilled in the art without departing from the scope of the invention. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. The stand pipe, its characterized in that includes:

a plurality of pipe fittings (1), wherein the number of the pipe fittings (1) is multiple, and the plurality of the pipe fittings (1) are arranged at intervals;

buffer portion (2), buffer portion (2) communicate in pipe fitting portion (1), there are a plurality ofly buffer portion (2), and is a plurality of buffer portion (2) press from both sides respectively and locate every adjacent two between pipe fitting portion (1), buffer portion (2) with pipe fitting portion (1) integrated into one piece.

2. The guide tube according to claim 1, wherein the buffer portion (2) includes a first connection end (21), a second connection end (22), and an intermediate buffer section (23), the intermediate buffer section (23) is connected between the first connection end (21) and the second connection end (22), and the first connection end (21) and the second connection end (22) are respectively integrally formed with adjacent two of the tube portions (1).

3. The guide tube according to claim 2, characterized in that the outer circumferential surface of the intermediate buffer section (23) is arranged in parallel with the outer circumferential surface of the tube part (1) in the axial direction of the tube part (1).

4. The guide tube according to claim 2, characterized in that the extension direction of the first connection end (21) and the extension direction of the second connection end (22) each form an acute angle a with the outer circumference of the tube part (1).

5. The guide tube of claim 4, wherein the acute angle A is equal to 45 degrees.

6. The guide tube according to claim 1, characterized in that the guide tube further comprises an end plug (3), the end plug (3) is mounted at the opening of the tube part (1), the outer circumferential surface of the end plug (3) abuts against the inner circumferential surface of the tube part (1), and the end plug (3) is used for plugging the tube part (1).

7. The guide tube according to claim 6, characterized in that the end plug (3) is welded to the tube part (1).

8. Guide tube according to any of claims 1-7, characterized in that the inner diameter of the tube part (1) is equal to the inner diameter of the buffer part (2) and that the wall thickness of the tube part (1) is equal to the wall thickness of the buffer part (2).

9. Guide tube according to any of claims 1-7, characterized in that the tube part (1) and the buffer part (2) are made of zirconium alloy material.

10. A fuel assembly comprising a guide tube according to any one of claims 1 to 9.