阅读说明：本技术 乏燃料除金属井及去除乏燃料上液态金属的方法 (Metal removing well for spent fuel and method for removing liquid metal on spent fuel ) 是由 周高飞 李海阳 蒋光煜 谭璞 赵剑刚 彭浩 张守杰 崔大伟 于 2020-12-18 设计创作，主要内容包括：本发明公开了一种乏燃料除金属井,包括：中空井本体；吊装组件,所述吊装组件用于带动待清洁乏燃料在所述中空经本体内部运动,所述乏燃料上具有液态金属；三相交变磁组件,用于提供与所述待清洁乏燃料运动方向相互垂直的三相交变磁场；电磁组件,用于提供电磁场,所述电磁组件为围绕所述中空井本体的内壁螺旋缠绕的通电线圈；所述电磁组件位于所述三相交变磁组件的下部。本发明还公开了一种去除乏燃料上液态金属的方法。(The invention discloses a spent fuel metal removing well, which comprises: a hollow well body; the hoisting assembly is used for driving the spent fuel to be cleaned to move in the hollow main body, and the spent fuel is provided with liquid metal; the three-phase alternating magnetic assembly is used for providing a three-phase alternating magnetic field which is vertical to the moving direction of the spent fuel to be cleaned; an electromagnetic assembly for providing an electromagnetic field, the electromagnetic assembly being an energized coil helically wound around an inner wall of the hollow well body; the electromagnetic assembly is located on the lower portion of the three-phase alternating magnetic assembly. The invention also discloses a method for removing the liquid metal on the spent fuel.)

1. A spent fuel demetallization well, comprising:

a hollow well body;

the hoisting assembly is used for driving the spent fuel to be cleaned to move in the hollow main body, and the spent fuel is provided with liquid metal;

the three-phase alternating magnetic assembly is used for providing a three-phase alternating magnetic field which is vertical to the moving direction of the spent fuel to be cleaned;

an electromagnetic assembly for providing an electromagnetic field, the electromagnetic assembly being an energized coil helically wound around an inner wall of the hollow well body;

the electromagnetic assembly is located on the lower portion of the three-phase alternating magnetic assembly.

2. The spent fuel metal-removing well according to claim 1, wherein the direction of the three-phase alternating magnetic field is a horizontal direction.

3. The spent fuel removing metal well according to claim 2, wherein the axial direction of the energized coil is a vertical direction.

4. The spent fuel metal removing well according to claim 1, wherein the ratio of the height of the alternating magnetic field to the height of the electromagnetic field is 1 (1.5-2.5).

5. The spent fuel metal removing well according to claim 1, wherein an inert gas purging device is arranged at the upper part of the electromagnetic assembly; preferably, the gas purging direction of the inert gas purging device is 30-45 degrees to the vertical direction; preferably, the inert gas purging device is arranged between the three-phase alternating magnetic assembly and the electromagnetic assembly.

6. The spent fuel removing metal well according to claim 1, wherein the bottom surface of the hollow well body is a funnel-shaped bottom surface.

7. The spent fuel metal-removing well according to claim 6, wherein the funnel-shaped bottom surface is centrally provided with a liquid metal outlet, and the liquid metal outlet is communicated with a liquid metal conduit outside the hollow well body.

8. A method for removing liquid metal on spent fuel, which is characterized by adopting the spent fuel metal removing well as defined in any one of claims 1-7, and comprising the following steps:

fixing the spent fuel to be cleaned on the hoisting assembly;

the spent fuel to be cleaned moves towards the bottom of the hollow well body and sequentially passes through a three-phase alternating magnetic field region formed by the three-phase alternating magnetic assembly and an electromagnetic field region formed by the electromagnetic assembly, so that liquid metal on the spent fuel to be cleaned moves to the inner side wall of the hollow well body and falls into the bottom of the hollow well body along the inner side wall.

9. The method for removing liquid metal from spent fuel according to claim 8, wherein the moving speed of the spent fuel to be cleaned in the three-phase alternating magnetic field area is 2.8m/s to 3.2 m/s.

10. The method for removing liquid metal from spent fuel according to claim 8, wherein the energizing current in the energizing coil of the electromagnetic assembly is 8A-10A.

11. The method for removing liquid metal from spent fuel according to claim 10, wherein the moving speed of the spent fuel to be cleaned in the electromagnetic field area is 2.8m/s to 3.2 m/s.

12. The method for removing liquid metal from spent fuel according to claim 8, wherein the method comprises the step of purging inert gas from top to bottom to the spent fuel metal removing well, and the purging pressure is 0.4MPa to 0.6 MPa.

Technical Field

The invention relates to the technical field of spent fuel post-treatment, in particular to a metal removing well for spent fuel and a method for removing liquid metal on the spent fuel.

Background

The use of nuclear power is a major breakthrough in the history of energy utilization of human beings, and nuclear fuel can generate high energy output which is incomparable with all other traditional fossil energy sources by utilizing the fission reaction of atomic nucleus, and the high energy output usually only needs to consume a small amount of nuclear fuel. Due to the low investment and high output, the utilization of nuclear energy is increasingly emphasized by human beings, and research and development in the field of nuclear energy are continuously increased, so that the nuclear energy has become an important energy component of many countries in the world today. However, nuclear power has high utilization value, and the possible harm caused by the nuclear power is also related to nuclear discoloration. In the process of using nuclear power, if serious accidents such as nuclear leakage and the like occur due to improper protection, serious nuclear pollution disasters will be brought to the environment around a nuclear power plant and even to all human beings, so how to ensure the safety of the nuclear power plant in the process of developing and utilizing the nuclear power is an extremely important research topic.

Spent fuel refers to nuclear fuel that has reached design burnup after undergoing a fission reaction in a reactor for a certain period of time and is unloaded from the reactor. Because the unloaded spent fuel still continues to generate decay heat for a long time, the conventional pressurized water reactor nuclear power plant usually stores the spent fuel assemblies in a spent fuel pool, cools the spent fuel by using a cooling system of the spent fuel pool, discharges the generated heat to a final heat sink (atmosphere, river, sea, etc.), and can perform post-treatment such as dissolution on the cooled spent fuel to extract valuable nuclides.

For a liquid metal fast reactor, after spent fuel is taken out of a reactor core, a metal coolant is attached to a spent fuel assembly, and the attached metal coolant brings potential safety hazards to storage of the spent fuel assembly, so that the spent fuel assembly needs to be cleaned before being placed into a spent fuel water pool for storage, and the metal coolant attached to the surface of the spent fuel assembly is removed. For the sodium-cooled fast reactor, the existing method is to remove the sodium coolant adhered to the surface of the spent fuel by argon-water vapor under the protection of argon after the spent fuel assembly is transferred to a spent fuel metal removing well, the water vapor can chemically react with sodium and generate H₂(ii) a The damaged spent fuel assembly is subjected to lead sealing treatment by using high-temperature lead in a high-temperature lead sealing well; h-containing gas discharged from spent fuel demetallization well₂Can be used as an index for distinguishing the degree of progress of the cleaning process by H₂The discharge amount of (c) determines the degree of cleaning. For a metal reactor with poor reaction capability, such as a lead-based fast reactor, because the chemical property of lead is different from that of sodium, the spent fuel cleaning method of the sodium-cooled fast reactor is not suitable for the lead-based fast reactor, and the current research on the lead-based fast reactor is still in a preliminary stage, and a suitable method for removing the lead coolant of the spent fuel is not provided.

Disclosure of Invention

Therefore, the problem that the lead on the lead-based reactor is difficult to remove is needed, and the metal removing well for the spent fuel and the method for removing the liquid metal on the spent fuel are provided.

A spent fuel demetallization well, comprising:

a hollow well body;

the hoisting assembly is used for driving the spent fuel to be cleaned to move in the hollow main body, and the spent fuel is provided with liquid metal;

the three-phase alternating magnetic assembly is used for providing a three-phase alternating magnetic field which is vertical to the moving direction of the spent fuel to be cleaned;

an electromagnetic assembly for providing an electromagnetic field, the electromagnetic assembly being an energized coil helically wound around an inner wall of the hollow well body;

the electromagnetic assembly is located on the lower portion of the three-phase alternating magnetic assembly.

In one embodiment, the direction of the three-phase alternating magnetic field is a horizontal direction.

In one embodiment, the axial direction of the energized coil is a vertical direction.

In one embodiment, the ratio of the height of the alternating magnetic field to the height of the electromagnetic field is 1 (1.5-2.5).

In one embodiment, an inert gas purging device is arranged at the upper part of the electromagnetic assembly; preferably, the gas purging direction of the inert gas purging device is 30-45 degrees to the vertical direction; preferably, the inert gas purging device is arranged between the three-phase alternating magnetic assembly and the electromagnetic assembly.

In one embodiment, the bottom surface of the hollow well body is a funnel-shaped bottom surface.

In one embodiment, the funnel-shaped bottom surface is centrally provided with a liquid metal outlet, which is in communication with a liquid metal conduit outside the hollow well body.

A method for removing liquid metal on spent fuel adopts the spent fuel metal removal well and comprises the following steps:

fixing the spent fuel to be cleaned on the hoisting assembly;

the spent fuel to be cleaned moves towards the bottom of the hollow well body and sequentially passes through a three-phase alternating magnetic field region formed by the three-phase alternating magnetic assembly and an electromagnetic field region formed by the electromagnetic assembly, so that liquid metal on the spent fuel to be cleaned moves to the inner side wall of the hollow well body and falls into the bottom of the hollow well body along the inner side wall.

In one embodiment, the moving speed of the spent fuel to be cleaned in the three-phase alternating magnetic field area is 2.8-3.2 m/s

In one embodiment, the energizing current in the energized coil of the electromagnetic assembly is 8A-10A.

In one embodiment, the moving speed of the spent fuel to be cleaned in the electromagnetic field area is 2.8-3.2 m/s

In one embodiment, the method comprises the step of purging inert gas from top to bottom to the metal removing well of the spent fuel, wherein the purging pressure is 0.4MPa to 0.6 MPa.

The invention utilizes the metal removing well of the spent fuel to remove the residual liquid metal on the spent fuel, the spent fuel component of the residual liquid metal enters the metal removing well of the spent fuel at a certain speed under the driving of the hoisting component, and the structure of the metal removing well of the spent fuel from top to bottom is as follows: three-phase alternating magnetic assemblies and electromagnetic assemblies. When the liquid metal attached to the spent fuel is driven by the hoisting assembly to cut the alternating magnetic field of the three-phase alternating magnetic field at a certain speed, induced current can be generated, the liquid metal with the induced current is attracted to the inner side wall of the spent fuel metal removing well under the action of the electromagnetic field, and the liquid metal is guided to the bottom of the spent fuel metal removing well along the inner side wall, so that the removal of the liquid metal on the spent fuel is realized.

In addition, an inert gas purging device is installed in the spent fuel metal removing well, high-pressure inert gas continuously purges the spent fuel assembly from top to bottom, so that part of liquid metal falls into the bottom of the spent fuel metal removing well under the action of gravity and inert gas purging, and the recovery efficiency of the liquid metal is improved by matching the action of a magnetic field.

Drawings

Fig. 1 is a schematic structural diagram of a spent fuel metal-removing well according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a three-phase AC magnetic assembly according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a three-phase ac magnetic assembly according to another embodiment of the present invention.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In the case of a nuclear fuel reactor, a certain amount of metal coolant adheres to the surface of spent fuel after it is removed from the core. In order to eliminate the adverse effects of galvanic corrosion and the like on the spent fuel assembly caused by the metal remained on the surface of the spent fuel during storage of the spent fuel, a spent fuel cleaning operation is required before the spent fuel is transferred to a spent fuel pool for storage, and the main purpose of the cleaning operation is to remove the metal and other impurities adhered on the surface of the spent fuel. At present, no generally feasible scheme is provided for the spent fuel cleaning process of the metal-based fast reactor.

For a lead-based reactor, the spent fuel assemblies are adhered with liquid lead mainly.

The invention combines the physical properties and cleaning process characteristics of liquid lead, and provides a feasible spent fuel cleaning process scheme: the cleaning process does not use cleaning agent, and an electromagnetic system is matched with the collection of the lead on the surface of the spent fuel. And the collection effect can be improved by being matched with the purging of inert gas.

Referring to fig. 1, an embodiment of the invention provides a metal removing well for spent fuel, including:

a hollow well body 100;

the lifting assembly is used for driving the spent fuel 300 to be cleaned to move in the hollow main body, and liquid metal is arranged on the spent fuel;

the three-phase alternating magnetic assembly 220 is used for providing a three-phase alternating magnetic field which is perpendicular to the moving direction of the spent fuel 300 to be cleaned;

an electromagnetic assembly 240 for providing an electromagnetic field, the electromagnetic assembly 240 being an energized coil spirally wound around an inner wall of the hollow well body 100;

the electromagnetic assembly 240 is located at a lower portion of the three-phase alternating magnetic assembly 220.

The invention utilizes the metal removing well of the spent fuel to remove the residual liquid metal on the spent fuel, the spent fuel component of the residual liquid metal enters the metal removing well of the spent fuel at a certain speed under the driving of the hoisting component, and the structure of the metal removing well of the spent fuel from top to bottom is as follows: a three-phase alternating magnetic assembly 220 and an electromagnetic assembly 240. When the liquid metal attached to the spent fuel is driven by the hoisting assembly to cut the alternating magnetic field of the three-phase alternating magnetic field at a certain speed, induced current can be generated, the liquid metal with the induced current is attracted to the inner side wall of the spent fuel metal removing well under the action of the electromagnetic field, and the liquid metal is guided to the bottom of the spent fuel metal removing well along the inner side wall, so that the removal of the liquid metal on the spent fuel is realized.

In some embodiments, the composition structure of the three-phase ac magnetic assembly 220, as shown in fig. 2 and fig. 3, may be a conventional structure forming a three-phase ac magnetic field, and will not be described herein again.

In some embodiments, the direction of the three-phase alternating magnetic field is a horizontal direction. (magnitude of magnetic field is sine function type)

In some embodiments, the axial direction of the energized coil is a vertical direction.

In some embodiments, the ratio of the height of the alternating magnetic field to the height of the electromagnetic field is 1 (1.5-2.5). Preferably 1: 2.

In some embodiments, an inert gas purge device 260 is disposed above the solenoid assembly 240. The inert gas purging device 260 is installed on the upper portion of the inner wall of the spent fuel metal removing well, the high-pressure inert gas continuously purges the spent fuel assembly from top to bottom, so that part of liquid metal falls into the bottom of the spent fuel metal removing well under the action of gravity and inert gas purging, is finally guided to leak to the liquid metal guide pipe 500 from the bottom, and then flows out of the liquid metal guide pipe 500. After reaching the basket 400 at the bottom of the metal removing well, the spent fuel is still for a period of time under the action of the inert gas purging, so as to carry out final cleaning and recovery on the residual liquid metal on the surface of the spent fuel assembly.

Inert gas refers to a gas corresponding to all group 0 elements on the periodic table of elements, also known as noble gases. They are colorless and odorless monatomic gases at normal temperature and pressure, and are difficult to chemically react. The inert gas may be any one gas selected from helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn, radioactive), (gas or) (Og, radioactive, artificial element).

Preferably, an included angle between the gas purging direction of the inert gas purging device 260 and the vertical direction is 30-45 degrees, so that the inert gas can be purged to spent fuel with liquid metal within the angle range, the purging direction is wide in radiation range, and the amount of the inert gas can be saved. The inert gas purging direction and the vertical direction form a certain angle, an extra purging force can be provided for the liquid metal on the basis of gravity and magnetic field force, and the liquid metal is promoted to be separated from the spent fuel under the action of the superposed force. Specifically, the included angle may be 30 °, 40 °, 45 °.

Preferably, the inert gas purging device 260 is disposed between the three-phase alternating magnetic assembly 220 and the electromagnetic assembly 240. The inert gas purging is mainly applied to the area moving in the electromagnetic field, so that the inert gas purging device 260 is arranged under the three-phase alternating magnetic field, and the purging force provided by the inert gas can be fully utilized to accelerate the dropping of the liquid metal.

In some embodiments, the bottom surface of the hollow well body 100 is a slope with two sides gradually inclined toward the center, forming a funnel-shaped bottom surface 120. The funnel shaped bottom surface 120 may be a curved surface that is concave towards the inside of the well. The height of the middle portion of the funnel-shaped bottom surface 120 is less than the height of the side portions.

In some embodiments, the center of the funnel-shaped bottom surface 120 may be provided with a liquid metal outlet, which is communicated with the liquid metal conduit 500 outside the hollow well body 100, and the liquid metal at the bottom of the spent fuel except the metal well is guided to the outside through a liquid metal pipe for collection.

In some embodiments, the bottom of the metal well is provided with a basket 400 for spent fuel, and when the spent fuel moves to the bottom of the hollow well body 100 along with the hoisting assembly, the spent fuel is received by the basket 400 for spent fuel in the metal well for spent fuel, so as to prevent the spent fuel from making secondary contact with the liquid metal cleaned from the bottom of the hollow well body 100. The spent fuel basket 400 may be disposed at the center of the bottom surface of the hollow well body 100, for example, at the middle of the funnel-shaped bottom surface 120. The spent fuel basket 400 is preferably a structure having a body without voids so that liquid metal from the bottom wash is prevented from seeping into the basket 400.

The embodiment of the invention also provides a method for removing liquid metal on the spent fuel, which adopts the spent fuel metal removing well and comprises the following steps:

fixing the spent fuel to be cleaned on the hoisting assembly;

the spent fuel to be cleaned moves towards the bottom of the hollow well body 100 and sequentially passes through the three-phase alternating magnetic field region formed by the three-phase alternating magnetic assembly 220 and the electromagnetic field region formed by the electromagnetic assembly 240, so that the liquid metal on the spent fuel to be cleaned moves to the inner side wall of the hollow well body 100 and falls into the bottom of the hollow well body 100 along the inner side wall.

In some embodiments, the energizing current in the energized coil of the electromagnetic assembly 240 is between 8A and 10A.

The moving speed of the spent fuel to be cleaned in the magnetic field is closely related to the removal of the liquid metal, and if the moving speed is too high, the magnetic field may reach the bottom of the well before the liquid metal is attracted to the inner side wall. If the moving speed is too slow, the induced current, which may be caused by cutting the magnetic induction lines, is too weak, so that the attraction force of the electromagnetic field to the liquid metal is insufficient to remove the liquid metal from the spent fuel.

In some embodiments, the moving speed of the spent fuel to be cleaned in the three-phase alternating magnetic field area is 2.8 m/s-3.2 m/s

In some embodiments, the moving speed of the spent fuel to be cleaned in the electromagnetic field area is 2.8 m/s-3.2 m/s

In some embodiments, the method comprises the step of purging inert gas from top to bottom to the spent fuel metal removal well, wherein the purging pressure is 0.4MPa to 0.6 MPa. For example, the pressure may be 0.4MPa, 0.45MPa, 0.5MPa0.55MPa or 0.6 MPa.

Preferably, when the spent fuel assembly is at rest in the lower portion of the spent fuel metal removing well, the power supply of the electromagnetic assembly is turned off, and the liquid metal collected in the electromagnetic field area is guided to the inclined surface of the bottom of the spent fuel metal removing well along the inner side wall and then guided to the liquid metal guide pipe 500.

The following specific scheme for removing liquid lead from the lead-based spent fuel is described as follows:

referring to fig. 1 and 2, the metal removing well for spent fuel includes: the hollow well comprises a hollow well body 100, a hoisting assembly, a three-phase alternating magnetic assembly 220 and an electromagnetic assembly 240. The hoisting assembly is used for driving the spent fuel 300 to be cleaned to move in the hollow channel body, and the spent fuel is provided with liquid metal. The three-phase alternating magnetic assembly 220 is used for providing a three-phase alternating magnetic field perpendicular to the moving direction of the spent fuel 300 to be cleaned. An electromagnetic assembly 240 for providing an electromagnetic field, the electromagnetic assembly 240 being an energized coil spirally wound around an inner wall of the hollow well body 100. The electromagnetic assembly 240 is located at a lower portion of the three-phase alternating magnetic assembly 220. The direction of the three-phase alternating magnetic field is the horizontal direction. The axial direction of the energized coil of the electromagnetic assembly 240 is the vertical direction. The ratio of the height of the alternating magnetic field to the height of the electromagnetic field is 1: 2. An inert gas purging device 260 is arranged between the three-phase alternating magnetic assembly 220 and the electromagnetic assembly 240. The gas purge direction of the inert gas purge device 260 was 40 ° from the vertical direction. The inert gas purged was argon. The bottom surface of the hollow well body 100 is a funnel-shaped bottom surface 120. The center of the funnel-shaped bottom surface 120 is provided with a liquid metal outlet, which communicates with the liquid metal conduit 500 outside the hollow well body 100. The method specifically comprises the following steps of: fixing the spent fuel to be cleaned on the hoisting assembly, enabling the spent fuel to be cleaned to move towards the bottom of the hollow well body 100 and sequentially pass through a three-phase alternating magnetic field region formed by the three-phase alternating magnetic assembly 220 and an electromagnetic field region formed by the electromagnetic assembly 240, so that the liquid metal on the spent fuel to be cleaned moves to the inner side wall of the hollow well body 100 and falls into the bottom of the hollow well body 100 along the inner side wall. The moving speed of the spent fuel to be cleaned in the three-phase alternating magnetic field area is 3 m/s. The energizing current in the energized coil of the electromagnetic assembly 240 is 10A. The moving speed of the spent fuel to be cleaned in the electromagnetic field area is 2.8 m/s. And blowing inert gas to the spent fuel metal removing well from top to bottom, wherein the blowing pressure is 0.5 MPa.

The spent fuel is hoisted from the reactor building to a spent fuel demetallization well arranged at the front end of the spent fuel pool and received by a spent fuel basket 400 in the spent fuel demetallization well. The spent fuel assembly with the residual liquid lead enters the spent fuel metal removing well at a certain speed under the driving of the hoisting assembly, and the structure of the spent fuel metal removing well from top to bottom is as follows: the device comprises a three-phase alternating magnetic field (when liquid lead cuts the alternating magnetic field at a certain speed, induced current is generated), an electromagnetic field (when the liquid lead which is introduced with the induced current is attracted to the inner wall of the metal well for removing the spent fuel under the action of the electromagnetic field, when a spent fuel assembly is still at the lower part of the metal well for removing the spent fuel, an electromagnetic field power supply is turned off, the liquid lead collected in an electromagnetic field area is led to the bottom of the metal well for removing the spent fuel along a groove of the electromagnetic field, and finally the liquid lead is led to a liquid lead. Meanwhile, the inert gas purging device 260 is installed on the upper portion of the inner wall of the spent fuel metal removing well, the high-pressure inert gas continuously purges the spent fuel assembly from top to bottom, so that part of the liquid lead falls into the bottom of the spent fuel metal removing well under the action of gravity and the inert gas purging, and finally is guided to leak to the liquid lead conduit from the bottom and then flows out of the liquid lead conduit. After reaching the basket 400 at the bottom of the metal removing well, the spent fuel is still for a period of time under the action of the inert gas purging, so as to carry out final cleaning and recovery on the liquid lead remained on the surface of the spent fuel assembly.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.