Irradiation device

Abstract

The invention discloses an irradiation device, relates to the technical field of research on reactor fuel irradiation, and mainly aims to create a neutron energy spectrum environment similar to a fast reactor in a thermal spectrum reactor so as to simulate an operation environment of a fast reactor fuel element in an actual reactor and carry out an irradiation test. According to the main technical scheme, the irradiation device comprises a positioning flange which is installed on a reactor top fixing structure of a research reactor; the fuel rod assembly and the positioning flange are relatively fixed; the neutron screen assembly is arranged outside the fuel rod assembly, an axial hollow channel is formed in the neutron screen assembly, and the fuel rod assembly is located in the hollow channel; the driving assembly is connected with the neutron screen assembly, and the driving assembly is used for driving the neutron screen assembly to rotate in the circumferential direction and / or move in the axial direction relative to the fuel rod assembly.

Description

Technical Field

[0001] The present application belongs to the technical field of research reactor fuel irradiation, and specifically relates to an irradiation device. Background Art

[0002] In recent years, nuclear energy development has received increasing attention, and fast neutron reactors (abbreviated as fast reactors), as the core part of the fourth-generation advanced nuclear energy system, are regarded as an important development direction of nuclear energy in the future due to their superior resource utilization and ability to reduce nuclear waste. In order to ensure the stable and safe operation of fast reactors, irradiation testing of the fuel elements used in them is a key link.

[0003] The operating environment of fast reactor fuel elements in an actual reactor is a special neutron spectrum environment. In order to simulate this environment and conduct irradiation tests on fuel elements, a research reactor with a similar neutron spectrum is usually required. However, due to the high cost of building and operating fast neutron research reactors, such research reactors are very scarce both at home and abroad, resulting in a serious shortage of irradiation test resources for fast reactor fuel elements.

[0004] Traditional thermal spectrum research reactors cannot be directly used for irradiation tests of fast reactor fuel elements because their neutron energy spectra are significantly different from those of fast reactors. Summary of the invention

[0005] In view of this, the present application provides an irradiation device, the main purpose of which is to create a neutron spectrum environment similar to that of a fast reactor in a thermal spectrum reactor, so as to simulate the operating environment of fast reactor fuel elements in an actual reactor and conduct irradiation tests.

[0006] In order to achieve the above objectives, this application mainly provides the following technical solutions:

[0007] The present application provides an irradiation device, comprising:

[0008] A positioning flange, wherein the positioning flange is mounted on a top fixed structure of the research reactor;

[0009] A fuel rod assembly, wherein the fuel rod assembly is relatively fixed to the positioning flange;

[0010] A neutron screen assembly, wherein the neutron screen assembly is arranged outside the fuel rod assembly, an axial hollow channel is arranged inside the neutron screen assembly, and the fuel rod assembly is located in the hollow channel;

[0011] A drive assembly is connected to the neutron screen assembly, and is used to drive the neutron screen assembly to rotate circumferentially and / or move axially relative to the fuel rod assembly.

[0012] Optionally, the fuel rod assembly comprises:

[0013] an inner target tube and a plurality of fuel rods;

[0014] An upper cover is provided at one end of the inner target tube close to the positioning flange, and an air outlet hole is provided on the upper cover, and the air outlet hole is used to connect the air outlet pipe; a lower cover is provided at one end of the inner target tube away from the positioning flange, and an air inlet hole is provided on the lower cover, and the air inlet hole is used to connect the air inlet pipe;

[0015] A plurality of the fuel rods are arranged in the inner target tube, positioning blocks are respectively arranged at both ends of the plurality of fuel rods, and a connecting block is arranged between two adjacent fuel rods, and a through hole is opened at the center of the positioning block and the connecting block, and the through hole is used for gas to pass through.

[0016] Optionally, the inner target tube is a variable diameter tube, and the inner diameter of the inner target tube changes in a step-like manner along the first direction.

[0017] Optionally, at least two air inlet holes are provided, each of the air inlet holes is connected to one of the air inlet pipes in a one-to-one correspondence, and different air inlet pipes are used to pass different types of the gases.

[0018] Optionally, the neutron screen assembly includes:

[0019] Inner casing, outer casing and multi-segment neutron shield;

[0020] The inner sleeve is arranged in the outer sleeve, and the two ends of the outer sleeve and the inner sleeve are sealed and connected by a cover plate. The outer side surface of the inner sleeve, the inner side surface of the outer sleeve and the two cover plates constitute a sealed cavity, and multiple sections of the neutron screen are sequentially arranged in the sealed cavity along the axial direction.

[0021] Optionally, each section of the neutron shield is made of different materials, and each section of the neutron shield has a different thickness.

[0022] Optionally, the driving assembly comprises:

[0023] Driving part, transmission part and connecting part;

[0024] The first end of the connecting part is connected to the transmission part, the second end of the connecting part is connected to the neutron screen assembly, and the transmission part is also connected to the driving part. The driving part is used to drive the transmission part to move, so as to drive the neutron screen assembly to rotate circumferentially and / or move axially through the connecting part.

[0025] Optionally, the driving part includes a first driving unit, and the transmission part includes a first cylindrical gear, a second cylindrical gear, a guide rod and a guide tube;

[0026] The driving end of the first driving unit is connected to the first cylindrical gear, the second cylindrical gear is meshed with the first cylindrical gear, and the guide rod is connected to the second cylindrical gear;

[0027] The first driving unit is used to drive the first cylindrical gear to rotate, and then drive the guide rod to rotate with the axis of the second cylindrical gear as the rotation center through the second cylindrical gear;

[0028] At least a portion of the guide rod is movably disposed in the guide tube, and the guide tube is connected to the connecting portion, thereby driving the connecting portion to rotate synchronously.

[0029] Optionally, the driving part further includes a second driving unit, and the transmission part further includes a bevel gear set, a screw shaft and a driven shaft;

[0030] The driving end of the second driving unit is connected to the input end of the bevel gear set, the output end of the bevel gear set is connected to the screw shaft, and the screw shaft is matched with the driven shaft through a pipe thread;

[0031] The second driving unit is used to drive the bevel gear set to operate, so that the screw shaft drives the driven shaft to move axially, and the driven shaft is connected to the connecting part to drive the connecting part to move axially.

[0032] Optionally, the connecting portion includes a connecting flange and a connecting pipe, the connecting flange is used to fix the guide tube, the driven shaft and the connecting pipe, and one end of the connecting pipe away from the connecting flange is connected to the neutron screen assembly.

[0033] By means of the above technical solution, the present application has at least the following beneficial effects:

[0034] The irradiation device provided in the embodiment of the present application can create a neutron spectrum environment that is locally similar to that of a fast reactor in a thermal spectrum research reactor by setting a neutron shield assembly, thereby making full use of existing thermal spectrum research reactor resources, reducing the cost of fast reactor fuel element irradiation testing, promoting the research, verification and engineering application of fast reactor fuel technology, and further strengthening the research and development process of fast reactor fuel. At the same time, by setting a drive assembly, the neutron shield assembly can be driven to rotate circumferentially and / or move axially relative to the fuel rod assembly, thereby changing the flux distribution of neutrons, so that the neutron spectrum at the position of the fuel rod assembly is closer to the neutron spectrum of the fast reactor, so that the irradiation condition of the fuel element in the thermal spectrum research reactor is closer to the actual condition in the fast reactor, which is helpful to more realistically study the performance changes of the fast reactor fuel element during the irradiation process, avoiding the problem of large deviation between the test data and the actual fast reactor operation condition due to excessive differences in the neutron spectrum, and providing more reliable data support for the research and development of fast reactor fuel. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic structural diagram of an irradiation device according to an optional embodiment of the present application;

[0036] Figure 2 This is a schematic structural diagram of a fuel rod assembly of an optional embodiment of the present application;

[0037] Figure 3 This is a schematic structural diagram of a neutron screen assembly of an optional embodiment of the present application;

[0038] Figure 4 This is a schematic diagram of the structure of a drive assembly of an optional embodiment of the present application.

[0039] The reference numerals are:

[0040] 1. Positioning flange; 2. Fuel rod assembly; 21. Inner target tube; 22. Fuel rod; 23. Upper cover; 231. Air outlet; 24. Lower cover; 241. Air inlet; 25. Positioning block; 26. Connecting block; 3. Neutron screen assembly; 31. Inner sleeve; 32. Outer sleeve; 33. Neutron screen; 34. Cover plate; 4. Driving assembly; 41. Driving part; 411. First driving unit; 412. Second driving unit; 42. Transmission part; 421. First cylindrical gear; 422. Second cylindrical gear; 423. Guide rod; 424. Guide tube; 425. Bevel gear set; 426. Screw shaft; 427. Driven shaft; 43. Connecting part; 431. Connecting flange; 432. Connecting tube. DETAILED DESCRIPTION

[0041] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0042] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0043] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0044] The preferred embodiments of the present application are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present application and are not used to limit the present application.

[0045] See also Figures 1 to 4 As shown, according to an embodiment of the present application, an irradiation device is provided, including: a positioning flange 1, which is installed on the fixed structure at the top of the research reactor; a fuel rod assembly 2, which is relatively fixed to the positioning flange 1; a neutron screen assembly 3, which is arranged outside the fuel rod assembly 2, and an axial hollow channel is arranged inside the neutron screen assembly 3, and the fuel rod assembly 2 is located in the hollow channel; a driving assembly 4, which is connected to the neutron screen assembly 3, and is used to drive the neutron screen assembly 3 to rotate circumferentially and / or move axially relative to the fuel rod assembly 2.

[0046] In this embodiment, by setting the neutron shield assembly 3, a neutron spectrum environment that is locally close to that of a fast reactor can be created in the thermal spectrum research reactor, thereby making full use of the existing thermal spectrum research reactor resources, reducing the cost of fast reactor fuel element irradiation testing, promoting the research, verification and engineering application of fast reactor fuel technology, and further strengthening the research and development process of fast reactor fuel. At the same time, by setting the drive assembly 4, the neutron shield assembly 3 can be driven to rotate circumferentially and / or move axially relative to the fuel rod assembly 2, thereby changing the flux distribution of neutrons, so that the neutron spectrum at the position of the fuel rod assembly 2 is closer to the neutron spectrum of the fast reactor, so that the irradiation condition of the fuel element in the thermal spectrum research reactor is closer to the actual condition in the fast reactor, which is helpful to more realistically study the performance changes of the fast reactor fuel element during the irradiation process, avoiding the problem of large deviation between the test data and the actual fast reactor operation condition due to the large difference in the neutron spectrum, and providing more reliable data support for the research and development of fast reactor fuel.

[0047] Among them, the positioning flange 1 is the key component for connecting the entire irradiation device with the research reactor. Its main function is to fix the irradiation device to the fixed structure on the top of the research reactor to ensure that the irradiation device is stable and immobile during the irradiation process. In addition, an opening is designed in the middle of the positioning flange 1, which is mainly used to introduce the air inlet and outlet pipes.

[0048] Among them, the fuel rod assembly 2 is the core part of the irradiation, and contains the fuel used for the irradiation test. In this embodiment, the relative fixation of the fuel rod assembly 2 and the positioning flange 1 can be achieved by means of the traction effect of the air inlet pipe and the air outlet pipe. Specifically, the air inlet pipe and the air outlet pipe passing through the positioning flange 1 can be connected to the corresponding parts of the fuel rod assembly 2 respectively. By reasonably designing the installation position, direction and connection method of the air inlet pipe and the air outlet pipe, and utilizing the traction function of the air inlet pipe and the air outlet pipe, the fuel rod assembly 2 maintains a stable position relationship relative to the positioning flange 1, thereby ensuring that the fuel rod assembly 2 will not be displaced during the operation of the entire irradiation device, and ensuring the accuracy and stability of the irradiation test.

[0049] Among them, the neutron screen assembly 3 is arranged outside the fuel rod assembly 2, and the neutron screen assembly 3 has an axial hollow channel inside, and the fuel rod assembly 2 is located in the hollow channel. The main function of the neutron screen assembly 3 is to adjust the flux and energy spectrum of neutrons. It should be noted that the neutron screen assembly 3 is like a "neutron filter". The neutron energy spectrum in the thermal spectrum research reactor is different from that of the fast reactor. The neutron screen assembly 3 can block some unnecessary neutrons and allow neutrons that are more in line with the fast reactor energy spectrum characteristics to pass through, thereby creating a local neutron energy spectrum environment similar to that of the fast reactor in the hollow channel, so that the fuel rod assembly 2 can be irradiated in a screened neutron environment.

[0050] Among them, the driving assembly 4 is connected to the neutron shield assembly 3, and the function of the driving assembly 4 is to drive the neutron shield assembly 3 to rotate circumferentially and / or move axially relative to the fuel rod assembly 2. In this embodiment, on the one hand, the driving assembly 4 can only drive the neutron shield assembly 3 to rotate circumferentially relative to the fuel rod assembly 2; on the other hand, the driving assembly 4 can only drive the neutron shield assembly 3 to move axially relative to the fuel rod assembly 2. In addition, the driving assembly 4 can also drive the neutron shield assembly 3 to rotate circumferentially and move axially relative to the fuel rod assembly 2 at the same time. It should be noted that when the driving assembly 4 drives the neutron shield assembly 3 to rotate circumferentially, the neutron shield assembly 3 is like a rotating sieve, which changes the angle at which neutrons enter the hollow channel. For example, different rotation angles may cause neutrons to enter the hollow channel at different incident angles, thereby changing the distribution of neutron flux around the fuel rod assembly 2; when the driving assembly 4 drives the neutron shield assembly 3 to move axially, the position of the fuel rod assembly 2 in the hollow channel can be changed. This means that the neutron environment to which the fuel rod assembly 2 is subjected inside the neutron shield assembly 3 can be changed dynamically. For example, moving the fuel rod assembly 2 to a different position in the hollow channel may cause changes in the neutron flux and energy spectrum at the location of the fuel rod assembly 2 due to structural differences in the axial direction of the neutron shield assembly 3 (such as changes in the thickness and composition of the neutron shield 33 material), thereby providing researchers with a means to flexibly adjust the irradiation conditions.

[0051] In some possible implementations disclosed in this application, see Figure 2 As shown, the fuel rod assembly 2 includes: an inner target tube 21 and a plurality of fuel rods 22; an upper cover 23 is provided at one end of the inner target tube 21 close to the positioning flange 1, and the upper cover 23 is provided with an air outlet hole 231, and the air outlet hole 231 is used to connect the air outlet pipe, and a lower cover 24 is provided at one end of the inner target tube 21 away from the positioning flange 1, and the lower cover 24 is provided with an air inlet hole 241, and the air inlet hole 241 is used to connect the air inlet pipe; a plurality of fuel rods 22 are arranged in the inner target tube 21, and positioning blocks 25 are respectively provided at both ends of the plurality of fuel rods 22, and a connecting block 26 is provided between two adjacent fuel rods 22, and through holes are provided at the centers of the positioning block 25 and the connecting block 26, and the through holes are used to allow gas to pass through.

[0052] In this embodiment, a stable gas circulation channel is formed by respectively setting an air inlet hole 241 and an air outlet hole 231 on the upper and lower covers 24 of the inner target tube 21, and connecting the air inlet pipe and the air outlet pipe. During the irradiation process, the fuel rod assembly 2 generates heat, and the gas can circulate through this channel to take away the heat, thereby effectively preventing the fuel rod assembly 2 from being damaged due to overheating. For example, a large amount of heat is generated during some nuclear reactions, and the gas circulation system acts as a radiator to maintain the fuel rod assembly 2 within a suitable temperature range.

[0053] The inner target tube 21 provides a relatively closed accommodation space for the fuel rod 22 , which plays a role in protecting and limiting the position of the fuel rod 22 .

[0054] Specifically, an upper cover 23 is provided at one end of the inner target tube 21 close to the positioning flange 1, and the upper cover 23 is a closed component of the inner target tube 21 at one end close to the positioning flange 1. The upper cover 23 is provided with an air outlet 231, and the air outlet 231 is used to connect the air outlet pipe. When the entire irradiation device is in operation, the inner target tube 21 may have gas that needs to be discharged due to various circumstances (such as some gaseous substances generated by the reaction of the fuel rod 22 or gas introduced for the purpose of heat dissipation, etc.). At this time, the air outlet 231 can be used as a channel for gas discharge, and by connecting with the air outlet pipe, the gas is guided to other parts of the device for subsequent treatment. At the same time, a lower cover 24 is provided at one end of the inner target tube 21 away from the positioning flange 1, and the lower cover 24 also plays the role of closing the inner target tube 21. The lower cover 24 is provided with an air inlet 241, and the air inlet 241 is used to connect the air inlet pipe. During the irradiation process, in order to achieve certain functions (such as introducing cooling gas for heat dissipation, or to maintain a certain gas environment in the inner target tube 21, etc.), it is necessary to transport gas from the outside to the inner target tube 21. The air inlet hole 241 can serve as an air inlet channel, and by being connected to the air inlet pipe, the external gas can smoothly enter the inner target tube 21.

[0055] The fuel rod 22 is a core component for nuclear reactions and other related processes during the entire irradiation process. Specifically, the fuel rod 22 produces a series of reactions under conditions such as neutron irradiation, and its reaction conditions are the focus of research and monitoring. In this embodiment, a plurality of fuel rods 22 are provided, and the plurality of fuel rods 22 are sequentially arranged in the inner target tube 21 along the axial direction to ensure that each fuel rod 22 can be irradiated uniformly and effectively.

[0056] Among them, a positioning block 25 is provided between one of the multiple fuel rods 22 close to the upper cover 23 and the upper cover 23, and a positioning block 25 is also provided between one of the multiple fuel rods 22 close to the lower cover 24 and the lower cover 24. It can be understood that by providing the positioning block 25, the accurate axial position of the fuel rod 22 in the inner target tube 21 can be ensured, and the axial movement of the fuel rod 22 during the irradiation process can be prevented. At the same time, by providing the positioning block 25, the accurate radial position of the fuel rod 22 in the inner target tube 21 can be ensured, and the radial movement of the fuel rod 22 during the irradiation process can be prevented, which occupies the gas channel.

[0057] Among them, a connection block 26 is provided between two adjacent fuel rods 22 in the plurality of fuel rods 22. The connection block 26 is used to divide the area in the inner target tube 21 into different fuel rod 22 cavities. Each fuel rod 22 cavity provides a relatively independent and stable operating environment for the fuel rod 22 contained therein, which helps to more accurately monitor the irradiation of each fuel rod 22. It is understandable that researchers can obtain detailed data of each fuel rod 22 during the irradiation process, such as neutron flux, fission product generation, etc., by setting corresponding sensors in different cavities. This is conducive to in-depth analysis of the performance of a single fuel rod 22 and avoids the influence of mutual interference between adjacent fuel rods 22 on data accuracy.

[0058] Among them, the positioning block 25 and the connecting block 26 are both provided with through holes at their centers, which allow gas to smoothly enter the cavities of multiple fuel rods 22, thereby achieving effective protection and stable operation of the fuel rods 22. When the cooling gas enters the inner target tube 21 from the air inlet 241, it will flow between the cavities of each fuel rod 22. Due to the obstruction of the connecting block 26, the flow path of the gas in each cavity is relatively independent, which can more efficiently take away the heat generated by the fuel rod 22, thereby ensuring that each fuel rod 22 can work at a suitable temperature and reducing the potential risks caused by local overheating.

[0059] In the above embodiment, the inner target tube 21 is a variable diameter tube, and the inner diameter of the inner target tube 21 changes in a step-like manner along the first direction.

[0060] In this embodiment, after the gas enters the inner target tube 21 from the gas inlet hole 241, the flow rate and flow direction of the gas will change when passing through the area where the inner diameter changes. For example, in the area where the tube diameter becomes smaller, the gas flow rate will increase, which helps to enhance the convective heat exchange between the gas and the fuel rod 22. The accelerated gas flow rate can more efficiently take away the heat generated by the fuel rod 22, improve the heat dissipation efficiency, and prevent the fuel rod 22 from being affected by overheating or damaged. Moreover, this structure with a changing inner diameter can guide the gas to form a specific flow path in different tube diameter areas, so that the gas is more evenly distributed around the fuel rod 22. When the gas passes through the area where the inner diameter changes stepwise, it will produce an effect similar to a turbulent flow, which prompts the gas to better contact various parts of the fuel rod 22, avoid the "dead corner" of gas flow, further optimize the heat exchange process, and ensure that each fuel rod 22 can be irradiated in a good temperature environment.

[0061] The inner diameter of the inner target tube 21 is not a fixed value, but changes along a certain direction (defined as a first direction). The change is not a random continuous change, but a step-like change.

[0062] Specifically, the first direction may be any axial direction of the inner target tube 21. When observing the inner target tube 21 along the first direction, it is found that the inner diameter of the inner target tube 21 suddenly increases or decreases, forming a step-like shape. For example, in a certain section of the inner target tube 21, the inner diameter may be a smaller fixed value, and then after passing through a transition area, the inner diameter suddenly increases to another fixed value, and then may maintain this larger inner diameter for a period of time, and then the inner diameter decreases again. This step-like change in inner diameter may be regular, or it may be determined according to the specific design requirements of the irradiation device, and this embodiment does not limit this.

[0063] In the above embodiments, see Figure 2 As shown, at least two air inlet holes 241 are provided, each air inlet hole 241 is connected to an air inlet pipe in a one-to-one correspondence, and different air inlet pipes are used to pass different types of gases.

[0064] In this embodiment, at least two gas inlet holes 241 are provided, and each gas inlet hole 241 is connected to a corresponding gas inlet pipe for introducing different types of gases, so that a variety of different gases can be introduced into the fuel rod assembly 2. During the nuclear irradiation process, different gas environments may be required according to the experimental purpose or the performance requirements of the fuel rod 22. For example, sometimes helium needs to be introduced for heat dissipation because helium has good thermal conductivity; sometimes inert gases such as neon may need to be introduced to adjust the gas pressure in the inner target tube 21 or change the neutron energy spectrum. Through multiple gas inlet holes 241 and multiple gas inlet pipes, the type of gas introduced can be flexibly selected and controlled. At the same time, a specific gas environment can also be accurately created. Different fuel rods 22 may have different requirements for gas composition during irradiation. This embodiment can provide suitable gases according to the position of the fuel rod 22 (for example, the fuel rod 22 in different diameter areas of the inner target tube 21) or the type of the fuel rod 22 (such as the new fuel rod 22 and the traditional fuel rod 22). For example, for some fuel rods 22 that are more sensitive to oxidation, an inert gas can be continuously introduced through an air inlet pipe to prevent oxidation, while a small amount of gas for auxiliary heat dissipation can be introduced through another air inlet pipe, thereby accurately meeting the special requirements of the fuel rod 22 for the gas environment.

[0065] In some possible implementations disclosed in this application, see Figure 3 As shown, the neutron screen assembly 3 includes: an inner sleeve 31, an outer sleeve 32 and a multi-segment neutron screen 33; the inner sleeve 31 is arranged in the outer sleeve 32, and the two ends of the outer sleeve 32 and the inner sleeve 31 are sealed and connected by a cover plate 34, the outer side surface of the inner sleeve 31, the inner side surface of the outer sleeve 32 and the two cover plates 34 constitute a sealed cavity, and the multi-segment neutron screen 33 is arranged in sequence in the sealed cavity along the axial direction.

[0066] In this embodiment, the neutron screen assembly 3 can effectively shield and screen neutrons. The neutron energy spectrum in the thermal spectrum research reactor is different from that in the fast reactor. The neutron screen 33 can block some unnecessary neutrons and allow neutrons that are more consistent with the fast reactor energy spectrum characteristics to pass through, thereby creating a neutron energy spectrum environment that is partially similar to that of the fast reactor for the fuel rod assembly 2 inside. Furthermore, the sealed cavity composed of the outer side surface of the inner sleeve 31, the inner side surface of the outer sleeve 32 and the two cover plates 34 provides a stable installation environment for the neutron screen 33, which can prevent external factors from interfering with the neutron screen 33 and ensure that the performance of the neutron screen 33 is not affected. At the same time, the sealed cavity also helps to control the internal reflection and scattering paths of neutrons, reduce neutron leakage, improve neutron utilization efficiency, and further optimize the neutron energy spectrum adjustment effect.

[0067] The neutron shield assembly 3 may be a nested structure. Specifically, the inner sleeve 31 is located at the innermost layer, the outer sleeve 32 is wrapped outside the inner sleeve 31, forming a double-layer tube structure, and the multi-segment neutron shield 33 is placed in the space between the two layers of tubes.

[0068] The two ends of the outer sleeve 32 and the inner sleeve 31 are sealed and connected by a cover plate 34. The cover plate 34 closes the openings at both ends, so that a relatively independent space is formed between the inner sleeve 31 and the outer sleeve 32. Thus, the internal structural integrity is ensured, and external substances (such as dust, impurities, etc.) are prevented from entering the space between the inner sleeve 31 and the outer sleeve 32, while also preventing the internal gas or neutrons from leaking out.

[0069] Among them, multiple sections of neutron shields 33 are sequentially arranged in the sealed cavity along the axial direction, and the axial direction can be the length direction of the inner sleeve 31 and the outer sleeve 32. In this embodiment, the neutron shield 33 is divided into multiple sections and arranged in sequence, so that the neutrons can be layered and adjusted according to different needs. Each section of the neutron shield 33 can have different materials, thicknesses or structures, so that in the process of neutrons propagating from the outer layer to the internal space where the fuel rod assembly 2 is located, the neutron shields 33 of different sections can absorb, scatter or slow down the neutrons in sequence, so as to more finely adjust the energy spectrum and flux of the neutrons, and finally make the neutron energy spectrum reaching the fuel rod assembly 2 through the neutron shield assembly 3 more in line with the experimental requirements.

[0070] In the above embodiment, the sub-screens 33 in each segment are made of different materials, and the thickness of the sub-screens 33 in each segment is different.

[0071] In this embodiment, each segment of the neutron screen 33 is made of different materials, which enables the neutron screen assembly 3 to screen and adjust neutrons in multiple dimensions. Different materials have different interaction characteristics with neutrons. For example, some materials have a strong moderation effect on fast neutrons, which can reduce the energy of fast neutrons and make them closer to the neutron energy level in the fast reactor; while other materials may have a good absorption effect on neutrons in a specific energy range, which can reduce unnecessary neutron components. By combining these materials with different neutron adjustment characteristics into multiple segments of neutron screens 33, the neutron energy spectrum passing through the neutron screen assembly 3 can be accurately adjusted according to design requirements to make it more consistent with the actual neutron energy spectrum in the fast reactor. At the same time, the different thicknesses of each segment of the neutron screen 33 further enhance the accuracy of the neutron energy spectrum adjustment. Thicker neutron screens 33 can absorb or scatter neutrons more effectively, and are suitable for situations where a large number of neutrons of certain specific energies need to be reduced. Thinner neutron screens 33 may be used to fine-tune the neutron energy spectrum or moderately moderate higher energy neutrons. For example, for a neutron flow with higher energy and larger flux, its flux is first reduced by a thicker neutron shield 33 with absorption function, and then its energy is finely adjusted by a thinner neutron shield 33 made of a moderating material. In this way, high-precision shaping of the neutron energy spectrum can be gradually achieved, making the neutron environment of the fuel rod assembly 2 closer to the fast reactor environment.

[0072] Among them, the neutron shields 33 of different materials are combined together to coordinately adjust the neutrons. For example, a section of the neutron shield 33 may be made of boron, which has a strong absorption capacity for thermal neutrons. When the thermal neutron flow passes through this section of the neutron shield 33, most of the thermal neutrons will be absorbed. Then, the next section of the neutron shield 33 may be made of graphite, which is mainly used to moderate neutrons. In this way, by arranging the neutron shields 33 of different materials in sequence, it is possible to first absorb the unnecessary neutron components, and then perform operations such as slowing down the remaining neutrons, so as to accurately shape the neutron energy spectrum that meets the requirements.

[0073] Among them, the thickness of each section of the neutron screen 33 is different. It can be understood that the thickness directly affects the shielding effect of the neutron screen 33 on neutrons. Thicker neutron screens 33 can provide stronger shielding capabilities. For example, if the main function of a section of the neutron screen 33 is to absorb neutrons in a specific energy range, increasing its thickness can allow more of such neutrons to be absorbed. Just like a thick wall can block light better than a thin wall, a thicker neutron absorption screen can more effectively reduce the number of unnecessary neutrons. At the same time, different thicknesses are also used to fine-tune the energy spectrum and flux of neutrons. The thinner neutron screen 33 has relatively small changes in the neutron energy spectrum, which is suitable for fine-tuning the neutron energy spectrum. For example, after passing through a thicker screen mainly used to absorb neutrons, it may only be necessary to make a small adjustment to the energy of the remaining neutrons, and at this time the thinner moderated neutron screen 33 can play a role.

[0074] In some possible implementations disclosed in this application, see Figure 1 and Figure 4 As shown, the driving assembly 4 includes: a driving part 41, a transmission part 42 and a connecting part 43; the first end of the connecting part 43 is connected to the transmission part 42, the second end of the connecting part 43 is connected to the neutron screen assembly 3, and the transmission part 42 is also connected to the driving part 41. The driving part 41 is used to drive the transmission part 42 to move, so as to drive the neutron screen assembly 3 to rotate circumferentially and / or move axially through the connecting part 43.

[0075] In this embodiment, the driving part 41 drives the neutron shield assembly 3 to rotate circumferentially through the transmission part 42 and the connection part 43, which can change the angle at which neutrons enter the fuel rod assembly 2, thereby changing the neutron flux in the local area and optimizing the irradiation uniformity of each part of the fuel rod 22. At the same time, the driving part 41 can also drive the neutron shield assembly 3 to move axially through the transmission part 42 and the connection part 43 to change the relative position of the fuel rod assembly 2 inside the neutron shield assembly 3, so that the fuel rod assembly 2 is in different neutron environments, providing more satisfactory irradiation conditions for the fuel rod 22. Moreover, the axial movement can also be used to simulate the irradiation conditions of the fuel rod 22 at different positions in the fast reactor, which increases the diversity and practicality of the irradiation test.

[0076] Among them, the connecting part 43 plays the role of a bridge, the first end of the connecting part 43 is connected to the transmission part 42, and the second end of the connecting part 43 is connected to the neutron screen assembly 3. Thus, the movement of the transmission part 42 is transmitted to the neutron screen assembly 3. The transmission part 42 is connected to the driving part 41. The driving part 41 serves as a power source, and the power generated by the driving part 41 passes through the transmission part 42 and the connecting part 43, and finally acts on the neutron screen assembly 3. In actual applications, the connecting part 43 can be directly connected to the neutron screen assembly 3 to transmit the power transmitted from the transmission part 42 to the neutron screen assembly 3, so that the neutron screen assembly 3 can generate circumferential rotation and / or axial movement.

[0077] The driving unit 41 is the power core of the entire driving assembly 4. Specifically, the driving unit 41 can generate power to drive the transmission unit 42 to move. The above power can be a mechanical force, such as the rotational force generated by a motor; or it can be other forms of force, such as hydraulic or pneumatic drive. It is understandable that the power output of the driving unit 41 is controlled according to the experimental requirements, such as by setting parameters such as its rotational speed, direction or axial thrust through a control system.

[0078] Among them, the transmission part 42 is mainly responsible for transmitting the power generated by the driving part 41 to the connecting part 43. The transmission part 42 is like an energy "conveyor belt", ensuring that the power can be effectively transmitted from the driving part 41 to the connecting part 43, and some necessary conversions or adjustments may be made to the power during the transmission process. For example, if the driving part 41 generates high-speed rotating power, and the connecting part 43 requires a lower speed but larger torque power to drive the neutron screen assembly 3 to rotate, the transmission part 42 can perform deceleration and torque increase operations through a gear set and the like. In addition, in addition to transmitting power, the transmission part 42 may also convert the form of motion. For example, the driving part 41 may be a power source for generating circumferential rotational motion, and the neutron screen assembly 3 requires axial linear motion. The transmission part 42 can convert the rotational motion into linear motion through a screw-nut mechanism or a worm gear mechanism, thereby meeting the motion requirements of the neutron screen assembly 3.

[0079] In the above embodiments, see Figure 1 and Figure 4 As shown, the driving part 41 includes a first driving unit 411, and the transmission part 42 includes a first cylindrical gear 421, a second cylindrical gear 422, a guide rod 423 and a guide tube 424; the driving end of the first driving unit 411 is connected to the first cylindrical gear 421, the second cylindrical gear 422 is meshed with the first cylindrical gear 421, and the guide rod 423 is connected to the second cylindrical gear 422; the first driving unit 411 is used to drive the first cylindrical gear 421 to rotate, and then drive the guide rod 423 to rotate with the axis of the second cylindrical gear 422 as the rotation center through the second cylindrical gear 422; at least part of the guide rod 423 can be movably arranged in the guide tube 424, and the guide tube 424 is connected to the connecting part 43, thereby driving the connecting part 43 to rotate synchronously.

[0080] In this embodiment, the first driving unit 411 of the driving part 41 drives the guide rod 423 to rotate through cylindrical gear transmission. This cylindrical gear transmission mode (the first cylindrical gear 421 and the second cylindrical gear 422 are meshed) has high transmission accuracy. The meshing between the teeth of the gears can accurately transmit power and ensure the accuracy of the rotational motion.

[0081] The first drive unit 411 of the drive unit 41 is the power source for the circumferential rotation of the neutron screen assembly 3. The driving end of the first drive unit 411 is connected to the first cylindrical gear 421, that is, the power generated by the first drive unit 411 can directly act on the first cylindrical gear 421 to rotate the first cylindrical gear 421. For example, the first drive unit 411 may be a motor, and the output shaft of the motor is fixed to the first cylindrical gear 421 by a key connection or the like. When the motor is started, the rotation of the motor shaft will drive the first cylindrical gear 421 to rotate synchronously.

[0082] Among them, the second cylindrical gear 422 is meshed with the first cylindrical gear 421. When the first cylindrical gear 421 starts to rotate under the drive of the first driving unit 411, the second cylindrical gear 422 will rotate accordingly due to the interaction between the teeth of the gears. In this embodiment, the guide rod 423 is connected to the second cylindrical gear 422, and the number of teeth of the second cylindrical gear 422 is greater than the number of teeth of the first cylindrical gear 421. When the first driving unit 411 drives the first cylindrical gear 421 to rotate, the power is transmitted to the second cylindrical gear 422 through gear meshing. Since the second cylindrical gear 422 has a large number of teeth, according to the principle of gear transmission, a torque amplification effect will be produced. This means that during the transmission process, the torque output to the guide rod 423 increases. For a load that may have a large moment of inertia such as the neutron screen assembly 3 that needs to be driven, a large torque can ensure its stable rotation and overcome the resistance caused by factors such as friction, air resistance and the weight of the assembly itself. At the same time, the relationship between the gear ratios also makes the rotation speed of the second cylindrical gear 422 lower than that of the first cylindrical gear 421, which helps to achieve more precise angle control.

[0083] Among them, at least two guide rods 423 are provided, and at least two guide rods 423 are evenly arranged along the circumferential direction of the second cylindrical gear 422. When the second cylindrical gear 422 rotates, at least two guide rods 423 can rotate with the axis of the second cylindrical gear 422 as the rotation center. In this embodiment, the guide rod 423 can be fixed to the side of the second cylindrical gear 422 close to the neutron screen assembly 3 by welding or bolt connection, so as to ensure the synchronous movement of the guide rod 423 and the second cylindrical gear 422.

[0084] Each guide rod 423 is correspondingly inserted into a guide tube 424, and the guide tube 424 is relatively fixed to the connecting portion 43. When the guide rod 423 rotates under the drive of the second cylindrical gear 422, it can drive the guide tube 424 to rotate with the axis of the second cylindrical gear 422 as the rotation center.

[0085] The axis of the neutron screen assembly 3, the connection part 43 and the second cylindrical gear 422 coincide. When the guide tube 424 rotates with the axis of the second cylindrical gear 422 as the rotation center, the neutron screen assembly 3 can be driven to rotate circumferentially through the connection part 43, thereby realizing precise control of the circumferential rotation angle of the neutron screen assembly 3.

[0086] Specifically, in this embodiment, the driving part 41 is arranged on the side of the positioning flange 1 away from the neutron screen assembly 3, which provides a stable basis for the realization of the driving function and avoids interference with the surrounding space of the neutron screen assembly 3. The connecting part 43 is arranged on the side of the positioning flange 1 close to the neutron screen assembly 3, so that the connecting part 43 can be easily connected to the neutron screen assembly 3, thereby effectively transmitting the power transmitted from the transmission part 42 to the neutron screen assembly 3 to achieve control of its movement. In this structure, the transmission part 42 is between the driving part 41 and the connecting part 43, playing a key role in connecting the upper and lower parts. It should be noted that the transmission part 42 runs through the positioning flange 1 in space. More specifically, the guide rod 423 in the transmission part 42 passes through the opening in the middle of the positioning flange 1, which ensures the continuity and stability of the power transmission from the driving part 41 to the connecting part 43 via the transmission part 42, so that the entire power transmission path can be smoothly realized, and provides reliable power support for the circumferential rotation and axial movement of the neutron screen assembly 3, thereby ensuring the accuracy and effectiveness of the irradiation device's motion control of the neutron screen assembly 3 during operation, and further ensuring that the irradiation experiment can be carried out according to the expected conditions.

[0087] In the above embodiments, see Figure 1 and Figure 4 As shown, the driving part 41 also includes a second driving unit 412, and the transmission part 42 also includes a bevel gear set 425, a screw shaft 426 and a driven shaft 427; the driving end of the second driving unit 412 is connected to the input end of the bevel gear set 425, and the output end of the bevel gear set 425 is connected to the screw shaft 426, and the screw shaft 426 cooperates with the driven shaft 427 through a pipe thread; the second driving unit 412 is used to drive the bevel gear set 425 to operate, so that the screw shaft 426 drives the driven shaft 427 to move axially, and the driven shaft 427 is connected to the connecting part 43 to drive the connecting part 43 to move axially.

[0088] In this embodiment, the second drive unit 412 drives the screw shaft 426 through the bevel gear set 425, and the bevel gear set 425 can change the direction of power transmission. In this structure, the bevel gear set 425 can convert the power direction output by the second drive unit 412 into a direction suitable for the circumferential rotation of the screw shaft 426, ensuring that the screw shaft 426 can stably rotate in the expected direction, and providing accurate power for the axial movement of the driven shaft 427.

[0089] Among them, the second driving unit 412 of the driving part 41 is a power source for axial movement of the neutron screen assembly 3. The driving end of the second driving unit 412 is connected to the input end of the bevel gear set 425, that is, the power generated by the second driving unit 412 can be directly transmitted to the bevel gear set 425. For example, the second driving unit 412 can be a motor, and the output shaft of the motor is fixed to the input end shaft of the bevel gear set 425 by a coupling or a key connection. When the motor starts and rotates, it will drive the input end of the bevel gear set 425 to rotate synchronously.

[0090] Among them, the bevel gear set 425 plays a role in changing the direction of power transmission in the transmission part 42. Specifically, the bevel gear set 425 can convert the power direction (usually horizontal direction or other directions) output by the second drive unit 412 into a direction suitable for the circumferential rotation of the screw shaft 426. It can be understood that the working principle of the bevel gear set 425 is based on the meshing between the two bevel gears. When the bevel gear at the input end rotates under the drive of the second drive unit 412, the bevel gear at the output end meshing therewith will rotate in a different direction, thereby transmitting power to the screw shaft 426, so that the screw shaft 426 can rotate in the desired circumferential direction.

[0091] The outer surface of the screw shaft 426 has threads, and the driven shaft 427 has matching internal threads (pipe threads). When the screw shaft 426 rotates under the drive of the bevel gear set 425, due to the helix angle of the threads and the friction between the threads, the rotation of the screw shaft 426 is converted into the axial movement of the driven shaft 427, thereby driving the driven shaft 427 to move forward or backward along the axial direction of the screw shaft 426.

[0092] The driven shaft 427 can be connected to the connecting portion 43 by welding, bolt connection or spline connection, so that the axial movement of the driven shaft 427 can be transmitted to the connecting portion 43. It can be understood that the connection portion 43 is a component directly connected to the neutron screen assembly 3, and the change of its motion state will directly affect the position of the neutron screen assembly 3. In practical applications, when the second drive unit 412 drives the bevel gear set 425 to operate, and then the screw shaft 426 drives the driven shaft 427 to move axially, the connecting portion 43 will move axially synchronously under the drive of the driven shaft 427. In this way, the control of the axial position of the neutron screen assembly 3 is achieved, so that the axial position of the neutron screen assembly 3 relative to the fuel rod assembly 2 can be accurately adjusted in the irradiation device, thereby changing the neutron energy spectrum and flux distribution around the fuel rod 22, and meeting different irradiation experiment requirements, such as simulating the irradiation of the fuel rod 22 at different axial positions or optimizing the irradiation uniformity of various parts of the fuel rod 22.

[0093] Specifically, in this embodiment, the output end of the bevel gear set 425, the screw shaft 426, the driven shaft 427 and the connecting portion 43 have the same axis center line, which avoids vibration or swing caused by axis deviation. It should be noted that the above-mentioned coincident axis center line is also the rotation center of the guide rod 423 and the guide tube 424. In actual application, the output end of the bevel gear set 425 passes through the positioning flange 1 through the opening in the middle of the positioning flange 1 and is rotatably connected to the screw shaft 426.

[0094] In the above embodiments, see Figure 1 As shown, the connecting part 43 includes a connecting flange 431 and a connecting pipe 432 . The connecting flange 431 is used to fix the guide tube 424 , the driven shaft 427 and the connecting pipe 432 . One end of the connecting pipe 432 away from the connecting flange 431 is connected to the neutron screen assembly 3 .

[0095] In this embodiment, the connecting flange 431 firmly connects the guide tube 424, the driven shaft 427 and the connecting tube 432 together, so that when the guide tube 424 drives the connecting flange 431 to rotate circumferentially, the driven shaft 427 and the connecting tube 432 can move synchronously therewith, and can effectively transmit the rotational force of the guide tube 424 to the connecting tube 432, thereby driving the neutron screen assembly 3 to rotate circumferentially; at the same time, when the driven shaft 427 moves axially, the connecting flange 431 can also ensure that the connecting tube 432 moves axially therewith, thereby realizing the effective transmission of the two modes of movement.

[0096] Among them, the guide tube 424 and the driven shaft 427 can be fixed to the connecting flange 431 by bolt connection or interference fit; the connecting tube 432 can also be connected to the connecting flange 431 by welding, flange connection or slot connection.

[0097] Specifically, in actual application, when the guide tube 424 rotates, since the guide tube 424 and the connecting flange 431 are fixedly connected, the rotational force of the guide tube 424 is transmitted to the connecting flange 431. At the same time, the axial movement of the driven shaft 427 is also transmitted through the connecting flange 431.

[0098] Among them, one end of the connecting pipe 432 away from the connecting flange 431 is connected to the neutron screen assembly 3, so that the connecting pipe 432 becomes a bridge between the connecting flange 431 and the neutron screen assembly 3, transmitting the movement of the connecting flange 431 to the neutron screen assembly 3.

[0099] Specifically, in terms of circumferential rotation, when the connecting flange 431 rotates driven by the guide tube 424, the connecting tube 432 rotates along with the connecting flange 431, thereby transmitting the rotational motion to the neutron screen assembly 3. In terms of axial movement, when the connecting flange 431 moves axially driven by the driven shaft 427, the connecting tube 432 also moves axially, thereby driving the neutron screen assembly 3 to perform axial displacement.

[0100] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0101] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. An irradiation device, characterized in that: include: A positioning flange (1), wherein the positioning flange (1) is mounted on a top fixed structure of a research reactor; A fuel rod assembly (2), wherein the fuel rod assembly (2) is relatively fixed to the positioning flange (1); a neutron shield (33) assembly (3), wherein the neutron shield assembly (3) is arranged outside the fuel rod assembly (2), an axial hollow channel is arranged inside the neutron shield assembly (3), and the fuel rod assembly (2) is located in the hollow channel; A drive assembly (4), wherein the drive assembly (4) is connected to the neutron shield assembly (3), and the drive assembly (4) is used to drive the neutron shield assembly (3) to rotate circumferentially and / or move axially relative to the fuel rod assembly (2).

2. The irradiation device according to claim 1, characterized in that: The fuel rod assembly (2) comprises: An inner target tube (21) and a plurality of fuel rods (22); An upper cover (23) is provided at one end of the inner target tube (21) close to the positioning flange (1), and an air outlet hole (231) is provided on the upper cover (23), and the air outlet hole (231) is used to connect to the air outlet pipe; and a lower cover (24) is provided at one end of the inner target tube (21) away from the positioning flange (1), and the lower cover (24) is provided with an air inlet hole (241), and the air inlet hole (241) is used to connect to the air inlet pipe; A plurality of fuel rods (22) are arranged in the inner target tube (21), positioning blocks (25) are respectively arranged at both ends of the plurality of fuel rods (22), and a connecting block (26) is arranged between two adjacent fuel rods (22), and a through hole is opened at the center of each of the positioning blocks (25) and the connecting block (26), and the through hole is used for gas to pass through.

3. The irradiation device according to claim 2, characterized in that: The inner target tube (21) is a variable diameter tube, and the inner diameter of the inner target tube (21) changes in a step-like manner along a first direction.

4. The irradiation device according to claim 2, characterized in that: At least two air inlet holes (241) are provided, each of the air inlet holes (241) is connected to an air inlet pipe in a one-to-one correspondence, and different air inlet pipes are used to pass different types of gases.

5. The irradiation device according to claim 1, characterized in that: The neutron screen assembly (3) comprises: An inner sleeve (31), an outer sleeve (32) and a multi-segment neutron shield (33); The inner sleeve (31) is arranged in the outer sleeve (32), and the two ends of the outer sleeve (32) and the inner sleeve (31) are sealed and connected via a cover plate (34). The outer side surface of the inner sleeve (31), the inner side surface of the outer sleeve (32) and the two cover plates (34) constitute a sealed cavity, and the multiple sections of the neutron shield (33) are sequentially arranged in the sealed cavity along the axial direction.

6. The irradiation device according to claim 5, characterized in that: Each section of the neutron shield (33) is made of different materials, and each section of the neutron shield (33) has a different thickness.

7. The irradiation device according to claim 1, characterized in that: The driving assembly (4) comprises: A driving part (41), a transmission part (42) and a connecting part (43); The first end of the connecting portion (43) is connected to the transmission portion (42), the second end of the connecting portion (43) is connected to the neutron screen assembly (3), and the transmission portion (42) is also connected to the driving portion (41). The driving portion (41) is used to drive the transmission portion (42) to move, so as to drive the neutron screen assembly (3) to rotate circumferentially and / or move axially through the connecting portion (43).

8. The irradiation device according to claim 7, characterized in that: The driving part (41) comprises a first driving unit (411), and the transmission part (42) comprises a first cylindrical gear (421), a second cylindrical gear (422), a guide rod (423) and a guide tube (424); The driving end of the first driving unit (411) is connected to the first cylindrical gear (421), the second cylindrical gear (422) is meshed with the first cylindrical gear (421), and the guide rod (423) is connected to the second cylindrical gear (422); The first driving unit (411) is used to drive the first cylindrical gear (421) to rotate, and then drive the guide rod (423) to rotate with the axis of the second cylindrical gear (422) as the rotation center through the second cylindrical gear (422); At least a portion of the guide rod (423) is movably disposed in the guide tube (424), and the guide tube (424) is connected to the connecting portion (43), thereby driving the connecting portion (43) to rotate synchronously.

9. The irradiation device according to claim 8, characterized in that: The driving part (41) further includes a second driving unit (412), and the transmission part (42) further includes a bevel gear set (425), a screw shaft (426) and a driven shaft (427); The driving end of the second driving unit (412) is connected to the input end of the bevel gear set (425), the output end of the bevel gear set (425) is connected to the screw shaft (426), and the screw shaft (426) is matched with the driven shaft (427) through a pipe thread; The second driving unit (412) is used to drive the bevel gear set (425) to operate, so that the screw shaft (426) drives the driven shaft (427) to move axially, and the driven shaft (427) is connected to the connecting portion (43) to drive the connecting portion (43) to move axially.

10. The irradiation device according to claim 9, characterized in that: The connecting portion (43) comprises a connecting flange (431) and a connecting pipe (432), wherein the connecting flange (431) is used to fix the guide pipe (424), the driven shaft (427) and the connecting pipe (432), and one end of the connecting pipe (432) away from the connecting flange (431) is connected to the neutron screen assembly (3).

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