Transfer container for secondary neutron source assembly

Abstract

The utility model discloses a transfer container for the secondary neutron source subassembly, including barrel, cover, bearing subassembly and a plurality of radiating fin, barrel has mouth, bottom and side wall, cover and barrel mouth detachable sealing connection, the bearing subassembly can be put into the barrel cavity of barrel from the mouth of barrel, and the radiating fin is equipped with the bottom and the side wall. Neutron shielding layers are arranged at the bottoms of the cover body and the cylinder body. The heat dissipation fins are fixedly connected with the outer surface of the side wall of the cylinder body, and neutron shielding layers are arranged among the heat dissipation fins in a filling mode. The bearing assembly comprises a cylindrical hanging basket, a square tube located in the hanging basket, a supporting piece located in the hanging basket and used for supporting the square tube, and a simulation assembly box located in the square tube. The simulation assembly box is provided with a first rod hole and a second rod hole which are used for correspondingly inserting a neutron source rod and a choke plug rod of the secondary neutron source assembly. The transfer container provided by the utility model is beneficial to reducing operation equipment in the transfer process of the secondary neutron source assembly and shortening the construction period, and can better ensure the safe transportation of the secondary neutron source assembly.

Description

Technical Field

[0001] The utility model relates to the technical field of nuclear material transportation, in particular to a transport container for a secondary neutron source component. Background Art

[0002] Before the first operation of the reactor or after a long shutdown, there are few neutrons in the core, and the nuclear instruments outside the core cannot detect the neutron injection rate level in the reactor. In order to safely start the reactor, the subcriticality of the reactor must be monitored at all times to avoid accidental supercriticality. Therefore, a neutron source assembly is installed in the reactor.

[0003] Two types of neutron source assemblies are used in the reactor core, namely the primary neutron source assembly and the secondary neutron source assembly. The primary neutron source is only used for the first cycle of the initial core. The secondary neutron source is activated in the first cycle and can provide enough neutrons for the reactor to ensure that the subsequent cycles can replace the primary neutron source for the reactor to be started after refueling. In the case that the primary neutron source assembly is unavailable, the secondary neutron source assembly can also replace the primary neutron source to complete the start-up of the new reactor. The activated secondary neutron source has neutron and gamma radioactivity and a certain amount of decay heat. When the activated secondary neutron source assembly is used to start other nuclear power units, it needs to be safely transported to the target unit.

[0004] At present, there are no finished transport containers for secondary neutron source assemblies. The transportation work is carried out by using dry transport containers for transporting spent fuel. However, during the transportation of secondary neutron source assemblies, the loading before transportation and the unloading after transportation are completed in water. The dry transportation scheme requires drainage and vacuuming operations after the secondary neutron source assembly is loaded into the container. According to the current operation plan, the cladding of the secondary neutron source assembly will undergo hot and cold cycles and environmental changes after drying and re-entering the water, which will have an adverse effect on the performance and life of the cladding. In addition, the drying operation requires a lot of equipment to ensure and takes a certain period of time. At the same time, due to the thermal conductivity of the gas, the heat transfer effect of dry transportation is relatively poor, and the safety of the secondary source assembly cladding is threatened to a certain extent. Utility Model Content

[0005] In view of this, an object of the present utility model is to provide a transport container for a secondary neutron source assembly, which is conducive to reducing the operating equipment and shortening the construction period during the transportation of the secondary neutron source assembly, and better ensuring the safe transportation of the secondary neutron source assembly.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] A transport container for a secondary neutron source assembly, comprising:

[0008] A cylinder, the cylinder having a mouth, a bottom and a side wall, the bottom being provided with a neutron shielding layer;

[0009] A cover body, which is detachably sealed and connected to the mouth of the cylinder, and the cover body is provided with a neutron shielding layer;

[0010] A plurality of heat dissipation fins are fixedly connected to the outer surface of the side wall of the cylinder, and a neutron shielding layer is filled between the heat dissipation fins;

[0011] A load-bearing assembly, which can be loaded into the barrel cavity of the barrel through the mouth of the barrel, and the load-bearing assembly includes a cylindrical hanging basket, a square tube located in the hanging basket, a support member located in the hanging basket for supporting the square tube, and a simulation component box located in the square tube; the cross-sectional profile of the hanging basket is consistent with the cross-sectional profile of the barrel cavity of the barrel, and the simulation component box has a first rod hole and a second rod hole for correspondingly inserting the neutron source rod and the baffle rod of the secondary neutron source assembly.

[0012] Optionally, in the above-mentioned transfer container, the heat dissipation fins are evenly distributed along the axial direction of the cylinder, or the heat dissipation fins are evenly distributed along the circumferential direction of the cylinder.

[0013] Optionally, in the above-mentioned transport container, the heat dissipation fins are welded to the outer surface of the side wall of the cylinder, or the heat dissipation fins and the cylinder are an integrated structure.

[0014] Optionally, in the above-mentioned transfer container, the outer diameter of the hanging basket is 1mm~4mm smaller than the inner diameter of the side wall of the cylinder, and / or the cross-sectional dimension of the simulation component box is 1mm~4mm smaller than the cross-sectional dimension of the lumen of the square tube.

[0015] Optionally, in the above-mentioned transport container, the tube wall of the square tube is provided with a plurality of first through holes, the simulation component box is provided with a plurality of second through holes, and the extension direction of the second through holes and the extension direction of the second rod holes meet a vertical condition.

[0016] Optionally, in the above-mentioned transport container, the carrying component includes a plurality of the simulated component boxes and a plurality of the square tubes corresponding to the simulated component boxes one by one, and the simulated component boxes all have the same specifications, or partially have the same specifications, or have different specifications.

[0017] Optionally, in the above-mentioned transfer container, the support member includes a plurality of support plates distributed along the axial direction of the hanging basket, the support plates are provided with mounting holes for the square tubes to pass through, and the outer edges of the support plates are fixedly connected to the inner walls of the hanging basket.

[0018] Optionally, in the above-mentioned transfer container, the support plate is provided with a third through hole for cooling water to pass through.

[0019] Optionally, the above-mentioned transport container further comprises:

[0020] A shell is sleeved on the outside of the cylinder, the shell corresponds to the side wall of the cylinder, and the side of the heat dissipation fin away from the cylinder is connected to the inner surface of the shell;

[0021] The inner shell is lined on the inner wall of the cylinder cavity of the cylinder.

[0022] Optionally, in the above-mentioned transfer container, the material of the cylinder is carbon steel, the materials of the heat dissipation fins, the outer shell and the inner shell are all stainless steel, the distance between the inner surface of the outer shell and the outer surface of the side wall of the cylinder is 300mm~400mm, and the thickness of the side wall of the cylinder is 150mm~300mm.

[0023] The transfer container provided by the utility model can realize wet transportation, that is, the secondary neutron source assembly is in a water environment throughout the entire process of transportation, thereby avoiding the influence of the secondary neutron source assembly's cladding experiencing hot and cold cycles and environmental changes during drainage, vacuum drying and helium backfilling during dry transportation. Compared with dry transportation, the operating equipment in the secondary neutron source assembly transportation process is reduced and the construction period is shortened. At the same time, thanks to the good heat transfer performance of water, the secondary neutron source assembly can be kept in a lower temperature state during transportation, thereby improving the safety of transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0025] Figure 1 It is a longitudinal cross-sectional schematic diagram of a transport container for a secondary neutron source assembly provided by an embodiment of the utility model;

[0026] Figure 2 yes Figure 1 The schematic diagram of the structure shown is after the bearing assembly 4 is removed;

[0027] Figure 3 is a schematic cross-sectional view of the load-bearing component;

[0028] Figure 4 yes Figure 3 The three-dimensional schematic diagram of the load-bearing assembly after removing the hanging basket 41 is shown;

[0029] Figure 5is a schematic diagram of the end face of the simulated component box;

[0030] Figure 6 is a schematic diagram of the secondary neutron source assembly and hold-down system.

[0031] The markings in the figure are:

[0032] 1. Cylinder; 11. Cylinder cavity; 2. Cover; 3. Neutron shielding layer; 4. Load-bearing assembly; 5. Heat sink fins; 6. Outer shell; 7. Inner shell; 8. Gas; 9. Cooling water; P, liquid level;

[0033] 41. hanging basket; 42. square tube; 421. upper through hole; 422. lower through hole; 43. support plate; 431. third through hole; 44. simulation component box; 441. first rod hole; 442. second rod hole; 443. spoke plate; 444. cavity;

[0034] 100. Clamping system; 201. choke rod; 202. neutron source rod. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0036] See also Figure 1 to Figure 6 The embodiment of the utility model provides a transport container for a secondary neutron source assembly, including a cylinder 1, a cover 2, a bearing assembly 4 and a plurality of heat dissipation fins 5, wherein the cylinder 1 has a mouth, a bottom and a side wall, the mouth is opposite to the bottom and is located at both ends of the cylinder 1, and the side wall is the portion between the mouth and the bottom. The cover 2 is detachably sealed and connected to the mouth of the cylinder 1, and after the cover 2 is removed, the mouth of the cylinder 1 is opened. The bearing assembly 4 can be loaded into the barrel cavity 11 of the barrel 1 through the mouth of the cylinder 1, that is, after the mouth is opened, the bearing assembly 4 enters the barrel cavity 11 through the mouth. The heat dissipation fins 5 are fixedly connected to the outer surface of the side wall of the cylinder 1, and a neutron shielding layer 3 is filled and arranged between the heat dissipation fins 5. In addition, the bottom of the cover 2 and the cylinder 1 are also provided with a neutron shielding layer 3.

[0037] The bearing assembly 4 includes a cylindrical hanging basket 41, a square tube 42 located in the hanging basket 41, a support member located in the hanging basket 41 for supporting the square tube 42, and a simulation assembly box 44 located in the square tube 42. The cross-sectional profile of the hanging basket 41 is consistent with the cross-sectional profile of the barrel cavity 11 of the barrel body 1, and the simulation assembly box 44 has a first rod hole 441 and a second rod hole 442 for correspondingly inserting the neutron source rod 202 and the choke rod 201 of the secondary neutron source assembly. It is easy to understand that the first rod hole 441 and the second rod hole 442 of the simulation component box 44 are set according to the size and position of the guide tube matching the secondary neutron source assembly in the reactor fuel assembly. When the secondary neutron source assembly is installed in the core, the neutron source rod 202 and the choke rod 201 of the secondary neutron source assembly are inserted into the guide tube of the fuel assembly. When the secondary neutron source assembly is transported, the neutron source rod 202 and the choke rod 201 of the secondary neutron source assembly are inserted into the first rod hole 441 and the second rod hole 442 of the simulation component box 44. It should be noted that Figure 5 The end face of the simulated component box 44 is shown. The axial dimensions of the simulated component box 44 in the rod hole are similar to those of the simulated component box 44. Figure 4 The lengths of the square tubes 42 are roughly equal. During the transportation of the secondary neutron source assembly, the simulation assembly box 44 is installed in the square tube 42, that is, the lumen of the square tube 42 serves as a positioning groove to carry and position the simulation assembly box 44. Figure 5 As shown, in this embodiment, the simulation component box 44 is provided with four first rod holes 441 and sixteen second rod holes 442. The simulation component box 44 includes a plurality of radially distributed spokes 443, the spokes 443 connecting the central portion and the outer frame portion of the simulation component box 44, and a cavity 444 is formed between the spokes 443 for cooling water 9 to flow through.

[0038] like Figure 1 and Figure 3As shown, when transporting the secondary neutron source assembly, the bearing assembly 4 is in the enclosed space formed by the cover body 2 and the cylinder body 1. In addition to the bearing assembly 4, the enclosed space is also equipped with a certain amount of cooling water 9. The amount of cooling water 9 should meet the requirement that the liquid level P is higher than the position of the square tube 42 when the cylinder body 1 is in a horizontal transportation state. Preferably, about 20% of the volume in the hanging basket 41 is reserved for the gas 8. This reserved volume can well meet the volume expansion and evaporation of the cooling water 9 due to heat. The transport container provided by the utility model can realize wet transportation, that is, the secondary neutron source assembly is in a water environment throughout the transportation process, thereby avoiding the influence of the cold and hot cycle and environmental changes of the secondary neutron source assembly during the drainage, vacuum drying and helium backfilling during the dry transportation process. Compared with the dry transportation, the operating equipment in the transportation process of the secondary neutron source assembly is reduced and the construction period is shortened. At the same time, thanks to the good heat transfer performance of water, the secondary neutron source assembly can be ensured to be in a lower temperature state during the transportation process, thereby improving the safety of transportation.

[0039] In specific practical applications, there are many options for arranging the heat dissipation fins 5 on the cylinder 1. The heat dissipation fins 5 can be distributed along the axial direction of the cylinder 1 or along the circumference of the cylinder 1. The heat dissipation fins 5 can be set to be flat or corrugated. It is easy to understand that in order to obtain a good heat dissipation effect, the heat dissipation fins 5 are preferably arranged to be evenly distributed, that is, the heat dissipation fins 5 are arranged on the cylinder 1 at equal intervals. Figure 1 As shown, in this embodiment, the heat dissipation fins 5 are configured in the shape of an annular gasket and are evenly distributed along the axial direction of the cylinder 1, and the space between adjacent heat dissipation fins 5 is filled with the neutron shielding layer 3. In order to achieve a fixed connection between the heat dissipation fins 5 and the cylinder 1, the heat dissipation fins 5 can be configured to be welded to the outer surface of the side wall of the cylinder 1. Of course, the heat dissipation fins 5 can also be configured as an integral structure with the cylinder 1, that is, the heat dissipation fins 5 and the cylinder 1 are integrally formed, which can also achieve the effect of a fixed connection between the heat dissipation fins 5 and the cylinder 1.

[0040] like Figure 1 and Figure 3 As shown, in specific practical applications, the outer diameter of the hanging basket 41 should be slightly smaller than the inner diameter of the side wall of the cylinder 1, so as to facilitate installation and reserve space for thermal expansion. Specifically, the outer diameter of the hanging basket 41 can be set to be 1mm~4mm smaller than the inner diameter of the side wall of the cylinder 1, such as 2mm, 3mm. Similarly, the cross-sectional dimension of the simulation component box 44 should be slightly smaller than the cross-sectional dimension of the lumen of the square tube 42. Specifically, the cross-sectional dimension of the simulation component box 44 can be set to be 1mm~4mm smaller than the cross-sectional dimension of the lumen of the square tube 42, such as 2mm.

[0041] In a preferred embodiment, the wall of the square tube 42 is provided with a plurality of first through holes, and the simulation component box 44 is provided with a plurality of second through holes (not shown in the figure), and the extension direction of the second through holes is perpendicular to the extension direction of the second rod hole 442. The extension direction of the second rod hole 442 is the axial direction of the second rod hole 442, so the extension direction of the second through hole is parallel to the end face of the simulation component box 44. The first through holes and the second through holes are used for cooling water 9 to pass through, so that the cooling water 9 forms a circulation flow in the hanging basket 41. See Figure 3 and Figure 4 In this embodiment, the first through hole includes an upper through hole 421 opened on the top wall of the square tube 42 and a lower through hole 422 opened on the bottom wall of the square tube 42. It should be noted that the top wall of the square tube 42 refers to the bearing assembly 4 in Figure 3 The upper part of the square tube 42 in the transport state shown, the bottom wall of the square tube 42 is the part opposite to the top wall. Inside the container, the heat generated by the decay heat of the secondary neutron source assembly causes the cooling water 9 to increase in temperature and decrease in density, thereby moving upward under the action of buoyancy and entering the upper space through the upper through hole 421. Then, the cooling water 9 near the inner wall of the hanging basket 41 moves downward under the action of gravity after being cooled by the inner wall of the hanging basket 41, and finally enters the simulation component box 44 through the lower through hole 422 and the second through hole on the simulation component box 44, thereby completing the circulation of the cooling water 9 and enhancing the heat transfer effect. The cooling water 9 transfers the heat to the hanging basket 41 and then conducts it to the external environment.

[0042] In the process of transporting the secondary neutron source assembly by the transport container of the utility model, the heat released by the secondary neutron source assembly is transferred to the external environment by the transport container through passive natural heat dissipation, and no forced cooling is used. Specifically, the decay heat of the secondary neutron source assembly is first transferred to the hanging basket 41 by conduction, convection, etc., and the hanging basket 41 is then transferred to the cylinder 1 by conduction and radiation. The cylinder 1 transfers the heat to the neutron shielding layer 3 of the side wall part and the heat dissipation fins 5 between the neutron shielding layer 3 by heat conduction, and finally transfers the heat to the surrounding atmosphere by convection and radiation.

[0043] like Figure 3 and Figure 4As shown, in a preferred embodiment, the bearing assembly 4 includes a plurality of simulation assembly boxes 44 and a plurality of square tubes 42 corresponding to the simulation assembly boxes 44 one by one, for example, the number of square tubes 42 is set to three, four or five. Since the simulation assembly boxes 44 correspond to the square tubes 42 one by one, the number of simulation assembly boxes 44 and the number of square tubes 42 are the same. Specifically, these simulation assembly boxes 44 can be set to have the same specifications in all aspects, that is, the structures and sizes of any two simulation assembly boxes 44 are completely consistent, or they can be set to have the same specifications in some aspects, that is, the structures and / or sizes of at least two simulation assembly boxes 44 are inconsistent, or they can be set to have different specifications, that is, no two simulation assembly boxes 44 have different specifications.

[0044] There are many options for the structural form of the support, such as Figure 3 and Figure 4 As shown, in a preferred embodiment, the support member includes a plurality of support plates 43 distributed along the axial direction of the hanging basket 41, the support plate 43 is provided with a mounting hole for the square tube 42 to pass through, and the outer edge of the support plate 43 is fixedly connected to the inner wall of the hanging basket 41. Further preferably, the support plate 43 is provided with a third through hole 431 for the cooling water 9 to pass through. In other embodiments, the support member can also be configured as a rod, for example, the square tube 42 is fixedly connected to the inner wall of the hanging basket 41 through a plurality of support rods.

[0045] like Figure 1 and Figure 2 As shown, in a preferred embodiment, the transport container further includes an outer shell 6 and an inner shell 7, wherein the inner shell 7 is lined on the inner wall of the barrel cavity 11 of the cylinder 1, that is, the inner shell 7 is in contact with the inner wall of the barrel cavity 11 of the cylinder 1. The outer shell 6 is sleeved on the outside of the cylinder 1, and the outer shell 6 corresponds to the side wall position of the cylinder 1, and the side of the heat dissipation fin 5 away from the cylinder 1 is connected to the inner surface of the outer shell 6. It should be noted that in this structure, since the inner shell 7 is in contact with the inner wall of the barrel cavity 11 of the cylinder 1, the cavity of the inner shell 7 is regarded as the barrel cavity 11 of the cylinder 1, which does not affect the understanding of the technical solution of the utility model. After the decay heat of the secondary neutron source assembly is transferred to the hanging basket 41 by conduction, convection, etc., the hanging basket 41 is then transferred to the inner shell 7 by conduction and radiation. Starting from the inner shell 7, the heat is successively transferred to the cylinder 1, the neutron shielding layer 3 and the heat dissipation fins 5 of the side wall of the cylinder 1, and the outer shell 6 by heat conduction. The housing 6 transfers heat to the surrounding atmosphere by convection and radiation.

[0046] like Figure 1 and Figure 6As shown, in a preferred embodiment, the axial dimension of the bearing assembly 4 in the cylinder 1 satisfies that after the bearing assembly 4 is loaded into the cylinder cavity 11, a suitable space can be reserved for the clamping system 100 of the secondary neutron source assembly. When the cover 2 is closed, the cover 2 abuts against the clamping system 100, thereby making the bearing assembly 4 more stable in the cylinder 1. In specific practical applications, the material of the cylinder 1 can be carbon steel, and the thickness of the side wall of the cylinder 1 should meet the requirements of shielding gamma rays, preferably set to 150mm~300mm, for example, 200mm. The material of the heat sink fins 5, the outer shell 6 and the inner shell 7 can be stainless steel, and the distance between the inner surface of the outer shell 6 and the outer surface of the side wall of the cylinder 1 is preferably set to 300mm~400mm, for example, 350mm. The thickness of the outer shell 6 and the inner shell 7 is preferably set to 5mm~15mm, for example, 10mm. The thickness of the heat sink fins 5 is preferably set to 5 mm to 10 mm, for example 8 mm. In order to enhance the heat exchange efficiency, a copper sheet may be laid on one or both sides of the heat sink fins 5 , for example, the copper sheet is welded to the heat sink fins 5 .

[0047] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0048] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A transport container for a secondary neutron source assembly, characterized in that: include: A cylinder, the cylinder having a mouth, a bottom and a side wall, the bottom being provided with a neutron shielding layer; A cover body, which is detachably sealed and connected to the mouth of the cylinder, and the cover body is provided with a neutron shielding layer; A plurality of heat dissipation fins are fixedly connected to the outer surface of the side wall of the cylinder, and a neutron shielding layer is filled between the heat dissipation fins; A load-bearing assembly, which can be loaded into the barrel cavity of the barrel through the mouth of the barrel, and the load-bearing assembly includes a cylindrical hanging basket, a square tube located in the hanging basket, a support member located in the hanging basket for supporting the square tube, and a simulation component box located in the square tube; the cross-sectional profile of the hanging basket is consistent with the cross-sectional profile of the barrel cavity of the barrel, and the simulation component box has a first rod hole and a second rod hole for correspondingly inserting the neutron source rod and the baffle rod of the secondary neutron source assembly.

2. The transport container according to claim 1, characterized in that: The heat dissipation fins are evenly distributed along the axial direction of the cylinder, or the heat dissipation fins are evenly distributed along the circumferential direction of the cylinder.

3. The transport container according to claim 1, characterized in that: The heat dissipation fins are connected to the outer surface of the side wall of the cylinder by welding, or the heat dissipation fins and the cylinder are an integrated structure.

4. The transport container according to claim 1, characterized in that: The outer diameter of the hanging basket is 1 mm to 4 mm smaller than the inner diameter of the side wall of the cylinder, and / or the cross-sectional dimension of the simulation component box is 1 mm to 4 mm smaller than the cross-sectional dimension of the lumen of the square tube.

5. The transport container according to claim 1, characterized in that: The tube wall of the square tube is provided with a plurality of first through holes, the simulation component box is provided with a plurality of second through holes, and the extension direction of the second through holes and the extension direction of the second rod holes meet a vertical condition.

6. The transport container according to claim 1, characterized in that: The bearing component includes a plurality of the simulation component boxes and a plurality of the square tubes corresponding to the simulation component boxes one by one. The simulation component boxes all have the same specifications, or partially have the same specifications, or have different specifications.

7. The transport container according to claim 1, characterized in that: The support member comprises a plurality of support plates distributed along the axial direction of the hanging basket, the support plates are provided with mounting holes for the square tubes to pass through, and the outer edges of the support plates are fixedly connected to the inner walls of the hanging basket.

8. The transport container according to claim 7, characterized in that: The support plate is provided with a third through hole for cooling water to pass through.

9. The transport container according to any one of claims 1 to 8, characterized in that: Also includes: An outer shell is sleeved on the outside of the cylinder, the outer shell corresponds to the side wall of the cylinder, and the side of the heat dissipation fin away from the cylinder is connected to the inner surface of the outer shell; The inner shell is lined on the inner wall of the cylinder cavity of the cylinder.

10. The transport container according to claim 9, characterized in that: The material of the cylinder is carbon steel, the materials of the heat dissipation fins, the outer shell and the inner shell are all stainless steel, the distance between the inner surface of the outer shell and the outer surface of the side wall of the cylinder is 300mm~400mm, and the thickness of the side wall of the cylinder is 150mm~300mm.

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