Cylinder body manufacturing method of nuclear power station pressure vessel shielding top cover and cylinder body structure

Abstract

The invention discloses a barrel body manufacturing method and a barrel body structure of a nuclear power station pressure vessel shielding top cover, the barrel body manufacturing method comprises the following steps: S100, multiple layers of lead plates are sequentially laid at the same position of an inner barrel body in the radial direction, the adjacent stacked lead plates are tightly attached, and the axial edges of the multiple layers of lead plates are sequentially arranged in a staggered mode from inside to outside; s200, lead water is cast to fill the gap, and a lead water layer is formed after the lead water is solidified; s300, first heat insulation layers are laid on the outer side face of the first end and the outer side face of the second end of the lead plate on the outermost layer correspondingly; s400, an inner-layer fixing plate is laid on the outermost-layer lead plate and tightly attached to the outermost-layer lead plate, and the two ends of the inner-layer fixing plate are fixedly welded to the upper flange face and the lower flange face correspondingly; and S500, the steps S100-S400 are repeated for multiple times in the circumferential direction of the inner barrel, and finally a plurality of barrel-shaped lead plate layers and barrel-shaped inner layer fixed barrels are formed. According to the barrel manufacturing method, the conditions of deviation, dislocation, wrinkles, bumps and the like in the binding process of the lead plate are reduced, and the binding precision of the lead plate is improved.

Description

Technical Field

[0001] The invention relates to the technical field of manufacturing false top covers of nuclear power plant pressure vessels, and in particular to a cylinder manufacturing method and a cylinder structure of a shielding top cover of a nuclear power plant pressure vessel. Background Art

[0002] During the overhaul of nuclear power plant reactor refueling, after the reactor pressure vessel is opened, a large amount of radioactive materials in the core will leak out. When the water level of the reactor pool is high, it can be isolated and absorbed by the boric acid water in the pool. But when the water level is low, it is necessary to use a false top cover to shield the reactor pressure vessel after opening, so as to isolate and shield the radioactive materials to a certain extent. The false top cover uses lead plate as a shielding layer.

[0003] Lead plates are soft at room temperature, have high density and good tensile properties. Therefore, under gravity, high-purity lead plates are prone to flow. When using lead plates to wrap the outer cylinder of a large container, the flow can easily cause uneven arrangement of the lead plates on the entire circumference, with some areas experiencing deviation, dislocation, wrinkles or bulging.

[0004] At present, the manufacturing of pressure vessels wrapped with multi-layer lead plates is common in equipment that requires radiation protection or special anti-corrosion requirements. The existing general process is mainly: determine the size of the lead plate → fix the single-layer lead plate → wrap multiple layers → finish the details. This lead wrapping process is used for lead plate coating on the surface of small containers, and the total effective thickness of the lead plate is generally ≤5mm. It is not suitable for the wrapping and manufacturing of "embedded" lead plates with a thickness of more than 10mm on the surface of large heavy-loaded containers with a diameter of more than 3m. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for manufacturing a cylinder body of a shielding top cover of a nuclear power plant pressure vessel and a cylinder body structure.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a method for manufacturing a cylinder of a shielding top cover of a nuclear power plant pressure vessel, comprising the following steps:

[0007] S000: Connect and fix the inner cylinder to the upper flange surface and the lower flange surface respectively;

[0008] S100: laying multiple layers of lead plates in sequence along the radial direction at the same position of the inner cylinder, with the adjacent stacked lead plates tightly fitted, and the axial edges of the multiple layers of lead plates being staggered in sequence from the inside to the outside;

[0009] Wherein, the inner cylinder is placed horizontally, the first end of the lead plate is in contact with the lower flange surface, and a gap is left between the second end of the lead plate and the upper flange surface;

[0010] S200: pouring molten lead to fill the gap between the second end of the lead plate and the upper flange surface, and waiting for the molten lead to solidify to form a molten lead layer;

[0011] S300: laying a first heat insulation layer on the outer side surface of the first end and the outer side surface of the second end of the outermost lead plate respectively;

[0012] S400: Laying the inner fixing plate on the outermost lead plate and closely fitting it with the outermost lead plate, the axial edge of the outermost lead plate is staggered with the axial edge of the inner fixing plate, and the two ends of the inner fixing plate are respectively welded and fixed to the upper flange surface and the lower flange surface;

[0013] S500: repeating steps S100 to S400 several times along the circumference of the inner cylinder to finally form a plurality of cylindrical lead plate layers and a cylindrical inner fixed cylinder;

[0014] S600: laying a plurality of outer fixed cylinders outside the inner fixed cylinder.

[0015] In some embodiments, step S500 further includes laying a second heat insulation layer at a specific position outside the outermost lead plate, and welding and fixing adjacent inner layer fixing plates in sequence along the circumference of the inner cylinder;

[0016] The specific position is a position opposite to an axial edge of the inner layer fixing plate.

[0017] In some embodiments, one of the lead plates is 1 / 4 of the total laid cylinder volume of the lead plate layer, and one of the inner layer fixed plates is 1 / 4 of the total laid cylinder volume of the layer;

[0018] In step S500, steps S100 to S400 are repeated three times along the circumference of the inner cylinder.

[0019] In some embodiments, in step S600, the number of the outer layer fixed cylinders is at least two, each layer of the outer layer fixed cylinders comprises the same number of outer layer fixed plates (61) as the number of the inner layer fixed plates, and the axial edges of the inner layer fixed plates and the axial edges of at least two layers of the outer layer fixed plates (61) are sequentially staggered from the inside to the outside;

[0020] Two adjacent outer layer fixing plates (61) on the same layer of the outer layer fixing cylinder are fixed by welding.

[0021] In some embodiments, step S000 further includes polishing the surface of the inner cylinder so that the pit depth of the outer surface of the inner cylinder is less than or equal to 0.25 mm and the scratch depth is less than or equal to 0.2 mm.

[0022] In some embodiments, in step S400, the inner fixing plate and the lead plate are tightly clamped by a clamp so that the inner fixing plate and the outermost lead plate are tightly fitted;

[0023] After welding and fixing, grinding the welds between the inner fixing plate and the upper flange surface and the lower flange surface so that the welds are flush with the surface of the inner fixing plate;

[0024] After ensuring that the lead plate is compacted, remove the clamp.

[0025] In some embodiments, the axial edges of the multiple layers of lead plates are offset by a distance greater than or equal to 50 mm; the axial edge of the outermost layer of lead plate is offset by a distance greater than or equal to 50 mm from the axial edge of the inner fixed plate.

[0026] In some embodiments, the length of the first thermal insulation layer is greater than the arc length of the lead plate, and the width of the first thermal insulation layer is greater than or equal to 100 mm;

[0027] The length of the second thermal insulation layer is greater than the axial height of the lead plate, and the width of the second thermal insulation layer is greater than or equal to 100 mm.

[0028] In some embodiments, the number of lead sheet layers is four.

[0029] The present invention also constructs a cylinder structure manufactured by any of the cylinder manufacturing methods described above, comprising an inner cylinder, an upper flange surface, a lower flange surface, a plurality of lead plate layers, an inner fixed cylinder and a plurality of outer fixed cylinders, wherein the inner cylinder is respectively connected and fixed to the upper flange surface and the lower flange surface; a plurality of lead plate layers are sleeved on the outer circumference of the inner cylinder and are respectively connected and fixed to the upper flange surface and the lower flange surface; the inner fixed cylinder is sleeved on the outer circumference of the outermost lead plate layer and is respectively connected and fixed to the upper flange surface and the lower flange surface; a plurality of outer fixed cylinders are sleeved on the inner fixed cylinder and are respectively connected and fixed to the upper flange surface and the lower flange surface;

[0030] Each of the lead plate layers includes a plurality of lead plates. Adjacent lead plates in the same lead plate layer have gaps between them and are connected and fixed by lead water. Adjacent stacked lead plates fit tightly together, and axial edges of the multiple layers of lead plates are staggered in sequence from the inside to the outside.

[0031] By implementing the present invention, the following beneficial effects are achieved:

[0032] The method for manufacturing the cylinder of the shielding top cover of the pressure vessel of a nuclear power plant of the present invention can effectively make the ground lead plate fit and wrap around the outer surface of the inner cylinder by laying multiple layers of lead plates and inner fixed plates in sequence in the radial direction at the same position. The gap between the second end and the upper flange surface is filled by pouring lead water, and the axial edges of the multiple layers of lead plates are sequentially staggered from the inside to the outside, and the axial edges of the lead plates are staggered with the axial edges of the inner fixed plates, so as to improve the uniformity of the lead plate thickness on the circumference of the inner cylinder, reduce the deviation, dislocation, wrinkles, bulging, etc. in the process of lead plate wrapping, reduce the difficulty of manufacturing and construction, improve the wrapping accuracy of the lead plate, and effectively reduce the fluidity of the lead plate.

[0033] The cylinder structure of the present invention manufactured by the cylinder manufacturing method described in any of the above items can fit tightly between the inner cylinder and the lead plate layer, adjacent lead plate layers, the lead plate layer and the lead inner fixed cylinder, the inner fixed cylinder and the outer fixed cylinder, and the adjacent outer fixed cylinder. The axial edges of the multiple layers of lead plates are staggered, and the gaps between adjacent lead plates of the same layer are filled by pouring lead water to achieve splicing of each lead plate layer, thereby improving the uniformity of the lead plates, effectively ensuring the shielding effect of the lead plates, and preventing dislocation during long-term use. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0035] Figure 1 It is a flow chart of a method for manufacturing a cylinder of a shielding top cover of a nuclear power plant pressure vessel according to an embodiment of the present invention;

[0036] Figure 2 is based on Figure 1 An overall schematic diagram of a cylinder of an embodiment manufactured by a cylinder manufacturing method;

[0037] Figure 3 yes Figure 2 Installation details of the middle inner cylinder and the upper and lower flange surfaces;

[0038] Figure 4 is Figure 3 A detailed diagram of the structure of a multi-layer lead plate wrapped on a position of the inner cylinder;

[0039] Figure 5 is Figure 4 Structural details of the inner layer fixing plate being wrapped continuously at the same position of the inner cylinder;

[0040] Figure 6 yes Figure 5 The enlarged structural diagram of the structure I in the middle is specifically a schematic diagram of the installation of the heat insulation layer on the bottom outer side of the outermost lead plate;

[0041] Figure 7 yes Figure 5A schematic diagram of the actual effect of the first wrapping of the multi-layer lead plate and the inner fixed plate; wherein the upper flange surface and the lower flange surface are not shown;

[0042] Figure 8 is Figure 7 Schematic diagram of the structure of continuing the second bandage on the basis;

[0043] Fig. 9 yes Figure 7 The enlarged structural diagram of the middle H structure is specifically a schematic diagram of the installation of the thermal insulation layer outside the lead plate at the gap position of the adjacent inner fixed plate;

[0044] Fig.10 is Figure 8 The schematic diagram of the structure of the third bandage on this basis;

[0045] Fig.11 is Fig.10 The structural diagram of the fourth bandage is continued on this basis;

[0046] Fig.12 is Fig.11 The structural details of the outer fixed plate are still wrapped on the foundation. DETAILED DESCRIPTION

[0047] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0048] It should be noted that the flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor do they have to be executed in the order described. For example, some operations / steps can be decomposed, while some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0049] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0050] In the description of the invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0051] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 a chemical connection; it can be a direct connection or 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 the present invention can be understood by specific circumstances.

[0052] See also Figure 1 and Figure 2 One embodiment of the present invention discloses a method for manufacturing a cylinder of a shielding top cover of a nuclear power plant pressure vessel and a cylinder manufactured according to the cylinder manufacturing method. The cylinder includes an inner cylinder 1, an upper flange surface 2, a lower flange surface 3, a plurality of lead sheet layers 4, an inner fixed cylinder 5 and a plurality of outer fixed cylinders 6. The inner cylinder 1 is connected and fixed to the upper flange surface 2 and the lower flange surface 3, respectively. The plurality of lead sheet layers 4 are sleeved on the outer periphery of the inner cylinder 1 and are connected and fixed to the upper flange surface 2 and the lower flange surface 3, respectively. The inner fixed cylinder 5 is sleeved on the outer periphery of the outermost lead sheet layer 4 and is connected and fixed to the upper flange surface 2 and the lower flange surface 3, respectively. A plurality of outer fixed cylinders 6 are sleeved on the inner fixed cylinder 5 and are connected and fixed to the upper flange surface 2 and the lower flange surface 3, respectively.

[0053] Each lead sheet layer 4 includes a plurality of lead sheets 41. A gap is left between adjacent lead sheets 41 of the same lead sheet layer 4 and they are connected and fixed by lead water. Adjacent stacked lead sheets 41 fit tightly together, and the axial edges of the multiple layers of lead sheets 41 are sequentially staggered from the inside to the outside. It can be understood that the multiple lead sheets 41 of each lead sheet layer 4 can be lead sheets 41 with the same arc length or lead sheets with different arc lengths.

[0054] The barrel manufacturing method comprises the following steps:

[0055] See also Figure 3 , perform preparations before wrapping, i.e. step S000: connect and fix the inner cylinder 1 to the upper flange surface 2 and the lower flange surface 3 respectively. The inner cylinder 1 is welded and fixed to the upper flange surface 2 and the lower flange surface 3 respectively, and the welds between the inner cylinder 1 and the inner and outer surfaces of the upper flange surface 2 and the lower flange should be polished flush with the parent material. Among them, the upper flange surface 2 is stepped. Multiple steps expand outward from the inner cylinder 1, and the distance between the outer step and the lower flange is greater than the distance between the adjacent inner step and the lower flange. Preferably, the upper flange surface 2 is provided with at least three steps, which are used to install multiple lead sheet layers 4, inner fixed cylinder 5 and outer fixed cylinder 6 in sequence from the inner cylinder 1 to the outside. Among them, the axial height of the lead sheet layer 4 is less than the axial height of the inner fixed cylinder 5 and the axial height of the outer fixed cylinder 6.

[0056] Furthermore, the surface of the inner cylinder 1, i.e., the outer peripheral surface of the inner cylinder 1, is polished so that the pit depth of the outer surface of the inner cylinder 1 is less than or equal to 0.25 mm, and the scratch depth is less than or equal to 0.2 mm. Ensure that there is no oil stain and welding bump on the outer surface of the inner cylinder 1 before wrapping, and ensure that the lead plate 41 can be fully fitted with the inner cylinder 1 when it is installed later.

[0057] See also Figures 4 to 7 , is a schematic diagram of performing the first bandaging, including steps S100 to S400. Before bandaging, the inner cylinder 1 is placed horizontally on the ground. Generally, the axial direction of the inner cylinder 1 is parallel to the ground.

[0058] like Figure 4 As shown, step S100: lay multiple layers of lead plates 41 in the radial direction at the same position of the inner cylinder 1, and the adjacent stacked lead plates 41 are tightly fitted, for example, the lead plates 41 are knocked with a rubber hammer to make them fit tightly. And the axial edges of the multiple layers of lead plates 41 are sequentially staggered from the inside to the outside, for example, the staggered form gradually increases from the inside to the outside, or the staggered form gradually decreases from the inside to the outside. It can be understood that each lead plate 41 is provided with axial edges on both sides of the axial direction, and the staggered form gradually increases from the inside to the outside or the staggered form gradually decreases from the inside to the outside can be applied to the axial positions of the multiple layers of lead plates 41 at the same time or separately, for example, the axial edges on both sides of the multiple layers of lead plates 41 are staggered in a form that gradually decreases from the inside to the outside at the same time; or the axial edges on one side of the multiple layers of lead plates 41 are staggered in a form that gradually increases from the inside to the outside, and the axial edges on the other side of the multiple layers of lead plates 41 are staggered in a form that gradually decreases from the inside to the outside. In this embodiment, during the first wrapping, the axial edges on both sides of the multi-layer lead plate 41 are simultaneously offset in a gradually decreasing manner from the inside to the outside.

[0059] The first end of the lead plate 41 abuts against the lower flange surface 3 , and a gap is left between the second end of the lead plate 41 and the upper flange surface 2 .

[0060] Furthermore, the number of the multi-layer lead plates 41 can be three, four, five, etc., that is, the number of the lead plate layers 4 can be three, four, five, etc. The axial edge staggered distance of the multi-layer lead plates 41 is greater than or equal to 50 mm, such as 50 mm, 60 mm, 65 mm, etc. In order to facilitate the installation of the circumferentially adjacent lead plates 41, the lead plates 41 at the same position are sequentially contracted from the inner cylinder 1 to the outside.

[0061] For the convenience of illustration, the inner cylinder 1 is divided into a plurality of position areas, and generally the arc length of each position area of ​​the inner cylinder 1 matches the arc length of the lead plate 41. For example, a plurality of position areas are divided equally, including a, b, c, etc., and appropriate equal divisions are selected according to actual needs, such as three equal divisions, four equal divisions, five equal divisions, etc. Generally, when bandaging, the uppermost position area of ​​the inner cylinder 1 is selected, and the inner cylinder 1 can provide sufficient support force, and the lead plate 41 naturally droops under the action of gravity. For example, in this embodiment, the a position area is at the top, and the bandage is performed on the a position area.

[0062] In some embodiments, the arc lengths of the multiple lead plates 41 of each lead plate layer 4 are the same, and one lead plate 41 is 1 / 4 of the total laid cylinder volume of the lead plate layer 4. For the convenience of illustration, the inner cylinder 1 is divided into four equal parts: a, b, c, and d. It can be understood that in some other embodiments, one lead plate 41 can also be 1 / 3 or 1 / 5 of the total laid cylinder volume of the lead plate layer 4.

[0063] Step S200: Cast molten lead to fill the gap between the second end of the lead plate 41 and the upper flange surface 2, and form a molten lead layer 7 after the molten lead solidifies. Before the molten lead solidifies, part of the molten lead will flow along the gap between the molten lead and the inner cylinder 1, and between the lead plate 41 and the adjacent lead plate 41. After the molten lead solidifies, the lead that is higher than the parent material is removed. The tightness between the lead plate 41 and the upper flange surface 2, the lead plate 41 and the inner cylinder 1, and the lead plate 41 and the adjacent lead plate 41 can be strengthened, and the shielding ability of the lead plate 41 can be further enhanced.

[0064] like Figure 6 As shown, step S300: laying the first insulation layer 8 on the outer side surface of the first end and the outer side surface of the second end of the outermost lead plate 41, respectively, to prevent the subsequent welding operation from affecting the lead plate 41. The first end of the lead plate 41 refers to the end close to the upper flange surface 2, and the second end of the lead plate 41 refers to the end close to the lower flange surface 3. Preferably, the length of the first insulation layer 8 is greater than the arc length of the lead plate 41, and the width of the first insulation layer 8 is greater than or equal to 100 mm, such as 100 mm, 110 mm, etc. The first insulation layer 8 is an insulation cloth made of glass fiber.

[0065] like Figure 5As shown, step S400: the inner layer fixing plate 51 is laid on the outermost layer lead plate 41 and is closely fitted with the outermost layer lead plate 41, the axial edge of the outermost layer lead plate 41 is staggered with the axial edge of the inner layer fixing plate 51, and the two ends of the inner layer fixing plate 51 are respectively welded and fixed to the upper flange surface 2 and the lower flange surface 3. Preferably, the inner layer fixing plate 51 is an arc-shaped steel plate made of carbon steel, and the arc length of the inner layer fixing plate 51 matches the arc length of the outermost layer lead plate 41. In this embodiment, one inner layer fixing plate 51 is 1 / 4 of the total laying cylinder volume of the layer.

[0066] In some embodiments, the staggered distance between the axial edge of the outermost lead plate 41 and the axial edge of the inner fixed plate 51 is greater than or equal to 50 mm, such as 50 mm, 60 mm, 65 mm, etc. Preferably, in this embodiment, the staggered distance between the axial edge of the outermost lead plate 41 and the axial edge of the inner fixed plate 51 is greater than the staggered distance between the axial edges of the multiple lead plates 41.

[0067] In some embodiments, a clamp is used to clamp the inner fixing plate 51 and the lead plate 41 tightly so that the inner fixing plate 51 and the outermost lead plate 41 are closely attached. After welding and fixing, the weld between the inner fixing plate 51 and the upper flange surface 2 and the lower flange surface 3 is polished so that the weld is flush with the surface of the inner fixing plate 51. After confirming that the lead plate 41 is compacted, the clamp is removed. The clamp is not shown in the figure.

[0068] like Figure 7 As shown, according to the above steps S000 to S400, the preparation before bandaging and the first bandaging are completed, and the actual effect of the partial cylinder is obtained. Before the next step, the partial cylinder is rotated 90° clockwise or counterclockwise, that is, the b position area or the d position area is at the top, and the bandaging is continued on the b position area or the d position area.

[0069] See also Figure 8, after the first bandaging is completed, the second bandaging, the third bandaging, etc. are continued, that is, step S500: repeat steps S100 to S400 several times along the circumference of the inner cylinder 1 to finally form multiple cylindrical lead plate layers 4 and cylindrical inner fixed cylinders 5. The number of repetitions is determined according to actual needs. In this embodiment, one inner fixed plate 51 is 1 / 4 of the total amount of the cylinder laid in the layer, and one inner fixed plate 51 is 1 / 4 of the total amount of the cylinder laid in the layer, that is, it takes three repetitions to form multiple cylindrical lead plate layers 4 and cylindrical inner fixed cylinders 5. Among them, in this embodiment, during the second bandaging, the part of the cylinder is rotated 90° counterclockwise so that the b position area is at the top, and then the second bandaging is continued in the b position area. The axial edges of the multi-layer lead plates 41 and the inner fixed plates 51 near position a are displaced in a form of gradually increasing from the inside to the outside, to match the displaced form of the multi-layer lead plates 41 and the inner fixed plates 51 at position a during the first wrapping, which gradually decrease from the inside to the outside. This allows the lead plates 41 and the inner fixed plates 51 to be placed in the corresponding positions by gravity, reducing the difficulty of wrapping. At the same time, the axial edges of the multi-layer lead plates 41 and the inner fixed plates 51 away from position a are displaced in a form of gradually decreasing from the inside to the outside, to reduce the difficulty of the next wrapping. And so on. There is a gap between the adjacent lead plates 41 along the circumferential direction of the inner cylinder 1, and the gap is filled by casting lead water, and the lead that is higher than the parent material is removed.

[0070] See also Fig. 9 , step S500, further includes laying a second heat insulation layer 9 at a specific position outside the outermost lead plate 41, and welding and fixing adjacent inner layer fixing plates 51 in sequence along the circumference of the inner cylinder 1. The specific position is a position opposite to the axial edge of the inner layer fixing plate 51. Preferably, the second heat insulation layer 9 extends along the axial direction of the inner cylinder 1, its length is greater than the axial height of the outermost lead plate 41, and its width is greater than 100mm, and the second heat insulation layer 9 is a glass fiber heat insulation cloth.

[0071] See also Fig.10 and Fig.11, after the second bandage is completed, the third and fourth bandages are performed in sequence, that is, steps S100 to S400 are repeated twice along the circumference of the inner cylinder 1. Before the third bandage is performed, the cylinder is rotated 90° counterclockwise in the direction before the second bandage, so that the c position area is at the top, and the third bandage is performed in the c position area. After the third bandage is completed, before the fourth bandage is performed, the cylinder is rotated 90° counterclockwise in the direction before the third bandage, so that the d position area is at the top, and the fourth bandage is performed in the d position area. During the fourth wrapping, the axial edges on both sides of the multi-layer lead plate 41 and the inner fixed plate 51 are displaced in a gradually increasing manner from the inside to the outside, to match the displaced manner of the multi-layer lead plate 41 and the inner fixed plate 51 at position a during the first wrapping, which is gradually decreasing from the inside to the outside, and the displaced manner of the multi-layer lead plate 41 and the inner fixed plate 51 at position c during the third wrapping, which is gradually decreasing from the inside to the outside. Similarly, during the third and fourth wrappings, the methods of pouring lead water and laying the second heat insulation layer 9 are the same as those of the second wrapping, and will not be repeated here.

[0072] See also Fig.12 After the fourth bandaging is completed, the step S600 is continued: a plurality of layers of outer fixed cylinders 6 are laid outside the inner fixed cylinder 5. The number of the outer fixed cylinders 6 can be one, two, three, etc., according to actual needs.

[0073] In some embodiments, the number of outer fixed cylinders 6 is at least two, and each layer of outer fixed cylinders 6 includes the same number of outer fixed plates 61 as the number of inner fixed plates 51, and the axial edges of the inner fixed plates 51 and the axial edges of at least two layers of outer fixed plates 61 are staggered from the inside to the outside. Two adjacent outer fixed plates 61 on the same layer of outer fixed cylinders are welded and fixed. In this embodiment, one outer fixed plate 61 is 1 / 4 of the total amount of cylinders laid in the layer.

[0074] Further, the staggered distance between the axial edge of the inner fixing plate 51 and the axial edge of at least two outer fixing plates 61 is greater than or equal to 50 mm, such as 50 mm, 60 mm, 65 mm, etc. Preferably, in this embodiment, the staggered distance between the axial edge of the inner fixing plate 51 and the axial edge of at least two outer fixing plates 61 is greater than the staggered distance between the axial edges of the multiple lead plates 41.

[0075] According to the above-mentioned barrel manufacturing method, the present invention can manufacture the following Figure 2 The barrel structure of one embodiment shown in the figure, the barrel manufacturing method and the barrel structure of the present invention have the following advantages:

[0076] 1. A four-stage lead plate 41 wrapping method is adopted, and four layers of lead plates 41 and an external compacted carbon steel plate, i.e., an inner fixed plate 51, are wrapped synchronously, which effectively reduces the fluidity of the lead plate 41 and reduces the construction difficulty.

[0077] 2. Each layer of lead plates 41 is staggered one by one, and the interfaces of each layer of lead plates 41 are filled with lead water for two wrappings. After the lead water is cooled, the excess lead is mechanically removed to achieve splicing of each layer of lead plates 41, thereby improving the uniformity of the lead plates 41 and effectively ensuring the shielding effect of the lead plates 41.

[0078] 3. The carbon steel plates, i.e. the inner fixing plate 51 and the outer fixing plate 61 are respectively spliced ​​by welding. Before welding, glass fiber heat insulation cloth is used to isolate the carbon steel plate weld and the lead plate 41 to prevent the lead plate 41 from melting and improve the uniformity of the lead plate 41.

[0079] 4. The lead plate 41 has a high degree of fit with the outer wall of the inner cylinder 1 and the inner wall of the inner fixing plate 51. The lead plate 41 is compacted firmly and is not easily dislocated during long-term use.

[0080] By implementing the present invention, the following beneficial effects are achieved:

[0081] The cylinder manufacturing method of the nuclear power plant pressure vessel shielding top cover of the present invention can effectively make the lead plate 41 fit and wrap around the surface of the inner cylinder 1, improve the uniformity of the thickness of the lead plate 41 on the circumference of the inner cylinder 1, reduce the deviation, dislocation, wrinkles, bulging and the like of the lead plate 41 during the wrapping process, reduce the difficulty of manufacturing and construction, improve the wrapping accuracy of the lead plate 41, and effectively reduce the fluidity of the lead plate 41.

[0082] The inner cylinder of the cylinder structure of the present invention can fit tightly between the lead plate layer, the adjacent lead plate layers, the lead plate layer and the lead inner layer fixed cylinder, the inner layer fixed cylinder and the outer layer fixed cylinder, and the adjacent outer layer fixed cylinder. The axial edges of the multiple layers of lead plates are staggered, and the gaps between adjacent lead plates on the same layer are filled by pouring lead water to achieve splicing of each lead plate layer, thereby improving the uniformity of the lead plates, effectively ensuring the shielding effect of the lead plates, and preventing dislocation during long-term use.

[0083] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, without departing from the concept of the present invention, the above embodiments or technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the present invention, that is, the embodiments described in "some embodiments" can be freely combined with any of the above and below embodiments. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A method for manufacturing a cylinder of a shielding top cover of a nuclear power plant pressure vessel, characterized in that: The following steps are involved: S000: The inner cylinder (1) is connected and fixed to the upper flange surface (2) and the lower flange surface (3) respectively; S100: laying multiple layers of lead plates (41) in sequence along the radial direction at the same position of the inner cylinder (1), with the adjacent stacked lead plates (41) tightly fitted, and the axial edges of the multiple layers of lead plates (41) being staggered in sequence from the inside to the outside; The inner cylinder (1) is placed horizontally, the first end of the lead plate (41) is in contact with the lower flange surface (3), and a gap is left between the second end of the lead plate (41) and the upper flange surface (2); S200: pouring molten lead to fill the gap, and waiting for the molten lead to solidify to form a molten lead layer (7); S300: laying a first heat insulation layer (8) on the outer side surface of the first end and the outer side surface of the second end of the outermost lead plate (41); S400: Laying the inner fixing plate (51) on the outermost lead plate (41) and closely fitting it with the outermost lead plate (41), the axial edge of the outermost lead plate (41) and the axial edge of the inner fixing plate (51) are offset, and the two ends of the inner fixing plate (51) are respectively welded and fixed to the upper flange surface (2) and the lower flange surface (3); S500: repeating steps S100 to S400 several times along the circumference of the inner cylinder (1) to finally form a plurality of cylindrical lead plate layers (4) and a cylindrical inner fixed cylinder (5); S600: laying a plurality of layers of outer fixed cylinders (6) outside the inner fixed cylinder (5).

2. The method for manufacturing a cylinder of a shielding top cover of a nuclear power plant pressure vessel according to claim 1, characterized in that: Step S500 also includes laying a second heat insulation layer (9) at a specific position outside the outermost lead plate (41), and welding and fixing adjacent inner layer fixing plates (51) in sequence along the circumference of the inner cylinder (1); The specific position is a position opposite to the axial edge of the inner layer fixing plate (51).

3. The method for manufacturing a cylinder of a shielding top cover of a nuclear power plant pressure vessel according to claim 1, characterized in that: One of the lead plates (41) accounts for 1 / 4 of the total laid cylinder volume of the lead plate layer (4), and one of the inner layer fixed plates (51) accounts for 1 / 4 of the total laid cylinder volume of the layer; In step S500, steps S100 to S400 are repeated three times along the circumference of the inner cylinder.

4. The method for manufacturing a cylinder of a shielding top cover of a nuclear power plant pressure vessel according to claim 1, characterized in that: In step S600, the number of the outer layer fixed cylinder (6) is at least two, each layer of the outer layer fixed cylinder (6) comprises the same number of outer layer fixed plates (61) as the number of the inner layer fixed plates (51), and the axial edges of the inner layer fixed plates (51) and the axial edges of at least two layers of the outer layer fixed plates (61) are sequentially staggered from the inside to the outside; Two adjacent outer layer fixing plates (61) on the same layer of the outer layer fixing cylinder are fixed by welding.

5. The method for manufacturing a cylinder of a shielding top cover of a nuclear power plant pressure vessel according to claim 1, characterized in that: Step S000 also includes grinding the surface of the inner cylinder (1) so that the pit depth of the outer surface of the inner cylinder (1) is less than or equal to 0.25 mm, and the scratch depth is less than or equal to 0.2 mm.

6. The method for manufacturing a cylinder of a shielding top cover of a nuclear power plant pressure vessel according to any one of claims 1 to 5, characterized in that: In step S400, the inner fixing plate (51) and the lead plate (41) are tightly clamped by using a clamp so that the inner fixing plate (51) and the outermost lead plate (41) are tightly fitted; After welding and fixing, grinding the welds between the inner layer fixing plate (51) and the upper flange surface (2) and the lower flange surface (3) so that the welds are flush with the surface of the inner layer fixing plate (51); After the lead plate (41) is confirmed to be compacted, the clamp is removed.

7. The method for manufacturing a cylinder of a shielding top cover of a nuclear power plant pressure vessel according to any one of claims 1 to 5, characterized in that: The axial edge offset distance of the multiple layers of the lead plates (41) is greater than or equal to 50 mm; the axial edge of the outermost layer of the lead plates (41) and the axial edge of the inner layer of the fixed plate (51) are offset by greater than or equal to 50 mm.

8. The method for manufacturing a cylinder of a shielding top cover of a nuclear power plant pressure vessel according to claim 2, characterized in that: The length of the first heat insulation layer (8) is greater than the arc length of the lead plate (41), and the width of the first heat insulation layer (8) is greater than or equal to 100 mm; The length of the second heat insulation layer (9) is greater than the axial height of the lead plate (41), and the width of the second heat insulation layer (9) is greater than or equal to 100 mm.

9. The method for manufacturing a cylinder of a shielding top cover of a nuclear power plant pressure vessel according to any one of claims 1 to 5, characterized in that: The number of the lead plate layers (4) is four.

10. A cylinder structure manufactured by the cylinder manufacturing method according to any one of claims 1 to 9, characterized in that: The invention comprises an inner cylinder (1), an upper flange surface (2), a lower flange surface (3), a plurality of lead plate layers (4), an inner fixed cylinder (5) and a plurality of outer fixed cylinders (6); the inner cylinder (1) is respectively connected and fixed to the upper flange surface (2) and the lower flange surface (3); the plurality of lead plate layers (4) are sleeved on the outer circumference of the inner cylinder (1) and respectively connected and fixed to the upper flange surface (2) and the lower flange surface (3); the inner fixed cylinder (5) is sleeved on the outer circumference of the outermost lead plate layer (4) and respectively connected and fixed to the upper flange surface (2) and the lower flange surface (3); the plurality of outer fixed cylinders (6) are sleeved on the inner fixed cylinder (5) and respectively connected and fixed to the upper flange surface (2) and the lower flange surface (3); Each of the lead plate layers (4) comprises a plurality of lead plates (41); gaps are left between adjacent lead plates (41) of the same lead plate layer (4) and the plates are connected and fixed by lead water; adjacent stacked lead plates (41) are tightly fitted, and the axial edges of the multiple layers of lead plates (41) are staggered in sequence from the inside to the outside.

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