A vertical container structure and construction method for dry storage of UHPC spent fuel

Abstract

The present invention discloses a UHPC spent fuel dry storage vertical container structure and construction method, belonging to the technical field of spent fuel dry storage. The container comprises a bottom plate; a cylinder shell fixedly connected to the bottom plate; a concrete cylinder arranged around the cylinder shell; a top cover installed on the upper part of the concrete cylinder and the cylinder shell, and a base installed on the bottom plate; a plurality of reinforcing steel bars welded to the outer surface of the cylinder shell; an upper ring plate welded to the top of the cylinder shell; the concrete cylinder is formed by layered casting and curing, with the cylinder shell as the inner mold, the bottom plate as the bottom mold, the steel template as the outer mold, and the upper ring plate as the top mold. The steel template is removable, which facilitates the inspection of the construction quality and defects of the concrete cylinder, and enables non-destructive testing of the concrete cylinder during in-service operation and maintenance. Reinforcement steel bars are welded to the cylinder shell in advance, which facilitates construction and ensures welding quality. By leveraging the high strength and high bonding properties of UHPC concrete, the overall reinforcement amount is reduced, the cylinder wall thickness is reduced, and the site utilization rate is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of spent fuel dry storage, and in particular relates to a UHPC spent fuel dry storage vertical container structure and a construction method. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] In nuclear power plants, spent fuel storage can be divided into wet storage (pool storage) and dry storage. Because wet storage poses significant safety risks, dry storage, using specialized containers, is currently recommended. Vertical containers for dry spent fuel storage are typically reinforced concrete. To ensure adequate shielding performance, reinforced concrete containers typically have thick walls, resulting in low site utilization.

[0004] A prior art document describes a steel-concrete structure module for dry storage of high-burnup spent fuel. The module comprises a roof, a cylinder, and a base. The cylinder consists of concentrically arranged inner and outer steel shells, with studs welded between them. Concrete is then poured to form the steel-concrete structure. This reduces the container's wall thickness and improves site utilization.

[0005] The following problems exist in adopting this steel plate concrete container:

[0006] The container is quite high, and the bolts and both sides of the reinforcement are welded to the inner and outer steel shells. The limited space makes the operation difficult and the welding quality cannot be guaranteed. The concrete can only be poured as a whole on the top of the inner and outer steel shells, which results in too thick a material being added at one time and insufficient vibration, which affects the density of the concrete and reduces the concrete strength. The concrete is enclosed by the outer steel shell, and non-destructive testing (such as the rebound method) of the aging state of the internal concrete cannot be performed through the outer steel shell during service. Summary of the Invention

[0007] To address the above-mentioned problems, the present invention provides a UHPC spent fuel dry storage vertical container structure and construction method. The container uses a cylinder shell as an inner mold, a bottom plate as a bottom mold, a steel formwork as an outer mold, and an upper ring plate as a top mold. UHPC concrete is poured and cured in layers to form a concrete cylinder. The steel formwork is removable, facilitating inspection of the concrete cylinder's construction quality and defects, and enabling direct non-destructive testing of the concrete cylinder during in-service operation and maintenance. Reinforced steel bars are pre-welded to the cylinder shell, facilitating construction and ensuring welding quality. The high strength and high adhesion properties of UHPC concrete can significantly reduce the overall reinforcement amount, reduce the cylinder wall thickness, and improve site utilization. Multiple layers of casting holes are provided in the steel formwork to avoid insufficient vibration during one-time feeding, which would lead to a decrease in concrete strength, and to avoid concrete segregation due to excessive feeding height, thereby ensuring cylinder strength.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] In a first aspect, a vertical container structure for dry storage of UHPC spent fuel is provided, comprising:

[0010] base plate;

[0011] The hollow cylindrical shell is fixedly connected to the bottom plate; the concrete cylinder is arranged around the shell;

[0012] and a top cover mounted on the upper part of the concrete cylinder and the cylinder shell, and a base mounted on the bottom plate;

[0013] Several reinforcing steel bars are welded on the outer surface of the cylinder shell; a ring plate is welded on the top of the cylinder shell;

[0014] The concrete cylinder uses the cylinder shell as the inner mold, the bottom plate as the bottom mold, the steel formwork as the outer mold, and the upper ring plate as the top mold. It is made by layered pouring and curing of UHPC concrete.

[0015] Preferably, the steel formwork is provided with multiple layers of casting holes in the axial direction; multiple casting holes are provided in each layer, and the multiple casting holes in the same layer are evenly arranged along the circumference of the steel formwork.

[0016] Preferably, the steel formwork is composed of a plurality of sector-shaped cylindrical plates that are fastened together and fixedly connected; a plurality of annular stiffening ribs are evenly welded along the axial direction on the outer wall of the sector-shaped cylindrical plate, and a plurality of vertical stiffening ribs are evenly arranged along the circumferential direction; the annular stiffening ribs and the vertical stiffening ribs form a plurality of force-bearing units to enhance the strength of the sector-shaped cylindrical plate.

[0017] Preferably, the pouring hole needs to be set above the annular stiffening rib, and slot plates are welded on both sides of the pouring hole, and the bottom of the slot plate is fixedly connected to the annular stiffening rib; after layered pouring, a sealing plate is inserted into the inner side of the slot plate to seal the pouring hole.

[0018] Preferably, after the concrete cylinder is poured, a multi-layer cylindrical insulation layer is provided on the outside of the steel formwork, and the insulation layer is made of polystyrene board, polyurethane board or extruded board.

[0019] Preferably, the cylinder shell includes a first cylindrical plate and a second cylindrical plate, the diameter of the first cylindrical plate is larger than that of the second cylindrical plate, and a horizontal first annular plate is arranged between the first cylindrical plate and the second cylindrical plate to form a stepped structure.

[0020] Preferably, the top cover includes a top cover shell with an opening at the top, and the base includes a base shell with an opening at the top. Reinforced steel bars are welded inside the top cover shell or the base shell and are filled with UHPC concrete.

[0021] Preferably, a third ring plate is welded to the top of the side wall of the top cover shell, and the third ring plate covers the connection seam between the top cover and the cylinder shell.

[0022] Preferably, an air inlet is provided at the bottom of the cylindrical shell, and an air inlet is provided at the top; the air inlet is welded to an air inlet steel pipe, and the exhaust port is welded to an exhaust steel pipe.

[0023] In a second aspect, a construction method for the above-mentioned vertical container structure for dry storage of UHPC spent fuel is provided, and the specific steps are as follows:

[0024] Prefabricate the bottom plate, cylinder shell, top cover shell, and base shell, and weld reinforcing steel bars on the cylinder shell, top cover shell, and base shell; prefabricate steel formwork and reserve casting holes;

[0025] Install the bottom plate and weld and fix the cylinder shell, and tie the steel bars; then hoist, surround and fix the steel formwork outside the cylinder shell;

[0026] UHPC concrete is poured layer by layer into the sealed cavity. After pouring, multiple layers of insulation are placed around the steel formwork. The top cover and base are poured simultaneously with the concrete cylinder, and the insulation layer is used to maintain the top cover and base. The UHPC concrete is cured to the specified strength, and the number of insulation layers can be adjusted dynamically according to the ambient temperature during the curing period.

[0027] After curing, the insulation layer and steel formwork are removed; then the base is installed on the base plate, and finally the top cover is installed.

[0028] Compared with the prior art, the present invention has the following advantages and positive effects:

[0029] The concrete cylinder in the present invention uses the cylinder shell as the inner formwork, the bottom plate as the bottom formwork, the steel formwork as the outer formwork, and the upper ring plate as the top formwork. It is constructed by layered casting and curing of UHPC concrete. The steel formwork is removable, facilitating the inspection of the concrete cylinder's construction quality and defects, and enabling direct non-destructive testing (such as the rebound method) of the concrete cylinder during in-service operation and maintenance. Pre-welding of reinforcing steel bars on the cylinder shell facilitates construction and ensures welding quality. Leveraging the high strength and high adhesion properties of UHPC concrete, the overall reinforcement requirement can be significantly reduced, the cylinder wall thickness can be reduced, and site utilization can be improved. Multiple layers of casting holes are provided in the steel formwork to avoid insufficient vibration during a single feed, which would result in reduced concrete strength, and to prevent concrete segregation due to excessive feed height, thereby ensuring cylinder strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0031] Figure 1 is a cross-sectional view of the vertical container structure of embodiment 1 or 2 of the present invention;

[0032] Figure 2is a cross-sectional view of the vertical container structure and steel template of Example 1 or 2 of the present invention;

[0033] Figure 3 This invention Figure 1 Cross-section at AA;

[0034] Figure 4 This invention Figure 2 Cross-section at the middle BB;

[0035] Figure 5 is a cross-sectional view of the top cover of embodiment 1 or 2 of the present invention;

[0036] Figure 6 is a cross-sectional view of the base of embodiment 1 or 2 of the present invention;

[0037] Figure 7 is a cross-sectional view of the cylindrical shell of Example 1 or 2 of the present invention;

[0038] Figure 8 It is a local reinforcement arrangement diagram of the cylindrical shell of embodiment 1 or 2 of the present invention;

[0039] Figure 9 is a partial cross-sectional view of the steel formwork of embodiment 1 or 2 of the present invention;

[0040] Figure 10 This invention Figure 4 Enlarged view of point C in the middle;

[0041] Figure 11 is a front view of the casting hole of Example 1 or 2 of the present invention;

[0042] Figure 12 Schematic diagram of the connection between adjacent sector-shaped cylinder plates in Example 1 or 2 of the present invention;

[0043] In the picture:

[0044] 1. Bottom plate; 2. Cylinder shell; 21. Reinforcement steel bars; 22. First cylindrical plate; 23. First ring plate; 24. Second cylindrical plate; 25. Inlet steel pipe; 26. Exhaust steel pipe; 27. Upper ring plate; 28. Vertical main reinforcement; 29. ​​Circumferential main reinforcement; 3. Concrete cylinder; 4. Top cover; 41. Top cover shell; 42. Third cylindrical plate; 43. Fourth cylindrical plate; 44. Second ring plate; 45. Third ring plate; 46. First circular plate; 5. Base; 51. Second circular plate; 52. Fifth cylindrical plate; 6. Steel formwork; 61. Sector cylindrical plate; 62. Annular stiffening ribs; 63. Vertical stiffening ribs; 64. Casting hole; 65. Slot plate; 66. Sealing plate; 67. Insulation layer; 68. Connecting plate. DETAILED DESCRIPTION

[0045] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0046] Glossary:

[0047] UHPC concrete: Ultra-high performance concrete, with ultra-high durability and ultra-high mechanical properties.

[0048] The present invention will be described in detail below with reference to the accompanying drawings.

[0049] Example 1

[0050] This embodiment discloses a vertical container structure for dry storage of UHPC spent fuel, such as Figure 1 As shown, it includes a base plate 1; a hollow cylindrical shell 2 fixedly connected to the base plate 1, and an air inlet and an air outlet are provided on the shell 2; a concrete cylinder 3 is arranged around the shell 2; and a top cover 4 installed on the concrete cylinder 3 and the upper part of the shell 2, and a base 5 installed on the base plate 1.

[0051] like Figure 1 As shown, the base plate 1 is a circular steel plate, and the cylinder shell 2 is a hollow steel cylinder. The cylinder shell 2 sits atop the base plate 1, and the two are welded together to form the main metal structure of the vertical vessel. The base 5, top cover 4, and cylinder shell 2 together form an annular cavity for storing spent fuel; the fuel tank can be placed within this annular cavity.

[0052] like Figure 1 、 Figure 7 As shown, a plurality of reinforcing steel bars 21 are welded on the outer surface of the cylinder shell 2, and the concrete cylinder 3 is cast using UHPC concrete. During casting, the UHPC concrete is connected to the reinforcing steel bars 21, so that the reinforcing steel bars 21 and the concrete cylinder 3 are combined to form an integrated structure; at the same time, the cylinder shell 2 and the concrete cylinder 3 are connected as a whole, making the overall strength higher.

[0053] In this embodiment, UHPC concrete is used to cast in situ the concrete cylinder 3. UHPC concrete has ultra-high durability and ultra-high mechanical properties. With the help of the high strength and high adhesion characteristics of UHPC concrete, the overall reinforcement amount can be greatly reduced, thereby reducing the thickness of the concrete cylinder 3 and improving site utilization.

[0054] In this embodiment, if Figure 1 、 Figure 2 、 Figure 4 、 Figure 7As shown, a ring plate 27 is welded to the top of the cylinder shell 2 as the top formwork for the concrete cylinder 3. The cylinder shell 2 serves as the inner formwork, the bottom plate 1 serves as the bottom formwork, and a removable steel formwork 6 serves as the outer formwork. Layered casting and curing are employed to form the concrete cylinder 3. The advantages of providing a removable outer formwork and layered casting are that, due to the high height of the cylinder shell 2, reinforcing steel bars 21 can be welded to the cylinder shell 2 before installing the steel formwork 6; and layered casting ensures the integrity and good performance of the concrete cylinder 3.

[0055] like Figure 1 、 Figure 3 、 Figure 7 、 Figure 8 As shown, the reinforcing steel bars 21 are arranged horizontally in several layers with equal inter-layer spacing. A bent anchor section is provided at one end away from the cylindrical shell 2, and the whole is in the shape of an umbrella handle. Circumferential main bars 29 are tied to each layer of reinforcing steel bars 21, and vertical main bars 28 are also tied to the circumferential main bars 29 and the reinforcing steel bars 21 between layers.

[0056] Because the height of the concrete cylinder 3 is relatively high, when pouring the whole concrete, the density of the concrete will be affected due to the excessive thickness of the material added at one time, which will lead to insufficient vibration. At the same time, too high a material feeding height will also cause concrete segregation, resulting in reduced strength of the concrete cylinder 3.

[0057] Compared with the traditional steel plate concrete structure, after the inner and outer steel plates are set, the cavity between the inner and outer steel shells is entered to weld the two ends of the bolts or tie bars to the inner and outer steel shells. In this embodiment, the reinforcing steel bars 21 are welded to the cylindrical shell 2 before the steel formwork 6 is installed, which makes the operation more convenient and can further ensure the quality of the welding.

[0058] like Figure 2 、 Figure 4 、 Figure 7 As shown, the cylinder shell 2 is used as the inner mold, the bottom plate 1 is used as the bottom mold, the removable steel template 6 is used as the outer mold, and the upper ring plate 27 is used as the top mold to form a sealed cavity. UHPC concrete is filled in the sealed cavity. After solidification and curing, the steel template 6 is removed to form the concrete cylinder 3.

[0059] Since the height of the concrete cylinder 3 is relatively high, it is necessary to adopt layered pouring. The steel formwork 6 can be removed after the concrete cylinder 3 is cured and does not participate in the force of the concrete cylinder 3. In order to achieve layered pouring, Figure 2 As shown, multiple layers of casting holes 64 are provided axially along the steel formwork. UHPC concrete is poured through each layer of casting holes 64 into the sealed cavity between the cylinder shell 2, the bottom plate 1, the steel formwork 6, and the upper ring plate 27. In this embodiment, three layers of casting holes 64 are provided, and the vertical spacing of the casting holes 64 is uniform.

[0060] Further, if Figure 4 As shown, multiple pouring holes 64 are provided on each layer, and the multiple pouring holes 64 on the same layer are evenly spaced along the circumference of the steel formwork. In this embodiment, there are eight pouring holes 64 on each layer. During pouring, pouring pipes are inserted into each of the eight pouring holes 64 on the same layer, and UHPC concrete is poured simultaneously into the interior of the steel formwork 6, ensuring that the UHPC concrete evenly fills the sealed cavity.

[0061] Furthermore, the steel template 6 is composed of a plurality of sector-shaped cylindrical plates 61 which are fastened to each other and fixedly connected; Figure 2 、 Figure 4 、 Figure 9 As shown, in order to ensure the strength of the steel formwork 6, multiple horizontal annular stiffening ribs 62 are evenly welded along the axial direction on the outer wall of the sector-shaped cylinder plate 61, and multiple vertical stiffening ribs 63 are evenly arranged along the circumferential direction. The annular stiffening ribs 62 and the vertical stiffening ribs 63 form a force-bearing unit, thereby strengthening the strength of the sector-shaped cylinder plate 61 to resist the pressure generated in the sealed cavity when pouring UHPC concrete.

[0062] In this embodiment, there are two sector-shaped cylindrical plates 61 .

[0063] Furthermore, if Figure 12 As shown, in order to ensure the stability of the connection between the sector-shaped cylindrical plates 61, a connecting plate 68 is provided on one side of the cylinder wall of the sector-shaped cylindrical plate 61, but not on the other side; one side of the connecting plate 68 of the sector-shaped cylindrical plate 61 is connected to the side of the adjacent sector-shaped cylindrical plate 61 where the connecting plate 68 is not provided, and the connection is made by using a plurality of fasteners. In this embodiment, bolts are used for connection.

[0064] Furthermore, if Figure 2 、 Figure 4 、 Figure 9 、 Figure 10 、 Figure 11 As shown, the pouring hole 64 needs to be located above the annular stiffening rib 62, and slot plates 65 are fixedly welded on both sides of the pouring hole 64. The bottom of the slot plates 65 is fixedly connected to the annular stiffening rib 62. The slot plates 65 have the function of limiting the left and right shaking of the pouring pipe. The second function is to withdraw the pouring pipe after the current layer of pouring is completed. The plugging plate 66 is inserted into the slot plate 65 and together with the plugging plate 66, the pouring hole 64 is sealed. The height of the plugging plate 66 is greater than the diameter of the pouring hole 64.

[0065] Optimally, the top of the steel formwork 6 is higher than the upper ring plate 27. At the same time, an auxiliary pouring hole (not shown in the figure) is also opened at the outer edge of the upper ring plate 27 (i.e., the edge of the side away from the cylinder shell 2) to pour the top layer of UHPC concrete from top to bottom to ensure that the UHPC concrete fills the sealed cavity.

[0066] like Figure 2 、 Figure 4 、 Figure 9 As shown, after the pouring of the concrete cylinder 3 is completed, insulation and curing are required. A multi-layer cylindrical insulation layer 67 is set on the outside of the steel formwork 6. The insulation layer 67 is made of polystyrene board, polyurethane board or extruded board. These materials have good insulation performance and compressive resistance.

[0067] In this embodiment, three layers of insulation 67 are provided. The number of layers is determined based on the difference between the ambient temperature and the target curing temperature. It should be noted that the number of layers can be dynamically adjusted based on the ambient temperature during curing. For example, as the temperature decreases, the number of layers can be increased, while as the temperature increases, the number of layers can be decreased.

[0068] like Figure 1 As shown, the top cover 4 is connected to the cylinder shell 2 and the concrete cylinder 3 using a stepped structure. Specifically, as shown in FIG. Figure 7 As shown, the cylindrical shell 2 includes a first cylindrical plate 22, a first annular plate 23, and a second cylindrical plate 24. The first cylindrical plate 22 and the second cylindrical plate 24 are arranged concentrically, and the diameter of the first cylindrical plate 22 is larger than that of the second cylindrical plate 24. The first cylindrical plate 22 and the second cylindrical plate 24 are welded to the upper and lower surfaces of the first annular plate 23, respectively, to form a stepped structure for mating with the top cover 4. A top annular plate 27 is welded to the top of the first cylindrical plate 22, serving as the top form for the concrete cylinder 3 and also sealing the joint between the cylindrical shell 2 and the top cover 4.

[0069] like Figure 5 As shown, the top cover 4 includes a top cover shell 41, and reinforcing steel bars 21 are also welded inside the top cover shell 41. The reinforcing steel bars 21 are vertically arranged inside the top cover 4. Horizontal main bars and circumferential main bars are also arranged. The top cover shell 41 is filled with UHPC concrete.

[0070] Specifically, the top cover shell 41 includes a third cylindrical plate 42, a fourth cylindrical plate 43, and a second ring plate 44. The third cylindrical plate 42 and the fourth cylindrical plate 43 are concentrically arranged, and the diameter of the fourth cylindrical plate 43 is larger than the diameter of the third cylindrical plate 42. The third cylindrical plate 42 and the fourth cylindrical plate 43 are respectively welded to the upper and lower surfaces of the second ring plate 44 to form a stepped structure; which is used to cooperate with the cylinder shell 2.

[0071] It should be noted that the outer wall diameter of the fourth cylindrical plate 43 is equal to the inner wall diameter of the first cylindrical plate 22 , so that the outer wall of the top cover 4 fits tightly with the inner wall of the cylinder shell 2 .

[0072] like Figure 5As shown, the first circular plate 46 is welded to the bottom of the third cylindrical plate 42 , and the third cylindrical plate 42 , the fourth cylindrical plate 43 , the second annular plate 44 , and the first circular plate 46 form a top cover shell 41 . Reinforced steel bars are welded inside the top cover shell 41 and filled with UHPC concrete to form the top cover 4 .

[0073] like Figure 5 As shown, to enhance sealing, a third ring plate 45 is welded to the top of the fourth cylindrical plate 43. The third ring plate 45 covers the joint between the top cover 4 and the cylindrical shell 2 to prevent leakage of radioactive material. In some embodiments, a steel plate is provided between the third ring plate 45 and the upper ring plate 27 to further enhance sealing between the top cover 4 and the cylindrical shell 2.

[0074] like Figure 6 As shown, the base 5 comprises a base shell with reinforced steel bars 21 welded inside. The reinforced steel bars 21 are vertically arranged within the base 5. Horizontal and circumferential main bars are also provided. The base shell is also filled with UHPC concrete. The base shell comprises a second circular plate 51, to which a fifth cylindrical plate 52 is welded circumferentially. The reinforced steel bars 21 are welded to the second circular plate 51. Subsequently, the second circular plate 51 and the fifth cylindrical plate 52 are filled with UHPC concrete to form the base 5. A fuel tank is placed on the base 5.

[0075] like Figure 1 As shown, the diameter of the fifth cylindrical plate 52 is smaller than the diameter of the cylindrical shell 2 by a set distance, forming a certain gap between the base 5 and the cylindrical shell 2, which is used to guide a part of the radioactive particles to leak into the gap and reduce leakage to the external environment.

[0076] like Figure 1 、 Figure 7 As shown, an air inlet is provided at the bottom of the cylinder shell 2, and an air exhaust port is provided at the top; an air intake steel pipe 25 is welded at the air inlet, and an exhaust steel pipe 26 is welded at the exhaust port. The air intake steel pipe 25 and the exhaust steel pipe 26 are both arranged horizontally, and the air intake steel pipe 25 and the exhaust steel pipe 26 extend from one end of the cylinder shell 2 to the outer wall of the concrete cylinder 3 (i.e., the inner wall of the steel formwork 6).

[0077] like Figure 1 As shown, the annular cavity communicates with the outside atmosphere via an air intake pipe 25 and an exhaust pipe 26, thereby forming a passive natural convection channel along the annular cavity's axial direction between the inner wall of the cylindrical shell 2 and the outer surface of the spent fuel container. The air intake is located at a set distance from the bottom of the top surface of the base 5, and the exhaust is located at a set distance from the bottom of the first ring plate 23, effectively reducing air flow resistance and improving waste heat removal capabilities.

[0078] In this embodiment, the base 5 and the top cover 4 can be prepared in advance in a prefabricated manner; they can be hoisted after the concrete cylinder 3 is cured; it can be understood that lifting holes or welded lifting rings can be reserved in advance on the steel structure shell of the base 5 and the top cover 4.

[0079] On-site construction is also possible, that is, before the cylinder shell 2 is welded to the bottom plate 1, the base 5 is constructed first; after the concrete cylinder 3 is cured, the top cover 4 is constructed.

[0080] Furthermore, a centering hole is reserved at the center of the bottom of the base shell of the base 5, and a centering hole steel pipe is welded and fixed to the centering hole. At least one limiting hole is reserved at other positions on the bottom of the base shell, and a limiting hole steel pipe is welded and fixed to the limiting hole. At the same time, a centering pin is welded and fixed in advance at the center of the bottom plate 1, and limiting pins are welded and fixed at corresponding positions. This can position and limit the base shell of the base 5 on the bottom plate 1. This allows the base 5 to be positioned and limited regardless of whether the base 5 is cast in situ first and then the concrete cylinder 3 is poured, or whether the base 5 is prefabricated and then installed on the bottom plate 1.

[0081] In this embodiment, the concrete cylinder 3 made with the cylinder shell 2 as the inner mold has a better connection and sealing with the top cover 4 than the traditional reinforced concrete structure, and the cylinder thickness is lower; compared with the steel plate concrete structure, the concrete cylinder 3 has no steel plate seal on the outside, which is convenient for detecting the construction quality and defects of the UHPC concrete, and can also be directly non-destructively tested on the concrete cylinder 3 during in-service operation and maintenance. In addition, during the construction phase, reinforcing steel bars can be welded on the cylinder shell 2 in advance, which makes construction more convenient and the welding quality easier to ensure; and it can achieve layered pouring, avoid insufficient vibration at one time, resulting in reduced concrete strength, avoid excessive height of the material being dropped and resulting in concrete segregation, and ensure the strength of the cylinder.

[0082] Example 2

[0083] This embodiment provides a construction method for a vertical container structure for dry storage of UHPC spent fuel, which utilizes the vertical container structure for dry storage of UHPC spent fuel disclosed in Example 1. The specific steps are as follows:

[0084] Prefabricate the bottom plate, cylinder shell, top cover shell and base shell, and weld reinforcing steel bars on the cylinder shell, top cover shell and base shell; prefabricate the steel formwork 6, reserve casting holes, and weld the slot plates; by prefabricating each steel component, the construction period can be saved.

[0085] The base plate is installed on site and the cylinder shell is welded and fixed, and then the steel bars are tied to the reinforcing bars; since there are no other components on the outside of the cylinder shell, it is more convenient to tie the steel bars to the reinforcing bars.

[0086] Then, the steel formwork 6 is hoisted, enclosed, and fixed outside the cylinder shell to prepare for pouring;

[0087] UHPC concrete is poured layer by layer into the sealed cavity. After pouring, multiple layers of insulation layer 67 are placed around the outside of the steel formwork 6. While pouring the concrete cylinder 3, the top cover 4 and base 5 are poured and cured with the insulation layer 67. The UHPC concrete is cured to the specified strength. During the curing period, the number of layers of insulation layer 67 can be dynamically adjusted according to the ambient temperature.

[0088] For example, when the temperature drops, the number of insulation layers 67 is increased, and when the temperature rises, the number of insulation layers 67 is reduced.

[0089] After the curing is completed, remove the insulation layer and steel formwork on the outside of the concrete cylinder 3, and remove the insulation layer on the outside of the top cover 4 and the base 5; then install the base 5 on the bottom plate 1, and during installation, insert the centering pin and limit pin of the bottom plate 1 into the centering hole and limit hole at the bottom of the base 5; finally, install the top cover 4.

[0090] Pouring the top cover 4 and the base 5 at the same time as the concrete cylinder 3 can not only save construction time, but also enable the concrete cylinder 3, the top cover 4 and the base 5 to use concrete from the same period to ensure consistent strength, while also ensuring consistent curing conditions (ambient temperature and curing days for the same period of pouring).

[0091] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A vertical container structure for dry storage of UHPC spent fuel, characterized in that: include: base plate; The hollow cylindrical shell is fixedly connected to the bottom plate; the concrete cylinder is arranged around the shell; and a top cover mounted on the upper part of the concrete cylinder and the cylinder shell, and a base mounted on the bottom plate; Several reinforcing steel bars are welded on the outer surface of the cylinder shell. The end of the reinforcing steel bar away from the cylinder shell is provided with a bent anchor section, and each layer of reinforcing steel bars is tied with circumferential main bars, and the layers are connected by vertical main bars; The ring plate is welded on the top of the cylinder shell; The concrete cylinder uses the cylinder shell as the inner formwork, the bottom plate as the bottom formwork, the removable steel formwork as the outer formwork, and the upper ring plate as the top formwork. It is made by layered pouring and curing of UHPC concrete. The detachable steel template is composed of a plurality of sector-shaped cylindrical plates which are fastened and fixedly connected; The steel template is axially provided with multiple layers of casting holes; multiple casting holes are provided on each layer, and the multiple casting holes on the same layer are evenly arranged along the circumference of the steel template. After layered casting, a blocking plate is inserted into the inner side of the slot plate to block the casting holes; After the concrete cylinder is poured, a multi-layer cylindrical insulation layer is set on the outside of the steel formwork. The insulation layer is made of polystyrene board, polyurethane board or extruded board. Cure the UHPC concrete to the specified strength. During the curing period, the number of insulation layers can be dynamically adjusted according to the ambient temperature.

2. A UHPC spent fuel dry storage vertical container structure according to claim 1, characterized in that: Multiple annular stiffening ribs are evenly welded along the axial direction on the outer wall of the sector-shaped cylinder plate, and multiple vertical stiffening ribs are evenly arranged along the circumferential direction. The annular stiffening ribs and the vertical stiffening ribs form multiple force-bearing units to enhance the strength of the sector-shaped cylinder plate.

3. A vertical container structure for dry storage of UHPC spent fuel according to claim 2, characterized in that: The pouring hole needs to be set above the annular stiffening rib, and slot plates are welded on both sides of the pouring hole, and the bottom of the slot plate is fixedly connected to the annular stiffening rib.

4. A UHPC spent fuel dry storage vertical container structure according to claim 1, characterized in that: The cylinder shell includes a first cylindrical plate and a second cylindrical plate. The diameter of the first cylindrical plate is larger than that of the second cylindrical plate. A horizontal first ring plate is arranged between the first cylindrical plate and the second cylindrical plate to form a stepped structure.

5. The vertical container structure for dry storage of UHPC spent fuel according to claim 1, characterized in that: The top cover comprises a top cover shell with an opening at the top, and the base comprises a base shell with an opening at the top. Reinforced steel bars are welded inside the top cover shell or the base shell, and the shell is filled with UHPC concrete.

6. A vertical container structure for dry storage of UHPC spent fuel according to claim 5, characterized in that: A third ring plate is welded on the top of the side wall of the top cover shell, and the third ring plate covers the connection seam between the top cover and the cylinder shell.

7. The vertical container structure for dry storage of UHPC spent fuel according to claim 1, characterized in that: An air inlet is set at the bottom of the cylinder shell, and an air inlet is set at the top; the air inlet is welded to an air inlet steel pipe, and the exhaust port is welded to an exhaust steel pipe.

8. The method for constructing a vertical container structure for dry storage of UHPC spent fuel according to any one of claims 1 to 7, characterized in that: The specific steps are as follows: Prefabricate the bottom plate, cylinder shell, top cover shell, and base shell, and weld reinforcing steel bars on the cylinder shell, top cover shell, and base shell; prefabricate steel formwork and reserve casting holes; Install the bottom plate and weld and fix the cylinder shell, and tie the steel bars; then hoist, surround and fix the steel formwork outside the cylinder shell; UHPC concrete is poured layer by layer into the sealed cavity. After pouring, multiple layers of insulation are placed around the steel formwork. The top cover and base are poured simultaneously with the concrete cylinder, and the insulation layer is used to maintain the top cover and base. The UHPC concrete is cured to the specified strength, and the number of insulation layers can be adjusted dynamically according to the ambient temperature during the curing period. After curing, the insulation layer and steel formwork are removed; then the base is installed on the base plate, and finally the top cover is installed.

Images