UHPC spent fuel dry storage vertical container structure and construction method

Abstract

The invention discloses a UHPC spent fuel dry storage vertical container structure and a construction method, and belongs to the technical field of spent fuel dry storage. The cylinder shell is fixedly connected to the bottom plate; the concrete cylinder is arranged around the cylinder shell; the top cover is arranged at the upper parts of the concrete cylinder and the cylinder shell; the base is arranged on the bottom plate; a plurality of reinforcing steel bars are welded on the outer surface of the cylinder shell; an upper annular plate is welded to the top of the barrel shell. The concrete cylinder is formed by taking a cylinder shell as an inner mold, a bottom plate as a bottom mold, a steel template as an outer mold and an upper ring plate as a top mold through layered pouring and maintenance. The steel template can be detached, so that the construction quality and defects of the concrete cylinder can be conveniently detected, and the concrete cylinder can be subjected to nondestructive detection during in-service operation and maintenance; reinforcing steel bars are welded on the cylinder shell in advance, construction is convenient, the welding quality is guaranteed, by means of the high-strength performance and the high-binding-force characteristic of UHPC, the overall reinforcement amount is reduced, the cylinder wall thickness is reduced, and the site utilization rate is increased.

Description

Technical Field

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

[0002] The statements in this part only provide background technical information related to the present invention, and do not necessarily constitute prior art.

[0003] In nuclear power plants, spent fuel storage is divided into wet storage (pool storage) and dry storage; due to the large safety hazards of wet storage, dry storage is currently mostly recommended, that is, using special containers for storage. The vertical container for dry storage of spent fuel is generally a reinforced concrete container. In order to fully ensure the shielding performance of the container, the wall thickness of the reinforced concrete container is usually relatively thick, resulting in low site utilization.

[0004] A steel plate concrete structure module for dry storage of high burnup spent fuel disclosed in the prior art includes a top cover, a cylinder body and a base. The cylinder body adopts a concentrically arranged inner steel shell and outer steel shell. Studs are welded between the inner steel shell and the outer steel shell, and then concrete is poured to form a steel plate concrete structure. It can reduce the wall thickness of the container and improve the site utilization rate.

[0005] The following problems exist in using such a steel plate concrete container: The height of the container is relatively high. The two sides of the studs and stirrups are welded to the inner steel shell and the outer steel shell between the inner steel shell and the outer steel shell. The limited space makes the operation difficult and the welding quality cannot be guaranteed; only the top of the inner steel shell and the outer steel shell can be integrally poured, resulting in too thick a one-time feeding, incomplete vibration and affecting the compactness of the concrete, reducing the concrete strength; the concrete is enclosed by the outer steel shell, and the aging state of the internal concrete cannot be nondestructively detected (such as rebound method) through the outer steel shell during service. Summary of the Invention

[0006] In view of the above problems, the present invention provides a vertical container structure and construction method for dry storage of UHPC spent fuel. Taking 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, UHPC concrete is poured in layers and cured to make a concrete cylinder; the steel formwork can be disassembled, which is convenient for detecting the construction quality and defects of the concrete cylinder, and the concrete cylinder can be directly nondestructively detected during in-service operation and maintenance; reinforcing steel bars are welded in advance on the cylinder shell, which is convenient for construction and ensures the welding quality. With the high strength performance and high bonding force characteristics of UHPC concrete, the overall amount of reinforcement can be greatly reduced, the wall thickness of the cylinder can be reduced, and the site utilization rate can be improved; multiple pouring holes are provided in the steel formwork to avoid insufficient vibration caused by one-time feeding, resulting in reduced concrete strength, and at the same time avoid concrete segregation caused by too high feeding height, and ensure the strength of the cylinder.

[0007] To achieve the above object, the present invention adopts the following technical solutions: In a first aspect, a vertical container structure for dry storage of UHPC spent fuel is provided, comprising: 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; a ring plate is welded on the top of the cylinder shell; 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.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] 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.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] In a second aspect, a construction method for the vertical container structure of the above-mentioned UHPC spent fuel dry storage is provided, and the specific steps are as follows: Prefabricate the bottom plate, the cylindrical shell, as well as the top cover shell and the base shell. At the same time, weld reinforcing bars on the cylindrical shell, inside the top cover shell and the base shell; prefabricate steel formworks and reserve pouring holes; Install the bottom plate and weld and fix the cylindrical shell, and tie the reinforcing bars; then hoist, surround and fix the steel formworks on the outside of the cylindrical shell; Pour UHPC concrete into the sealed cavity in layers. After pouring is completed, surround multiple layers of thermal insulation layers on the outside of the steel formworks; while pouring the concrete cylinder, pour the top cover and the base, and use the thermal insulation layers to cure the top cover and the base; cure the UHPC concrete to the specified strength, and the number of layers of the thermal insulation layer can be dynamically adjusted according to the ambient temperature during the curing period; After curing is completed, remove the thermal insulation layers and the steel formworks; then install the base on the bottom plate, and finally install the top cover.

[0017] Compared with the prior art, the advantages and positive effects of the present invention are: In the present invention, the concrete cylinder uses the cylindrical 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, and is cured by pouring UHPC concrete in layers; the steel formwork can be disassembled, which is convenient for detecting the construction quality and defects of the concrete cylinder, and non-destructive testing (such as the rebound method) can be directly carried out on the concrete cylinder during the in-service operation and maintenance period; reinforcing bars are welded in advance on the cylindrical shell, which is convenient for construction and ensures the welding quality. With the high-strength performance and high bonding force characteristics of UHPC concrete, the overall amount of reinforcement can be greatly reduced, the wall thickness of the cylinder can be reduced, and the site utilization rate can be improved; multiple pouring holes are provided on the steel formwork to avoid insufficient vibration caused by one-time feeding, resulting in reduced concrete strength, and at the same time, to avoid concrete segregation caused by too high feeding height, and ensure the strength of the cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The attached drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0019] Figure 1 is a sectional view of the vertical container structure of Embodiment 1 or 2 of the present invention; Figure 2 is a sectional view of the vertical container structure and the steel formwork of Embodiment 1 or 2 of the present invention; Figure 3 is of the present invention Figure 1 the sectional view at A-A therein; Figure 4 is of the present invention Figure 2 the sectional view at B-B therein; Figure 5 is a sectional view of the top cover of Embodiment 1 or 2 of the present invention; Figure 6 is a sectional view of the base of Embodiment 1 or 2 of the present invention; Figure 7 is a sectional view of the cylindrical shell of Embodiment 1 or 2 of the present invention; Figure 8 is a partial steel bar layout diagram of the cylindrical shell of Embodiment 1 or 2 of the present invention; Figure 9 is a partial sectional view of the steel formwork of Embodiment 1 or 2 of the present invention; Figure 10 is the present invention Figure 4 an enlarged view of part C in; Figure 11 is a front view of the pouring hole of Embodiment 1 or 2 of the present invention; Figure 12 is a schematic diagram of the connection part of adjacent sector-shaped barrel plates of Embodiment 1 or 2 of the present invention; In the figure: 1, bottom plate; 2, cylindrical shell; 21, reinforcing steel bar; 22, first cylindrical plate; 23, first ring plate; 24, second cylindrical plate; 25, intake 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-shaped barrel plate; 62, annular stiffening rib; 63, vertical stiffening rib; 64, pouring hole; 65, clamping groove plate; 66, plugging plate; 67, heat insulation layer; 68, connecting plate. Detailed implementation manners

[0020] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0021] Glossary of terms: UHPC concrete: Ultra-high performance concrete, which has ultra-high durability and ultra-high mechanical properties.

[0022] The present invention will be described in detail below with reference to the accompanying drawings.

[0023] Embodiment 1 A UHPC dry storage vertical container structure for spent fuel disclosed in this embodiment is as shown in Figure 1As shown in the figure, it includes a bottom plate 1; a hollow cylindrical shell body 2 fixedly connected to the bottom plate 1, with an air inlet and an air outlet provided on the shell body 2; a concrete cylinder 3 arranged around the shell body 2; and a top cover 4 installed on the upper parts of the concrete cylinder 3 and the shell body 2, and a base 5 installed on the bottom plate 1.

[0024] As Figure 1 shown, the bottom plate 1 is a circular steel plate, the shell body 2 is a hollow steel cylinder, and the shell body 2 is located on the bottom plate 1. The two are connected by welding to form the main metal structure of the vertical container. The base 5, the top cover 4, and the shell body 2 jointly enclose an annular cavity for storing spent fuel; the fuel storage tank can be placed in the annular cavity.

[0025] As Figure 1 、 Figure 7 shown, several reinforcing bars 21 are welded on the outer surface of the shell body 2. The concrete cylinder 3 is cast with UHPC concrete. During casting, the UHPC concrete is connected to the reinforcing bars 21, so that the reinforcing bars 21 are combined with the concrete cylinder 3 to form an integral structure; at the same time, the shell body 2 is also connected to the concrete cylinder 3 as a whole, making the overall strength higher.

[0026] In this embodiment, the concrete cylinder 3 is cast in situ with UHPC concrete. UHPC concrete has extremely high durability and mechanical properties. With the high-strength performance and high bonding force characteristics of UHPC concrete, the overall amount of reinforcement can be greatly reduced, thereby reducing the thickness of the cylinder body of the concrete cylinder 3 and improving the site utilization rate.

[0027] In this embodiment, as Figure 1 、 Figure 2 、 Figure 4 、 Figure 7 shown, a ring plate 27 is welded on the top of the shell body 2 as the top formwork of the concrete cylinder 3. The shell body 2 is the inner formwork, the bottom plate 1 is the bottom formwork, and the detachable steel formwork 6 is the outer formwork. The concrete cylinder 3 is formed by casting and curing in a layered pouring manner. The advantages of setting the detachable outer formwork and layered pouring are that, since the shell body 2 is relatively high, the reinforcing bars 21 can be welded on the shell body 2 before installing the steel formwork 6; layered pouring can ensure that the concrete cylinder 3 has integrity and good performance.

[0028] As Figure 1 、 Figure 3 、 Figure 7 、 Figure 8 shown, the reinforcing bars 21 are horizontally arranged in several layers with equal layer spacing. The end far from the shell body 2 is provided with a bent anchor section, and the whole is in the shape of an umbrella handle. The circumferential main bars 29 are tied to each layer of the reinforcing bars 21, and the circumferential main bars 29 between layers are also tied to the reinforcing bars 21 with vertical main bars 28.

[0029] Because the height of the concrete cylinder 3 is relatively high, when the whole is poured, due to the excessive thickness of the single batch of materials, the vibration will be insufficient, which will affect the compactness of the concrete; at the same time, too high a feeding height will also cause the segregation of the concrete, resulting in a reduction in the strength of the cylinder body of the concrete cylinder 3.

[0030] Compared with the traditional steel plate concrete structure, in the method of entering the cavity between the inner steel shell and the outer steel shell after setting the inner and outer steel plates and welding the two ends of the stud or tie bar to the inner and outer steel shells, in this embodiment, before installing the steel formwork 6, the reinforcing bars 21 are welded to the cylinder shell 2, making the operation more convenient and further ensuring the welding quality.

[0031] Such as Figure 2 、 Figure 4 、 Figure 7 As shown, using the cylinder shell 2 as the inner formwork, the bottom plate 1 as the bottom formwork, the detachable steel formwork 6 as the outer formwork, and the upper ring plate 27 as the top formwork, a sealed cavity is formed, and UHPC concrete is filled in the sealed cavity. After the solidification and curing are completed, the steel formwork 6 is removed to form the concrete cylinder 3.

[0032] Due to the relatively high height of the concrete cylinder 3, it is necessary to adopt layered pouring. The steel formwork 6 can be removed after the curing of the concrete cylinder 3 and does not participate in the force-bearing of the concrete cylinder 3. In order to achieve layered pouring, as Figure 2 shown, multiple pouring holes 64 are arranged axially on the steel formwork 6, and UHPC concrete is poured into the sealed cavity between the cylinder shell 2, the bottom plate 1, the steel formwork 6, and the upper ring plate 27 through each pouring hole 64. In this embodiment, three layers of pouring holes 64 are provided, and the vertical spacing of the pouring holes 64 is the same.

[0033] Furthermore, as Figure 4 shown, each layer of pouring holes 64 is provided with multiple ones, and the multiple pouring holes 64 of the same layer are evenly arranged along the circumferential direction of the steel formwork. In this embodiment, the number of pouring holes 64 in each layer is eight. During pouring, pouring pipes are inserted into all eight pouring holes 64 of the same layer, and UHPC concrete is poured into the steel formwork 6 simultaneously, so that the UHPC concrete is evenly filled in the sealed cavity.

[0034] Even further, the steel formwork 6 is fixedly connected by buckling multiple sector-shaped cylinder plates 61; as Figure 2 、 Figure 4 、 Figure 9As shown, in order to ensure the strength of the steel formwork 6, a plurality of horizontal annular stiffeners 62 are uniformly welded along the axial direction on the outer wall of the sector barrel plate 61, and a plurality of vertical stiffeners 63 are uniformly arranged along the circumferential direction. The annular stiffeners 62 and the vertical stiffeners 63 form force-bearing units one by one, so as to strengthen the strength of the sector barrel plate 61 and resist the pressure generated in the sealed cavity when pouring UHPC concrete.

[0035] In this embodiment, there are two sector barrel plates 61.

[0036] Furthermore, as Figure 12 shown, in order to ensure the stable connection between the sector barrel plates 61, a connecting plate 68 is provided on one side of the barrel wall of the sector barrel plate 61, and not on the other side; on the side of the connecting plate 68 of the sector barrel plate 61, it is connected to the side of the adjacent sector barrel plate 61 without the connecting plate 68, and several fasteners are used for connection at the connection. In this embodiment, bolts are used for connection.

[0037] Furthermore, as Figure 2 、 Figure 4 、 Figure 9 、 Figure 10 、 Figure 11 shown, the pouring hole 64 needs to be arranged above the annular stiffener 62, and clamping groove plates 65 are fixedly welded on both sides of the pouring hole 64. The bottom of the clamping groove plate 65 is fixedly connected to the annular stiffener 62; one of the functions of the clamping groove plate 65 is to limit the left and right shaking of the pouring pipe, and the second function is to draw out the pouring pipe after the pouring of this layer is completed, insert a plugging plate 66 into the clamping groove plate 65, and plug the pouring hole 64 together with the plugging plate 66. The height of the plugging plate 66 is greater than the diameter of the pouring hole 64.

[0038] Optimally, the top of the steel formwork 6 is higher than the upper ring plate 27, and at the same time, auxiliary pouring holes (not shown in the figure) are also opened at the outer edge of the upper ring plate 27 (i.e., the edge away from the cylinder shell 2), and the uppermost layer of UHPC concrete is poured from top to bottom to ensure that the UHPC concrete fills the sealed cavity.

[0039] As Figure 2 、 Figure 4 、 Figure 9 shown, after the pouring of the concrete cylinder 3 is completed, heat preservation and curing are required. A plurality of layers of cylindrical heat preservation layers 67 are arranged on the outside of the steel formwork 6. The heat preservation layer 67 is made of polystyrene board or polyurethane board or extruded board, and these materials have good heat preservation performance and compressive performance.

[0040] In this embodiment, three layers of thermal insulation layers 67 are provided, and the number of layers of the thermal insulation layer 67 is set according to the temperature difference between the ambient temperature and the curing target temperature. It should be noted that the number of layers of the thermal insulation layer 67 can be dynamically adjusted according to the ambient temperature during curing. For example, when the temperature decreases, the number of layers of the thermal insulation layer 67 is increased, and when the temperature rises, the number of layers of the thermal insulation layer 67 is decreased.

[0041] As Figure 1 shown, the top cover 4 is connected to the cylindrical shell 2 and the concrete cylinder 3 by a stepped structure. Specifically, as Figure 7 shown, the cylindrical shell 2 includes a first cylindrical plate 22, a first ring plate 23 and a second cylindrical plate 24. The first cylindrical plate 22 and the second cylindrical plate 24 are concentrically arranged, 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 respectively welded to the upper and lower surfaces of the first ring plate 23 to form a stepped structure for mating connection with the top cover 4. The upper ring plate 27 is welded to the top of the first cylindrical plate 22 as the top form of the concrete cylinder 3 and is also used to cooperate with the top cover 4 to seal the connection seam between the cylindrical shell 2 and the cylindrical shell 2.

[0042] As Figure 5 shown, the top cover 4 includes a top cover shell 41. Reinforcing bars 21 are also welded inside the top cover shell 41. The reinforcing bars 21 are vertically arranged inside the top cover 4. At the same time, horizontal main bars and circumferential main bars are also provided. The top cover shell 41 is filled with UHPC concrete.

[0043] 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 that 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 for mating with the cylindrical shell 2.

[0044] It should be noted that the outer diameter of the fourth cylindrical plate 43 is equal to the inner diameter of the first cylindrical plate 22, so that the outer wall of the top cover 4 is closely attached to the inner wall of the cylindrical shell 2.

[0045] As Figure 5 shown, the first circular plate 46 is welded to the bottom of the third cylindrical plate 42. The third cylindrical plate 42, the fourth cylindrical plate 43, the second ring plate 44 and the first circular plate 46 form the top cover shell 41. Reinforcing bars are welded inside the top cover shell 41 and UHPC concrete is filled to form the top cover 4.

[0046] As Figure 5As shown in the figure, to enhance the sealing performance, the third ring plate 45 is welded to the top of the fourth cylinder plate 43. The third ring plate 45 is used to cover the connection seam between the top cover 4 and the cylinder shell 2 to prevent the leakage of radioactive substances. In some embodiments, a steel plate is provided between the third ring plate 45 and the upper ring plate 27 to further enhance the sealing performance between the top cover 4 and the cylinder shell 2.

[0047] As Figure 6 shown, the base 5 includes a base shell, and reinforcing bars 21 are welded inside the base shell. The reinforcing bars 21 are vertically arranged inside the base 5. At the same time, horizontal main bars and circumferential main bars are also provided, and the base shell is also filled with UHPC concrete. The base shell includes a second circular plate 51, and a fifth cylinder plate 52 is welded circumferentially to the second circular plate 51. The reinforcing bars 21 are welded to the second circular plate 51, and then UHPC concrete is filled inside the second circular plate 51 and the fifth cylinder plate 52 to form the base 5. A fuel storage tank is placed on the base 5.

[0048] As Figure 1 shown, the diameter of the fifth cylinder plate 52 is smaller than the diameter of the cylinder shell 2 by a set distance, forming a certain gap between the base 5 and the cylinder shell 2, which is used to guide a part of the radioactive particles to leak into this gap, reducing the leakage to the external environment.

[0049] As Figure 1 、 Figure 7 shown, an air inlet is provided at the bottom of the cylinder shell 2, and an air outlet is provided at the top; an intake steel pipe 25 is welded to the air inlet, and an exhaust steel pipe 26 is welded to the air outlet. Both the intake steel pipe 25 and the exhaust steel pipe 26 are horizontally arranged, and the ends of the intake steel pipe 25 and the exhaust steel pipe 26 far from the cylinder shell 2 extend to the outer wall of the concrete cylinder 3 (i.e., the inner wall of the steel formwork 6).

[0050] As Figure 1 shown, the annular cavity is communicated with the external atmosphere through the intake steel pipe 25 and the exhaust steel pipe 26, thereby forming a passive natural convection channel flowing axially along the annular cavity between the inner wall of the cylinder shell 2 and the outer surface of the spent fuel sealed container. The air inlet is opened at a set distance from the bottom of the top surface of the base 5, and the air outlet is opened at a set distance from the bottom of the first ring plate 23; effectively reducing the air flow resistance and improving the waste heat discharge capacity.

[0051] In this embodiment, the base 5 and the top cover 4 can be prefabricated in advance; after the concrete cylinder 3 is cured, hoisting is carried out; it can be understood that lifting holes or lifting rings can be reserved in advance on the steel structure shells of the base 5 and the top cover 4.

[0052] It can also be constructed on-site, 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.

[0053] Further, a centering hole is reserved at the center of the bottom of the base housing of the base 5, a centering hole steel pipe is welded and fixed on the centering hole, at least one limiting hole is reserved at the remaining positions of the bottom of the base housing, and a limiting hole steel pipe is welded and fixed on the limiting hole; at the same time, a centering pin shaft is welded and fixed in advance at the center of the bottom plate 1, and a limiting pin shaft is welded and fixed at the corresponding position, so that the base housing of the base 5 can be positioned and limited on the bottom plate 1. Whether the base 5 is cast in place first and then the concrete cylinder 3 is poured, or the base 5 is prefabricated first and then installed on the bottom plate 1, the base 5 can be positioned and limited.

[0054] In this embodiment, the concrete cylinder 3 made with the cylinder housing 2 as the inner mold has a better connection and seal with the top cover 4 compared with the traditional reinforced concrete structure, and the cylinder thickness is lower; compared with the steel plate concrete structure, there is no steel plate seal on the outside of the concrete cylinder 3, which is convenient for detecting the construction quality and defects of UHPC concrete, and can also directly perform non-destructive testing on the concrete cylinder 3 during in-service operation and maintenance. In addition, during the construction stage, reinforcing steel bars can be welded on the cylinder housing 2 in advance, the construction is more convenient, and the welding quality is easy to guarantee; and it can achieve layered pouring, avoiding insufficient vibration caused by one-time feeding, resulting in reduced concrete strength, and avoiding concrete segregation caused by too high feeding height, ensuring the strength of the cylinder.

[0055] Embodiment 2 A construction method of a UHPC spent fuel dry storage vertical container structure provided in this embodiment uses a UHPC spent fuel dry storage vertical container structure disclosed in Embodiment 1, and the specific steps are as follows: Prefabricate the bottom plate, cylinder housing, as well as the top cover housing and base housing, and at the same time weld reinforcing steel bars in the cylinder housing, top cover housing, and base housing; prefabricate the steel formwork 6, reserve a pouring hole, and weld the clamping groove plate; by prefabricating each steel component, the construction period can be saved.

[0056] Install the bottom plate on site and weld and fix the cylinder housing, and then tie the steel bars on the reinforcing steel bars; since there are no other components outside the cylinder housing, it is more convenient to tie the steel bars on the reinforcing steel bars.

[0057] Then, hoist, surround, and fix the steel formwork 6 outside the cylinder housing to prepare for pouring; Pour UHPC concrete into the sealed cavity in layers. After pouring is completed, surround multiple layers of thermal insulation layers 67 outside the steel formwork 6; while pouring the concrete cylinder 3, pour the top cover 4 and the base 5, and use the thermal insulation layer 67 to cure the top cover 4 and the base 5; cure the UHPC concrete to the specified strength, and the number of layers of the thermal insulation layer 67 can be dynamically adjusted according to the ambient temperature during the curing period.

[0058] For example, when the temperature drops, increase the number of layers of the thermal insulation layer 67, and when the temperature rises, reduce the number of layers of the thermal insulation layer 67.

[0059] After the curing is completed, remove the thermal insulation layer and the steel formwork outside the concrete cylinder 3, and remove the thermal insulation layer outside the top cover 4 and the base 5; then install the base 5 on the bottom plate 1. When installing, insert the centering pin shaft and the limit pin shaft of the bottom plate 1 into the centering hole and the limit hole at the bottom of the base 5; finally, install the top cover 4.

[0060] Pouring the top cover 4 and the base 5 while pouring the concrete cylinder 3 can not only save the construction period; but also enable the concrete cylinder 3, the top cover 4 and the base 5 to adopt the same period of concrete, ensure the same strength, and at the same time ensure the same curing conditions (the ambient temperature and the curing days during the same period of pouring).

[0061] Although the specific implementation manners of the present invention are described above in conjunction with the accompanying drawings, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that, based on the technical solution of the present invention, various modifications or deformations that can be made by those skilled in the art without creative labor are still within the protection scope of the present invention.

Claims

1. A vertical container structure for dry storage of UHPC spent fuel, characterized in that, Comprising: Bottom plate; A hollow cylindrical barrel housing is fixedly connected to the bottom plate; a concrete barrel is arranged around the barrel housing; And a top cover installed on the upper parts of the concrete barrel and the barrel housing, and a base installed on the bottom plate; Several reinforcing bars are welded on the outer surface of the barrel housing; an upper ring plate is welded on the top of the barrel housing; The concrete barrel is cured by pouring UHPC concrete in layers with the barrel housing 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.

2. The vertical container structure for dry storage of UHPC spent fuel as described in claim 1, wherein The steel formwork is axially provided with multiple layers of pouring holes; multiple pouring holes are arranged in each layer, and the multiple pouring holes in the same layer are evenly arranged along the circumferential direction of the steel formwork.

3. The vertical container structure for dry storage of UHPC spent fuel as described in claim 1, characterized in that, The steel formwork is fixedly connected by buckling multiple sector barrel plates; multiple circumferential stiffening ribs are evenly welded on the outer wall of the sector barrel plate along the axial direction, and multiple vertical stiffening ribs are evenly arranged along the circumferential direction. The circumferential stiffening ribs and the vertical stiffening ribs form multiple stress units to strengthen the strength of the sector barrel plate.

4. The vertical container structure for dry storage of UHPC spent fuel as described in claim 3, characterized in that, The pouring holes need to be arranged above the circumferential stiffening ribs, and clamping groove plates are welded on both sides of the pouring holes. The bottom of the clamping groove plate is fixedly connected to the circumferential stiffening rib; after pouring in layers, a plugging plate is inserted into the inner side of the clamping groove plate to plug the pouring holes.

5. The vertical container structure for dry storage of UHPC spent fuel as described in claim 1, characterized in that, After the concrete barrel is poured, multiple layers of cylindrical heat preservation layers are arranged outside the steel formwork. The heat preservation layer is made of polystyrene board or polyurethane board or extruded board.

6. The vertical container structure for dry storage of UHPC spent fuel according to claim 1, characterized in that, The barrel housing 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.

7. A vertical container structure for dry storage of UHPC spent fuel as described in claim 1, characterized in that, The top cover includes a top cover housing with an opening at the top, and the base includes a base housing with an opening at the top. Reinforcing bars are welded in the top cover housing or the base housing and filled with UHPC concrete.

8. The vertical container structure for dry storage of UHPC spent fuel as described in claim 7, characterized in that, A third ring plate is welded on the top of the side wall of the top cover housing, and the third ring plate covers the connection seam between the top cover and the barrel housing.

9. The vertical container structure for dry storage of UHPC spent fuel as described in claim 1, characterized in that, An air inlet is arranged at the bottom of the barrel housing, and an air outlet is arranged at the top; an air inlet steel pipe is welded to the air inlet, and an air outlet steel pipe is welded to the air outlet.

10. A construction method for a vertical container structure for dry storage of UHPC spent fuel according to any one of claims 1-9, characterized in that, The specific steps are as follows: Prefabricate the bottom plate, the barrel housing, as well as the top cover housing and the base housing, and at the same time, weld reinforcing bars in the barrel housing, the top cover housing and the base housing; prefabricate the steel formwork and reserve pouring holes; Install the bottom plate and weld and fix the barrel housing, tie the steel bars; then hoist, surround and fix the steel formwork outside the barrel housing; Pour UHPC concrete into the sealed cavity in layers. After pouring is completed, surround multiple layers of heat preservation layers outside the steel formwork; while pouring the concrete barrel, pour the top cover and the base, and use the heat preservation layer to cure the top cover and the base; cure the UHPC concrete to the specified strength, and the number of layers of the heat preservation layer can be dynamically adjusted according to the ambient temperature during the curing period; After curing is completed, remove the heat preservation layer and the steel formwork; then install the base on the bottom plate, and finally install the top cover.

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