Passive high-level super-large pressure tank for nuclear power plant and manufacturing method thereof based on rigid-flexible coordination concept

Abstract

This invention relates to the field of nuclear power, and more particularly to a passive, high-level, ultra-large pressurized water tank for nuclear power plants based on the concept of rigid-flexible coordination, and its manufacturing method. The tank includes: a pressure-bearing boundary and equipment supports; the pressure-bearing boundary is spherical, constructed by welding together spherical shell plates; the equipment supports include external and internal supports, connected and transferring loads via a middle reinforcing ring, an upper reinforcing ring, and a lower reinforcing ring within the pressure-bearing boundary; the internal supports are steel structures, welded together as a whole; the external supports include supports, upper tie rods, and lower tie rods, with one end of the upper tie rod connected to the upper reinforcing ring, and multiple upper tie rods evenly distributed on the upper reinforcing ring; one end of the lower tie rod is connected to the lower reinforcing ring, and multiple lower tie rods evenly distributed on the lower reinforcing ring; multiple supports are evenly distributed on the middle reinforcing ring. This invention has good rationality and feasibility, and can meet the construction requirements of large pressurized water tanks in nuclear power plants.

Description

Technical Field

[0001] This invention relates to the field of nuclear power, and in particular to a passive, high-level, ultra-large pressurized water tank for nuclear power plants based on the concept of rigid-flexible coordination, and its manufacturing method. Background Technology

[0002] Third-generation pressurized water reactor nuclear power plants mostly adopt a safety design concept that combines active and passive safety mechanisms. Active safety systems rely on external triggers and power sources, such as electricity or compressed air, to execute safety functions. Passive safety systems, on the other hand, do not rely on external triggers or power sources to perform safety functions; instead, they rely on natural convection, gravity, and pressure potential. Active and passive systems can complement each other, allowing for diverse designs to avoid common-cause failures and improving the overall safety of the power plant at a relatively low cost. Passive safety design is the most important design feature of third-generation nuclear power. Internationally mainstream third-generation nuclear power models, such as AP1000, VVER, and APR1400, all employ passive safety technologies. Current domestic third-generation nuclear power safety designs adopt an active + passive approach, meaning that effective passive safety measures are implemented on top of active safety systems. The passive safety system serves as a supplement to the active safety system; it is activated when the active safety system fails, and it does not need to respond to design-baseline accidents. According to this concept, active and passive safety systems are considered safety-level systems. Active safety systems also need to consider redundancy and are equipped with a large number of safety-level support systems, resulting in a complex overall safety system configuration and high engineering costs. On the other hand, the cooling water source for the active safety system is located inside the containment vessel, increasing the size of the containment vessel and also increasing the overall layout difficulty of the nuclear island.

[0003] To further enhance unit operational safety and reduce engineering costs for mass construction, a passive-active + active approach is adopted based on existing active + passive safety technologies. The passive system serves as a dedicated safety facility to address design-baseline accidents, while the active system acts as a backup in case of passive system failure, capable of handling extended design conditions. Replacing the active system with the passive system as a dedicated safety facility offers significant economic advantages, eliminating the need for numerous safety-grade support systems. Furthermore, the active system serving as a design-extended condition response facility can be non-safety-grade and non-redundant, simplifying the system and significantly contributing to reduced power plant costs. Using the passive system as a dedicated safety facility requires addressing design-baseline accidents; therefore, large-capacity, high-level cooling water storage equipment is essential. Simultaneously, the engineering economics of the water storage equipment must be fully considered to meet the overall requirements of mass construction of third-generation nuclear power water reactors.

[0004] Based on the aforementioned passive + active design concept, further design requirements are proposed for the water storage equipment in the safety system, mainly including:

[0005] First, it is essential to provide a massive cooling water source capable of meeting the needs of the passive core cooling system to ensure reliable cooling of the reactor core under accident conditions. Under accident conditions, the reactor core requires thousands of cubic meters of water for cooling. The Westinghouse AP1000 uses a passive core cooling water source integrated into the containment vessel with a capacity of 2132 m³. 3 In the current design, in order to further improve the economic efficiency of nuclear power plants, the passive core cooling water source needs to be placed outside the containment to reduce the containment volume. At the same time, in order to meet the cooling requirements of the passive core, the capacity needs to be increased to more than twice that of AP1000. Therefore, the design and construction difficulty has increased for the pressurized water tank for water storage and its own support structure, plant structure support, etc.

[0006] Secondly, the pressurized water tank in the passive core cooling system must withstand the high temperature and pressure of the containment under accident conditions. The current design places the water tank outside the containment. During passive water injection, it is necessary to maintain communication between the water tank and the interior of the containment. Under accident conditions, the pressurized water tank will be subjected to high temperature (above 150°C) and internal high pressure (approximately 0.55 MPa) simultaneously with the containment. The internal pressure will limit the structure and shape of the ultra-large water tank, making it impossible to use the traditional concrete structure with stainless steel lining on the inner wall. The current design scheme is to use a pressurized water tank made of pure stainless steel. It is necessary to consider the pressure on the equipment and the high temperature thermal expansion caused by the steel structure to form a new pressurized water tank.

[0007] Third, the pressurized water tank, which serves as the water storage source, is a critical dedicated safety facility with high seismic resistance requirements. The pressurized water tank, which provides the water source in the safety system, is a critical dedicated safety facility, classified as a Level 1 safety function item, a Level 2 barrier item, and a Class II seismic resistance item. This means the equipment must be able to withstand loads caused by the ultimate safe seismic motion and must maintain its integrity or airtightness during an earthquake.

[0008] Existing technologies, such as the water tanks of the AP1000's built-in core cooling system, all adopt a concrete structure with stainless steel lining on the inner wall. When performing seismic calculations, the conventional seismic calculations can be performed on the plant structure, taking into account the fluid-structure interaction between the water in the pressurized water tank and the concrete structure. The design and calculation methods are relatively mature and less difficult.

[0009] The current proposed design scheme requires raising the position of the passive containment heat dissipation system and the pressurized water tank supporting its main equipment to meet the design requirements for high-level injection of the passive + active safety system (the bottom of the water tank should be more than 20 meters high).

[0010] Based on a safety design concept combining passive and active systems, the passive water tanks providing cooling water in the safety injection system are required to be extremely large, with a total weight (over 3000 tons) when full, and located high within the plant building. They must also be able to withstand thermal expansion. According to the seismic design standards for third-generation nuclear power plants, large equipment must be designed in conjunction with the plant structure; therefore, the pressurized water tanks also require coupling and adaptation with the plant structure design. Furthermore, the pressurized water tanks must be designed with their own supporting structures. This means the tank support system includes not only its own support structure but also the plant structure. The overall design cannot simply consider the equipment tank, equipment support structure, and plant structure separately; instead, it must comprehensively address the contradictions in the technical design based on the actual engineering situation. Currently, there are no mature technologies or design methods available for reference. The engineering implementation of the high-level, ultra-large water tanks and their structural support systems in the safety injection system is extremely challenging. Summary of the Invention

[0011] The technical problem to be solved by this invention is to provide a passive high-level ultra-large pressurized water tank for nuclear power plants based on the concept of rigid-flexible coordination and its manufacturing method, which has good rationality and feasibility and can meet the construction requirements of large pressurized water tanks in nuclear power plants.

[0012] This invention provides a passive, high-level, ultra-large pressurized water tank for nuclear power plants based on the concept of rigid-flexible coordination, including: a pressure-bearing boundary and equipment support;

[0013] The pressure-bearing boundary is spherical and is made of spherical shell plates welded together, including a middle reinforcing ring, an upper reinforcing ring, a lower reinforcing ring, and other conventional spherical shell plates;

[0014] The equipment support includes external support and internal support. The external support and internal support are connected and transfer load through the middle reinforcing ring, upper reinforcing ring and lower reinforcing ring in the pressure boundary.

[0015] The internal support is a steel structure, welded together from steel, including multiple layers of outer circumferential supports, multiple arc-shaped supports, multiple radial supports, multiple inner circumferential supports, and multiple vertical supports;

[0016] The external support includes a support, an upper tie rod, and a lower tie rod. One end of the upper tie rod is connected to the upper reinforcing ring, and multiple upper tie rods are evenly distributed on the upper reinforcing ring.

[0017] One end of the lower tie rod is connected to the lower reinforcing ring, and multiple lower tie rods are evenly distributed on the lower reinforcing ring;

[0018] Multiple supports are evenly distributed on the central reinforcing ring.

[0019] In one specific embodiment of the present invention, the outer circumferential support consists of three layers, including an upper outer circumferential support, a middle outer circumferential support, and a lower outer circumferential support. There are 20 arc-shaped supports, 30 radial supports, 3 layers of inner ring supports, and 40 vertical supports.

[0020] In one specific embodiment of the present invention, the upper outer circumferential support, the middle outer circumferential support and the lower outer circumferential support are respectively welded to the inner sides of the upper reinforcing ring, the middle reinforcing ring and the lower reinforcing ring, and the arc-shaped support is respectively welded to other spherical shell plates of the pressure-bearing boundary.

[0021] In one specific embodiment of the present invention, the support is connected to the internal support and transmits load through the middle reinforcing ring, the upper tie rod is connected to the internal support through the upper reinforcing ring and transmits load, and the lower tie rod is connected to the internal support and transmits load through the lower reinforcing ring.

[0022] In one specific embodiment of the present invention, the support is provided with multiple through anchor bolt holes on the top and bottom for anchor bolts to pass through.

[0023] In one specific embodiment of the present invention, the spherical shell plate includes an upper temperate plate, a lower temperate plate, an upper electrode plate, and a lower electrode plate;

[0024] The upper electrode plate includes: upper middle plate, upper side plate, and upper edge plate, which are welded together to form the arc-shaped top of the water tank;

[0025] The lower electrode plate includes: the lower electrode middle plate, the lower electrode side plate, and the lower electrode edge plate. The three are welded together to form the arc-shaped bottom of the water tank.

[0026] Several upper temperate zone plates are arranged in an arc shape and positioned between the upper reinforcing ring and the middle reinforcing ring;

[0027] Several lower temperate zone plates are arranged in an arc shape and positioned between the lower reinforcing ring and the middle reinforcing ring.

[0028] This invention provides a method for manufacturing a passive, high-level, ultra-large pressurized water tank for nuclear power plants based on the concept of rigid-flexible coordination, comprising the following steps:

[0029] Step 1: Weld the support and the central reinforcing ring together to prefabricate the central reinforcing ring support assembly, and transport all modular components to the assembly construction site;

[0030] Step 2: Hoist each auxiliary support component into the precast foundation surface and assemble them into a whole, connecting them to form a support frame;

[0031] Step 3: Hoist the reinforcing ring support assembly onto the auxiliary support assembly to form the support structure of the passive shell external pressure tank;

[0032] Step 4: Weld the temperate zone plate and the lower temperate zone plate to both sides of the middle reinforcing ring respectively;

[0033] Step 5: Assemble the upper and lower reinforcing rings and weld them to the upper and lower tempering plates respectively;

[0034] Step 6: Position the internal support and weld it to the middle reinforcing ring, upper warm zone plate, lower warm zone plate, and upper and lower reinforcing rings;

[0035] Step 7: Assemble and weld the upper electrode plate to the upper reinforcing ring, and assemble and weld the lower electrode plate to the lower reinforcing ring;

[0036] Step 8: Weld the upper tie rod and the lower tie rod to the upper reinforcing ring and the lower reinforcing ring respectively;

[0037] Step 9: Weld the connecting pipe assemblies in the upper and lower electrode plates.

[0038] In one specific embodiment of the present invention, the intermediate reinforcing ring is assembled from multiple modular intermediate reinforcing ring plates;

[0039] The upper reinforcing ring is assembled from multiple modular upper reinforcing ring plates;

[0040] The lower reinforcing ring is assembled from multiple modular lower reinforcing ring plates.

[0041] In one specific embodiment of the present invention, the auxiliary support assembly includes: a support plate, a support column, a support tie rod, and a support base plate;

[0042] The upper end of the support column is connected to the support plate, and the lower end is connected to the support base plate;

[0043] The tie rods connect adjacent support columns to form a frame structure;

[0044] The support rod has an adjustment function.

[0045] In one specific embodiment of the present invention, the auxiliary support assembly includes 20 support columns, 20 support plates and 20 support base plates, as well as support rods connecting the support columns;

[0046] The horizontal deviation of the upper surface of the 20 upper support plates shall not exceed 3 mm;

[0047] The support plate supports the bracket.

[0048] In a specific embodiment of the present invention, in step 3, multiple modular intermediate reinforcing ring support assemblies are hoisted onto the auxiliary support assembly to provide support for the support; each intermediate reinforcing ring and the auxiliary support assembly are adjusted and positioned and then fixedly welded, and positioned by temporary fixing clamps to prevent deformation.

[0049] In one specific embodiment of the present invention, step 4 specifically includes:

[0050] Multiple upper and lower tempering plates are tack welded to the middle reinforcing ring and positioned using temporary fixing clamps;

[0051] Remove the temporary fixing clamps, and weld the multiple upper and lower temperate zone plates to the central reinforcing ring in full dimensions. After welding, perform non-destructive testing according to the construction drawings.

[0052] In one specific embodiment of the present invention, step 5 specifically includes:

[0053] Multiple modular upper reinforcing ring plates are assembled into an upper reinforcing ring, which is then positioned and welded to the upper tempering plate using a temporary fixing clamp.

[0054] Multiple modular lower reinforcing plates are assembled into a lower reinforcing ring, which is then tack welded to the lower temperate zone plate and positioned using a temporary fixing clamp.

[0055] Remove the fixing clamps, weld the upper reinforcing ring to the upper tempering plate to full dimensions, and perform non-destructive testing according to the construction drawings after welding;

[0056] The lower reinforcing ring is welded to the lower tempered zone plate in full dimensions, and non-destructive testing is performed according to the construction drawings after welding.

[0057] In one specific embodiment of the present invention, step 6 specifically includes:

[0058] The upper outer circumferential support, the middle outer circumferential support, and the lower outer circumferential support are respectively assembled and welded to the upper reinforcing ring, the middle reinforcing ring, and the lower reinforcing ring.

[0059] Multiple radial supports are radially welded to the outer circumferential support of the upper part, and an inner circumferential support of the upper layer is welded to the other end of the radial supports.

[0060] Multiple radial supports are radially welded to the outer circumferential support in the middle section, and an inner circumferential support of the middle layer is welded to the other end of the radial supports.

[0061] Multiple radial supports are radially welded to the lower outer circumferential support, and an inner circumferential support of the lower layer is welded to the other end of the radial support.

[0062] The lower side of the upper outer circumferential support is welded to multiple vertical supports, which are simultaneously welded to a radial support connecting the middle outer circumferential support and an inner circumferential support of the middle layer. The upper side of the lower outer circumferential support is welded to multiple vertical supports, which are simultaneously welded to a radial support connecting the middle outer circumferential support and an inner circumferential support of the middle layer.

[0063] In a specific embodiment of the present invention, step 7 specifically includes:

[0064] The upper and lower electrode side plates are assembled with the upper and lower reinforcing rings respectively. The upper electrode side plate, lower electrode side plate, upper electrode middle plate, and lower electrode middle plate are assembled in sequence and then welded. After welding, non-destructive testing is performed according to the drawing requirements.

[0065] Compared with the prior art, the passive high-level ultra-large pressurized water tank for nuclear power plants based on the concept of rigid-flexible coordination and its manufacturing method have the following beneficial effects:

[0066] (1) The ultra-large pressurized water tank structure provided by the present invention adopts the concept of rigid-flexible coordination, including the pressure-bearing boundary and equipment support. The pressure-bearing boundary adopts a spherical shape with good stress, and upper reinforcing ring, middle reinforcing ring and lower reinforcing ring are set in the upper, middle and lower support parts to improve the strength of the equipment. The equipment support has internal support and external support. The internal support forms a frame structure and is welded to the pressure-bearing boundary to enhance the overall strength and rigidity of the pressure-bearing boundary. The external support adopts a flexible support with a movable structure, which can bear the load of self-weight, internal pressure, earthquake and other working conditions, and can also solve the influence of thermal expansion load.

[0067] The rigid-flexible coordination concept adopted in this invention can effectively solve the structural design difficulties caused by the large weight and high seismic resistance requirements of high-level ultra-large pressurized water tanks in nuclear power plants. It is of great significance for promoting the development and implementation of passive technologies for pressurized water reactor nuclear power plants.

[0068] (2) The present invention changes the manufacturing of ultra-large pressurized water tanks from the traditional fixed assembly to modular prefabrication. The manufacturing method involves assembling the tanks in a temporary factory and then hoisting them into place. This includes prefabricating each modular component in the factory, adding auxiliary support components, placing them on the prefabricated foundation surface, forming a support structure with the support components, and then assembling the upper and lower temperature zone plates, upper and lower reinforcing rings, internal supports, upper and lower edge plates, upper and lower tie rods, and pipe assembly in this way.

[0069] This invention adopts a modular prefabrication and assembly method, which solves the problems of high placement, limited space, and poor construction conditions. It features good construction conditions, complete construction tools, and high positioning accuracy in temporary factory buildings, and improves safety during construction.

[0070] This invention employs a manufacturing method that involves assembling and then hoisting the passive outer shell pressurized water tank into place. The assembly of the tank is completed within a temporary workshop, and the equipment assembly and nuclear island placement are carried out independently within the temporary workshop. This significantly saves on-site construction time and effectively improves the construction progress. Attached Figure Description

[0071] Figure 1This is a schematic diagram of the overall structure of a passive shell external pressure-bearing water tank according to an embodiment of the present invention;

[0072] Figure 2 This is a three-dimensional schematic diagram of a passive external pressure water tank according to an embodiment of the present invention.

[0073] Figure 3 This is a schematic diagram of an auxiliary support component in one embodiment of the present invention;

[0074] Figure 4 This is a schematic diagram of the support structure in one embodiment of the present invention;

[0075] Figure 5 This is a schematic diagram of the connection of a portion of the water tank body in one embodiment of the present invention;

[0076] Figure 6 This is a schematic diagram of the internal support structure in one embodiment of the present invention;

[0077] Figure 7 This is a structural diagram of the internal support in one embodiment of the present invention;

[0078] Figure 8 This is a BB cross-sectional schematic diagram of the internal support component structure in one embodiment of the present invention;

[0079] Figure 9 This is a schematic diagram of the upper and lower electrode plates in one embodiment of the present invention;

[0080] Figure 10 This is a schematic diagram of the structure of a temporary fixing frame in one embodiment of the present invention;

[0081] In the diagram: 10-Spherical shell plate, 101-Upper temperate zone plate, 102-Lower temperate zone plate, 103-Upper pole middle plate, 104-Upper pole side plate, 105-Upper pole edge plate, 106-Lower pole middle plate, 107-Lower pole side plate, 108-Lower pole edge plate, 20-Middle reinforcing ring support assembly, 201-Support, 202-Middle reinforcing ring, 30-Upper and lower reinforcing ring assembly, 301-Upper reinforcing ring, 302-Lower reinforcing ring, 40-Internal support, 40 1-Upper outer circumferential support, 402-Middle outer circumferential support, 403-Lower outer circumferential support, 404-Arc-shaped support, 405-Radial support, 406-Inner annular support, 407-Vertical support, 50-Auxiliary support assembly, 501-Support plate, 502-Support column, 503-Support tie rod, 504-Support base plate, 505-Fixing clamp, 60-Upper tie rod, 70-Lower tie rod, 80-Connecting pipe assembly. Detailed Implementation

[0082] To further understand the present invention, embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the present invention.

[0083] Embodiments of the present invention disclose a passive, high-level, ultra-large pressurized water tank for nuclear power plants based on the concept of rigid-flexible coordination, such as... Figures 1-2 As shown, it includes: pressure-bearing boundaries and equipment supports;

[0084] The pressure-bearing boundary is spherical and is made of spherical shell plates welded together, including a middle reinforcing ring 202, an upper reinforcing ring 301, a lower reinforcing ring 302, and other conventional spherical shell plates 10;

[0085] The spherical shell plate 10 includes an upper temperate plate 101, a lower temperate plate 102, an upper electrode plate, and a lower electrode plate;

[0086] like Figure 9 As shown, the upper electrode plate includes: upper middle plate 103, upper side plate 104, and upper edge plate 105, which are welded together to form the arc-shaped top of the water tank.

[0087] The lower electrode plate includes: a lower electrode middle plate 106, a lower electrode side plate 107, and a lower electrode edge plate 108, which are welded together to form the arc-shaped bottom of the water tank;

[0088] Several upper temperate zone plates 101 are arranged in an arc shape and positioned between the upper reinforcing ring 301 and the middle reinforcing ring 202;

[0089] Several lower temperate zone plates 102 are arranged in an arc shape and positioned between the lower reinforcing ring 302 and the middle reinforcing ring 20.

[0090] The various parts are connected by welding. The pressure-bearing boundary is used to withstand the internal loads generated by the internal pressure.

[0091] The equipment support includes external support and internal support 40. The external support and internal support 40 are connected and transfer load through the middle reinforcing ring 202, upper reinforcing ring 301 and lower reinforcing ring 302 in the pressure-bearing boundary.

[0092] The internal support is a steel structure, welded together from steel, including multiple layers of outer circumferential supports, multiple arc-shaped supports, multiple radial supports, multiple inner circumferential supports, and multiple vertical supports;

[0093] The outer circumferential support consists of three layers: an upper outer circumferential support 401, a middle outer circumferential support 402, and a lower outer circumferential support. There are 20 arc-shaped supports and 30 radial supports.

[0094] The inner ring support has 3 layers;

[0095] 40 vertical supports of different specifications.

[0096] The vertical support includes an outer vertical support, a middle vertical support, and an inner vertical support.

[0097] The upper outer circumferential support 401, the middle outer circumferential support 402 and the lower outer circumferential support are respectively welded to the inner sides of the upper reinforcing ring 301, the middle reinforcing ring 202 and the lower reinforcing ring 302, and the arc-shaped support is respectively welded to other spherical shell plates of the pressure-bearing boundary.

[0098] Specifically, the upper outer circumferential support 401 is radially welded with multiple radial supports 405, and the radial supports 405 are welded with an upper inner circumferential support 406. The upper outer circumferential support 401 is circumferentially welded with multiple arc-shaped supports 404, which are welded to one side of the middle outer circumferential support 402. The middle outer circumferential support 402 is radially welded with multiple radial supports 405, and the radial supports 405 are welded with an inner circumferential support 406 in the middle layer. The other side of the middle outer circumferential support 402 is circumferentially welded with multiple arc-shaped supports 404, which are welded to the lower outer circumferential support 402. 3. The lower outer circumferential support 403 is radially welded with multiple radial supports 405. The radial supports 405 are welded to an inner circumferential support 406 of the lower layer. The lower side of the upper outer circumferential support 401 is welded with multiple vertical supports 407. The vertical supports 407 are also welded to the radial supports 405 that connect the middle outer circumferential support 402 and an inner circumferential support 406 of the middle layer. The upper side of the lower outer circumferential support 403 is welded with multiple vertical supports 407. The vertical supports 407 are also welded to the radial supports 405 that connect the middle outer circumferential support 402 and an inner circumferential support 406 of the middle layer.

[0099] The outer circumferential support includes multiple outer circumferential support plates, which are connected by a large ring brace 408.

[0100] The inner ring support 406 includes inner ring support plates of multiple modules, and the inner ring support plates are connected by small ring supports 409.

[0101] Radial supports 405 are connected to vertical supports 407 via straight supports 410;

[0102] Multiple vertical supports 407 are connected to the outer circumferential support, the inner circumferential support 406, and the radial support 405 respectively through straight supports 410.

[0103] The external support includes a support 201, an upper tie rod 60 and a lower tie rod 70. One end of the upper tie rod 60 is connected to the upper reinforcing ring 301, and multiple upper tie rods 60 are evenly distributed on the upper reinforcing ring 301.

[0104] One end of the lower tie rod 70 is connected to the lower reinforcing ring 302, and multiple lower tie rods 70 are evenly distributed on the lower reinforcing ring 302;

[0105] Multiple supports 201 are evenly distributed on the central reinforcing ring 202, forming a central reinforcing ring support assembly 20.

[0106] The support 201 is connected to the internal support and transmits load through the middle reinforcing ring 202, the upper tie rod 60 is connected to the internal support and transmits load through the upper reinforcing ring 301, and the lower tie rod 40 is connected to the internal support and transmits load through the lower reinforcing ring 302.

[0107] The support 201 has multiple through anchor bolt holes on the top and bottom for anchor bolts to pass through.

[0108] The upper tie rod 60 and the lower tie rod 70 are arranged at a specific angle relative to the bearing boundary. This specific angle is determined by calculation based on the location of the connection point between the upper tie rod 60 and the lower tie rod 70, and the expansion displacement of the bearing boundary under thermal expansion conditions. The calculation process for this specific angle is as follows:

[0109] θ = arccos(0.5 × d / L)

[0110] Where θ is the angle between the normal direction of the water tank shell and the tie rod at the connection point between the water tank shell and the tie rod, d is the thermal expansion displacement of the water tank shell at the connection point, and L is the length of the tie rod.

[0111] Both ends of the upper tie rod 60 and the lower tie rod 70 are hinged and at a certain angle to the pressure-bearing boundary, which helps to improve the overall rigidity of the water tank equipment and enhance its seismic resistance. Under thermal expansion conditions, the pressure-bearing boundary expands radially outward, and both the upper tie rod 60 and the lower tie rod 70 can rotate around the hinge axis. Through a specific arrangement angle design, it can be ensured that the additional load caused by the thermal expansion of the water tank on the upper tie rod 60 and the lower tie rod 70 is minimized.

[0112] The present invention discloses a method for manufacturing a passive, high-level, ultra-large pressurized water tank for nuclear power plants based on the concept of rigid-flexible coordination, comprising the following steps:

[0113] Step 1: Weld the support and the central reinforcing ring together to prefabricate the central reinforcing ring support assembly, and transport all modular components to the assembly construction site;

[0114] Please refer to Figures 1-2As shown, specifically in step 1, the main body of the passive shell external pressure tank can be divided into five major components: the spherical shell plate 10 that bears the internal pressure, the middle reinforcing ring support assembly 20, the upper and lower reinforcing ring assemblies 30, the internal support assembly 40 that provides internal support, and the auxiliary support assembly 50 that plays an auxiliary role in the construction process. The structural dimensions of each component are relatively large. In the actual construction process, each component needs to be docked and positioned according to the specific quantity determined by the design, and then welded to form the main body of the passive shell external pressure tank.

[0115] For example, according to one embodiment of the present invention, please refer to Figure 1 As shown, the shell assembly 10, the middle reinforcing ring support assembly 20, and the upper and lower reinforcing ring assemblies 30 form a complete sphere with a diameter of 18 meters. The sphere supports the water source for the passive system and withstands temperature and pressure loads under accident conditions. The shell assembly 10 consists of 20 upper temperate plates 101, 20 lower temperate plates 102, 1 upper pole middle plate 103, 1 lower pole middle plate 106, 2 upper pole side plates 104, 2 lower pole side plates 107, 4 upper pole edge plates 105, and 4 lower pole edge plates 108.

[0116] Reference Figure 1 As shown, the middle reinforcing ring support assembly 20 and the upper and lower reinforcing ring assemblies 30 are connected to the shell plate 10 and are thicker than the shell plate 10, serving as support and reinforcement. The specific structure and anchor bolts are determined by calculation and design based on comprehensive consideration of the load on the water tank, seismic load, and construction load, and are evenly distributed. The specific number of modules can be determined based on the actual project and comprehensive consideration. The middle reinforcing ring support assembly 20 consists of 20 supports 201 and a middle reinforcing ring 202, and the upper and lower reinforcing ring assemblies 30 consist of an upper reinforcing ring 301 and a lower reinforcing ring 302.

[0117] The central reinforcing ring 202 is assembled from 20 modular central reinforcing ring plates;

[0118] The upper reinforcing ring 301 is assembled from 20 modular upper reinforcing ring plates;

[0119] The lower reinforcing ring 302 is assembled from 20 modular lower reinforcing ring plates.

[0120] The inner support assembly 40 is composed of 12 steel sections, forming a frame structure that enhances the overall stability of the complete sphere formed by the shell assembly 10, the middle reinforcing ring support assembly 20, and the upper and lower reinforcing ring assemblies 30, thereby improving the equipment's seismic resistance.

[0121] Step 2: Hoist each auxiliary support component into the precast foundation surface and assemble them into a whole, connecting them to form a support frame;

[0122] like Figures 3-4 As shown, the auxiliary support assembly 50 includes: a support plate 501, a support column 502, a support tie rod 503, and a support base plate 504;

[0123] The upper end of the support column 502 is connected to the support plate 501, and the lower end is connected to the support base plate 504;

[0124] The support rod 503 connects the adjacent support columns 504 together to form a frame structure;

[0125] The support rod 503 has an adjustment function to ensure the stability of the support frame.

[0126] The auxiliary support assembly 50 consists of 20 support plates 501, 20 support columns 502, support rods 503, and 20 support base plates 504.

[0127] The horizontal deviation of the upper surface of the 20 upper support plates shall not exceed 3 mm;

[0128] The support plate 501 supports the support 201.

[0129] Step 3: Hoist the reinforcing ring support assembly 20 onto the auxiliary support assembly 50 to form the support structure of the passive shell external pressure tank;

[0130] Multiple modular intermediate reinforcing ring support assemblies 20 are hoisted onto the auxiliary support assembly 50 to support the support 201; each intermediate reinforcing ring 202 is fixedly welded to the auxiliary support assembly 50 after adjustment and positioning, and is positioned by temporary fixing clamps 505 to prevent deformation.

[0131] Step 4: Weld the temperate zone plate 101 and the lower temperate zone plate 102 to both sides of the middle reinforcing ring 202 respectively;

[0132] Reference Figure 5 , 10 As shown, it specifically includes:

[0133] Multiple upper tempering plates 101 and lower tempering plates 102 are tack welded to the middle reinforcing ring 202 and positioned using temporary fixing clamps 505.

[0134] Remove the temporary fixing clamp 505, and weld the multiple upper temperate zone plates 101 and lower temperate zone plates 102 to the middle reinforcing ring 202 in full dimensions. After welding, perform non-destructive testing according to the construction drawings.

[0135] Step 5: Assemble the upper reinforcing ring 301 and the lower reinforcing ring 302, and weld them to the upper tempering plate 101 and the lower tempering plate 102 respectively;

[0136] Reference Figure 5 As shown, it specifically includes:

[0137] Multiple modular upper reinforcing ring plates are assembled into an upper reinforcing ring 301. The upper reinforcing ring 301 is tack welded to the upper tempering plate 101 and positioned by a temporary fixing clamp 505.

[0138] Multiple modular lower reinforcing plates are assembled into a lower reinforcing ring 302. The lower reinforcing ring 302 is tack welded to the lower temperate plate 102 and positioned by a temporary fixing clamp 505.

[0139] Remove the fixing clip 505, and weld the upper reinforcing ring 301 to the upper tempering plate 101 in full dimensions. After welding, perform non-destructive testing according to the construction drawings.

[0140] The lower reinforcing ring 302 is welded to the lower tempering plate 102 in full dimensions, and non-destructive testing is performed according to the construction drawings after welding.

[0141] Step 6: Position the internal support 40 and weld it together with the middle reinforcing ring 202, the upper warm zone plate 101, the lower warm zone plate 102, the upper reinforcing ring 301, and the lower reinforcing ring 302;

[0142] Specifically, it includes:

[0143] Reference Figures 6-8 As shown, the upper outer circumferential support 401, the middle outer circumferential support 402, and the lower outer circumferential support 403 are respectively assembled and welded to the upper reinforcing ring 301, the middle reinforcing ring 202, and the lower reinforcing ring 302.

[0144] Multiple radial supports 405 are radially welded to the upper outer circumferential support 401, and an upper inner circumferential support 406 is welded to the other end of the radial support 405.

[0145] Multiple radial supports 405 are radially welded to the outer circumferential support 402 in the middle part, and an inner circumferential support 406 of the middle layer is welded to the other end of the radial support 405.

[0146] Multiple radial supports 405 are radially welded to the lower outer circumferential support 403, and an inner circumferential support 406 of the lower layer is welded to the other end of the radial support 405.

[0147] The lower side of the upper outer circumferential support 401 is welded to multiple vertical supports 407. The vertical supports 407 are also welded to the radial support 405 that connects the middle outer circumferential support 402 and an inner circumferential support 406 in the middle layer. The upper side of the lower outer circumferential support 403 is welded to multiple vertical supports 407. The vertical supports 407 are also welded to the radial support 405 that connects the middle outer circumferential support 402 and an inner circumferential support 406 in the middle layer.

[0148] When the upper outer circumferential support 401, the middle outer circumferential support 402, the lower outer circumferential support 403, and the arc-shaped support 404 are welded to the upper reinforcing ring 301, the middle reinforcing ring 202, and the lower reinforcing ring 302, symmetrical intermittent welding is adopted to reduce the amount of welding and welding deformation.

[0149] Step 7: Assemble and weld the upper electrode plate to the upper reinforcing ring 301, and assemble and weld the lower electrode plate to the lower reinforcing ring 302;

[0150] Specifically, it includes:

[0151] like Figure 9 As shown, the upper electrode side plate 105, the lower electrode side plate 108 are assembled with the upper reinforcing ring 301 and the lower reinforcing ring 302 respectively. The upper electrode side plate 104, the lower electrode side plate 107, the upper electrode middle plate 103, and the lower electrode middle plate 106 are assembled in sequence. After assembly, welding is performed. After welding, non-destructive testing is performed according to the drawing requirements.

[0152] Step 8: Weld the upper tie rod 60 and the lower tie rod 70 to the upper reinforcing ring 301 and the lower reinforcing ring 302 respectively;

[0153] Specifically, it includes:

[0154] One side of the upper tie rod 60 and the lower tie rod 70 are welded to the upper reinforcing ring 301 and the lower reinforcing ring 302 respectively, and the other side is connected to the factory structure according to the actual structural dimensions of the installation.

[0155] Step 9: Weld the connecting pipe assembly 80 in the upper and lower electrode plates.

[0156] As can be seen from the above detailed description of the embodiments of the present invention, compared with the prior art, the construction method of the passive outer pressure tank of the nuclear power plant of the present invention changes the existing construction method of building scaffolding on the construction site and then carrying out construction inside the plant to component structure construction. Different components are hoisted into place, spliced, fixed, welded, inspected and hoisted by crane in a certain order to realize the overall introduction of the passive outer pressure tank.

[0157] In summary, the construction method for the passive outer pressure tank of a nuclear power plant according to the present invention has the following advantages:

[0158] 1) Passive shell external pressure water tank, each component is prefabricated in advance at the manufacturing plant, the construction conditions are good, the construction tools are complete, the processing accuracy is high, and the individual components can be processed well according to the construction drawings.

[0159] 2) For passive shell external pressure water tanks, all components are arranged in advance and prefabricated at the manufacturing plant according to the construction schedule, which greatly saves on-site construction time and effectively improves the construction progress.

[0160] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0161] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A passive high-level large pressurized water tank for nuclear power plant based on the concept of rigid-flexible coordination, characterized in that, include: Pressure boundary and equipment support; The pressure-bearing boundary is spherical and is made of spherical shell plates welded together, including a middle reinforcing ring, an upper reinforcing ring, a lower reinforcing ring, and other conventional spherical shell plates; The equipment support includes external support and internal support. The external support and internal support are connected and transfer load through the middle reinforcing ring, upper reinforcing ring and lower reinforcing ring in the pressure boundary. The internal support is a steel structure, welded together from steel, including multiple layers of outer circumferential supports, multiple arc-shaped supports, multiple radial supports, multiple inner circumferential supports, and multiple vertical supports; The external support includes a support, an upper tie rod, and a lower tie rod. One end of the upper tie rod is connected to the upper reinforcing ring, and multiple upper tie rods are evenly distributed on the upper reinforcing ring. One end of the lower tie rod is connected to the lower reinforcing ring, and multiple lower tie rods are evenly distributed on the lower reinforcing ring; The multiple supports are evenly distributed on the central reinforcing ring.

2. The passive high-level large pressurized water tank for nuclear power plant based on the rigid-flexible coordination concept according to claim 1, characterized in that, The outer circumferential support consists of three layers, including an upper outer circumferential support, a middle outer circumferential support, and a lower outer circumferential support. There are 20 arc-shaped supports, 30 radial supports, 3 layers of inner ring supports, and 40 vertical supports.

3. The passive high-level large pressurized water tank for nuclear power plant based on the rigid-flexible coordination concept according to claim 2, characterized in that, The upper outer circumferential support, the middle outer circumferential support, and the lower outer circumferential support are welded to the inner sides of the upper reinforcing ring, the middle reinforcing ring, and the lower reinforcing ring, respectively, and the arc-shaped support is welded to the other spherical shell plates of the pressure-bearing boundary.

4. The passive high-level large pressurized water tank for nuclear power plant based on the rigid-flexible coordination concept according to claim 1, characterized in that, The support is connected to the internal support and transmits load through the middle reinforcing ring, the upper tie rod is connected to the internal support and transmits load through the upper reinforcing ring, and the lower tie rod is connected to the internal support and transmits load through the lower reinforcing ring.

5. The passive high-level large pressurized water tank for nuclear power plant based on the rigid-flexible coordination concept according to claim 1, characterized in that, The support has multiple through anchor bolt holes on the top and bottom for anchor bolts to pass through.

6. The passive high-level large pressurized water tank for nuclear power plant based on the rigid-flexible coordination concept according to claim 1, characterized in that, The spherical shell plate includes an upper temperate plate, a lower temperate plate, an upper electrode plate, and a lower electrode plate; The upper electrode plate includes: upper middle plate, upper side plate, and upper edge plate, which are welded together to form the arc-shaped top of the water tank; The lower electrode plate includes: the lower electrode middle plate, the lower electrode side plate, and the lower electrode edge plate. The three are welded together to form the arc-shaped bottom of the water tank. Several upper temperate zone plates are arranged in an arc shape and positioned between the upper reinforcing ring and the middle reinforcing ring; Several lower temperate zone plates are arranged in an arc shape and positioned between the lower reinforcing ring and the middle reinforcing ring.

7. A method for manufacturing a passive high-level large pressurized water tank for a nuclear power plant based on the concept of rigid-flexible coordination, characterized in that, Includes the following steps: Step 1: Weld the support and the central reinforcing ring together to prefabricate the central reinforcing ring support assembly, and transport all modular components to the assembly construction site; Step 2: Hoist each auxiliary support component into the precast foundation surface and assemble them into a whole, connecting them to form a support frame; Step 3: Hoist the reinforcing ring support assembly onto the auxiliary support assembly to form the support structure of the passive shell external pressure tank; Step 4: Weld the temperate zone plate and the lower temperate zone plate to both sides of the middle reinforcing ring respectively; Step 5: Assemble the upper and lower reinforcing rings and weld them to the upper and lower tempering plates respectively; Step 6: Position the internal support and weld it to the middle reinforcing ring, upper warm zone plate, lower warm zone plate, and upper and lower reinforcing rings; Step 7: Assemble and weld the upper electrode plate to the upper reinforcing ring, and assemble and weld the lower electrode plate to the lower reinforcing ring; Step 8: Weld the upper tie rod and the lower tie rod to the upper reinforcing ring and the lower reinforcing ring respectively; Step 9: Weld the connecting pipe assemblies in the upper and lower electrode plates.

8. The method for manufacturing a passive high-level large pressurized water tank based on the rigid-flexible coordination concept for a nuclear power plant according to claim 7, characterized in that, The central reinforcing ring is assembled from multiple modular central reinforcing ring plates; The upper reinforcing ring is assembled from multiple modular upper reinforcing ring plates; The lower reinforcing ring is assembled from multiple modular lower reinforcing ring plates.

9. The manufacturing method of a passive high-level ultra-large pressurized water tank for nuclear power plants based on the rigid-flexible coordination concept according to claim 7, characterized in that, The auxiliary support assembly includes: a support plate, a support column, a support tie rod, and a support base plate; The upper end of the support column is connected to the support plate, and the lower end is connected to the support base plate; The tie rods connect adjacent support columns to form a frame structure; The support rod has an adjustment function.

10. The method for manufacturing a passive high-level large pressurized water tank for a nuclear power plant based on the rigid-flexible coordination concept according to claim 8, characterized in that, The auxiliary support assembly includes 20 support columns, 20 support plates and 20 support base plates, as well as support rods connecting the support columns; The horizontal deviation of the upper surface of the 20 upper support plates shall not exceed 3 mm; The support plate supports the bracket.

11. The method for manufacturing a passive high-level large pressurized water tank for a nuclear power plant based on the rigid-flexible coordination concept according to claim 7, characterized in that, In step 3, multiple modular intermediate reinforcing ring support assemblies are hoisted onto the auxiliary support assembly to provide support for the support; after each intermediate reinforcing ring and auxiliary support assembly are adjusted and positioned, they are fixedly welded and positioned using temporary fixing clamps to prevent deformation.

12. The manufacturing method of a passive high-level ultra-large pressurized water tank for nuclear power plants based on the rigid-flexible coordination concept according to claim 7, characterized in that, Step 4 specifically includes: Multiple upper and lower tempering plates are tack welded to the middle reinforcing ring and positioned using temporary fixing clamps; Remove the temporary fixing clamps, and weld the multiple upper and lower temperate zone plates to the central reinforcing ring in full dimensions. After welding, perform non-destructive testing according to the construction drawings.

13. The method for manufacturing a passive high-level large pressurized water tank for a nuclear power plant based on the rigid-flexible coordination concept according to claim 7, characterized in that, Step 5 specifically includes: Multiple modular upper reinforcing ring plates are assembled into an upper reinforcing ring, which is then positioned and welded to the upper tempering plate using a temporary fixing clamp. Multiple modular lower reinforcing plates are assembled into a lower reinforcing ring, which is then tack welded to the lower temperate zone plate and positioned using a temporary fixing clamp. Remove the fixing clamps, weld the upper reinforcing ring to the upper tempering plate to full dimensions, and perform non-destructive testing according to the construction drawings after welding; The lower reinforcing ring is welded to the lower tempered zone plate in full dimensions, and non-destructive testing is performed according to the construction drawings after welding.

14. The method for manufacturing a passive high-level large pressurized water tank for a nuclear power plant based on the rigid-flexible coordination concept according to claim 7, characterized in that, Step 6 specifically includes: The upper outer circumferential support, the middle outer circumferential support, and the lower outer circumferential support are respectively assembled and welded to the upper reinforcing ring, the middle reinforcing ring, and the lower reinforcing ring. Multiple radial supports are radially welded to the outer circumferential support of the upper part, and an inner circumferential support of the upper layer is welded to the other end of the radial supports. Multiple radial supports are radially welded to the outer circumferential support in the middle section, and an inner circumferential support of the middle layer is welded to the other end of the radial supports. Multiple radial supports are radially welded to the lower outer circumferential support, and an inner circumferential support of the lower layer is welded to the other end of the radial support. The lower side of the upper outer circumferential support is welded to multiple vertical supports, which are simultaneously welded to a radial support connecting the middle outer circumferential support and an inner circumferential support of the middle layer. The upper side of the lower outer circumferential support is welded to multiple vertical supports, which are simultaneously welded to a radial support connecting the middle outer circumferential support and an inner circumferential support of the middle layer.

15. The method for manufacturing a passive high-level large pressurized water tank for a nuclear power plant based on the rigid-flexible coordination concept according to claim 7, characterized in that, Step 7 specifically includes: The upper and lower electrode side plates are assembled with the upper and lower reinforcing rings respectively. The upper electrode side plate, lower electrode side plate, upper electrode middle plate, and lower electrode middle plate are assembled in sequence and then welded. After welding, non-destructive testing is performed according to the drawing requirements.

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