Turbulence form control device and reactor

Abstract

The invention discloses a turbulent flow form control device and a reactor. The turbulent flow form control device comprises an upper-layer drainage structure and a lower-layer rectification structure which are sequentially arranged from top to bottom, a plurality of drain holes are formed in the upper-layer drainage structure and the lower-layer rectification structure; the upper drainage structure is used for draining fluid entering the lower chamber from the annular descending channel in the reactor; and the lower-layer rectification structure is used for performing form control on fluid entering the middle cavity of the lower cavity. According to the turbulent flow form control device, the turbulent flow form of the reactor pressure vessel can be controlled, so that the flow entering a reactor core inlet is uniform and stable, large flow pulsation is avoided, the fluid energy is relatively low, and the frequency is relatively high; and the influence of turbulent flow of the area in front of the reactor core inlet on oscillation of the fuel assembly and nuclear power fluctuation of the reactor core can be improved or eliminated, and stable power output of the reactor core is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of reactor pressure vessels, and particularly to a turbulent flow pattern control device and a reactor. Background Art

[0002] The reactor body of a pressurized water reactor consists of a reactor pressure vessel (RPV, the full name is Reactor Pressure Vessel), reactor vessel internals (RVI, the full name is Reactor Vessel Internals), control rod drive mechanisms, core components, core instrumentation, and related components. The reactor vessel internals, together with the pressure vessel and the fuel assembly structure itself, provide a reasonable flow path for the core. The coolant flows in from the inlet nozzle of the reactor pressure vessel, enters the annular downcomer, changes the flow direction to vertically upward in the lower plenum, flows through the flow distribution device and the lower core support plate (LSP, the full name is Lower core Support Plate), and enters the core to achieve core cooling. The flow path of the coolant fluid in the reactor is as Figure 1 shown.

[0003] Due to the non-uniformity of the entire flow path structure, a large number of bluff body turbulences, and a relatively high flow velocity, a high-speed non-uniform flow, i.e., a turbulent flow phenomenon, always exists in the reactor. According to the gradual change theory of the turbulent flow scale evolution of Kolmogorov and Richardson (i.e., the energy cascade theory of turbulence): large-scale vortices obtain energy from the time-averaged flow through turbulent shear, and then, in the process of viscous dissipation, these large-scale vortices are continuously split into different small-scale vortices, and the energy is gradually transferred to smaller-scale vortices during the splitting and fragmentation process of the vortex body until viscous dissipation is reached. That is, the energy of the turbulent flow has a direct relationship with the vortex scale. The larger the scale, the higher the energy and the lower the frequency.

[0004] The reactor core usually consists of 100 to 300 fuel assemblies. If there is no reasonable turbulent flow pattern control structure before the core inlet in the lower plenum, large and unstable turbulent vortices may be generated in the lower plenum, which will cause uneven flow distribution of the fluid entering the core (i.e., a large flow difference between each fuel assembly) and large fluid pulsations (i.e., a large flow fluctuation of the fluid entering the same group of fuel assemblies within a certain period of time). In addition, energy spectrum analysis of the flow rate when there are large vortices in the lower plenum shows that its power spectral density presents a situation of higher energy, lower frequency, and even close to the natural frequency of the fuel assembly (the first-order natural frequency of the fuel assembly is about between 1 Hz and 3 Hz). The above phenomena will cause obvious lateral flow changes of the fuel assemblies, cause changes in the gaps between the fuel assemblies, and ultimately lead to low-frequency oscillations of the fuel assemblies, further causing an increase in the amplitude of the core power fluctuation and aggravating the wear of the fuel assembly grids, ultimately affecting the safe and economic operation of the reactor.

[0005] In the structure of traditional pressurized water reactor internal components (or pressure vessels), a flow distribution device or a structural device with similar functions is usually set under the core. After the coolant flows through the flow distribution device and the porous lower core support plate, the flow distribution function is realized to ensure an acceptable uniformly distributed flow at the core inlet. However, this device pays more attention to the uniformity in "space" and does not pay attention to the uniformity of the aforementioned turbulence in time, and the influence of energy and frequency brought by the turbulence scale.

[0006] Patent CN118448074A proposes a method for constructing and controlling the turbulent flow morphology of fluid inside a reactor pressure vessel, and proposes that the three-dimensional structure inside the reactor pressure vessel can be modified to further improve the three-dimensional flow field inside the reactor, control the turbulent flow morphology, and ultimately make the flow at the core inlet uniform and stable, without large flow pulsation and hydraulic excitation, so that the core can output power steadily. Based on this, it is necessary to design a device structure that can control the turbulent flow morphology of fluid inside the reactor.

[0007] In one of the prior art technologies, there is no dedicated flow distribution device at the bottom of the lower support plate of the reactor internals. Instead, the core instrument guide column, secondary support column, upper and lower grid plates, porous lower core support plate with holes and porous lower core plate with holes below the core support plate play a similar flow distribution function together, such as Figure 2 After the coolant enters the lower chamber from the annular descending channel, it is mixed through the instrument guide column, the secondary support column and the upper and lower grid plates, and then passes through the lower core support plate and the lower core plate. However, the above technical solution has the following technical defects:

[0008] A1) The lower chamber has many "columnar structures", which generate a large number of fluid vortices and vortex shedding, resulting in unstable flow and making it difficult to effectively control the turbulent flow pattern in the lower chamber;

[0009] A2) Due to the different sizes of the "columnar structures", the size, frequency and energy of the vortices generated are different, so the fluid flow state in the lower chamber is relatively chaotic, the flow distribution uniformity at the core inlet is poor, and there is also obvious fluid pulsation at the inlet of each fuel assembly;

[0010] A3) The structure is complex. The flow distribution function requires the joint action of instrument guide columns, secondary support columns, upper and lower grid plates, lower core support plates and lower core plates. There are many parts. During operation, under the impact of high-speed coolant, parts are prone to loosening and falling, resulting in safety risks.

[0011] In other existing technologies, a dedicated flow distribution component is adopted at the bottom of the core support plate of the in-core components. The structure description is as follows Figure 3 As shown, the flow distribution component consists of an annular cylinder, a mesh orifice plate, and multiple tie rods. Each tie rod is connected to the core support plate through bolts. The schematic diagram of the installation in the reactor is as follows Figure 4 As shown, however, the following technical defects exist in the above technical solution:

[0012] B1) The flow distribution component fails to cover the entire core, and the overall flow distribution effect is poor. The flow difference between the middle and the edge is large, and the deviation of the maximum flow distribution unevenness coefficient is about 20%.

[0013] B2) The flow distribution component fails to cover the entire core, and there is a cavity between the edge of the flow distribution device and the lower head. It is impossible to control the turbulent flow pattern, and large-scale vortices are easily formed, corresponding to higher energy and lower frequency, resulting in a more significant fluid pulsation phenomenon and easily forming a large hydraulic excitation on the fuel assembly at the core inlet.

[0014] B3) The mesh orifice plate in the flow distribution device has a large aperture and a small number, and the flow distribution effect is poor. It is difficult to control the turbulent flow pattern in the lower chamber, and the generated vortex sizes are large and uneven, easily leading to large flow pulsations.

[0015] B4) The structure is relatively complex, and the number of connecting bolts is large. The holes on the mesh orifice plate are square holes, and the orifice plate structure is processed from forgings, resulting in a high cost. Summary of the Invention

[0016] The embodiments of the present invention provide a turbulent flow pattern control device and a reactor, aiming to solve the problem that in the prior art, a flow distribution device or a structure device with a similar function is provided in front of the core inlet of the lower chamber of the reactor pressure vessel of the pressurized water reactor reactor body, but a reasonable turbulent flow pattern control structure is not provided. Although the flow distribution function can be realized to ensure an acceptable uniformly distributed flow at the core inlet, more attention is paid to the uniformity in "space", and the uniformity of the aforementioned turbulence in time and the influence of the energy and frequency brought by the turbulent scale are not concerned.

[0017] In a first aspect, the embodiments of the present invention provide a turbulent flow pattern control device applied to a reactor, which includes an upper layer diversion structure and a lower layer rectification structure arranged in sequence from top to bottom; a plurality of water flow holes are provided in both the upper layer diversion structure and the lower layer rectification structure; the upper layer diversion structure is used to divert the fluid entering the lower chamber from the annular downcomer in the reactor; the lower layer rectification structure is used to control the fluid pattern of the fluid entering the middle cavity of the lower chamber.

[0018] In some embodiments, the turbulent flow pattern control device further includes a middle flow equalizing structure, which is arranged at the intersection position between the upper layer diversion structure and the lower layer rectifying structure, and a plurality of water flow holes are provided in the middle flow equalizing structure; the middle flow equalizing structure is used to rectify the fluid entering from the lower layer rectifying structure before it enters the reactor core of the reactor.

[0019] In some embodiments, the ratio between the channel width between the upper layer diversion structure and the wall surface of the lower chamber of the reactor pressure vessel and the width of the annular downcomer of the reactor is 0.5 to 3.

[0020] In some embodiments, the height of the upper layer diversion structure is 10% to 80% of the distance between the lower support plate of the reactor core and the bottom of the lower chamber of the pressure vessel.

[0021] In some embodiments, the upper layer diversion structure is a partial hemispherical, semi-elliptical, conical or butterfly shape, and the wall thickness of the upper layer diversion structure is 10 mm to 150 mm.

[0022] In some embodiments, there are 2 - 8 layers of water flow holes arranged from top to bottom in the upper layer diversion structure.

[0023] In some embodiments, each layer of the 2 - 8 layers of water flow holes in the upper layer diversion structure includes a plurality of first water flow holes, and the equivalent diameter corresponding to the plurality of first water flow holes in each layer of water flow holes is 20 mm to 150 mm.

[0024] In some embodiments, the lower layer rectifying structure is a cylindrical thin-walled structure, and the top of the lower layer rectifying structure is connected to the bottom of the upper layer diversion structure.

[0025] In some embodiments, the height of the lower layer rectifying structure is 10% to 80% of the distance between the lower support plate of the reactor core and the bottom of the lower chamber of the pressure vessel.

[0026] In some embodiments, the sum of the height of the lower layer rectifying structure and the height of the upper layer diversion structure is less than the distance between the lower support plate of the reactor core and the bottom of the lower chamber of the pressure vessel.

[0027] In some embodiments, the distance between the bottom of the lower layer rectifying structure and the wall surface of the lower chamber of the pressure vessel is greater than 0.

[0028] In some embodiments, the wall thickness of the lower layer rectifying structure is 10 mm to 150 mm.

[0029] In some embodiments, there are 2 - 8 layers of water flow holes arranged from top to bottom in the lower layer rectifying structure.

[0030] In some embodiments, each layer of the 2-8 layers of water flow holes in the lower rectifying structure includes a plurality of second water flow holes, and the equivalent diameter corresponding to the plurality of second water flow holes in each layer of water flow holes is 20 mm to 150 mm.

[0031] In some embodiments, the middle flow equalizing structure is a flat plate or an arc plate provided with multiple layers of water flow holes, and the structural thickness of the middle flow equalizing structure is 10 mm to 300 mm.

[0032] In some embodiments, there are 2-15 circles of water flow holes arranged from the inside to the outside in the middle flow equalizing structure.

[0033] In some embodiments, each circle of the 2-15 circles of water flow holes in the middle flow equalizing structure includes a plurality of third water flow holes, and the equivalent diameter corresponding to the plurality of third water flow holes in each circle of water flow holes is 20 mm to 150 mm.

[0034] In some embodiments, the number of water flow holes corresponding to the plurality of third water flow holes in each circle of water flow holes in the middle flow equalizing structure is 1 to 100.

[0035] In a second aspect, an embodiment of the present application further provides a reactor, which includes the turbulent flow pattern control device described in the first aspect and any possible embodiment thereof as above.

[0036] In some embodiments, the reactor further includes a reactor pressure vessel cylinder, an annular downcomer, a core lower support plate, a reactor core, and a radial support key; wherein, the annular downcomer is arranged inside the reactor pressure vessel cylinder; the radial support key is arranged on the inner wall of the reactor pressure vessel cylinder; the core lower support plate is fixedly arranged inside the reactor pressure vessel cylinder through the radial support key; the top of the turbulent flow pattern control device is connected to the radial support key, or is fixedly connected to the bottom surface of the core lower support plate through a fixing member; the reactor core is arranged on the core lower support plate.

[0037] Embodiments of the present invention provide a turbulent flow pattern control device and a reactor. The turbulent flow pattern control device is applied to the reactor and includes an upper flow guiding structure and a lower flow rectifying structure arranged successively from top to bottom; a plurality of water flow holes are provided in both the upper flow guiding structure and the lower flow rectifying structure; the upper flow guiding structure is used to guide the fluid that enters the lower chamber from the annular downcomer in the reactor; the lower flow rectifying structure is used to control the fluid pattern of the fluid entering the middle cavity of the lower chamber. The above-mentioned turbulent flow pattern control device can not only control the turbulent flow pattern of the reactor pressure vessel, make the flow rate at the inlet of the reactor core uniform and stable, without large flow rate pulsations, and the fluid energy is low and the frequency is high; but also can improve or eliminate the influence of the turbulence in the area before the inlet of the reactor core on the oscillation of the fuel assembly and the fluctuation of the core nuclear power, ensure the stable output of power by the core, and enable the nuclear power plant to operate safely and stably. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0039] Figure 1 It is a schematic diagram of the coolant flow field in an existing reactor pressure vessel;

[0040] Figure 2 It is a schematic diagram of the structure of the lower chamber of an existing reactor pressure vessel;

[0041] Figure 3 It is a schematic diagram of the structure of the flow rate distribution assembly in an existing reactor pressure vessel;

[0042] Figure 4 It is a schematic cross-sectional structure diagram of the flow rate distribution assembly in an existing reactor pressure vessel;

[0043] Figure 5 It is a schematic diagram of the structure of the turbulent flow pattern control device provided by the embodiment of the present invention;

[0044] Figure 6 It is another schematic diagram of the structure of the turbulent flow pattern control device provided by the embodiment of the present invention;

[0045] Figure 7 It is a schematic cross-sectional structure diagram of the reactor provided by the embodiment of the present invention;

[0046] Figure 8 For the present invention Figure 6 It is another perspective structure diagram of the turbulent flow pattern control device shown in the present invention;

[0047] Figure 9For the present invention Figure 6 Schematic top - view structural diagram of the turbulent flow pattern control device shown;

[0048] Figure 10 For the present invention Figure 6 Schematic side - view structural diagram of the turbulent flow pattern control device shown. Detailed implementation manners

[0049] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0050] It should be understood that when used in this specification and the appended claims, the terms "comprises" and "comprising" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0051] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0052] It should be further understood that the term "and / or" used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0053] Please refer to Figure 5 and Figure 7 , where Figure 5 is the schematic structural diagram of the turbulent flow pattern control device provided by the embodiment of the present invention; Figure 7 is the schematic sectional structural diagram of the reactor provided by the embodiment of the present invention. As shown in Figure 5 and Figure 7 shown, the turbulent flow pattern control device 1 disclosed in the embodiments of the present application is applied to a reactor. The turbulent flow pattern control device includes an upper flow - guiding structure 10 and a lower flow - straightening structure 20 arranged in sequence from top to bottom; a plurality of water - flowing holes are provided in both the upper flow - guiding structure 10 and the lower flow - straightening structure 20; the upper flow - guiding structure 10 is used to guide the fluid that enters the lower chamber from the annular down - flow channel 3 in the reactor; the lower flow - straightening structure 20 is used to control the fluid pattern of the fluid entering the middle cavity of the lower chamber.

[0054] In this embodiment, as the first embodiment of the turbulence morphology control device 1, the connection between the upper drainage structure 10 and the lower rectifying structure 20 is welding or integral molding. The turbulence morphology control device can be more specifically applied to the reactor pressure vessel of a pressurized water reactor, and can control the turbulence morphology of the reactor pressure vessel (such as the flow velocity of the fluid, the number, scale and frequency of vortices, etc.), so that the flow entering the reactor core inlet is uniform and stable, without large flow pulsation, and the fluid energy is low and the frequency is high. Moreover, it can also improve or eliminate the influence of the turbulence in the front area of ​​the reactor core inlet on the fuel assembly oscillation (FAO, its full name is Fuel Assembly Oscillation) and the core nuclear power fluctuation (NFF, its full name is Neutron Flux Fluctuations), ensure the core to output power steadily, and make the nuclear power plant operate safely and stably.

[0055] In order to more clearly understand the technical solution of the present application, the specific location of the turbulence morphology control device is described below in conjunction with the structure of a complete reactor. Figure 7 As shown, the reactor (specifically a pressurized water reactor) includes a reactor pressure vessel cylinder 2, an annular descending channel 3, a core lower support plate 4, a reactor core 5, a radial support key 6 and a turbulence morphology control device 1 (it should be noted that Figure 7 Not all structures in the reactor are shown, only some structures are shown); wherein the annular descending channel 3 is arranged in the reactor pressure vessel cylinder 2; the radial support key 6 is arranged on the inner wall of the reactor pressure vessel cylinder 2; the core lower support plate 4 is fixed in the reactor pressure vessel cylinder 2 through the radial support key 6; the top of the turbulence morphology control device 1 is connected (such as through a lug structure) to the radial support key 6, or is fixedly connected to the bottom surface (i.e., the lower surface) of the core lower support plate 4 through a fixing member (such as a locating pin or bolt); the reactor core 5 is arranged on the core lower support plate 4. wherein the area in the inner cavity of the reactor pressure vessel cylinder 2 below the core lower support plate 4 is regarded as the pressure vessel lower chamber 21; the annular descending channel 3 can be regarded as being arranged around the outer wall of the reactor core 5 (i.e., the area between the inner wall of the reactor pressure vessel cylinder 2 and the reactor core 5).

[0056] First, when the fluid (such as coolant) in the reactor enters the lower chamber (that is, the lower chamber of the pressure vessel) from the reactor through the annular descending channel 3, if it is drained through the upper drainage structure 10, the size of the fluid flow channel in the lower chamber of the reactor (that is, the lower chamber of the pressure vessel) can be controlled, so that when the fluid just leaves the annular descending channel 3 and enters the lower chamber, there will be no separation flow (the phenomenon that the fluid no longer flows along the solid surface due to the sudden enlargement or discontinuous change of the flow channel, but separates from the solid surface), thereby avoiding the occurrence of obvious large-scale vortices or vortex shedding. Afterwards, when the fluid enters the middle cavity of the lower chamber from the lower chamber, due to the existence of the lower-layer rectifying structure 20, the turbulent form of the fluid entering the middle cavity of the lower chamber can be controlled, and the form of the fluid is controlled through multiple small flow channels to be a stable stratified flow or only produce a smaller scale (equivalent diameter less than 200mm) vortex, avoiding the generation of large turbulent vortices (which may produce higher hydraulic excitation and a frequency close to the natural frequency of the fuel assembly) during the process of the fluid changing direction in the lower chamber.

[0057] Please also see Figure 6 and Figure 7 ,in Figure 6 Another schematic diagram of the structure of the turbulence morphology control device provided by an embodiment of the present invention; Figure 7 The cross-sectional structure diagram of the reactor provided by the embodiment of the present invention is shown in FIG. Figure 6 and Figure 7 As shown, the turbulence morphology control device 1 disclosed in the embodiment of the present application is applied to a reactor, and the turbulence morphology control device 1 includes an upper drainage structure 10 and a lower rectifying structure 20 arranged in sequence from top to bottom; the upper drainage structure 10 and the lower rectifying structure 20 are both provided with a plurality of water flow holes; the upper drainage structure 10 is used to drain the fluid entering the lower chamber from the annular descending channel 3 in the reactor; the lower rectifying structure 20 is used to control the fluid morphology of the fluid entering the middle cavity of the lower chamber; and also includes a middle flow balancing structure 30, the middle flow balancing structure 30 is arranged at the intersection of the upper drainage structure 10 and the lower rectifying structure 20, and the middle flow balancing structure 30 is provided with a plurality of water flow holes; the middle flow balancing structure 30 is used to rectify the fluid entering from the lower rectifying structure 20 before entering the reactor core 5 of the reactor. That is, the turbulence morphology control device 1 is provided with an upper flow guiding structure 10, a middle flow balancing structure 30 and a lower flow rectifying structure 20 in sequence from top to bottom.

[0058] In this embodiment, as the second embodiment of the turbulent flow pattern control device 1, the difference from the first embodiment is that a middle flow equalizing structure 30 is added at the junction position between the upper layer diversion structure 10 and the lower layer rectifying structure 20. That is, the bottom of the upper layer diversion structure 10 is connected to the top of the lower layer rectifying structure 20, and the middle flow equalizing structure 30 is located at the junction position between the upper layer diversion structure 10 and the lower layer rectifying structure 20. The connection manner among the upper layer diversion structure 10, the middle flow equalizing structure 30, and the lower layer rectifying structure 20 is welding or integral molding. The turbulent flow pattern control device can be more specifically applied to the reactor pressure vessel of a pressurized water reactor, and can control the turbulent flow pattern of the reactor pressure vessel (such as the flow velocity of the fluid, the number, scale, and frequency of the vortices, etc.), so that the flow rate entering the reactor core inlet is uniform and stable, without large flow pulsations, and the fluid energy is low and the frequency is high. Moreover, it can also improve or eliminate the influence of the turbulence in the area before the reactor core inlet on the fuel assembly oscillation (FAO, the full name is Fuel Assembly Oscillation) and the core nuclear power fluctuation (NFF, the full name is Neutron Flux Fluctuations), ensure the stable output of power from the core, and enable the nuclear power plant to operate safely and stably.

[0059] Among them, in order to more clearly understand the technical solution of another embodiment of the present application, the specific installation position of the turbulent flow pattern control device will be described below in conjunction with the structure of a complete reactor (such as Figure 7 shown).

[0060] First, when the fluid (such as coolant) in the reactor enters the lower chamber (i.e., the lower chamber of the pressure vessel) from the reactor through the annular downcomer 3, if it is drained through the upper drainage structure 10, the flow channel size of the fluid in the lower chamber of the reactor (i.e., the lower chamber of the pressure vessel) can be controlled, so that the fluid will not exhibit separated flow (the phenomenon that the fluid no longer adheres to the solid surface and separates from the solid surface due to a sudden increase or discontinuous change in the flow channel) when it just leaves the annular downcomer 3 and enters the lower chamber, thus avoiding the occurrence of obvious large-scale vortices or vortex shedding. After that, when the fluid enters the middle cavity of the lower chamber from the lower chamber, due to the existence of the lower rectifying structure 20, the turbulent flow pattern of the fluid entering the middle cavity of the lower chamber can be controlled, and the fluid pattern is controlled to be a stable stratified flow or only generate vortices with a smaller scale (equivalent diameter less than 200 mm) through multiple small flow channels, avoiding the generation of large turbulent vortices (which may generate high hydraulic excitation and frequencies close to the natural frequency of the fuel assembly) during the process of the fluid changing direction in the lower chamber. Finally, when the fluid flows back from the middle cavity of the lower chamber into the reactor core 5, the laterally flowing fluid has been changed into an upward flowing fluid. If it also passes through the secondary rectification of the middle flow equalizing structure 30, the flow rate of the fluid is evenly distributed to each fuel assembly of the reactor core.

[0061] In one embodiment, as Figures 6 - 10 shown, the ratio of the channel width between the upper drainage structure 10 and the wall surface of the lower chamber 21 of the pressure vessel of the reactor to the width of the annular downcomer 3 of the reactor is 0.5 to 3.

[0062] In this embodiment, in order to drain the fluid coming out of the annular downcomer 3 and entering the lower chamber, so that it flows in a flow channel with the same size as the original flow channel and slowly increases, and to avoid the separated flow caused by a sudden expansion or discontinuous change in the flow channel and thus form large turbulent vortices, the ratio of the channel width between the upper drainage structure 10 and the wall surface of the lower chamber 21 of the pressure vessel of the reactor to the width of the annular downcomer 3 of the reactor can be 0.5 to 3. Among them, the preferred ratio of the channel width between the upper drainage structure 10 and the wall surface of the lower chamber 21 of the pressure vessel of the reactor to the width of the annular downcomer 3 of the reactor is 1 to 1.5.

[0063] In one embodiment, as Figures 6 - 10 shown, the height of the upper drainage structure 10 is 10% to 80% of the distance between the lower support plate 4 of the reactor core and the bottom 22 of the lower chamber of the pressure vessel.

[0064] In this embodiment, when the height of the upper flow guiding structure 10 is 10% to 80% of the distance between the core lower support plate 4 of the reactor and the bottom 22 of the lower chamber of the pressure vessel, not only is the formation of separated flow due to sudden expansion or discontinuous change of the flow channel avoided, thus preventing the formation of large turbulent vortices, but also the overall structural strength of the turbulent flow pattern control device is ensured. Preferably, the height of the upper flow guiding structure 10 is 30% to 60% of the distance between the core lower support plate 4 of the reactor and the bottom 22 of the lower chamber of the pressure vessel.

[0065] In one embodiment, as Figures 6 - 10 shown, the upper flow guiding structure 10 is partially hemispherical, semi-ellipsoidal, conical or butterfly-shaped, and the wall thickness of the upper flow guiding structure is 10 mm to 150 mm.

[0066] In this embodiment, when the upper flow guiding structure 10 with the above structure is adopted, it can be ensured that it is a reduced-diameter structure with the largest inner diameter at the top and the smallest radius at the bottom, so that the channel between the upper flow guiding structure 10 and the wall surface of the lower chamber 21 of the pressure vessel of the reactor changes slowly and continuously compared with the width of the annular downcomer 3, avoiding the formation of separated flow due to sudden expansion or discontinuous change of the flow channel, thus preventing the formation of large turbulent vortices. Moreover, in order to improve the flow guiding effect of the upper flow guiding structure 10 on the fluid, its wall thickness should neither be too thin nor too thick, and it can be set to 10 mm to 150 mm.

[0067] In one embodiment, as Figures 6 - 10 shown, the upper flow guiding structure 10 is provided with 2 - 8 layers of water flow holes from top to bottom.

[0068] In this embodiment, some of the fluid flowing out of the annular downcomer 3 and entering the lower chamber can also guide part of the fluid into the edge position of the core inlet region of the reactor core 5 through the water flow holes of the upper flow guiding structure 10, avoiding the phenomenon of low flow rate at the edge position of the subsequent reactor core 5. In order to improve the flow guiding effect of the upper flow guiding structure 10 on the fluid, 2 - 8 layers of water flow holes can also be correspondingly set according to the actual situation. More specifically, the number of layers of water flow holes provided in the upper flow guiding structure 10 is positively correlated with the height of the upper flow guiding structure 10, that is, the greater the height of the upper flow guiding structure 10, the more layers of water flow holes are set, and the smaller the height of the upper flow guiding structure 10, the fewer layers of water flow holes are set. It should be noted that in order to ensure the flow guiding efficiency, at least 2 layers of water flow holes should be provided from top to bottom in the upper flow guiding structure 10.

[0069] In one embodiment, as Figures 6 - 10 shown, each layer of the 2 - 8 layers of water flow holes in the upper flow guiding structure 10 includes a plurality of first water flow holes 101, and the equivalent diameter corresponding to the plurality of first water flow holes 101 in each layer of water flow holes is 20 mm to 150 mm.

[0070] In this embodiment, each layer of the flow holes in the 2-8 layers of the upper drainage structure 10 includes a plurality of first flow holes 101. Moreover, the shape of the first flow holes 101 can be circular, square (with rounded corners), rectangular (with rounded corners), oval, three-leaf plum blossom, four-leaf plum blossom, or five-leaf plum blossom hole type, etc. (preferably circular and rectangular). The drilling direction of the first flow holes 101 can be the horizontal direction or the direction perpendicular to the cylinder body direction of the upper drainage structure 10 (it can be understood that the direction line corresponding to the drilling direction of the first flow holes 101 is perpendicular to the wall surface of the position where the first flow holes 101 are arranged in the upper drainage structure 10).

[0071] Among them, the equivalent diameter of the plurality of first flow holes 101 in each layer is 20 mm to 150 mm, and the number of the first flow holes included in each layer is between 10 and 100. Moreover, the equivalent diameters of the plurality of first flow holes 101 in each layer can be different, and preferably, the apertures of the plurality of first flow holes 101 in the same layer are the same.

[0072] In one embodiment, as Figures 6 - 10 shown, the lower rectifying structure 20 is a cylindrical thin-wall structure, and the top of the lower rectifying structure 20 is connected to the bottom of the upper drainage structure 10.

[0073] In this embodiment, the lower rectifying structure 20 can control the turbulent flow pattern of the fluid entering the middle cavity of the lower chamber. On the one hand, it can limit the velocity of the fluid to avoid the fluid having too high a velocity when changing direction (from flowing downward to flowing horizontally) in the lower chamber, resulting in the mainstream concentrating at the middle position of the cavity of the lower chamber, leading to uneven flow rate distribution at the inlet position of the subsequent reactor core 5 (larger in the middle and smaller at the edges). On the other hand, it can control the turbulent flow pattern of the fluid to a stable stratified flow or only generate small-scale vortices through the flow channels formed by a plurality of small flow holes, avoiding the generation of large turbulent vortices.

[0074] Moreover, when the lower rectifying structure 20 of the cylindrical thin-wall structure is adopted, it can effectively divide the cavity of the lower chamber into an external cavity (corresponding to the area between the outer wall of the lower rectifying structure 20 and the wall surface of the lower chamber 21 of the pressure vessel) and an internal cavity (i.e., the middle of the cavity of the lower chamber). In this way, the fluid flows to the external cavity of the lower chamber after being drained by the upper drainage structure 10, and then the fluid flows to the middle position of the cavity of the lower chamber after being rectified by the lower rectifying structure 20. It can be seen that through the rectification of the fluid by the lower rectifying structure, the fluid does not directly concentrate at the middle position of the cavity of the lower chamber, but controls the turbulent flow pattern of the fluid to a stable stratified flow or only generates small-scale vortices through the flow channels formed by a plurality of flow holes on the lower rectifying structure, and then the fluid can flow more smoothly to the middle flow equalizing structure.

[0075] In one embodiment, as Figures 6 - 10 shown, the height of the lower rectifying structure 20 is 10% - 80% of the distance between the lower support plate 4 of the reactor core and the bottom 22 of the lower cavity of the pressure vessel. The sum of the height of the lower rectifying structure 20 and the height of the upper diversion structure 10 is less than the distance between the lower support plate 4 of the reactor core and the bottom 22 of the lower cavity of the pressure vessel, and the distance between the bottom of the lower rectifying structure and the wall surface of the lower cavity of the pressure vessel is greater than 0.

[0076] In this embodiment, when the height of the lower rectifying structure 20 is 10% - 80% of the distance between the lower support plate 4 of the reactor core and the bottom 22 of the lower cavity of the pressure vessel, not only the fluid rectifying effect is ensured, but also the overall structural strength of the turbulent flow form control device is ensured. Preferably, the height of the lower rectifying structure 20 is 30% - 60% of the distance between the lower support plate 4 of the reactor core and the bottom 22 of the lower cavity of the pressure vessel. Moreover, when the distance between the bottom of the lower rectifying structure and the wall surface of the lower cavity of the pressure vessel (i.e., Figure 6 there is a gap 23 between the bottom of the lower rectifying structure in the middle and the wall surface of the lower cavity of the pressure vessel) is greater than 0, it can avoid the interference between the lower rectifying structure and the bottom of the lower cavity due to the expansion of the lower rectifying structure caused by the increase of the reactor operating temperature.

[0077] In one embodiment, as Figures 6 - 10 shown, the wall thickness of the lower rectifying structure 20 is 10 mm - 150 mm.

[0078] In this embodiment, in order to improve the rectifying effect of the lower rectifying structure 20 on the fluid, its wall thickness should neither be too thin nor too thick, and it can be set to 10 mm - 150 mm.

[0079] In one embodiment, as Figures 6 - 10 shown, there are 2 - 8 layers of flow holes arranged from top to bottom in the lower rectifying structure 20.

[0080] In this embodiment, when the fluid flows from the external cavity of the lower cavity through the lower rectifying structure 20 and is rectified and then flows to the middle position of the lower cavity, in order to ensure the rectifying effect on the fluid, there are 2 - 8 layers of flow holes arranged from top to bottom along the height direction of the lower rectifying structure 20. More specifically, the number of layers of flow holes arranged in the lower rectifying structure 20 is positively correlated with the height of the lower rectifying structure 20, that is, the greater the height of the lower rectifying structure 20, the more layers of flow holes are arranged, and the smaller the height of the lower rectifying structure 20, the fewer layers of flow holes are arranged. It should be noted that in order to ensure the diversion efficiency, at least 2 layers of flow holes are arranged from top to bottom in the lower rectifying structure 20.

[0081] In one embodiment, as Figures 6 - 10As shown, each layer of the 2 - 8 layer of flow holes in the lower rectifying structure 20 includes a plurality of second flow holes 201, and the equivalent diameter corresponding to the plurality of second flow holes 201 in each layer of flow holes is 20 mm to 150 mm.

[0082] In this embodiment, each layer of the 2 - 8 layer of flow holes in the lower rectifying structure 20 includes a plurality of second flow holes 201. Moreover, the shape of the second flow holes 201 can be circular, square (with rounded corners), rectangular (with rounded corners), oval, three - leaf plum blossom, four - leaf plum blossom or five - leaf plum blossom hole type, etc. (preferably circular and rectangular), and the drilling direction of the second flow holes 201 is the horizontal direction.

[0083] Among them, the equivalent diameter corresponding to the plurality of second flow holes 201 in each layer is 20 mm to 150 mm, and the number of the second flow holes 201 included in each layer is between 10 and 100. Moreover, the equivalent diameters corresponding to the plurality of second flow holes 201 in each layer can be different, and preferably the pore diameters of the plurality of second flow holes 201 located in the same layer are the same.

[0084] In one embodiment, as Figures 6 - 10 shown, the middle flow - equalizing structure 30 is a flat plate or an arc plate provided with multiple layers of flow holes, and the structural thickness of the middle flow - equalizing structure 30 is 10 mm to 300 mm.

[0085] In this embodiment, when the middle flow - equalizing structure 30 adopts the structure of a flat plate or an arc plate provided with multiple layers of flow holes, and the structural thickness of the middle flow - equalizing structure 30 is 10 mm to 300 mm, it can ensure that the fluid can be evenly distributed to each fuel assembly of the reactor core during the process of flowing back from the middle cavity of the lower chamber to the reactor core 5.

[0086] In one embodiment, as Figures 6 - 10 shown, there are 2 - 15 circles of flow holes arranged from the inside to the outside in the middle flow - equalizing structure.

[0087] In this embodiment, when the middle flow - equalizing structure 30 adopts the structure of a flat plate or an arc plate provided with multiple layers of flow holes, if its cross - section is circular and the same as the top cross - section of the lower rectifying structure 20 and the bottom cross - section of the upper diversion structure 10, 2 - 15 circles of flow holes can be arranged along the radial direction of the middle flow - equalizing structure 30 from the inside to the outside. More specifically, the number of circles of flow holes arranged in the middle flow - equalizing structure 30 is positively correlated with the radius of the middle flow - equalizing structure 30, that is, the larger the radius of the lower rectifying structure 20, the more circles of flow holes are arranged, and the smaller the radius of the middle flow - equalizing structure 30, the fewer circles of flow holes are arranged. It should be noted that in order to ensure the flow - equalizing efficiency, at least 2 layers of flow holes are arranged from top to bottom in the middle flow - equalizing structure 30.

[0088] In one embodiment, as Figures 6 - 10 shown, each of the 2 - 15 laps of flow holes in the middle flow - equalizing structure 30 includes a plurality of third flow holes 301. The equivalent diameter corresponding to the plurality of third flow holes 301 in each lap of flow holes is 20 mm to 150 mm, and the number of flow holes corresponding to the plurality of third flow holes in each layer of flow holes is 1 to 100.

[0089] In this embodiment, each layer of flow holes in the 2 - 15 laps of flow holes in the middle flow - equalizing structure 30 includes a plurality of third flow holes 301, and the shape of the second flow hole 201 can be circular, square, rectangular, oval, three - leaf plum blossom, four - leaf plum blossom or five - leaf plum blossom hole type, etc. (preferably circular).

[0090] Among them, the equivalent diameter corresponding to the plurality of third flow holes 301 in each lap is 20 mm to 150 mm, and the number of third flow holes 301 included in each layer is between 1 and 100. Moreover, the third flow hole 301 can be a through - hole with a fixed diameter, a variable - diameter hole or a stepped hole.

[0091] It can be seen that the turbulent - flow pattern control device described in the embodiment of the present application has the following beneficial effects:

[0092] 1) It can divert the fluid flowing out of the annular descending channel and entering the lower chamber, so that it flows in a channel with the same size as the original flow channel and gradually increasing size, avoiding the separation flow caused by the sudden expansion or discontinuous change of the flow channel, thus forming large turbulent vortices. In addition, flow holes are provided on the upper - layer diversion structure to guide part of the fluid to the edge position of the core inlet area, avoiding the phenomenon of low flow rate at the subsequent edge position.

[0093] 2) It can be selected according to actual needs whether the turbulent - flow pattern control device includes two structures, namely the upper - layer diversion structure and the lower - layer rectifying structure, or three structures, namely the upper - layer diversion structure, the middle flow - equalizing structure and the lower - layer rectifying structure.

[0094] 3) The lower - layer rectifying structure can control the fluid entering the middle cavity of the lower chamber. On the one hand, it restricts the velocity of the fluid to avoid the fluid having too high a velocity when changing direction (from downward flow to lateral flow) in the lower chamber, resulting in the mainstream concentrating in the middle of the lower - chamber cavity and causing uneven flow - rate distribution at the subsequent core - inlet position (larger in the middle and smaller at the edges). On the other hand, it can control the turbulent - flow pattern of the fluid to a stable stratified flow or only generate smaller - scale vortices through the flow channels formed by a plurality of small flow holes, avoiding the generation of large turbulent vortices.

[0095] 4) The middle flow - equalizing structure can rectify the fluid coming in from the lower - layer rectifying structure again before the fluid changes from lateral flow to upward flow and enters the core, evenly distributing the flow rate to each fuel assembly in the core to ensure the uniformity of the inlet flow rate of each fuel assembly in the core.

[0096] 5) By combining the three structures of the upper drainage structure, the middle flow equalization structure and the lower rectification structure, a uniform, stable, low-energy and high-frequency inlet flow rate can be provided for the reactor core (according to the aforementioned energy cascade theory of turbulence, the smaller the turbulent vortex size, the lower the energy and the higher the frequency), improving or eliminating the influence of turbulence in the front area of ​​the core inlet on the oscillation of the fuel assembly and the fluctuation of the core nuclear power, ensuring the stable output power of the reactor core and making the nuclear power plant operate safely and stably;

[0097] 6) There are many ways to install the turbulence morphology control device with other reactor components, which can be selected according to the needs of specific occasions (such as new reactor development or structural optimization of in-service power plants);

[0098] 7) The turbulence morphology control device has a relatively simple structure and does not have numerous fasteners, which can simplify the structure of the lower pile internal components and reduce the risk of parts loosening and falling.

[0099] See also Figure 7 , which is a schematic diagram of the cross-sectional structure of a reactor provided by an embodiment of the present invention. Figure 7 As shown, an embodiment of the present application further discloses a reactor, comprising a turbulence morphology control device 1 as described in any of the aforementioned embodiments.

[0100] In this embodiment, the reactor more specifically includes a reactor pressure vessel cylinder 2, an annular descending channel 3, a lower core support plate 4, a reactor core 5, a radial support key 6 and a turbulence morphology control device 1; wherein, the annular descending channel 3 is arranged in the reactor pressure vessel cylinder 2; the radial support key 6 is arranged on the inner wall of the reactor pressure vessel cylinder 2; the lower core support plate 4 is fixed in the reactor pressure vessel cylinder 2 through the radial support key 6; the top of the turbulence morphology control device 1 is connected (such as through a support ear structure) to the radial support key 6, or is fixedly connected to the bottom surface (i.e., the lower surface) of the lower core support plate 4 through a fixing part (such as a locating pin or a bolt); the reactor core 5 is arranged on the lower core support plate 4. Among them, the area in the inner cavity of the reactor pressure vessel cylinder 2 located below the lower core support plate 4 is regarded as the pressure vessel lower chamber 21; the annular descending channel 3 can be regarded as a setting surrounding the outer wall of the reactor core 5 (that is, the area between the inner wall of the reactor pressure vessel cylinder 2 and the reactor core 5).

[0101] Among them, the turbulent flow pattern control device includes an upper layer diversion structure 10 and a lower layer rectification structure 20 which are arranged in sequence from top to bottom; a plurality of water flow holes are provided in both the upper layer diversion structure 10 and the lower layer rectification structure 20; the upper layer diversion structure 10 is used to divert the fluid that enters the lower chamber from the annular downcomer 3 in the reactor; the lower layer rectification structure 20 is used to control the fluid pattern of the fluid entering the middle cavity of the lower chamber. As a first embodiment of the turbulent flow pattern control device 1, the connection mode between the upper layer diversion structure 10 and the lower layer rectification structure 20 is welding or integral molding. The turbulent flow pattern control device can be more specifically applied to the reactor pressure vessel of a pressurized water reactor, and can control the turbulent flow pattern of the reactor pressure vessel (such as the flow velocity of the fluid, the number, scale and frequency of vortices, etc.), so that the flow rate entering the reactor core inlet is uniform and stable, without large flow pulsations, and the fluid energy is low and the frequency is high. Moreover, it can also improve or eliminate the influence of the turbulence in the area before the reactor core inlet on the fuel assembly oscillation (FAO, the full name is Fuel Assembly Oscillation) and the core nuclear power fluctuation (NFF, the full name is Neutron Flux Fluctuations), ensure the core outputs power smoothly, and enable the nuclear power plant to operate safely and stably.

[0102] As a second embodiment of the turbulent flow pattern control device 1, it is different from the first embodiment in that a middle flow equalizing structure 30 is added at the junction position between the upper layer diversion structure 10 and the lower layer rectifying structure 20. That is, the turbulent flow pattern control device 1 includes an upper layer diversion structure 10 and a lower layer rectifying structure 20 arranged in sequence from top to bottom; a plurality of water flow holes are provided in both the upper layer diversion structure 10 and the lower layer rectifying structure 20; the upper layer diversion structure 10 is used to divert the fluid entering the lower chamber from the annular downcomer 3 in the reactor; the lower layer rectifying structure 20 is used to control the fluid pattern of the fluid entering the middle cavity of the lower chamber; and it further includes a middle flow equalizing structure 30, the middle flow equalizing structure 30 is arranged at the junction position between the upper layer diversion structure 10 and the lower layer rectifying structure 20, and a plurality of water flow holes are provided in the middle flow equalizing structure 30; the middle flow equalizing structure 30 is used to rectify the fluid entering the reactor core 5 of the reactor before the fluid enters from the lower layer rectifying structure 20. As a second embodiment of the turbulent flow pattern control device 1, it is different from the first embodiment in that a middle flow equalizing structure 30 is added at the junction position between the upper layer diversion structure 10 and the lower layer rectifying structure 20. That is, the bottom of the upper layer diversion structure 10 is connected to the top of the lower layer rectifying structure 20, and the middle flow equalizing structure 30 is located at the junction position between the upper layer diversion structure 10 and the lower layer rectifying structure 20, and the connection manner among the upper layer diversion structure 10, the middle flow equalizing structure 30 and the lower layer rectifying structure 20 is welding or integral molding. The turbulent flow pattern control device can be more specifically applied to the reactor pressure vessel of a pressurized water reactor, and can control the turbulent flow pattern of the reactor pressure vessel (such as the flow rate of the fluid, the number, scale and frequency of the vortices, etc.), so that the flow rate entering the reactor core inlet is uniform and stable, without large flow pulsations, and the fluid energy is low and the frequency is high. Moreover, it can also improve or eliminate the influence of the turbulence in the area before the reactor core inlet on the fuel assembly oscillation (FAO, the full name is Fuel Assembly Oscillation) and the core nuclear power fluctuation (NFF, the full name is Neutron Flux Fluctuations), ensure the stable power output of the core, and enable the nuclear power plant to operate safely and stably.

[0103] Please refer to again Figure 6 , the flow process of the fluid in the reactor (when the structure of the second embodiment of the turbulent flow pattern control device 1 is adopted) is as follows:

[0104] First, when the fluid (such as coolant) in the reactor enters the lower chamber (i.e., the lower chamber of the pressure vessel) from the reactor through the annular downcomer 3, if it is diverted through the upper diversion structure 10, the flow channel size of the fluid in the lower chamber of the reactor (i.e., the lower chamber of the pressure vessel) can be controlled, so that the fluid will not exhibit separated flow (the phenomenon that the fluid no longer adheres to the solid surface and separates from the solid surface due to a sudden increase or discontinuous change in the flow channel) when it first leaves the annular downcomer 3 and enters the lower chamber, thus avoiding the appearance of obvious large-scale vortices or vortex shedding. After that, when the fluid enters the middle cavity of the lower chamber from the lower chamber, due to the existence of the lower rectifying structure 20, the turbulent flow pattern of the fluid entering the middle cavity of the lower chamber can be controlled, and the flow pattern of the fluid is controlled to be a stable stratified flow or only generate vortices with a smaller scale (equivalent diameter less than 200 mm) through multiple small flow channels, avoiding the generation of large turbulent vortices (which may generate high hydraulic excitation and frequencies close to the natural frequency of the fuel assembly) during the process of the fluid changing direction in the lower chamber. Finally, when the fluid flows back from the middle cavity of the lower chamber into the reactor core 5, the laterally flowing fluid has been changed into an upward flowing fluid. If it also passes through the secondary rectification of the middle flow equalizing structure 30, the flow rate of the fluid is evenly distributed to each fuel assembly of the reactor core.

[0105] In summary, the embodiment of the present invention provides a turbulent flow pattern control device and a reactor. The turbulent flow pattern control device is applied to the reactor and includes an upper diversion structure, a middle flow equalizing structure, and a lower rectifying structure arranged in sequence from top to bottom; a plurality of water flow holes are provided in the upper diversion structure, the middle flow equalizing structure, and the lower rectifying structure; the upper diversion structure is used to divert the fluid that enters the lower chamber from the annular downcomer in the reactor; the lower rectifying structure is used to control the fluid pattern of the fluid entering the middle cavity of the lower chamber; the middle flow equalizing structure is used to rectify the fluid entering the reactor core of the reactor before the fluid enters the reactor core from the lower rectifying structure. The above-mentioned turbulent flow pattern control device can not only control the turbulent flow pattern of the reactor pressure vessel, make the flow rate at the inlet of the reactor core uniform and stable, without large flow pulsations, the fluid energy is low and the frequency is high; but also can improve or eliminate the influence of the turbulence in the area before the inlet of the reactor core on the oscillation of the fuel assembly and the fluctuation of the core nuclear power, ensure the core outputs power smoothly, and enable the nuclear power plant to operate safely and stably.

[0106] The above is only the specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A turbulence morphology control device, applied to a reactor, characterized in that: It comprises an upper drainage structure and a lower rectification structure which are arranged in sequence from top to bottom; a plurality of water flow holes are arranged in the upper drainage structure and the lower rectification structure; the upper drainage structure is used for draining the fluid entering the lower chamber from the annular descending channel in the reactor; the lower rectification structure is used for controlling the fluid morphology of the fluid entering the middle cavity of the lower chamber.

2. The turbulence pattern control device according to claim 1, characterized in that: It also includes a middle flow balancing structure, which is arranged at the intersection of the upper drainage structure and the lower rectifying structure, and a plurality of water flow holes are arranged in the middle flow balancing structure; the middle flow balancing structure is used to rectify the fluid entering from the lower rectifying structure before entering the reactor core of the reactor.

3. The turbulence pattern control device according to claim 1, characterized in that: The ratio between the width of the channel between the upper drainage structure and the wall surface of the lower chamber of the pressure vessel of the reactor and the width of the annular descending channel of the reactor is 0.5-3.

4. The turbulence pattern control device according to claim 1, characterized in that: The height of the upper drainage structure is 10% to 80% of the distance between the lower support plate of the reactor core and the bottom of the lower chamber of the pressure vessel.

5. The turbulence pattern control device according to claim 1, characterized in that: The upper drainage structure is partially hemispherical, semi-ellipsoidal, conical or butterfly-shaped, and the wall thickness of the upper drainage structure is 10 mm to 150 mm.

6. The turbulence pattern control device according to any one of claims 1 to 5, characterized in that: The upper drainage structure is provided with 2-8 layers of water flow holes from top to bottom.

7. The turbulence pattern control device according to claim 6, characterized in that: Each layer of water flow holes in the 2-8 layers of water flow holes in the upper drainage structure includes a plurality of first water flow holes, and the equivalent diameter corresponding to the plurality of first water flow holes in each layer of water flow holes is 20 mm to 150 mm.

8. The turbulence pattern control device according to claim 1, characterized in that: The lower rectifying structure is a cylindrical thin-walled structure, and the top of the lower rectifying structure is connected to the bottom of the upper drainage structure.

9. The turbulence pattern control device according to claim 1, characterized in that: The height of the lower rectifying structure is 10% to 80% of the distance between the lower support plate of the reactor core and the bottom of the lower chamber of the pressure vessel.

10. The turbulence pattern control device according to claim 9, characterized in that: The sum of the height of the lower rectifying structure and the height of the upper drainage structure is less than the distance between the lower support plate of the reactor core and the bottom of the lower chamber of the pressure vessel.

11. The turbulence pattern control device according to claim 10, characterized in that: The distance between the bottom of the lower rectifying structure and the wall surface of the lower chamber of the pressure vessel is greater than 0.

12. The turbulence pattern control device according to claim 1, characterized in that: The wall thickness of the lower rectifying structure is 10 mm to 150 mm.

13. The turbulence pattern control device according to any one of claims 8 to 12, characterized in that: The lower rectifying structure is provided with 2-8 layers of water flow holes from top to bottom.

14. The turbulence pattern control device according to claim 13, characterized in that: Each layer of water flow holes in the 2-8 layers of water flow holes in the lower rectifying structure includes a plurality of second water flow holes, and the equivalent diameters corresponding to the plurality of second water flow holes in each layer of water flow holes are 20 mm to 150 mm.

15. The turbulence pattern control device according to claim 2, characterized in that: The middle flow-evening structure is a flat plate or an arc plate with multiple layers of water flow holes, and the structure thickness of the middle flow-evening structure is 10 mm to 300 mm.

16. The turbulence pattern control device according to claim 15, characterized in that: The middle flow equalizing structure is provided with 2-15 circles of water flow holes from the inside to the outside.

17. The turbulence pattern control device according to claim 16, characterized in that: Each of the 2-15 circles of water flow holes in the middle flow equalizing structure includes a plurality of third water flow holes, and the equivalent diameter corresponding to the plurality of third water flow holes in each circle of water flow holes is 20 mm to 150 mm.

18. The turbulence pattern control device according to claim 17, characterized in that: The number of water flow holes corresponding to the third water flow holes in each circle of water flow holes of the middle flow equalizing structure is 1 to 100.

19. A reactor, characterized in that: It comprises a turbulence morphology control device as described in any one of claims 1 to 18.

20. The reactor according to claim 19, characterized in that It also includes a reactor pressure vessel cylinder, an annular descending channel, a lower core support plate, a reactor core and radial support keys; wherein the annular descending channel is arranged in the reactor pressure vessel cylinder; the radial support keys are arranged on the inner wall of the reactor pressure vessel cylinder; the lower core support plate is fixed in the reactor pressure vessel cylinder through the radial support keys; the top of the turbulence morphology control device is connected to the radial support keys, or is fixedly connected to the bottom surface of the lower core support plate through fixing parts; the reactor core is arranged on the lower core support plate.

Images