A flow guide plate and a stack top structure

Abstract

This invention belongs to the field of pressurized water reactor technology, specifically relating to a deflector plate and reactor top structure. The reactor top structure includes a pressure vessel top cover, a ventilation structure, a cylindrical cofferdam assembly, a seismic support plate, and a deflector plate. The cofferdam assembly is fixedly installed on the upper end of the pressure vessel top cover. A ventilation structure is provided on the outer wall of the cofferdam assembly. The deflector plate is installed on the reactor control rod drive mechanism inside the cofferdam assembly. A flange is provided on the top of the cofferdam assembly for installing the seismic support plate. The seismic support plate is flange-shaped and is bolted to the flange on the top of the cofferdam assembly, fixing it above the cofferdam assembly. This invention solves the problems of forced convection cooling in existing pressurized water reactor tops, such as the need for electricity, noise generation, poor economic efficiency, impact on nuclear safety, difficulty in installation, poor support, and poor heat dissipation.

Description

Technical Field

[0001] This invention belongs to the field of pressurized water reactor technology, specifically relating to a flow guide plate and a reactor top structure. Background Technology

[0002] High temperatures can cause cables to overheat, which in turn affects data transmission. The function of the deflector is to prevent all high-temperature gas from flowing out from the top of the stack, and to allow the high-temperature gas to flow out from the ventilation structure at the top of the casing as much as possible. This reduces the proportion of high-temperature gas flowing out from the top, thereby lowering the hot spot temperature at the top of the stack and preventing the cables at the top of the stack from being baked by continuous high-temperature airflow, thus preventing the cables at the top from overheating.

[0003] The reactor control rod drive mechanism is cooled by natural convection at the reactor top to prevent overheating. Currently, forced convection is used both domestically and internationally to cool the reactor control rod drive mechanism. However, this method consumes a significant amount of electricity, increasing the cost of nuclear power plants and reducing their economic viability. Secondly, forced convection inevitably requires numerous fans, which generate considerable noise, potentially affecting the accuracy of certain detectors. Furthermore, if the nuclear power plant loses all power, the fans will stop operating, and the reactor control rod drive mechanism will not receive the necessary cooling, leading to overheating and a decline in its performance.

[0004] In the prior art, a truss-type integrated reactor top structure suitable for high-temperature drive mechanisms uses a frame-type conduit for better heat dissipation. However, while this conduit structure provides good heat dissipation at the reactor top, it has disadvantages such as difficulty in installation and poor support. In addition, the integrated reactor top and shielding plate of the pressurized water reactor use a highly sealed conduit. However, because this conduit is too tightly sealed to the reactor control rod drive mechanism, the heat of the control rod drive mechanism inside the conduit cannot be effectively dissipated. The high-temperature gas generated after cooling the control rod drive mechanism will also continuously bake the cables and other equipment. Therefore, both of the above patents have obvious disadvantages. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a flow guide plate and a reactor top structure that can solve the problems of forced convection cooling in the reactor top of existing pressurized water reactors, such as the need to provide electricity, noise generation, poor economic efficiency, impact on nuclear power safety, difficulty in installation, poor support, and poor heat dissipation.

[0006] The technical solution adopted in this invention is as follows:

[0007] A flow deflector includes six mounting plates: a first mounting plate, a second mounting plate, a third mounting plate, a fourth mounting plate, a fifth mounting plate, and a sixth mounting plate. These six types of plates are arranged in layers from top to bottom. The second, third, fourth, and sixth mounting plates are located on the top layer, with the sixth mounting plate being a square structure. The first mounting plate is located on the second layer and is a fan-shaped structure located at the four corners. Below the first mounting plate are several layers, each containing a fifth mounting plate. The flow deflector, when viewed from above, has a circular structure with a higher outer edge and a lower center.

[0008] One end of the No. 2, No. 3, and No. 4 mounting plates is fitted to the internal shape of the casing.

[0009] Each of the No. 1, No. 2, No. 3, No. 4, No. 5, and No. 6 mounting plates has a through hole at its center. The position of the through hole corresponds to the drive mechanism of each reactor control rod, and the diameter of the through hole is the same as the outer diameter of the reactor control rod drive mechanism.

[0010] A gap is left between adjacent mounting plates to compensate for thermal expansion.

[0011] The distance between the upper surface of the No. 6 mounting plate of the deflector and the upper surface of the casing is 510mm; the No. 5 mounting plate and the No. 1 mounting plate are parallel and the distance between their upper surfaces and the upper surface of the casing is 498mm. The upper surface of the outer ring of the deflector is 12mm higher than the upper surface of the adjacent inner ring of the deflector. The height of the upper surface decreases by 12mm from the outside to the inside, and is lowest at the center. The distance between the upper surface of the No. 5 mounting plate at the center and the upper surface of the casing is 570mm.

[0012] A reactor top structure includes a pressure vessel top cover, a ventilation structure, a cylindrical confining assembly, a seismic support plate, and a flow guide plate as described in claim 5. The confining assembly is fixedly installed on the upper end of the pressure vessel top cover. The ventilation structure is provided on the outer wall of the confining assembly. The flow guide plate is installed on the reactor control rod drive mechanism inside the confining assembly. A flange is provided on the top of the confining assembly for installing the seismic support plate. The seismic support plate is flange-shaped and is bolted to the flange on the top of the confining assembly, thus fixing it above the confining assembly.

[0013] The ventilation structure is divided into upper and lower parts. Cooling air is sent into the interior of the casing assembly from the lower ventilation structure. The cooling air is used to cool the control rod drive mechanism. The high-temperature gas generated after heating is discharged from the upper ventilation structure.

[0014] The outer diameter of the guide plate is smaller than the inner diameter of the casing, and the through hole is fitted onto the reactor control rod drive mechanism.

[0015] The guide plate is located slightly above the middle of the upper ventilation structure, and a supporting angle steel structure is set on the inner side of the upper ventilation structure. The guide plate is installed on the supporting angle steel.

[0016] It also includes a seismic plate and a shielding plate. The seismic plate is located above the flow guide plate, and the shielding plate is located above the seismic plate. The shielding plate also serves as a cover plate for the inner hole of the seismic support plate. It also includes a cable bracket fixed directly above the seismic support plate. One end of the cable bracket that connects to the seismic support plate is located outside the shielding plate, and its position is directly above the seismic support plate.

[0017] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0018] (1) The baffle and top structure provided by the present invention use natural convection to cool the reactor control rod drive mechanism, which has good economy, quietness and safety; the addition of the baffle makes better use of the heat dissipation function of the vent of the casing and significantly reduces the temperature of the hot spot area at the top of the reactor.

[0019] (2) The present invention provides a flow guide plate and a reactor top structure, which adopts a structure setting of fixing the flow guide plate to the reactor control rod drive mechanism. When the high temperature gas flows upward, the flow guide plate can not only prevent the high temperature gas from flowing upward, but also guide the blocked high temperature gas to the outlet of the casing.

[0020] (3) The guide plate provided by the present invention has the advantages of simple structure and easy processing, manufacturing and installation.

[0021] (4) The flow guide plate and stack top structure provided by the present invention have both good support and excellent heat dissipation performance, which well meet the needs of reducing cable hot spots, while ensuring the integration of the stack top structure. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A front view of a baffle provided by the present invention;

[0024] Figure 2 A schematic diagram of the overall structure of a guide vane provided by the present invention;

[0025] Figure 3A schematic diagram of the overall structure of a top structure for achieving natural convection cooling provided by the present invention;

[0026] Figure 4 A partial structural diagram of a top structure for achieving natural convection cooling, provided by the present invention;

[0027] In the diagram: 1. Pressure vessel top cover, 2. Ventilation structure, 3. Enclosure, 4. Seismic support plate, 5. Cable tray, 6. Reactor control rod drive mechanism, 7. Flow guide plate, 8. Shielding plate, 9. Seismic plate, 10. Mounting plate No. 1, 11. Mounting plate No. 2, 12. Mounting plate No. 3, 13. Mounting plate No. 4, 14. Mounting plate No. 5, 15. Mounting plate No. 6, 16. Through hole. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] like Figure 1 and Figure 2As shown, the present invention provides a guide plate comprising a first mounting plate 10, a second mounting plate 11, a third mounting plate 12, a fourth mounting plate 13, a fifth mounting plate 14, and a sixth mounting plate 15. These six types of plates are arranged in layers from top to bottom. The second mounting plate 11, third mounting plate 12, fourth mounting plate 13, and sixth mounting plate 15 are located on the top layer. One end of the second mounting plate 11, third mounting plate 12, and fourth mounting plate 13 conforms to the internal shape of the surrounding cylinder. The sixth mounting plate 15 has a square structure. The first mounting plate 10 is located on the second layer and has a fan-shaped structure located at the four corners. Below the first mounting plate 10 are several layers, each with a fifth mounting plate 14.

[0032] Mounting plates 10, 11, 12, 13, 14, and 15 each have through holes 16 at their center. The positions of the through holes 16 correspond to the reactor control rod drive mechanisms 6, and the diameter of the through holes 16 is the same as the outer diameter of the reactor control rod drive mechanism 6.

[0033] The arranged baffle is a circular structure when viewed from above, with a high outer edge and a low center. When the high-temperature gas flows upward, the baffle not only prevents the high-temperature gas from flowing upward, but also guides the blocked high-temperature gas to the outlet of the casing.

[0034] The left and right adjacent mounting plates of the guide vane have a certain gap to compensate for thermal expansion; the upper surface of the sixth mounting plate 15 of the guide vane is 510mm away from the upper surface of the casing 3. The fifth mounting plate 14 and the first mounting plate 10 are parallel and their upper surfaces are 498mm away from the upper surface of the casing 3. The upper surface of the outer ring of the guide vane 7 is 12mm higher than the upper surface of the adjacent inner ring of the small plate. The height of the upper surface decreases by 12mm from the outside to the inside, and is lowest at the center. The upper surface of the fifth mounting plate 14 at the center is 570mm away from the upper surface of the casing 3.

[0035] like Figure 3 and Figure 4As shown, the present invention provides a reactor top structure including a pressure vessel top cover 1, a ventilation structure 2, a cylindrical confining assembly 3, a seismic support plate 4, a cable tray 5, a reactor control rod drive mechanism 6, a shielding plate 8, a seismic plate 9, and a flow guide plate 7. The confining assembly 3 is fixedly installed on the upper end of the pressure vessel top cover 1. To facilitate air cooling of the control rod drive mechanism 6, a ventilation structure 2 is provided on the outer wall of the confining assembly 3. The ventilation structure 2 is divided into upper and lower parts. Cooling air is sent into the interior of the confining assembly 3 from the lower ventilation structure 2. The cooling air is used to cool the control rod drive mechanism 6. The high-temperature gas generated after heating is discharged from the upper ventilation structure 2.

[0036] The guide plate 7 is installed inside the casing assembly 3. The outer diameter of the guide plate 7 is smaller than the inner diameter of the casing 3. It is installed on the reactor control rod drive mechanism 6. The guide plate 7 is also provided with a plurality of through holes 16 that pass through the upper and lower ends of the guide plate. The through holes 16 are fitted onto the reactor control rod drive mechanism 6. The through holes 16 are used to ensure the cooperation relationship between the reactor control rod drive mechanism 6 and the guide plate 7.

[0037] The guide plate 7 is located slightly above the center of the upper ventilation structure 2. A supporting angle steel structure is provided on the inner side of the upper ventilation structure 2, and the guide plate 7 is installed on the supporting angle steel, thus installing the guide plate 7 on the inner side of the upper ventilation structure 2. The guide plate 7 can both block the cooling air below and facilitate the installation and replacement of the single control rod drive mechanism 6.

[0038] The top of the casing assembly 3 is provided with a flange for installing the seismic support plate 4.

[0039] The seismic support plate 4 is flange-shaped, and the seismic support plate 4 is bolted to the top flange of the casing assembly 3 and fixed above the casing assembly 3.

[0040] It also includes a shock-absorbing plate 9 and a shielding plate 8. The shock-absorbing plate 9 is located above the flow guide plate 7, and the shielding plate 8 is located above the shock-absorbing plate 9. The shielding plate 8 serves as a cover plate for the inner hole of the shock-absorbing support plate 4.

[0041] To facilitate centralized cable laying and easy connection between the cable and each control rod drive mechanism 6, a cable bracket 5 is also included, which is fixed directly above the seismic support plate 4. The end of the cable bracket 5 that connects to the seismic support plate 4 is located outside the shielding plate 8, and its position is directly above the seismic support plate 4.

[0042] The guide plate 7 is made of carbon structural steel or stainless steel.

[0043] The outer side of the casing assembly 3 is provided with six cable troughs. The temperature of the cables inside the cable troughs must not exceed the specified temperature. Therefore, high-temperature gas must not accumulate in the area inside the casing corresponding to the cable troughs. The guide plate 7 will have a gap here to prevent the accumulation of high-temperature gas in the area near the cable troughs on the inner side of the casing and reduce the hot spots of the cable troughs.

[0044] In this invention, the reactor top will adopt a natural convection cooling method. Specifically, cold air enters the reactor top 3 from the ventilation structure 2 at the bottom of the reactor top 3. When the cold air flows over the surface of the reactor control rod drive mechanism 6, it carries away the heat on the reactor control rod drive mechanism 6 through convection heat transfer. The heated gas flows upward due to the density difference. When the rising high-temperature gas reaches a certain height, it will encounter the guide plate 7. After encountering the guide plate 7, the high-temperature gas will flow along the geometric shape of the guide plate 7. At this time, the high-temperature gas is being guided by the guide plate. The guided high-temperature gas will be discharged from the ventilation structure 2 at the top of the reactor top 3. The reactor top 3, ventilation structure 2, and guide plate 7 mentioned above are all indispensable. For example, if the guide plate 7 is missing, a large amount of high-temperature gas flow will flow out from the top of the reactor top, which will cause the cables at the top of the reactor top to overheat. Therefore, the guide plate 7 is used to discharge most of the high-temperature gas flow from the ventilation structure 2 at the top of the reactor top 3, ensuring the normal use of the cables. Furthermore, cold air must enter the enclosure from the lower ventilation structure 2 of the enclosure 3, and be heated by the control rod drive mechanism 6 to create a density difference, driving the gas upward and thus achieving natural circulation. If cold air enters the enclosure from the upper ventilation structure 2 of the enclosure 3, the control rod drive mechanism 6 will not receive the necessary cooling, and the guide plate 7 will not function at all.

[0045] In traditional technology, the reactor control rod drive mechanism uses forced convection. This method has a high inlet air velocity, a short residence time in the reactor top, and a small gas temperature rise. Therefore, the outlet gas does not affect the use of cables. However, its disadvantages are obvious: high power consumption, poor economic efficiency, noise generation, and the requirement for electricity.

[0046] This invention employs natural convection cooling, which offers several significant advantages over existing reactor top cooling methods. Firstly, natural convection cooling requires no electricity, thus reducing power consumption and increasing the economic efficiency of the nuclear power plant. Secondly, compared to forced convection systems that require numerous fans, generating significant noise that can affect the accuracy of certain detectors, this natural convection cooling method provides excellent quietness. Finally, even when the nuclear power plant loses all power, the novel reactor top design ensures that the reactor control rod drive mechanism 6 receives the necessary cooling, guaranteeing the safe operation of the nuclear power plant.

[0047] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0048] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A deflector plate, characterized in that, The system includes six types of mounting plates: No. 1 mounting plate (10), No. 2 mounting plate (11), No. 3 mounting plate (12), No. 4 mounting plate (13), No. 5 mounting plate (14), and No. 6 mounting plate (15). These six types of mounting plates are arranged in layers from top to bottom. Mounting plates No. 2 (11), No. 3 (12), No. 4 (13), and No. 6 (15) are located on the top layer. Mounting plate No. 6 (15) has a square structure. Mounting plate No. 1 (10) is located on the second layer. Mounting plate No. 1 (10) has a fan-shaped structure and is located at the four corners. Below mounting plate No. 1 (10) are several layers, each with mounting plate No. 5 (14). The arranged guide plate has a circular structure when viewed from above, and it has a structure that is high on the outside and low in the center. One end of the No. 2 mounting plate (11), No. 3 mounting plate (12), and No. 4 mounting plate (13) is matched with the internal shape of the casing. The No. 1 mounting plate (10), No. 2 mounting plate (11), No. 3 mounting plate (12), No. 4 mounting plate (13), No. 5 mounting plate (14), and No. 6 mounting plate (15) all have through holes (16) at their center. The positions of the through holes (16) correspond to the reactor control rod drive mechanisms (6), and the diameter of the through holes (16) is the same as the outer diameter of the reactor control rod drive mechanism (6).

2. The guide vane according to claim 1, characterized in that, A gap is left between adjacent mounting plates to compensate for thermal expansion.

3. The guide vane according to claim 2, characterized in that, The distance between the upper surface of the No. 6 mounting plate (15) of the guide vane and the upper surface of the casing is 510mm; the No. 5 mounting plate (14) and the No. 1 mounting plate (10) are parallel and the distance between their upper surfaces and the upper surface of the casing is 498mm. The upper surface of the outer ring plate of the guide vane (7) is 12mm higher than the upper surface of the adjacent inner ring plate. The height of the upper surface decreases by 12mm from the outside to the inside, and is lowest at the center. The distance between the upper surface of the No. 5 mounting plate (14) at the center and the upper surface of the casing is 570mm.

4. A stack top structure, characterized in that, The device includes a pressure vessel top cover (1), a ventilation structure (2), a cylindrical confining assembly (3), a seismic support plate (4), and a flow guide plate (7) as described in claim 3. The confining assembly (3) is fixedly installed on the upper end of the pressure vessel top cover (1). The ventilation structure (2) is provided on the outer wall of the confining assembly (3). The flow guide plate (7) is installed on the reactor control rod drive mechanism (6) inside the confining assembly (3). A flange is provided on the top of the confining assembly (3) for installing the seismic support plate (4). The seismic support plate (4) is flange-shaped. The seismic support plate (4) and the flange on the top of the confining assembly (3) are connected by bolts and fixed above the confining assembly (3).

5. The stack top structure according to claim 4, characterized in that, The ventilation structure (2) is divided into upper and lower parts. Cooling air is sent into the interior of the casing assembly (3) from the lower ventilation structure (2). The cooling air is used to cool the control rod drive mechanism (6). The high-temperature gas generated after heating is discharged from the upper ventilation structure (2).

6. The stack top structure according to claim 4, characterized in that, The outer diameter of the guide plate (7) is smaller than the inner diameter of the casing (3), and the through hole (16) is fitted onto the reactor control rod drive mechanism (6).

7. The stack top structure according to claim 5, characterized in that, The guide plate (7) is located slightly above the middle of the upper ventilation structure (2). A supporting angle steel structure is set on the inner side of the upper ventilation structure (2), and the guide plate (7) is installed on the supporting angle steel.

8. The stack top structure according to claim 4, characterized in that, It also includes a seismic plate (9) and a shielding plate (8). The seismic plate (9) is located above the guide plate (7), and the shielding plate (8) is located above the seismic plate (9). The shielding plate (8) serves as a cover plate for the inner hole of the seismic support plate (4). It also includes a cable bracket (5) fixed directly above the seismic support plate (4). One end of the cable bracket (5) connected to the seismic support plate (4) is located outside the shielding plate (8), and its position is directly above the seismic support plate (4).

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