Reactor head structure and head system

Abstract

A reactor head structure and a head system, the reactor head structure (1) comprising a seismic support ring (30) and a seismic plate (40), wherein the seismic plate (40) is mounted in the seismic support ring (30). The reactor head structure further comprises a bracket (10), and a flow baffle (50) for dispersing high-temperature air at the center of a reactor head, wherein the bracket (10) comprises a plurality of support rods (11) arranged at intervals, and one end of each of the support rods (11) is fixed to the seismic support ring (30); and the flow baffle (50) is arranged on the seismic plate (40). The reactor head structure (1) has a simple structure and satisfies an overall seismic strength, facilitates integrated hoisting, allows for convenient maintenance, and is light in terms of weight. Moreover, cooling is realized by means of the natural circulation of air, thereby preventing unplanned emergency reactor shutdown due to burnout of cables.

Description

Reactor top structure and top system Technical Field

[0001] The present application relates to the field of reactor technology, and in particular to a reactor top structure and a reactor top system. Background Art

[0002] In a nuclear power plant, the reactor top assembly is a critical component of the reactor system. Installed above the reactor pressure vessel head, it remains fixed to the head during normal operation. During shutdowns and refueling, it is hoisted and lowered together with the reactor pressure vessel head and control rod drive mechanism. However, due to the high-temperature heat source within the control rod drive mechanism, the high-temperature airflow generated by it makes it difficult for heat to dissipate from the reactor top. This results in excessively high ambient temperatures for components within the reactor top, such as cables, posing the risk of burnout and an unplanned emergency shutdown.

[0003] To address this issue, existing reactor roof structures are equipped with forced ventilation cooling devices. However, this device occupies a significant amount of space, complicating the structure and increasing the difficulty of layout and cabling, as well as operational and maintenance costs. Furthermore, the reactor roof is overly dependent on this device, and if it fails to function properly, it could lead to a potential emergency, unplanned shutdown.

[0004] Currently, existing reactor top structures include both distributed and integrated types. The distributed reactor top structure incorporates seismic support assemblies to provide seismic support for the control rod drive mechanism. Because the structure is distributed, the seismic support assemblies require multiple seismic tie rods for connection and fixation. However, the separate, distributed structure of the seismic tie rods means that each lifting and lowering of the tie rods occupies the critical path for refueling and overhaul, making it impossible to hoist the entire reactor top structure and increasing the radiation dose to operators. The integrated reactor top structure is cylindrical in shape, significantly increasing the weight of the reactor top. The lack of corresponding seismic tie rods makes seismic design more difficult. The cylindrical structure encloses the control rod drive mechanism, forced ventilation cooling system piping, instrumentation, instrument sockets, and other equipment, significantly increasing the difficulty of in-service maintenance and replacement. Summary of the Invention

[0005] The technical problem to be solved by the present application is to provide a reactor top structure and a reactor top system.

[0006] This application adopts the following technical solutions:

[0007] A reactor top structure is constructed, comprising a seismic support ring and a seismic plate, wherein the seismic plate is installed in the seismic support ring, and further comprising:

[0008] The bracket includes a plurality of support rods arranged at intervals, one end of each support rod being fixed to the anti-seismic support ring;

[0009] A guide baffle is used to disperse the high-temperature air at the center of the stack top, and the guide baffle is arranged on the anti-seismic plate.

[0010] In some embodiments, the bracket further includes a plurality of connecting members, and both ends of the connecting members are respectively fixed to any two adjacent support rods.

[0011] In some embodiments, the connecting members include a plurality of horizontally arranged first connecting members and a plurality of inclined second connecting members, the supporting rods are all vertically arranged, and a plurality of first connecting members and a plurality of second connecting members are spaced apart between any two adjacent supporting rods, and the first connecting members and the second connecting members between any two adjacent supporting rods are cross-arranged.

[0012] In some embodiments, the support rods are evenly spaced along the circumference of the seismic support ring, the first connecting member and the second connecting member are both rod-shaped, and each adjacent first connecting member and the second connecting member defines a right triangle with the support rod.

[0013] In some embodiments, the reactor top structure further includes a base, and the other end of the support rod is fixed on the base.

[0014] In some embodiments, the base includes a base body, which is in the shape of a flange ring, and its upper end and lower end both protrude outward along the circumferential direction.

[0015] In some embodiments, the guide baffle is coaxially arranged with the anti-seismic plate.

[0016] In some embodiments, the distance between the guide baffle and the anti-seismic plate is 0-400 mm.

[0017] In some embodiments, the side length or diameter of the guide baffle is 200-2000 mm.

[0018] In some embodiments, a plurality of clearance holes for accommodating control rod drive mechanisms are formed on the guide baffle.

[0019] In some embodiments, the guide baffle is formed by splicing at least two splicing substrates, at least one clearance groove is formed on the edge of each splicing substrate, and two corresponding clearance grooves are spliced ​​to form the clearance hole.

[0020] In some embodiments, the reactor top structure further includes a cable bracket and cable bridge assembly and an upper hanger, wherein the cable bracket and cable bridge assembly is installed above the guide baffle, and the upper hanger is connected to the cable bracket and cable bridge assembly.

[0021] A reactor top system is constructed and arranged on the reactor pressure vessel top cover, comprising any of the above reactor top structures and a control rod drive mechanism.

[0022] In some embodiments, the other end of the support rod is connected to the reactor pressure vessel top cover, and the control rod drive mechanism is disposed in the reactor top structure.

[0023] In some embodiments, the reactor top structure further includes a base, the other end of the support rod is fixed on the base, and the base is mounted on the reactor pressure vessel top cover via at least one support member.

[0024] In some embodiments, the control rod drive mechanism and at least a portion of the cables arranged in the stack top system are made of high temperature resistant materials.

[0025] The implementation of this application has at least the following technical effects:

[0026] The reactor top structure constructed in the present application realizes integrated hoisting by providing a bracket, which eliminates the need for seismic tie rods to occupy the critical path of refueling overhaul, and also avoids forming a closed loop that makes maintenance and replacement difficult. This ensures that the overall seismic strength is met while the structure is simple, the integrated hoisting is convenient, maintenance is convenient, and the weight is light.

[0027] By setting up a guide baffle, the present application eliminates the need for a forced ventilation cooling device in the reactor top structure, reduces the pressure on the top space layout, reduces the difficulty of cable laying and the operation and maintenance costs, and achieves cooling through the natural circulation of air, avoiding the situation where the cables are burned and an emergency unplanned shutdown accident is caused. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solution of the present application, the present application will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and should not be considered as limiting the scope. A person of ordinary skill in the art can derive other relevant drawings based on these drawings without inventive effort. In the drawings:

[0029] FIG1 is a schematic diagram of the three-dimensional structure of a stack top system in one embodiment of the present application;

[0030] FIG2 is a schematic diagram of the assembly structure of the seismic support ring, seismic plate and guide baffle in the stack top system shown in FIG1 ;

[0031] FIG3 is a schematic diagram of the partial structure of the control rod drive mechanism and the rod control and rod position system in the stack top system shown in FIG1 . DETAILED DESCRIPTION

[0032] To provide a clearer understanding of the technical features, objectives, and effects of this application, specific embodiments of this application are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by terms such as "front," "back," "up," "down," "left," "right," "vertical," "horizontal," "bottom," "inside," "inner," and "outside" are based on the directions or positional relationships shown in some of the accompanying drawings and are constructed and operated in specific directions. These directions are intended solely to facilitate the description of this technical solution and do not necessarily require the devices or components indicated to have specific directions. Therefore, they should not be construed as limitations on this application.

[0033] It should also be noted that, unless otherwise clearly specified and limited, terms such as "installed", "connected", "connected", "fixed", and "set" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may be one or more intervening elements. The terms "first", "second", etc. are only for the convenience of describing the present technical solution, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of such features. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0034] In the following description, specific details such as specific system structures and techniques are provided for purposes of illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obscuring the description of the present application with unnecessary detail.

[0035] Figure 1 shows a reactor top structure 1 in one embodiment of the present application. This structure provides seismic support for the control rod drive mechanism (CRDM) 3. It limits excessive deformation of the CRDM during earthquakes, maintaining its normal function and ensuring its functional integrity in accident conditions. It also provides cooling and ventilation channels for the yoke coils of the CRDM 3 to ensure proper operation of the CRDM 3. The reactor top structure 1 is positioned above the reactor pressure vessel head 2 and is hoisted integrally with the reactor pressure vessel head 2 and the CRDM 3 during reactor refueling and maintenance.

[0036] The reactor top structure 1 comprises a support 10, a seismic support ring 30, a seismic plate 40, a flow guide baffle 50, a cable bracket and cable bridge assembly 60, and an upper sling 70. The support 10 includes a plurality of spaced support rods 11, each of which is fixed to the seismic support ring 30 at one end and connected to the reactor pressure vessel top cover 2 at the other end. The seismic plate 40 is plate-shaped and installed within the seismic support ring 30. The flow guide baffle 50 is installed on the seismic plate 40 to disperse the high-temperature air at the center of the reactor top, preventing direct contact between the high-temperature air and the cables in the center of the reactor top, which could cause localized high temperatures and damage the cables. The cable bracket and cable bridge assembly 60 is installed above the flow guide baffle 50 to route all of the rod control and rod position system cables 4, the core measurement system cables, loose components, and the vibration monitoring system cables in the reactor top area to the designated civil engineering interfaces. The upper lifting device 70 is connected to the cable bracket and cable bridge assembly 60 and is used to lift the reactor top structure 1 during reactor refueling and maintenance.

[0037] The multiple support rods 11 of the bracket 10 are all longitudinally shaped and spaced apart. Both ends of each support rod 11 are connected to the seismic support ring 30 and the reactor pressure vessel top cover 2 for seismic support. They also serve as lower suspension rods during the hoisting process, enabling integrated hoisting. The bracket 10 also includes multiple connectors, each of which is fixed at both ends to any two adjacent support rods 11 to increase the support strength of the bracket 10. The bracket 10 structure not only provides space for the control rod drive mechanism 3, but also provides sufficient rigidity for the reactor pressure vessel top cover 2 and the control rod drive mechanism 3 under seismic conditions, preventing the control rod drive mechanism 3 from excessively deforming to maintain its normal function. It also ensures natural cooling and ventilation of the top area of ​​the stack to prevent the local temperature in the top area from being too high and difficult to dissipate.

[0038] In some embodiments, each support rod 11 is vertically disposed between the seismic support ring 30 and the reactor pressure vessel top cover 2. The connector includes a first connector 12 and a second connector 13, wherein the first connector 12 is disposed horizontally and the second connector 13 is disposed at an angle, to prevent device failure in the event of a left-right swaying earthquake, thereby further improving the stability of the reactor top structure 1. At least one first connector 12 and at least one second connector 13 are disposed between any two adjacent support rods 11, and the ends of each first connector 12 and second connector 13 are respectively connected to two adjacent support rods 11.

[0039] Specifically, a plurality of first connecting members 12 and a plurality of second connecting members 13 may be provided between any two adjacent supporting rods 11 , and the first connecting members 12 and the second connecting members 13 between any two adjacent supporting rods 11 are alternately provided.

[0040] In this embodiment, the support rods 11 are evenly spaced along the circumference of the anti-seismic support ring 30, such that each support rod 11 is connected to both sides by a plurality of first connecting members 12 and second connecting members 13. Furthermore, each adjacent first connecting member 12 and second connecting member 13 defines a right triangle with the support rod 11.

[0041] It should be understood that the “adjacent” here means that the first connecting member 12 and the second connecting member 13 between two adjacent support rods 11 are adjacent to each other in upper and lower directions.

[0042] In some embodiments, the support rods 11 can be made of square steel or round steel, and the number thereof is preferably 6-10, and the side length (for support rods 11 made of square steel) or diameter (for support rods 11 made of round steel) thereof is preferably 30 mm-200 mm.

[0043] In some embodiments, there are preferably 5-10 first connecting members 12 and 5-10 second connecting members 13 between any two adjacent support rods 11. The first connecting members 12 and / or the second connecting members can be made of angle steel or flat steel, and their width is preferably 30mm-150mm.

[0044] In some embodiments, the bracket 10 can also be replaced with a pull rod structure.

[0045] In some embodiments, the reactor top structure 1 further includes a base 20 for increasing the seismic support strength of the reactor top structure 1. Specifically, the base 20 includes a base body 21, which is flange-shaped, with both upper and lower ends protruding outward along the circumferential direction. The lower end of each support rod 11 is fixed to the upper end surface of the base body 21, which can effectively increase the seismic support rigidity, lower the center of gravity of the reactor top structure 1, reduce load (torque), and ensure that the overall weight of the reactor top structure 1 is not too large.

[0046] In some embodiments, the base 20 further includes at least one support member 22 , and the base body 21 is fixed to the reactor pressure vessel top cover 2 via the support member 22 .

[0047] In this embodiment, the number of the support members 22 can be multiple, preferably 4 to 10. The multiple support members 22 are arranged at intervals on the circumference of the lower end of the base body 21 and are all connected to the reactor pressure vessel top cover 2.

[0048] In this embodiment, the support member 22 is a skirt structure, and a plurality of support members 22 are evenly spaced and arranged on the circumference of the lower end portion of the seat body 21 .

[0049] In some embodiments, the axial height of the seat body 21 is preferably 200 mm-2000 mm.

[0050] It should be understood that the total height of the support rod 11 and the base 20 is adapted to the height of the control rod drive mechanism 3 , and the heights of the base 20 and the support rod 11 can be flexibly adjusted.

[0051] Referring to FIG. 2 , in this embodiment, the anti-seismic support ring 30 is annular, and the anti-seismic plate 40 is disc-shaped. The outer diameter of the anti-seismic plate 40 matches the inner diameter of the anti-seismic support ring 30, and the anti-seismic plate 40 is fixed within the anti-seismic support ring 30. The anti-seismic plate 40 has several accommodating holes extending through its thickness for receiving the control rod drive mechanism 3 therethrough.

[0052] It should be understood that the shapes of the anti-seismic support ring 30 and the anti-seismic plate 40 are not limited to circular, and can also be set to any shape such as square, polygon, etc. The anti-seismic support ring 30 can adopt a solid structure, and its interior can also adopt a hollow box structure.

[0053] The seismic support ring 30, seismic plate 40, bracket 10, and base 20 form a "drum-net" support structure, which offers several benefits, including but not limited to: First, this support structure achieves an integrated design for the reactor top. During hoisting and repositioning, the entire reactor top structure 1 can be hoisted and repositioned simply by rigging the upper hoist 70. This avoids the installation of multiple hoisting structures and eliminates the need to occupy the critical path for refueling overhauls, making operation easier, reducing operator radiation dose, and simplifying in-service maintenance and replacement. Second, a lightweight structure achieves a holistic seismic design, reducing the weight of the reactor top while increasing seismic margin. This structure not only supports the reactor top but also provides sufficient rigidity for the reactor top and control rod drive mechanism 3 during seismic conditions, limiting excessive deformation of the control rod drive mechanism 3 to maintain normal function and ensure its functional integrity under seismic conditions. Third, this integrated support structure enables modularization (off-island assembly and integrated hoisting) of the reactor top structure 1.

[0054] In some embodiments, the guide baffle 50 is disposed at the center of the anti-vibration plate 40 to block the high-temperature air generated by the control rod drive mechanism 3 and concentrated at the center of the stack top. This prevents the high-temperature air at the center of the stack top from directly contacting the cables at the center of the stack top, which could cause localized overheating and damage the cables. Furthermore, the guide baffle 50 can also direct the high-temperature air that rises to the center of the stack top to a secondary center, allowing the high-temperature air that originally rose from the center to diffuse circumferentially around the stack top. This extends the high-temperature air's airflow and expands its dispersion area, thereby preventing localized high temperatures and, in turn, preventing damage to the cables located at the center of the cable tray and cable bridge assembly 60 from being damaged by the high-temperature air.

[0055] It should be understood that since the high-temperature coils in the control rod drive mechanism 3 emit a large amount of heat, a heat island effect is generated in the control rod drive mechanism 3 located in the bracket 10. A large amount of high-temperature air is concentrated toward the center position (central axis position) and diffuses upward, thereby generating a local high-temperature area. Since there is a gap between the accommodating hole on the anti-seismic plate 40 and the control rod drive mechanism 3, the high-temperature air continues to rise along the accommodating hole, which will affect the cable bracket located above it and the cables arranged at the center position of the cable bridge assembly 60, causing damage to them.

[0056] Therefore, the aforementioned "center position" refers to the small area centered around the central axis of the control rod drive mechanism 3 (which, in this embodiment, is also the central axis of the reactor top structure 1, the seismic plate 40, and the seismic support ring 30). In this embodiment, this refers to the area covered by the guide baffle 50. Correspondingly, the aforementioned "sub-center position" refers to any other position not listed as the center position.

[0057] In some embodiments, the shape of the guide baffle 50 can be circular, rectangular, polygonal or other irregular shapes, and its side length (when the guide baffle 50 is rectangular) or diameter (when the guide baffle 50 is circular) is preferably 200-2000 mm.

[0058] In some embodiments, the guide baffle 50 and the anti-seismic plate 40 may be arranged in contact or spaced apart, with the distance between them preferably ranging from 0 mm to 400 mm. The reactor top structure 1 also includes a plurality of connectors (not shown) for securing the guide baffle 50 to the upper end surface of the anti-seismic plate 40. In some embodiments, these connectors may be adjustable to allow for adjustment of the distance between the anti-seismic plate 40 and the guide baffle 50. In this embodiment, these connectors are adjustment bolts.

[0059] It should be understood that the connector may also be fixed with other structures, and the distance between the guide baffle 50 and the anti-seismic plate 40 may be controlled by providing a local protruding structure between the two.

[0060] In some embodiments, the thickness of the guide baffle 50 is preferably 5 mm to 50 mm.

[0061] In some embodiments, the guide baffle 50 is further formed with a plurality of clearance holes 52 along its thickness to accommodate the upper end of the control rod drive mechanism 3. The shape and position of the clearance holes 52 are adapted to the control rod drive mechanism 3 to minimize the high-temperature airflow from passing through the clearance holes 52 and reaching the cable bracket and cable bridge assembly 60 above.

[0062] It should be understood that when the horizontal position of the upper end portion of the control rod drive mechanism 3 is lower than the horizontal position of the guide baffle 50 , the guide baffle 50 may not be provided with the clearance hole 52 .

[0063] In some embodiments, the guide baffle 50 is formed by splicing at least two spliced ​​base plates 51, and each spliced ​​base plate 51 has at least one clearance groove formed on its edge. The corresponding clearance grooves on two adjacent spliced ​​base plates 51 are spliced ​​together to form the clearance hole 52. This improves the ease of assembly and disassembly of the reactor top structure 1 and facilitates assembly and disassembly when components in the control rod drive mechanism 3 need to be replaced.

[0064] In this embodiment, the guide baffle 50 is made of metal, coaxially arranged with the anti-vibration plate 40, and has an overall rectangular shape. It is formed by splicing four splicing base plates 51, each of which is provided with a plurality of clearance grooves, and the corresponding clearance grooves are spliced ​​to form a plurality of clearance holes 52.

[0065] The provision of the guide baffle 50 has multiple beneficial effects, including but not limited to: First, it eliminates the need for a forced ventilation cooling system for the reactor top structure 1, while ensuring the overall operational performance of the control rod drive mechanism 3, reducing the probability of coil component burnout and unplanned shutdowns due to cooling and ventilation device failures, and improving the reliability and economic efficiency of nuclear power plant operation. It allows normal operation during natural ventilation cooling, both during normal reactor operation and during shutdowns for refueling. Second, the absence of a forced ventilation cooling system reduces the overall weight of the reactor top structure 1 and lowers its center of gravity. It also facilitates the routing of cables on the top of the reactor, eliminating the need to dismantle ventilation-related structures during shutdowns for refueling, thus shortening the overhaul and refueling cycle. Third, the guide baffle 50 cooperates with the support structure formed by the anti-seismic support ring 30, the anti-seismic plate 40, the bracket 10, and the base 20, ensuring that high-temperature air blocked by the guide baffle 50 is located below the guide baffle 50 and can be dissipated through natural ventilation, further improving the heat dissipation effect of the reactor top structure 1.

[0066] In some embodiments, the cable bracket and cable bridge assembly 60, the upper hanger 70, the seismic support ring 30 and the seismic plate 40 can all use existing technologies to achieve the above functions.

[0067] It should be understood that the above-mentioned “fixing” can be fixing by welding, fixing by fasteners (bolt connection or riveting), or fixing by an integrated molding process, and no specific limitation is made here.

[0068] It should be understood that the above numerical ranges all include this number.

[0069] As shown in Figure 1, the present application also constructs a top system, which is arranged on the reactor pressure vessel top cover 2, including any of the above-mentioned reactor top structures 1 and a control rod drive mechanism 3, wherein the control rod drive mechanism 3 is inserted into the reactor top structure 1.

[0070] 3 , in some embodiments, the CRDM 3 may be made of high-temperature resistant materials to improve the operating performance of the CRDM 3 and prevent it from being burned by high-temperature air.

[0071] In some embodiments, the cables in the reactor top structure 1 and at least part of the cables arranged in the cable bridge assembly 60 are also made of high-temperature resistant materials to improve the performance of the cables and prevent them from being burned by high-temperature air.

[0072] Specifically, in this embodiment, the rod control and rod position system cables 4 arranged in the cable and cable bridge assembly 60 are made of high-temperature resistant materials.

[0073] It can be understood that the above embodiments only express the preferred implementation methods of the present application, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present application. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, the above technical features can be freely combined, and several deformations and improvements can be made, which all fall within the scope of protection of the present application. Therefore, all equivalent changes and modifications made to the scope of the claims of the present application should fall within the scope of coverage of the claims of the present application.

Claims

1. A reactor top structure, comprising an anti-seismic support ring (30) and an anti-seismic plate (40), wherein the anti-seismic plate (40) is installed in the anti-seismic support ring (30), characterized in that: Also includes: A bracket (10) comprising a plurality of spaced support rods (11), one end of each support rod (11) being fixed to the anti-seismic support ring (30); A guide baffle (50) for dispersing high-temperature air at the center of the top of the stack, wherein the guide baffle (50) is arranged on the anti-vibration plate (40).

2. The reactor top structure according to claim 1, characterized in that: The bracket (10) further comprises a plurality of connecting members, and both ends of the connecting members are respectively fixed to any two adjacent support rods (11).

3. The reactor top structure according to claim 2, characterized in that: The connecting members include a plurality of horizontally arranged first connecting members (12) and a plurality of obliquely arranged second connecting members (13); the supporting rods (11) are all vertically arranged; a plurality of first connecting members (12) and a plurality of second connecting members (13) are spaced apart between any two adjacent supporting rods (11); and the first connecting members (12) and the second connecting members (13) between any two adjacent supporting rods (11) are cross-arranged.

4. The reactor top structure according to claim 2, characterized in that: The support rods (11) are evenly spaced and arranged along the circumference of the anti-seismic support ring (30); the first connecting member (12) and the second connecting member (13) are both rod-shaped; and each adjacent first connecting member (12) and second connecting member (13) define a right triangle with the support rod (11).

5. The reactor top structure according to claim 1, characterized in that: The reactor top structure further comprises a base (20), and the other end of the support rod (11) is fixed on the base (20).

6. The reactor top structure according to claim 5, characterized in that: The base (20) comprises a base body (21), and the base body (21) is in the shape of a flange ring, with an upper end and a lower end thereof both protruding outward along the circumferential direction.

7. The reactor top structure according to claim 1, characterized in that: The guide baffle (50) and the anti-vibration plate (40) are coaxially arranged.

8. The reactor top structure according to claim 1, characterized in that: The distance between the guide baffle (50) and the anti-seismic plate (40) is 0-400 mm.

9. The reactor top structure according to claim 1, characterized in that: The side length or diameter of the guide baffle (50) is 200-2000 mm.

10. The reactor top structure according to claim 1, characterized in that: A plurality of clearance holes (52) for accommodating the control rod drive mechanism (3) are formed on the guide baffle (50).

11. The reactor top structure according to claim 10, characterized in that: The guide baffle (50) is formed by splicing at least two splicing substrates (51), and at least one clearance groove is formed on the edge of each splicing substrate (51), and two corresponding clearance grooves are spliced to form the clearance hole (52).

12. The reactor top structure according to claim 1, characterized in that: The reactor top structure further comprises a cable bracket and cable bridge assembly (60) and an upper hanger (70), wherein the cable bracket and cable bridge assembly (60) is installed above the guide baffle (50), and the upper hanger (70) is connected to the cable bracket and cable bridge assembly (60).

13. A stack top system, arranged on a reactor pressure vessel top cover (2), characterized in that: It comprises the reactor top structure and the control rod drive mechanism (3) according to any one of claims 1 to 12.

14. The stack top system according to claim 13, wherein: The other end of the support rod (11) is connected to the reactor pressure vessel top cover (2), and the control rod drive mechanism (3) is inserted into the reactor top structure (1).

15. The stack top system according to claim 14, characterized in that: The reactor top structure (1) further comprises a base (20), the other end of the support rod (11) is fixed on the base (20), and the base (20) is mounted on the reactor pressure vessel top cover (2) via at least one support member (22).

16. The stack top system according to claim 13, wherein: The control rod drive mechanism (3) and at least part of the cables arranged in the stack top system are made of high temperature resistant materials.

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