Reactor cavity water injection runner structure and reactor building

Abstract

The invention discloses a reactor cavity water injection runner structure and a reactor building, which can reduce the design and maintenance difficulty of the reactor cavity water injection runner structure and improve the reliability of the reactor cavity water injection runner structure. The reactor cavity water injection runner structure comprises an annular main shielding wall (1), a water injection runner (2) and an anti-falling grating assembly. The water injection runner (2) is formed in the annular main shielding wall (1) and is used for communicating a reactor cavity with a reactor pit. The anti-falling grating assembly comprises an anti-falling grating (3), a driving part and a detection control part. And the anti-falling grating (3) is arranged at an opening at the upper end of the water injection runner (2). And the driving component is connected with the anti-falling grid (3). The detection control part is electrically connected with the driving part and used for detecting whether cooling water exists on the top face of the annular main shielding wall (1) or not and controlling the driving part to act according to the detection result so that the anti-falling grating (3) can be opened or closed.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear power, and in particular relates to a reactor cavity water injection flow channel structure and a reactor building. Background Art

[0003] In a nuclear power plant, after a serious accident occurs, the cooling water in the injection tank needs to be injected into the reactor cavity and then introduced into the reactor pit to dissipate the heat of the reactor core melt and prevent the pressure vessel from being melted through.

[0004] Currently, the technology used for reactor pit injection in reactor buildings that have been built or are under construction mostly uses process pipelines. The process pipelines connect the injection tank and the reactor pit inside the reactor, which makes the design of the process pipelines complex. The process pipelines also involve systematic and comprehensive issues such as maintenance during the construction period and replacement of wearing parts (such as valves). The operation and maintenance during the entire life cycle is difficult and the reliability is not ideal. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a reactor cavity water injection flow channel structure and a reactor building in view of the above-mentioned deficiencies in the prior art, which can reduce the difficulty of designing and maintaining the reactor cavity water injection flow channel structure and improve the reliability of the reactor cavity water injection flow channel structure.

[0006] In the first aspect, an embodiment of the present invention provides a reactor cavity water injection flow channel structure, which includes an annular main shielding wall, a water injection flow channel and an anti-drop grid assembly. The annular main shielding wall is located between the reactor cavity and the reactor pit in the containment. The water injection flow channel is opened inside the annular main shielding wall, and is used to connect the reactor cavity and the reactor pit, so that the cooling water flowing into the reactor cavity can flow into the reactor pit through the water injection flow channel. The anti-drop grid assembly includes an anti-drop grid, a driving component and a detection control component. The anti-drop grid is arranged at the upper end opening of the water injection flow channel, and the opening and closing of the anti-drop grid can control whether the cooling water in the reactor cavity flows into the water injection flow channel. The driving component is connected to the anti-drop grid, and is used to drive the anti-drop grid to open or close. The detection control component is electrically connected to the driving component, and is used to detect whether there is cooling water on the top surface of the annular main shielding wall, and control the action of the driving component according to the detection result, so that the anti-drop grid is opened or closed.

[0007] In some embodiments, the top surface of the anti-drop grille is flush with the top surface of the annular main shielding wall, and a water diversion groove is provided on the top surface of the annular main shielding wall, and the water diversion groove is close to the anti-drop grille. The detection control component includes a buoyancy member and a position detection switch. The buoyancy member is disposed in the water diversion groove and can follow the rise and fall of the water level in the water diversion groove. The position detection switch is disposed in the water diversion groove and is electrically connected to the driving component, and is used to detect whether there is cooling water on the top surface of the annular main shielding wall according to the position change of the buoyancy member, and control the action of the driving component according to the detection result.

[0008] In some embodiments, the anti-drop grille is hinged at the upper opening of the water injection channel. The anti-drop grille assembly further includes a support spring, one end of which abuts against the bottom of the anti-drop grille and the other end abuts against the inner wall of the water injection channel, and is used to keep the anti-drop grille closed when there is no cooling water above the anti-drop grille. When the water level of the cooling water on the anti-drop grille reaches a preset water level, the gravity of the cooling water compresses the support spring, thereby opening the closed anti-drop grille.

[0009] In some embodiments, a wind shield is provided at the lower opening of the water injection channel, and the wind shield is hinged to the inner wall of the reactor pit.

[0010] In some embodiments, the windshield is made of an alloy including stainless steel or lead.

[0011] In some embodiments, the water injection channel is L-shaped.

[0012] In some embodiments, the water injection channel includes a vertical section and an inclined section that are interconnected; the vertical section is located above the inclined section, the upper end of the vertical section is connected to the reactor cavity, and the bottom end of the inclined section is connected to the reactor pit.

[0013] In some embodiments, the bottom end of the water injection channel is located at the bottom of the reactor pit.

[0014] Therefore, the reactor cavity water injection channel structure in the embodiment of the present invention can connect the reactor cavity and the reactor pit by opening a water injection channel inside the annular main shielding wall. In the event of a safety accident such as an accidental loss of water, the cooling water in the reactor cavity can flow into the reactor pit to cool the pressure vessel in the reactor pit and improve the safety of the pressure vessel. Compared with the process pipelines arranged in the internal space of the reactor building in the prior art, the water injection channel is directly formed in the annular main shielding wall, which reduces the design difficulty of the water injection channel and makes the water injection channel not occupy the internal space in the reactor building; the water injection channel requires less maintenance and does not involve the replacement of wearing parts such as valves, so the reliability of the water injection channel is high and maintenance-free can be achieved to a certain extent, thereby reducing the maintenance workload of the staff and reducing the labor intensity of the staff. Furthermore, by setting an anti-drop grille, a driving component and a detection control component, and making the detection control component detect whether there is cooling water on the top surface of the annular main shielding wall, the driving component is controlled to operate according to the detection result to open or close the anti-drop grille. Therefore, the anti-drop grille can be automatically opened and closed according to whether there is cooling water on the top surface of the annular main shielding wall, thereby further reducing the labor intensity of the staff when operating the anti-drop grille; and the anti-drop grille can be opened in a linked manner when the cooling water is just started to be injected into the reactor cavity, thereby improving the timeliness of the opening of the anti-drop grille.

[0015] In a second aspect, an embodiment of the present invention further provides a reactor building, which includes a containment, the reactor cavity water injection channel structure in the first aspect, a pressure vessel, and a reactor cavity water injection system. The reactor cavity water injection channel structure is located in the containment. The pressure vessel is arranged in the reactor pit. The reactor cavity water injection system is arranged above the annular main shielding wall in the containment, and is used to inject cooling water into the reactor cavity in the event of a safety accident. The cooling water in the reactor cavity flows into the reactor pit through the water injection channel to cool the pressure vessel.

[0016] In some embodiments, there are multiple reactor cavity water injection channel structures, and the multiple reactor cavity water injection channel structures are arranged around the axis of the pressure vessel.

[0017] The reactor building provided by the embodiment of the present invention has the same beneficial effects as the above-mentioned reactor cavity water injection channel structure, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 : A structural diagram of a reactor cavity water injection flow channel structure provided by an embodiment of the present invention;

[0019] Figure 2 : A cross-sectional view of a reactor building provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0021] Embodiment 1:

[0022] like Figure 1 As shown, an embodiment of the present invention provides a reactor cavity water injection flow channel structure, which is applied in a reactor building to inject cooling water in the reactor cavity into the reactor pit to cool the pressure vessel.

[0023] Combination Figure 1 and Figure 2 The reactor cavity water injection channel structure includes an annular main shielding wall 1, a water injection channel 2 and an anti-drop grid assembly. The annular main shielding wall 1 is located between the reactor cavity and the reactor pit in the containment. The water injection channel 2 is opened inside the annular main shielding wall 1 and is used to connect the reactor cavity and the reactor pit so that the cooling water flowing into the reactor cavity can flow into the reactor pit through the water injection channel 2.

[0024] like Figure 1 As shown, the area enclosed by the annular main shielding wall 1 forms a reactor pit, and a part of the pressure vessel is arranged in the reactor pit. The space above the annular main shielding wall 1 forms a reactor cavity.

[0025] For example, the number of the water injection channels 2 may be one or more. The water injection channels 2 may be formed by the concrete structure of the annular main shielding wall 1, or by pre-buried pipes in the annular main shielding wall 1.

[0026] In the event of a safety accident (such as an accidental loss of water), the cooling water of the safety system in the reactor is discharged into the reactor cavity and flows into the reactor pit through the water injection channel 2 to cool the pressure vessel in the reactor pit, thereby improving the safety of the pressure vessel. In addition, compared with the process pipelines arranged in the internal space of the reactor building in the prior art, the water injection channel 2 is directly formed in the annular main shielding wall 1, which reduces the design difficulty of the water injection channel 2 and makes the water injection channel 2 not occupy the internal space in the reactor building; the water injection channel 2 requires less maintenance and does not involve the replacement of wearing parts such as valves, so the reliability of the water injection channel 2 is high, and maintenance-free can be achieved to a certain extent, thereby reducing the maintenance workload of the staff and reducing the labor intensity of the staff.

[0027] like Figure 1As shown, the anti-drop grille assembly includes an anti-drop grille 3, a driving component and a detection control component. The anti-drop grille 3 is arranged at the upper end opening of the water injection channel 2. The opening and closing of the anti-drop grille 3 can control whether the cooling water in the reactor cavity flows into the water injection channel 2. The driving component is connected to the anti-drop grille 3 and is used to drive the anti-drop grille 3 to open or close. The detection control component is electrically connected to the driving component and is used to detect whether there is cooling water on the top surface of the annular main shielding wall 1, and control the action of the driving component according to the detection result to open or close the anti-drop grille 3.

[0028] Exemplarily, the material of the anti-drop grid 3 is a metal material capable of shielding radiation, such as stainless steel or lead, so as to prevent the radiation in the reactor pit from leaking into the reactor cavity along the water injection channel 2 and the anti-drop grid 3.

[0029] Exemplarily, the anti-drop grille 3 can be opened and closed by translation or flipping.

[0030] When the anti-drop grille 3 is closed, the anti-drop grille 3 separates the reactor cavity and the water injection channel 2 from each other, and the cooling water in the reactor cavity cannot enter the water injection channel 2; at this time, the anti-drop grille 3 does not occupy the internal space in the reactor cavity, and can prevent people and foreign objects from falling into the water injection channel 2.

[0031] When the anti-drop grid 3 is opened, the reactor cavity and the water injection channel 2 are interconnected, and the cooling water in the reactor cavity can enter the water injection channel 2 and flow into the reactor pit.

[0032] Exemplarily, the driving component may be driven by electricity, and the driving component may be arranged in a variety of ways.

[0033] For example, the driving component may be disposed above the anti-drop grille 3 , and when the anti-drop grille 3 needs to be opened or closed, the driving component may lift or put back the anti-drop grille 3 .

[0034] Alternatively, the driving component is disposed below the anti-drop grille 3, and when the anti-drop grille 3 needs to be opened or closed, the driving component can flip the anti-drop grille 3 to a vertical direction or a horizontal direction.

[0035] Exemplarily, the detection control component includes a water level detector and a programmable controller.

[0036] Exemplarily, after the cooling water of the safety system in the reactor flows into the reactor cavity, it first floods the top surface of the main shielding wall 1. After detecting the cooling water, the detection and control component sends a first control signal to the driving component to control the driving component to open the anti-drop grille 3, so that the cooling water in the reactor cavity flows into the reactor pit; after all the cooling water in the reactor cavity flows out, there is no cooling water on the top surface of the main shielding wall 1, and the detection and control component sends a second control signal to the driving component to control the driving component to close the anti-drop grille 3, thereby preventing people or foreign objects from falling into the water injection channel 2.

[0037] Through the above-mentioned arrangement, the anti-drop grille 3 can be automatically opened and closed according to whether there is cooling water on the top surface of the annular main shielding wall 1, further reducing the labor intensity of the staff when operating the anti-drop grille 3; and the anti-drop grille 3 can be opened in a linked manner when the cooling water is just started to be injected into the reactor cavity, thereby improving the timeliness of the opening of the anti-drop grille 3.

[0038] Therefore, the reactor cavity water injection channel structure in the embodiment of the present invention can connect the reactor cavity and the reactor pit by opening the water injection channel 2 inside the annular main shielding wall 1. In the event of a safety accident (such as an accidental water loss accident), the cooling water in the reactor cavity can flow into the reactor pit to cool the pressure vessel in the reactor pit and improve the safety of the pressure vessel. Compared with the process pipelines arranged in the internal space of the reactor building in the prior art, the water injection channel 2 is directly formed in the annular main shielding wall 1, which reduces the design difficulty of the water injection channel 2 and makes the water injection channel 2 not occupy the internal space in the reactor building; the water injection channel 2 needs less maintenance and does not involve the replacement of wearing parts such as valves, so the reliability of the water injection channel 2 is high and maintenance-free can be achieved to a certain extent, thereby reducing the maintenance workload of the staff and reducing the labor intensity of the staff. Furthermore, by providing an anti-drop grille 3, a driving component and a detection control component, and enabling the detection control component to detect whether there is cooling water on the top surface of the annular main shielding wall 1, the driving component is controlled to operate according to the detection result to open or close the anti-drop grille 3. Therefore, the anti-drop grille 3 can be automatically opened and closed according to whether there is cooling water on the top surface of the annular main shielding wall 1, thereby further reducing the labor intensity of the staff when operating the anti-drop grille 3; and the anti-drop grille 3 can be opened in a linked manner when the cooling water is just started to be injected into the reactor cavity, thereby improving the timeliness of the opening of the anti-drop grille 3.

[0039] In some embodiments, Figure 1As shown, the top surface of the anti-drop grille 3 is flush with the top surface of the annular main shielding wall 1, and a water diversion groove 5 is provided on the top surface of the annular main shielding wall 1, and the water diversion groove 5 is close to the anti-drop grille 3. The detection control component includes a buoyancy member and a position detection switch. The buoyancy member is arranged in the water diversion groove 5, and can follow the rise and fall of the water level in the water diversion groove 5. The position detection switch is arranged in the water diversion groove 5 and is electrically connected to the driving component, and is used to detect whether there is cooling water on the top surface of the annular main shielding wall 1 according to the position change of the buoyancy member, and control the action of the driving component according to the detection result.

[0040] By making the top surface of the anti-drop grille 3 flush with the top surface of the annular main shielding wall 1, the space occupied by the anti-drop grille 3 on the top surface of the annular main shielding wall 1 can be reduced, and the flatness of the top surface of the annular main shielding wall 1 can be maintained, avoiding affecting the equipment and personnel movement on the top surface of the annular main shielding wall 1.

[0041] Exemplarily, the water channel 5 is arranged about 0.5m away from the anti-drop grid 3, and the water channel 5 is 0.5m deep. The buoyancy member may be a floating ball, a magnet is arranged inside the floating ball, and the position detection switch detects the position change of the floating ball by detecting the change of the magnetic field.

[0042] Under normal working conditions (the safety system does not release cooling water into the reactor cavity), the buoyancy member is placed at the bottom of the water diversion groove 5 by gravity, and the anti-drop grille 3 is in a closed state. Under accident working conditions (the safety system releases cooling water into the reactor cavity), the cooling water floods the water diversion groove 5, and the buoyancy member floats to the upper part of the water diversion groove 5 under the action of buoyancy. The floating of the buoyancy member drives the internal magnet to move, and the position detection switch outputs a control signal according to the position change of the magnet in the buoyancy member, and the control signal controls the action of the driving component to open the anti-drop grille 3.

[0043] Through the above arrangement, the opening and closing of the anti-drop grille 3 can be controlled by the buoyancy member and the position detection switch, and the buoyancy member and the position detection switch have simple structures and thus have high accuracy and reliability.

[0044] In some embodiments, Figure 1 As shown, the anti-drop grille 3 is hinged at the upper opening of the water injection channel 2. The anti-drop grille assembly also includes a support spring, one end of which abuts against the bottom of the anti-drop grille 3 and the other end abuts against the inner wall of the water injection channel 2, and is used to keep the anti-drop grille 3 closed when there is no cooling water above the anti-drop grille 3. When the water level of the cooling water on the anti-drop grille 3 reaches a preset water level, the gravity of the cooling water compresses the support spring, thereby opening the closed anti-drop grille 3.

[0045] Exemplarily, the support spring is a compression spring. The parameters of the support spring (initial length, elastic force, deformation, etc.) can be set according to the above-mentioned preset water level, the size of the anti-drop grid 3, and other factors.

[0046] Under normal working conditions, the elastic force of the support spring is sufficient to support the anti-drop grille 3, so that the anti-drop grille 3 is in a closed state. Under accident conditions, after the cooling water flows onto the anti-drop grille 3, the downward pressure of the anti-drop grille 3 is increased, and the support spring is compressed, so that the closed anti-drop grille 3 is opened.

[0047] Through the above-mentioned setting, the anti-drop grille 3 can be automatically opened when the cooling water reaches the preset water level, thereby realizing the passive control of the anti-drop grille 3. The anti-drop grille 3 can still be automatically opened when the control component or the driving component fails, thereby improving the reliability of the anti-drop grille assembly.

[0048] In some examples, the number and aperture of the water injection channels 2 are determined based on the ventilation conditions of the reactor pit to meet the flow rate requirements for water injection into the reactor pit under accident conditions, while taking into account the effect of the water injection channels 2 on the ventilation escape of the reactor pit.

[0049] For example, the ventilation air volume of the reactor pit is 16700m 3 / h, the number of water injection channels 2 can be set to four, and the aperture of the water injection channel 2 can be set to 350 mm; or, the aperture of the water injection channel 2 can be set to 400 mm, but in this case, a wind shield 4 needs to be added to the water injection channel 2.

[0050] For example, the ventilation air volume of the reactor pit is 15250m 3 / h, the number of water injection channels 2 can be set to eight, and the aperture of the water injection channel 2 can be set to 450 mm; or, the aperture of the water injection channel 2 can be set to 500 mm, but in this case, it is also necessary to add a wind shield 4 in the water injection channel 2.

[0051] In some embodiments, Figure 1 As shown, a wind shield 4 is provided at the lower opening of the water injection channel 2, and the wind shield 4 is hinged on the inner wall of the reactor pit.

[0052] In some examples, the wind shield 4 can shield radiation. The material of the wind shield 4 is an alloy containing stainless steel or lead to prevent the radiation in the reactor pit from leaking into the reactor cavity along the water injection channel 2.

[0053] For example, when cooling water flows in the water injection channel 2, the impact force generated by the cooling water and its own gravity will cause the wind shield 4 to open, so that the cooling water can enter the reactor pit; when there is no cooling water in the water injection channel 2, or the flow rate of the cooling water is close to 0, the wind shield 4 will be closed due to its own gravity.

[0054] Through the above arrangement, the wind shield 4 can be automatically opened and closed, so that the cooling water in the water injection channel 2 can flow into the reactor pit, and the escape of ventilation air volume in the reactor pit can be reduced.

[0055] It should be noted that the shape of the water injection channel 2 can be adaptively selected according to the specific layout of the reactor type to ensure effective injection of cooling water. For example, the shape of the water injection channel 2 can be determined based on whether there are other system buried pipes and structural spaces in the annular main shielding wall 1 to avoid mutual interference.

[0056] In some embodiments, Figure 1 As shown, the shape of the water injection channel 2 is L-shaped.

[0057] In this case, the cooling water entering the water injection channel 2 first falls vertically and then is horizontally injected into the reactor pit, so that the cooling water in the reactor cavity can quickly enter the water injection channel 2.

[0058] In other examples, such as Figure 1 As shown, the water injection channel 2 includes a vertical section and an inclined section which are interconnected; the vertical section is located above the inclined section, the upper end of the vertical section is connected to the reactor cavity, and the bottom end of the inclined section is connected to the reactor pit.

[0059] In this case, the cooling water entering the water injection channel 2 is first injected vertically and then injected obliquely, which is beneficial to reducing the total resistance of the cooling water when flowing in the water injection channel 2.

[0060] In some embodiments, Figure 1 As shown, the bottom end of the water injection channel 2 is located at the bottom of the reactor pit.

[0061] This allows cooling water to be directly input into the bottom of the reactor pit to quickly cool the bottom of the pressure vessel in the reactor pit.

[0062] Embodiment 2:

[0063] like Figure 2 As shown, an embodiment of the present invention further provides a reactor building, which is applied to a nuclear power plant. The reactor building includes a containment, the reactor cavity water injection channel structure in Embodiment 1, a pressure vessel, and a reactor cavity water injection system. The reactor cavity water injection channel structure is located in the containment. The pressure vessel is arranged in the reactor pit. The reactor cavity water injection system is arranged above the annular main shielding wall 1 in the containment, and is used to inject cooling water into the reactor cavity in the event of a safety accident. The cooling water in the reactor cavity flows into the reactor pit through the water injection channel 2 to cool the pressure vessel.

[0064] Exemplarily, the reactor cavity water injection system includes an injection tank, which is used to store cooling water and is provided with a valve.

[0065] In the event of a safety accident, the valve on the injection tank is opened, and the cooling water in the injection tank is injected into the reactor cavity and flows into the reactor pit through the injection channel 2 to cool the pressure vessel.

[0066] Through the above arrangement, in the event of a safety accident, the cooling water in the reactor cavity water injection system can smoothly enter the reactor pit to cool the pressure vessel, thereby improving the safety of the reactor building. In addition, by providing the water injection channel 2, the difficulty of designing and maintaining the reactor building can be reduced, thereby reducing the labor intensity of the staff.

[0067] In some embodiments, in combination Figure 1 and Figure 2 There are multiple reactor cavity water injection channel structures, and the multiple reactor cavity water injection channel structures are arranged around the axis of the pressure vessel.

[0068] Through the above-mentioned arrangement, the cooling water in the reactor cavity can enter the multiple water injection channels 2 from multiple positions, which can avoid the uneven water volume at each position in the reactor cavity affecting the speed of flowing into the water injection channels 2. Therefore, the amount of water injected from the reactor cavity into the reactor pit can be increased, so that the cooling water can quickly enter the reactor pit to cool the pressure vessel, thereby improving the safety of the reactor building.

[0069] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A reactor cavity water injection channel structure, characterized in that: include: An annular main shielding wall (1) is located between the reactor cavity and the reactor pit in the containment vessel; A water injection channel (2) is provided inside the annular main shielding wall (1) and is used to connect the reactor cavity and the reactor pit, so that cooling water flowing into the reactor cavity can flow into the reactor pit through the water injection channel (2); and, An anti-drop grille assembly, comprising an anti-drop grille (3), a driving component and a detection and control component; The anti-drop grid (3) is arranged at the upper opening of the water injection channel (2), and the opening and closing of the anti-drop grid (3) can control whether the cooling water in the reactor cavity flows into the water injection channel (2); The driving component is connected to the anti-drop grille (3) and is used to drive the anti-drop grille (3) to open or close; The detection control component is electrically connected to the driving component and is used to detect whether there is cooling water on the top surface of the annular main shielding wall (1), and control the operation of the driving component according to the detection result to open or close the anti-drop grille (3).

2. The reactor cavity water injection channel structure according to claim 1, characterized in that: The top surface of the anti-drop grille (3) is flush with the top surface of the annular main shielding wall (1), and a water diversion groove (5) is provided on the top surface of the annular main shielding wall (1), and the water diversion groove (5) is close to the anti-drop grille (3); The detection control component comprises: A buoyancy member, arranged in the water diversion channel (5), capable of following the rise and fall of the water level in the water diversion channel (5); and, A position detection switch is arranged in the water diversion groove (5) and is electrically connected to the driving component, and is used to detect whether there is cooling water on the top surface of the annular main shielding wall (1) according to the position change of the buoyancy member, and control the operation of the driving component according to the detection result.

3. The reactor cavity water injection channel structure according to claim 1 or 2, characterized in that: The anti-falling grille (3) is hinged at the upper opening of the water injection channel (2); The anti-drop grille assembly further comprises a support spring, one end of which abuts against the bottom of the anti-drop grille (3), and the other end of which abuts against the inner wall of the water injection channel (2), and is used to keep the anti-drop grille (3) in a closed state when there is no cooling water above the anti-drop grille (3); When the water level of the cooling water on the anti-drop grille (3) reaches a preset water level, the gravity of the cooling water compresses the support spring, thereby opening the closed anti-drop grille (3).

4. The reactor cavity water injection channel structure according to claim 3, characterized in that: A windshield (4) is provided at the lower opening of the water injection channel (2), and the windshield (4) is hinged on the inner wall of the reactor pit.

5. The reactor cavity water injection channel structure according to claim 4, characterized in that: The material of the windshield (4) is an alloy containing stainless steel or lead.

6. The reactor cavity water injection channel structure according to claim 3, characterized in that: The water injection channel (2) is in an L-shape.

7. The reactor cavity water injection channel structure according to claim 3, characterized in that: The water injection channel (2) comprises a vertical section and an inclined section which are connected to each other; the vertical section is located above the inclined section, the upper end of the vertical section is connected to the reactor cavity, and the bottom end of the inclined section is connected to the reactor pit.

8. The reactor cavity water injection channel structure according to claim 3, characterized in that: The bottom end of the water injection channel (2) is located at the bottom of the reactor pit.

9. A reactor building, characterized in that: include: Containment; The reactor cavity water injection channel structure according to any one of claims 1 to 8, located in the containment vessel; A pressure vessel, which is installed in the reactor pit; and, A reactor cavity water injection system, arranged above the annular main shielding wall (1) in the containment vessel, for injecting cooling water into the reactor cavity in the event of a safety accident; The cooling water in the reactor cavity flows into the reactor pit through the water injection channel (2) to cool the pressure vessel.

10. The reactor building according to claim 9, characterized in that: There are multiple reactor cavity water injection channel structures, and the multiple reactor cavity water injection channel structures are arranged around the axis of the pressure vessel.

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