lead bismuth pile

Abstract

This invention relates to the field of nuclear reactor reactivity control technology, specifically to a lead-bismuth reactor, comprising: a reactor core, safety rods, a reactor vessel, and a coolant. The reactor core is disposed within the reactor vessel, the safety rods are configured to be inserted into the reactor core for reactor shutdown, and the coolant is disposed within the reactor vessel to cool the reactor core. A space is formed within the reactor vessel to prevent the safety rods from contacting the coolant during insertion into the reactor core. In this embodiment of the lead-bismuth reactor, the safety rods are configured to fall under their own weight and insert into the reactor core for reactor shutdown, and the safety rods are physically isolated from the coolant. This prevents the safety rods from being affected by the buoyancy of the coolant during their fall, thus ensuring rapid insertion into the reactor core. In accident conditions, the lead-bismuth reactor can achieve passive and rapid shutdown under gravity, improving the safety and reliability of the lead-bismuth reactor.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of reactivity control technology for nuclear reactors, and specifically to a lead-bismuth reactor. Background Technology

[0002] The statements herein are provided merely as background information relating to the invention and do not necessarily constitute prior art. Nuclear reactors need to have the ability to shut down rapidly in the event of an accident. Safety rods and their driving devices are devices installed in the reactor that can quickly shut down the reactor by driving the safety rods to drop. They are key equipment for ensuring the safety and reliability of the reactor. Summary of the Invention

[0003] A brief overview of this application is provided below to offer a basic understanding of certain aspects thereof. It should be understood that this overview is not an exhaustive summary of the application. It is not intended to identify key or essential parts of the application, nor is it intended to limit its scope. Its purpose is merely to present certain concepts in a simplified form as a prelude to the more detailed description that follows.

[0004] An embodiment of the present invention provides a lead-bismuth reactor, comprising: a reactor core, a safety rod, a reactor vessel, and a coolant. The reactor core is disposed within the reactor vessel, the safety rod is configured to be inserted into the reactor core for reactor shutdown, and the coolant is disposed within the reactor vessel to cool the reactor core. A space is formed within the reactor vessel to prevent the safety rod from contacting the coolant during insertion into the reactor core.

[0005] In the embodiments of the present invention, the lead-bismuth reactor is configured to use a safety rod that can fall under its own weight and insert into the reactor core to shut down the reactor. By creating a space within the reactor container, the safety rod is physically isolated from the coolant, preventing the safety rod from being affected by the buoyancy of the coolant during its fall and thus avoiding its inability to quickly insert into the reactor core. This allows the lead-bismuth reactor to achieve passive and rapid shutdown under gravity in the event of an accident, thereby improving the safety and reliability of the lead-bismuth reactor. Attached Figure Description

[0006] Other objects and advantages of the invention will become apparent from the following description of embodiments of the invention with reference to the accompanying drawings, and will help to provide a comprehensive understanding of the invention.

[0007] Figure 1 This is a schematic diagram of a lead-bismuth stack according to an embodiment of the present invention.

[0008] Explanation of reference numerals in the attached figures:

[0009] 10. Core; 20. Safety bar; 30. Container; 40. Coolant; 50. Upper grid plate; 60. Lower grid plate; 70. Safety bar sleeve; 71. Connector; 80. Mounting component; 90. Cover; 100. Drive assembly; 101. Drive unit; 110. Power component; 120. Clamping component; 130. Seal.

[0010] It should be noted that the accompanying drawings are not necessarily drawn to scale, but are shown only in a schematic manner without affecting the reader's understanding. Detailed Implementation

[0011] Exemplary embodiments of the invention will be described below with reference to the accompanying drawings. For clarity and brevity, not all features of actual implementations are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the development of any such actual embodiment to achieve the developer's specific goals, such as complying with constraints related to the system and business, and these constraints may vary depending on the implementation. Furthermore, it should be understood that while development work can be very complex and time-consuming, such development work is merely a routine task for those skilled in the art who benefit from the content of this application.

[0012] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the device structure and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0013] The inventors of this invention discovered that during an emergency shutdown of a lead-bismuth reactor in the event of an accident, the safety rods, when lowered into the reactor core, are subject to strong buoyancy from the coolant, preventing them from falling quickly. Currently, auxiliary rod-dropping devices are typically used to add extra weight to the safety rods, combined with springs and other components for assisted dropping. However, these components are prone to wear and tear after prolonged use, leading to malfunctions and potentially causing the lead-bismuth reactor shutdown system to fail. Furthermore, these auxiliary rod-dropping devices occupy additional space, hindering the miniaturization of lead-bismuth reactors.

[0014] Based on this, embodiments of the present invention provide a lead-bismuth stack, such as... Figure 1 The diagram shows a schematic representation of the lead-bismuth reactor structure, which includes: a reactor core 10, a safety rod 20, a reactor vessel 30, and a coolant 40. The reactor core 10 is disposed within the reactor vessel 30. The safety rod 20 is configured to be inserted into the reactor core 10 to shut down the reactor. The coolant 40 is disposed within the reactor vessel 30 to cool the reactor core 10. A space is formed within the reactor vessel 30 to prevent the safety rod 20 from contacting the coolant 40 during insertion into the reactor core 10.

[0015] In the lead-bismuth reactor embodiment of the present invention, the safety rod 20 is configured to fall under its own weight and insert into the reactor core 10 to shut down the reactor. By forming a space within the reactor container 30, the safety rod 20 is physically isolated from the coolant 40, preventing the safety rod 20 from being affected by the buoyancy of the coolant 40 during its fall and thus preventing it from quickly inserting into the reactor core 10. This allows the lead-bismuth reactor to achieve passive and rapid shutdown under gravity in the event of an accident, improving the safety and reliability of the lead-bismuth reactor.

[0016] In this embodiment, the stack container 30 is configured to contain the coolant 40 and form the primary loop safety boundary of the lead-bismuth stack to contain radioactive materials and prevent radioactive leakage.

[0017] In some embodiments, the safety rod 20 may be a single rod or a bundle of rods consisting of multiple single rods, and the material constituting the safety rod 20 may be a neutron absorbing material, such as boron carbide.

[0018] In some embodiments, the lead-bismuth reactor may further include an upper grid plate 50, a lower grid plate 60, and a safety rod sleeve 70. The reactor core 10 is fixed between the upper grid plate 50 and the lower grid plate 60. The cavity of the safety rod sleeve 70 forms a space. One end of the safety rod sleeve 70 is fixed to the lower grid plate 60, and the other end of the safety rod sleeve 70 extends to the coolant level above the upper grid plate 50. The safety rod sleeve 70 is inserted into the interior of the reactor core 10 to isolate the coolant 40 and prevent the coolant 40 from entering the interior of the safety rod sleeve 70. Since there is no coolant inside the safety rod sleeve 70, the safety rod 20 is inserted into the safety rod sleeve 70 so that the safety rod 20 is not affected by the buoyancy of the coolant 40 when falling and quickly inserts into the reactor core 10, ensuring the safety of the lead-bismuth reactor.

[0019] In this embodiment, the upper grid plate 50 provides a clamping force to the core 10, and the lower grid plate 60 is used to support the core 10 so as to limit the core 10 under the combined action of the upper grid plate 50 and the lower grid plate 60. Furthermore, the upper grid plate 50 and the lower grid plate 60 are used to provide flow channels for the coolant 40, which flows in through the lower grid plate 60 and flows out through the upper grid plate 50.

[0020] In some embodiments, the safety rod sleeve 70 is configured with the same structure as the fuel assembly sleeve of the reactor core 10, so that the safety rod sleeve 70 can be inserted into the interior of the reactor core 10 in a manner similar to that of a fuel assembly. That is, the safety rod sleeve 70 can be fixed in a manner similar to that of a fuel assembly, thereby avoiding the need for redesign of the reactor core structure.

[0021] In some embodiments, a predetermined gap is maintained between the safety rod 20 and the safety rod sleeve 70 when the safety rod 20 falls into the safety rod sleeve 70. Since the safety rod sleeve 70 is easily deformed due to excessively high temperatures inside the reactor core 10, this embodiment is configured such that a predetermined gap is maintained between the safety rod 20 and the safety rod sleeve 70 when the safety rod 20 falls into the safety rod sleeve 70. This is to prevent deformation of the safety rod sleeve 70 from affecting the falling of the safety rod and thus hindering timely reactor shutdown. For example, the inner diameter of the safety rod sleeve 70 can be slightly larger than the outer diameter of the safety rod 20.

[0022] In some embodiments, the upper part of the safety rod sleeve 70 is open and communicates with the air in the in-core gas cavity, while the bottom of the safety rod sleeve 70 is closed to prevent the coolant 40 from entering the interior of the safety rod sleeve 70, thereby physically isolating the safety rod sleeve 70 from the coolant 40.

[0023] In this embodiment, the safety rod sleeve 70 can be configured as a cylindrical container with an opening at the top and a sealed bottom. The cylindrical container is configured to extend above the coolant 40 level to physically isolate the safety rod sleeve 70 from the coolant 40. For example, the cylindrical container can be cylindrical or hexagonal like the fuel assembly sleeve of the reactor core 10.

[0024] Furthermore, the bottom of the safety rod sleeve 70 can be fixedly connected to the lower grid plate 60 to prevent the safety rod sleeve 70 from being floated by the buoyancy of the coolant 40, which would prevent the safety rod 20 from being inserted into the core 10 under accident conditions, thus preventing timely shutdown of the reactor.

[0025] Specifically, in some embodiments, the safety stick sleeve 70 includes a connector 71 connected to the bottom of the safety stick sleeve 70, thereby fixing the safety stick sleeve 70 to the lower grid plate 60. For example, the safety stick sleeve 70 may be welded to or snap-fitted to the lower grid plate 60.

[0026] In some embodiments, the safety rod sleeve 70 may be made of corrosion-resistant steel to improve its durability and reliability, thereby ensuring the safety of the lead-bismuth pile. At the same time, it reduces the replacement frequency of the safety rod sleeve 70 and saves costs.

[0027] Furthermore, the safety rod sleeve 70 can be configured to have a certain thickness. Specifically, the thickness can be set to ensure that it has sufficient mechanical strength when used in high temperature, strong radioactivity and strong corrosive environment, while ensuring that it will not have a significant impact on the reactivity value of the safety rod.

[0028] In some embodiments, the fuel assemblies, upper grid plate 50, lower grid plate 60, and safety rod sleeve 70 of the core 10 are configured as an integral module to facilitate installation and disassembly, while also allowing for flexible layout within the lead-bismuth stack, thereby improving the utilization efficiency of space within the lead-bismuth stack.

[0029] In some embodiments, the lead-bismuth reactor may further include a mounting member 80. The mounting member 80 is configured to assemble the fuel assemblies, upper grid plate 50, lower grid plate 60, and safety rod sleeve 70 of the reactor core 10 into an integral module. Specifically, when installing the devices and components within the lead-bismuth reactor, the fuel assemblies, upper grid plate 50, lower grid plate 60, and safety rod sleeve 70 of the reactor core 10 can be installed into the mounting member 80 in a predetermined order to form an integral module, which is then installed in the reactor container 30 as an integral module. For example, the mounting member 80 may be a basket, etc.

[0030] In some embodiments, the lead-bismuth stack may further include a cover 90. The cover 90 is disposed on top of the stack container 30 and connected to the stack container 30. The cover 90 is used to seal the stack container 30 to prevent radioactive leakage and ensure the airtightness of the stack container 30.

[0031] In some embodiments, the lead-bismuth stack may further include a drive assembly 100 and a power component 110, which are disposed above the stack container 30. The drive assembly 100 clamps a safety rod 20, and the power component 110 is connected to the drive assembly 100. The power component 110 drives the drive assembly 100 to move along the extension direction of the safety rod 20. The drive assembly 100 moves the safety rod 20 along its extension direction to insert it into the stack core 10 or to rise away from the stack core 10. In an accident, the drive assembly 100 loses its clamping effect on the safety rod 20, and the safety rod 20 falls freely. For example, the power component 110 may be a motor to provide power to the drive assembly 100. The drive assembly 100 and the power component 110 operate the safety rod 20 under normal operating conditions to insert it into or remove it from the stack core. In some embodiments, the drive assembly may include a gripper that clamps the safety rod. In an accident, the gripper loses its clamping effect on the safety rod, allowing the safety rod to fall freely.

[0032] In some embodiments, the drive assembly 100 may include a gear, a rack, and a drive unit 101. The gear and rack are meshed together, the rack is connected to one end of the drive unit 101, and the other end of the drive unit 101 passes through the cover 90 and extends into the interior of the stacking container 30. The rotation of the gear in the drive assembly 100 drives the rack to move up and down, thereby driving the drive unit 101 to move up and down.

[0033] In some embodiments, the lead-bismuth stack may further include a clamping member 120, which is configured such that one end is connected to the drive unit 101 and the other end is capable of clamping the safety rod 20. During normal operation of the lead-bismuth stack, the gears and racks in the drive assembly 100 drive the drive unit 101 to move upward, thereby driving the clamping member 120 to move upward and lift the safety rod 20 above the core 10. In the event of an accident, the clamping member 120 releases the safety rod 20, allowing the safety rod 20 to fall into the core 10 under its own gravity, thereby achieving rapid shutdown.

[0034] In some embodiments, the drive unit 101 may be configured as a rod.

[0035] In this embodiment, when the lead-bismuth reactor is running normally, the safety rod 20 is raised above the reactor core 10 by the drive assembly 100 and the clamping member 120. The safety rod 20 is not affected by the high temperature of the reactor core 10, and there is less residual heat after the reactor is quickly shut down in an accident. Therefore, there is no need to set up a separate cooling system for the safety rod 20 to cool it, which can meet the thermal design requirements of the lead-bismuth reactor.

[0036] In some embodiments, the lead-bismuth stack may further include a seal 130 disposed within the cover 90, matching the shape and size of the drive unit 101, the drive unit 101 being sealed through the seal 130. The seal 130 is used to ensure the airtightness of the stack container 30 and prevent radioactive leakage.

[0037] In some embodiments, the lead-bismuth reactor may further include an auxiliary rod dropping device, which serves as an auxiliary device for driving the safety rod 20 to fall rapidly into the reactor core 10. The auxiliary rod dropping device contains an energy storage mechanism such as a spring. In the event that the safety rod sleeve 70 is damaged or cannot be fixedly connected to the lower grid plate 60, thereby preventing the safety rod 20 from falling rapidly into the reactor core 10, the safety rod 20 can fall under the action of the auxiliary rod dropping device, thereby stopping the reactor and further ensuring the safety of the lead-bismuth reactor.

[0038] In some embodiments, the lead-bismuth stack may further include a buffer device, which is used to prevent the safety rod 20 from rebounding due to impact force when it falls into the core 10, so as to ensure that the safety rod 20 can fall quickly to the predetermined position, thereby achieving rapid shutdown of the stack.

[0039] Regarding the embodiments of the present invention, it should also be noted that, without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to obtain new embodiments.

[0040] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A lead bismuth stack, characterized in that, It includes: Core, safety bars, reactor container, coolant The reactor core is disposed within the reactor container. The safety bar is configured to be inserted into the reactor core to stop the reactor; The coolant is disposed inside the reactor vessel to cool the reactor core. A space is formed within the reactor container to ensure that the safety bar does not come into contact with the coolant during insertion into the reactor core. It also includes a safety bar sleeve, the cavity of which forms the space. The bottom of the safety rod sleeve is closed, and the other end of the safety rod sleeve extends above the coolant liquid level. The safety rod sleeve is inserted into the interior of the reactor core.

2. The lead bismuth eutectic stack of claim 1, wherein, It also includes an upper grid plate and a lower grid plate. The core is fixed between the upper grid plate and the lower grid plate. The bottom of the safety rod sleeve is fixed to the lower grid plate, and the other end of the safety rod sleeve extends to the coolant level above the upper grid plate.

3. The lead bismuth eutectic stack of claim 1, wherein, The safety rod sleeve is configured with the same structure as the fuel assembly sleeve of the reactor core.

4. The lead-bismuth pile according to claim 1, characterized in that, When the safety bar falls into the safety bar sleeve, a predetermined gap is left between the safety bar and the safety bar sleeve.

5. The lead-bismuth pile according to claim 1, characterized in that, The upper opening of the safety rod sleeve is connected to the air in the in-pile air chamber.

6. The lead-bismuth pile according to claim 2, characterized in that, The fuel assemblies, upper grid plate, lower grid plate, and safety rod sleeve of the reactor core are configured as an integral module.

7. The lead-bismuth pile according to any one of claims 1-6, characterized in that, It also includes a buffer device, which is located at the bottom of the safety bar sleeve. When the safety bar falls into the safety bar sleeve, the safety bar interacts with the buffer device to prevent the safety bar from bouncing up.

8. The lead-bismuth pile according to claim 1, characterized in that, It also includes a drive assembly and a power unit, which are disposed above the reactor container. The drive assembly clamps the safety bar, and the power unit drives the drive assembly to move along the extension direction of the safety bar. The drive assembly drives the safety bar to move along its extension direction so that it can insert into the reactor core or rise away from the reactor core. In the event of an accident, the drive assembly loses its clamping effect on the safety bar, and the safety bar falls freely.

9. The lead-bismuth pile according to claim 8, characterized in that, The drive assembly includes a gripper that holds the safety bar.

10. The lead-bismuth pile according to claim 8, characterized in that, It also includes a cover, which is disposed on the stack container and forms a seal on the stack container. The drive assembly is configured to pass through the cover, and a seal is provided at the location where it passes through the cover to form a seal between the two.

Images