A passive residual heat removal system and method for a mobile reactor

Abstract

The present invention discloses a mobile reactor passive residual heat removal system and method, the system includes a reactor main container, a reactor protection container and a heat-conducting rod, there is a certain gap between the reactor main container and the reactor protection container, the gap is connected to a heat-conducting oil pipeline, the heat-conducting oil pipeline is connected to the heat-conducting oil container, and an isolation valve is installed on the heat-conducting oil pipeline; one end of the heat-conducting rod is embedded in the reactor protection container, and the other end is buried underground; the mobile reactor passive residual heat removal system of the present invention can achieve the effect of timely opening of the valve under accident conditions without relying on any external intervention operation, avoiding the influence of human operation errors or valve electrical and mechanical failures, and using soil and groundwater sources as the ultimate heat sink. Compared with traditional passive residual heat removal systems, the environmental heat emission is low, the infrared stealth effect is good, and the concealment of land-based mobile lead-based micro-reactors can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of nuclear reactor safety technology, and in particular to a passive residual heat removal system and method for a movable reactor. Background Art

[0002] Nuclear energy is a crucial component of green, low-carbon energy. Small reactors are a hot topic in nuclear energy research and development both domestically and internationally. Microreactors (MRRs) with electrical power below 10MW and thermal power below 20MW are known as microreactors. Lead-based microreactors (lead or lead-bismuth) offer superior safety and high energy quality. Furthermore, lead-based reactors have extensive operational experience and a high level of technological maturity, making them a key area of ​​research for microreactors. Mobile, land-based microreactors can be used to provide energy security in remote inland areas and key bases.

[0003] Currently, residual heat removal in lead-based reactors typically uses ambient air or water in passive water tanks as the final heat sink. This heat is dissipated to the environment through a secondary system, the reactor vessel cooling system, and other processes, relying on natural air circulation or water evaporation. For example, the SVBR-100, a small lead-bismuth reactor developed by Rosatom, uses water as the final heat sink. Its passive system includes a condenser, a safety water tank, and control valves. Under accident conditions, the secondary circuit establishes natural circulation, using the safety water tank as the final heat sink to dissipate core residual heat, which ultimately diffuses into the environment through water vapor. Another example is the CLEAR-I, a lead-bismuth reactor developed by the Institute of Nuclear Safety and Technology of the Chinese Academy of Sciences, which uses air as the final heat sink. Its passive residual heat removal system consists of a hot air ascending duct, a cold air descending duct, and a chimney outside the containment. Under accident conditions, the core residual heat is removed by natural circulation within the air ducts and released to the environment.

[0004] The inventors discovered that current passive waste heat removal systems for lead-based reactors, which typically use air and water as their ultimate heat sinks, suffer from high heat emissions and poor infrared stealth. For specialized land-based mobile lead-based micro-reactors, infrared elimination should be fully considered to minimize heat emissions to the environment. However, existing passive waste heat removal systems are clearly unsuitable for heat removal from land-based mobile lead-based micro-reactors. Summary of the Invention

[0005] In response to the problems existing in the existing technology, the present invention proposes a passive residual heat removal system and method for a mobile reactor with soil and groundwater as the ultimate heat sink, aiming to reduce heat emissions to the environment under accident conditions, improve the concealment of the device, and enhance the safety and advancement of land-based mobile lead-based micro-reactors.

[0006] The technical solutions of the present invention are as follows:

[0007] In a first aspect of the present invention, a movable reactor passive residual heat removal system includes a reactor main vessel, a reactor protection vessel and a heat-conducting rod. A certain gap is provided between the reactor main vessel and the reactor protection vessel, and the gap is connected to a heat-conducting oil pipeline. The heat-conducting oil pipeline is connected to the heat-conducting oil container, and an isolation valve is installed on the heat-conducting oil pipeline. One end of the heat-conducting rod is embedded in the reactor protection vessel, and the other end is buried underground.

[0008] In some embodiments of the present invention, the isolation valve comprises an upper component, a lower component and an isolation valve housing, and the upper component and the lower component are both disposed in the isolation valve housing.

[0009] In some embodiments of the present invention, the upper component is a permanent magnet fixed in the isolation valve housing.

[0010] In some embodiments of the present invention, the lower component is an integrated component consisting of a soft magnetic material, a pre-compressed spring, a valve disc, and a valve body, and has no connection with the isolation valve housing.

[0011] In some embodiments of the present invention, the soft magnetic material is connected to a heat transfer component, and the other end of the heat transfer component is connected to the wall of the reactor main container.

[0012] In some embodiments of the present invention, the thermally conductive rod is buried 5-10 m underground.

[0013] In some embodiments of the present invention, the lower portion of the thermal oil container is thermal oil, and the upper portion is pressurized nitrogen.

[0014] In some embodiments of the present invention, under normal operating conditions, the gap between the reactor main vessel and the reactor protection vessel is filled with inert gas.

[0015] In a second aspect of the present invention, a method for removing passive residual heat from a mobile reactor is provided.

[0016] Under normal operating conditions, the isolation valve is closed, and the inert gas filled between the reactor main vessel and the reactor protection vessel increases the thermal resistance of heat transfer between the two, reducing the heat loss of the core;

[0017] Under accident conditions, the isolation valve opens, and heat transfer oil is injected into the gap between the reactor main vessel and the reactor protection vessel along the heat transfer oil pipeline. This allows the heat from the reactor main vessel to be transferred to the reactor protection vessel more quickly, and eventually transfers the heat into the ground through the heat transfer rods.

[0018] Furthermore, the opening and closing of the isolation valve is achieved according to whether the temperature of the soft magnetic material reaches its Curie temperature.

[0019] One or more technical solutions of the present invention have the following beneficial effects:

[0020] (1) The isolation valve used in the present invention utilizes the property of easy demagnetization of soft magnetic materials. According to its special structural design, the isolation valve can be automatically opened according to the wall temperature of the reactor main container without the need for an external power source.

[0021] (2) The mobile reactor passive residual heat removal system of the present invention can achieve the effect of timely opening of the valve under accident conditions without relying on any external intervention operation, avoiding the influence of human operation errors or valve electrical and mechanical failures; and uses soil and groundwater sources as the final heat sink. Compared with the traditional passive residual heat removal system, it has low environmental heat emissions and good infrared stealth effect. It is suitable for heat removal of land-based mobile lead-based micro-reactors, can effectively improve the concealment of land-based mobile lead-based micro-reactors, and thus improve the safety and advancement of land-based mobile lead-based micro-reactors.

[0022] (3) Under normal operating conditions, the gap between the reactor main container and the reactor protection container is filled with inert gas, which increases the heat transfer resistance between the reactor main container and the reactor protection container, reduces the heat loss of the core under normal operating conditions, and improves the economic efficiency of the reactor.

[0023] (4) The temperature threshold for opening the isolation valve of the present invention can be adjusted by the chemical composition and size of the magnet and the force of the pre-compression spring to meet different requirements for waste heat discharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of a passive residual heat removal system for a mobile reactor according to the present invention;

[0025] Figure 2 It is a structural schematic diagram of the isolation valve of the present invention.

[0026] In the figure: 1-thermal oil pipeline, 2-isolation valve, 3-reactor protection vessel, 4-reactor main vessel, 5-thermal rod, 6-pressurized nitrogen, 7-thermal oil, 8-core, 9-core cover, 10-permanent magnet, 11-soft magnetic material, 12-pre-compression spring, 13-valve disc, 14-valve body, 15-isolation valve housing, 16-heat transfer assembly. DETAILED DESCRIPTION

[0027] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0028] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0029] Example 1

[0030] In a typical embodiment of the present invention, a mobile reactor passive residual heat removal system is proposed, such as Figure 1 As shown, it includes a reactor main container 4, a reactor protection container 3 and a heat-conducting rod 5. The reactor main container 4 is arranged inside the reactor protection container 3, and there is a certain gap between the reactor main container 4 and the reactor protection container 3. Under normal operating conditions, the gap is filled with high thermal resistance working fluids such as inert gas, so that the heat transfer resistance between the reactor main container and the reactor protection container is relatively large, which reduces the heat loss of the core under normal operating conditions and improves the economy of the reactor; a core 8 is arranged in the reactor main container 4, and a stack cover 9 is arranged on the top; a hole is opened on the reactor protection container 3 to communicate with the heat-conducting oil pipeline 1, thereby realizing that the gap between the reactor main container 4 and the reactor protection container 3 is connected to the heat-conducting oil pipeline 1, the heat-conducting oil pipeline 1 is connected to the heat-conducting oil container, and an isolation valve 2 is installed on the heat-conducting oil pipeline 1; one end of the heat-conducting rod 5 is embedded in the reactor protection container, and the other end is buried underground to realize the introduction of heat into the underground.

[0031] like Figure 2 As shown, the isolation valve 2 includes an upper component, a lower component and an isolation valve housing 15, and the upper component and the lower component are both arranged in the isolation valve housing 15, wherein the upper component is a permanent magnet 10, which is fixed in the isolation valve housing 15, and the lower component is an integrated component composed of a soft magnetic material 11, a pre-compression spring 12, a valve disc 13, and a valve body 14, and has no connection with the isolation valve housing. Specifically, the soft magnetic material 11 is embedded in the upper part of the valve body 14, and two pre-compression springs 12 are arranged at intervals on the inner side of the soft magnetic material. The upper end of each spring is against the top of the permanent magnet, and the lower end is against the valve body. A valve disc 13 is arranged between the two pre-compression springs, and the valve disc is welded to the valve body 14.

[0032] The soft magnetic material 11 is connected to a heat transfer component 16, the other end of which is connected to the wall of the reactor main vessel 4. The temperature of the reactor main vessel 4 can be transferred to the soft magnetic material 11 in real time. It is easy to magnetize and demagnetize. When the temperature of the soft magnetic material reaches its own Curie temperature, the spontaneous magnetization disappears and it turns into paramagnetism.

[0033] In this embodiment, the heat transfer component 16 is made of 316 stainless steel, which has the advantages of good corrosion resistance, good high temperature resistance, good heat transfer performance, and low thermal resistance.

[0034] In this embodiment, since the thermal oil pipeline 1 needs to be provided with a hole on the wall surface of the reactor protection vessel 3 , the wall surface of the reactor protection vessel 3 needs to be further sealed.

[0035] The operating principle of isolation valve 2 is as follows: When the temperature of the soft magnetic material is below the Curie temperature, the upper and lower components of the isolation valve are connected primarily by the strong attraction between the magnets, and the isolation valve is closed. When the temperature of the soft magnetic material reaches the Curie temperature, the magnetism disappears. Under the weight of the isolation valve's lower component and the force of the pre-compressed spring, the lower component completely separates from the upper component and falls directly to the bottom of the isolation valve housing, opening the isolation valve. By adopting a mutually independent structure, the upper and lower components can be separated in the event of an emergency, preventing the soft magnetic material from being exposed to the strong magnetic field of the permanent magnet for a long time, which could cause re-magnetization and re-closure of the valve.

[0036] The temperature threshold at which the isolation valve opens can be adjusted by the magnet's chemical composition, size, and the force of the pre-compressed spring.

[0037] The heat conducting rod 5 can be made of stainless steel and buried 5-10 meters underground in the phreatic layer, where the underground water reserves are large, the external interference is small, and the water temperature is relatively stable.

[0038] The position of the thermal oil container is higher than the core 8. The reactor main container 4, the reactor protection container 3 and the core 8 are all located underground. The thermal oil container is filled with thermal oil 7. Furthermore, pressurized nitrogen is provided on the top of the thermal oil. When the isolation valve is in the open state, the thermal oil 7 can use its own gravity and the action of pressurized nitrogen to enter the gap between the reactor main container 4 and the reactor protection container 3 along the thermal oil pipe.

[0039] The working principle of the mobile reactor passive residual heat removal system of this embodiment is as follows:

[0040] Under normal operating conditions, the core temperature is within a safe range, the temperature of the soft magnetic material in the isolation valve is below the threshold, the magnets have a strong attraction, and the valve is closed. At this time, the high-thermal-resistance inert gas filling the gap between the reactor vessel and the reactor protection vessel increases the thermal resistance between the two, reducing core heat loss under normal operating conditions and improving the reactor's economic efficiency.

[0041] Under accident conditions, the core temperature cannot be properly discharged, causing the primary coolant temperature to rise, leading to an increase in the temperature of the reactor vessel's walls. This rise in wall temperature transfers heat to the soft magnetic material in the isolation valve through the heat transfer assembly. When the temperature exceeds its Curie temperature, the soft magnetic material loses its magnetism. At this point, under the force of the pre-compressed spring and the gravity of the lower assembly, the upper and lower assemblies of the isolation valve completely separate. The isolation valve opens, and under the influence of its own gravity and pressurized nitrogen, the thermal oil is injected along the thermal oil pipeline into the gap between the reactor vessel and the reactor protection vessel. This allows the heat from the primary circuit to be effectively transferred to the reactor protection vessel, and ultimately, through heat conduction, the heat is transferred via stainless steel heat conducting rods to the ultimate heat sink, the soil and groundwater source, completing the timely discharge of the core residual heat under accident conditions. Because the heat is ultimately discharged underground, it can provide excellent infrared concealment.

[0042] The mobile reactor passive residual heat removal system provided in this embodiment can achieve the effect of timely opening of valves under accident conditions without relying on any external intervention operation, avoiding the impact of human operational errors or valve electrical and mechanical failures, and uses soil and groundwater sources as the ultimate heat sink. Compared with traditional passive residual heat removal systems, it has low environmental heat emissions and good infrared stealth effect, which can effectively improve the concealment of land-based mobile lead-based micro-reactors.

[0043] Example 2

[0044] In a typical embodiment of the present invention, a method for removing passive residual heat from a mobile reactor is proposed.

[0045] Under normal operating conditions, the isolation valve is closed, and the inert gas filled between the reactor main vessel and the reactor protection vessel increases the thermal resistance of heat transfer between the two, reducing the heat loss of the core;

[0046] Under accident conditions, the isolation valve opens and the heat transfer oil is injected into the gap between the reactor main vessel and the reactor protection vessel along the heat transfer oil pipeline, so that the heat of the reactor main vessel is transferred to the reactor protection vessel, and finally the heat is transferred to the ground through the heat transfer rod.

[0047] Furthermore, the opening and closing of the isolation valve is achieved according to whether the temperature of the soft magnetic material reaches its Curie temperature.

[0048] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A mobile reactor passive residual heat removal system, characterized in that: The reactor comprises a main reactor vessel, a reactor protection vessel, and a heat-conducting rod. A certain gap is provided between the main reactor vessel and the reactor protection vessel, the gap being connected to a heat-conducting oil pipeline, the heat-conducting oil pipeline being connected to the heat-conducting oil vessel, and an isolation valve being installed on the heat-conducting oil pipeline. One end of the heat-conducting rod is embedded in the reactor protection vessel, and the other end is buried underground. The isolation valve includes an upper component, a lower component and an isolation valve shell. The upper component is a permanent magnet, and the lower component is an integrated component composed of soft magnetic material, a pre-compression spring, a valve disc and a valve body. It has no connection with the isolation valve shell. The soft magnetic material is embedded in the upper part of the valve body. Two pre-compression springs are arranged at intervals on the inner side of the soft magnetic material. The upper end of each spring is against the top of the permanent magnet, and the lower end is against the valve body. A valve disc is arranged between the two pre-compression springs and is welded to the valve body. The soft magnetic material is connected to the heat transfer component, and the other end of the heat transfer component is connected to the wall of the reactor main container.

2. The mobile reactor passive residual heat removal system according to claim 1, characterized in that: The upper assembly and the lower assembly are both arranged in the isolation valve housing.

3. The mobile reactor passive residual heat removal system according to claim 2, characterized in that: The permanent magnet is fixed in the isolation valve housing.

4. The mobile reactor passive residual heat removal system according to claim 1, wherein: The heat conducting rod is buried 5-10m underground.

5. The mobile reactor passive residual heat removal system according to claim 1, wherein: The lower part of the thermal oil container is thermal oil, and the upper part is pressurized nitrogen.

6. The mobile reactor passive residual heat removal system according to claim 1, characterized in that: Under normal operating conditions, the gap between the reactor main vessel and the reactor protection vessel is filled with inert gas.

7. A method for removing passive residual heat from a mobile reactor, implemented by using the passive residual heat removal system for a mobile reactor according to any one of claims 1 to 6, characterized in that: Under normal operating conditions, the isolation valve is closed, and the inert gas filled between the reactor main vessel and the reactor protection vessel increases the thermal resistance of heat transfer between the two, reducing the heat loss of the core; Under accident conditions, the isolation valve opens and the heat transfer oil is injected into the gap between the reactor main vessel and the reactor protection vessel along the heat transfer oil pipeline, so that the heat of the reactor main vessel is transferred to the reactor protection vessel, and finally the heat is transferred to the ground through the heat transfer rod.

8. The method for removing passive residual heat from a mobile reactor according to claim 7, wherein: The opening and closing of the isolation valve is achieved according to whether the temperature of the soft magnetic material reaches its Curie temperature.

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