Lead-based fast neutron high-flux research reactor with coolant flowing in partitioned manner

Abstract

The invention relates to the technical field of nuclear reactors, in particular to a lead-based fast neutron high-flux research reactor with coolant flowing in different areas, which comprises a reactor container provided with a first coolant flow channel and a second coolant flow channel which are connected in parallel; the fuel assembly is loaded with nuclear fuel, is mounted in the reactor container and is positioned at the outlet of the first coolant flow channel; the reflecting layer assembly is a structural assembly, is mounted in the reactor container, is arranged outside the fuel assembly in a surrounding manner, and is positioned at an outlet of the second coolant runner; the lead-based cooling agent output from the second cooling agent flow channel flows to an outlet of the first cooling agent flow channel after flowing through the reflecting layer assembly, and the flow of the lead-based cooling agent flowing through the second cooling agent flow channel is smaller than that of the lead-based cooling agent flowing through the first cooling agent flow channel. The design and manufacturing difficulty of the fuel assembly and the reflecting layer assembly can be reduced.

Description

Technical Field

[0001] This invention relates to the field of nuclear reactor technology, specifically to a lead-based fast neutron high-flux research reactor with coolant zoned flow. Background Technology

[0002] "Fast neutron high flux" refers to a special nuclear environment that can generate an extremely dense high-energy neutron field (where the proportion of neutrons with energies higher than 0.1 MeV is greater than 70%). High-flux research reactors are large-scale, comprehensive nuclear facilities that provide high-quality neutron sources and realistic service environments for various types of reactors. They meet the requirements for long-term irradiation testing and performance evaluation of advanced nuclear fuels and materials, key technology experiments for advanced nuclear reactors, and cutting-edge basic research in fields such as neutron science, materials science, energy science, and biological science. They are essential major scientific and technological infrastructure for the development of advanced nuclear energy technologies. Currently, most of the research reactors built are water-cooled thermal neutron reactors. Globally, only one metal-cooled fast neutron high flux research reactor is operational, located in Russia. Fast neutron irradiation resources are extremely scarce, severely restricting the innovative development of advanced nuclear energy technologies and innovative nuclear reactor technologies based on the fast neutron spectrum.

[0003] Against this backdrop, to support the long-term development of advanced nuclear energy technologies, primarily fast neutron reactors, and other innovative reactor technologies, it is necessary to construct future metal-cooled multi-purpose fast neutron high-flux research reactors. For example, a sodium-cooled fast neutron high-flux research reactor currently under construction has a thermal power of 150MW and a maximum irradiance of 35 dpa / year. It adopts a pressure vessel-type three-loop design, where the primary loop coolant is high-temperature liquid metallic sodium, the intermediate loop coolant is sodium, and the tertiary loop system uses high-temperature steam. A sodium-cooled fast neutron high-flux research reactor soon to be constructed has a thermal power of 300MW and a maximum core irradiance of 30 dpa / year, employing a pool-type three-loop design similar to the aforementioned sodium-cooled fast neutron reactor. An accelerator-driven lead-based cold fast neutron high-flux research reactor, whose design has been approved, has a thermal power of 100MW and a maximum irradiance of over 20 dpa / year, employing an integral vessel-type two-loop design.

[0004] Compared to sodium-cooled fast neutron high-flux research reactors, lead-based fast neutron high-flux research reactors operate with a lower primary coolant temperature and at atmospheric pressure. Lead-based coolants do not undergo violent chemical reactions with air or water, offering significant safety advantages and representing an important development direction for metal-cooled fast neutron high-flux research reactors. Compared to traditional power reactors, high-flux research reactors must first meet the specific requirements for the installation, commissioning, operation, and testing of irradiation experimental devices. The coolant flow direction and flow rate not only alter the overall structure of the high-flux research reactor but also affect the installation, operation, and testing of the irradiation experimental device. Therefore, the coolant flow scheme of a high-flux research reactor has a significant impact on its performance.

[0005] Among them, the metal-cooled high-flux fast neutron research reactors in service and under construction all adopt a coolant upward flow design scheme similar to that of power reactors. However, if heavy metal lead-based alloys are used as coolants in metal-cooled high-flux fast neutron research reactors, the following problems exist: 1) Lead-based coolants have a density of over 11.0 grams per cubic centimeter, resulting in significant buoyancy. This places very high demands on fuel assemblies that are frequently replaced and contain fissile nuclear fuel, as well as on their loading and unloading operations and refueling equipment. If the coolant flows upward rapidly, it will further increase the upward force, making the design and manufacturing of fuel assemblies and their refueling process more complex, technically challenging, and technically demanding, making practical application difficult; 2) In order to reduce the radiation damage to the in-core basket and reactor vessel and meet the flexibility requirements of irradiation experiments, a large number of reflector assemblies (structural assemblies) are usually installed on the core, resulting in a very large flow rate of coolant around the core. For high-flux research reactors using heavy metal lead-based coolants, this will significantly increase the performance requirements and manufacturing difficulty of the main pump.

[0006] Therefore, it is essential to explore innovative coolant flow design schemes for lead-based fast neutron high flux research reactors, overcome the problems and shortcomings of existing coolant upward flow design schemes for lead-based fast neutron high flux research reactors, improve engineering feasibility, and strongly support subsequent engineering construction. Summary of the Invention

[0007] This invention provides a lead-based fast neutron high-flux research reactor with zoned coolant flow. It can effectively solve the adverse effects of the high buoyancy characteristics of heavy metal lead-based coolant on the design, manufacturing, and loading / unloading operations of fuel assemblies and reflector assemblies. It reduces the design and manufacturing difficulty of fuel assemblies and reflector assemblies, and effectively reduces the flow rate of high-density lead-based coolant while ensuring reactor operation safety. This reduces the flow requirements of the main pump, thereby significantly improving the engineering feasibility of the lead-based fast neutron high-flux research reactor.

[0008] This invention is achieved through the following technical solution:

[0009] This invention provides a lead-based fast neutron high-flux research reactor with zoned coolant flow, comprising: a reactor vessel having a first coolant flow channel and a second coolant flow channel, the first coolant flow channel and the second coolant flow channel being connected in parallel; a fuel assembly loaded with nuclear fuel, installed inside the reactor vessel and located at the outlet of the first coolant flow channel; and a reflector assembly, a structural assembly, installed inside the reactor vessel and surrounding the fuel assembly, located at the outlet of the second coolant flow channel; wherein, the lead-based coolant output from the second coolant flow channel flows through the reflector assembly and then flows to the outlet of the first coolant flow channel, and the flow rate of the lead-based coolant flowing through the second coolant flow channel is less than that flowing through the first coolant flow channel.

[0010] The lead-based fast neutron high-flux research reactor with zoned coolant flow provided by this invention includes a reactor vessel, fuel assemblies, and a reflector assembly. The fuel assemblies are loaded with nuclear fuel, and the reflector assembly is a structural component that surrounds the fuel assemblies. Thus, according to the type and purpose of the reactor assemblies, the reactor core is divided from the inside out into a fuel assembly area with a high switching frequency and a reflector assembly area with an extremely low switching frequency. This allows for different methods and technical approaches to address the high buoyancy problem caused by heavy metal lead-based coolants.

[0011] The fuel assembly region, located in the core center, experiences high power density and a large neutron flux rate due to nuclear fission. Lead-based coolant exits from the first coolant channel and flows through the fuel assemblies, carrying away the heat generated by the nuclear fission reaction and ensuring that the core temperature and cladding temperature do not exceed design limits. The reflector assembly region, located on the periphery of the core, does not contain fissile or fissile nuclear fuel and does not undergo nuclear fission, generating very little heat. Lead-based coolant exits from the second coolant channel and flows through and cools the reflector assembly, achieving zoned flow of lead-based coolant. After passing through the reflector assembly, the coolant finally flows through the fuel assemblies. This zoned flow increases the lead-based coolant flow rate in the fuel assembly region, reducing the total reactor coolant flow rate and consequently lowering the flow requirements for the lead-based main pump. This significantly improves the engineering feasibility of the lead-based fast neutron high-flux research reactor.

[0012] Meanwhile, when the lead-based coolant flows, the flow rate of lead-based coolant flowing through the second coolant channel is less than that flowing through the first coolant channel. Most of it flows directly through the fuel assembly, and a small portion flows through the reflector assembly. Furthermore, the lead-based coolant output from the second coolant channel also eventually flows through the fuel assembly. This allows the lead-based coolant to provide a greater downward force when flowing through the fuel assembly, thereby overcoming the high buoyancy problem caused by lead-based coolant. This effectively solves the high buoyancy characteristics of heavy metal lead-based coolant, reducing the adverse effects on the design and manufacturing of fuel assemblies and reflector assemblies, as well as their loading and unloading operations, and lowering the overall design and manufacturing difficulty of fuel assemblies and reflector assemblies.

[0013] Therefore, the lead-based fast neutron high flux research reactor with coolant zonal flow provided by this invention can effectively solve the adverse effects of the high buoyancy characteristics of heavy metal lead-based coolant on the design and manufacturing of fuel assemblies and reflector assemblies, as well as their loading and unloading operations. It reduces the design and manufacturing difficulty of fuel assemblies and reflector assemblies, and effectively reduces the flow rate of high-density lead-based coolant while ensuring reactor operation safety, thereby reducing the flow requirements of the main pump and significantly improving the engineering feasibility of the lead-based fast neutron high flux research reactor.

[0014] In an optional embodiment of this application, an inner basket is further included. The inner basket is installed inside the reactor vessel, and a flow gap exists between its upper outer periphery and the side wall of the reactor vessel. The first coolant channel is a cavity formed by the upper end of the inner basket and the upper end of the reactor vessel. The fuel assembly is installed in the lower middle part of the inner cavity of the inner basket, and the lower end of the fuel assembly extends to the outside of the lower end of the inner basket. The inlet of the second coolant channel communicates with the flow gap between the upper outer periphery of the inner basket and the side wall of the reactor vessel, and the outlet is located at the lower end of the inner basket. This facilitates the installation of the fuel assembly and the reflector assembly, and also facilitates the direct separation of the first coolant channel and the second coolant channel within the reactor vessel.

[0015] In an optional embodiment of this application, an outer basket is further included, which is spaced outside the inner basket, and the second coolant channel is the gap between the inner basket and the outer basket, so as to separate a second coolant channel within the reactor vessel.

[0016] In an optional embodiment of this application, the inner basket is provided with a first grid plate, and the fuel assembly and the reflective layer assembly are both mounted on the first grid plate to facilitate the installation and fixing of the fuel assembly and the reflective layer assembly.

[0017] In an optional embodiment of this application, the first grid plate and the lower end of the inner basket form a diversion chamber, and the outlet of the second coolant channel is disposed on the side wall of the diversion chamber, so as to facilitate the second coolant cold channel to be led to the area below the first grid plate.

[0018] In an optional embodiment of this application, the lower end of the reflective layer assembly extends into the diversion chamber to ensure that lead-based coolant output from the second coolant channel can flow to the reflective layer assembly.

[0019] In an optional embodiment of this application, the outer basket is provided with a second grid plate, and the lower end of the fuel assembly extends from the lower end of the inner basket to the lower side of the second grid plate, so as to fix the fuel assembly simultaneously by the second grid plate and the first grid plate, ensuring the stability of the fuel assembly installation, and further providing the fuel assembly with the ability to overcome the large buoyancy caused by the lead-based coolant.

[0020] In an optional embodiment of this application, the outer basket is spaced apart from the side wall of the reactor vessel so that lead-based coolant can circulate through the outer wall of the outer basket.

[0021] In an optional embodiment of this application, a coolant inlet is provided at the upper part of the reactor vessel, and the inlets of the first coolant channel and the second coolant channel are both connected to the coolant inlet to ensure that the lead-based coolant entering the reactor vessel can flow into the first coolant channel and the second coolant channel simultaneously.

[0022] In an optional embodiment of this application, the reactor vessel is further provided with a coolant outlet, which communicates with the cavity between the outer basket and the side wall of the reactor vessel, so as to facilitate the export of lead-based coolant from the reactor vessel.

[0023] In an optional embodiment of this application, the coolant outlet is located at the upper part of the reactor vessel and below the coolant inlet, so that the lead-based coolant flowing through the fuel assembly flows upward for a certain distance before flowing out of the reactor vessel, ensuring that the lead-based coolant can adequately cool the fuel assembly and the reflector assembly.

[0024] In an optional embodiment of this application, a support boss is provided at the upper end of the inner cavity of the reactor vessel, and the upper end of the outer basket is hung on the support boss to facilitate the installation of the inner basket and the outer basket respectively.

[0025] In an optional embodiment of this application, the upper end of the reactor vessel is fitted with a sealing valve to facilitate the replacement of components within the reactor vessel.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0027] 1. The lead-based fast neutron high-flux research reactor with zoned coolant flow provided by the present invention includes a reactor vessel, fuel assemblies, and a reflector assembly. The fuel assemblies are loaded with nuclear fuel, and the reflector assembly is a structural assembly that surrounds the fuel assemblies. Thus, according to the type and purpose of the reactor assemblies, the reactor core is divided from the inside out into a fuel assembly area with a high switching frequency and a reflector assembly area with an extremely low switching frequency. This allows for different methods and technical approaches to solve the high buoyancy problem caused by heavy metal lead-based coolants.

[0028] 2. The lead-based fast neutron high-flux research reactor with zoned coolant flow provided by this invention has its fuel assembly region located in the core center. Due to the high power density and large neutron flux rate resulting from nuclear fission, the fuel assembly region is located in this central region. The lead-based coolant exits from the first coolant channel outlet and flows through the fuel assemblies. This high-speed flow of the lead-based coolant removes the heat generated by the nuclear fission reaction, ensuring that the core temperature of the fuel assemblies and the cladding temperature do not exceed design limits. The reflector assembly region, located in the outer periphery of the core, does not contain fissile or easily fissile nuclear fuel and therefore does not undergo nuclear fission reactions. The heat generated is thus neutralized. The amount is very small. The lead-based coolant is output from the outlet of the second coolant channel to flow through and cool the reflector assembly, so as to achieve the zoned flow of the lead-based coolant. After flowing through the reflector assembly, the lead-based coolant finally flows through the fuel assembly. While the zoned flow is achieved, the flow rate of the lead-based coolant in the fuel assembly area can be increased, which can reduce the total flow rate of the reactor coolant, thereby reducing the flow rate requirement of the lead-based main pump. Ultimately, while ensuring the safe operation of the reactor, the flow rate of the high-density lead-based coolant is effectively reduced, thereby significantly improving the engineering feasibility of the lead-based fast neutron high-flux research reactor.

[0029] 3. The lead-based fast neutron high-flux research reactor with zoned coolant flow provided by this invention has a lead-based coolant flow rate through the second coolant channel that is less than that through the first coolant channel. Most of the coolant flows directly through the fuel assembly, and a small portion flows through the reflector assembly. The lead-based coolant output from the second coolant channel also eventually flows through the fuel assembly. This allows the lead-based coolant to provide a greater downward force when flowing through the fuel assembly, thereby overcoming the high buoyancy problem caused by the lead-based coolant. It can effectively solve the adverse effects of the high buoyancy characteristics of heavy metal lead-based coolant on the design and manufacturing of fuel assemblies and reflector assemblies, as well as their loading and unloading operations, and reduce the design and manufacturing difficulty of fuel assemblies and reflector assemblies. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] In the attached diagram:

[0032] Figure 1 This is a schematic diagram of the structure of a lead-based fast neutron high-flux research reactor with coolant partitioned flow, provided in an embodiment of the present invention.

[0033] The attached figures include reference numerals and their corresponding component names:

[0034] 1-Reactor vessel, 2-First coolant channel, 3-Second coolant channel, 5-Fuel assembly, 6-Reflector layer assembly, 7-Inner basket, 8-Outer basket, 9-First grid plate, 10-Diverter chamber, 11-Second grid plate, 12-Coolant inlet, 13-Coolant outlet, 14-Support boss, 15-Sealing plug. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0037] It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0038] In the description of the embodiments of this application, the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of this application is usually placed in when in use, or the orientation or positional relationship that is commonly understood by those skilled in the art. It is only for the convenience of describing this application and simplifying the description, and is not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0039] In the description of this application, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0040] Example

[0041] Combination Figure 1This embodiment provides a lead-based fast neutron high-flux research reactor with zoned coolant flow, comprising: a reactor vessel 1, having a first coolant channel 2 and a second coolant channel 3, the first coolant channel 2 and the second coolant channel 3 being connected in parallel; a fuel assembly 5, loaded with nuclear fuel, installed inside the reactor vessel 1 and located at the outlet of the first coolant channel 2; and a reflector assembly 6, a structural assembly, installed inside the reactor vessel 1 and surrounding the fuel assembly 5, located at the outlet of the second coolant channel 3; wherein, the lead-based coolant output from the second coolant channel 3 flows through the reflector assembly 6 and then flows to the outlet of the first coolant channel 2, and the flow rate of the lead-based coolant flowing through the second coolant channel 3 is less than that flowing through the first coolant channel 2.

[0042] In other words, according to the type and purpose of the reactor loading components, this embodiment divides the reactor core into two zones from the inside out: zone 5, the fuel assembly with a high switching frequency, and zone 6, the reflector assembly with an extremely low switching frequency. This allows for different methods and technical approaches to address the high buoyancy problem caused by heavy metal lead-based coolants.

[0043] It is understandable that fuel assembly 5 is located in the central region of the reactor core, and mainly houses fuel assemblies 5 that are loaded with fissile nuclear fuel. Because nuclear fission has a high power density and a large neutron flux, in this embodiment, lead-based coolant enters from the top of fuel assembly 5 and flows out from the bottom. The high-speed flow of lead-based coolant carries away the heat generated by the nuclear fission reaction of the nuclear fuel, ensuring that the core temperature and cladding temperature of fuel assembly 5 do not exceed the design limits.

[0044] Meanwhile, the reflector assembly 6 area is located in the outer periphery of the reactor core, where reflector assembly 6 is mainly arranged. Reflector assembly 6 does not carry fissile or fissile nuclear fuel and is mainly composed of structural materials such as stainless steel. Liquid lead-based coolant can flow inside, so no nuclear fission reaction will occur and very little heat will be generated. The lead-based coolant flows in from the bottom of reflector assembly 6 and flows out from the top, slowly cooling reflector assembly 6.

[0045] In this embodiment, to achieve a top-to-bottom flow of lead-based coolant in fuel assembly 5 and a bottom-to-top flow of lead-based coolant in reflector assembly 6, the core basket is designed with two layers: an inner basket adjacent to the core and an outer basket adjacent to the reactor vessel 1. The bottoms of the inner and outer baskets form a sealed flow distribution chamber 10, and the bottom of the outer basket and the reactor vessel 1 form a lower chamber. Specifically:

[0046] This embodiment also includes an inner basket 7, which is installed inside the reactor vessel 1, and has a flow gap between its upper outer periphery and the side wall of the reactor vessel 1; the first coolant channel 2 is a cavity formed by the upper end of the inner basket 7 and the upper end of the reactor vessel 1; the fuel assembly 5 is installed in the lower middle part of the inner cavity of the inner basket 7, and the lower end of the fuel assembly 5 extends to the lower end of the inner basket 7; the inlet of the second coolant channel 3 communicates with the flow gap between the upper outer periphery of the inner basket 7 and the side wall of the reactor vessel 1, and the outlet is located at the lower end of the inner basket 7, which facilitates the installation of the fuel assembly 5 and the reflector assembly 6, and facilitates the direct separation of the first coolant channel 2 and the second coolant channel 3 inside the reactor vessel 1.

[0047] It is known that the inner basket 7 is provided with a first grid plate 9, and the fuel assembly 5 and the reflective layer assembly 6 are both installed on the first grid plate 9 to facilitate the installation and fixing of the fuel assembly 5 and the reflective layer assembly 6.

[0048] Generally, the first grid plate 9 and the lower end of the inner basket 7 form a diversion cavity 10 chamber, and the outlet of the second coolant flow channel 3 is located on the side wall of the diversion cavity 10 chamber, so as to facilitate the second coolant cold flow channel to be led to the area below the first grid plate 9.

[0049] This embodiment also includes an outer basket 8, which is spaced outside the inner basket 7, and the second coolant channel 3 is the gap between the inner basket 7 and the outer basket 8, so as to separate the second coolant channel 3 in the reactor vessel 1.

[0050] Correspondingly, the outer basket 8 is provided with a second grid plate 11, and the lower end of the fuel assembly 5 extends from the lower end of the inner basket 7 to the lower side of the second grid plate 11, so as to fix the fuel assembly 5 simultaneously through the second grid plate 11 and the first grid plate 9, ensuring the stability of the fuel assembly 5 installation, and further providing the fuel assembly 5 with the ability to overcome the large buoyancy caused by the lead-based coolant.

[0051] Meanwhile, the outer basket 8 is spaced apart from the side wall of the reactor vessel 1 so that lead-based coolant can circulate through the outer wall of the outer basket 8.

[0052] The lower end of the reflective layer assembly 6 extends into the chamber of the diversion cavity 10 to ensure that the lead-based coolant output from the second coolant channel 3 can flow to the reflective layer assembly 6.

[0053] It should be noted that, at the upper part of the reactor core, the inner basket 7 is higher than the outer basket 8; at the lower part of the reactor core, the inner basket 7 is connected to the outer basket 8, and the bottom side of the inner basket 7 is provided with coolant flow holes; both the inner basket 7 and the outer basket 8 are provided with grid plates, and the inner basket 7, the first grid plate 9, and the second grid plate 11 together constitute the lead-based coolant distribution chamber 10 at the lower part of the reactor core, and the second grid plate 11 and the lower end of the reactor vessel 1 form a lower chamber.

[0054] For the reflector assembly 6, which is located in the outer region of the reactor core and has a very low switching frequency, the reflector assembly 6 is directly fixed to the bottom grid plate of the inner basket 7. For the fuel assembly 5, which is located in the central region of the reactor core and has a high switching frequency, the length of the lower tube of the fuel assembly 5 is extended, passing through the lower flow chamber 10 of the reactor core. The lower tube of the fuel assembly 5 is gripped in the flow chamber 10, and the force formed by the downward flow of lead-based coolant is used to overcome the problem of high buoyancy caused by the lead-based coolant.

[0055] This results in the lower end of the reflective layer assembly 6 being located within the flow divider chamber 10, and the lower end of the fuel assembly 5 passing through the flow divider chamber 10, with its outlet located in the lower chamber. The fuel assembly 5 is supported by the first grid plate 9 and the second grid plate 11, while the reflective layer assembly 6 is supported by the first grid plate 9.

[0056] It should be understood that a coolant inlet 12 is provided at the upper part of the reactor vessel 1, and the inlets of the first coolant channel 2 and the second coolant channel 3 are both connected to the coolant inlet 12 to ensure that the lead-based coolant entering the reactor vessel 1 can flow into the first coolant channel 2 and the second coolant channel 3 simultaneously. That is, the top of the inner basket 7 is located at the coolant inlet 12.

[0057] Meanwhile, the reactor vessel 1 is also provided with a coolant outlet 13, which is connected to the cavity between the outer basket 8 and the side wall of the reactor vessel 1, so as to facilitate the export of lead-based coolant from the reactor vessel 1.

[0058] Typically, the coolant outlet 13 is located at the upper part of the reactor vessel 1 and below the coolant inlet 12, so that the lead-based coolant flowing through the fuel assembly 5 flows upward for a certain distance before flowing out of the reactor vessel 1, ensuring that the lead-based coolant can adequately cool the fuel assembly 5 and the reflector assembly 6.

[0059] The reactor vessel 1 has a supporting boss 14 at the upper end of its inner cavity. The upper end of the outer basket 8 is hung on the supporting boss 14 to facilitate the installation of the inner basket 7 and the outer basket 8. Specifically, in this embodiment, the reactor vessel 1 has a smaller lower outer diameter and a larger upper outer diameter. The change in outer diameter forms the supporting boss 14, which supports the inner basket 7 and the outer basket 8 of the reactor core. That is, the top of the outer basket 8 is suspended from the supporting boss 14. The supporting boss 14 is positioned between the coolant inlet 12 and the coolant outlet 13 to facilitate the layout of the flow channels.

[0060] In addition, the upper end of the reactor vessel 1 is equipped with a sealing plug 15 to facilitate the replacement of components inside the reactor vessel 1.

[0061] In summary, this embodiment provides a lead-based fast neutron high-flux research reactor with coolant partitioned flow. The lead-based fast neutron high-flux research reactor with coolant partitioned flow provided by this invention includes a reactor vessel 1, fuel assemblies 5, and a reflector assembly 6. The fuel assembly 5 is loaded with nuclear fuel, and the reflector assembly 6 is a structural assembly that surrounds the fuel assembly 5.

[0062] During reactor operation, the cryogenic lead-based coolant is directly diverted at the inlet of reactor vessel 1, with most of it entering the inner basket 7 and the remainder entering the annular cavity (second coolant channel 3) between the inner basket 7 and the outer basket 8. The cryogenic lead-based coolant entering the inner core basket 7 enters from the top of the fuel assembly 5, flows rapidly downward to cool the fuel assembly 5, and flows out from the bottom into the reactor lower chamber. The cryogenic lead-based coolant entering the annular cavity of the inner basket 7 and outer basket 8 flows downward through the coolant channel at the bottom of the inner basket 7 into the distribution cavity 10, then enters from the lower inlet of the reflector assembly 6, flows upward to cool the reflector assembly 6, flows out from the top of the reflector assembly 6, mixes with the lead-based coolant in the upper part of the core (lead-based coolant output from the first coolant channel 2), then enters from the top of the fuel assembly 5 again, flows rapidly downward to carry away the heat generated by the nuclear fission reaction of the fuel assembly 5, and then flows into the reactor lower chamber and is mixed. After all the coolant is fully mixed in the reactor lower chamber, it flows upward through the annular cavity (second coolant channel 3) between the outer basket 8 and the reactor vessel 1, and finally flows out from the coolant outlet 13 of the reactor vessel 1.

[0063] In this process, the lead-based coolant is output from the outlet of the second coolant channel to flow through and cool the reflector assembly 6, thereby achieving zoned flow of the lead-based coolant. After flowing through the reflector assembly 6, the lead-based coolant finally flows through the fuel assembly 5. While achieving zoned flow, the flow rate of the lead-based coolant in the fuel assembly 5 region can be increased, which can reduce the total flow rate of the reactor coolant and thus reduce the flow requirement of the lead-based main pump, thereby significantly improving the engineering feasibility of the lead-based fast neutron high flux research reactor.

[0064] Meanwhile, when the lead-based coolant is flowing, the flow rate of the lead-based coolant flowing through the second coolant channel 3 is less than that flowing through the first coolant channel 2, and the lead-based coolant output from the second coolant channel 3 also flows through the fuel assembly 5. This allows the lead-based coolant to provide a greater downward force when flowing through the fuel assembly 5. In addition, the clamping of the fuel assembly 5 by the first grid plate 9 and the second grid plate 11 overcomes the problem of high buoyancy caused by the lead-based coolant. This effectively solves the many adverse effects on the design, manufacturing, and loading / unloading operations of the fuel assembly 5 and the reflector assembly 6 caused by the high buoyancy characteristics of the heavy metal lead-based coolant, and reduces the design and manufacturing difficulty of the fuel assembly 5 and the reflector assembly 6.

[0065] In summary, the lead-based fast neutron high-flux research reactor with zoned coolant flow provided in this embodiment can effectively solve the adverse effects of the high buoyancy characteristics of heavy metal lead-based coolant on the design, manufacturing, and loading / unloading operations of fuel assembly 5 and reflector assembly 6. It reduces the overall design and manufacturing difficulty of fuel assembly 5 and reflector assembly 6, and effectively reduces the flow rate of high-density lead-based coolant while ensuring reactor operation safety, thereby reducing the flow requirements of lead-based main pumps and significantly improving the engineering feasibility of the lead-based fast neutron high-flux research reactor.

[0066] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A lead-based fast neutron high-flux research reactor with coolant zoned flow, characterized in that, include: The reactor vessel (1) is provided with a first coolant channel (2) and a second coolant channel (3), wherein the first coolant channel (2) and the second coolant channel (3) are connected in parallel; Fuel assembly (5), loaded with nuclear fuel, is installed inside the reactor vessel (1) and located at the outlet of the first coolant channel (2); The reflector assembly (6) is a structural assembly installed inside the reactor vessel (1) and surrounding the fuel assembly (5), located at the outlet of the second coolant channel (3); The lead-based coolant output from the second coolant channel (3) flows through the reflective layer assembly (6) and then flows to the outlet of the first coolant channel (2), and the flow rate of the lead-based coolant flowing through the second coolant channel (3) is less than that flowing through the first coolant channel (2).

2. The lead-based fast neutron high-flux research reactor with coolant zoned flow according to claim 1, characterized in that, It also includes an inner basket (7), which is installed inside the reactor vessel (1) and has a flow gap between its upper outer periphery and the side wall of the reactor vessel (1); The first coolant channel (2) is the cavity formed by the upper end of the inner basket (7) and the upper end of the reactor vessel (1); The fuel assembly (5) is installed in the lower middle part of the inner cavity of the inner basket (7), and the lower end of the fuel assembly (5) extends to the outside of the lower end of the inner basket (7); The inlet of the second coolant channel (3) is connected to the flow gap between the outer periphery of the upper end of the inner basket (7) and the side wall of the reactor vessel (1), and the outlet is located at the lower end of the inner basket (7).

3. The lead-based fast neutron high-flux research reactor with coolant zoned flow according to claim 2, characterized in that, It also includes an outer basket (8), which is spaced outside the inner basket (7), and the second coolant channel (3) is the gap between the inner basket (7) and the outer basket (8).

4. The lead-based fast neutron high-flux research reactor with coolant zoned flow according to claim 3, characterized in that, The inner basket (7) is provided with a first grid plate (9), and the fuel assembly (5) and the reflective layer assembly (6) are both installed on the first grid plate (9).

5. The lead-based fast neutron high-flux research reactor with coolant zoned flow according to claim 4, characterized in that, The first grid plate (9) and the lower end of the inner basket (7) form a diversion cavity (10) chamber, and the outlet of the second coolant channel (3) is located on the side wall of the diversion cavity (10) chamber.

6. The lead-based fast neutron high-flux research reactor with coolant zoned flow according to claim 5, characterized in that, The lower end of the reflective layer assembly (6) extends into the chamber of the diversion cavity (10).

7. The lead-based fast neutron high-flux research reactor with coolant zoned flow according to claim 3, characterized in that, The outer basket (8) is provided with a second grid plate (11), and the lower end of the fuel assembly (5) extends from the lower end of the inner basket (7) to the lower side of the second grid plate (11).

8. The lead-based fast neutron high-flux research reactor with coolant zoned flow according to claim 3, characterized in that, The outer basket (8) is spaced apart from the side wall of the reactor vessel (1).

9. The lead-based fast neutron high-flux research reactor with coolant zoned flow according to claim 8, characterized in that, The reactor vessel (1) is provided with a coolant inlet (12) at the top, and the inlets of the first coolant channel (2) and the second coolant channel (3) are connected to the coolant inlet (12).

10. The lead-based fast neutron high-flux research reactor with coolant zoned flow according to claim 9, characterized in that, The reactor vessel (1) is also provided with a coolant outlet (13), which is connected to the cavity between the outer basket (8) and the side wall of the reactor vessel (1).

11. The lead-based fast neutron high-flux research reactor with coolant zoned flow according to claim 10, characterized in that, The coolant outlet (13) is located at the top of the reactor vessel (1) and below the coolant inlet (12).

12. The lead-based fast neutron high-flux research reactor with coolant zoned flow according to claim 3, characterized in that, The upper end of the inner cavity of the reactor vessel (1) is provided with a support boss (14), and the upper end of the outer basket (8) is hung on the support boss (14).

13. The lead-based fast neutron high-flux research reactor with coolant zoned flow according to any one of claims 1 to 12, characterized in that, The upper end of the reactor vessel (1) is fitted with a sealing plug (15).

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