Safety assembly, lead-cooled fast neutron reactor and passive negative reactivity feedback method

Abstract

The invention relates to the technical field of nuclear reactor design, in particular to a safety assembly, a lead-cooled fast neutron reactor and a passive negative reactivity feedback method. The safety assembly comprises a first positioning piece, a second positioning piece and a containing piece. The first positioning piece and the second positioning piece are respectively connected with the accommodating piece so as to position the two ends of the accommodating piece in the linear direction, the accommodating piece is provided with an accommodating cavity for accommodating a coolant, and one end of the accommodating cavity in the length direction is communicated with the outside of the accommodating piece. The safety assembly is applied to the lead-cooled fast neutron reactor to serve as a safety barrier on the periphery of the reactor core, passive negative reactivity can be rapidly introduced, the structure is simple, implementation is convenient and fast, the nuclear reactor design specification and related technical requirements can be better met, and safety and reliability are further improved.

Description

Technical Field

[0001] This application relates to the field of nuclear reactor design technology, specifically to safety components, lead-cooled fast neutron reactors, and passive negative reactive feedback methods. Background Technology

[0002] Lead-cooled fast neutron reactors use pure lead or lead-based alloys as coolants, offering significant advantages such as simple system configuration and natural safety. They are one of the most promising and realistic fourth-generation nuclear power reactor types. Reactivity control is the prerequisite and foundation for the safe operation of nuclear reactors. Compared to light water-cooled thermal neutron reactors, lead-cooled fast neutron reactors have the following characteristics in terms of reactivity control: 1) High nuclear fuel enrichment, hard neutron spectrum, small proportion of delayed neutrons, and short average neutron lifetime; 2) No moderator in the core, very small proportion of thermal neutrons, and small reactivity fluctuations throughout the lifetime; 3) Long mean free path of neutrons in the core, resulting in significant neutron leakage at the periphery; 4) Lead-based coolants have high mass density and are invisible, making it impossible to use soluble poisons (such as boric acid) commonly used in pressurized water reactors to control residual reactivity in the core. These characteristics of lead-cooled fast neutron reactors place extremely high demands on the reliability and versatility of their reactivity control.

[0003] There are two main types of reactivity control in metal-cooled fast neutron reactors: removing core fuel elements and inserting neutron absorbers into the core. For example, the US EBR-II reactor uses the first reactivity control method, while the most widely used is the latter, namely, inserting or removing neutron absorbers. Using control rods to control the long-term stable operation of the nuclear reactor is the primary control method for metal-cooled fast neutron reactors. The main characteristics of control rods are fast control speed and high reliability. They can be used to compensate for reactor temperature effects related to power changes, reactivity deficits caused by burnup, and can also be used to implement rapid safe shutdowns. Compared to other control methods, the main drawback of solid control rod control is that the large absorption cross-section and high reactivity value of the neutron absorber material result in greater disturbances to the core power distribution and neutron flux density distribution. According to their function and purpose, control rods are generally classified into the following types: 1) Safety rods are mainly used for reactor start-up and shutdown control; 2) Compensation rods are mainly used to compensate for reactivity deficits caused by factors such as the accumulation of fission products and nuclear fuel burnup during reactor operation; 3) Regulation rods are mainly used for reactor power regulation. Currently, all metal-cooled fast neutron reactors in operation, under construction, and under research use control rods as the primary reactivity control method. Examples include the Russian sodium-cooled fast neutron reactors BOR-60, BN-600, BN-800, and BN-1200, the lead-cooled fast reactors BREST-300 and BREST-1200, the American sodium-cooled fast neutron reactors SEFOR, FFTF, and VTR, and the European Union lead-cooled fast neutron reactors ALFRED and MYRRHA.

[0004] Compared to light water-cooled thermal neutron reactors, the neutronics characteristics of lead-cooled fast neutron reactors impose higher safety requirements on control rod design to ensure redundancy in reactivity control and reactor criticality safety. This mainly includes the following two aspects: 1) At least two relatively independent control rod systems must be installed, each capable of reactor shutdown, and each system must meet the "sticking criterion"; 2) The depth of cold shutdown and the minimum subcriticality during refueling must be greater than the core's delayed neutron fraction. Therefore, it is essential to innovate reactivity control methods for lead-cooled fast neutron reactors and use them in conjunction with existing control rod systems to improve the reactivity control capability and criticality safety of lead-cooled fast neutron reactors. This is of great significance for the innovative development and engineering of lead-cooled fast neutron reactors. Summary of the Invention

[0005] This application aims to solve at least one of the technical problems in the background art by providing a safety component, a lead-cooled fast neutron reactor, and a passive negative reactive feedback method.

[0006] This application is achieved through the following technical solution:

[0007] In a first aspect, this application provides a security component, including:

[0008] First positioning component;

[0009] Second positioning component;

[0010] The container has a first positioning member and a second positioning member connected to it to position the container at both ends in a linear direction. The container has a cavity for containing coolant, and one end of the cavity in the longitudinal direction is connected to the outside of the container.

[0011] In some alternative embodiments, the receiving member has multiple flow holes to communicate the receiving cavity with the outside of the receiving member.

[0012] In some alternative implementations, the plurality of flow holes are circumferentially distributed.

[0013] In some alternative implementations, the extension directions of the plurality of flow holes are coplanar.

[0014] In some alternative implementations, the flow hole is a circular hole.

[0015] Secondly, this application provides a lead-cooled fast neutron reactor, comprising:

[0016] A reactor vessel, the reactor vessel being filled with coolant;

[0017] Fuel assemblies, several of which are located within the reactor vessel and immersed in the coolant;

[0018] Any of the safety components described in the first aspect, wherein a plurality of the safety components are arranged around a plurality of the fuel components, wherein the axial length of the receiving cavity of the safety component is greater than the axial length of the active region of the fuel component, and the active region of the fuel component is located within the axial length range of the receiving cavity.

[0019] In some alternative implementations, the axial length of the safety component is greater than the axial length of the fuel component.

[0020] In some alternative implementations, the external shape of the safety component is the same as that of the fuel component.

[0021] In some alternative embodiments, the fuel assembly has a square cross-sectional shape.

[0022] In some alternative embodiments, the fuel assembly has a regular hexagonal cross-sectional shape.

[0023] In some alternative implementations, the radial structural dimensions of the safety component are the same as those of the fuel component.

[0024] Thirdly, this application provides a passive negative reactive feedback method, implemented based on any of the lead-cooled fast neutron reactors described in the first aspect, wherein an inert gas is filled into the containment cavity before the reactor is put into operation.

[0025] Compared with the prior art, this application has the following advantages and beneficial effects:

[0026] The safety components, lead-cooled fast neutron reactor, and passive negative reactivity feedback method provided in this application, without altering the overall reactor structure or setting up additional auxiliary systems, only require a very simple and reliable safety component arranged on the outermost periphery of the core reflector. By fully utilizing the inherent neutron physical and chemical properties of lead coolant, in various accidents that cause a rapid rise in reactor coolant temperature, based on the fundamental principle of gas thermal expansion, the volume of lead coolant within the safety component is reduced, significantly increasing the core neutron leakage rate. This rapidly introduces negative reactivity into the core, reducing reactor operating power and coolant temperature, ensuring reactor safety. The process is very simple and reliable; any increase or decrease in the total amount of negative reactivity can be achieved simply by adjusting the loading of the reflector safety component, making implementation convenient. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the exemplary embodiments of this application, 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 this application and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0028] Figure 1 This is a schematic diagram of the security component structure provided in an embodiment of this application;

[0029] Figure 2 This is a schematic diagram of the lead-cooled fast neutron reactor structure provided in an embodiment of this application;

[0030] Figure 3 This is a schematic diagram of the internal partitioning of a lead-cooled fast neutron reactor provided in an embodiment of this application;

[0031] Figure 4 This is a schematic diagram of the structure of a lead-cooled fast neutron reactor under normal operation, provided in an embodiment of this application.

[0032] Figure 5 A schematic diagram of the structure of a lead-cooled fast neutron reactor when negative reactivity is introduced, as provided in an embodiment of this application;

[0033] Figure 6 A schematic diagram of the arrangement of fuel components and safety components provided in an embodiment of this application;

[0034] Figure 7 This is a schematic diagram of another arrangement of fuel components and safety components provided in an embodiment of this application.

[0035] The attached diagram shows the markings and corresponding component names:

[0036] 1-First positioning component, 2-Second positioning component, 3-Containing component, 4-Flow hole, 5-Containing cavity, 6-Reactor container, 7-Bed, 8-Fuel assembly, 9-Safety assembly, 10-Core active zone, 11-Core reflector zone. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this application are only for explaining this application and are not intended to limit this application.

[0038] The embodiments of this application aim to enrich the existing reactivity control methods for lead-cooled fast neutron reactors, fully utilize the physicochemical properties of high-temperature liquid lead coolant and the neutronics properties of lead-cooled fast neutron reactors, and propose a more efficient, simpler control mode with inherent safety characteristics. Without changing the overall structure of the lead-cooled fast neutron reactor, it organically integrates with existing reactivity control methods, enhances the overall reactivity control capability of the lead-cooled fast neutron reactor, strengthens the inherent safety characteristics of the lead-cooled fast neutron reactor, and improves engineering feasibility.

[0039] Example 1

[0040] like Figure 1 As shown, this application embodiment provides a safety component, which includes a first positioning member 1, a second positioning member 2, and a receiving member 3; the safety component is generally a strip structure.

[0041] The first positioning member 1 and the second positioning member 2 are respectively connected to the receiving member 3 to realize the positioning of the receiving member 3 at both ends in the linear direction. For example, in the working state, the length direction of the safety component is vertical. The first positioning member 1 and the second positioning member 2 are respectively used for positioning the upper and lower ends of the safety component to ensure the stability of the safety component in the working state. The first positioning member 1, the receiving member 3, and the second positioning member 2 can be formed into a whole by an integral molding process. The first positioning member 1 and the second positioning member 2 can also be connected to the receiving member 3 by, for example, welding. The receiving member 3 has a receiving cavity 5 for containing coolant. The receiving cavity 5 is a relatively closed cavity. The shape of the receiving cavity 5 can be set as cylindrical. One end of the receiving cavity 5 in the length direction is connected to the outside of the receiving member 3, that is, the gas phase or liquid phase outside the receiving member 3 can enter the receiving cavity 5.

[0042] The safety component provided in this application adopts a passive response mechanism based on physical principles, which does not rely on external power sources, mechanical drives, or operator intervention, resulting in fast response speed and high reliability. The positioning and containment functions are integrated into a single strip component, simplifying the complexity of the reactor core components and facilitating manufacturing, inspection, installation, and replacement. Integrated molding or reliable welding processes ensure the overall structural integrity and mechanical strength of the component, enabling it to withstand various loads during long-term operation. The containment cavity 5 is designed as a cylinder, conforming to the optimal stress distribution principle of pressure vessels and helping to withstand internal and external pressure differences. When applied to a nuclear reactor, through the synergistic effect of the strip structure design and internal components, it can automatically and rapidly introduce negative reactivity into the reactor core under preset or accident conditions, effectively and quickly suppressing or terminating the reactor nuclear fission chain reaction and preventing potential risks caused by power runaway. This safety component adopts a simple strip structure, consisting of a first positioning component 1, a containment component 3, and a second positioning component 2 connected sequentially. This not only makes the component structurally compact and robust but also facilitates modular arrangement and positioning installation within the reactor core. In the working state, the component is set vertically, and the first positioning part 1 and the second positioning part 2 at the upper and lower ends are firmly connected to the housing part 3 through reliable processes such as integral molding or welding. This ensures that the safety component can always maintain the predetermined posture and stability in the harsh working environment of high temperature, high radiation and fluid erosion, and avoids its safety function from being affected by vibration or deformation under force, thus providing a structural foundation for its long-term reliable operation. The relatively sealed cylindrical cavity inside the containment component 3 serves as containment chamber 5, which can be used to contain lead coolant. Before use, inert gas at a certain pressure needs to be filled into containment chamber 5. During normal power operation of the reactor, due to the balance of internal and external pressures, lead coolant enters containment chamber 5, increasing the thickness of the reflective layer of the safety component as a reflector, which can effectively suppress neutron leakage. When the reactor experiences an emergency such as a sudden increase in power or a rapid rise in coolant temperature, which requires the introduction of negative reactivity, the inert gas in containment chamber 5 expands due to heat, and the lead coolant in containment chamber 5 will be squeezed out of the safety component by the inert gas. The liquid level of lead coolant in containment chamber 5 drops, thereby reducing the reflective thickness of the safety component as a reflector, significantly increasing the core neutron leakage rate, rapidly introducing negative reactivity into the core, reducing reactor power and core coolant temperature, and achieving rapid power reduction or shutdown.

[0043] In some alternative embodiments, the receiving member 3 is provided with a plurality of flow holes 4 to connect the receiving cavity 5 to the outside of the receiving member 3.

[0044] In this embodiment, the number of flow holes 4 is at least two, so that the lead coolant can quickly enter the receiving cavity 5, thereby achieving the design standard of rapid introduction of negative reactivity. The shape of the flow holes 4 is not limited, and can be designed as square, round, elliptical, triangular, etc. Preferably, the shape of the flow holes 4 is designed as round holes. On the one hand, it is easy to process and manufacture, and the round hole has high impact resistance, which can cope with the working environment of rapid flow of lead coolant into the receiving cavity 5. On the other hand, the smooth inner wall has little impact on the flow of lead coolant and basically does not produce a blocking effect, which is conducive to improving the introduction speed of negative reactivity. In actual implementation, the overall shape of the receiving component 3 is cylindrical, and the extension direction of each flow hole 4 is along the radial direction of the receiving component 3. That is, when the flow hole 4 is designed as a round hole, the axial direction of the flow hole 4 coincides with the radial direction of the receiving component 3.

[0045] The multiple flow holes 4 are evenly distributed around the axial circumference of the receiving member 3, which will help increase the rate at which lead coolant enters the receiving cavity 5.

[0046] In some optional embodiments, the extension directions of the plurality of flow holes 4 are coplanar. That is, in the axial direction of the receiving member 3, the distance between each flow hole 4 and the end of the receiving member 3 is equal. The purpose of this design is to enable the lead coolant in each flow hole 4 to achieve a counter-current effect, and the lead coolant in each flow hole 4 to a certain extent inhibits the flow rate of each other, preventing the cavity wall of the receiving cavity 5 from being subjected to large impacts. This will help ensure the stability of the safety component in the working state.

[0047] Example 2

[0048] Please refer to them together. Figure 2 and Figure 3This application provides a lead-cooled fast neutron reactor, which includes a reactor vessel 6, fuel assemblies 8, and any of the safety components 9 described in Embodiment 1. The overall shape of the reactor vessel 6 is not limited, and can be, for example, a square vessel, a cylindrical vessel, a triangular vessel, or other polygonal prism vessels. In this embodiment, the reactor vessel 6 is designed as a cylindrical vessel with a spherical bottom. The reactor vessel 6 is filled with a coolant, which in this embodiment is a lead coolant. A basket 7 is installed inside the reactor vessel 6, and several fuel assemblies 8 are fixedly connected to the basket 7. The length of the fuel assemblies 8 is perpendicular to the depth of the reactor vessel 6. The coolant level in the reactor vessel 6 is configured such that the fuel assembly 8 is completely submerged in the coolant. In operation, the upper end of the fuel assembly 8 is a certain distance from the surface of the coolant. Multiple safety components 9 are arranged around the fuel assemblies 8, meaning that multiple safety components 9 are located on the periphery of all fuel assemblies 8. The axial length of the receiving cavity 5 of the safety component 9 is greater than the axial length of the active area of ​​the fuel assembly 8, and the active area of ​​the fuel assembly 8 is located within the axial length of the receiving cavity 5. This means that from the radial perspective of the receiving member 3, the two ends of the active area of ​​the fuel assembly 8 are respectively spaced from the two ends of the receiving cavity 5.

[0049] The lead-cooled fast neutron reactor provided in this application embodiment utilizes the thermal energy generated by the accident itself as a driving source. Through the inert gas pre-placed in the containment cavity 5 of the safety component 9, the temperature signal is directly converted into mechanical action, thereby altering the physical state of the reactor core and rapidly introducing negative reactivity. Specifically, during normal reactor operation, the containment cavity 5 of the safety component 9 constitutes a pressure balance system: the lower part is filled with liquid lead coolant, while the upper part contains inert gas at a predetermined pressure and volume. At this time, the lead in the containment cavity 5 acts as a highly efficient neutron scatterer, forming an effective neutron reflector layer together with other structures around the reactor core. This scatters a large number of fast neutrons attempting radial leakage back into the active region 10 of the reactor core, which helps maintain the high neutron economy and criticality of the reactor core. In the event of an emergency such as loss of cooling or a sudden increase in power that causes an overall temperature rise, the increased temperature of the lead coolant inside the reactor will heat the walls of the containment component 3 of the safety assembly 9 through thermal conduction. This, in turn, will heat the inert gas in the containment cavity 5. Under constant volume conditions, the gas pressure is proportional to the thermodynamic temperature; therefore, the pressure of the inert gas in the containment cavity 5 will increase significantly with the temperature rise. When this pressure rises to a certain value, the inert gas will act as a pneumatic piston, forcibly squeezing out the liquid lead at the bottom of the containment cavity 5 through the bottom connecting hole and discharging it into the reactor vessel 6. This will cause the lead level in the containment cavity 5 to continuously decrease, and the space originally occupied by lead will be replaced by the expanding inert gas. As a result, the effective thickness of the neutron reflector surrounding the fuel assembly 8 will be significantly reduced, directly leading to a sharp decrease in the neutron reflectivity at the core edge. This makes it easier for fast neutrons, which were originally confined within the core, to leak radially, thereby introducing negative reactive feedback, automatically and rapidly suppressing or terminating the nuclear fission chain reaction, and achieving a safe shutdown.

[0050] The lead-cooled fast neutron reactor provided in this application embodiment achieves purely passive safety. The entire triggering and operation process is governed entirely by physical laws (such as thermodynamics, gas laws, and neutron physics), without relying on external power sources, pumps, sensors, or operator judgment and intervention, fundamentally eliminating the risk of active system failure. Secondly, the temperature rise caused by the accident itself is a direct driving signal, and the increase in inert gas pressure and the discharge of liquid lead is a rapid physical process with a response speed faster than traditional control rod systems that require mechanical transmission and insertion stroke, enabling it to play a role in the early stages of accident development. Furthermore, this lead-cooled fast neutron reactor does not have complex mechanical moving parts (such as motors, gears, connecting rods, etc.), reducing potential failure points; the inert gas and lead coolant it relies on are both existing media within the reactor or have extremely stable chemical properties, resulting in a simple system structure that is easy to manufacture and maintain. Finally, by arranging multiple safety components 9 around the core and ensuring that the axial length of the containment cavity 5 covers the entire fuel active area, a comprehensive and blind-spot-free passive safety barrier is formed. No matter where the accident originates in the core, the resulting overall temperature rise will synchronously trigger all these safety components 9, ensuring that negative reactivity is introduced uniformly and reliably.

[0051] The lead-cooled fast neutron reactor provided in this application embodiment can re-establish dynamic pressure balance inside and outside the safety component 9 after the reactor cools down, and the thickness of the reflector layer can recover on its own. After the fault is cleared and the reactor is restarted, there is no need to repeat the operation of the safety component 9.

[0052] The following detailed description, in conjunction with the accompanying drawings, will help to understand the working principle of the embodiments of this application:

[0053] like Figure 2 , Figure 3 As shown, different types of fuel assemblies 8 are arranged in the core active zone 10, and safety assemblies 9 are arranged on the outermost periphery of the core reflector zone 11. Because the density of lead coolant changes very little with temperature, the lead coolant level in the reactor vessel 6 remains essentially constant. Before the safety assembly 9 is installed in the core, it is pre-filled with an inert gas at a certain pressure to ensure that after the lead coolant enters the internal space of the safety assembly 9, the liquid level reaches a predetermined position, slightly higher than the core active zone 10. The pressure in the gas chamber inside the safety assembly 9 is the pressure difference formed by the difference between the lead coolant liquid level inside the reactor vessel 6 and the lead coolant liquid level inside the safety assembly 9.

[0054] like Figure 4As shown, as the reactor starts up and the reactor power increases, the core coolant temperature gradually rises, and the inert gas temperature and pressure in the safety assembly 9 also rise accordingly. Since the external pressure remains unchanged, some of the lead coolant in the safety assembly 9 is discharged until the pressure in the safety assembly 9 containment cavity 5 reaches equilibrium with the external pressure, and the lead coolant liquid level in the safety assembly 9 containment cavity 5 is basically level with the height of the core active zone 10.

[0055] like Figure 5 As shown, if any accident occurs that causes a rapid rise in the core coolant temperature, the temperature and pressure of the inert gas inside safety assembly 9 will also rise rapidly. Since the density of lead coolant changes little with temperature, the lead coolant level inside reactor vessel 6 remains essentially constant, meaning the external pressure of safety assembly 9 remains unchanged. The inert gas pre-installed inside safety assembly 9 expands rapidly, expelling more lead coolant from safety assembly 9. The lead coolant level will be significantly lower than the height of the core active zone 10, solely due to the expansion of the inert gas. This will rapidly reduce the thickness of the core's outer reflector layer, significantly increase the core neutron leakage rate, and quickly introduce negative reactivity into the core, reducing reactor power and core coolant temperature.

[0056] In this embodiment, the inert gas pre-filled in the receiving cavity 5 of the safety component 9 can be helium or argon.

[0057] In some alternative embodiments, the axial length of the safety component 9 is greater than the axial length of the fuel assembly 8; specifically, the axial length of the safety component 9 is configured such that the axial length of the receiving cavity 5 is not less than the length of the middle portion of the fuel assembly 8.

[0058] Example 3

[0059] Please refer to them together. Figure 2 and Figure 6This application provides a lead-cooled fast neutron reactor, which includes a reactor vessel 6, fuel assemblies 8, and any of the safety components 9 described in Embodiment 1. The overall shape of the reactor vessel 6 is not limited, and can be, for example, a square vessel, a cylindrical vessel, a triangular vessel, or other polygonal prism vessels. In this embodiment, the reactor vessel 6 is designed as a cylindrical vessel with a spherical bottom. The reactor vessel 6 is filled with a coolant, which in this embodiment is a lead coolant. A basket 7 is installed inside the reactor vessel 6, and several fuel assemblies 8 are fixedly connected to the basket 7. The cross-sectional shape of each fuel assembly 8 is square, meaning that each fuel assembly 8 has four smooth rectangular outer walls. The rectangular outer walls of adjacent fuel assemblies 8 correspond to each other. All fuel assemblies 8 are arranged in an array along the longitudinal and transverse directions, and the length direction of the fuel assemblies 8 is parallel to the depth direction of the reactor vessel 6. The coolant level is configured so that the fuel assembly 8 is completely submerged in the coolant. In operation, the upper end of the fuel assembly 8 is a certain distance from the coolant surface. Multiple safety components 9 are arranged around the fuel assemblies 8, meaning that multiple safety components 9 are located on the periphery of all fuel assemblies 8. The cross-sectional shape of the safety components 9 is the same as that of the fuel assembly 8, which is square. For the outermost fuel assembly 8, safety components 9 are arranged adjacent to each other along its diagonal direction, meaning that there are at least two safety components 9 at each end of any radial direction of any fuel assembly 8 to form a comprehensive neutron reflector barrier. The axial length of the receiving cavity 5 of the safety component 9 is greater than the axial length of the active region of the fuel assembly 8, and the active region of the fuel assembly 8 is located within the axial length of the receiving cavity 5. That is, from the radial perspective of the receiving member 3, the two ends of the active region of the fuel assembly 8 are spaced apart from the two ends of the receiving cavity 5.

[0060] Example 4

[0061] Please refer to them together. Figure 2 and Figure 7This application provides a lead-cooled fast neutron reactor, which includes a reactor vessel 6, fuel assemblies 8, and any of the safety components 9 described in Embodiment 1. The overall shape of the reactor vessel 6 is not limited, and can be, for example, a square vessel, a cylindrical vessel, a triangular vessel, or other polygonal prism vessels. In this embodiment, the reactor vessel 6 is designed as a cylindrical vessel with a spherical bottom. The reactor vessel 6 is filled with a coolant, which in this embodiment is a lead coolant. A basket 7 is installed inside the reactor vessel 6, and several fuel assemblies 8 are fixedly connected to the basket 7. The cross-sectional shape of each fuel assembly 8 is a regular hexagon, meaning that each fuel assembly 8 has six smooth rectangular outer walls. The fuel assemblies 8 can be arranged in an N-row configuration, with fuel assemblies 8 in adjacent rows alternating, meaning that a certain fuel assembly 8 in the N+1th row is located in a certain position within the N rows. At the very center of the two fuel assemblies 8, all fuel assemblies 8 are arranged in a honeycomb pattern. The length direction of the fuel assemblies 8 is parallel to the depth direction of the reactor vessel 6. The coolant level in the reactor vessel 6 is configured such that all fuel assemblies 8 are completely submerged in the coolant. In operation, the upper end of each fuel assembly 8 is a certain distance from the surface of the coolant. Multiple safety components 9 are arranged around several fuel assemblies 8, meaning that multiple safety components 9 are located on the periphery of all fuel assemblies 8. The cross-sectional shape of the safety components 9 is the same as that of the fuel assemblies 8, which is a regular hexagon. The axial length of the receiving cavity 5 of the safety component 9 is greater than the axial length of the active area of ​​the fuel assembly 8, and the active area of ​​the fuel assembly 8 is located within the axial length of the receiving cavity 5. That is, from the radial perspective of the receiving member 3, the two ends of the active area of ​​the fuel assembly 8 are spaced apart from the two ends of the receiving cavity 5.

[0062] Example 5

[0063] This application provides a passive negative reactive feedback method based on any of the lead-cooled fast neutron reactors described in Examples 2 to 4. Before the reactor is put into operation, inert gas is filled into the containment cavity 5.

[0064] In actual implementation, after the safety component 9 is manufactured, the flow hole 4 is sealed. For example, a specific metal film (such as nickel or stainless steel foil) can be connected to the substrate of the container 3 by welding, brazing, or deposition technology to block the flow hole 4. A vent hole is drilled at the end of the safety component 9 away from the flow hole 4. The container cavity 5 of the safety component 9 is evacuated, and then inert gas is injected into the container cavity 5 through the vent hole in a vacuum environment to seal the vent hole. The safety component 9 is placed in the lead coolant in the reactor vessel 6. As the sinking depth of the safety component 9 increases, the lead coolant will generate a large hydraulic pressure on the metal film. After the sinking depth of the safety component 9 reaches the preset value, the inert gas in the container cavity 5 and the lead coolant outside the container cavity 5 will generate the expected pressure difference. The lead coolant will break through the metal film and enter the container cavity 5, and the inert gas in the container cavity 5 will be squeezed to the upper part of the container cavity 5 by the lead coolant. The purpose of this implementation is to avoid underwater operation. For the treatment of metal films, regular fracture lines can be pre-created on the metal film by laser marking, chemical etching or mechanical indentation, so that the shape of the metal film after being broken is as expected. For example, after the metal film is broken, it is a petal-shaped structure with one end connected to the inner wall of the flow hole 4. The petal-shaped structure is tightly pressed against the inner wall of the flow hole 4 to avoid obstructing the lead coolant.

[0065] The specific embodiments described above illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Although the description of this application is presented in conjunction with some embodiments, this does not mean that the features of this application are limited to this embodiment. On the contrary, the purpose of describing the application in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of this application. To provide a thorough understanding of this application, many specific details are included in the above description. This application may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of this application, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0066] It should be noted that in this specification, similar reference numerals and letters in the above figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this application, it should be noted that unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" 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 mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0067] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A security component, characterized in that, include: First positioning component (1); Second positioning component (2); The container (3) is connected to the first positioning member (1) and the second positioning member (2) respectively to realize the positioning of the container (3) at both ends in the linear direction. The container (3) has a container cavity (5) for containing coolant. One end of the container cavity (5) in the length direction is connected to the outside of the container (3).

2. The security component according to claim 1, characterized in that, The receiving member (3) has multiple flow holes (4) to connect the receiving cavity (5) with the outside of the receiving member (3).

3. The security component according to claim 2, characterized in that, The multiple flow holes (4) are evenly distributed in a circle.

4. The security component according to claim 3, characterized in that, The extension directions of the plurality of flow holes (4) are coplanar.

5. The security component according to claim 2, characterized in that, The flow hole (4) is a round hole.

6. A lead-cooled fast neutron reactor, characterized in that, include: A reactor vessel (6) is filled with coolant; Fuel assemblies (8), a plurality of said fuel assemblies (8) are located within said reactor vessel (6) and immersed in said coolant; According to any one of claims 1 to 5, a plurality of the safety components (9) are arranged around a plurality of the fuel components (8), wherein the axial length of the receiving cavity (5) of the safety component (9) is greater than the axial length of the active region of the fuel component (8), and the active region of the fuel component (8) is located within the axial length range of the receiving cavity (5).

7. The lead-cooled fast neutron reactor according to claim 6, characterized in that, The axial length of the safety component (9) is greater than the axial length of the fuel component (8).

8. The lead-cooled fast neutron reactor according to claim 6, characterized in that, The external shape of the safety component (9) is the same as that of the fuel component (8).

9. The lead-cooled fast neutron reactor according to claim 8, characterized in that, The fuel assembly (8) has a square cross-sectional shape.

10. The lead-cooled fast neutron reactor according to claim 8, characterized in that, The fuel assembly (8) has a regular hexagonal cross-sectional shape.

11. The lead-cooled fast neutron reactor according to claim 8, characterized in that, The radial structural dimensions of the safety component (9) are the same as those of the fuel component (8).

12. A passive negative reactive feedback method, implemented based on a lead-cooled fast neutron reactor as described in any one of claims 6 to 11, characterized in that, Before the reactor is put into operation, inert gas is filled into the containment chamber (5).

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