Lead-cooled nuclear reactor with steam generator rupture accident mitigation technology

Abstract

The invention provides a lead-cooled nuclear reactor with a steam generator rupture accident mitigation technology, and relates to the technical field of nuclear power. The lead-cooled nuclear reactor comprises a reactor container provided with a reactor core, a steam generator and a flow guide assembly, the flow guide assembly is provided with a flow guide cavity with an open top end opening, the lower section of the steam generator extends into the flow guide cavity through the top end opening, the flow guide assembly comprises a vertical baffle, a bottom flow guide plate and a vertical flow guide plate, and the vertical baffle is located between the steam generator and the reactor core and provided with a liquid inlet; the bottom guide plate is located below the steam generator, and a first guide channel is formed between the bottom guide plate and the steam generator. The vertical guide plate is positioned on one side of the steam generator deviating from the reactor core, a second guide channel is formed between the vertical guide plate and the steam generator, a liquid outlet is formed above the vertical guide plate, and a third guide channel is formed between the vertical guide plate and the side wall of the reactor container. The flow guide assembly in the lead-cooled nuclear reactor is simple in structure, low in cost, small in flow resistance and capable of effectively degassing a coolant and ensuring the arrangement convenience of a steam generator.

Description

Technical Field

[0001] The present invention relates to the field of nuclear power technology, and particularly to a lead-cooled nuclear reactor with a steam generator rupture accident mitigation technology. Background Art

[0002] A lead-cooled fast reactor is a fast neutron reactor that uses liquid metal lead or lead-bismuth alloy as a coolant, and has good inherent safety, thermohydraulic, and neutron physics characteristics. It can be used for nuclear fuel breeding and long-lived fission product transmutation, and is of great significance for the sustainable development of nuclear energy.

[0003] The frequently occurring steam generator tube rupture (SGTR) accident (also known as the lead-water reaction accident) is considered to be one of the key problems restricting the development of lead-cooled fast reactors. Among them, the bubbles caused by the steam generator tube rupture accident follow the liquid metal into the core and cause core power fluctuations or even core melting. The conventional degassing structure has a weak degassing effect on liquid metal, and the degassing structure is complex, costly, has a large flow resistance, and will increase the layout difficulty of the steam generator, and is not suitable for deployment in lead-cooled fast reactors. Summary of the Invention

[0004] The purpose of the present invention is to provide a lead-cooled nuclear reactor with a steam generator rupture accident mitigation technology to solve the technical problems that the existing degassing structure has a weak degassing effect on liquid metal, and the degassing structure is complex, costly, has a large flow resistance, and will increase the layout difficulty of the steam generator.

[0005] To solve the above problems, the present invention provides a lead-cooled nuclear reactor with a steam generator rupture accident mitigation technology, including a reactor vessel with a coolant accommodated in a lower region, a core, a steam generator, and a diversion assembly disposed in the reactor vessel. The diversion assembly has a diversion cavity with an open top port, and a lower section of the steam generator extends into the diversion cavity through the top port. Among them, the diversion assembly includes: A vertical baffle located between the steam generator and the core, with a top end higher than the coolant, and provided with an inlet for the coolant to flow into the steam generator; A bottom diversion plate located below the steam generator and forming a first diversion channel for the coolant to flow between the bottom diversion plate and the steam generator; and, A vertical diversion plate located on a side of the steam generator away from the core. A second diversion channel for the coolant to flow upward is formed between the vertical diversion plate and the steam generator, an outlet for the coolant to flow out is formed above, and a third diversion channel for the coolant to flow downward is formed between the vertical diversion plate and the side wall of the reactor vessel.

[0006] Optionally, the diversion cavity is annular and disposed around the outer periphery of the reactor core; there are a plurality of steam generators, and the plurality of steam generators are circumferentially disposed around the outer periphery of the reactor core, and the lower sections of the plurality of steam generators all extend into the diversion cavity through the top ports.

[0007] Optionally, the second diversion channel is provided with a flow disturbing member, and the flow disturbing member can disturb the coolant flowing through it.

[0008] Optionally, the flow disturbing member includes spiral guide vanes extending spirally upward from bottom to top.

[0009] Optionally, the spiral guide vanes are located in the area where the second diversion channel intersects the first diversion channel.

[0010] Optionally, a horizontal flow retarder plate is connected to the top end of the vertical guide plate. There are openings for the coolant to flow between the horizontal flow retarder plate and both the steam generator and the reactor vessel, and the plate area of the horizontal flow retarder plate gradually increases in the direction away from the reactor core.

[0011] Optionally, in the direction away from the steam generator, the horizontal flow retarder plate includes a first flow retarder plate area and a second flow retarder plate area. Among them, the first flow retarder plate area is located on the side of the vertical guide plate facing the steam generator, and the second flow retarder plate area is located on the side of the vertical guide plate facing away from the steam generator.

[0012] Optionally, a bubble collection structure is provided above the horizontal flow retarder plate, and the bubble collection structure is used to collect the bubbles in the coolant flowing through the corresponding area.

[0013] Optionally, the bubble collection structure includes a plurality of collecting vertical rods arranged in parallel. The collecting vertical rods are made of a material that is sparse in coolant and hydrophilic to bubbles, and the bottom end of the collecting vertical rod extends downward into the coolant, and the top end extends upward out of the coolant.

[0014] Optionally, the flow velocity range of the coolant flowing through the steam generator is 0.1 m / s to 0.25 m / s.

[0015] In the lead-cooled nuclear reactor provided by the present invention, the arrangement of the flow guiding assembly, on the one hand, can form a first flow guiding channel, a second flow guiding channel and a third flow guiding channel for guiding the coolant. Among them, the first flow guiding channel can guide the coolant with entrained bubbles away from the reactor core to reduce the entry of bubbles into the reactor core; the second flow guiding channel can guide the coolant with entrained bubbles to move upward, so that the bubbles can more easily move upward and break away from the coolant and enter the gas cavity. The third flow guiding channel increases the flow stroke of the coolant, so that the bubbles with upward movement speed entrained by it can continue to move upward and break away from the coolant and enter the gas cavity, thereby realizing effective degassing treatment of the coolant and reducing the occurrence of reactor core power fluctuations or even meltdown accidents caused by bubbles entering the reactor core; on the other hand, the flow guiding assembly only includes a bottom flow guiding plate extending approximately horizontally and vertical baffles and vertical flow guiding plates extending vertically. The structure is simple, the cost is low, the flow resistance is small, the driving load requirement for the driving pump is correspondingly low, the maintenance requirement is low, and the safety is relatively high; at the same time, both the vertical baffle and the vertical flow guiding plate of the flow guiding assembly are vertical plate bodies, and the lower section of the steam generator can extend downward into the flow guiding cavity through the open top port at the top of the flow guiding assembly, that is, the arrangement of the flow guiding assembly has no influence on the original installation arrangement of the steam generator, thereby ensuring the convenience of the installation arrangement of the steam generator. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 It is a front internal view of the lead-cooled nuclear reactor with a steam generator rupture accident mitigation technology provided by the embodiment of the present invention in the first form; Figure 2 It is a front internal view of the lead-cooled nuclear reactor with a steam generator rupture accident mitigation technology provided by the embodiment of the present invention in the second form; Figure 3 It is a top internal view of the lead-cooled nuclear reactor with a steam generator rupture accident mitigation technology provided by the embodiment of the present invention in the second form; Figure 4 is Figure 3 a schematic diagram of the lead-cooled nuclear reactor after removing the horizontal flow retarder and the bubble collection structure.

[0018] Description of the reference numerals: 100 - Heap container; 110 - Gas cavity; 120 - Molten pool; 200 - Coolant; 300 - Reactor core; 400 - Steam generator; 500 - Flow - guiding assembly; 50A - Flow - guiding cavity; 510 - Top port; 520 - Vertical baffle; 521 - Liquid inlet; 530 - Bottom flow - guiding plate; 53A - First flow - guiding channel; 540 - Vertical flow - guiding plate; 54A - Second flow - guiding channel; 54B - Third flow - guiding channel; 600 - Turbulence - generating part; 700 - Horizontal flow - damping plate; 710 - First flow - damping plate area; 720 - Second flow - damping plate area; 70A - Opening; 70B - Horizontal flow - damping area; 800 - Bubble collection structure; 810 - Collection vertical rod. Detailed implementation manners

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0021] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0022] This embodiment provides a lead - cooled nuclear reactor with a steam generator rupture accident mitigation technology, as Figure 1 and Figure 2As shown, the stack container 100 includes a lower region containing a coolant 200, the stack container 100 is provided with a core 300, a steam generator 400 and a flow guide assembly 500, the flow guide assembly 500 has a flow guide cavity 50A with a top port 510 opened, the heat transfer pipe of the lower section of the steam generator 400 extends into the flow guide cavity 50A through the top port 510, wherein the flow guide assembly 500 includes a vertical baffle 520, a bottom flow guide plate 530 and a vertical flow guide plate 540, wherein the vertical baffle 520 is located between the steam generator 400 and the stack core 300, the top of the vertical baffle 520 is higher than the coolant 200, and is provided with a guide hole for the coolant 200 to flow into the steam generator. The bottom guide plate 530 is located below the steam generator 400, and forms a first guide channel 53A with the steam generator 400 for the coolant 200 to flow; the vertical guide plate 540 is located on the side of the steam generator 400 away from the core 300, and forms a second guide channel 54A with the steam generator 400 for the coolant 200 to flow upward, the upper part of the vertical guide plate 540 is lower than the coolant 200 to form a liquid outlet for the coolant 200 to flow out, and a third guide channel 54B for the coolant 200 to flow downward is formed between the vertical guide plate 540 and the side wall of the stack container 100.

[0023] In the lead-cooled nuclear reactor provided in this embodiment, Figure 1 and Figure 2As shown, the internal space of the reactor vessel 100 is divided into an upper area and a lower area in the vertical direction, and is divided into a middle area and an outer ring area surrounding the middle area in the radial direction, wherein the lower area is used as a molten pool 120 to accommodate the coolant 200, and the upper area is used as an air cavity 110; the core 300 is located in the middle area of ​​the reactor vessel 100 and immersed in the coolant 200, the steam generator 400 is located in the outer ring area of ​​the reactor vessel 100, and the lower heat exchange section of the steam generator 400 extends downward into the coolant 200; the guide assembly 500 as a degassing structure is box-shaped, and includes a box bottom plate and a box side plate arranged at the edge of the box bottom plate and extending vertically upward, the lower section of the steam generator 400 extends into the guide cavity 50A through the top top port 510 thereof, and in the guide assembly 500, the steam generator 400 and the core 300 are located at the top of the guide cavity 50A. The box side plate between the vertical baffles 520 serves as a vertical baffle 520, and the vertical baffle 520 extends vertically upward to above the liquid level of the coolant 200; the box side plate located on the side of the steam generator 400 away from the core 300 serves as a vertical guide plate 540, the vertical guide plate 540 extends vertically and its top is lower than the liquid level of the coolant 200, and at the same time, the vertical guide plate 540 is spaced apart from the side walls of the steam generator 400 and the stack container 100 to form a second guide channel 54A with the steam generator 400 and a third guide channel 54B with the side walls of the stack container 100 respectively; the box bottom plate is connected between the bottom ends of the vertical baffles 520 and the vertical guide plates 540, the box bottom plate serves as a bottom guide plate 530 and is located below the steam generator 400, and the box bottom plate is spaced apart from the steam generator 400 to form a first guide channel 53A.

[0024] When using, Figure 1As shown by the dashed arrow in the figure, the coolant 200 flows upward through the core 300 from bottom to top under the driving action to exchange heat with it. The coolant 200 that absorbs heat flows out of the core 300 upward and flows into the steam generator 400 through the liquid inlet 521 on the vertical baffle 520. Subsequently, the coolant 200 flows downward through the steam generator 400 to transfer heat to the working fluid in the steam generator 400. After transferring heat, the coolant 200 flows downward from the lower end of the steam generator 400 into the flow guiding assembly 500, and then flows away from the core 300 along the first flow guiding channel 53A under the guiding action of the bottom flow guiding plate 530. When the coolant 200 flows to the end of the first flow guiding channel 53A, it then flows upward along the second flow guiding channel 54A under the guiding action of the vertical flow guiding plate 540. Continuing, when the coolant 200 flows upward to the top of the second flow guiding channel 54A, it turns and flows through the liquid outlet formed above the vertical flow guiding plate 540 into the third flow guiding channel 54B, and then flows downward along the third flow guiding channel 54B under the combined guiding action of the vertical flow guiding plate 540 and the side wall of the reactor vessel 100. Subsequently, the coolant 200 flows downward past the lower part of the flow guiding assembly 500 and reaches the bottom of the core 300, and then flows upward into the core 300 again to achieve cyclic heat exchange.

[0025] When a rupture accident occurs in the heat transfer tubes in the lower section of the steam generator 400, causing bubbles to enter the coolant 200, the smaller bubbles are subject to a smaller buoyancy force and a larger drag force from the coolant 200, so they flow with the coolant 200. Specifically, the bubbles first move away from the core 300 along the first flow guiding channel 53A with the coolant 200 to reduce the entry of bubbles into the core 300. Subsequently, the bubbles enter the second flow guiding channel 54A with the coolant 200 and flow upward. During this process, the bubbles are simultaneously subject to the upward buoyancy force and drag force of the coolant 200, which makes it easier for the bubbles to move upward and break away from the coolant 200 and enter the gas cavity 110. Continuing, for the bubbles that have not broken away from the coolant 200 in the second flow guiding channel 54A, at the initial stage when they enter the third flow guiding channel 54B with the coolant 200 and flow downward along it, the bubbles still have an upward movement speed and continue to move upward to break away from the coolant 200 and enter the gas cavity 110, thereby achieving effective degassing treatment of the coolant 200 and reducing the occurrence of accidents such as power fluctuations or even meltdown in the core 300 caused by bubbles entering the core 300.

[0026] In the lead-cooled nuclear reactor provided by this embodiment, the arrangement of the flow guiding assembly 500 can, on the one hand, form a first flow guiding channel 53A, a second flow guiding channel 54A and a third flow guiding channel 54B for guiding the coolant 200. Among them, the first flow guiding channel 53A can guide the coolant 200 with entrained bubbles away from the reactor core 300 to reduce the entry of bubbles into the reactor core 300; the second flow guiding channel 54A can guide the coolant 200 with entrained bubbles to move upward, so that the bubbles can move upward more easily and break away from the coolant 200 and enter the gas cavity 110. The third flow guiding channel 54B increases the flow travel of the coolant 200, so that the bubbles with an upward movement speed entrained therein can continue to move upward and break away from the coolant 200 and enter the gas cavity 110, thereby realizing effective degassing treatment of the coolant 200 and reducing the occurrence of power fluctuations or even meltdown accidents in the reactor core 300 caused by bubbles entering the reactor core 300. On the other hand, the flow guiding assembly 500 only includes a bottom flow guiding plate 530 extending approximately horizontally, a vertical baffle 520 and a vertical flow guiding plate 540 extending vertically. The structure is simple, the cost is low, the flow resistance is small, the driving load requirement for the driving pump is correspondingly low, the maintenance requirement is low, and the safety is relatively high. At the same time, both the vertical baffle 520 and the vertical flow guiding plate 540 of the flow guiding assembly 500 are vertical plates, and the lower section of the steam generator 400 can extend downward into the flow guiding cavity 50A through the open top port 510 at the top of the flow guiding assembly 500, that is, the arrangement of the flow guiding assembly 500 has no influence on the original installation arrangement of the steam generator 400, thus ensuring the convenience of the installation arrangement of the steam generator 400.

[0027] Specifically, the coolant 200 of the lead-cooled nuclear reactor can adopt liquid metal lead or lead-bismuth alloy.

[0028] In this embodiment, as Figures 2 - 4As shown, the diversion cavity 50A is annular and is disposed around the outer periphery of the reactor core 300; there are multiple steam generators 400, and the multiple steam generators 400 are disposed around the outer periphery of the reactor core 300 in the circumferential direction, and the lower segments of the multiple steam generators 400 extend into the diversion cavity 50A through the top ports 510. The multiple steam generators 400 are arranged at intervals in the circumferential direction of the outer ring area in the reactor vessel 100 to improve the heat exchange effect with the coolant 200; the diversion assembly 500 is arranged in the shape of an annular box. Specifically, the diversion assembly 500 includes an annular box bottom plate and two annular box side plates. The box bottom plate serves as the bottom diversion plate 530 and is located below the multiple steam generators 400 at the same time, so as to form a first diversion channel 53A between each steam generator 400; one of the box side plates is correspondingly connected to the inner ring edge of the box bottom plate and extends vertically upward, and this box side plate serves as the vertical baffle 520 and can simultaneously block between the reactor core 300 and the multiple steam generators 400; the other box side plate is correspondingly connected to the outer ring edge of the box bottom plate and extends vertically upward, and this box side plate serves as the vertical diversion plate 540 and is disposed around the side wall of the reactor vessel 100 and the multiple steam generators 400, so as to form a second diversion channel 54A between each steam generator 400, and at the same time form a third diversion channel 54B corresponding to the multiple steam generators 400 between the side wall of the reactor vessel 100.

[0029] In this embodiment, by setting the diversion assembly 500 as a simple-structured annular member, the diversion and degassing functions of the coolant 200 output by the multiple steam generators 400 can be realized simultaneously, thereby further improving the structural simplicity and layout convenience of the degassing structure, and reducing the cost and resistance of the degassing structure; in addition, the annular diversion assembly 500 divides the hot and cold regions of the molten pool 120 into two different regions, and can also effectively reduce the thermal stratification effect of the lead-cooled nuclear reactor, making it have strong engineering applicability.

[0030] Among them, Figures 2 - 4 the number of the steam generators 400 in is shown as 8 for illustration, and it is not a limitation.

[0031] Of course, in some other embodiments, there can also be multiple diversion assemblies 500, and the multiple diversion assemblies 500 are arranged corresponding to the multiple steam generators 400 one by one, and a side connection plate can also be connected between the side edges of the vertical baffle 520 and the vertical diversion plate 540 of the diversion assembly 500, so that the side walls of each diversion assembly 500 are in a closed state, thereby ensuring that the coolant flowing into the diversion cavity 50A can flow along the first diversion channel and the second diversion channel, and reducing the occurrence of the coolant flowing out from the gap between the vertical baffle 520 and the vertical diversion plate 540.

[0032] In this embodiment, as Figures 1 - 4As shown, a spoiler 600 is provided in the second diversion channel 54A, and the spoiler 600 can disrupt the flow of the coolant 200 passing through it. When the coolant 200 carrying bubbles flows upward along the second diversion channel 54A and passes through the spoiler 600, the spoiler 600 can disrupt the flow of the coolant 200, so as to intensify the collision and coalescence between the bubbles in the coolant 200. Correspondingly, the mutually colliding bubbles can merge into larger bubbles, so that the buoyancy force received by the bubbles increases, and thus it is easier to move upward and break away from the coolant 200 and enter the gas cavity 110, thereby further improving the degassing effect on the coolant 200 and further reducing the adverse effects caused by the bubbles entering the core 300.

[0033] Specifically, in this embodiment, the spoiler 600 includes spiral guide vanes extending spirally upward from bottom to top. When the coolant 200 carrying bubbles enters the second diversion channel 54A and flows upward through the spiral guide vanes, it can flow upward in a spiral shape under the guiding action of the spiral guide vanes. Due to the large density difference between the coolant 200 and the bubbles, during the process of the coolant 200 carrying bubbles flowing upward in a spiral shape, it will cause the bubbles to gather towards the center of rotation of the spiral fluid, thereby enhancing the collision and coalescence between the bubbles; at the same time, in the rotating flow field, the pressure distribution is mainly determined by the centrifugal force, and the centrifugal force is outward, so the pressure increases from the center of rotation outward accordingly, that is, the pressure at the center of rotation is lower, and the bubbles located at the center of rotation expand and are more likely to merge, so that the mutually colliding bubbles can merge into larger bubbles, the buoyancy force received by the large bubbles increases, the upward movement speed is faster, and it is easier to break away from the coolant 200 upward and enter the gas cavity 110, thereby further improving the degassing effect of the degassing structure on the coolant 200. Moreover, the spiral guide vane structure is simple, the installation convenience is high, and the flow resistance to the coolant 200 is small.

[0034] Among them, during the process of the bubbles flowing upward in a spiral shape along with the coolant 200, the calculation formula of the centrifugal force received by the bubbles is as follows: (Equation 1); In Equation 1, F c is the centrifugal force received by the bubbles, with the unit of N; ρ lm is the density of the coolant, with the unit of kg / m 3 ; ρ b is the density of the bubbles, with the unit of kg / m 3 ; u θ is the tangential velocity component of the coolant (coolant rotation speed), with the unit of m / s; r is the rotation radius of the position where the bubbles are located, with the unit of m; V b is the volume of the bubbles, with the unit of m 3 .

[0035] In this embodiment, as Figure 1 and Figure 2 shown, the spiral guide vane is located in the area where the second diversion channel 54A intersects the first diversion channel 53A. The spiral guide vane is located in the bottom area of the second diversion channel 54A. The coolant 200 flowing out of the first diversion channel 53A first flows into the spiral guide vane and forms a fluid flowing upward in a spiral shape under its guiding action. The longer channel section of the second diversion channel 54A above the spiral guide vane serves as the flow channel for the spiral fluid, thereby extending the flow path of the spiral fluid, correspondingly extending the collision and coalescence time of the bubbles in the spiral central area, making the effect of the bubbles colliding and coalescing into large bubbles more sufficient, and further increasing the amount of bubbles that break away from the coolant 200 upward and enter the gas cavity 110, and further improving the degassing effect of the degassing structure on the coolant 200.

[0036] In this embodiment, as Figures 1 - 3 shown, a horizontal flow retarder plate 700 is connected to the top end of the vertical guide plate 540. There are openings 70A for the coolant 200 to flow between the horizontal flow retarder plate 700 and the steam generator 400 and the reactor vessel 100, and along the direction away from the reactor core 300, the plate area of the horizontal flow retarder plate 700 gradually increases. The horizontal flow retarder plate 700 is located at the bottom end of the liquid outlet. The coolant 200 after degassing treatment through the second diversion channel 54A carries the remaining bubbles and turns through the top opening 70A and flows to the upper part of the horizontal flow retarder plate 700, and flows along the horizontal flow retarder plate 700 away from the reactor core 300. And as the plate area of the horizontal flow retarder plate 700 increases, the flow rate of the coolant 200 gradually decreases, thereby forming a horizontal slow flow area 70B with a relatively small speed above the horizontal flow retarder plate 700, correspondingly reducing the drag force of the coolant 200 on the bubbles, and at the same time ensuring that the bubbles entering this area can enter the gas cavity 110 with a relatively small upward movement stroke, and further promoting the bubbles entering this area to be able to break away from the capture of the coolant 200 and enter the gas cavity 110 upward, and further improving the degassing effect on the coolant 200.

[0037] Wherein, when the diversion assembly 500 is an annular part, the horizontal flow retarder plate 700 correspondingly extends circumferentially along the annular vertical guide plate 540 to form an annular horizontal plate.

[0038] In this embodiment, as Figure 1 and Figure 3As shown in the figure, in the direction away from the steam generator 400, the horizontal flow retarder plate 700 includes a first flow retarder plate area 710 and a second flow retarder plate area 720. Among them, the first flow retarder plate area 710 is located on the side of the vertical deflector plate 540 facing the steam generator 400, and the second flow retarder plate area 720 is located on the side of the vertical deflector plate 540 facing away from the steam generator 400. On the one hand, while ensuring that the coolant 200 flows between the second diversion channel 54A and the third diversion channel 54B, the horizontal flow retarder plate 700 can effectively increase the flow retarder area of the horizontal flow retarder plate 700, thereby enhancing the flow retarder effect of the horizontal flow retarder plate 700 on the coolant 200, and correspondingly further ensuring the degassing effect when the coolant 200 flows through the horizontal flow retarder area 70B. On the other hand, the first flow retarder plate area 710 extends towards the steam generator 400 above the second diversion channel 54A, causing a certain blockage above the second diversion channel 54A, thereby reducing the channel outlet area at the top of the second diversion channel 54A. When the coolant 200 flows upward through the second diversion channel 54A to the top channel outlet, the flow area decreases, and the flow velocity correspondingly increases. The upward flow velocity of the bubbles entrained therein also increases, thereby further improving the ability of the bubbles to detach upward from the coolant 200 at the channel outlet and subsequent flow to the horizontal flow retarder area 70B and enter the gas cavity 110, and correspondingly further improving the degassing effect on the coolant 200.

[0039] In this embodiment, as Figures 1 - 3 shown, a bubble collection structure 800 is provided above the horizontal flow retarder plate 700. The bubble collection structure 800 is used to collect the bubbles in the coolant 200 flowing through the area where it is located. The bubble collection structure 800 extends downward into the coolant 200 above the horizontal flow retarder plate 700. During the process of the coolant 200 flowing through the horizontal flow retarder area 70B above the horizontal flow retarder plate 700, when the bubbles entrained therein collide with the bubble collection structure 800, they can be collected by the bubble collection structure 800 and move upward along the bubble collection structure 800 under the action of buoyancy to detach from the coolant 200 and enter the gas cavity 110, thereby further improving the degassing effect on the coolant 200.

[0040] Specifically, in this embodiment, as Figures 1 - 3As shown, the bubble collecting structure 800 includes a plurality of collecting vertical rods 810 arranged in parallel and at intervals. The collecting vertical rods 810 are made of a material that is repellent to the coolant 200 and friendly to the bubbles, and the bottom end of the collecting vertical rods 810 extends downward into the coolant 200, and the top end extends upward out of the coolant 200. The material of the collecting vertical rods 810 is determined according to the types of the coolant 200 and the bubbles, so that when the coolant 200 flows through the horizontal slow flow area 70B, the coolant 200 can flow around the collecting vertical rods 810, and the bubbles entrained therein are easily adsorbed on the collecting vertical rods 810, and move upward under the upward pulling force of the buoyancy and the upward guiding action of the collecting vertical rods 810 to separate from the coolant 200 and enter the air cavity 110, thereby realizing the collection effect of the bubble collecting structure 800 on the bubbles; in addition, when the impurities entrained in the coolant 200 flow through the collecting vertical rods 810 and contact with them, they can be adsorbed by them, thereby realizing the collection and cleaning of the impurities in the coolant 200. Specifically, a plurality of collecting vertical rods 810 are arranged in a staggered manner to ensure effective contact between the collecting vertical rods 810 and the coolant 200, and accordingly ensure effective collection of bubbles and impurities in the coolant 200 by the bubble collecting structure 800; wherein, Figures 1 - 3 The number and arrangement of the collecting vertical bars 810 are for illustration only and are not intended to be limiting.

[0041] Specifically, the coolant 200 is made of liquid lead or liquid lead-bismuth alloy, and when the bubbles are water vapor bubbles, the collecting vertical rods 810 can be made of SiC material to achieve the effect of capturing the bubbles.

[0042] In this embodiment, the flow rate of the coolant 200 flowing through the steam generator 400 ranges from 0.1m / s to 0.25m / s. The coolant 200 enters the steam generator 400 through the liquid inlet 521 and flows through the steam generator 400 from top to bottom. When the heat transfer tube of the steam generator 400 ruptures, the bubbles generated by it first enter the coolant 200 flowing therein. In this embodiment, the speed of the coolant 200 flowing through the steam generator 400 is reduced to 0.1m / s to 0.25m / s, thereby effectively reducing the coolant 200's ability to capture bubbles, and correspondingly enhancing the ability of bubbles to float upward and detach from the coolant 200, so that more bubbles can detach from the coolant 200 and enter the air cavity 110 during the process, thereby reducing the occurrence of bubbles being entrained into the core 300 and causing adverse effects on it.

[0043] The drag force generated by the coolant 200 on the bubbles can represent the ability of the coolant 200 to capture the bubbles. The drag force calculation formula is as follows: (Formula 2); In formula 2, F d is the drag force exerted by the coolant on the bubble, in N; C d is the drag coefficient, dimensionless; ρlm is the density of the coolant, with the unit of kg / m 3 ; u is the difference between the coolant flow velocity and the bubble flow velocity, with the unit of m / s; A is the projected area of the bubble in the flow direction, with the unit of m 2 .

[0044] As can be seen from Equation 2, the greater the flow velocity of the coolant 200, the greater the difference u between the coolant 200 and the bubble flow velocity. Correspondingly, the greater the drag force exerted by the coolant 200 on the bubble, the stronger the ability of the coolant 200 to capture the bubble, and the weaker the ability of the bubble to break away from the coolant 200. In this embodiment, by reducing the flow velocity of the coolant 200, the ability of the coolant 200 to capture the bubble is reduced, and correspondingly, the ability of the bubble to float upward and break away from the coolant 200 is enhanced, thereby improving the degassing effect of the coolant 200.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A lead-cooled nuclear reactor with steam generator rupture accident mitigation technology, characterized in that: The invention comprises a stack container (100) in which a coolant (200) is accommodated in a lower region, wherein a stack core (300), a steam generator (400) and a flow guide assembly (500) are arranged in the stack container (100), wherein the flow guide assembly (500) has a flow guide cavity (50A) with a top port (510) being open, and a lower section of the steam generator (400) extends into the flow guide cavity (50A) through the top port (510), wherein the flow guide assembly (500) comprises: a vertical baffle (520), located between the steam generator (400) and the core (300), with a top end higher than the coolant (200), and provided with a liquid inlet (521) for the coolant (200) to flow into the steam generator (400); a bottom guide plate (530), located below the steam generator (400), and forming a first guide channel (53A) for the coolant (200) to flow between the bottom guide plate and the steam generator (400); and, a vertical guide plate (540) located on a side of the steam generator (400) away from the core (300), a second guide channel (54A) for the coolant (200) to flow upward is formed between the vertical guide plate (540) and the steam generator (400), a liquid outlet for the coolant (200) to flow out is formed above, and a third guide channel (54B) for the coolant (200) to flow downward is formed between the vertical guide plate (540) and the side wall of the stack container (100); The second flow guide channel (54A) is provided with a spoiler (600), and the spoiler (600) is capable of spoiling the coolant (200) flowing through the second flow guide channel (54A).

2. The lead-cooled nuclear reactor according to claim 1, characterized in that: The guide cavity (50A) is annular and is arranged around the outer periphery of the core (300); there are a plurality of steam generators (400), and the plurality of steam generators (400) are arranged around the outer periphery of the core (300) along the circumferential direction, and the lower sections of the plurality of steam generators (400) extend into the guide cavity (50A) through the top port (510).

3. The lead-cooled nuclear reactor according to claim 1, characterized in that: The spoiler (600) comprises a spiral guide plate extending in a spiral shape from bottom to top.

4. The lead-cooled nuclear reactor according to claim 3, characterized in that: The spiral guide plate is located in a region where the second guide channel (54A) intersects the first guide channel (53A).

5. The lead-cooled nuclear reactor according to claim 1 or 2, characterized in that: A horizontal slow-flow plate (700) is connected to the top of the vertical guide plate (540), and openings (70A) for coolant (200) to flow are reserved between the horizontal slow-flow plate (700) and the steam generator (400) and the reactor container (100), and the plate surface area of ​​the horizontal slow-flow plate (700) gradually increases in a direction away from the reactor core (300).

6. The lead-cooled nuclear reactor according to claim 5, characterized in that: Along a direction away from the steam generator (400), the horizontal slow flow plate (700) comprises a first slow flow plate area (710) and a second slow flow plate area (720), wherein the first slow flow plate area (710) is located on a side of the vertical guide plate (540) facing the steam generator (400), and the second slow flow plate area (720) is located on a side of the vertical guide plate (540) facing away from the steam generator (400).

7. The lead-cooled nuclear reactor according to claim 5, characterized in that: A bubble collection structure (800) is provided above the horizontal slow flow plate (700), and the bubble collection structure (800) is used to collect bubbles in the coolant (200) flowing through the corresponding area.

8. The lead-cooled nuclear reactor according to claim 7, characterized in that: The bubble collection structure (800) comprises a plurality of vertical collection rods (810) arranged in parallel, the vertical collection rods (810) being made of a material that is repellent to the coolant (200) and friendly to bubbles, and the bottom ends of the vertical collection rods (810) extend downward into the coolant (200) and the top ends extend upward out of the coolant (200).

9. The lead-cooled nuclear reactor according to claim 1 or 2, characterized in that: The flow rate of the coolant (200) flowing through the steam generator (400) ranges from 0.1 m / s to 0.25 m / s.

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