lead bismuth pile

Abstract

The embodiment of the present application provides a lead-bismuth reactor, which comprises a reactor core, a reactor vessel, a reactor core containment plate and lead-bismuth coolant. The reactor core and the reactor core containment plate are arranged in the reactor vessel, and the reactor core containment plate is arranged outside the reactor core to define a containment plate space for accommodating the lead-bismuth coolant entering the reactor core. Different channels are arranged at different heights of the reactor core containment plate, and the lead-bismuth coolant can flow out of the containment plate space through the channels, wherein the channels at a lower position are used for the lead-bismuth coolant to flow out of the space in a normal condition, and the channels at a higher position are used for the lead-bismuth coolant to flow out of the containment plate space in an accident condition; the lead-bismuth reactor further comprises a floating ring arranged inside the reactor core containment plate, the floating ring floats on the liquid surface of the lead-bismuth coolant, and is used for closing the channels at the higher position of the reactor core containment plate in the normal condition and opening the channels at the higher position of the reactor core containment plate in the accident condition. The embodiment of the present application is beneficial to discharging the residual heat of the reactor core in the accident condition.

Description

Technical Field

[0001] This application relates to the field of reactor technology, and in particular to a lead-bismuth reactor. Background Technology

[0002] This section is only intended to provide background information relevant to this application and does not necessarily constitute prior art.

[0003] Lead-bismuth reactors utilize pumps located within the reactor vessel to drive the flow of lead-bismuth coolant, transferring heat from the reactor core to a heat exchanger, which then removes the heat from the reactor vessel. In the event of pump failure, natural circulation is required to dissipate the heat from the core and prevent a sustained rise in core temperature that could lead to a serious accident. Summary of the Invention

[0004] A brief overview of this application is provided below to offer a basic understanding of certain aspects thereof. It should be understood that this overview is not an exhaustive summary of the application. It is not intended to identify key or essential parts of the application, nor is it intended to limit its scope. Its purpose is merely to present certain concepts in a simplified form as a prelude to the more detailed description that follows.

[0005] Embodiments of this application provide a lead-bismuth reactor, comprising: a reactor core, a reactor vessel, a core shroud, and lead-bismuth coolant. The reactor core and the core shroud are disposed within the reactor vessel, with the core shroud disposed outside the reactor core and defining a shroud space for accommodating the lead-bismuth coolant entering the reactor core. Different channels are provided at different heights of the core shroud, through which the lead-bismuth coolant can flow out of the shroud space. The channels at lower positions are used for the lead-bismuth coolant to flow out of the shroud space under normal operating conditions, while the channels at higher positions are used for the lead-bismuth coolant to flow out of the shroud space under accident conditions. The lead-bismuth reactor also includes a floating ring disposed inside the core shroud. The floating ring floats on the surface of the lead-bismuth coolant and is used to close the channels at higher positions of the core shroud under normal operating conditions and to open the channels at higher positions of the core shroud under accident conditions.

[0006] The embodiments of this application optimize the design of the core shroud channels and set floating rings inside the core shroud, which can form a natural circulation flow path to cool the core under accident conditions, thereby facilitating the removal of residual core heat.

[0007] These and other advantages of this application will become more apparent from the following detailed description of preferred embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0008] To further illustrate the above and other advantages and features of this application, the specific embodiments of this application will be described in more detail below with reference to the accompanying drawings. The drawings, together with the following detailed description, are included in and form a part of this specification. Elements having the same function and structure are indicated by the same reference numerals. It should be understood that these drawings only depict typical examples of this application and should not be considered as limiting the scope of this application.

[0009] Figure 1 The flow path of the lead-bismuth coolant in the lead-bismuth stack according to an embodiment of this application is shown when the pump is in normal operating condition;

[0010] Figure 2 The flow path of the lead-bismuth coolant in the lead-bismuth stack according to an embodiment of this application is shown when the pump is in a faulty condition;

[0011] Figure 3 yes Figure 1 A partially enlarged schematic diagram of the lead-bismuth pile shown;

[0012] Figure 4 yes Figure 2 A partially enlarged schematic diagram of the lead-bismuth pile shown.

[0013] It should be noted that the accompanying drawings are not necessarily drawn to scale, but are shown only in a schematic manner without affecting the reader's understanding.

[0014] Explanation of reference numerals in the attached figures:

[0015] 10. Reactor core;

[0016] 21. Container body; 22. Stacking cover; 23. Protective container;

[0017] 30. Core shroud; 301. Shroud space; 31. High-level duct; 32. Low-level duct;

[0018] 40. Floating ring; 41. Channel;

[0019] 50. Heat exchanger; 51. Heat exchanger shell; 511. Heat exchange inlet; 512. Heat exchange outlet;

[0020] 61. Outer outer casing; 62. Partition plate; 63. Annular bottom plate; 631. Through hole;

[0021] 64. Connecting pipes;

[0022] 70. Pump; 71. Pump casing; 711. Coolant inlet; 712. Coolant outlet;

[0023] 80. Reactor core entrance;

[0024] 200. Coolant level;

[0025] 300. Coolant level;

[0026] 500, space; 600, space; 700, flow path space. Detailed Implementation

[0027] Exemplary embodiments of this application will be described below with reference to the accompanying drawings. For clarity and brevity, not all features of actual implementations are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the development of any such actual embodiment to achieve the developer's specific goals, such as meeting constraints related to the system and business, and these constraints may vary depending on the implementation. Furthermore, it should be understood that while development work can be very complex and time-consuming, such development work is merely a routine task for those skilled in the art who benefit from the content of this application.

[0028] It should also be noted that, in order to avoid obscuring this application with unnecessary details, only the equipment structure and / or processing steps closely related to the solution according to this application are shown in the accompanying drawings, while other details that are not closely related to this application are omitted.

[0029] It should be noted that, unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning as understood by a person with ordinary skills in the field to which this application pertains.

[0030] In the description of the embodiments of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0031] In lead-bismuth reactors, during pump failure accidents, the core heat must be removed through natural circulation of the lead-bismuth coolant. Currently, the internal flow channel arrangement of lead-bismuth reactors is not conducive to the natural circulation of the lead-bismuth coolant.

[0032] To address the aforementioned technical problems, embodiments of this application provide a lead-bismuth stack. See also... Figure 1 and Figure 2 , Figure 1 The flow path of the lead-bismuth coolant in the lead-bismuth stack according to an embodiment of this application is shown when the pump is in normal operating condition; Figure 2 The diagram illustrates the flow path of the lead-bismuth coolant in a lead-bismuth stack under pump failure (i.e., accident condition) according to an embodiment of this application. The arrows in the diagram indicate the flow direction of the coolant.

[0033] An embodiment of this application provides a lead-bismuth reactor, comprising: a reactor core 10, a reactor vessel, a core shroud 30, and a lead-bismuth coolant. The lead-bismuth coolant, the reactor core 10, and the core shroud 30 are disposed within the reactor vessel. The core shroud 30 is disposed outside the reactor core 10 and defines a shroud space 301 for accommodating the lead-bismuth coolant entering the reactor core 10. Different channels are provided at different heights of the core shroud 30, through which the lead-bismuth coolant can flow out of the shroud space 301. The channel 32 at a lower position (hereinafter referred to as the low-level channel 32) is used for the lead-bismuth coolant to flow out of the shroud space 301 under normal operating conditions, while the channel 31 at a higher position (hereinafter referred to as the high-level channel 31) is used for the lead-bismuth coolant to flow out of the shroud space 301 under accident conditions.

[0034] The lead-bismuth reactor may also include a floating ring 40, which is disposed inside the core enclosure 30 and floats on the lead-bismuth coolant surface 300. The floating ring 40 is used to close the high-level channel 31 of the core enclosure 30 under normal operating conditions and to open the high-level channel 31 of the core enclosure 30 under accident conditions.

[0035] The lead-bismuth reactor provided in the embodiments of this application has different channels at different heights of the core shroud 30, and a floating ring 40 is provided inside the core shroud 30. Under normal operating conditions, the floating ring 40 closes the high-level channel 31 of the core shroud 30, so that the lead-bismuth coolant in the shroud space 301 flows out of the shroud space 301 from the low-level channel 32, forming a forced circulation path under normal operating conditions. Under accident operating conditions, the floating ring 40 opens the high-level channel 31 of the core shroud 30, so that the lead-bismuth coolant in the shroud space 301 flows out of the shroud space 301 from the high-level channel 31, thereby forming a natural circulation path in the reactor vessel under accident operating conditions.

[0036] Therefore, it can be seen that the embodiments of this application, by optimizing the design of the channels of the core shroud 30 and setting the floating ring 40 inside the core shroud 30, can form a natural circulation flow path to cool the core 10 under accident conditions, thereby facilitating the removal of residual heat from the core 10.

[0037] The core enclosure 30 can serve to support the core 10 and provide shielding.

[0038] In some embodiments, the lead-bismuth stack may further include a pump 70 disposed within the stack container and located radially outside the core enclosure 30. The pump 70 is used to provide power for forced circulation of the lead-bismuth coolant.

[0039] In this embodiment of the application, under normal operating conditions, the coolant liquid level 300 in the core enclosure 30 is higher than the high-level channel 31 and higher than the coolant liquid level 200 in the reactor vessel. At this time, the high-level channel 31 is closed by the floating ring 40. The high-temperature lead-bismuth coolant from the core 10 flows out of the enclosure space 301 through the low-level channel 32 and then flows to the bottom of the core 10 under the drive of the pump 70, re-enters the core 10, and forms a forced circulation flow path to cool the core 10.

[0040] In the event of a pump 70 failure, the coolant level 300 in the core shroud 30 drops, while the coolant level 200 in the reactor vessel rises until the coolant level 300 and coolant level 200 are level. The coolant level 300 and coolant level 200 are higher than the high-level orifice 31. At this time, the high-level orifice 31 is opened by the floating ring 40, allowing the high-temperature lead-bismuth coolant from the core 10 to flow out of the shroud space 301 through the high-level orifice 31, then flow downwards to the bottom of the core 10, re-entering the core 10 to form a natural circulation path for cooling the core 10 and thus dissipating residual heat.

[0041] See Figure 3 and Figure 4 In some embodiments, a channel 41 is formed at a predetermined position of the floating ring 40. When the floating ring 40 moves downward as the coolant level 300 decreases, the channel 41 of the floating ring 40 communicates with the high-level channel 31 of the core shroud 30, thereby opening the high-level channel 31. In such an embodiment, when the pump 70 fails, the lead-bismuth coolant level 300 in the shroud space 301 decreases, and the floating ring 40 automatically moves downward as the coolant level 300 decreases, opening the high-level channel 31. Therefore, under accident conditions, the lead-bismuth reactor of this embodiment can automatically form a natural circulation path to cool the core 10.

[0042] In some embodiments, the diameter of the channel 41 of the floating ring 40 is larger than the diameter of the high-level channel 31 of the core shroud 30, so as to facilitate communication between the channel of the floating ring 40 and the high-level channel 31 of the core shroud 30 after the coolant level 300 drops.

[0043] In some embodiments, the total amount of coolant injected into the reactor vessel can be controlled so that when the coolant level 300 in the shroud space 301 drops to be level with the coolant level 200 in the reactor vessel, the channel of the floating ring 40 can communicate with the high-level channel 31 of the reactor core shroud 30.

[0044] In some embodiments, the density of the floating ring 40 is less than that of the lead-bismuth coolant, so that the floating ring 40 can float at the surface 300 of the lead-bismuth coolant.

[0045] In some embodiments, the floating ring 40 is clearance-fitted with the core shroud 30. In such embodiments, the floating ring 40 can move up and down with the coolant level 300 within the core shroud 30, while also providing a good sealing effect for the high-level channel 31.

[0046] In some embodiments, the reactor vessel includes a vessel body 21 having an upper opening and a reactor cap 22 for closing the upper opening of the vessel body 21. The reactor cap 22 and the vessel body 21 together define an enclosure boundary forming a primary loop for containing lead-bismuth coolant. In some embodiments, the upper end of the core shroud 30 is connected to the reactor cap 22 to make the space above the lead-bismuth coolant level 300 within the shroud space 301 a sealed space, thereby facilitating that the coolant level 300 within the shroud space 301 is higher than the coolant level 200 within the reactor vessel.

[0047] In some embodiments, the core shroud 30 has a core inlet 80 at its bottom opening for allowing lead-bismuth coolant to flow into the core 10. The lead-bismuth coolant entering the core inlet 80 flows upward within the core 10 to the shroud space 301 at the top of the core 10.

[0048] In some embodiments, the lead-bismuth stack may further include a heat exchanger 50 and in-core components. The heat exchanger 50 and in-core components are disposed within the stack container and located radially outside the core enclosure 30. The in-core components and the core enclosure 30 together define a flow path space 700 located radially outside the enclosure space 301. The coolant inlet 711 of the pump 70 is located in the flow path space 700, and the coolant outlet 712 of the pump 70 is in fluid communication with the core inlet 80 outside the flow path space 700. Lead-bismuth coolant flowing out from the lower orifice 32 of the core enclosure 30 flows into the heat exchanger 50, from the heat exchanger 50 into the flow path space 700, and from the flow path space 700 into the pump 70.

[0049] In some embodiments, the high-level channel 31 of the core shroud 30 is positioned above the upper end of the in-core components, and the lead-bismuth coolant flowing out of the high-level channel 31 flows directly into the core 10. This direct flow into the core 10 can be understood as the lead-bismuth coolant not flowing through the pump 70 and the flow path space 700 during its flow into the core inlet 80.

[0050] In the above embodiments, the core enclosure space 301 of the core enclosure 30 is in fluid communication with the coolant outlet 712 of the pump 70 through the core inlet 80, and the flow path space 700 outside the core enclosure space 301 is in fluid communication with the coolant inlet 711 of the pump 70. Thus, by adjusting the power of the pump 70, a liquid level difference can be created between the interior and exterior of the core enclosure space 301. In some embodiments, the pump 70 is configured to ensure that the coolant liquid level 300 inside the core enclosure space 301 is higher than the coolant liquid level 200 outside the core enclosure space 301.

[0051] In some embodiments, the in-core components include an outer shroud 61 disposed radially outward of the core shroud 30 and an annular bottom plate 63. The radially adjacent edges of the annular bottom plate 63 are connected to the lower ends of the outer shroud 61 and the core shroud 30, respectively, to define the aforementioned flow path space 700. A pump 70 and a heat exchanger 50 are disposed radially inward of the outer shroud 61.

[0052] In some embodiments, the pump 70 includes a pump housing 71 extending downward from the stack cover to a bottom plate, a coolant inlet 711 being disposed on the side wall of the pump housing 71, an opening being formed at the bottom of the pump housing 71 to serve as a coolant outlet 712 for the pump 70, and a through hole 631 being formed at the opening of the annular bottom plate 63 corresponding to the opening of the pump housing 71, so that the lead-bismuth coolant flowing out from the coolant outlet 712 can flow to the bottom of the annular bottom plate 63 and flow to the core inlet 80.

[0053] Under normal operating conditions, the lead-bismuth coolant flowing out from the low-level channel 32 of the core shroud 30 enters the flow path space 700 and is driven by the pump 70 to enter the coolant inlet 711. It then enters the space 600 below the annular bottom plate 63 through the coolant outlet 712, and then enters the core 10 through the core inlet 80. After cooling the core 10, it flows upward into the shroud space 301, forming a forced circulation flow path.

[0054] Under accident conditions, the lead-bismuth coolant flowing out from the high-level channel 31 of the core shroud 30 can enter the radially outer space 500 of the outer shroud 61 above the outer shroud 61, and flow downward to the space 600 below the annular bottom plate 63. Then, it enters the core 10 through the core inlet 80, cools the core 10, and flows upward into the shroud space 301, forming a natural circulation path.

[0055] In some embodiments, the heat exchanger 50 is disposed radially inside the outer shroud 61 above the annular base plate 63. The heat exchanger 50 includes a heat exchanger housing 51, which has a coolant heat exchange inlet 511 for lead-bismuth coolant inflow and a coolant heat exchange outlet 512 for lead-bismuth coolant outflow. The coolant heat exchange inlet 511 is connected to a low-level channel 32 of the core shroud 30 via a connecting pipe 64. The lead-bismuth coolant flowing out of the low-level channel 32 can only enter the coolant heat exchange inlet 511 and cannot directly enter the flow path space 700. The coolant heat exchange outlet 512 is lower than the upper end of the outer shroud 61 so that the coolant heat exchange outlet 512 does not traverse the outer shroud 61.

[0056] In some embodiments, the in-core components may further include a baffle 62 disposed between the heat exchanger 50 and the pump 70. The lower end of the baffle 62 is connected to an annular bottom plate 63, which divides the flow path space 700 into a pump space and a heat exchanger space. The height of the baffle 62 is the same as the height of the outer casing 61. The coolant heat exchange outlet 512 may be located at the bottom of the heat exchanger shell 51. Because of the baffle 62, the lead-bismuth coolant flowing out of the coolant heat exchange outlet 512 needs to be pushed upwards over the baffle 62 to enter the pump space. Therefore, this effectively increases the flow resistance of the lead-bismuth coolant flowing into the coolant inlet 711 of the pump 70 from the baffle space 301. At the same time, the lead-bismuth coolant flowing out of the coolant outlet 712 of the pump 70 can flow into the core inlet 80 without obstruction. This further facilitates the coolant liquid level 300 in the baffle space 301 to be higher than the coolant liquid level 200 in the external space of the baffle space 301. On the other hand, in the event of an accident, it also facilitates the flow of the lead-bismuth coolant in the baffle space 301 out of the baffle space 301 through the high-level channel 31.

[0057] In some embodiments, the lead-bismuth reactor may further include a coolant flow distributor disposed at the lower opening of the core shroud 30, forming a core inlet 80. Lead-bismuth coolant below the core shroud 30 enters the core 10 through the coolant flow distributor.

[0058] In some embodiments, the reactor vessel further includes a protective container 23 formed radially outside the vessel body 21. The protective container 23 and the interior of the vessel body 21 may define a containment space containing a cooling medium. An outer shroud 61 may be disposed adjacent to the vessel body 21 so that lead-bismuth coolant entering the radially outer space 500 of the outer shroud 61 under accident conditions can be cooled by the vessel body 21 as it flows downward, thereby enhancing the removal of residual heat from the reactor core 10.

[0059] The lead-bismuth reactor provided in the embodiments of this application can be a compact pool-type lead-bismuth reactor. Without affecting the internal structure of the reactor, the coolant flow path can be passively altered by the free liquid level changes caused by the operation of pump 70, simplifying the natural circulation channel. During normal reactor operation, the existing liquid level difference causes the floating ring 40 to close the high-level orifice 31, forcing the lead-bismuth coolant to circulate only through the forced circulation path, thus preventing ineffective bypass flow. In the event of a pump 70 failure, the liquid level difference disappears, the floating ring 40 drops in height and connects with the high-level orifice 31, forming a new flow channel. The lead-bismuth coolant can then flow directly from the reactor core 10 to the reactor vessel wall, avoiding the influence of the complex loop structure on the coolant flow rate, thereby enhancing heat dissipation capacity and playing a crucial role in improving the inherent safety of the reactor.

[0060] Regarding the embodiments of this application, it should also be noted that, without conflict, the embodiments of this application and the features in the embodiments can be combined with each other to obtain new embodiments.

[0061] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. The scope of protection of this application shall be determined by the scope of the claims.

Claims

1. A lead-bismuth stack, comprising: The reactor core, reactor vessel, core enclosure, and lead-bismuth coolant are provided, wherein the reactor core and the core enclosure are disposed within the reactor vessel, and the core enclosure is disposed outside the reactor core, defining an enclosure space for accommodating the lead-bismuth coolant entering the reactor core. Different channels are provided at different heights of the core enclosure, through which the lead-bismuth coolant can flow out of the enclosure space. The channels at lower positions are used for the lead-bismuth coolant to flow out of the enclosure space under normal operating conditions, while the channels at higher positions are used for the lead-bismuth coolant to flow out of the enclosure space under accident conditions. The lead-bismuth reactor also includes a floating ring disposed inside the core enclosure. The floating ring floats on the surface of the lead-bismuth coolant and is used to seal the channels at higher positions of the core enclosure under normal operating conditions and to open the channels at higher positions of the core enclosure under accident conditions. The floating ring is fitted with the core surround plate with a clearance. The floating ring has a channel formed at a predetermined position. When the floating ring moves downward as the liquid level of the lead-bismuth coolant drops, the channel of the floating ring communicates with the channel at a higher position of the core shroud. The diameter of the duct in the floating ring is larger than the diameter of the duct at a higher position in the core shroud.

2. The lead-bismuth pile according to claim 1, wherein, The bottom opening of the core enclosure is provided with a core inlet for allowing lead-bismuth coolant to flow into the core. The lead-bismuth stack also includes a heat exchanger, stack internals, and pumps. The heat exchanger, the in-core components, and the pump are disposed within the reactor vessel and located radially outside the reactor core enclosure. The in-core components and the reactor core enclosure together define a flow path space located radially outside the enclosure space. The coolant inlet of the pump is located in the flow path space, and the coolant outlet of the pump is outside the flow path space and in fluid communication with the reactor core inlet. Lead-bismuth coolant flowing from the orifice at the lower position of the core enclosure flows into the heat exchanger, from the heat exchanger into the flow path space, and from the flow path space into the pump.

3. The lead-bismuth pile according to claim 2, wherein, The duct at the higher position of the core enclosure is positioned above the upper end of the internal components, and the lead-bismuth coolant flowing out of the duct at the higher position flows directly into the core.

4. The lead-bismuth pile according to claim 2, wherein, The pump is configured to raise the coolant level within the enclosure space to a higher level than the coolant level in the external space of the enclosure space.

5. The lead-bismuth pile according to claim 3, wherein, The in-core components include: an annular bottom plate and an outer shroud disposed radially outside the core shroud, wherein the radially adjacent edges of the annular bottom plate are respectively connected to the lower ends of the outer shroud and the lower ends of the core shroud to define the flow path space. The pump and heat exchanger are located radially inside the outer casing.

6. The lead-bismuth pile according to claim 5, wherein, The pump includes a pump housing extending downward from the top wall of the reactor vessel to a connection with the annular base plate. The coolant inlet is located on the side wall of the pump housing. An opening is formed at the bottom of the pump housing to serve as the coolant outlet. A through-hole is formed in the annular base plate corresponding to the opening of the pump housing, allowing lead-bismuth coolant flowing from the coolant outlet to flow below the annular base plate and to the reactor core inlet. Under normal operating conditions, the lead-bismuth coolant flowing out from the holes at the lower position of the core shroud enters the flow path space and, driven by the pump, enters the coolant inlet and then enters the space below the annular bottom plate via the coolant outlet. Under accident conditions, the lead-bismuth coolant flowing out from the orifices at the higher position of the core shroud can enter the radially outer side of the outer shroud above the outer shroud and flow downward to the space below the annular bottom plate.

7. The lead-bismuth pile according to claim 5, wherein, The heat exchanger is disposed radially inside the outer casing above the annular base plate. The heat exchanger includes a heat exchanger shell, on which a heat exchange inlet for the inflow of lead-bismuth coolant and a heat exchange outlet for the outflow of lead-bismuth coolant are provided. The heat exchange inlet is connected to the low-level channel of the core enclosure plate via a connecting pipe; The heat exchange outlet is lower than the upper end of the outer casing.

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