Pool-type steam generator

Abstract

An embodiment of this application provides a pool-type steam generator, comprising: an inner cylinder forming a accommodating space suitable for housing a reactor core and shell-side medium; at least one shell-side medium inlet is provided at the upper part of the inner cylinder for introducing shell-side medium heated by the reactor core; and a shell-side medium outlet is provided at the bottom of the inner cylinder, wherein the shell-side medium is liquid metal; an outer cylinder fitted inside the inner cylinder, forming an annular space between the outer cylinder and the inner cylinder; a plurality of threaded pipes disposed within the annular space, each threaded pipe including a tube-side medium inlet at the bottom and a steam outlet at the top, wherein the tube-side medium flowing upward within the threaded pipe undergoes countercurrent heat exchange with the shell-side medium to become steam, which flows out from the steam outlet; and a pumping assembly connected to the shell-side medium inlet, the pumping assembly being suitable for pumping the shell-side medium heated by the reactor core from the shell-side medium inlet into the annular space.

Description

Technical Field

[0001] Embodiments of this application relate to a direct current steam generator, and more particularly to an integrated large coil pool steam generator for use in liquid metal reactors. Background Technology

[0002] With the development of new technologies, liquid metal reactors are commonly used in industries such as nuclear power, energy, electricity, chemical industry, pharmaceuticals, and petroleum. Liquid metal reactors refer to reactors that use liquid metal as a coolant, mainly including sodium-cooled fast reactors, lead-bismuth fast reactors, lead-cooled reactors, sodium-potassium reactors, lithium-potassium reactors, lead-lithium reactors, liquid mercury reactors, and other metal reactors not listed in detail. The steam generator, as the hub for heat transfer between the primary and secondary sides of the liquid metal reactor, is a key piece of equipment in the reactor, and its safety is of paramount importance.

[0003] In related technologies, common direct current steam generators have a small reactor space, ample space for assembly and welding, making them difficult to assemble and manufacture. In addition, they also suffer from the defect of uneven medium flow rate inside the heat exchange tubes. Summary of the Invention

[0004] To address at least one of the aforementioned or other technical problems, embodiments of this application provide a pool-type steam generator. The steam generator has a large central area suitable for arranging the reactor core and control rod drive mechanism, providing ample space for assembly and welding, making it suitable for integrated reactors. The pool-type steam generator includes: an inner cylinder forming a receiving space suitable for housing the reactor core and shell-side medium; at least one shell-side medium inlet is provided at the upper part of the inner cylinder, allowing the introduction of shell-side medium heated by the reactor core; and a [missing information - likely a design feature] is provided at the bottom of the inner cylinder. It has a shell-side medium outlet, wherein the shell-side medium is liquid metal; an outer cylinder, which is fitted inside the inner cylinder, forming an annular space between the outer cylinder and the inner cylinder; multiple threaded pipes, which are arranged in the annular space, including a tube-side medium inlet located at the bottom and a steam outlet located at the top, wherein the tube-side medium flowing from bottom to top in the threaded pipe exchanges heat with the shell-side medium in a countercurrent manner and turns into steam, which flows out from the steam outlet; and a pumping assembly, which is connected to the shell-side medium inlet, and is suitable for pumping the shell-side medium heated by the reactor core from the shell-side medium inlet into the annular space.

[0005] According to the embodiments of this application, the pool-type steam generator uses an outer cylinder to enclose an inner cylinder, and places the threaded pipe in the space between the two. Superheated steam is obtained through countercurrent heat exchange between the shell-side medium and the tube-side medium. This increases the space inside the inner cylinder, reduces the difficulty of assembly and welding, and also reduces the installation difficulty of the reactor core and control rod drive mechanism installed inside the inner cylinder. Attached Figure Description

[0006] Figure 1 This is a perspective view of a pool-type steam generator according to an exemplary embodiment of this application;

[0007] Figure 2 yes Figure 1 A perspective view of the aforementioned pool-type steam generator;

[0008] Figure 3 yes Figure 1 A three-dimensional view of the internal structure of a pool-type steam generator is shown.

[0009] Figure 4 yes Figure 3 A magnified schematic diagram of a portion of the internal structure shown;

[0010] Figure 5 The diagram schematically shows a front view of the tube bundle support assembly of a pool-type steam generator according to an embodiment of this application.

[0011] The meanings of the reference numerals in the above figures are as follows:

[0012] 1-Inner cylinder;

[0013] 2-Shell-side medium inlet;

[0014] 3-Outer cylinder;

[0015] 4-Threaded pipe;

[0016] 5-Upper perforated plate;

[0017] 6-Lower orifice plate;

[0018] 7-Pipeside inlet header;

[0019] 8-Entrance takeover;

[0020] 9-Downcomer;

[0021] 10 - Pipe-side outlet header;

[0022] 11-Steam outlet;

[0023] 12-Coil inlet connecting pipe;

[0024] 13-Coil outlet connection pipe;

[0025] 14-Throttling element;

[0026] 15-Supporting bar;

[0027] 16-Fasteners; and

[0028] 17-Top cover plate. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0030] However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of this application. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of this application for ease of explanation. However, it will be apparent that one or more embodiments may be implemented without these specific details. Furthermore, descriptions of well-known technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0031] This application Figure 1 This is a perspective view of a pool-type steam generator according to an exemplary embodiment of this application; Figure 2 yes Figure 1 A perspective view of the aforementioned pool-type steam generator; Figure 3 yes Figure 1 The diagram shows a three-dimensional view of the internal structure of a pool-type steam generator.

[0032] This application provides a pool-type steam generator, such as... Figures 1 to 3 As shown, the system includes: an inner cylinder 1, an outer cylinder 3, and a pumping assembly. The inner cylinder 1 forms a accommodating space suitable for housing the reactor core and shell-side medium. At least one shell-side medium inlet 2 is provided at the upper part of the inner cylinder 1, allowing the introduction of shell-side medium heated by the reactor core. A shell-side medium outlet is provided at the bottom of the inner cylinder 1, wherein the shell-side medium is liquid metal. The outer cylinder 3 is fitted onto the inner cylinder 1, forming an annular space between them. Multiple threaded pipes 4 are arranged within the annular space. Each threaded pipe 4 includes a tube-side medium inlet at the bottom and a steam outlet 11 at the top. The tube-side medium flowing upwards within the threaded pipe 4 undergoes countercurrent heat exchange with the shell-side medium flowing downwards within the annular space, transforming into steam which flows out from the steam outlet 11. The pumping assembly is connected to the shell-side medium inlet and is suitable for pumping the shell-side medium, which has been heated by the reactor core, from the shell-side medium inlet into the annular space.

[0033] In this embodiment, by using an outer cylinder to enclose an inner cylinder, the threaded tube is placed in the space between the two. Superheated steam is obtained through countercurrent heat exchange between the shell-side medium and the tube-side medium, increasing the space inside the inner cylinder and reducing the difficulty of assembly and welding. Furthermore, the installation difficulty of the reactor core and control rod drive mechanism installed inside the inner cylinder is reduced.

[0034] According to some embodiments of this application, the pipeline medium includes water.

[0035] According to some embodiments of this application, the pool-type steam generator further includes an upper orifice plate 5 and a lower orifice plate 6. The upper orifice plate 5 is disposed in the annular space and has multiple inlet holes. The upper orifice plate 5 is located between the top of the threaded pipe 4 and the shell-side medium inlet 2, and is configured to uniformly distribute the shell-side medium flowing into the shell-side medium inlet 2. The lower orifice plate 6 is disposed in the annular space and is located between the bottom of the threaded pipe 4 and the shell-side medium outlet. The lower orifice plate 6 has multiple outlet holes suitable for uniformly discharging the shell-side medium, allowing the shell-side medium that has completed counter-current heat exchange to flow back into the inner cylinder 1 for reheating.

[0036] In this embodiment, the interior of the inner cylinder 1 of the pool-type steam generator is the space for arranging the reactor core and control rod drive mechanism. The liquid metal medium (shell-side medium) heated by the reactor core is pumped by the pumping assembly to the upper space of the inner side region of the inner cylinder 1, and enters the shell side (annular space) of the steam generator through the shell-side medium inlet 2. After being evenly distributed by the upper orifice plate 5, it undergoes heat exchange through the tube bundle region (threaded tube 4), and flows back to the reactor through the lower orifice plate 6. After being heated again, it is pumped to the shell-side medium inlet 2 for circulation.

[0037] According to some embodiments of this application, both the upper orifice plate 5 and the lower orifice plate 6 are annular plates, and their sizes match the cross-sectional dimensions of the annular space. The upper orifice plate 5 and the lower orifice plate 6 have multiple small holes arranged circumferentially at different diameters. The number, diameter, and distribution of the small holes need to be determined through thermo-hydraulic analysis calculations in conjunction with the flow field distribution of the liquid metal. Before the shell-side medium enters the annular space through the shell-side medium inlet 2, the upper orifice plate 5 performs flow equalization on the incoming shell-side medium, ensuring that the shell-side fluid and tube-side fluid are evenly distributed across the annular surface of the upper orifice plate before heat exchange, thus ensuring sufficient heat exchange between the shell-side and tube-side media.

[0038] According to some embodiments of this application, the pool-type steam generator further includes a tube-side inlet header 7 and downcomers 9. The tube-side inlet header 7 is disposed at the top of the annular space, and an inlet pipe 8 is provided on the tube-side inlet header, which is suitable for introducing tube-side medium. There are multiple downcomers 9, the upper end of each downcomer 9 is connected to the tube-side inlet header 7, and the lower end is connected to the tube-side medium inlet of the threaded pipe 4.

[0039] According to some embodiments of this application, the pool-type steam generator further includes a tube-side outlet header 10, which is disposed at the top of the annular space and is connected to the upper end of the threaded pipe 4. A steam outlet 11 is provided on the tube-side outlet header 10.

[0040] In this embodiment, the tube-side medium is first fed through the tube-side inlet pipe 8, and then diverted through the tube-side inlet header 7. It first flows downward through the downcomer 9, and then turns back at the bottom to enter the rising zone, where the tube bundle is a threaded tube 4. In the rising zone, the feedwater is gradually heated into superheated steam in the spiral heat exchange tubes. After merging through the tube-side outlet header, it is output through the steam outlet pipe 11.

[0041] According to some embodiments of this application, the inner cylinder 1 is a complete cylinder with a relatively large diameter, the specific diameter of which is determined according to the specific reactor type and application requirements. The inner cylinder 1 houses the pump assembly and control rod drive mechanism. Multiple circular holes (i.e., shell-side medium inlets 2) are circumferentially opened in the upper part of the inner cylinder 1 to allow the liquid metal medium heated by the reactor core to enter the shell side. The outer cylinder 3 has a similar structure to the inner cylinder 1, and the inner cylinder 1 and outer cylinder 3 are arranged coaxially, forming a uniform annular space between them. This annular space is the channel for the shell-side fluid; the liquid metal medium pumped into the shell side flows through this space, which is also the area for arranging the spiral heat exchange tubes.

[0042] According to some embodiments of this application, multiple threaded tubes 4 are arranged in a staggered manner to form a tube bundle, and multiple tube bundles are combined in a radial distribution along an annular space to form a coil assembly. Each of the multiple threaded tubes 4 is connected to the tube inlet header 7 through multiple downcomers 9, and the upper end of each threaded tube 4 is connected to the tube outlet header 10.

[0043] In this embodiment, by setting multiple layers of tube bundles within the annular space, a large amount of heat exchange can be achieved with a small radial span, resulting in excellent heat exchange performance.

[0044] Figure 4 yes Figure 3 A magnified schematic diagram of a portion of the internal structure shown.

[0045] According to some embodiments of this application, such as Figure 4 As shown, the pool-type steam generator also includes a coil inlet connecting pipe 12. The two ends of the coil inlet connecting pipe 12 are connected to the tube inlet header 7 and the downcomer 9, respectively. The coil inlet connecting pipe 12 is used to guide the downcomer 9 to outside the area where the coil assembly is located, so that the downcomer 9 is isolated from the coil assembly.

[0046] According to some embodiments of this application, the pool-type steam generator further includes a coil outlet connection pipe 13, the two ends of which are respectively connected to the upper end of the tube outlet header 10 and the threaded pipe 4.

[0047] In this embodiment, the coil outlet connection pipe 13 is located at the bottom of the coil assembly. The coil outlet connection pipe 13 mainly realizes the reversal of the fluid. After the fluid (tube-side medium) inside the pipe is reversed, it spirals upward through the coil assembly (threaded pipe 4) and exchanges heat with the shell-side medium from top to bottom in a countercurrent manner during the spiral upward process.

[0048] According to some embodiments of this application, the coil outlet connecting pipe 13 is an S-shaped pipe. Multiple coil outlet connecting pipes 13 are arranged in a staggered annular configuration and connected to multiple threaded pipes 4 respectively.

[0049] According to some embodiments of this application, the pipe inlet header 7 is disposed above the upper orifice plate 5.

[0050] According to some embodiments of this application, the inlet header 7 forms a ring pipe with an arc of 180°, and the inlet pipe 8 is located in the middle of the ring pipe.

[0051] According to some embodiments of this application, the pipe outlet header 10 is disposed above the upper orifice plate 6.

[0052] According to some embodiments of this application, the tube outlet header 10 forms a ring pipe with an arc of 180°, and the steam outlet 11 is located in the middle of the ring pipe.

[0053] According to some embodiments of this application, the pool-type steam generator further includes a heat shield sleeve and end joints. The heat shield sleeve is fitted onto the downcomer 9, and the end joints are respectively disposed at both ends of the heat shield sleeve. The end joints are configured to form a sealed connection between the downcomer 9 and both ends of the heat shield sleeve. Inert gas is filled between the downcomer 9 and the heat shield sleeve to prevent the tube-side medium from being heated and vaporized during flow in the downcomer 9, thereby preventing backflow of bubbles.

[0054] According to some embodiments of this application, a throttling element 14 is provided between the downcomer and the inlet header of the tube side. The throttling element 14 is configured to regulate the flow rate of the inner tube side medium of the downcomer 9 by controlling the resistance.

[0055] In this embodiment, the throttling element 14 has various structural forms, such as spiral, gourd-shaped, or orifice plate, and various forms can be applied. The throttling element 14 mainly improves the flow instability between pipes by controlling resistance, so as to achieve a balanced flow distribution and good flow stability among the various threaded pipes. The lower end of the throttling element 14 is fixedly connected to the downcomer 9.

[0056] Figure 5 The diagram schematically shows a front view of the tube bundle support assembly of a pool-type steam generator according to an embodiment of this application.

[0057] According to some embodiments of this application, such as Figure 3 and Figure 5As shown, a tube bundle support assembly is also provided within the annular space. The tube bundle support assembly includes support bars 15 and fasteners 16. The support bars 15 are vertically arranged within the annular space, and their sides are provided with notches that match the threaded tubes, allowing the threaded tubes to be engaged in the notches. Two fasteners 16 are respectively located at the top and bottom of the annular space, and each fastener is connected to the support bar.

[0058] According to some embodiments of this application, there are multiple tube bundle support components, which are evenly spaced and arranged in an annular space.

[0059] According to some embodiments of this application, the pool-type steam generator also includes an upper cover plate 17, which has an annular structure. The outer edge of the upper cover plate 17 is sealed to the top of the outer cylinder 3, and the inner edge of the upper cover plate 17 is sealed to the top of the inner cylinder 1.

[0060] In this embodiment, the upper cover plate 17 is a large flat head with a straight section. The middle area corresponding to the reactor core is a hollow structure. The inner side of the upper cover plate 17 is welded to the top of the inner cylinder 1, and the outer side of the upper cover plate 17 is welded to the top of the outer cylinder 3.

[0061] The pool-type steam generator of this application embodiment has a large space in the middle area that can be used to arrange the reactor core and control rod drive mechanism, which is beneficial for use in pool-type reactors and is particularly suitable for manufacturing integrated reactors; the use of large-diameter threaded pipes requires only a small radial span to achieve a large heat exchange, resulting in good heat exchange effect; by setting throttling devices, the flow distribution between each threaded pipe is balanced, and the flow stability is good; the downcomer is a double-layered sleeve, which can ensure that the medium inside the pipe is not heated and bubble backflow during the descent.

[0062] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A pool-type steam generator, comprising: The inner cylinder forms a accommodating space suitable for placing the reactor core and shell-side medium. The upper part of the inner cylinder is provided with at least one shell-side medium inlet, which is suitable for introducing shell-side medium heated by the reactor core. The bottom of the inner cylinder is provided with a shell-side medium outlet, wherein the shell-side medium is liquid metal. An outer cylinder is fitted onto the inner cylinder, and an annular space is formed between the outer cylinder and the inner cylinder; Multiple spiral tubes are arranged within the annular space. Each spiral tube includes a tube-side medium inlet located at the bottom and a steam outlet located at the top. The tube-side medium flowing from bottom to top in the spiral tube exchanges heat with the shell-side medium in a countercurrent manner, turning into steam that flows out from the steam outlet. A pumping assembly is connected to the shell-side medium inlet, and the pumping assembly is adapted to pump the shell-side medium heated by the reactor core from the shell-side medium inlet into the annular space; A tube-side inlet header is located at the top of the annular space, and an inlet pipe is provided on the tube-side inlet header, which is suitable for introducing tube-side medium. Multiple downcomers, each downcomer having its upper end connected to the tube-side inlet header and its lower end connected to the tube-side medium inlet of the spiral tube; and A tube-side outlet header is disposed at the top of the annular space. The tube-side outlet header is connected to the upper end of the spiral tube, and the steam outlet is provided on the tube-side outlet header. The multiple spiral tubes are arranged in a staggered manner to form a tube bundle, and the multiple tube bundles are combined to form a coil assembly along the radial distribution of the annular space. The multiple spiral tubes are connected to the tube inlet header through multiple downcomers, and the upper end of each spiral tube is connected to the tube outlet header. The downcomer is isolated from the coil assembly; The pool-type steam generator also includes: A heat shield sleeve is fitted over the downcomer tube; and End connectors are respectively disposed at both ends of the heat shield sleeve, and the end connectors are configured to form a sealed connection with the downcomer at both ends of the heat shield sleeve; The space between the downcomer and the thermal shield is filled with an inert gas to prevent the tube-side medium from being heated and vaporized during flow in the downcomer, thus preventing the formation of backflow bubbles.

2. The pool-type steam generator according to claim 1 further includes: An upper orifice plate is disposed in the annular space. The upper orifice plate is provided with multiple input through holes. The upper orifice plate is located between the top of the spiral tube and the shell-side medium inlet. The upper orifice plate is configured to equalize the flow of the shell-side medium flowing into the shell-side medium inlet. as well as A lower orifice plate is disposed in the annular space. The lower orifice plate is located between the bottom of the spiral tube and the shell-side medium outlet. The lower orifice plate is provided with multiple output through holes suitable for uniformly outputting the shell-side medium, so as to return the shell-side medium that has completed countercurrent heat exchange to the inner cylinder for reheating.

3. The pool-type steam generator according to claim 2 further includes: The coil inlet connecting pipe is connected at both ends to the tube inlet header and the downcomer, respectively. The coil inlet connecting pipe is used to guide the downcomer to outside the area where the coil assembly is located, so that the downcomer is isolated from the coil assembly.

4. The pool-type steam generator according to claim 2 further includes: The coil outlet connecting pipe is connected at both ends to the outlet header of the tube side and the upper end of the spiral tube, respectively.

5. The pool-type steam generator according to claim 2, wherein, The pipe inlet header is located above the upper orifice plate.

6. The pool-type steam generator according to claim 5, wherein, The inlet header of the pipe side forms a ring pipe with an arc of 180°, and the inlet pipe is located in the middle of the ring pipe.

7. The pool-type steam generator according to claim 2, wherein, The pipe outlet header is located above the upper orifice plate.

8. The pool-type steam generator according to claim 7, wherein, The outlet header of the tube side forms a ring pipe with an arc of 180°, and the steam outlet is located in the middle of the ring pipe.

9. The pool-type steam generator according to claim 2, wherein, A connection is provided between the downcomer and the tube-side inlet header: A throttling device is configured to regulate the flow rate of the medium in the downcomer by controlling resistance.

10. The pool-type steam generator according to claim 2, wherein, A tube bundle support assembly is also provided within the annular space, the tube bundle support assembly comprising: A support bar, vertically arranged within the annular space, has notches spaced along its sides that match the spiral tube, allowing the spiral tube to be engaged within these notches; and Two fasteners are respectively located at the top and bottom of the annular space, and the two fasteners are respectively connected to the support bar.

11. The pool-type steam generator according to claim 10, wherein, The number of tube bundle support components is multiple, and the multiple tube bundle support components are evenly spaced within the annular space.

12. The pool-type steam generator according to claim 1, further comprising: The upper cover plate has a ring structure. The outer edge of the upper cover plate is sealed to the top of the outer cylinder, and the inner edge of the upper cover plate is sealed to the top of the inner cylinder.

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