High temperature gas cooled reactor class supercritical ultra supercritical boiler steam generator

Abstract

The application provides a high-temperature gas cooled reactor type supercritical ultra-supercritical boiler steam generator, which comprises a shell and a heat exchange device arranged in the shell, a maintenance space for people to enter is arranged between the shell and the heat exchange device, the shell is provided with a hot helium gas inlet and a cold helium gas outlet connected with a reactor, and the application further comprises a helium gas isolation valve for opening and closing the hot helium gas inlet and the cold helium gas outlet. In this way, since the helium gas isolation valve can close the hot helium gas inlet and the cold helium gas outlet, the helium gas passage with the reactor can be cut off in an accident, and the supply of high-temperature helium gas is stopped, so that the safety level of the steam generator is reduced, the steam generator is no longer limited by the nuclear power safety I level design and manufacturing specification, and the thermal power boiler design and manufacturing specification can be used. Moreover, the helium gas cannot be activated, the radiation dose inside the boiler steam generator is very low, and personnel can enter the maintenance space to check and maintain the boiler steam generator.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat exchangers, in particular to a high-temperature gas cooled reactor type supercritical ultra-supercritical boiler steam generator. BACKGROUND

[0002] The existing pressurized water reactor steam generator is generally a reverse U-shaped tube natural circulation steam generator, as shown in FIG. 1, the length of the reverse U-shaped tube is 24 meters, all the reverse U-shaped tube bundles 100 are installed on a single tube plate, and the gap between the reverse U-shaped tube bundle 100 and the container shell 300 is very small. Figure 1

[0003] The existing high-temperature gas cooled reactor steam generator generally adopts a spiral tube type, as shown in FIG. 2, a single spiral tube is very long, generally more than 60 meters, and the number of spiral tubes is large, which can reach several hundred. Similar to the existing pressurized water reactor steam generator, the gap between the spiral tube bundle 200 and the container shell 300 is very small. Figure 2

[0004] However, due to the limited space between the tube bundle arrangement and the container shell of the existing steam generator, personnel cannot enter the pressure-containing shell, and it is difficult to realize manual in-service inspection and maintenance.

[0005] Therefore, how to solve the problem that the steam generator in the prior art has a high safety level, the space between the tube bundle arrangement and the container shell is limited, the space in the pressure-containing shell is not accessible to personnel, and manual in-service inspection and maintenance are difficult to realize, becomes an important technical problem to be solved by the person skilled in the art. SUMMARY

[0006] The purpose of the present application is to provide a high-temperature gas cooled reactor type supercritical ultra-supercritical boiler steam generator, which solves the problem that the steam generator in the prior art has a high safety level, the space between the tube bundle arrangement and the container shell is limited, the space in the pressure-containing shell is not accessible to personnel, and manual in-service inspection and maintenance are difficult to realize.

[0007] The present application provides a high-temperature gas cooled reactor type supercritical ultra-supercritical boiler steam generator, comprising:

[0008] a shell and a heat exchange device arranged in the shell, a maintenance space for personnel to enter is provided between the shell and the heat exchange device, and the shell is provided with a hot helium inlet and a cold helium outlet connected with a reactor;

[0009] a helium isolation valve for opening and closing the hot helium inlet and the cold helium outlet.

[0010] ​​The high-temperature gas cooled reactor type supercritical ultra-supercritical boiler steam generator provided by the application has a shell which is a prestressed concrete shell or a steel shell.

[0011] The inner wall of the prestressed concrete shell is provided with a first heat preservation layer.

[0012] The distance between the shell and the heat exchange device is greater than or equal to 0.6 meters.

[0013] The heat exchange device comprises:

[0014] The preheater, the evaporator and the superheater are arranged in the horizontal direction and are sequentially and spacedly arranged in the vertical direction.

[0015] The main water feeding pipe is connected with the inlet of the preheater at one end and penetrates through the shell at the other end.

[0016] The first connecting assembly is connected between the outlet of the preheater and the inlet of the evaporator and between the outlet of the evaporator and the inlet of the superheater.

[0017] The main steam pipe is connected with the outlet of the superheater at one end and penetrates through the shell at the other end.

[0018] The superheater is at least two and is sequentially and spacedly arranged in the vertical direction, and the adjacent two superheaters are connected through the first connecting assembly.

[0019] The heat exchange device further comprises:

[0020] The reheater is arranged in the horizontal direction and is located below the superheater.

[0021] The reheated steam inlet pipe is connected with the inlet of the reheater at one end and penetrates through the shell at the other end.

[0022] The reheated steam outlet pipe is connected with the outlet of the reheater at one end and penetrates through the shell at the other end.

[0023] The reheater is at least two and is alternately arranged with the superheater in the vertical direction,

[0024] The heat exchange device further comprises a second connecting assembly, and two adjacent reheaters are connected through the second connecting assembly.

[0025] The high-temperature gas cooled reactor type supercritical ultra-supercritical boiler steam generator provided by the application further comprises:

[0026] A helium flow channel enclosing plate is arranged around the circumference of the heat exchange device, and one end of the helium flow channel enclosing plate is in communication with the hot helium inlet;

[0027] A cold helium outlet is in communication with the other end of the helium flow channel enclosing plate.

[0028] The high-temperature gas cooled reactor type supercritical ultra-supercritical boiler steam generator provided by the application, the shell is a steel shell, and an inner wall of the helium flow channel enclosing plate is provided with a second thermal insulation layer.

[0029] The high-temperature gas cooled reactor type supercritical ultra-supercritical boiler steam generator provided by the application comprises a shell and a heat exchange device arranged in the shell, a maintenance space for personnel is arranged between the shell and the heat exchange device, the shell is provided with a hot helium inlet and a cold helium outlet connected with a reactor, and further comprises a helium isolation valve for opening and closing the hot helium inlet and the cold helium outlet. In this way, since the helium isolation valve can close the hot helium inlet and the cold helium outlet, the helium passage with the reactor can be cut off in an accident, and the supply of high-temperature helium is stopped, so that the safety level of the steam generator is reduced, and the steam generator is no longer limited by the nuclear power safety I-level design and manufacturing specification, and can use the thermal power boiler design and manufacturing specification. Moreover, the helium cannot be activated, and the irradiation dose inside the boiler steam generator is very low, so that personnel can enter the maintenance space to check and maintain the boiler steam generator, and the problem that the safety level of the steam generator in the prior art is high, the space between the tube bundle arrangement and the container shell is limited, and personnel cannot access the space in the pressure-containing shell, and manual in-service maintenance is difficult to realize is solved. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the application or prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative effort.

[0031] Figure 1 is a structural schematic diagram of a pressurized water reactor steam generator in the prior art;

[0032] Figure 2 is a structural schematic diagram of a high-temperature gas cooled reactor steam generator in the prior art;

[0033] Figure 3is a longitudinal sectional view of a high-temperature gas cooled reactor type supercritical ultra supercritical boiler steam generator according to an embodiment of the present application;

[0034] Figure 4 is a transverse sectional view of a high-temperature gas cooled reactor type supercritical ultra supercritical boiler steam generator according to an embodiment of the present application;

[0035] Figure 5 is a longitudinal sectional view of a high-temperature gas cooled reactor type supercritical ultra supercritical boiler steam generator according to another embodiment of the present application;

[0036] Figure 6 is a transverse sectional view of a high-temperature gas cooled reactor type supercritical ultra supercritical boiler steam generator according to another embodiment of the present application;

[0037] Reference numerals:

[0038] 100: inverted U-shaped tube bundle; 200: spiral tube bundle; 300: vessel shell;

[0039] 1: main feedwater pipe; 2: first header; 3: preheater;

[0040] 4: first connecting pipe; 5: evaporator; 6: first superheater;

[0041] 7: first reheater; 8: second superheater; 9: second reheater;

[0042] 10: third superheater; 11: main steam pipe; 12: hot helium inlet;

[0043] 13: helium flow channel coaming; 14: reheated steam outlet pipe; 15: second header;

[0044] 16: second connecting pipe; 17: reheated steam inlet pipe; 18: pre-stressed concrete shell;

[0045] 19: first thermal insulation layer; 20: cold helium outlet; 21: steel shell;

[0046] 22: maintenance space; 23: heat exchange device; 24: second thermal insulation layer;

[0047] 25: helium isolation valve; 26: reactor. DETAILED DESCRIPTION

[0048] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be clearly and completely described below with reference to the drawings in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0049] The present application will be described below with reference to the drawings. Figures 3 to 6 The present application provides a high-temperature gas cooled reactor type supercritical ultra-supercritical boiler steam generator.

[0050] The present application provides a high-temperature gas cooled reactor type supercritical ultra-supercritical boiler steam generator, which comprises a shell, a heat exchange device 23 and a helium isolation valve 25. Specifically, the shell is provided with a hot helium inlet 12 and a cold helium outlet 20 connected with a reactor 26, the heat exchange device 23 is arranged in the shell, a maintenance space 22 for personnel access is arranged between the shell and the heat exchange device 23, and the helium isolation valve 25 is used to open and close the hot helium inlet 12 and the cold helium outlet 20. The high-temperature helium generated by the reactor 26 is introduced into the supercritical ultra-supercritical boiler through the hot helium inlet 12, and exchanges heat with the heat exchange medium in the heat exchange device 23 to generate high-temperature and high-pressure steam, which is used to drive a steam turbine to generate electricity. Generally, water is used as the heat exchange medium. The high-temperature helium becomes low-temperature helium after heat exchange, and then returns to the reactor 26 through the cold helium outlet 20. As shown in Figure 4 and Figure 6 As can be seen from the cross-sectional schematic view of the high-temperature gas cooled reactor type supercritical ultra-supercritical boiler steam generator, the cross section of the shell is circular, and the cross section of the heat exchange region formed by the heat exchange device 23 is rectangular. The maintenance space 22 of the boiler is arranged between the shell and the heat exchange device 23 for maintenance personnel to enter to check or replace the heat exchange device 23 and the like. The helium isolation valve 25 is arranged on the pipeline connected with the hot helium inlet 12 and the cold helium outlet 20, and the hot helium inlet 12 and the cold helium outlet 20 can be closed to stop the introduction of high-temperature helium during maintenance. By reasonably arranging the helium isolation valve 25, the safety level of the original steam generator is reduced to meet the design and manufacturing specifications of the thermal power supercritical ultra-supercritical boiler. In this way, the design difficulty of the safety I class equipment is reduced, and the mature experience in the selection of materials, design, construction, operation and maintenance of the thermal power supercritical ultra-supercritical boiler can be fully learned, thereby reducing the design and manufacturing difficulty of the supercritical ultra-supercritical steam generator and achieving the goal of easy maintenance.

[0051] Thus, since the helium isolation valve 25 can close the hot helium inlet 12 and the cold helium outlet 20, the helium passage with the reactor can be cut off in an accident, and the supply of high-temperature helium is stopped, thereby reducing the safety level of the steam generator, which is no longer limited by the nuclear power safety I-level design and manufacturing specifications, and can use the thermal power boiler design and manufacturing specifications. Moreover, the helium cannot be activated, and the internal irradiation dose of the boiler steam generator is very low, allowing personnel to enter the inspection space 22 to check and maintain the boiler steam generator, thereby solving the problem in the prior art that the steam generator has a high safety level, the space between the tube bundle and the container shell is limited, the space in the pressure-containing shell is inaccessible to personnel, and manual in-service inspection is difficult to implement.

[0052] In the embodiment of the present application, the shell can be designed as a prestressed concrete shell 18 or a steel shell 21. Since the safety level of the device is reduced, the steam generator in the original nuclear island is changed to a thermal power supercritical or ultra-supercritical tower-type boiler, and therefore the material used for the thermal power supercritical or ultra-supercritical boiler can be used as the pressure-containing container of the primary-side helium, so that the space in the pressure-containing container is large, and a large space is left between the pressure-containing container and the heat transfer tube bundle area, allowing personnel to enter the shell for in-service inspection and maintenance.

[0053] In the embodiment of the present application, as shown in Figure 3 The inner wall of the prestressed concrete shell 18 is provided with a first thermal insulation layer 19. Since the working temperature of the prestressed concrete is generally lower than 65℃, in order to ensure that the temperature of the concrete does not exceed the temperature, it is necessary to lay a thermal insulation layer on the inner surface of the prestressed concrete shell 18 to reduce the temperature of the concrete, so as to ensure the reliable and safe operation of the device.

[0054] In the embodiment of the present application, the distance between the shell and the heat exchange device 23 is greater than or equal to 0.6 meters. In this way, sufficient space is reserved for workers to enter, facilitating maintenance, repair, and arrangement of the heat exchange device 23, etc.

[0055] In the embodiment of the present application, the heat exchange device 23 comprises a preheater 3, an evaporator 5, a superheater, a main feedwater pipe 1, a first connecting assembly and a main steam pipe 11. Specifically, the heat transfer tube bundles of the preheater 3, the evaporator 5 and the superheater are arranged in a horizontal direction, and the preheater 3, the evaporator 5 and the superheater are sequentially and spacedly arranged in a vertical direction, which is beneficial to arranging the pipelines on the side. One end of the main feedwater pipe 1 is connected with the inlet of the preheater 3, and the other end penetrates through the shell to be connected with an external water inlet pipeline. The first connecting assembly is connected between the outlet of the preheater 3 and the inlet of the evaporator 5, and between the outlet of the evaporator 5 and the inlet of the superheater. One end of the main steam pipe 11 is connected with the outlet of the superheater, and the other end penetrates through the shell to be connected with an external steam output pipeline. Specifically, the first connecting assembly comprises first headers 2 and first connecting pipes 4, and the inlets and outlets of the preheater 3, the evaporator 5 and the superheater are all provided with the first headers 2, and two adjacent first headers 2 are connected through the first connecting pipes 4. Moreover, the main feedwater pipe 1 is connected with the first header 2 at the inlet of the preheater 3, and the main steam pipe 11 is connected with the first header 2 at the outlet of the superheater. In addition, the main feedwater pipe 1, the first headers 2, the first connecting pipes 4 and the main steam pipe 11 are arranged in the maintenance space 22, which is beneficial to the maintenance and repair operation of the heat transfer tubes. It should be noted that, as shown in the high-temperature gas cooled reactor type supercritical ultra-supercritical boiler steam generator in the figures, the upper and lower directions in the figures are the horizontal directions, and the left and right directions in the figures are the vertical directions. Figure 3 and Figure 5 As shown in the placement position of the high-temperature gas cooled reactor type supercritical ultra-supercritical boiler steam generator, the upper and lower directions in the figures are the horizontal directions, and the left and right directions in the figures are the vertical directions.

[0056] In this way, compared with the existing inverted U-shaped tube bundle and spiral tube bundle type steam generator, the embodiment of the present application adopts a horizontal tube bundle arrangement, and the inner volume of the primary side pressure-bearing container is large, and the preheater 3, the superheater and the like can be additionally arranged, so that the water working medium is fully heat exchanged to generate superheated steam, and the parameters of the steam medium are improved, so that the steam parameters reach the quality of supercritical and ultra-supercritical, thereby improving the power generation efficiency of the entire power generation system.

[0057] Moreover, the heat transfer tubes of the preheater 3, the evaporator 5 and the superheater are collected in the headers, and the water working medium is sent to the header of the next heat exchanger after being collected, so that the temperature uniformity and flow stability and the like can be well guaranteed. Compared with the structure in which the inverted U-shaped tube bundle is connected with only a single tube plate, the tube bundle arrangement of the heat exchange device 23 in the embodiment of the present application adopts multiple headers arranged in the vertical direction, thereby reducing the length of each heat transfer tube, which is beneficial to the processing and manufacturing, and the maintenance and inspection, and is beneficial to the steam mixing and the stability of the two-phase flow.

[0058] In addition, since the safety level of the device is reduced, the heat transfer tube of the high-temperature gas cooled reactor non-nuclear level steam generator in the embodiment of the application has relatively low cost, reduced processing difficulty, and is easy to set the tube plate and the through-shell structure, so as to realize the main feed water pipe 1 and the main steam pipe 11 penetrating the shell.

[0059] In the embodiment of the application, the superheater is at least two and is sequentially and spacedly arranged in the vertical direction, and the adjacent two superheaters are connected through the first connecting assembly. The number of the superheaters can be determined according to the actual design requirements. For example, the superheater is provided as three, including the first superheater 6, the second superheater 8 and the third superheater 10 sequentially arranged in the vertical direction, and the inlet and outlet of each superheater are provided with the first header 2, and the adjacent two first headers 2 are connected through the first connecting pipe 4. The secondary side feed water enters the preheater 3 through the main feed water pipe 1 and the first header 2, and then sequentially passes through the evaporator 5, the first superheater 6, the second superheater 8 and the third superheater 10 to absorb heat and generate superheated steam, and finally flows out through the main steam pipe 11 to the steam turbine for power generation. In this way, the parameters of the steam medium are significantly improved, thereby reducing the investment cost per unit of power generation.

[0060] In the embodiment of the application, the heat exchange device 23 further comprises a reheater, a reheated steam inlet pipe 17 and a reheated steam outlet pipe 14. Specifically, the heat transfer tube bundle of the reheater is arranged in the horizontal direction and is located below the superheater. One end of the reheated steam inlet pipe 17 is connected with the inlet of the reheater, and the other end penetrates the shell and is used for connecting the secondary side reheated steam pipe from the steam turbine to reheat the wet steam. One end of the reheated steam outlet pipe 14 is connected with the outlet of the reheater, and the other end penetrates the shell and is used for connecting the reheated steam pipe flowing to the steam turbine, so that the reheated steam goes to the steam turbine for continuous power generation. In this way, the wet steam flowing out of the steam turbine can be reheated, the utilization rate of the reheated steam is improved, the heat exchange efficiency is fully improved, and the power generation efficiency of the whole system is improved. The heat exchangers such as the preheater 3, the evaporator 5, the superheater and the reheater can be reasonably arranged in the vertical direction according to their heat absorption temperature and power. These heat exchangers can use U-shaped tubes or serpentine tubes as heat transfer tubes to ensure the number of heat exchange areas per unit volume and reduce the manufacturing and processing cost. Of course, other types of tube bundles selected by the thermal power boiler can also be used as heat transfer tubes.

[0061] In the embodiment of the present application, the reheater is at least two and is arranged alternately with the superheater in the vertical direction. The number of reheaters can be determined according to actual design requirements. The heat exchange device 23 further comprises a second connecting assembly, and two adjacent reheaters are connected through the second connecting assembly. For example, the reheater is provided as two, comprising a first reheater 7 and a second reheater 9 arranged in sequence in the vertical direction, and being arranged alternately with the first superheater 6, the second superheater 8 and the third superheater 10 in sequence. The second connecting assembly comprises a second header 15 and a second connecting pipe 16, and the inlet and outlet of the first reheater 7 and the second reheater 9 are provided with the second header 15, and two adjacent second headers 15 are connected through the second connecting pipe 16. The reheated steam inlet pipe 17 is connected with the second header 15 of the inlet of the first reheater 7, and the reheated steam outlet pipe 14 is connected with the second header 15 of the outlet of the second reheater 9. The secondary side reheated steam from the steam turbine enters the first reheater 7 and the second reheater 9 through the reheated steam inlet pipe 17, absorbs heat, is reheated, and then goes to the steam turbine again through the reheated steam outlet pipe 14 to continue power generation. In addition, the reheated steam inlet pipe 17, the second header 15, the second connecting pipe 16 and the reheated steam outlet pipe 14 are arranged in the maintenance space 22, which is convenient for the maintenance and repair operation of the heat transfer pipe.

[0062] In the embodiment of the present application, the high-temperature gas cooled reactor type supercritical ultra-supercritical boiler steam generator further comprises a helium flow channel enclosing plate 13, which is arranged around the periphery of the heat exchange device 23 to form a channel for the flow of helium. One end of the helium flow channel enclosing plate 13 is in communication with the hot helium inlet 12, and the other end is in communication with the cold helium outlet 20. The high-temperature helium enters the channel formed by the helium flow channel enclosing plate 13 from the bottom hot helium inlet 12, flows from bottom to top, fully exchanges heat with the countercurrently flowing water working medium, releases heat, forms low-temperature helium, and then flows out of the shell from the cold helium outlet 20. In this way, the high-temperature helium can fully contact with the water working medium in the internal space of the helium flow channel enclosing plate 13, ensuring the heat exchange efficiency.

[0063] Further, when the shell is a steel shell 21, a second heat preservation layer 24 can also be applied to the inner wall of the helium flow channel enclosing plate 13, which can reduce the heat exchange between the hot and cold helium inside and outside the helium flow channel enclosing plate 13. The working temperature of the steel shell 21 can reach 250℃, so the cold helium can be used to cool the steel shell 21 to keep it at a normal working temperature.

[0064] In the following, different embodiments provided by the present application will be specifically described in combination with the above content.

[0065] Embodiment one

[0066] Reference Figure 3 and Figure 4The embodiment of the present application provides a high-temperature gas cooled reactor type supercritical ultra-supercritical boiler steam generator, which comprises a shell and a heat exchange device 23 in the shell. The shell is a prestressed concrete shell 18, which is a pressure-bearing container of primary side helium gas and is used for pressure bearing of high-pressure helium gas working medium. The inner wall of the shell is provided with a first heat preservation layer 19 for reducing the temperature of the concrete, the bottom is provided with a hot helium gas inlet 12, and the top is provided with a cold helium gas outlet 20. A helium gas flow channel surrounding plate 13 is circumferentially arranged around the heat exchange device 23 to form a helium gas flow channel, and the lower end of the helium gas flow channel surrounding plate 13 is communicated with the hot helium gas inlet 12, and the upper end is communicated with the cold helium gas outlet 20. The primary side high-temperature helium gas enters the pressure-bearing container shell side from the hot helium gas inlet 12, flows through the heat exchange device 23 from the lower end to the upper end along the flow channel formed by the helium gas flow channel surrounding plate 13, and transfers heat to the secondary side feed water to form low-temperature helium gas, and then flows out through the cold helium gas outlet 20.

[0067] The heat exchange device 23 is a pressure-bearing container of secondary side water working medium, which comprises a preheater 3, an evaporator 5, a first superheater 6, a second superheater 8 and a third superheater 10 arranged in sequence from top to bottom, and the inlet and outlet of each heat exchanger are provided with a first header 2, and the first headers 2 are connected through a first connecting pipe 4. The secondary side feed water enters the preheater 3 through the main feed water pipeline 1 and the first header 2, and then sequentially passes through the evaporator 5, the first superheater 6, the second superheater 8 and the third superheater 10 to absorb heat and generate superheated steam, and finally flows out through the main steam pipeline 11 to go to the steam turbine for power generation.

[0068] The heat exchange device 23 further comprises a first reheater 7 and a second reheater 9 arranged in sequence in the vertical direction, the first reheater 7 is arranged between the first superheater 6 and the second superheater 8, and the second reheater 9 is arranged between the second superheater 8 and the third superheater 10. The inlet and outlet of each reheater are provided with a second header 15, and the second headers 15 are connected through a second connecting pipe 16. The secondary side reheated steam from the steam turbine enters the first reheater 7 and the second reheater 9 through the reheated steam inlet pipeline 17, absorbs heat and is reheated, and then goes to the steam turbine again through the reheated steam outlet pipeline 14 to continue power generation.

[0069] There is a large space between the shell and the heat exchange device 23 to form an inspection space 22 for people to enter, and the distance between the shell and the heat exchange device 23 is not less than 0.6 meters, so that the heat exchangers can be easily inspected and maintained. The headers and the connecting pipes are arranged outside the helium gas flow channel surrounding plate 13 and in the shell, which is convenient for maintenance operation. Only the main feed water pipeline 1, the main steam pipeline 11, the reheated steam inlet pipeline 17 and the reheated steam outlet pipeline 14 penetrate the shell, which is beneficial to the manufacture and safety of the pressure-bearing container. The heat exchanger tube bundles are arranged horizontally, so that the inlets and outlets can be arranged at different heights, thereby facilitating the arrangement of superheaters and reheaters in the vertical direction.

[0070] The helium isolation valve 25 can open and close the hot helium inlet 12 and the cold helium outlet 20, and when the maintenance is closed, the maintenance personnel can enter the shell. Thus, the safety level of the steam generator is reduced, the materials, design and manufacturing specifications used by the supercritical and ultra-supercritical boiler of the thermal power can be used, and the personnel can enter the pressure vessel to perform in-service inspection and maintenance.

[0071] Embodiment two

[0072] Reference Figure 5 and Figure 6 The difference from the first embodiment is that the shell is a steel shell 21. The hot helium inlet 12 and the cold helium outlet 20 are arranged at the bottom of the shell, and the cold helium outlet 20 is arranged around the circumference of the hot helium inlet 12. The lower end of the helium flow channel coaming 13 is communicated with the hot helium inlet 12, and the upper end is open, and finally communicated with the cold helium outlet 20. The inner wall of the helium flow channel coaming 13 is provided with a second heat preservation layer 24 to isolate the cold and hot helium inside and outside the helium flow channel coaming 13. The primary side high-temperature helium enters the pressure vessel shell side from the hot helium inlet 12, flows along the flow channel formed by the helium flow channel coaming 13 from bottom to top, and passes through the heat exchange device 23 to transfer heat to the secondary side feed water, forms low-temperature helium, and then enters the maintenance space 22 and flows out from the cold helium outlet 20 from top to bottom.

[0073] In summary, the application provides a high-temperature gas cooled reactor type supercritical and ultra-supercritical boiler steam generator, which can reduce the safety level of the steam generator, use the materials, design and manufacturing specifications used by the supercritical and ultra-supercritical boiler of the thermal power, and fully utilize the supercritical and ultra-supercritical thermal power technology to replace the steam generator in the nuclear island, so as to avoid the design, manufacturing and maintenance difficulties of the safety I class supercritical and ultra-supercritical steam generator, reduce the technical difficulty of the whole system, and improve the power generation efficiency of the whole system.

[0074] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the application.

Claims

1. A high-temperature gas-cooled reactor class supercritical ultra-supercritical boiler steam generator, characterized by, The utility model relates to a helium gas heat exchanger, comprising: a shell and a heat exchange device arranged in the shell, a maintenance space for human access being provided between the shell and the heat exchange device, the shell being provided with a hot helium gas inlet connected with a reactor and a cold helium gas outlet; a helium gas isolation valve for opening and closing the hot helium gas inlet and the cold helium gas outlet; the heat exchange device comprises: a preheater, an evaporator and a superheater arranged in a horizontal direction, and the preheater, the evaporator and the superheater being sequentially and spacedly arranged in a vertical direction; a main feedwater pipe, one end of which is connected with an inlet of the preheater and the other end of which penetrates through the shell; a first connecting assembly connected between an outlet of the preheater and an inlet of the evaporator and between an outlet of the evaporator and an inlet of the superheater; a main steam pipe, one end of which is connected with an outlet of the superheater and the other end of which penetrates through the shell; the heat exchange device further comprises: a reheater arranged in a horizontal direction and located below the superheater; a reheated steam inlet pipe, one end of which is connected with an inlet of the reheater and the other end of which penetrates through the shell; a reheated steam outlet pipe, one end of which is connected with an outlet of the reheater and the other end of which penetrates through the shell.

2. The supercritical once-through boiler steam generator of the type of a high- temperature gas-cooled reactor according to claim 1, characterized in that, The shell is a prestressed concrete shell or a steel shell.

3. The steam generator of a high temperature gas cooled reactor class supercritical ultra supercritical boiler according to claim 2, characterized in that, An inner wall of the prestressed concrete shell is provided with a first thermal insulation layer.

4. The steam generator of a supercritical or ultra- supercritical boiler of a high- temperature gas-cooled reactor according to claim 1, characterized by, A distance between the shell and the heat exchange device is greater than or equal to 0.6 meters.

5. The steam generator of a supercritical or ultra- supercritical boiler of a high- temperature gas-cooled reactor according to claim 4, characterized by The superheater is at least two, and is sequentially and spacedly arranged in a vertical direction, and adjacent two superheaters are connected through the first connecting assembly.

6. The steam generator of a high temperature gas cooled reactor type supercritical ultra supercritical boiler as claimed in claim 5, wherein, The reheater is at least two, and is alternately arranged with the superheater in a vertical direction, the heat exchange device further comprises a second connecting assembly, and adjacent two reheaters are connected through the second connecting assembly.

7. The supercritical once-through boiler steam generator of claim 1, wherein, Further comprising: a helium gas flow channel enclosing plate, which is arranged around a circumference of the heat exchange device, one end of the helium gas flow channel enclosing plate being in communication with the hot helium gas inlet; a cold helium gas outlet in communication with the other end of the helium gas flow channel enclosing plate.

8. The steam generator of a supercritical or ultra- supercritical boiler of a high- temperature gas-cooled reactor according to claim 7, characterized in that, The shell is a steel shell, and an inner wall of the helium gas flow channel enclosing plate is provided with a second thermal insulation layer.

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