A method for disassembling and assembling a hot gas duct for maintenance of a high-temperature gas-cooled reactor nuclear power plant

Abstract

The embodiment of the present application discloses a method for disassembling and assembling a hot gas duct for maintenance of a high-temperature gas-cooled reactor nuclear power plant. During disassembly and assembly, first, the connection between the fourth hot gas duct section and the third hot gas duct section, as well as the connection between the steam generator and the hot gas duct housing, is released, and the steam generator is moved away from the reactor pressure vessel to provide space for the disassembly of the hot gas duct. Secondly, the fourth hot gas duct section is translated with the steam generator, the third hot gas duct section is disassembled and assembled within the operation space vacated after the steam generator is displaced, the hot gas duct housing and the second hot gas duct section are lifted and lowered synchronously, and the first hot gas duct section is disassembled and assembled within the space vacated by the overall downward movement of the hot gas duct housing and the second hot gas duct section. According to the length characteristics of each structure of the hot gas duct, the disassembly and assembly steps are reasonably arranged to create conditions for the replacement of the hot gas duct sealing ring, the inspection of the connection bolts of each section, and other maintenance work.

Description

Technical Field

[0001] This application relates to the field of nuclear power technology, and particularly relates to a disassembly and assembly method for maintaining a hot gas duct in a high-temperature gas-cooled reactor nuclear power plant. Background Art

[0002] The primary circuit compartments of the concrete structure of a high-temperature gas-cooled reactor include a reactor compartment and a steam generator compartment. Inside the primary circuit compartments, a reactor pressure vessel, a hot gas duct, a hot gas duct housing, and a steam generator are installed. The equipment disassembly and assembly work carried out for maintaining the hot gas duct is mainly carried out inside the steam generator compartment.

[0003] Due to the limited internal space of the steam generator compartment of the high-temperature gas-cooled reactor and the complex process of the equipment disassembly and assembly work carried out for maintaining the hot gas duct, it is difficult to carry out the replacement of the sealing ring of the hot gas duct, the inspection of the connecting bolts, and other maintenance work.

[0004] Therefore, clarifying the disassembly and assembly method for maintaining the hot gas duct in a high-temperature gas-cooled reactor nuclear power plant to ensure the smooth progress of the sealing ring replacement, the inspection of the connecting bolts, and other maintenance work has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0005] This application proposes a disassembly and assembly method for maintaining a hot gas duct in a high-temperature gas-cooled reactor nuclear power plant to ensure the smooth progress of the sealing ring replacement, the inspection of the connecting bolts, and other maintenance work.

[0006] To achieve the above object, this application provides a disassembly and assembly method for maintaining a hot gas duct in a high-temperature gas-cooled reactor nuclear power plant, including the steps of:

[0007] 1) Remove the cold helium lift pipe and elbow inside the steam generator, and remove the main steam detachable pipe section and the main feed water detachable pipe section connected to the steam generator;

[0008] 2) Disconnect the fourth hot gas duct section from the third hot gas duct section, and disconnect the steam generator from the hot gas duct housing, and move the steam generator away from the reactor pressure vessel;

[0009] 3) Disconnect the third hot gas duct section from the second hot gas duct section;

[0010] 4) Disconnect the hot gas duct housing from the reactor pressure vessel, and move the hot gas duct housing towards the steam generator;

[0011] 5) Disconnect the second hot gas duct section from the first hot gas duct section, and move the whole formed by the second hot gas duct section and the hot gas duct housing downward, and the whole formed by the second hot gas duct section and the hot gas duct housing is arranged in a dislocation manner relative to the first hot gas duct section;

[0012] 6) Disconnect the first hot gas duct section from the reactor vessel head, and remove the first hot gas duct section from the hot gas duct nozzle flange of the reactor pressure vessel;

[0013] 7) Connect the first hot gas duct section and the reactor vessel head;

[0014] 8) Move the assembly composed of the second hot gas duct section and the hot gas duct housing upward, connect the first hot gas duct section and the second hot gas duct section, and at the same time connect the hot gas duct housing and the reactor pressure vessel;

[0015] 9) Connect the second hot gas duct section and the third hot gas duct section;

[0016] 10) Move the steam generator towards the reactor pressure vessel, connect the steam generator and the hot gas duct housing, and connect the fourth hot gas duct section and the third hot gas duct section;

[0017] 11) Connect the steam generator with the cold helium riser and elbow, and connect the steam generator with the main steam removable pipe section and the main feed water removable pipe section;

[0018] Wherein, in step 3) or step 9), replace the first sealing ring between the third hot gas duct section and the second hot gas duct section, and / or repair the first connecting bolt between the third hot gas duct section and the second hot gas duct section;

[0019] In step 5) or step 8), replace the second sealing ring between the second hot gas duct section and the first hot gas duct section, and / or repair the third connecting bolt between the second hot gas duct section and the first hot gas duct section;

[0020] In step 6), replace the third sealing ring between the first hot gas duct section and the reactor vessel head, and / or repair the fourth connecting bolt between the third hot gas duct and the reactor vessel head;

[0021] In step 2) or step 10), replace the fourth sealing ring between the fourth hot gas duct section and the third hot gas duct section, and / or repair the fifth connecting bolt between the fourth hot gas duct section and the third hot gas duct section.

[0022] Preferably, in the above disassembly and assembly method for maintaining the hot gas duct of a high-temperature gas-cooled reactor nuclear power plant, before disconnecting the second hot gas duct section from the first hot gas duct section in step 5), the following steps are further included:

[0023] Move the hot gas duct housing towards the steam generator, disconnect the first branch duct section and the second branch duct section inside the second hot gas duct section, and replace the fifth sealing ring between the first branch duct section and the second branch duct section;

[0024] Connect the first branch duct section and the second branch duct section to reconstitute the second hot gas duct section;

[0025] Fix the second hot gas duct section in the hot gas duct housing.

[0026] Preferably, in the above method for disassembling and assembling the hot gas duct for maintenance of a high-temperature gas-cooled reactor nuclear power plant, after moving the whole formed by the second hot gas duct section and the hot gas duct housing downward in step 5), or before moving the whole formed by the second hot gas duct section and the hot gas duct housing upward in step 8), the method further includes the steps:

[0027] Move the hot gas duct housing towards the steam generator or the reactor pressure vessel;

[0028] Disconnect the first branch duct section and the second branch duct section inside the second hot gas duct section, and replace the fifth sealing ring;

[0029] Connect the first branch duct section and the second branch duct section to reconstitute the second hot gas duct section;

[0030] Fix the second hot gas duct section in the hot gas duct housing.

[0031] Preferably, in the above method for disassembling and assembling the hot gas duct for maintenance of a high-temperature gas-cooled reactor nuclear power plant, step 3) further includes:

[0032] Place the third hot gas duct section in the hot gas duct nozzle flange of the steam generator or temporarily connect the third hot gas duct section and the fourth hot gas duct section.

[0033] The disassembly and assembly method for the hot gas duct in the maintenance of a high-temperature gas-cooled reactor nuclear power plant provided by the embodiments of the present application uses the limited space inside the steam generator compartment of the high-temperature gas-cooled reactor to disassemble and assemble the hot gas duct, the hot gas duct housing, and the steam generator, so as to realize the replacement of the sealing rings between the various hot gas duct segments of the hot gas duct, the inspection of the connecting bolts, and other maintenance work. During disassembly and assembly, first, disconnect the connection between the fourth hot gas duct segment and the third hot gas duct segment of the hot gas duct, and between the steam generator and the hot gas duct housing, and move the steam generator away from the reactor pressure vessel to provide space for the disassembly of the hot gas duct. Secondly, the fourth hot gas duct segment is translated with the steam generator, the third hot gas duct segment is disassembled within the operation space vacated after the steam generator is displaced, the hot gas duct housing and the second hot gas duct segment are lifted and lowered synchronously, and the first hot gas duct segment is disassembled and assembled within the space vacated by the overall downward movement of the hot gas duct housing and the second hot gas duct segment. According to the length characteristics of the various hot gas duct segments of the hot gas duct, the disassembly and assembly steps are reasonably arranged to realize the disassembly and assembly between the reactor pressure vessel, the hot gas duct, the hot gas duct housing, and the steam generator, facilitating the creation of conditions for the replacement of the sealing rings between the various hot gas duct segments of the hot gas duct, the inspection of the connecting bolts, and other maintenance work. Brief Description of the Drawings

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some examples or embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings, and the present application can also be applied to other similar scenarios according to the provided drawings. Unless obvious from the language context or otherwise stated, the same reference numerals in the figures represent the same structure or operation.

[0035] Figure 1 is a flowchart of the disassembly and assembly method for the hot gas duct in the maintenance of a high-temperature gas-cooled reactor nuclear power plant disclosed in the present application

[0036] Figure 2 is a schematic structural diagram of the primary equipment in the primary circuit of a high-temperature gas-cooled reactor nuclear power plant disclosed in the present application;

[0037] Figure 3 is a schematic structural diagram of the connection between the hot gas duct and the hot gas duct housing and the reactor pressure vessel and the steam generator disclosed in the present application;

[0038] Figure 4 is a schematic structural diagram of the separation of the steam generator from the hot gas duct and the hot gas duct housing disclosed in the present application;

[0039] Figure 5It is a schematic structural diagram after the separation of the third hot gas duct section and the second hot gas duct section disclosed in this application;

[0040] Figure 6 It is a schematic structural diagram after the translation of the hot gas duct housing in this application;

[0041] Figure 7 It is a schematic structural diagram after the disassembly of the second hot gas duct section of the hot gas duct disclosed in this application;

[0042] Figure 8 It is a schematic structural diagram after the separation of the second hot gas duct section and the first hot gas duct section of the hot gas duct disclosed in this application;

[0043] Figure 9 It is a schematic structural diagram after the separation of the first hot gas duct section of the hot gas duct disclosed in this application and the core shell;

[0044] Figure 10 It is a schematic structural diagram after the connection of the first hot gas duct section of the hot gas duct disclosed in this application and the core shell;

[0045] Figure 11 It is a schematic structural diagram after the connection of the second hot gas duct section and the first hot gas duct section disclosed in this application;

[0046] Figure 12 It is a schematic structural diagram after the connection of the hot gas duct housing and the reactor pressure vessel disclosed in this application;

[0047] Figure 13 It is a schematic structural diagram after the connection of the third hot gas duct section and the second hot gas duct section of the hot gas duct disclosed in this application.

[0048] Among them:

[0049] 01. Reactor pressure vessel, 02. Core shell, 03. Hot gas duct housing, 04. Hot gas duct, 05. Steam generator, 06. Main steam detachable pipe section, 07. First main bolt, 08. Second main bolt, 09. Cold helium gas lift pipe, 10. First hot gas duct section, 11. Second hot gas duct section, 12. Third hot gas duct section, 13. Fourth hot gas duct section, 14. Third sealing ring, 15. Second sealing ring, 16. Fifth sealing ring, 17. First sealing ring, 18. Fourth sealing ring, 19. Main feed water detachable pipe section, 20. Elbow. Detailed implementation manners

[0050] The present application will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related application, rather than limiting the application. The described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0051] It should be noted that for the convenience of description, only the parts related to the relevant application are shown in the drawings. Without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0052] It should be understood that the "system", "device", "unit" and / or "module" used in the present application are a method for distinguishing different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the word can be replaced by other expressions.

[0053] As shown in the present application and the claims, unless the context clearly indicates an exception, words such as "a", "an", "one" and / or "the" are not specifically singular, but may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of the clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements. An element defined by the statement "comprising one..." does not exclude the existence of another identical element in the process, method, article or device including the element.

[0054] Among them, in the description of the embodiments of the present application, unless otherwise specified, " / " means "or". For example, A / B may mean A or B; the "and / or" herein is only a description of the association relationship of the associated objects, indicating that three relationships may exist. For example, A and / or B may mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present application, "a plurality" means two or more than two.

[0055] Hereinafter, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0056] In this application, flowcharts are used to illustrate the operations performed by the system according to the embodiments of this application. It should be understood that the preceding or subsequent operations do not necessarily need to be executed precisely in sequence. On the contrary, the steps can be processed in reverse order or simultaneously. At the same time, other operations can also be added to these processes, or one or more steps can be removed from these processes.

[0057] Please refer to Figures 1-13 。

[0058] Some embodiments of this application disclose a method for disassembling and assembling a hot gas duct for maintenance of a high-temperature gas-cooled reactor nuclear power plant, including the following steps:

[0059] 1) Remove the cold helium gas riser 09 and elbow 20 inside the steam generator 05, and remove the main steam detachable pipe section 06 and the main feed water detachable pipe section 19 connected to the steam generator 05. As Figure 2 shown, separate the steam generator 05 from the cold helium gas riser 09 and elbow 20, and separate the steam generator 05 from the main steam detachable pipe section 06 and the main feed water detachable pipe section 19. This step is to remove the pipeline structure on the steam generator 05 that affects the movement of the steam generator 05. In step 1), the steam generator 05 still has a structure connected to the hot gas duct 04, and the steam generator 05 is not moved temporarily. At this time, a steam generator adjustment tooling for adjusting the position of the steam generator 05 can be connected to the steam generator 05. The steam generator adjustment tooling is used for the movement and installation adjustment of the steam generator 05;

[0060] 2) Disconnect the connection between the fourth hot gas duct section 13 and the third hot gas duct section 12 of the hot gas duct 04 and the connection between the steam generator 05 and the hot gas duct housing 03. At this time, the connection structure between the hot gas duct 04 and the hot gas duct housing 03 and the steam generator 05 is disconnected. As Figure 3 shown, move the steam generator 05 in the direction away from the reactor pressure vessel 01. Specifically, when it comes to the movement of the steam generator 05, it is preferred to move it through the steam generator adjustment tooling first. The movement of the steam generator 05 provides space for the disassembly and assembly of the hot gas duct 04. Since one side of the hot gas duct 04 connected to the steam generator 05 loses support, a temporary support structure, such as a cushion block, etc., needs to be set between the hot gas duct housing 03 and the second hot gas duct section 11 at the end of the hot gas duct 04 close to the steam generator 05;

[0061] 3) Disconnect the third hot gas duct section 12 of the hot gas duct 04 from the second hot gas duct section 11. Specifically, use a tooling or tool to remove the first connecting bolt used to connect the third hot gas duct section 12 and the second hot gas duct section 11, so that the third hot gas duct section 12 and the second hot gas duct section 11 are separated. At this time, the third hot gas duct section 12 is an independent structure and can move within the space vacated after the steam generator 05 moves. The third hot gas duct section 12 is separated from the hot gas duct 04, increasing the space for disassembly and assembly of the remaining structure of the hot gas duct 04 and reducing the difficulty of disassembling the remaining structure of the hot gas duct 04;

[0062] 4) Disconnect the hot gas duct housing 03 from the reactor pressure vessel 01. Specifically, use a special tool to remove the first main bolt 07 connecting the hot gas duct housing 03 and the reactor pressure vessel 01, and remove the temporary support structure between the hot gas duct housing 03 and the second hot gas duct section 11. At this time, the hot gas duct housing 03 can move between the reactor pressure vessel 01 and the moved steam generator 05 along the axis direction of the second hot gas duct section 11. As Figure 5 shown, when the hot gas duct housing 03 moves towards the steam generator 05, the second connecting bolt connecting the first branch pipe section and the second branch pipe section inside the second hot gas duct section 11, and the third connecting bolt connecting the second hot gas duct section 11 and the first hot gas duct section 10 will be exposed. It should be noted here that when removing the temporary support structure between the hot gas duct housing 03 and the second hot gas duct section 11, the second hot gas duct 11 can be lifted. The lifting position of the second hot gas duct 11 is close to the steam generator 05;

[0063] 5) Disconnect the second hot gas duct section 11 from the first hot gas duct section 10 of the hot gas duct 04. At this time, it is necessary to use a lifting tool to lift one end of the second hot gas duct section 11 close to the reactor pressure vessel 01. After disconnecting, temporary support structures need to be set between both ends of the second hot gas duct section 11 and the housing 03, and the lifting structures at both ends of the second hot gas duct section 11 need to be removed.

[0064] Specifically, to disconnect the connection structure between the second hot gas duct section 11 and the first hot gas duct section 10, use a tooling or tool to remove the third connecting bolt between the first hot gas duct section 10 and the second hot gas duct section 11. As Figure 7As shown, the separation of the reactor pressure vessel 01 from the hot gas duct housing 03 and the separation of the second hot gas duct section 11 from the first hot gas duct section 10 are achieved through steps 4) and 5). At this time, the second hot gas duct section 11 and the hot gas duct housing 03 form an independent structure, which is neither connected to the reactor pressure vessel 01 nor to the steam generator 05. The whole formed by the second hot gas duct section 11 and the hot gas duct housing 03 can move between the reactor pressure vessel 01 and the steam generator 05. It should be noted that the whole formed by the second hot gas duct section 11 and the hot gas duct housing 03 can move between the reactor pressure vessel 01 and the steam generator 05 can be a vertical movement or a movement along the axis direction of the second hot gas duct section 11;

[0065] Move the whole composed of the second hot gas duct section 11 and the hot gas duct housing 03 downward. The whole composed of the second hot gas duct section 11 and the hot gas duct housing 03 is arranged out of alignment relative to the first hot gas duct section 10. Specifically, move the whole composed of the second hot gas duct section 11 and the hot gas duct housing 03 toward the bottom of the steam generator compartment to provide space for the disassembly of the first hot gas duct section 10 and ensure that the first hot gas duct section 10 can be removed from the hot gas duct nozzle flange of the reactor pressure vessel 01, as Figure 8 shown.

[0066] Disconnect the connection between the first hot gas duct section 10 and the reactor core housing 02. Specifically, remove the fourth connection bolts used to connect the first hot gas duct section 10 and the reactor core housing 02 through a tooling or tool, as Figure 8 shown, and move the first hot gas duct section 10 out of the hot gas duct nozzle flange of the reactor pressure vessel 01;

[0067] 7) Connect the first hot gas duct section 10 and the reactor core housing 02, as Figure 9 shown. Specifically, connect the first hot gas duct section 10 and the reactor core housing 02 through new fourth connection bolts and spot weld them;

[0068] 8) Move the whole composed of the second hot gas duct section 11 and the hot gas duct housing 03 upward. Specifically, move the whole composed of the second hot gas duct section 11 and the housing 03 toward the top of the steam generator compartment.

[0069] Lift the second hot gas duct section 11 through a lifting structure and remove the temporary support structure between the two ends of the second hot gas duct section 11 and the hot gas duct housing 03. At this time, the second hot gas duct section 11 can move toward the reactor pressure vessel 01 inside the hot gas duct housing 03, as Figure 10As shown in the figure, connect the first hot gas duct section 10 and the second hot gas duct section 11. Specifically, remove the lifting structure on the side of the second hot gas duct section 11 close to the reactor pressure vessel 01, connect the first hot gas duct section 10 and the second hot gas duct section 11 through new third connecting bolts, and spot weld.

[0070] As Figure 11 shown in the figure, move the hot gas duct housing 03 towards the direction of the reactor pressure vessel 01, connect the hot gas duct housing 03 and the reactor pressure vessel 01, and connect the hot gas duct housing 03 and the reactor pressure vessel 01 through new or reusable first main bolts 07 after disassembly.

[0071] 9) Install a temporary support structure between the side of the second hot gas duct section 11 close to the steam generator 05 and the hot gas duct housing 03, remove the lifting structure on the side of the second hot gas duct section 11 close to the steam generator 05, connect the second hot gas duct section 11 and the third hot gas duct section 12. As Figure 12 shown in the figure, specifically, connect the second hot gas duct section 11 and the third hot gas duct section 12 through new first connecting bolts, and spot weld, and remove the temporary support structure between the side of the second hot gas duct section 11 close to the steam generator 05 and the hot gas duct housing 03.

[0072] 10) Move the steam generator 05 towards the direction close to the reactor pressure vessel 01, connect the steam generator 05 and the hot gas duct housing 03, and connect the fourth hot gas duct section 13 and the third hot gas duct section 12. The fourth hot gas duct section 13 and the third hot gas duct section 12 are connected through fifth connecting bolts.

[0073] 11) Connect the steam generator 05 with the cold helium riser 09 and the elbow 20, and connect the steam generator 05 with the main steam removable pipe section 06 and the main feed water removable pipe section 19.

[0074] Among them, in step 3) or step 9), replace the first sealing ring 17 between the third hot gas duct section 12 and the second hot gas duct section 11, and / or, repair the first connecting bolts between the third hot gas duct section 12 and the second hot gas duct section 11.

[0075] In step 5) or step 8), replace the second sealing ring 15 between the second hot gas duct section 11 and the first hot gas duct section 10, and / or, repair the third connecting bolts between the second hot gas duct section 11 and the first hot gas duct section 10.

[0076] In step 6), replace the third sealing ring 14 between the first hot gas duct section 10 and the core shell 02, and / or, repair the fourth connecting bolts between the third hot gas duct 10 and the core shell 2.

[0077] Replace the fourth sealing ring 18 between the fourth hot gas duct section 13 and the third hot gas duct section 12 in step 2) or step 10), and / or repair the fifth connecting bolt between the fourth hot gas duct section 13 and the third hot gas duct section 12.

[0078] Through steps 1)-6), the gradual disassembly of the hot gas duct 04, the steam generator 05, and the hot gas duct housing 03 is achieved, enabling the replacement of the sealing rings on the hot gas duct 04, the inspection and repair of the connecting bolts, and other maintenance work.

[0079] Through steps 7)-11), the connection of the hot gas duct 04, the steam generator 05, and the hot gas duct housing 03 is restored. The assembly directions disclosed in steps 7)-11) are opposite to the disassembly directions disclosed in steps 1)-6), enabling the replacement of the sealing rings, the inspection and repair of the connecting bolts, and other maintenance work.

[0080] Here, the disconnection is described. Taking the disconnection of the third hot gas duct section 12 and the second hot gas duct section 11 as an example, the disconnection is to remove the connection structure used to connect the third hot gas duct section 12 and the second hot gas duct section 11, which refers to the first connecting bolt here.

[0081] The disassembly and assembly method for maintaining the hot gas duct of a high-temperature gas-cooled reactor nuclear power plant disclosed in this application requires the disassembly of equipment including the hot gas duct 04, the hot gas duct housing 03, and the steam generator 05. Among them, the disassembled structures on the steam generator 05 include the cold helium lift pipe 09, the elbow 20, the main steam detachable pipe section 06, and the main feed water detachable pipe section 19. The disassembled structures on the hot gas duct 04 include the third hot gas duct section 12, the second hot gas duct section 11, the first hot gas duct section 10, the fourth hot gas duct section 13, the first sealing ring 17, the second sealing ring 15, the third sealing ring 14, the fourth sealing ring 18, the fifth sealing ring 16, the first main bolt 07, the second main bolt 08, the first connecting bolt, the second connecting bolt, the third connecting bolt, the fourth connecting bolt, and the fifth connecting bolt, etc.

[0082] As Figure 3 shown, the hot gas duct sections on the hot gas duct 04 are, from left to right, the first hot gas duct section 10, the second hot gas duct section 11, the third hot gas duct section 12, and the fourth hot gas duct section 13. The second hot gas duct section 11 includes, from left to right, the first branch pipe section and the second branch pipe section.

[0083] The disassembly and assembly method for maintaining the hot gas duct of a high-temperature gas-cooled reactor nuclear power plant disclosed in this application is used to guide the disassembly and assembly work of maintaining the hot gas duct of a high-temperature gas-cooled reactor nuclear power plant, facilitating the creation of conditions for replacing the sealing rings of the hot gas duct 04, inspecting and repairing the connecting bolts of each section of the hot gas duct 04, and other maintenance work.

[0084] The disassembly and assembly method for the hot gas duct in the maintenance of a high-temperature gas-cooled reactor nuclear power plant disclosed in this application utilizes the limited space inside the steam generator compartment of the high-temperature gas-cooled reactor to disassemble and assemble the hot gas duct 04, realizing the replacement of the sealing ring of the hot gas duct 04, the inspection of the connecting bolts of each section, and other maintenance work. During disassembly and assembly, first, disconnect the connection between the fourth hot gas duct section 13 and the third hot gas duct section 12, and the connection between the steam generator 05 and the hot gas duct housing 03. Move the steam generator 05 in the direction away from the reactor pressure vessel 01 to provide space for the disassembly of the hot gas duct 04 and the hot gas duct housing 03. Then, the fourth hot gas duct section 13 is translated with the steam generator 05, the third hot gas duct section 12 is disassembled and assembled within the operating space vacated after the steam generator 05 is displaced, the hot gas duct housing 03 and the second hot gas duct section 11 are lifted and lowered synchronously, and the first hot gas duct section 10 is disassembled and assembled within the space vacated by the overall downward movement of the housing 03 and the second hot gas duct section 11. According to the length characteristics of each structure of the hot gas duct 04, this application reasonably arranges the disassembly and assembly steps to realize the disassembly and assembly between the reactor pressure vessel, the hot gas duct, the hot gas duct housing, and the steam generator, facilitating the replacement of the sealing ring of each hot gas duct section of the hot gas duct, the inspection of the connecting bolts, and other maintenance work.

[0085] In this application, the fourth hot gas duct section 13 cannot be disassembled from the steam generator 05, and only the third hot gas duct section 12 can be separated from the fourth hot gas duct section 13.

[0086] In some embodiments of this application, before disconnecting the connection between the second hot gas duct section 11 and the first hot gas duct section 10 in step 5), the following steps are further included: moving the hot gas duct housing 03 in the direction of the steam generator 05, disconnecting the connection between the first branch duct section and the second branch duct section inside the second hot gas duct section 11, replacing the fifth sealing ring 16 between the first branch duct section and the second branch duct section, and / or inspecting the second connecting bolt between the first branch duct section and the second branch duct section;

[0087] Connect the first branch duct section and the second branch duct section to reconstitute the second hot gas duct section 11;

[0088] Fix the second hot gas duct section 11 inside the hot gas duct housing 03.

[0089] Move the hot gas duct housing 03 in the direction away from the reactor pressure vessel 01, as Figure 5 shown, to expose the second connecting bolt for connecting the first branch pipe section and the second branch pipe section inside the second hot gas duct section 11, and disconnect the connection between the first branch duct section and the second branch duct section. Specifically, remove the second connecting bolt through a tooling or tool. At this time, the fifth sealing ring 16 can be disassembled, as Figure 6As shown, move the second branch duct section away from the reactor pressure vessel 01 to replace the fifth sealing ring 16, thereby achieving the replacement of the fifth sealing ring 16.

[0090] The connection between the first branch duct section and the second branch duct section is made through new second connection bolts and then spot-welded. After replacing the fifth sealing ring 16, the first branch duct section and the second branch duct section are reassembled.

[0091] In some other embodiments of the present application, after moving downward the whole formed by the second hot gas duct section 11 and the hot gas duct housing 03 in step 5), or before moving upward the whole formed by the second hot gas duct section 11 and the hot gas duct housing 03 in step 8), the following steps are further included:

[0092] Move the hot gas duct housing 03 towards the steam generator 05 or the reactor pressure vessel 01;

[0093] Disconnect the connection between the first branch duct section and the second branch duct section inside the second hot gas duct section 11 and replace the fifth sealing ring 16;

[0094] Connect the first branch duct section and the second branch duct section to reconstitute the second hot gas duct section 11;

[0095] Fix the second hot gas duct section 11 inside the hot gas duct housing.

[0096] Move the hot gas duct housing 03 towards the steam generator 05 or the reactor pressure vessel 01 to expose the connection position between the first branch duct section and the second branch duct section inside the second hot gas duct section 11, and disconnect the connection between the first branch duct section and the second branch duct section inside the second hot gas duct section 11. Specifically, by removing the second connection bolts used to connect the first branch duct section and the second branch duct section inside the second hot gas duct section 11, replace the fifth sealing ring 16;

[0097] Connect the first branch duct section and the second branch duct section through new second connection bolts. After replacing the fifth sealing ring 16, the first branch duct section and the second branch duct section are reassembled.

[0098] For the method steps of disassembling, assembling and overhauling the second hot gas duct section 11 disclosed in the above two embodiments, specifically which method to choose is selected by those skilled in the art according to actual needs and will not be specifically limited herein.

[0099] Step 3) further includes placing the third hot gas duct section 12 in the hot gas duct nozzle flange of the steam generator 05 or temporarily connecting the third hot gas duct section 12 to the fourth hot gas duct section 13.

[0100] Instead of removing the third hot gas duct section 12 from the device, the third hot gas duct section 13 can be directly placed inside the hot gas duct nozzle flange of the steam generator 05 or temporarily connected to the fourth hot gas duct section 13, which can prevent damage to the third hot gas duct section 12.

[0101] Temporary connection means a temporary connection. The strength of the temporary connection is weaker than the connection strength between the third hot gas duct section 12 and the hot gas duct nozzle flange or the fourth hot gas duct section 13, and the temporary connection is made using parts that are convenient for installation and disassembly.

[0102] The above description is only a preferred embodiment of the present application and an explanation of the applied technical principles, and is not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. The scope of the application involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above application concept. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A method for disassembling and assembling a hot gas duct for maintenance of a high-temperature gas-cooled reactor nuclear power plant, characterized in that, Including the steps: 1) Remove the cold helium lift pipe (09) and elbow (20) inside the steam generator (05), and remove the main steam detachable pipe section (06) and main feed water detachable pipe section (19) connected to the steam generator (05); 2) Disconnect the fourth hot gas duct section (13) from the third hot gas duct section (12), and disconnect the steam generator (05) from the hot gas duct housing (03), and move the steam generator (05) away from the reactor pressure vessel (01); 3) Disconnect the third hot gas duct section (12) from the second hot gas duct section (11); 4) Disconnect the hot gas duct housing (03) from the reactor pressure vessel (01), and move the hot gas duct housing (03) towards the steam generator (05); 5) Disconnect the second hot gas duct section (11) from the first hot gas duct section (10), move the whole formed by the second hot gas duct section (11) and the hot gas duct housing (03) downward, and the whole formed by the second hot gas duct section (11) and the hot gas duct housing (03) is arranged out of alignment relative to the first hot gas duct section (10); 6) Disconnect the first hot gas duct section (10) from the core shell (02), and move the first hot gas duct section (10) out of the hot gas duct nozzle flange of the reactor pressure vessel (01); 7) Connect the first hot gas duct section (10) and the core shell (02); 8) Move the whole formed by the second hot gas duct section (11) and the hot gas duct housing (03) upward, connect the first hot gas duct section (10) and the second hot gas duct section (11), and at the same time connect the hot gas duct housing (03) and the reactor pressure vessel (01); 9) Connect the second hot gas duct section (11) and the third hot gas duct section (12); 10) Move the steam generator (05) towards the reactor pressure vessel (01), connect the steam generator (05) and the hot gas duct housing (03), and connect the fourth hot gas duct section (13) and the third hot gas duct section (12); 11) Connect the steam generator (05) with the cold helium lift pipe (09) and the elbow (20), and connect the steam generator (05) with the main steam detachable pipe section (06) and the main feed water detachable pipe section (19); Wherein, in step 3) or step 9), replace the first sealing ring (17) between the third hot gas duct section (12) and the second hot gas duct section (11), and / or repair the first connecting bolt between the third hot gas duct section (12) and the second hot gas duct section (11); In step 5) or step 8), replace the second sealing ring (15) between the second hot gas duct section (11) and the first hot gas duct section (10), and / or repair the third connecting bolt between the second hot gas duct section (11) and the first hot gas duct section (10); In step 6), replace the third sealing ring (14) between the first hot gas duct section (10) and the core shell (02), and / or, repair the fourth connecting bolt between the third hot gas duct section (12) and the core shell (02); In step 2) or step 10), replace the fourth sealing ring (18) between the fourth hot gas duct section (13) and the third hot gas duct section (12), and / or, repair the fifth connecting bolt between the fourth hot gas duct section (13) and the third hot gas duct section (12).

2. The disassembly and assembly method for the maintenance of the hot gas duct in a high-temperature gas-cooled reactor nuclear power plant according to claim 1, characterized in that, Before disconnecting the second hot gas duct section (11) from the first hot gas duct section (10) in step 5), the following steps are further included: Move the hot gas duct housing (03) towards the steam generator (05), disconnect the first branch duct section and the second branch duct section inside the second hot gas duct section (11), replace the fifth sealing ring (16) between the first branch duct section and the second branch duct section, and / or, overhaul the second connecting bolt between the first branch duct section and the second branch duct section; Connect the first branch duct section and the second branch duct section to reconstitute the second hot gas duct section (11); Fix the second hot gas duct section (11) within the hot gas duct housing (03).

3. The disassembly and assembly method for the maintenance of the hot gas duct of a high-temperature gas-cooled reactor nuclear power plant according to claim 1, wherein Before moving the whole formed by the second hot gas duct section (11) and the hot gas duct housing (03) downward in step 5), or before moving the whole formed by the second hot gas duct section (11) and the hot gas duct housing (03) upward in step 8), the following steps are further included: Move the hot gas duct housing (03) towards the steam generator (05) or the reactor pressure vessel (01); Disconnect the first branch duct section and the second branch duct section inside the second hot gas duct section (11), and replace the fifth sealing ring (16); Connect the first branch duct section and the second branch duct section to reconstitute the second hot gas duct section (11); Fix the second hot gas duct section (11) within the hot gas duct housing (03).

4. The disassembly and assembly method for the hot gas duct in the maintenance of a high-temperature gas-cooled reactor nuclear power plant according to claim 1, characterized in that, Step 3) further includes: Place the third hot gas duct section (12) within the hot gas duct nozzle flange of the steam generator (05) or temporarily connect the third hot gas duct section (12) to the fourth hot gas duct section (13).

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