A reactor coolant loop and method of installing the same

Abstract

This invention discloses a reactor coolant loop and its installation method. The reactor coolant loop includes a pressure vessel, a steam generator, a main pump, a hot section main pipeline, and a cold section main pipeline. The inlet and outlet nozzle faces of the steam generator are parallel to each other, while the inlet and outlet nozzle faces of the pressure vessel are perpendicular or parallel to each other, with the outlet nozzle face parallel to the inlet nozzle face of the steam generator. During the welding installation of the main pipelines of the reactor coolant loop, the four welds at both ends of the hot section and the cold section main pipelines are all horizontally fixed butt joints. This invention simplifies the reactor coolant loop structure and further reduces structural constraint, which can further reduce welding stress, simplify construction, reduce costs, shorten the construction period, and improve the safety and economy of nuclear power plant construction and operation.

Description

Technical Field

[0001] This invention relates to the field of nuclear industry coolant piping technology, and more specifically, to a reactor coolant loop and its installation method. Background Technology

[0002] Currently, the reactor coolant loop design of pressurized water reactor nuclear power plants in China mainly includes, as follows: Figure 1 As shown, this is a "hot section-transition section-cold section" configuration for the M310 reactor type, consisting of a reactor pressure vessel, steam generator, main pump, one hot section main pipe, one transition section main pipe, and one cold section main pipe. Its disadvantage is the relatively large number of installation welds on the main pipes. In one loop, there are two installation welds each in the hot and cold sections, and four in the transition section, for a total of eight welds. For a megawatt-class unit, there are a total of 24 welds across three loops, along with three welding positions: 2G (vertical fixed butt joint), 5G (horizontal fixed butt joint), and 6G (45-degree inclined fixed butt joint). This results in a large workload for main pipe welding preparation, welding procedure qualification, welding, non-destructive testing, and witnessing work, leading to a long installation and welding period.

[0003] Patent CN111599496B proposes a reactor coolant loop that can reduce the number of welds and improve the safety and economy of nuclear power plants. It can reduce the number of welds in the three loops of a 1,000 kW unit from 24 to 12. If a 1,000 kW unit adopts a two-loop scheme with an increased-capacity steam generator, the total number of welds can be further reduced to 8. However, its disadvantages include stringent requirements for the manufacturing and installation precision of the main equipment, making construction more difficult; secondly, the closed-loop installation welds of the reactor coolant loop have high constraint and high welding stress, which may require temporary support for a dedicated steam generator, leading to complex construction and increased costs.

[0004] Patent CN113871036B further proposes a reactor coolant loop that can reduce weld restraint, decrease welding stress, and improve the safety and economy of nuclear power plant construction and operation. However, it has several drawbacks: First, the closed-loop installation weld of the reactor coolant loop is located at the reactor coolant outlet and inlet nozzles of the reactor pressure vessel. During the welding of the closed-loop weld, the contraction requires the movement of the steam generator and main pipeline, increasing the construction difficulty. Second, when setting up the adjustment section in the cold section-transition section, additional on-site measurement and processing space and transportation are required. Third, the loop installation welding needs to be carried out in multiple steps sequentially, resulting in low construction efficiency, extended construction period, and increased costs.

[0005] In view of the above technical problems, this invention is hereby introduced. Summary of the Invention

[0006] The main objective of this invention is to provide a reactor coolant loop and its installation method, which can further reduce the constraint of the closed-loop installation weld of the reactor coolant loop, reduce the welding stress of the closed-loop installation, simplify the installation process, and improve the safety and economy of nuclear power plant construction and operation.

[0007] To achieve the above objectives, according to one aspect of the present invention, a reactor coolant loop is provided, comprising a reactor pressure vessel and a steam generator. The reactor pressure vessel includes a pressure vessel outlet nozzle and a pressure vessel inlet nozzle, and the steam generator includes a steam generator inlet nozzle and a steam generator outlet nozzle. The reactor coolant loop further includes a main pipeline, which includes a hot section main pipeline connecting the pressure vessel outlet nozzle and the steam generator inlet nozzle, and a cold section main pipeline connecting the steam generator outlet nozzle and the pressure vessel inlet nozzle.

[0008] The inlet nozzle face and outlet nozzle face of the steam generator are parallel to each other, while the inlet nozzle face and outlet nozzle face of the pressure vessel are perpendicular or parallel to each other, and the outlet nozzle face of the pressure vessel is parallel to the inlet nozzle face of the steam generator. When the main pipeline of the reactor coolant loop is installed and welded, the welding positions of the four welds at both ends of the hot section main pipeline and both ends of the cold section main pipeline are all horizontal fixed butt joints.

[0009] Furthermore, the reactor coolant loop also includes a main pump, and the hot section main pipe and / or cold section main pipe are prefabricated as an integral structure with the pump casing of the main pump.

[0010] Alternatively, the main pump can be located at the bottom of the steam generator to obtain a steam generator with an attached main pump.

[0011] Furthermore, the main pump steam generator includes an inlet main pump and an outlet main pump. The inlet main pump includes an inlet main pump casing and an inlet main pump motor. The outlet main pump includes an outlet main pump casing and an outlet main pump motor. The axial direction of the impeller in the inlet main pump casing and the inlet main pump motor is parallel or perpendicular to the horizontal plane. The axial direction of the impeller in the outlet main pump casing and the outlet main pump motor is perpendicular to the horizontal plane.

[0012] Furthermore, an adjustment section is provided at the end of the main pipeline.

[0013] Furthermore, during the installation of the reactor coolant loop, the equipment used includes a steam generator nozzle shadow body, which includes two shadow nozzles corresponding to the steam generator inlet nozzle and the steam generator outlet nozzle, respectively. The end face dimensions and position dimensions of the two shadow nozzles are consistent with the dimensions of the corresponding nozzles of the steam generator.

[0014] Furthermore, the steam generator nozzle shadow body also includes a shadow body bottom end cap and a shadow platform. The shadow body bottom end cap corresponds to the bottom end cap of the steam generator, and the shadow platform has the same dimensions as the platform supporting the steam generator. The steam generator nozzle shadow body is installed on the steam generator support through the shadow platform of the shadow body bottom end cap. Two shadow nozzles are set on one side of the shadow body bottom end cap, and a counterweight is provided on the other side of the shadow body bottom end cap.

[0015] To achieve the above objectives, according to another aspect of the present invention, a method for installing a reactor coolant loop is provided, the method comprising the following steps:

[0016] The steps for fabricating and installing the nozzle shadow body are as follows: fabricate the steam generator nozzle shadow body according to the steam generator, and install the steam generator nozzle shadow body on the steam generator support;

[0017] The measurement and processing steps are based on the measurement data of the shadow nozzle of the steam generator nozzle body and the nozzle of the reactor pressure vessel that has been installed in place, and the adjustment section at the end of the main pipeline is measured and processed.

[0018] The post-processing and placement step involves measuring and placing the processed main pipe into the installation position.

[0019] The procedure for removing the nozzle shadow body is to remove the steam generator nozzle shadow body from the steam generator support.

[0020] Steam generator installation steps: Place the steam generator into the installation position and position it on the steam generator support;

[0021] Installation steps for assembling and installing nozzles and main pipelines: Steam generator nozzles, pressure vessel nozzles and main pipelines are assembled and installed.

[0022] The welding process involves welding the nozzle to the main pipe.

[0023] Furthermore, when the inlet nozzle end face and the outlet nozzle end face of the pressure vessel are perpendicular to each other, the installation method includes the following steps:

[0024] Before the measurement and processing steps, the reactor pressure vessel and the hot section main pipeline are brought into the installation position and welded between the end face of the pressure vessel outlet nozzle and the end face of the pressure vessel side of the hot section main pipeline.

[0025] In the measurement and processing steps, after assembling and installing the steam generator side end face of the hot section main pipeline with the inlet shadow nozzle of the steam generator nozzle shadow body, the adjustment section of the cold section main pipeline end is measured and processed based on the measurement data of the outlet shadow nozzle of the steam generator nozzle shadow body and the inlet nozzle of the pressure vessel, and after correction according to the welding shrinkage of the weld between the pressure vessel inlet nozzle and the cold section main pipeline.

[0026] After the processing and positioning steps, the two ends of the cold section main pipe are respectively paired and installed with the outlet nozzle of the steam generator nozzle body and the inlet nozzle of the pressure vessel. The end face of the outlet nozzle of the steam generator nozzle body is offset from the end face of the cold section main pipe by a certain amount to account for the welding shrinkage of the weld between the pressure vessel inlet nozzle and the cold section main pipe.

[0027] Furthermore, the installation method also includes the following steps:

[0028] During the main pipeline assembly and installation process, the end face of the steam generator outlet nozzle is offset from the end face of the cold section main pipeline by a certain amount to account for the welding shrinkage of the weld between the pressure vessel inlet nozzle and the cold section main pipeline.

[0029] In the welding process, the weld between the pressure vessel inlet nozzle and the cold section main pipeline is welded first. After the weld shrinks, the end face of the steam generator outlet nozzle is aligned with the end face of the cold section main pipeline. Then, the welds between the steam generator inlet nozzle and the hot section main pipeline, and between the steam generator outlet nozzle and the cold section main pipeline are welded simultaneously.

[0030] Furthermore, prior to the steam generator installation step, there are also construction steps for the main piping room and the steam generator room, which can be modularly designed.

[0031] Furthermore, when the inlet nozzle end face and the outlet nozzle end face of the pressure vessel are parallel to each other, the installation method includes the following steps:

[0032] In the measurement and processing steps, the measurement data of the shadow nozzle of the steam generator nozzle body and the inlet and outlet nozzles of the installed reactor pressure vessel are used as the benchmark to measure and process the adjustment sections at the ends of the hot section main pipeline and the cold section main pipeline respectively.

[0033] In the main pipeline assembly and installation process, first assemble and install the cold section main pipeline and the hot section main pipeline with the inlet and outlet nozzles of the reactor pressure vessel, and then assemble and install the cold section main pipeline and the hot section main pipeline with the inlet and outlet nozzles of the steam generator.

[0034] During the welding process, the pipe ends on both sides of the hot section main pipe and the cold section main pipe are simultaneously and evenly welded to the four weld seams between the two nozzles of the reactor pressure vessel and the inlet and outlet nozzles of the steam generator.

[0035] By applying the above-described technical solution of the present invention, at least the following beneficial effects are achieved:

[0036] 1. This invention employs a steam generator with parallel inlet and outlet nozzle ends, a reactor pressure vessel with perpendicular inlet and outlet nozzle ends, and a dedicated main pump setup. Furthermore, during the installation and welding of the main pipeline in the entire loop, the welding positions of the four welds at both ends of the hot section main pipeline connecting the reactor pressure vessel and the steam generator, as well as at both ends of the cold section main pipeline, are all horizontally fixed butt joints. This simplifies the reactor coolant loop structure and allows the closed-loop installation welds to be located at the coolant outlet nozzle and coolant inlet nozzle of the steam generator. During closed-loop installation welding shrinkage, only the steam generator needs to be moved, not the main pipeline, further reducing structural constraint and welding stress.

[0037] 2. The reactor coolant loop installation method of the present invention, by designing and installing the steam generator nozzle shadow body, is equivalent to installing the actual steam generator in the designated position. This allows for the pre-measurement of the relevant dimensional data of the adjustment sections at both ends of the main pipeline, ensuring that the steam generator can be precisely aligned with the main pipeline, thus avoiding additional on-site measurement and processing space and transportation.

[0038] 3. When the reactor coolant loop of the present invention adopts a reactor pressure vessel with parallel inlet and outlet nozzle end faces, the installation welds of each loop can be optimized from multiple sequential welding steps to one simultaneous welding step, thereby greatly improving construction efficiency.

[0039] 4. The embodiments of the present invention simplify the reactor coolant loop structure and the installation and construction process and complexity, which helps to reduce costs, shorten the construction period, and improve the safety and economy of nuclear power plant construction and operation. Attached Figure Description

[0040] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0041] Figure 1 A schematic diagram of a reactor coolant loop in the prior art is shown;

[0042] Figure 2 A bottom view schematic diagram of the reactor coolant loop of Example 1 is shown;

[0043] Figure 3 A side view of the reactor coolant loop in Example 1 is shown.

[0044] Figure 4 A schematic diagram of the steam generator of Embodiment 1 is shown;

[0045] Figure 5 A schematic diagram of the pressure vessel of Embodiment 1 is shown;

[0046] Figure 6 A schematic diagram of Embodiment 1 showing the main pump casing and the cold section main pipeline prefabricated as one unit;

[0047] Figure 7 The image shows a front view of the steam generator nozzle after installation.

[0048] Figure 8 A side view of the steam generator nozzle after installation is shown;

[0049] Figure 9 A bottom view schematic diagram of the reactor coolant loop in Example 2 is shown;

[0050] Figure 10 A side view of the reactor coolant loop is shown in Example 2 or Example 4.

[0051] Figure 11 A schematic diagram of the steam generator with main pump in Embodiment 2 is shown;

[0052] Figure 12 A bottom view schematic diagram of one of the reactor coolant loops in Example 4 is shown;

[0053] Figure 13 A schematic diagram of the pressure vessel of Embodiment 4 is shown;

[0054] Figure 14 A bottom view schematic diagram of another reactor coolant loop in Example 4 is shown;

[0055] Figure 15 A side view of another reactor coolant loop in Example 4 is shown.

[0056] The above figures include the following reference numerals:

[0057] 1. Reactor pressure vessel; 2. Pressure vessel inlet nozzle end face; 3. Pressure vessel inlet nozzle; 4. Pressure vessel outlet nozzle end face; 5. Pressure vessel outlet nozzle; 6. Main pump pressure vessel side cold section main pipeline end face; 7. Main pump pressure vessel side main pipeline; 8. Main pump; 9. Main pump steam generator side cold section main pipeline end face; 10. Main pump steam generator side main pipeline; 11. Steam generator outlet nozzle end face; 12. Steam generator outlet nozzle; 13. Steam generator; 14. Steam generator inlet nozzle; 15. Steam generator inlet nozzle end face; 16. Hot section main pipeline steam generator side end face; 17. Hot section main pipeline; 8. Pressure vessel side end face of the hot section main pipeline; 19. Pressure vessel side end face of the cold section main pipeline; 20. Cold section main pipeline; 21. Steam generator side end face of the cold section main pipeline; 22. Outlet nozzle end face of the main pump steam generator; 23. Outlet nozzle of the main pump steam generator; 24. Outlet main pump casing; 25. Outlet main pump motor; 26. Main pump steam generator; 27. Inlet main pump motor; 28. Inlet main pump casing; 29. ​​Inlet nozzle of the main pump steam generator; 30. Inlet nozzle end face of the main pump steam generator; 31. Shadow nozzle; 32. Shadow body bottom end cap; 33. Counterweight; 34. Shadow platform; 35. Steam generator support. Detailed Implementation

[0058] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0059] The present invention will be further described in detail below with reference to specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed by the present invention. The term "comprising" indicates the presence of a feature, but does not exclude the presence or addition of one or more other features. The terms "lateral," "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the purpose of description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0060] In this description, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0061] Example 1:

[0062] like Figure 2 and Figure 3 As shown, a specific embodiment 1 of the present invention provides a reactor coolant loop, including a reactor pressure vessel 1 and a steam generator 13. Wherein, as... Figure 4 As shown, the bottom end cap of the steam generator 13 is provided with a steam generator inlet nozzle 14 and a steam generator outlet nozzle 12. The end face 15 of the steam generator inlet nozzle is parallel to the end face 11 of the steam generator outlet nozzle. Figure 5 As shown, the reactor pressure vessel 1 is provided with a pressure vessel inlet nozzle 3 and a pressure vessel outlet nozzle 5, and the end face 2 of the pressure vessel inlet nozzle and the end face 4 of the pressure vessel outlet nozzle are perpendicular to each other.

[0063] The reactor coolant loop also includes a hot section main pipe 17 connecting the pressure vessel outlet nozzle 5 and the steam generator inlet nozzle 14, and a cold section main pipe connecting the steam generator outlet nozzle 12 and the pressure vessel inlet nozzle 3.

[0064] like Figure 6 As shown, the reactor coolant loop also includes the main pump 8. The main pump pressure vessel side main pipe 7, the main pump steam generator side main pipe 10, and the pump casing of the main pump 8 are prefabricated as an integrated structure, which is the cold section main pipe. The end face 6 of the main pump pressure vessel side cold section main pipe and the end face 9 of the main pump steam generator side cold section main pipe are perpendicular to each other.

[0065] Figure 2In this configuration, the steam generator side end face 16 and the pressure vessel side end face 18 of the hot section main pipeline are the two end faces of the hot section main pipeline 17. The hot section main pipeline 17 is connected between the steam generator inlet nozzle end face 14 and the pressure vessel outlet nozzle end face 5 by welding the steam generator inlet nozzle end face 15 to the steam generator side end face 16 and the pressure vessel outlet nozzle end face 4 to the pressure vessel side end face 18. The integrated cold section main pipeline is connected between the pressure vessel inlet nozzle end face 3 and the steam generator outlet nozzle end face 12 by welding the pressure vessel inlet nozzle end face 2 to the main pump pressure vessel side cold section main pipeline end face 6 and the main pump steam generator side cold section main pipeline end face 9 to the steam generator outlet nozzle end face 11, with the pressure vessel outlet nozzle end face 4 parallel to the steam generator inlet nozzle end face 15.

[0066] As described above, the reactor coolant loop, such as Figure 3 As shown, during the installation and welding of the main pipeline in the entire loop, the welding positions of the four welds at both ends of the hot section main pipeline 17 and both ends of the cold section main pipeline are all horizontal fixed butt joints.

[0067] Furthermore, the reactor coolant loop as described above, such as Figure 2 As shown, adjustment sections are provided at the pipe end of the main pipeline 10 on the steam generator side of the main pump and at the pipe end of the main pipeline 7 on the pressure vessel side of the main pump.

[0068] like Figure 7 and Figure 8 As shown, during the installation of the reactor coolant loop, a steam generator nozzle shadow body is manufactured. The steam generator nozzle shadow body includes an inlet shadow nozzle and an outlet shadow nozzle corresponding to the steam generator inlet nozzle 14 and the steam generator outlet nozzle 12, respectively. The end face dimensions and position dimensions of the two shadow nozzles 31 are consistent with the dimensions of the corresponding nozzles of the steam generator 13.

[0069] Furthermore, the steam generator nozzle shadow body also includes a shadow body bottom end cap 32 and a shadow body platform 34. The shadow body bottom end cap 32 corresponds to the bottom end cap of the steam generator 13, and the shadow body platform 34 has the same position and size as the platform supporting the steam generator 13. The shadow body bottom end cap 32 is mounted on the steam generator support 35 through the shadow body platform 34. Two shadow nozzles 31 are set on one side of the shadow body bottom end cap 32, and a counterweight 33 is provided on the other side of the shadow body bottom end cap 32. In specific implementation, the steam generator nozzle shadow body can be made and used by mechanical or electromechanical physical means, or it can be used by making an electronic virtual body using three-dimensional scanning technology.

[0070] Preferably, the reactor coolant loop described above, including the steam generator 13 room, the main pump 8, the main pump pressure vessel side main pipe 7, the main pump steam generator side main pipe 10 room, and the hot section main pipe 17 room, adopt a modular design.

[0071] like Figure 2 and Figure 3 As shown above, the installation method of a reactor coolant loop includes the following steps:

[0072] (1) The reactor pressure vessel 1 and the hot section main pipeline 17 are respectively introduced into the installation position and placed in place.

[0073] (2) Install the weld between the outlet nozzle end face 4 of the pressure vessel and the side end face 18 of the hot section main pipeline pressure vessel.

[0074] (3) Steps for fabricating and installing the nozzle shadow body, such as Figure 7 and Figure 8 As shown, the dimensions and positions of the shadow platform 34 of the steam generator nozzle shadow body and the end faces and positions of the two shadow nozzles 31 are made, adjusted and copied to be the same as the dimensions of the actual steam generator 13 support platform and nozzle end faces 11, 15. Then, the steam generator nozzle shadow body is installed on the steam generator support 35. This step is equivalent to installing the actual steam generator 13 on the steam generator support 35.

[0075] (4) The steam generator side end face 16 of the hot section main pipeline is assembled and installed with the inlet end face of the steam generator nozzle shadow body; the data between the outlet end face of the steam generator nozzle shadow body and the inlet end face 2 of the pressure vessel is measured, and after correction according to the welding shrinkage of the weld between the pressure vessel inlet nozzle 3 and the cold section main pipeline, the measurement and processing dimensions of the main pump steam generator side main pipeline 10 and the main pump pressure vessel side main pipeline 7 with the pump casing of the main pump 8 installed in step (7) are obtained.

[0076] (5) Based on the measurement and processing dimensions of the main pump steam generator side main pipe 10 and the main pump pressure vessel side main pipe 7 with the main pump casing obtained in step (4), the adjustment sections at both ends of the cold section main pipe of the integrated structure are measured and processed to obtain the cold section main pipe suitable for installation in step (7).

[0077] (6) After processing, the cold section main pipe is placed in the appropriate position after processing. (7) After processing, the cold section main pipe is placed in the appropriate position.

[0078] (7) Assemble the steam generator nozzle shadow body outlet shadow nozzle end face, the main pump steam generator side main pipe 10 with the main pump 8 pump casing and the main pump pressure vessel side main pipe 7, and the pressure vessel inlet nozzle end face 2; wherein, the steam generator nozzle shadow body outlet shadow nozzle end face and the main pump steam generator side cold section main pipe end face 9 are offset by a section of the weld between the pressure vessel inlet nozzle end face 2 and the main pump pressure vessel side cold section main pipe end face 6.

[0079] (8) Installation of the steam generator room and main pipeline room modules.

[0080] (9) Nozzle shadow body removal procedure: Remove the steam generator nozzle shadow body.

[0081] (10) Steam generator installation steps: The steam generator 13 is introduced into the installation position and placed on the steam generator support 35.

[0082] (11) Installation steps for main pipe assembly: The steam generator inlet nozzle end face 15 is assembled and installed with the hot section main pipe steam generator side end face 16. At the same time, the steam generator outlet nozzle end face 11 is assembled and installed with the main pump steam generator side cold section main pipe end face 9. The steam generator outlet nozzle end face 11 and the main pump steam generator side cold section main pipe end face 9 are staggered by a section of the weld shrinkage between the pressure vessel inlet nozzle end face 2 and the main pump pressure vessel side cold section main pipe end face 6.

[0083] (12) Weld the end face 2 of the inlet nozzle of the pressure vessel to the end face 6 of the main pipeline of the cold section of the main pump pressure vessel.

[0084] (13) After the weld shrinkage of the weld between the pressure vessel inlet nozzle end face 2 and the main pump pressure vessel side cold section main pipeline end face 6, the steam generator outlet nozzle end face 11 and the main pump steam generator side cold section main pipeline end face 9 are aligned and assembled.

[0085] (14) Simultaneously weld the weld between the end face 9 of the main cold section of the main pump steam generator side and the end face 11 of the steam generator outlet nozzle, and the weld between the end face 16 of the hot section main pipeline steam generator side and the end face 15 of the steam generator inlet nozzle, to complete the installation welding of a reactor coolant loop.

[0086] During welding shrinkage, only the steam generator 13 moves. Compared with existing technologies that require the steam generator and both the cold and hot main pipelines to move together, this reduces structural constraint, reduces welding stress, and simplifies construction complexity.

[0087] Example 2:

[0088] like Figure 9 and Figure 10 As shown, the present invention also provides another specific embodiment of the reactor coolant loop, which connects the reactor pressure vessel 1 and the auxiliary main pump steam generator 26 through a hot section main pipe 17 and a cold section main pipe 20. The hot section main pipe 17 is connected between the pressure vessel outlet nozzle 5 and the auxiliary main pump steam generator inlet nozzle 29, and the cold section main pipe 20 is connected between the auxiliary main pump steam generator outlet nozzle 23 and the pressure vessel inlet nozzle 3.

[0089] The pressure vessel side end face 19 and the steam generator side end face 21 of the cold section main pipeline are perpendicular to each other, wherein, as shown in... Figure 5 As shown, the reactor pressure vessel 1 is equipped with a pressure vessel inlet nozzle 3 and a pressure vessel outlet nozzle 5, and the end face 2 of the pressure vessel inlet nozzle and the end face 4 of the pressure vessel outlet nozzle are perpendicular to each other. Figure 11 As shown, the inlet nozzle end face 30 of the main pump casing 28 attached to the main pump steam generator 26 is parallel to the outlet nozzle end face 22 of the main pump casing 24 attached to the main pump steam generator 26.

[0090] As described above, the reactor coolant loop, such as Figure 10 As shown, the axial direction of the main pump impeller and the inlet main pump motor 27 within the inlet main pump casing 28 of the attached main pump steam generator 26 is parallel to the horizontal plane, while the axial direction of the main pump impeller and the outlet main pump motor 25 within the outlet main pump casing 24 of the attached main pump steam generator 26 is perpendicular to the horizontal plane. This axial arrangement of the main pump impeller adopts the same shaft inlet and outlet method as the existing main pump, which can make full use of the existing main pump and hydraulic design to achieve an equivalent pumping effect. Furthermore, the bottom end cap water chamber structure of the attached main pump steam generator can be simplified from one inlet and two outlets to one inlet and one outlet, reducing the number of end cap openings.

[0091] Alternatively, after modifying the hydraulic design to adopt a radial inlet and axial outlet configuration, the axial arrangement of the main pump propeller blades inside the main pump casing 28 and the main pump motor 27 can also be perpendicular to the horizontal plane.

[0092] The reactor coolant loop as described above, wherein, as Figure 10 As shown, during the installation and welding of the main pipeline in the entire loop, the welding positions of the four welds at both ends of the hot section main pipeline 17 and both ends of the cold section main pipeline 20 are all horizontal fixed butt joints.

[0093] Preferably, wherein, Figure 9 Adjustment sections are provided at the ends of the main cold section pipe 20 near the pressure vessel side face 19 and the steam generator side face 21 of the main cold section pipe.

[0094] Furthermore, such as Figure 7 and 8 As shown, a steam generator nozzle shadow body is manufactured. The steam generator nozzle shadow body includes two shadow nozzles 31 corresponding to the outlet nozzle 23 and the inlet nozzle 29 of the main pump steam generator, respectively. The end face dimensions and position dimensions of the two shadow nozzles 31 are consistent with the corresponding dimensions of the end faces 22 and 30 of the nozzles corresponding to the main pump steam generator 26.

[0095] Furthermore, the steam generator nozzle shadow body also includes a shadow body bottom end cap 32 and a shadow body platform 34. The shadow body bottom end cap 32 corresponds to the bottom end cap of the main pump steam generator 26, and the shadow body platform 34 has the same dimensions as the platform supporting the main pump steam generator 26. The shadow body bottom end cap 32 is mounted on the steam generator support 35 through the shadow body platform 34. Two shadow nozzles 31 are set on one side of the shadow body bottom end cap 32, and a counterweight 33 is provided on the other side of the shadow body bottom end cap 32. In specific implementation, the steam generator nozzle shadow body can be made and used by mechanical or electromechanical physical means, or it can be used by making an electronic virtual body using three-dimensional scanning technology.

[0096] Preferably, the reactor coolant loop described above, including the main pump steam generator room 26 and the hot section main pipeline 17 and cold section main pipeline 20, adopts a modular design.

[0097] like Figure 9 and Figure 10 As shown, the installation method of the reactor coolant loop in this embodiment includes the following steps:

[0098] (1) The reactor pressure vessel 1 and the hot section main pipeline 17 are respectively introduced into the installation position and placed in place.

[0099] (2) Install the weld between the outlet nozzle end face 4 of the pressure vessel and the side end face 18 of the hot section main pipeline pressure vessel.

[0100] (3) Figure 7 and Figure 8 As shown, the dimensions and positions of the shadow platform 34 and the shadow nozzle 31 of the steam generator nozzle shadow body are made, adjusted and copied to be the same as the corresponding dimensions of the support platform and nozzle end faces 22 and 30 of the actual main pump steam generator 26. Then, the steam generator nozzle shadow body is installed on the steam generator support 35. This step is equivalent to installing the actual main pump steam generator 26 on the steam generator support 35.

[0101] (4) The steam generator side end face 16 of the hot section main pipeline is assembled and installed with the inlet shadow nozzle 31 end face of the steam generator nozzle shadow body; the data between the outlet shadow nozzle end face of the steam generator nozzle shadow body and the inlet nozzle end face 2 of the pressure vessel are measured, and after correction according to the welding shrinkage of the weld between the pressure vessel inlet nozzle 3 and the cold section main pipeline, the measurement and processing dimensions of the cold section main pipeline 20 installed in step (7) are obtained.

[0102] (5) Based on the measurement and processing dimensions of the cold section main pipe 20 that is suitable for installation obtained in step (4), the pipe end adjustment section of the cold section main pipe 20 is measured and processed to obtain the cold section main pipe 20 that is suitable for installation in step (7).

[0103] (6) The cold section main pipe 20, which has been processed and installed in step (7), is introduced into the installation position.

[0104] (7) Assemble the outlet nozzle end face of the steam generator nozzle shadow body, the cold section main pipeline 20, and the pressure vessel inlet nozzle end face 2; wherein, the outlet nozzle end face of the steam generator nozzle shadow body is offset from the steam generator side end face 21 of the cold section main pipeline by a certain amount of welding shrinkage of the weld between the pressure vessel inlet nozzle end face 2 and the pressure vessel side end face 19 of the cold section main pipeline.

[0105] (8) Installation of the steam generator room and main pipeline room modules.

[0106] (9) Remove the nozzle of the steam generator.

[0107] (10) The main pump steam generator 26 is installed on the steam generator support.

[0108] (11) The main pump steam generator inlet nozzle end face 30 and the hot section main pipeline steam generator side end face 16 are installed together, and the main pump steam generator outlet nozzle end face 22 and the cold section main pipeline steam generator side end face 21 are installed together; wherein, the main pump steam generator outlet nozzle end face 22 and the cold section main pipeline steam generator side end face 21 are staggered by a section to accommodate the welding shrinkage of the weld between the pressure vessel inlet nozzle end face 2 and the cold section main pipeline pressure vessel side end face 19.

[0109] (12) Weld the weld between the end face 2 of the inlet nozzle of the welding pressure vessel and the end face 19 of the side of the cold section main pipeline pressure vessel.

[0110] (13) After the weld between the pressure vessel inlet nozzle end face 2 and the pressure vessel side end face 19 of the cold section main pipeline shrinks, the main pump steam generator outlet nozzle end face 22 and the cold section main pipeline steam generator side end face 21 are aligned and assembled.

[0111] (14) Simultaneously weld the weld between the outlet nozzle end face 22 of the auxiliary main pump steam generator and the side end face 21 of the cold section main pipeline steam generator, and the weld between the side end face 16 of the hot section main pipeline steam generator and the inlet nozzle end face 30 of the auxiliary main pump steam generator, to complete the installation welding of one reactor coolant loop. During welding, this welding shrinkage only moves the auxiliary main pump steam generator 26. Compared with the reference technology where welding shrinkage requires movement of both the steam generator and the main pipeline, this relatively reduces structural constraint, reduces welding stress, and simplifies construction complexity.

[0112] Example 3:

[0113] Under the condition that both the hot section main pipe 17 and the cold section main pipe 20 can be introduced into the main pipe room from the steam generator room, another method for installing the reactor coolant loop as described in Example 2 includes the following steps:

[0114] (1) After the reactor pressure vessel room, steam generator room and main piping room are completed, such as Figure 9 and Figure 10 As shown, reactor pressure vessel 1 and hot section main pipe 17 are respectively introduced into the installation position.

[0115] (2) Install the weld between the outlet nozzle end face 4 of the pressure vessel and the side end face 18 of the hot section main pipeline pressure vessel.

[0116] (3) Figure 7 and Figure 8 As shown, the dimensions and positions of the shadow platform 34 and the shadow nozzle 31 of the steam generator nozzle shadow body are made, adjusted and copied to be the same as the corresponding dimensions of the support platform and nozzle end faces 22 and 30 of the actual main pump steam generator 26. Then, the steam generator nozzle shadow body is installed on the steam generator support 35. This step is equivalent to installing the actual main pump steam generator 26 on the steam generator support 35.

[0117] (4) The steam generator side end face 16 of the hot section main pipeline is assembled and installed with the inlet shadow nozzle 31 end face of the steam generator nozzle shadow body; the data between the outlet shadow nozzle end face of the steam generator nozzle shadow body and the inlet nozzle end face 2 of the pressure vessel is measured and corrected to obtain the appropriate measurement and processing dimensions of the cold section main pipeline 20 installed in step (9).

[0118] (5) Based on the measurement and processing dimensions of the cold section main pipe 20 that is suitable for installation obtained in step (4), the pipe end adjustment section of the cold section main pipe 20 is measured and processed to obtain the cold section main pipe 20 that is suitable for installation in step (9).

[0119] (6) Remove the nozzle of the steam generator.

[0120] (7) The cold section main pipe 20 installed in step (9) is placed in the installation position.

[0121] (8) The main pump steam generator 26 is installed on the steam generator support.

[0122] (9) The main pump steam generator inlet nozzle end face 30 and the hot section main pipeline steam generator side end face 16 are installed together, and the main pump steam generator outlet nozzle end face 22 and the cold section main pipeline steam generator side end face 21 are installed together; wherein, the main pump steam generator outlet nozzle end face 22 and the cold section main pipeline steam generator side end face 21 are staggered by a section to accommodate the welding shrinkage of the weld between the pressure vessel inlet nozzle end face 2 and the cold section main pipeline pressure vessel side end face 19.

[0123] (10) Weld the weld between the end face 2 of the inlet nozzle of the welding pressure vessel and the end face 19 of the side of the cold section main pipeline pressure vessel.

[0124] (11) After the weld between the pressure vessel inlet nozzle end face 2 and the pressure vessel side end face 19 of the cold section main pipeline shrinks, the main pump steam generator outlet nozzle end face 22 and the cold section main pipeline steam generator side end face 21 are aligned and assembled.

[0125] (12) Simultaneously weld the weld between the outlet nozzle end face 22 of the main pump steam generator and the side end face 21 of the cold section main pipeline steam generator, and the weld between the side end face 16 of the hot section main pipeline steam generator and the inlet nozzle end face 30 of the main pump steam generator, completing the installation welding of one reactor coolant loop. The beneficial effect of Example 3 is that there is no installation required in Examples 1 and 2, and the civil engineering work is carried out simultaneously, which is more conducive to ensuring the installation quality.

[0126] Example 4:

[0127] Based on Examples 1, 2, and 3, as follows Figure 12 , 13 and Figure 14 As shown, a specific embodiment of the present invention provides a reactor coolant loop in which the reactor pressure vessel outlet nozzle end face 4 and the reactor pressure vessel inlet nozzle end face 2 are parallel to each other, and are also parallel to the steam generator inlet nozzle end face and outlet nozzle end face.

[0128] Among them, such as Figure 14 and 15 As shown, each of the hot section main pipeline and the cold section main pipeline is equipped with a main pump 8, and the main pump casing of the main pump pressure vessel side main pipeline 7, the main pump steam generator side main pipeline 10 and the main pump 8 are prefabricated as an integrated structure. This setting can utilize the existing main pump design to achieve the purpose of increasing pumping capacity and increasing the capacity of the nuclear power unit.

[0129] Preferably, the main pump 8 is positioned off-center from the center line connecting the reactor pressure vessel and the steam generator, which reduces the distance between the reactor pressure vessel 1 and the steam generator 13, making the reactor coolant loop more compact. Adjustment sections are provided at the ends of the hot-section main pipe and the cold-section main pipe. During the installation and welding of the main pipes in the entire loop, the welding positions of the four welds at both ends of the hot-section main pipe and the cold-section main pipe are all horizontal fixed butt joints.

[0130] The pressure vessel outlet nozzle 5 is welded to the pressure vessel side main pipeline 7 of the main pump via the pressure vessel outlet nozzle end face 4 and the pressure vessel side end face 18 of the hot section main pipeline. The pressure vessel inlet nozzle 3 is welded to the pressure vessel side main pipeline 7 of the main pump via the pressure vessel inlet nozzle end face 2 and the cold section main pipeline end face 6 of the main pump via the pressure vessel side. The steam generator inlet nozzle 14 is welded to the steam generator side main pipeline 10 of the main pump via the steam generator inlet nozzle end face 15 and the steam generator side end face 16 of the hot section main pipeline. The steam generator outlet nozzle 12 is welded to the main pump side main pipeline 10 of the cold section main pipeline via the cold section main pipeline end face 9 and the steam generator outlet nozzle end face 11 of the main pump via the steam generator side. The pressure vessel outlet nozzle end face 4 and the pressure vessel inlet nozzle end face 2 are parallel to each other, and are also parallel to the steam generator inlet nozzle end face 15 and the steam generator outlet nozzle end face 11.

[0131] like Figure 10 and 12 As shown, the hot section main pipe 17 and the cold section main pipe 20 are connected to... Figure 13 The reactor pressure vessel 1 shown is Figure 11 As shown, between the main pump steam generator 26 and the pressure vessel outlet nozzle 5, the pressure vessel outlet nozzle end face 4 is welded to the pressure vessel side end face 18 of the hot section main pipeline to connect with the hot section main pipeline 17. The pressure vessel inlet nozzle 3 is welded to the pressure vessel inlet nozzle end face 2 and the pressure vessel side end face 19 of the cold section main pipeline to connect with the cold section main pipeline 20. The main pump steam generator inlet nozzle 29 is welded to the hot section main pipeline 17 via the main pump steam generator inlet nozzle end face 30 and the hot section main pipeline steam generator side end face 16. The main pump steam generator outlet nozzle 23 is welded to the cold section main pipeline 20 via the main pump steam generator outlet nozzle end face 22 and the cold section main pipeline steam generator side end face 21.

[0132] The pressure vessel outlet nozzle end face 4 and the pressure vessel inlet nozzle end face 2 are parallel to each other, and are also parallel to the main pump steam generator inlet nozzle end face 30 and the main pump steam generator outlet nozzle end face 22. During the installation and welding of the main pipeline of the entire loop, the welding positions of the four welds at both ends of the hot section main pipeline 17 and both ends of the cold section main pipeline 20 are all horizontal fixed butt joints.

[0133] The installation methods for the two reactor coolant loops described above specifically include the following steps:

[0134] like Figure 10 and Figure 12 As shown, or as Figure 14 and Figure 15 As shown,

[0135] (1) Reactor pressure vessel 1 is introduced into the installation position.

[0136] (2) Nozzle shadow body manufacturing and installation steps: After the dimensions and position of the platform, nozzle end face and the nozzle shadow body of the steam generator 13 or the steam generator with main pump 26 are made, adjusted and copied to be the same as the corresponding dimensions of the actual steam generator platform and nozzle, the nozzle shadow body of the steam generator 13 or 26 is installed on the steam generator support 35.

[0137] (3) Figure 12 The measurements shown are of the nozzle end faces of the main pump steam generator 26, including the inlet and outlet nozzle end faces, and the inlet nozzle end face 2 and outlet nozzle end face 4 of the pressure vessel.

[0138] Or such as Figure 14 The figures shown are of the inlet and outlet nozzle faces of the steam generator 13, and the inlet nozzle face 2 and outlet nozzle face 4 of the pressure vessel.

[0139] (4) Based on the measurement data between the inlet and outlet nozzle end faces of the main pump steam generator 26 and the inlet nozzle end face 2 and outlet nozzle end face 4 of the pressure vessel, the pipe end adjustment section of the hot section main pipeline 17 and the cold section main pipeline 20 is measured and processed.

[0140] Or such as Figure 14 The measurement data between the inlet and outlet nozzle end faces of the steam generator 13 and the inlet nozzle end face 2 and outlet nozzle end face 4 of the pressure vessel are used as a reference to measure and process the pipe end adjustment section of the main pipeline 7 on the pressure vessel side of the main pump and the main pipeline 10 on the steam generator side of the main pump.

[0141] (5) Steps for removing the nozzle shadow body: Remove the nozzle shadow body of the steam generator.

[0142] (6) Post-processing positioning steps: After measuring and processing the hot section main pipeline and the cold section main pipeline, introduce them into the installation position and position them.

[0143] (7) Figure 12 As shown, the hot section main pipeline pressure vessel side end face 18 is connected to the pressure vessel outlet nozzle end face 4, and the cold section main pipeline pressure vessel side end face 19 is connected to the pressure vessel inlet nozzle end face 2.

[0144] Or such as Figure 14 As shown, the main pump is installed with the cold section main pipe end face 6 on the pressure vessel side and the pressure vessel inlet nozzle end face 2, and the hot section main pipe pressure vessel side end face 18 on the pressure vessel side and the pressure vessel outlet nozzle end face 4.

[0145] (8) Construction of the steam generator room and main pipeline room.

[0146] (9) Steam generator 13 or steam generator 26 with main pump is introduced into the installation position.

[0147] (10) such as Figure 12 As shown, the hot section main pipeline steam generator side end face 16, the cold section main pipeline steam generator side end face 21, the main pump steam generator inlet nozzle end face 30, and the main pump steam generator outlet nozzle end face 22 are assembled and installed.

[0148] Or such as Figure 14 As shown, the hot section main pipeline steam generator side end face 16, the main pump steam generator side cold section main pipeline end face 9, the steam generator inlet nozzle end face 15, and the steam generator outlet nozzle end face 11 are assembled and installed.

[0149] (11) such as Figure 12 As shown, the welds are simultaneously and evenly welded between the inlet nozzle end face 30 of the main pump steam generator and the side end face 16 of the hot section main pipeline steam generator, between the outlet nozzle end face 22 of the main pump steam generator and the side end face 21 of the cold section main pipeline steam generator, between the inlet nozzle end face 2 of the pressure vessel and the pressure vessel side end face 19 of the cold section main pipeline, and between the outlet nozzle end face 4 of the pressure vessel and the pressure vessel side end face 18 of the hot section main pipeline, thus completing the installation welding of one reactor coolant loop.

[0150] Or such as Figure 14 As shown, the welds are simultaneously and evenly applied to the steam generator inlet nozzle end face 15 and the hot section main pipeline steam generator side end face 16, the steam generator outlet nozzle end face 11 and the main pump steam generator side cold section main pipeline end face 9, the pressure vessel inlet nozzle end face 2 and the main pump pressure vessel side cold section main pipeline end face 6, and the pressure vessel outlet nozzle end face 4 and the hot section main pipeline pressure vessel side end face 18, thus completing the installation welding of one reactor coolant loop.

[0151] The balanced welding described above aims to minimize the difference in welding shrinkage between welds by applying welding symmetrically, monitoring welding heat input and welding deformation, and so as to avoid generating excessive welding stress.

[0152] Compared to the reference technology, which requires multiple steps to complete the installation and welding of a reactor coolant loop, this solution can complete the installation and welding of a reactor coolant loop in one step, significantly improving construction efficiency.

[0153] In summary, it can be seen from the above description that the embodiments of the present invention achieve the following technical effects:

[0154] 1. This invention employs a steam generator with parallel inlet and outlet nozzle ends, a reactor pressure vessel with perpendicular inlet and outlet nozzle ends, and a dedicated main pump setup. Furthermore, during the installation and welding of the main pipeline in the entire loop, the welding positions of the four welds at both ends of the hot section main pipeline connecting the reactor pressure vessel and the steam generator, as well as at both ends of the cold section main pipeline, are all horizontally fixed butt joints. This simplifies the reactor coolant loop structure and allows the closed-loop installation welds to be located at the coolant outlet nozzle and coolant inlet nozzle of the steam generator. During closed-loop installation welding shrinkage, only the steam generator needs to be moved, not the main pipeline, further reducing structural constraint and welding stress.

[0155] 2. The reactor coolant loop installation method of the present invention, by designing and installing the steam generator nozzle shadow body, is equivalent to installing the actual steam generator in the designated position. This allows for the pre-measurement of the relevant dimensional data of the adjustment sections at both ends of the main pipeline, ensuring that the steam generator can be precisely aligned with the main pipeline, thus avoiding additional on-site measurement and processing space and transportation.

[0156] 3. When the reactor coolant loop of the present invention adopts a reactor pressure vessel with parallel inlet and outlet nozzle end faces, the installation welds of each loop can be optimized from multiple sequential welding steps to one simultaneous welding step, thereby greatly improving construction efficiency.

[0157] 4. The embodiments of the present invention simplify the reactor coolant loop structure and the installation and construction process and complexity, which helps to reduce costs, shorten the construction period, and improve the safety and economy of nuclear power plant construction and operation.

[0158] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A reactor coolant loop, comprising a reactor pressure vessel and a steam generator, wherein the reactor pressure vessel includes a pressure vessel outlet nozzle and a pressure vessel inlet nozzle, the steam generator includes a steam generator inlet nozzle and a steam generator outlet nozzle, and the reactor coolant loop further includes a main pipeline, wherein the main pipeline includes a hot section main pipeline connecting the pressure vessel outlet nozzle and the steam generator inlet nozzle, and a cold section main pipeline connecting the steam generator outlet nozzle and the pressure vessel inlet nozzle; Its features are: The inlet nozzle face and outlet nozzle face of the steam generator are parallel to each other, and the inlet nozzle face and outlet nozzle face of the pressure vessel are perpendicular or parallel to each other, with the outlet nozzle face of the pressure vessel parallel to the inlet nozzle face of the steam generator; and when the main pipeline of the reactor coolant loop is installed and welded, the welding positions of the four welds at both ends of the hot section main pipeline and both ends of the cold section main pipeline are all horizontal fixed butt joints.

2. The reactor coolant loop according to claim 1, characterized in that: The reactor coolant loop also includes a main pump, and the hot section main pipe and / or the cold section main pipe are prefabricated as an integral structure with the pump casing of the main pump; Alternatively, the main pump may be located at the bottom of the steam generator to form a steam generator with an attached main pump.

3. The reactor coolant loop according to claim 2, characterized in that: The steam generator with auxiliary main pump includes an inlet main pump and an outlet main pump. The inlet main pump includes an inlet main pump casing and an inlet main pump motor. The outlet main pump includes an outlet main pump casing and an outlet main pump motor. The axial direction of the impeller in the inlet main pump casing and the axial direction of the inlet main pump motor are parallel or perpendicular to the horizontal plane. The axial direction of the impeller in the outlet main pump casing and the axial direction of the outlet main pump motor are perpendicular to the horizontal plane.

4. The reactor coolant loop according to any one of claims 1-3, characterized in that: The main pipeline is equipped with an adjustment section at its end.

5. The reactor coolant loop according to claim 2, characterized in that: During the installation of the reactor coolant loop, the equipment used includes a steam generator nozzle shadow body, which includes two shadow nozzles corresponding to the steam generator inlet nozzle and the steam generator outlet nozzle, respectively. The end face dimensions and position dimensions of the two shadow nozzles are consistent with the dimensions of the corresponding nozzles of the steam generator.

6. The reactor coolant loop according to claim 5, characterized in that: The steam generator nozzle shadow body also includes a shadow body bottom end cap and a shadow platform. The shadow body bottom end cap corresponds to the bottom end cap of the steam generator, and the shadow platform has the same size as the platform supporting the steam generator. The steam generator nozzle shadow body is mounted on the steam generator support through the shadow platform of the shadow body bottom end cap.

7. A method for installing a reactor coolant loop, characterized in that, For installing a reactor coolant loop according to any one of claims 1-6, the installation method comprises the following steps: The steps for manufacturing and installing the nozzle shadow body are as follows: manufacture the steam generator nozzle shadow body according to the steam generator, and install the steam generator nozzle shadow body on the steam generator support; The measurement and processing steps involve measuring and processing the adjustment section at the end of the main pipeline, based on the measurement data of the shadow nozzle of the steam generator nozzle body and the nozzle of the reactor pressure vessel that is installed in place. The post-processing and placement step involves measuring and placing the processed main pipeline into the installation position. The nozzle removal step involves removing the steam generator nozzle from the steam generator support. Steam generator installation steps: The steam generator is introduced into the installation position and positioned on the steam generator support; Installation steps for the main pipeline assembly: assembling and installing the steam generator nozzle, pressure vessel nozzle, and the main pipeline assembly. The welding process involves welding the nozzle to the main pipe.

8. The installation method according to claim 7, characterized in that: When the inlet nozzle end face and the outlet nozzle end face of the pressure vessel are perpendicular to each other, the installation method includes the following steps: Before the measurement and processing steps, the reactor pressure vessel and the hot section main pipeline are introduced into the installation position and welded between the end face of the pressure vessel outlet nozzle and the end face of the hot section main pipeline pressure vessel. In the measurement and processing step, after assembling and installing the steam generator side end face of the hot section main pipeline with the inlet shadow nozzle of the steam generator nozzle shadow body, the adjustment section at the end of the cold section main pipeline is measured and processed based on the measurement data of the outlet shadow nozzle of the steam generator nozzle shadow body and the inlet nozzle of the pressure vessel, and after correction according to the welding shrinkage of the weld between the pressure vessel inlet nozzle and the cold section main pipeline. After the processing and positioning step, the two ends of the cold section main pipe are respectively paired and installed with the outlet nozzle of the steam generator nozzle body and the inlet nozzle of the pressure vessel. The end face of the outlet nozzle of the steam generator nozzle body is offset from the end face of the cold section main pipe by a certain amount of welding shrinkage of the weld between the pressure vessel inlet nozzle and the cold section main pipe.

9. The installation method according to claim 8, characterized in that: The installation method also includes the following steps: In the main pipe assembly installation step, the end face of the steam generator outlet nozzle is offset from the end face of the cold section main pipe by a certain amount to account for the welding shrinkage of the weld between the pressure vessel inlet nozzle and the cold section main pipe. In the welding step, the weld between the pressure vessel inlet nozzle and the cold section main pipeline is welded first. After the weld shrinks, the end face of the steam generator outlet nozzle is aligned with the end face of the cold section main pipeline. Then, the welds between the steam generator inlet nozzle and the hot section main pipeline, and between the steam generator outlet nozzle and the cold section main pipeline are welded simultaneously.

10. The installation method according to claim 7, characterized in that: Prior to the steam generator installation step, there are also construction steps for the main piping room and the steam generator room.

11. The installation method according to claim 7, characterized in that: When the inlet nozzle end face and the outlet nozzle end face of the pressure vessel are parallel to each other, the installation method includes the following steps: In the measurement and processing step, based on the measurement data of the shadow nozzle of the steam generator nozzle body and the inlet and outlet nozzles of the reactor pressure vessel installed in place, the adjustment sections at the ends of the hot section main pipe and the cold section main pipe are measured and processed respectively; in the nozzle main pipe assembly and installation step, the cold section main pipe and the hot section main pipe are first assembled and installed with the inlet and outlet nozzles of the reactor pressure vessel, and then the cold section main pipe and the hot section main pipe are assembled and installed with the inlet and outlet nozzles of the steam generator; in the welding step, the four welds between the ends of the hot section main pipe and the cold section main pipe and the inlet and outlet nozzles of the reactor pressure vessel and the inlet and outlet nozzles of the steam generator are simultaneously and evenly welded.

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