Passive steam generator secondary side residual heat removal system

Abstract

The invention relates to a passive steam generator secondary side waste heat removal system which comprises a first pipe base, a first pipeline, a condenser and a second pipeline, the condenser is in fluid communication with the first pipeline and the second pipeline, the first pipeline is connected to a main steam pipeline of a steam generator through the first pipe base, and the second pipeline is connected to a second steam pipeline of the steam generator through the second pipe base. The second pipeline is connected with a main water supply pipeline of the steam generator, the first pipe base is of a hollow structure and comprises an inlet end and an outlet end, the outlet end is the side, connected to the main steam pipeline of the steam generator, of the first pipe base, and the inlet end is connected with the outlet end. The inlet end is the side, connected to the first pipeline, of the first pipe base, the wall thickness, close to the inlet end, of the first pipe base is larger than the wall thickness, close to the outlet end, of the first pipe base, the first pipe base and the main steam pipeline are connected in a curved surface transition mode, collapse deformation and cracking at the connecting position of the system pipelines can be effectively prevented, and the service life of the system pipelines is prolonged. And the working stability of the system is improved.

Description

Technical Field

[0001] The present application relates to a passive secondary side waste heat removal system, and in particular, to a passive steam generator secondary side waste heat removal system. Background Art

[0002] The existing steam generator secondary side waste heat removal usually adopts an active method. When the off-site power and on-site power supply are lost, the heat on the secondary side of the steam generator cannot be discharged, which will cause heat accumulation in the core and even cause serious consequences such as core melting.

[0003] In order to improve the safety of nuclear power plants, ensure that the nuclear power plants can still be safely shut down in the event of a loss of power inside or outside the plant, or remove the residual heat from the core in the event of an accident to ensure the safety of the reactor, the passive secondary side residual heat removal system in the prior art utilizes the physical properties of the heat transfer medium's own gravity to remove the heat from the secondary side of the steam generator without the support of an external power source, thereby achieving the effect of reducing the heat of the core. For example, CN105957567B discloses a non-active secondary side waste heat removal system for a steam generator, the system comprising: a heat exchanger, the heat exchanger being placed in a cooling water tank, one end of a condensate pipe being connected to a lower head of the heat exchanger, and the other end being connected to a main water supply pipe of the steam generator; one end of a steam pipeline being connected to an upper head of the heat exchanger, and the other end being connected to a steam outlet of the steam generator; N make-up water tanks, the upper part of which is connected to the steam pipeline, and the lower part of which is connected to the condensate pipe; and M air coolers, the evaporation section of the air cooler being arranged in the cooling water tank, and the condensation section of the air cooler being arranged in the atmosphere outside the cooling water tank, thereby achieving the effect of discharging heat from the secondary side of the steam generator under non-active conditions. For another example, CN116417170A discloses a passive secondary side residual heat removal system, which serves as a dedicated safety facility to perform the function of extracting the core residual heat after an accident. It operates in a natural circulation mode, and the steam generated in the steam generator is condensed through a PRS heat exchanger and then injected into the steam generator again through a water feed pipeline. The core energy is removed through the steam generator, thereby ensuring the safety of the nuclear power plant.

[0004] However, in the case of an accident, the heat transfer pipes of the condenser are very likely to rupture due to the impact caused by the sudden opening of the valve and the rapid thermal expansion and contraction, which reduces the stability of the system. There are also problems such as the lack of maintenance platform and the difficulty in discharging the heat transfer medium, as well as the lack of inspection of the water tank and the inability to purify the heat transfer medium. In addition, these existing technologies mainly propose technical solutions from the perspective of system professionals, and lack technical solutions that can be achieved through professional layout. Summary of the invention

[0005] The present application provides a passive steam generator secondary side waste heat removal system from the perspective of layout expertise, which is used to improve the stability of the operation of the steam generator secondary side waste heat removal system.

[0006] To achieve the above-mentioned purpose, according to one aspect of the present application, a passive steam generator secondary side waste heat removal system is provided, comprising a first tube seat, a first pipeline, a condenser and a second pipeline, wherein the condenser is fluidically connected to the first pipeline and the second pipeline, wherein the fluidic connection refers to connecting different containers or devices through pipes, pipelines, etc., so as to realize the transmission and distribution of fluids such as gas or liquid; in such a connected system, fluids such as gas or liquid can flow from one container to another container or from one device to another device under the action of pressure difference, wherein the first pipeline is connected to the main steam pipeline of the steam generator through the first tube seat, and the second pipeline is connected to the main water supply pipeline of the steam generator, wherein the first tube seat is a hollow structure, wherein the first tube seat comprises an inlet end and an outlet end, wherein the outlet end is a side of the first tube seat connected to the main steam pipeline of the steam generator, and the inlet end is a side of the first tube seat connected to the first pipeline, wherein the wall thickness of the first tube seat near the inlet end is greater than the wall thickness near the outlet end, and the connection between the first tube seat and the main steam pipeline is a curved surface transition.

[0007] Furthermore, at least 85% of the axial length of the first tube seat from the inlet end to the outlet end is a tubular inner cavity with a constant inner diameter, and at most 15% of the axial length of the first tube seat from the outlet end to the inlet end has an inner diameter greater than the inner diameter of the tubular inner cavity.

[0008] Furthermore, the first pipeline includes a U-shaped water seal, and the length from the U-shaped water seal to the connection end of the first pipeline and the condenser accounts for at most 10% of the entire length of the first pipeline.

[0009] Furthermore, both ends of the U-shaped water seal are local highest points, the local highest points are inflection points near the end points of the U-shaped water seal, exhaust ports are provided at the local highest points, and a drain port is provided at the bottom of the U-shaped water seal.

[0010] Furthermore, the local highest point of the U-shaped water seal in the first pipeline is higher than the entire first pipeline, the first pipe seat is lower than the entire first pipeline, and the connection end of the second pipeline 10 and the condenser is higher than the entire second pipeline.

[0011] Furthermore, when the passive secondary side waste heat removal system is working, in at least 90% of the length of the first pipeline, the heat transfer medium moves in a direction to overcome gravity, and in at least 90% of the length of the second pipeline, the heat transfer medium does not move in a direction to overcome gravity.

[0012] Furthermore, the passive steam generator secondary side waste heat removal system also includes a water make-up tank, the water inlet of the water make-up tank is fluidly connected to the first pipeline, the water outlet is fluidly connected to the second pipeline, and the water make-up tank is also provided with an exhaust port and a drain port.

[0013] Furthermore, it also includes a second tube seat, which is fluidically connected to the main water supply pipe of the steam generator and one end of the second pipeline respectively, and the second tube seat includes a tubular inner cavity with a constant inner diameter along the axial direction, and the connection between the second tube seat and the main water supply pipe is a curved transition.

[0014] Furthermore, it also includes a heat exchange water tank, which is higher than the steam generator to form a height difference. The condenser is arranged at the bottom of the heat exchange water tank, and the heat exchange water tank is provided with an exhaust port.

[0015] Furthermore, it also includes a circulating purification pipeline, and the condenser and the heat exchange water tank are provided with the circulating purification pipeline.

[0016] Furthermore, it also includes a penetration piece, which is a hollow structure. The first pipeline and the second pipeline pass through the containment shell through the penetration piece and are fluidly connected with the main steam pipeline and the main feedwater pipeline respectively.

[0017] Furthermore, it also includes an anti-swinging member, which includes a frame with oblique supports and is arranged near the place where the first pipeline and / or the second pipeline passes through the containment shell, and at least part of the anti-swinging member is located between the containment shell and the first pipeline and / or the second pipeline.

[0018] Furthermore, the first pipeline also includes a radiation monitoring instrument.

[0019] Furthermore, it also includes a water tank leakage monitoring pipeline, and the water tank leakage monitoring pipeline is arranged between the water exchange water tank and the wall.

[0020] Furthermore, maintenance platforms are provided inside the water exchange tank and outside the condenser.

[0021] By applying the above technical solution of the present invention, at least the following technical effects are achieved:

[0022] 1. The first pipe seat designed is used for connecting the first pipeline with the seat of the main steam pipe of the steam generator, which can effectively prevent the collapse, deformation and cracking of the connection under the external force caused by the displacement of the main steam pipe and the evaporator, thereby improving the working stability of the secondary side waste heat removal system of the passive steam generator.

[0023] 2. The passive secondary side residual heat removal system and related designs ensure that in the event of a beyond-design basis accident, only gravity and other non-energy physical properties are relied upon to form a passive natural circulation in the circulation pipe system, taking away the heat in the steam generator and the heat in the core, avoiding the risk of core melting.

[0024] 3. The designed U-shaped water seal reduces the impact of the heat transfer medium on the condenser and other downstream equipment, prevents damage to the equipment, and improves system stability. The drain and exhaust ports designed in the U-shaped water seal, heat exchange water tank, and water supply tank ensure that water can be drained and exhausted in time when repairing the equipment.

[0025] 4. The designed water replenishment tank can replenish the heat transfer medium in time when the heat transfer medium is insufficient, ensuring the normal operation of the passive secondary side waste heat removal system. The water tank leakage monitoring pipeline is designed between the water exchange water tank and the concrete wall to ensure real-time detection of the integrity of the water tank.

[0026] 5. The circulating purification pipelines designed in the condenser, water supply tank and heat exchange water tank ensure the cleanliness of the heat transfer medium in the system. The radiation detector designed in the first pipeline ensures the real-time detection of the radioactive material content of the heat transfer medium in the water tank.

[0027] 6. The designed second pipe seat is used for connecting the second pipeline with the main water supply pipe of the steam generator, which can effectively prevent the cracking of the connection under the action of external force, and improve the working stability of the secondary side waste heat removal system of the passive steam generator.

[0028] 7. Anti-swing parts are designed to prevent pipeline rupture and swing against the steel lining of the containment. The maintenance platform designed outside the heat exchange water tank and condenser ensures convenient system maintenance.

[0029] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 A schematic diagram of the structure of a passive steam generator secondary side waste heat removal system is presented;

[0032] Figure 2 A structural schematic diagram of a first tube socket is presented;

[0033] Figure 3 A structural schematic diagram of a second tube holder is presented;

[0034] Figure 4 A schematic diagram of the structure of an anti-throwing component is presented;

[0035] Figure 5 A structural schematic diagram of a U-shaped water seal is shown.

[0036] Figure numerals: 1. steam generator; 2. main steam pipe; 3. first pipe seat; 4. first pipeline; 5. anti-swinging member; 6. penetration piece; 7. U-shaped water seal; 8. drain port; 9. condenser; 10. second pipeline; 11. second pipe seat; 12. main water supply pipe; 13. make-up water tank; 14. heat exchange water tank. DETAILED DESCRIPTION

[0037] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0038] The present invention is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed by the present invention.

[0039] Example 1

[0040] like Figure 1 As shown, this embodiment proposes a passive steam generator secondary side waste heat removal system, including a first tube seat 3, a first pipeline 4, a condenser 9 and a second pipeline 10, the condenser 9 is fluidly connected to the first pipeline 4 and the second pipeline 10, the first pipeline 4 is connected to the main steam pipe 2 of the steam generator 1 through the first tube seat 3, the second pipeline 10 is connected to the main feed water pipe 12 of the steam generator 1, the first tube seat 3 is a hollow structure, the first tube seat 3 includes an inlet end and an outlet end, the outlet end is a side of the first tube seat 3 connected to the main steam pipe 2 of the steam generator 1, the inlet end is a side of the first tube seat 3 connected to the first pipeline 4, the wall thickness of the first tube seat 3 near the inlet end is greater than the wall thickness near the outlet end, and the connection between the first tube seat 3 and the main steam pipe 2 is a curved surface transition.

[0041] Specifically, Figure 2 As shown, the first tube seat 3 is a non-standard designed tube seat, which adopts a special cone design. The first tube seat is a tubular inner cavity with a constant inner diameter, and a groove is designed at the outlet end. This design is to improve the strength of the connection between the first tube seat 3 and the first pipeline 4 to prevent collapse, deformation or rupture of the connection.

[0042] The connection between the first tube seat 3 and the main steam pipe 2 is a curved surface transition. Specifically, the curved surface transition makes the wall thickness of the first tube seat located at the inlet end the maximum value of the wall thickness of the first tube seat; along the direction from the outlet end to the inlet end, the curved surface transition makes the outer surface of the first tube seat gradually increase in its tendency to extend outward.

[0043] According to this embodiment, the connection between the main steam pipe 2 of the steam generator 1 and the first pipeline 4 in the passive steam generator secondary side waste heat removal system is more solid, and the equipment in the first pipeline 4 and the main steam pipe 2 are not prone to collapse, deformation or cracking under the action of displacement and / or thermal expansion and contraction, which can greatly improve the stability of the passive steam generator secondary side waste heat removal system. The arc-shaped transition between the first pipe seat 3 and the main steam pipe 2 is conducive to non-destructive testing of the welds at the connection.

[0044] Example 2

[0045] like Figure 1 As shown, this embodiment proposes a passive steam generator secondary side waste heat removal system, including a first pipe seat 3, a first pipeline 4, an anti-swinging member 5, a penetration member 6, a U-shaped water seal 7, a drain port 8, a condenser 9, a second pipeline 10, a second pipe seat 11, a water supply tank 13, a heat exchange water tank 14, a circulating purification pipeline, a water tank leakage monitoring pipeline, a radiation detector and a maintenance platform, the first pipeline 4 and the second pipeline 10 are fluidly connected, the first pipeline 4 is connected to the main steam pipeline 2 of the steam generator 1 through the first pipe seat 3, the second pipeline 10 is connected to the main water supply pipeline 12 of the steam generator 1, the first pipe seat 3 is a hollow structure, the first pipe seat 3 includes an inlet end and an outlet end, the outlet end is a side of the first pipe seat 3 connected to the main steam pipeline 2 of the steam generator 1, the inlet end is a side of the first pipe seat 3 connected to the first pipeline 4, the wall thickness of the first pipe seat 3 near the inlet end is greater than the wall thickness near the outlet end, and the connection between the first pipe seat 3 and the main steam pipeline 2 is a curved surface transition.

[0046] Specifically, Figure 2 As shown, the first tube seat 3 is a non-standard design tube seat, which adopts a conical design. The first tube seat 3 is a tubular inner cavity with a constant inner diameter, and a groove is designed at the outlet end. This design is to improve the strength of the connection between the first tube seat 3 and the first pipeline 4 to prevent collapse, deformation or rupture at the connection. The curved surface transition is a circular arc transition, which is conducive to non-destructive testing of the weld at the connection.

[0047] In other embodiments, 85% of the axial length of the first tube seat 3 from the inlet end to the outlet end is a tubular inner cavity with a constant inner diameter, and the inner diameter of 15% of the axial length of the first tube seat 3 from the outlet end to the inlet end is greater than the inner diameter of the tubular inner cavity.

[0048] The connection between the first tube seat 3 and the main steam pipe 2 is a curved surface transition. Specifically, the curved surface transition makes the wall thickness of the first tube seat located at the inlet end the maximum value of the wall thickness of the first tube seat; along the direction from the outlet end to the inlet end, the curved surface transition makes the outer surface of the first tube seat gradually increase in its tendency to extend outward.

[0049] The first pipeline also includes a U-shaped water seal 7. The U-shaped water seal 7 is provided to reduce the impact of the medium (such as water vapor) in the first pipeline 4 on the heat exchange tube of the condenser 9 when the valve is suddenly opened, thereby preventing damage to the equipment and improving system stability.

[0050] like Figure 5 As shown, the two ends of the U-shaped water seal 7 are local highest points, and the local highest points are inflection points near the end points of the U-shaped water seal 7. An exhaust port is provided at the local highest point, and a drain port 8 is provided at the bottom of the U-shaped water seal to facilitate exhaust and draining during maintenance.

[0051] The local highest point of the U-shaped water seal 7 in the first pipeline 4 is higher than the entire first pipeline 4 , the first pipe seat 3 is lower than the entire first pipeline 4 , and the connecting end of the second pipeline 10 and the condenser 9 is higher than the entire second pipeline 10 .

[0052] In other embodiments, the length from the U-shaped water seal 7 to the connection end of the first pipeline 4 and the condenser 9 accounts for at most 10% of the entire length of the first pipeline 4 .

[0053] The water inlet of the water supply tank 13 is fluidly connected to the first pipeline 4, and the water outlet is fluidly connected to the second pipeline 10. When the heat transfer medium (such as water, water vapor) is insufficient, the heat transfer medium (such as water) can be replenished in time to ensure the normal operation of the passive secondary side waste heat removal system. The water supply tank 13 is provided with an exhaust port and a drain port to facilitate exhaust and drainage during maintenance.

[0054] The heat exchange water tank 14 is in a "T" shape, and the condenser 9 is arranged at the bottom of the heat exchange water tank 14, and the minimum liquid level of the heat exchange water tank 14 is ensured to be high enough to submerge the condenser 9, and a certain height difference is maintained between the heat exchange water tank 14 and the port of the main steam pipe 2. Specifically, the condenser 9 is a multi-heat exchange pipe with a thin wall and a "C" shape design, and is provided with a U-shaped exhaust port for easy exhaust during maintenance.

[0055] The condenser 9 and the heat exchange water tank 14 are provided with the circulating purification pipeline. Specifically, the drain port of the heat exchange water tank 14 and the return pipeline of the circulating purification are combined into one, and the return pipeline of the circulating purification is used to drain the water in the heat exchange water tank during maintenance.

[0056] When the passive secondary side waste heat removal system is working, in at least 90% of the length of the first pipeline 4, the heat transfer medium (such as water vapor) moves in the direction of overcoming gravity, and in at least the length of the second pipeline 10, the heat transfer medium (such as water vapor) moves toward the evaporator by gravity. Specifically, from the port of the main steam pipeline 2 to the port of the condenser 9 connected to the first pipeline 4, the first pipeline 4 has an upward trend, and from the port of the condenser 9 connected to the second pipeline 10 to the port of the main water supply pipeline 12, the second pipeline 10 has a downward trend, so as to ensure that the heat transfer medium can achieve natural circulation in the pipeline.

[0057] like Figure 4 As shown, the first pipeline 4 and the second pipeline 10 pass through the containment shell through a penetration piece and are fluidly connected to the main steam pipe 2 and the main water supply pipe 12 respectively. The penetration piece is a hollow structure, and an anti-swinging member 5 with an obliquely supported frame structure is arranged near the place where the first pipeline 4 and the second pipeline 10 pass through the containment shell.

[0058] like Figure 3 As shown, the second tube seat 11 is fluidly connected to the main water supply pipe 12 of the steam generator 1 and one end of the second pipeline 10 respectively, the second tube seat 11 includes a tubular inner cavity with a constant inner diameter along the axial direction, and the connection between the second tube seat 11 and the main water supply pipe 12 is a curved surface transition. Specifically, the curved surface transition is consistent with the curved surface transition form between the first tube seat and the main steam pipe.

[0059] The first pipeline 4 is provided with a radiation monitoring instrument, which can monitor the content of radioactive substances in the heat transfer medium in the water tank in real time, avoid leakage of radioactive substances in the reactor, and ensure the safety of the public.

[0060] A water tank leakage monitoring pipeline is provided between the heat exchange water tank 14 and the wall. Specifically, a water tank leakage monitoring pipeline is provided between the steel coating surface of the heat exchange water tank and the concrete wall, so as to monitor the integrity of the water tank in real time.

[0061] A maintenance platform is provided between the inner wall of the heat exchange tank 14 and the condenser 9. To facilitate maintenance, a steel ladder is provided in the heat exchange tank to climb to the steel platform between the heat exchange tank and the condenser. Because the space between the heat exchange tank and the condenser is very narrow, a maintenance platform is provided between the two.

[0062] Through the above-mentioned embodiments of the present invention, the present invention achieves the following beneficial effects:

[0063] 1. The first pipe seat designed is used for connecting the first pipeline with the seat of the main steam pipe of the steam generator, which can effectively prevent the connection from collapsing, deforming or cracking under the action of external force, thereby improving the working stability of the secondary side waste heat removal system of the passive steam generator.

[0064] 2. The designed U-shaped water seal reduces the impact of the heat transfer medium on the condenser heat exchange tube, prevents damage to the equipment, and improves system stability. The drain and exhaust ports designed in the U-shaped water seal, heat exchange water tank, and water supply tank ensure that water can be drained and exhausted in time when repairing the equipment.

[0065] 3. The designed water replenishment tank can replenish the heat transfer medium in time when the heat transfer medium on the secondary side of the evaporator is insufficient, ensuring the normal operation of the passive secondary side waste heat removal system and ultimately taking out the core heat. The water tank leakage monitoring pipeline is designed between the water exchange tank and the concrete wall to ensure real-time detection of the integrity of the water tank.

[0066] 4. The circulating purification pipelines designed in the condenser, water supply tank and heat exchange water tank ensure the cleanliness of the heat transfer medium in the system. The radiation detection instrument designed in the first pipeline ensures real-time monitoring of the radioactive substance content of the heat transfer medium in the water tank.

[0067] 5. The designed second pipe seat is used for connecting the second pipeline with the main water supply pipe of the steam generator, which can effectively prevent the connection from collapsing, deforming or cracking under the action of external force, thereby improving the working stability of the secondary side waste heat removal system of the passive steam generator.

[0068] 6. Anti-swing parts are designed to prevent pipeline rupture and swing against the steel lining of the containment. The maintenance platform designed outside the heat exchange water tank and condenser ensures convenient system maintenance.

[0069] The above are only a number of specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0070] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0071] It should be noted that, in the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

Claims

1. A passive steam generator secondary side waste heat removal system, characterized in that: The invention comprises a first tube seat (3), a first pipeline (4), a condenser (9) and a second pipeline (10); the condenser (9) is fluidically connected to the first pipeline (4) and the second pipeline (10); the first pipeline (4) is connected to a main steam pipeline (2) of a steam generator (1) through the first tube seat (3); the second pipeline (10) is connected to a main water supply pipeline (11) of the steam generator (1); the first tube seat (3) is a hollow structure; the first tube seat (3) comprises an inlet end and an outlet end; the outlet end is a side of the first tube seat (3) connected to the main steam pipeline (2) of the steam generator (1); the inlet end is a side of the first tube seat (3) connected to the first pipeline (4); the wall thickness of the first tube seat (3) near the inlet end is greater than the wall thickness near the outlet end; the connection between the first tube seat (3) and the main steam pipeline (2) is a curved surface transition.

2. The passive steam generator secondary side waste heat removal system according to claim 1, characterized in that: At least 85% of the length of the first tube seat (3) in the axial direction from the inlet end to the outlet end is a tubular inner cavity with a constant inner diameter, and at most 15% of the length of the first tube seat (3) in the axial direction from the outlet end to the inlet end has an inner diameter greater than the inner diameter of the tubular inner cavity.

3. The passive steam generator secondary side waste heat removal system according to claim 1, characterized in that: The first pipeline (4) comprises a U-shaped water seal (7), and the length from the U-shaped water seal (7) to the connection end of the first pipeline (4) and the condenser (9) accounts for at most 10% of the entire length of the first pipeline (4).

4. The passive steam generator secondary side waste heat removal system according to claim 3, characterized in that: The two ends of the U-shaped water seal (7) are local highest points, and the local highest points are inflection points near the end points of the U-shaped water seal. An exhaust port is provided at the local highest point, and a drain port (8) is provided at the bottom of the U-shaped water seal (7).

5. The passive steam generator secondary side waste heat removal system according to claim 4, characterized in that: The local highest point of the U-shaped water seal (7) in the first pipeline (4) is higher than the entire first pipeline (4), the first pipe seat (3) is lower than the entire first pipeline (4), and the connection end of the second pipeline (10) and the condenser (9) is higher than the entire second pipeline (10).

6. The passive steam generator secondary side waste heat removal system according to claim 1, characterized in that: When the passive secondary side waste heat removal system is in operation, in at least 90% of the length of the first pipeline (4), the heat transfer medium moves in a direction that overcomes gravity, and in at least 90% of the length of the second pipeline (10), the heat transfer medium does not move in a direction that overcomes gravity.

7. The passive steam generator secondary side waste heat removal system according to claim 1, characterized in that: It also comprises a water replenishment tank (13), the water inlet of the water replenishment tank (13) being fluidically connected to the first pipeline (4), and the water outlet being fluidically connected to the second pipeline (10), and the water replenishment tank (13) is also provided with an exhaust port and a drain port.

8. The passive steam generator secondary side waste heat removal system according to claim 1, characterized in that: It also includes a second pipe seat (11), which is fluidically connected to the main water supply pipe (12) of the steam generator (1) and one end of the second pipeline (10), respectively, and the second pipe seat (11) includes a tubular inner cavity with a constant inner diameter along the axial direction, and the connection between the second pipe seat (11) and the main water supply pipe (12) is a curved surface transition.

9. The passive steam generator secondary side waste heat removal system according to claim 1, characterized in that: It also comprises a heat exchange water tank (14), the heat exchange water tank (14) being higher than the steam generator (1) to form a height difference, the condenser (9) being arranged at the bottom of the heat exchange water tank (14), and the heat exchange water tank (14) being provided with an exhaust port.

10. The passive steam generator secondary side waste heat removal system according to claim 9, characterized in that: It also comprises a circulation purification pipeline, and the condenser (9) and the heat exchange water tank (14) are provided with the circulation purification pipeline.

11. The passive steam generator secondary side waste heat removal system according to claim 1, characterized in that: It also includes a penetration piece (6) which is a hollow structure. The first pipeline (4) and the second pipeline (10) pass through the containment shell through the penetration piece (6) and are fluidically connected to the main steam pipeline (2) and the main feedwater pipeline (12) respectively.

12. The passive steam generator secondary side waste heat removal system according to claim 1, characterized in that: It also includes an anti-swinging member (5), which includes a frame with inclined supports and is arranged near the place where the first pipeline (4) and / or the second pipeline (10) passes through the containment shell, and at least part of the anti-swinging member (5) is located between the containment shell and the first pipeline (4) and / or the second pipeline (10).

13. The passive steam generator secondary side waste heat removal system according to claim 1, characterized in that: The first pipeline (4) also includes a radiation monitoring instrument.

14. The passive steam generator secondary side waste heat removal system according to claim 9, characterized in that: It also includes a water tank leakage monitoring pipeline, which is arranged between the water exchange water tank (14) and the wall.

15. The passive steam generator secondary side waste heat removal system according to claim 9, characterized in that: Maintenance platforms are provided inside the water exchange tank (14) and outside the condenser (9).

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