Auxiliary water supply system of nuclear power unit

Abstract

The utility model discloses an auxiliary water supply system of a nuclear power unit, which comprises at least one water replenishing mechanism, and the water replenishing mechanism comprises a condenser, a main water replenishing pipeline, a bypass water replenishing pipeline and an auxiliary water supply system water storage tank. According to the auxiliary water supply system of the nuclear power unit, the bypass water replenishing pipeline is additionally arranged, meanwhile, the first manual isolating valve, the pneumatic isolating valve and the second manual isolating valve are arranged on the bypass water replenishing pipeline, so that automatic water replenishing control is achieved, and the implementation mode is simple and economical. According to the nuclear power unit auxiliary water supply system, through reasonable arrangement of the water supply pipeline and the water production pipeline, the required water supply flow is achieved, the water supply flow does not need to be manually adjusted in the water supply process, manpower is saved, meanwhile, the risk that the pressure of the water storage tank of the auxiliary water supply system is high is reduced, and the water supply efficiency is improved. The problems that daily water replenishing of the water storage tank of the auxiliary water supply system is long in time consumption and high in manpower consumption are solved, and the risk of human errors is reduced due to the fact that on-site online personnel are not needed.

Description

Technical Field

[0001] The utility model relates to the field of production and operation of nuclear power plants, in particular to an auxiliary water supply system for nuclear power units. Background Art

[0002] The auxiliary feedwater system (ASG) is one of the dedicated safety facilities of a pressurized water reactor nuclear power plant. The auxiliary feedwater system serves as a backup system for supplying feedwater to the secondary circuit side of the steam generator when the main feedwater supply is lost. The heat discharged from the primary circuit is supplied to the secondary circuit through the steam generator supplied by the auxiliary feedwater system (ASG), and the secondary circuit itself is cooled by steam discharge to the condenser or to the atmosphere.

[0003] During normal operation, the pneumatic pump lubrication of the auxiliary water supply system consumes 20m3 of 3 Water is needed, so the water tank needs to be replenished regularly. Since the water tank has requirements for the oxygen content of the replenished water, the replenishment and filling of the water tank are replenished by the degassing device or the condensate pump. When the unit is operating normally, the condenser vacuum is normal and the oxygen content of the condensed water is normal. A pipeline is led out from the outlet of the condensate pump to replenish the water tank.

[0004] The current problem is that the auxiliary water supply system water tank does not have an automatic water replenishment function. On-site personnel need to control the opening and closing of multiple valves. Because the valves are scattered and cover multiple unit valves, it takes a long time and is easy to go to the wrong interval, resulting in human-caused incidents. At the same time, during the water replenishment process, it is necessary to control the water replenishment flow by controlling the opening of the isolation valve. When the water replenishment flow is too large, the auxiliary water supply system water tank will cause a high pressure alarm. If the water replenishment flow is too small, it will take a long time to replenish water. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide an auxiliary water supply system for a nuclear power unit to solve the problem that the water storage tank of the auxiliary water supply system has no automatic water replenishment function, resulting in a long water replenishment time.

[0006] The technical solution adopted by the utility model to solve the technical problem is: constructing an auxiliary water supply system for a nuclear power unit, which includes at least one water supply mechanism, and the water supply mechanism includes a condenser, a main water supply pipeline, a bypass water supply pipeline and an auxiliary water supply system water storage tank;

[0007] The two ends of the main water supply pipeline are respectively connected to the condenser and the auxiliary water supply system water storage tank, and the main water supply pipeline is provided with a condensate pump assembly and a main control valve assembly in sequence along the liquid flow direction;

[0008] The inlet end of the bypass water supply pipeline is connected to the condensate pump assembly and the main control valve assembly, and the outlet end of the bypass water supply pipeline is connected between the main control valve assembly and the auxiliary water supply system water tank;

[0009] The bypass water supply pipeline is provided with a first manual isolation valve, a pneumatic isolation valve and a second manual isolation valve in sequence along the liquid flow direction.

[0010] In some embodiments, a liquid level measuring device is provided in the auxiliary water supply system water tank;

[0011] The condenser is provided with an air pressure measuring device;

[0012] The main water supply pipeline is provided with an oxygen concentration measuring device.

[0013] In some embodiments, the condensate pump assembly includes a plurality of condensate pumps, and the plurality of condensate pumps are arranged in parallel.

[0014] In some embodiments, the auxiliary water supply system of the nuclear power unit includes a heat exchanger, a first outlet end of the heat exchanger is connected to a water supply pipeline, and an interface end of the main water supply pipeline is connected to the water supply pipeline;

[0015] The water delivery pipeline is also connected to a softened water delivery pipeline, and the outlet end of the softened water delivery pipeline is connected to a softened water storage tank.

[0016] In some embodiments, the auxiliary water supply system of the nuclear power unit further includes a degassing tower, a first water supply pipeline, and a second water supply pipeline;

[0017] The two ends of the first water supply pipeline are respectively connected to the first outlet end of the degassing tower and the first inlet end of the heat exchanger, and the first water supply pipeline is provided with a first regulating valve, a first water supply pump, a second regulating valve and a multi-way valve in sequence along the liquid flow direction;

[0018] The two ends of the second water supply pipeline are respectively connected to the interface end of the first water supply pipeline and the second inlet end of the heat exchanger, and the second water supply pipeline is provided with a third regulating valve, a second water supply pump, a fourth regulating valve and a fifth regulating valve in sequence along the liquid flow direction;

[0019] The second water supply pipeline is also connected to the water delivery pipeline through a connecting pipeline.

[0020] In some embodiments, the second water supply pipeline is connected to a chemical reagent system, a conventional island desalted water distribution system, an auxiliary feed water storage tank, and a nuclear island desalted water distribution system;

[0021] The chemical reagent system is connected between the interface end of the first water supply pipeline and the third regulating valve;

[0022] The conventional island desalinated water distribution system is connected between the interface end of the first water supply line and the third regulating valve;

[0023] The auxiliary water supply tank is connected between the third regulating valve and the second water supply pump;

[0024] The nuclear island desalted water distribution system is connected between the fourth regulating valve and the fifth regulating valve.

[0025] In some embodiments, the auxiliary water supply system of the nuclear power unit further includes a return water pipeline, and two ends of the return water pipeline are respectively connected to the second outlet end of the heat exchanger and the first inlet end of the degassing tower;

[0026] The first water supply pipeline is also connected to the return water pipeline through a bypass pipeline, and the input end of the bypass pipeline is connected to the multi-way valve.

[0027] In some embodiments, the auxiliary water feed system of the nuclear power unit also includes a steam pipeline, the inlet end of the steam pipeline is connected to a gas storage and distribution system and an auxiliary steam distribution system, and the outlet end of the steam pipeline is connected to the steam inlet end of the degassing tower.

[0028] In some embodiments, the auxiliary water supply system of the nuclear power unit further includes a control tank and a cooling water tank;

[0029] The control box is connected to the second outlet end of the degassing tower, the cooling water tank is connected to the outlet end of the control box, and the outlet end of the cooling water tank is connected to a cooling water system.

[0030] In some embodiments, the auxiliary water supply system of the nuclear power unit further comprises an exhaust pipeline, the inlet end of the exhaust pipeline is connected to the third outlet end of the degassing tower, and the outlet end of the exhaust pipeline is connected to the atmosphere;

[0031] The control box is connected to the exhaust steam line through a steam outlet line.

[0032] The implementation of the utility model has the following beneficial effects: the auxiliary water supply system of the nuclear power unit realizes automatic water supply control by adding a bypass water supply pipeline, and at the same time, a first manual isolation valve, a pneumatic isolation valve and a second manual isolation valve are arranged on the bypass water supply pipeline, and the implementation method is simple and economical. The auxiliary water supply system of the nuclear power unit realizes the required water supply flow rate through reasonable water supply pipeline and water production pipeline settings. During the water supply process, there is no need to manually adjust the water supply flow rate, which saves manpower and reduces the risk of high pressure in the water storage tank of the auxiliary water supply system. It solves the problem of long time and high manpower consumption in daily water supply of the water storage tank of the auxiliary water supply system. Since no personnel are required to be online on site, the risk of human error is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solution of the utility model, the utility model will be further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the following drawings only show certain embodiments of the utility model, and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0034] Figure 1 It is a schematic diagram of the overall structure of the auxiliary water supply system of a nuclear power unit in some embodiments of the utility model;

[0035] Figure 2 It is a structural schematic diagram of the water replenishment mechanism in some embodiments of the utility model. DETAILED DESCRIPTION

[0036] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "up", "down", "left", "right", "longitudinal", "horizontal", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings, are constructed and operated in a specific direction, and are only for the convenience of describing the present technical solution, rather than indicating that the device or element referred to must have a specific direction, and therefore cannot be understood as a limitation to the present invention.

[0037] It should also be noted that, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed", "set" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may be one or more intermediate elements. The terms "first", "second", "third", etc. are only for the convenience of describing the present technical solution, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", "third", etc. can explicitly or implicitly include one or more of the features. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to the specific circumstances.

[0038] See also Figure 1 and Figure 2The utility model discloses an auxiliary water supply system for a nuclear power unit, which includes at least one water supply mechanism 1. The water supply mechanism 1 may include a condenser 11, a main water supply pipeline 12, a bypass water supply pipeline 13 and an auxiliary water supply system water tank 14. The two ends of the main water supply pipeline 12 are respectively connected to the condenser 11 and the auxiliary water supply system water tank 14. A condensate pump assembly 15 and a main control valve assembly 16 are sequentially arranged on the main water supply pipeline 12 along the liquid flow direction. The inlet end of the bypass water supply pipeline 13 is connected between the condensate pump assembly 15 and the main control valve assembly 16, and the outlet end of the bypass water supply pipeline 13 is connected between the main control valve assembly 16 and the auxiliary water supply system water tank 14. A first manual isolation valve 131, a pneumatic isolation valve 132 and a second manual isolation valve 133 are sequentially arranged on the bypass water supply pipeline 13 along the liquid flow direction.

[0039] Specifically, the condenser 11 is a type of heat exchanger that can convert gas or vapor into liquid and transfer the heat in the pipe to the air near the pipe in a very fast manner. The condenser 11 can provide water replenishment for the auxiliary water supply system water tank 14. The condenser 11 can transport water to the auxiliary water supply system water tank 14 through the main water replenishment pipeline 12 and the bypass water replenishment pipeline 13.

[0040] In addition, the number of the water replenishment mechanism 1 can be one or more, and in this embodiment, the main control valve assembly 16 includes five main control valves. In some other embodiments, the number of the main control valves can be set according to actual conditions, and no specific limitation is made here. The main control valve can control the water replenishment flow rate of the main water replenishment pipeline 12.

[0041] Understandably, since the current auxiliary water supply system water tank 14 does not have an automatic water replenishment function, on-site personnel need to control the opening and closing of multiple valves. Due to the dispersed valve positions and the large valve covering the unit, it takes a long time to replenish water, and the staff is prone to go to the wrong interval, resulting in human-caused incidents. At the same time, during the water replenishment process, it is necessary to control the water replenishment flow rate by controlling the opening of the isolation valve. When the water replenishment flow rate is too large, it will cause a high pressure alarm in the auxiliary water supply system water tank 14. If the water replenishment flow rate is too small, it will take a long time to replenish water. Therefore, in this utility model, by adding a bypass water replenishment pipeline 13 to the auxiliary water supply system water tank 14, and setting the bypass water replenishment pipeline 13 and the isolation valve on the bypass water replenishment pipeline 13, the automatic water replenishment function of the auxiliary water supply system water tank 14 is realized.

[0042] At the same time, a liquid level measuring device 141 is provided in the auxiliary water supply system water tank 14, and the liquid level measuring device 141 can measure the water level in the auxiliary water supply system water tank 14; an air pressure measuring device 111 is provided in the condenser 11, and the air pressure measuring device 111 can measure the air pressure of the condenser 11; an oxygen concentration measuring device 121 is provided on the main water supply pipeline 12, and the oxygen concentration measuring device 121 can measure the oxygen concentration on the main water supply pipeline 12.

[0043] In addition, the condensate pump assembly 15 includes multiple condensate pumps, which are arranged in parallel to ensure that when one condensate pump fails to shut down, another condensate pump can be used to replenish the auxiliary water supply system water tank 14. In this embodiment, the number of the condensate pumps is three.

[0044] In a specific embodiment, the main water supply pipeline 12 takes into account the outlet pressure of the condensate pump and limits the water supply flow rate to 10m when the valve is fully open. 3 / h, and in order to ensure that the water quality of the replenishment water meets the requirements, the conditions for the opening of the pneumatic isolation valve 132 are: the air pressure of the condenser 11 measured by the air pressure measuring device 111 is less than 10KPa, the oxygen concentration measuring device 121 measures the oxygen content is less than 100ppb, at least one condensate pump of the condensate pump assembly 15 is in operation, and the liquid level measuring device 141 measures the water level in the auxiliary water supply system water tank 14 to be between 13 meters and 14 meters. If the water level exceeds 14 meters, the pneumatic isolation valve 132 is closed. In addition, the first manual isolation valve 131 and the second manual isolation valve 133 are respectively installed on both sides of the pneumatic isolation valve 132. Under the condition that the condenser 11 does not have the ability to replenish water to the auxiliary water supply system water tank 14, the first manual isolation valve 131 and the second manual isolation valve 133 can be closed to ensure that the water source provided by the condenser 11 cannot pass through the bypass water supply pipeline 13. When the pneumatic isolation valve 132 is under fault inspection and repair, the first manual isolation valve 131 and the second manual isolation valve 133 may also be closed to ensure the safety of the pneumatic isolation valve 132 during the fault inspection and repair.

[0045] Further, the auxiliary water supply system of the nuclear power unit includes a heat exchanger 2, a water delivery pipeline 21 is connected to the first outlet end of the heat exchanger 2, the interface end of the main water supply pipeline 12 is connected to the water delivery pipeline 21, a softened water delivery pipeline 22 is also connected to the water delivery pipeline 21, and the outlet end of the softened water delivery pipeline 22 is connected to a softened water storage tank 23. It can be understood that the heat exchanger 2 is used for heat exchange of desalted water, and the heat exchanger 2 is preferably a regenerative heat exchanger 2. The desalted water treated by the heat exchanger 2 can enter the softened water storage tank 23 or the auxiliary water supply system storage tank 14 through the water delivery pipeline 21 according to the actual application conditions.

[0046] The auxiliary water supply system of the nuclear power unit also includes a degassing tower 31, a first water supply pipeline 32, and a second water supply pipeline 33. The two ends of the first water supply pipeline 32 are respectively connected to the first outlet end of the degassing tower 31 and the first inlet end of the heat exchanger 2. The first water supply pipeline 32 is provided with a first regulating valve 321, a first water supply pump 322, a second regulating valve 323 and a multi-way valve 324 in sequence along the liquid flow direction. The degassing tower 31 can be used to treat the system desalted water with a pH of 9, and the desalted water after degassing can be used by other components of the auxiliary water supply system of the nuclear power unit.

[0047] In a specific application, a pressure controller acting on the heating steam flow maintains the absolute pressure of the degassing tower 31 at 0.12 MPa, and the discharge rate of non-condensable substances is stabilized at 60 kg / h through an orifice plate on the exhaust pipeline. The degassing tower 31 uses Dalton's partial pressure law and Henry's law for thermal deoxygenation. The regulating valves mentioned above can be used to control the opening and closing of the liquid flow in each pipeline, and the water supply pump provides power for the flow of the liquid.

[0048] Further, the two ends of the second water supply pipeline 33 are respectively connected to the interface end of the first water supply pipeline 32 and the second inlet end of the heat exchanger 2, and the second water supply pipeline 33 is provided with a third regulating valve 331, a second water supply pump 332, a fourth regulating valve 333 and a fifth regulating valve 334 in sequence along the liquid flow direction. The second water supply pipeline 33 is connected with a chemical reagent system 41, a conventional island desalted water distribution system 42, an auxiliary feed water storage tank 43 and a nuclear island desalted water distribution system 44, the chemical reagent system 41 is connected between the interface end of the first water supply pipeline 32 and the third regulating valve 331, the conventional island desalted water distribution system 42 is connected between the interface end of the first water supply pipeline 32 and the third regulating valve 331, the auxiliary feed water storage tank 43 is connected between the third regulating valve 331 and the second water supply pump 332, and the nuclear island desalted water distribution system 44 is connected between the fourth regulating valve 333 and the fifth regulating valve 334. It can be understood that the chemical reagent system 41 can be used to chemically purify the desalted water flowing in the second water supply pipeline 33, while the conventional island desalted water distribution system 42, the auxiliary feed water storage tank 43 and the nuclear island desalted water distribution system 44 can provide desalted water replenishment for the auxiliary feed water system of the entire nuclear power unit.

[0049] In addition, the second water supply pipeline 33 is also connected to the water delivery pipeline 21 through a connecting pipeline 34, so that the desalted water on the second water supply pipeline 33 or the deoxygenated water treated by the degassing tower 31 can directly enter the water delivery pipeline 21. The connecting pipeline 34 is provided with corresponding control valves and filters, and the opening and closing of the control valve can be set according to the actual situation of the auxiliary water supply system of the entire nuclear power unit.

[0050] The auxiliary water supply system of the nuclear power unit further includes a return water pipeline 51, the two ends of which are respectively connected to the second outlet end of the heat exchanger 2 and the first inlet end of the degassing tower 31, and the first inlet end of the degassing tower 31 is located at the top of the degassing tower 31. In general, the deionized water to be deoxygenated enters the heat exchanger 2 through the second water supply pipeline 33 at a temperature of 5°C to 40°C, and the high-temperature deoxygenated water discharged from the degassing tower 31 enters the heat exchanger 2 through the first water supply pipeline 32. The temperature of the high-temperature deoxygenated water when discharged from the degassing tower 31 is 105°C. The deionized water to be deoxygenated is heated by the high-temperature deoxygenated water in the heat exchanger 2. The deionized water to be deoxygenated leaves the heat exchanger 2 at a temperature between 88.5°C and 96°C. The deionized water to be deoxygenated is sent to the top of the degassing tower 31 through the return water pipeline 51, and is atomized at the top of the degassing tower 31, and then degassing is performed. In addition, the high-temperature deoxygenated water originally discharged from the degassing tower 31 is also cooled to the required temperature in the heat exchanger, and its water temperature is below 50° C., and then transported to the corresponding water tank through the water pipeline 21.

[0051] The first water supply pipeline 32 is also connected to the return pipeline 51 through a bypass pipeline 52. The input end of the bypass pipeline 52 is connected to the multi-way valve 324. The high-temperature deoxygenated water discharged from the degassing tower 31 on the first water supply pipeline 32 can flow directly back to the return pipeline 51 through the return pipeline 51, and can enter the degassing tower 31 for treatment together with the desalted water to be deoxygenated after being treated by the heat exchanger.

[0052] Furthermore, the auxiliary water supply system of the nuclear power unit also includes a steam pipeline 53, the inlet end of the steam pipeline 53 is connected to the gas storage and distribution system 45 and the auxiliary steam distribution system 46, and the outlet end of the steam pipeline 53 is connected to the steam inlet end of the degassing tower 31. The gas storage and distribution system 45 and the auxiliary steam distribution system 46 can provide auxiliary steam to the degassing tower 31, and the heat required for the degassing tower 31 to heat the water to be deoxygenated is supplied by the auxiliary steam.

[0053] The auxiliary water supply system of the nuclear power unit also includes a control box 54 and a cooling water tank 55. The control box 54 is connected to the second outlet end of the degassing tower 31, and the cooling water tank 55 is connected to the outlet end of the control box 54. The outlet end of the cooling water tank 55 is connected to the cooling water system 47. It can be understood that since the auxiliary steam heats the water to be deoxygenated in the degassing tower, the auxiliary steam condenses into water in the lower tube bundle of the degassing tower 31 after heating, and the auxiliary steam condensed water is collected in the control box 54 and cooled by the cooling water tank 55 connected thereto. The cooled water can be discharged to the auxiliary steam production system for reuse.

[0054] The auxiliary water supply system of the nuclear power unit further includes an exhaust steam pipeline 56, the inlet end of the exhaust steam pipeline 56 is connected to the third outlet end of the degassing tower 31, the outlet end of the exhaust steam pipeline 56 is connected to the atmosphere, and the control box 54 is connected to the exhaust steam pipeline 56 through the steam outlet pipeline 57. The exhaust steam pipeline 56 and the steam outlet pipeline 57 are both provided with corresponding emission control valves and filters, and the filtered gas can be discharged into the atmosphere through the exhaust steam pipeline 56 and the steam outlet pipeline 57.

[0055] In summary, the auxiliary water supply system of the nuclear power unit realizes automatic water supply control by adding a bypass water supply pipeline 13, and at the same time, the bypass water supply pipeline 13 is provided with a first manual isolation valve 131, a pneumatic isolation valve 132 and a second manual isolation valve 133, and the implementation method is simple and economical. The auxiliary water supply system of the nuclear power unit as a whole realizes the required water supply flow rate through the reasonable setting of water supply pipelines and water production pipelines. During the water supply process, there is no need to manually adjust the water supply flow rate, which saves manpower and reduces the risk of high pressure in the auxiliary water supply system water tank 14. It solves the problem that the daily water supply of the auxiliary water supply system water tank 14 is time-consuming and labor-intensive. Since no personnel are required to be online on site, the risk of human error is reduced.

[0056] It can be understood that the above embodiments only express the preferred implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the utility model. It should be pointed out that, for ordinary technicians in this field, without departing from the concept of the utility model, the above-mentioned technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the utility model. Therefore, all equivalent changes and modifications made to the scope of the claims of the utility model should fall within the scope of the claims of the utility model.

Claims

1. A nuclear power unit auxiliary water supply system, characterized in that: The invention comprises at least one water replenishment mechanism (1), wherein the water replenishment mechanism (1) comprises a condenser (11), a main water replenishment pipeline (12), a bypass water replenishment pipeline (13) and an auxiliary water supply system water storage tank (14); The two ends of the main water supply pipeline (12) are respectively connected to the condenser (11) and the auxiliary water supply system water storage tank (14); a condensate pump assembly (15) and a main control valve assembly (16) are sequentially arranged on the main water supply pipeline (12) along the liquid flow direction; The inlet end of the bypass water supply pipeline (13) is connected between the condensate pump assembly (15) and the main control valve assembly (16), and the outlet end of the bypass water supply pipeline (13) is connected between the main control valve assembly (16) and the auxiliary water supply system water storage tank (14); The bypass water supply pipeline (13) is provided with a first manual isolation valve (131), a pneumatic isolation valve (132) and a second manual isolation valve (133) in sequence along the liquid flow direction.

2. The auxiliary water supply system for a nuclear power plant according to claim 1, characterized in that: The auxiliary water supply system water storage tank (14) is provided with a liquid level measuring device (141); The condenser (11) is provided with an air pressure measuring device (111); The main water replenishment pipeline (12) is provided with an oxygen concentration measuring device (121).

3. The auxiliary water supply system for a nuclear power plant according to claim 1, characterized in that: The condensate pump assembly (15) comprises a plurality of condensate pumps, and the plurality of condensate pumps are arranged in parallel.

4. The auxiliary water supply system for a nuclear power plant according to claim 1, characterized in that: The auxiliary water supply system of the nuclear power unit comprises a heat exchanger (2), a first outlet end of the heat exchanger (2) is connected to a water supply pipeline (21), and an interface end of the main water supply pipeline (12) is connected to the water supply pipeline (21); The water delivery pipeline (21) is also connected to a softened water delivery pipeline (22), and the outlet end of the softened water delivery pipeline (22) is connected to a softened water storage tank (23).

5. The auxiliary water supply system for a nuclear power plant according to claim 4, characterized in that: The auxiliary water supply system of the nuclear power unit further includes a degassing tower (31), a first water supply pipeline (32), and a second water supply pipeline (33); The two ends of the first water supply pipeline (32) are respectively connected to the first outlet end of the degassing tower (31) and the first inlet end of the heat exchanger (2); the first water supply pipeline (32) is provided with a first regulating valve (321), a first water supply pump (322), a second regulating valve (323) and a multi-way valve (324) in sequence along the liquid flow direction; The two ends of the second water supply pipeline (33) are respectively connected to the interface end of the first water supply pipeline (32) and the second inlet end of the heat exchanger (2); the second water supply pipeline (33) is provided with a third regulating valve (331), a second water supply pump (332), a fourth regulating valve (333) and a fifth regulating valve (334) in sequence along the liquid flow direction; The second water supply pipeline (33) is also connected to the water delivery pipeline (21) via a connecting pipeline (34).

6. The auxiliary water supply system for a nuclear power plant according to claim 5, characterized in that: The second water supply pipeline (33) is connected to a chemical reagent system (41), a conventional island desalted water distribution system (42), an auxiliary feed water storage tank (43) and a nuclear island desalted water distribution system (44); The chemical reagent system (41) is connected between the interface end of the first water supply pipeline (32) and the third regulating valve (331); The conventional island desalinated water distribution system (42) is connected between the interface end of the first water supply pipeline (32) and the third regulating valve (331); The auxiliary water supply storage tank (43) is connected between the third regulating valve (331) and the second water supply pump (332); The nuclear island desalted water distribution system (44) is connected between the fourth regulating valve (333) and the fifth regulating valve (334).

7. The auxiliary water supply system for a nuclear power plant according to claim 5, characterized in that: The auxiliary water supply system of the nuclear power unit further comprises a return water pipeline (51), and two ends of the return water pipeline (51) are respectively connected to the second outlet end of the heat exchanger (2) and the first inlet end of the degassing tower (31); The first water supply pipeline (32) is also connected to the return water pipeline (51) via a bypass pipeline (52), and the input end of the bypass pipeline (52) is connected to the multi-way valve (324).

8. The auxiliary water supply system for a nuclear power plant according to claim 5, characterized in that: The auxiliary water supply system of the nuclear power unit also includes a steam pipeline (53), the inlet end of the steam pipeline (53) is connected to the gas storage and distribution system (45) and the auxiliary steam distribution system (46), and the outlet end of the steam pipeline (53) is connected to the steam inlet end of the degassing tower (31).

9. The auxiliary water supply system for a nuclear power plant according to claim 5, characterized in that: The auxiliary water supply system of the nuclear power unit also includes a control box (54) and a cooling water tank (55); The control box (54) is connected to the second outlet end of the degassing tower (31), the cooling water tank (55) is connected to the outlet end of the control box (54), and the outlet end of the cooling water tank (55) is connected to a cooling water system (47).

10. The auxiliary water supply system for a nuclear power plant according to claim 9, characterized in that: The auxiliary water supply system of the nuclear power unit further comprises a steam exhaust pipeline (56), the inlet end of the steam exhaust pipeline (56) is connected to the third outlet end of the degassing tower (31), and the outlet end of the steam exhaust pipeline (56) is connected to the atmosphere; The control box (54) is connected to the steam exhaust pipeline (56) via a steam outlet pipeline (57).

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