Water system and cooling method for nuclear power plant

Abstract

The application discloses a nuclear power plant water system and a cooling method. The nuclear power plant water system comprises a plurality of series and non-safety level water pools. Each series is provided with one safety level water pool, and each safety level water pool is communicated with each other. Each series has a first working condition and a second working condition. The sum of the water quantity carried by any two safety level water pools can at least supply the system to run for 3 days in the second working condition. The non-safety level water pool can at least store the water quantity for the system to run for 27 days in the second working condition. The water resources stored in the non-safety level water pool and the safety level water pool can be flexibly allocated to different series according to actual needs, so that the idle and waste of water resources are avoided, the demand of the overall water storage quantity is effectively reduced, and the construction and maintenance costs of the water pool are reduced. The reduction of the overall water storage quantity of the nuclear power plant means that the occupation and consumption of land and water resources in the construction process of the water pool are reduced.

Description

Technical Field

[0001] The present invention relates to the field of nuclear power technology, and in particular to a water system and cooling method for a nuclear power plant. Background Art

[0002] HAD102 / 08-2020 (full name: "Design of Reactor Coolant Systems and Related Systems of Nuclear Power Plants") requires that when the capacity requirements of the final heat sink in the short and long term stages do not allow for the use of inexhaustible natural water bodies, "the capacity of the final heat sink should be guaranteed by the water available at any time on the site", and "the water available at any time... is generally 30 days"; "... after any hypothetical initiating event (external emergencies such as earthquakes), the minimum amount of water required to bring the reactor to a safe shutdown state (including a margin for uncertainty) should be immediately available", and the minimum amount of water required "is designed to ensure 3 days of heat extraction" and "... should have been stored in the corresponding final heat sink system (such as a water tank, cooling tower pool)".

[0003] Because the final heat sink system is typically composed of several mutually redundant trains, the design typically employs a 30-day water storage tank for each train, with these tanks isolated from each other. In other words, in traditional designs, the total system water tank volume is equal to the number of trains multiplied by the 30-day water volume required for a single train failure. While this design approach meets regulatory requirements, it significantly increases project costs. Summary of the Invention

[0004] The main purpose of the present invention is to propose a water system and cooling method for a nuclear power plant, aiming to solve the technical problem of how to reduce the cost of the water system of a nuclear power plant while ensuring that the nuclear power plant has sufficient water.

[0005] To achieve the above objectives, the present invention proposes a water system for a nuclear power plant, comprising:

[0006] Multiple series, each series is equipped with a safety-level water tank, each of the safety-level water tanks is connected to each other, each series has a first operating condition and a second operating condition, and the total water volume carried by any two of the safety-level water tanks is configured to be able to supply the system with at least 3 days of operation under the second operating condition;

[0007] The non-safety-level water tank is configured to store at least enough water for the system to operate for 27 days under the second working condition. After the safety-level water tank has operated for 3 days under the second working condition, the non-safety-level water tank is connected to each of the safety-level water tanks.

[0008] Specifically, the total volume of the safety class water pool and the non-safety class water pool of the water system of the nuclear power plant provided by the present application is the water volume required for the entire system to operate for 30 days under accident conditions (at least two safety class water pools provide 3 days of water consumption, and the non-safety class water pool provides 27 days of water consumption). It should be noted that the water volume required for the entire system to operate for 30 days under accident conditions is greater than the water volume required for a single series to operate for 30 days under accident conditions, but compared with the related art in which each series is separately provided with the water volume required for the series to operate for 30 days under accident conditions, the water volume of the water system of the nuclear power plant of the present application is much smaller than the total volume of the system in the conventional design (the total volume in the conventional design = the number of series multiplied by the water volume required for a single series to operate for 30 days under accident conditions), and in the water system of the nuclear power plant of the present application, the volume of the safety class water pool of each series is smaller, and the volume of each safety class water pool is greatly reduced, thereby reducing the engineering construction and maintenance costs of the safety class water pool, and reducing the occupation and consumption of land and water resources by the system.

[0009] In some embodiments, each of the series includes a cooling tower, a water pump, and a heat exchanger, the water pump is configured to be capable of communicating with the safety class water pool and capable of guiding the cooling water in the safety class water pool to the heat exchanger, the heat exchanger is configured to be capable of transferring the high-temperature heat generated by the nuclear reactor to the cooling water, and the cooling water enters the cooling tower after passing through the heat exchanger to release heat and flows into the safety class water pool again.

[0010] In some embodiments, each of the series further includes a first filter and a second filter, the first filter is arranged between the safety class water pool and the water pump, and the second filter is arranged between the water pump and the heat exchanger.

[0011] In some embodiments, the water system of the nuclear power plant further includes a sewage device, the sewage device is configured to be capable of discharging sewage generated by the first filter;

[0012] and / or,

[0013] the sewage device is configured to be capable of discharging sewage generated by the second filter;

[0014] and / or,

[0015] the sewage device is configured to be capable of discharging sewage generated by the cooling tower.

[0016] In some embodiments, the heat exchanger of each of the series is configured to be capable of communicating with the safety class water pool of any other series.

[0017] In some embodiments, the nuclear power plant water system also includes a first connecting pipe and multiple first isolation valves. Each of the safety-level water pools is connected through the first connecting pipe. The first isolation valve is arranged on the first connecting pipe and is configured to connect or isolate two connected safety-level water pools.

[0018] In some embodiments, two first isolation valves are provided between the two connected safety-level water pools, namely the first valve and the second valve. The two connected safety-level water pools are respectively the first water pool and the second water pool. The non-safety-level water pool is connected to the first connecting pipe between the first water pool and the second water pool. The first valve is configured to connect or disconnect the first water pool and the non-safety-level water pool, and the second valve is configured to connect or disconnect the second water pool and the non-safety-level water pool.

[0019] In some embodiments, the nuclear power plant water system further includes a plurality of second connecting pipes, each of the safety-level water pools is connected to at least one second connecting pipe, and each of the second connecting pipes is connected to the non-safety-level water pool.

[0020] In some embodiments, the nuclear power plant water system also includes a second isolation valve, which is arranged between the non-safety-level water pool and the safety-level water pool to control the connection or isolation between the safety-level water pool and the non-safety-level water pool.

[0021] In some embodiments, the nuclear power plant water system further includes a water replenishment device, which is configured to replenish cooling water for the safety-level water pool operating under the first operating condition.

[0022] In some embodiments, the nuclear power plant water system further comprises a water supply pump, the water supply pump being disposed between the non-safety-grade water pool and the safety-grade water pool, and the water supply pump being configured to direct cooling water from the non-safety-grade water pool to the safety-grade water pool;

[0023] and / or

[0024] The water replenishment pump is arranged between the connected safety-level water pools.

[0025] In some embodiments, the nuclear power plant water system further includes a drug dosing device configured to deliver drugs into the safety-grade water pool.

[0026] A second aspect of the present invention further provides a cooling method applicable to the water system of a nuclear power plant described in any of the above embodiments, the cooling method comprising:

[0027] When any one of the series enters the second working condition, the safety-level water pool in the series becomes an emergency water pool, and at least one other safety-level water pool connected to the emergency water pool is controlled to replenish water to the emergency water pool;

[0028] After the accident water pool has been operating for 3 days, the non-safety-level water pool is controlled to replenish water to the accident water pool.

[0029] In some embodiments, when controlling the non-safety-level water pool to replenish water to the accident water pool, the non-safety-level water pool replenishes water to a second connecting pipe connecting the non-safety-level water pool and the accident water pool;

[0030] Alternatively, the non-safety-grade water pool supplies water to a first connecting pipe connecting the two safety-grade water pools.

[0031] In some embodiments, each of the series includes a cooling tower, a water pump, and a heat exchanger, wherein the heat exchanger is disposed between the water pump and the cooling tower, and the water pump is connected to the safety-level water pool, wherein the heat exchanger connected to the emergency water pool is a first heat exchanger, and the cooling method further includes:

[0032] After any one of the series enters the second operating condition and the emergency water pool is unable to supply water to the first heat exchanger, the safety-level water pool in at least one other series is controlled to supply water to the first heat exchanger.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] In the technical solution of the present invention, the water supply system of a nuclear power plant includes multiple series and non-safety-level water pools, wherein each series is equipped with a safety-level water pool, and each safety-level water pool is connected to each other in pairs, and the system has a first operating condition and a second operating condition. The total amount of water carried by any two safety-level water pools can supply the system with at least three days of operation under the second operating condition. Therefore, when a safety-level water pool fails, the safety-level water pools of other series can support the operation of the series with the failed safety-level water pool, reducing the impact on the cooling capacity of the entire nuclear power plant. In addition, when a series is in the second operating condition, the design of each safety-level water pool being connected to each other in pairs allows the water source of the other safety-level water pools to be allocated to the series in the second operating condition to ensure the rapid supply of cooling water, enhance the flexibility and adaptability of the system, and ensure that the cooling work of the entire nuclear power plant can be carried out continuously to ensure the safety of the nuclear power plant. The total water volume of any two safety-level water tanks is configured to be able to supply the system with water for at least three days of operation under the second operating condition. In an emergency, the system can maintain sufficient cooling capacity to cope with short-term failures or power outages. This ensures sufficient cooling water while reducing the construction and maintenance costs of the safety-level water tanks and saving water resources, effectively reducing safety hazards.

[0035] Furthermore, the non-safety-grade water tanks in this application can store at least 27 days of water to sustain the system's operation under the second operating condition. Compared to related art designs that require each series to have a 30-day water storage capacity to meet regulatory requirements, this effectively reduces the overall water storage requirement, thereby lowering the construction and maintenance costs of the tanks. Furthermore, since not all series are in the second operating condition simultaneously during nuclear power plant operation, the water stored in the non-safety-grade and safety-grade water tanks can be flexibly allocated to different series based on actual needs, avoiding idle and wasted water resources. This reduction in the overall water storage capacity of the nuclear power plant means less land and water resources are occupied and consumed during tank construction. This helps reduce the impact of nuclear power plant construction on the surrounding environment and enhances the feasibility of environmental protection and sustainable development. It should be noted that while the total water storage capacity of this application's design is lower than that of the traditional system, the 27-day water storage capacity of the non-safety-grade water tanks combined with the 3-day water storage capacity of the safety-grade water tanks still meets regulatory requirements for safe nuclear power plant operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0037] Figure 1 This is a schematic structural diagram of a water system for a nuclear power plant according to an embodiment of the present invention;

[0038] Figure 2 Schematic diagram of a cooling method according to an embodiment of the present invention;

[0039] Figure 3 Schematic diagram of a cooling method according to another embodiment of the present invention.

[0040] Description of Figure Numbers:

[0041] Nuclear power plant water system 100;

[0042] Series 110; safety-grade water pool 111; cooling tower 112; water pump 113; heat exchanger 114; first filter 115; second filter 116;

[0043] non-safety-grade pools 120;

[0044] First isolation valve 130;

[0045] a second isolation valve 140;

[0046] The water replenishing pump 150;

[0047] The first connecting pipe 160;

[0048] The second connecting pipe 170.

[0049] The purposes, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0051] In the related art, sea water is usually used to cool the equipment of a nuclear power plant. However, the cooling tower will cause water droplets to be blown away during the heat exchange process of the sea water carrying heat, so that the salt in the sea water adheres to each device, thereby causing the structure of each device to be corroded and even causing environmental problems. Therefore, in some mature designs, desalinated water is used as a working medium. However, the cooling system of a nuclear power plant requires a large amount of water resources, especially for nuclear power plants built in inland areas. The process of sea water desalination requires a large amount of energy consumption, and a large amount of desalinated water consumption will seriously increase the operating cost of the nuclear power plant (for nuclear power plants built in inland areas, it requires a great transportation cost to introduce desalinated water into the nuclear power plant built in the inland area). If fresh water is directly used to cool the nuclear power plant built in the inland area, because the cooling system of the nuclear power plant consumes a large amount of fresh water, it will cause the cooling water source of the nuclear power plant to be insufficient, thereby increasing the safety hazard of the nuclear power plant. In addition, in the related art, the cooling system design for the nuclear power plant usually sets a water pool with a water storage capacity of at least 30 days for each series to run in a high load state, which results in a very large amount of water consumption of the entire system. Fresh water resources are already scarce, and the use of the cooling system in the related art will seriously cause the cooling water source to be insufficient, which will cause the system to have a very high safety hazard. In addition, in the related art, each series is equipped with a water pool with a water storage capacity of at least 30 days, which will seriously increase the construction and maintenance cost of the water pool, and also occupy a large amount of land resources.

[0052] In view of this, please refer to Figure 1The present invention provides a nuclear power plant water system 100, comprising multiple series 110 and non-safety-rated water tanks 120. Each series 110 is equipped with a safety-rated water tank 111, and each safety-rated water tank 111 is interconnected. Each series 110 has a first operating condition and a second operating condition. In some embodiments, the cooling water source for series 110 in the first operating condition can be provided by the safety-rated water tank 111 or another external water source. The cooling water source for series 110 in the second operating condition can also be provided by the safety-rated water tank 111. It should be noted that in some embodiments, the series 110 in the first operating condition can be in normal operation, while the series 110 in the second operating condition can be in an abnormal operating condition (including earthquakes and loss of external power). For ease of understanding, the following description uses the system operating at high load as the second operating condition. The water consumption of the series 110 in the first operating condition is replenished by an external water replenishment system. The total water volume held by any two safety-rated water tanks 111 is configured to be sufficient to supply at least three days of system operation in the second operating condition.

[0053] Specifically, each series 110 is equipped with a safety-grade water tank 111. These safety-grade water tanks 111 are interconnected via pipes, forming a redundant water supply network. To ensure sufficient cooling water supply under the second operating condition, the total water volume of any two safety-grade water tanks 111 is sufficient to supply the system with water for at least three days of operation under the second operating condition. This ensures that in emergencies, the system has sufficient cooling water to maintain adequate cooling capacity to cope with short-term failures or power outages, mitigate safety hazards, and thus ensure the safe operation of the nuclear power plant. Furthermore, the nuclear power plant water system 100 also includes a non-safety-grade water tank 120. The non-safety-grade water tank 120 is configured to store water sufficient to supply the system with water for at least 27 days of operation under the second operating condition. After the safety-grade water tank 111 has operated under the second operating condition for three days, the non-safety-grade water tank 120 can be connected to each safety-grade water tank 111 via pipes to provide additional cooling water to each series 110. This ensures that the system can continuously provide sufficient cooling water during prolonged high-load operation, thus ensuring the normal operation of the nuclear power plant. Compared to related technologies that require each series to store 30 days of water to meet regulatory requirements, this effectively reduces the overall water storage requirement, thereby reducing the number of water tanks built and maintenance costs. It should be noted that reducing the overall water storage capacity of a nuclear power plant means reducing the land and water resource occupation and consumption during the construction of water tanks, which helps protect the ecological environment. In other words, the solution of this application not only meets nuclear power safety regulations, but also optimizes water resource utilization and reduces project costs.

[0054] Each series 110 is equipped with a safety-level water pool 111, and the safety-level water pools 111 are connected to each other in pairs. This allows the safety-level water pools 111 of other series 110 to provide a backup water source when a problem occurs with a safety-level water pool 111 of a series 110, thereby improving the redundancy and safety of the system. For example, when a safety-level water pool 111 fails or has insufficient water, the safety-level water pools 111 of other series 110 can support the operation of the faulty series 110, reducing the impact on the cooling capacity of the entire nuclear power plant. When a series 110 is in the second operating condition, the design of the safety-level water pools 111 being connected to each other in pairs allows the water sources of the other safety-level water pools 111 to be allocated to the series 110 in the second operating condition, thereby ensuring a rapid supply of cooling water and enhancing the flexibility and adaptability of the system.

[0055] See also Figure 1 In some embodiments, each series 110 includes a cooling tower 112, a water pump 113, and a heat exchanger 114. The water pump 113 is configured to connect to the safety-grade water pool 111 and direct the cooling water in the safety-grade water pool 111 to the heat exchanger 114. The heat exchanger 114 is configured to transfer the high-temperature heat generated by the nuclear reactor to the cooling water. After passing through the heat exchanger 114, the cooling water enters the cooling tower 112, releases heat, and then flows back into the safety-grade water pool 111. Specifically, the cooling process of each series 110 is as follows: the cooling water in the safety-grade water pool 111 is pumped by the water pump 113 and directed to the heat exchanger 114; the heat exchanger 114 transfers the high-temperature heat generated by the nuclear reactor to the cooling water, increasing the cooling water temperature; the high-temperature cooling water enters the cooling tower 112, releases heat through air dissipation or other heat dissipation methods, and cools the cooling water temperature; the cooled cooling water flows back into the safety-grade water pool 111, completing a cooling cycle. This ensures the continuous circulation of cooling water and efficient heat dissipation, thereby maintaining the normal operation of the nuclear reactor.

[0056] Among them, the design of the cooling tower 112 ensures that the cooling water can effectively dissipate heat, reducing the consumption of cooling water, thereby maintaining the cooling effect of the system. In addition, the heat exchanger 114 can also be connected to any other series 110 of safety-grade water pools 111. When a problem occurs with a water pool in a series 110, the water pools in other series 110 can provide a backup water source, thereby improving the redundancy and safety of the system and enhancing the flexibility and adaptability of the system. Through the coordinated work of the cooling tower 112, water pump 113 and heat exchanger 114, the system can efficiently perform cooling circulation, ensuring that the temperature of the cooling water always remains within a safe range. This not only improves the cooling efficiency of the system, but also reduces the energy consumption of the system, thereby improving the economy of the system.

[0057] See also Figure 1In some embodiments, each series 110 further comprises a first filter 115 and a second filter 116. The first filter 115 is arranged between the safety level water tank 111 and the water pump 113, and the second filter 116 is arranged between the water pump 113 and the heat exchanger 114. The first filter 115 is used to filter the cooling water drawn from the safety level water tank 111, remove impurities and suspended solids in the water, and ensure that the cooling water entering the water pump 113 is clean, preventing the water pump 113 from being clogged and damaged. The second filter 116 is used to filter the cooling water delivered from the water pump 113 to the heat exchanger 114, further removing small particles and impurities in the water, and ensuring that the cooling water entering the heat exchanger 114 is clean, preventing the heat exchanger 114 from being clogged and reducing the heat exchange efficiency. By arranging the first filter 115 and the second filter 116, the cleanliness of the cooling water is ensured, and the reliability and heat exchange efficiency of the system are improved. Clean cooling water can more effectively absorb the high-temperature heat generated by the nuclear reactor and quickly release heat through the cooling tower 112, ensuring the cooling effect of the system. Avoiding equipment damage due to water quality problems and reducing maintenance costs, thereby improving the economy, environmental protection and cooling efficiency of the system, reducing energy consumption, and further improving the environmental performance of the system.

[0058] In some embodiments, the nuclear power plant water system 100 further comprises a sewage device. The cooling water stored in the safety level water tank 111 and the non-safety level water tank 120 can be fresh water or seawater desalination water. In some embodiments, the sewage device can be configured to discharge sewage generated by the first filter 115, and the sewage generated by the first filter 115 is discharged through the sewage device, preventing the accumulation of pollutants affecting the normal operation of the system. Alternatively, sewage generated by the second filter 116 is discharged through the sewage device, ensuring that the cooling water entering the heat exchanger 114 is clean. Alternatively, sewage generated by the cooling tower 112 is discharged through the sewage device, which may

[0059] In some embodiments, the heat exchanger 114 of each series 110 is configured to be connected to the safety-grade water pool 111 of any other series 110. Specifically, the heat exchanger 114 of each series 110 can be connected not only to the safety-grade water pool 111 of the series 110, but also to the safety-grade water pool 111 of any other series 110. When a problem occurs with the water pool of a certain series 110, the safety-grade water pool 111 of other series 110 can allocate cooling water to the faulty series 110 through the heat exchanger 114 to ensure its cooling needs, thereby improving the redundancy and safety of the system. In some embodiments, the heat exchanger 114 of the faulty series 110 can be connected between the water pump 113 and the heat exchanger 114 of other series 110. Preferably, the heat exchanger 114 of the faulty series 110 is connected between the second filter 116 and the heat exchanger 114 of other series 110.

[0060] See also Figure 1 In some embodiments, the nuclear power plant water system 100 further includes a first connecting pipe 160 and a plurality of first isolation valves 130. The safety-level water tanks 111 are connected via the first connecting pipe 160, and the first isolation valve 130 is provided on the first connecting pipe 160 and configured to connect or isolate two connected safety-level water tanks 111. Specifically, the first connecting pipe 160 is used to connect the safety-level water tanks 111 so that the safety-level water tanks 111 are connected to each other in pairs. This ensures that when a problem occurs with a safety-level water tank 111 in a certain series 110, the safety-level water tanks 111 in other series 110 can provide a backup water source, thereby improving the redundancy and safety of the system. The provision of the first isolation valve 130 enables a safety-level water tank 111 to be isolated when necessary for repair or maintenance without affecting the normal operation of other series 110. The provision of first connecting pipe 160 and first isolation valve 130 ensures flexible allocation of cooling water, improving system reliability and ease of maintenance, extending system service life, and reducing system maintenance costs, thereby improving overall system performance. The design of first connecting pipe 160 and first isolation valve 130 also allows for flexible allocation of cooling water between different series 110, ensuring uniform distribution and efficient use of cooling water.

[0061] See also Figure 1In some embodiments, two first isolation valves 130 are provided between the two connected safety-level water tanks 111, namely the first valve and the second valve. The two connected safety-level water tanks 111 are the first water tank and the second water tank. The non-safety-level water tank 120 is connected to the first connecting pipe 160 between the first and second water tanks. Thus, the non-safety-level water tank 120 can replenish water to the first connecting pipe 160, and cooling water flows through the first connecting pipe 160 to the safety-level water tank 111 connected to the first connecting pipe 160. The first valve is configured to connect or isolate the first water tank from the non-safety-level water tank 120. When the first water tank needs to replenish cooling water, the first valve can be opened to introduce cooling water from the non-safety-level water tank 120 into the first water tank, ensuring the cooling water supply of the first water tank. The second valve is configured to connect or isolate the second water tank from the non-safety-level water tank 120. When the second water pool needs to be replenished with cooling water, the second valve can be opened to introduce cooling water from the non-safety-level water pool 120 into the second water pool to ensure the cooling water supply of the second water pool. This ensures the flexible allocation of cooling water and improves the reliability and maintenance convenience of the system. The design of the first valve and the second valve allows cooling water to be flexibly allocated between different series 110, ensuring the uniform distribution and efficient use of cooling water. This not only improves the cooling efficiency of the system, but also reduces system failures caused by insufficient cooling water, thereby improving the stability of the system. In addition, when a safety-level water pool 111 fails, it can be isolated from other water pools by the first valve and the second valve, so as not to affect the cooling water supply of other series 110.

[0062] In some embodiments, the nuclear power plant water system 100 further includes multiple second connecting pipes 170 . Each safety-class water tank 111 is connected to at least one second connecting pipe 170 , and each second connecting pipe 170 is connected to a non-safety-class water tank 120 . Specifically, second connecting pipes 170 are used to connect each safety-class water tank 111 with a non-safety-class water tank 120 , ensuring that cooling water can be replenished from the non-safety-class water tank 120 to any safety-class water tank 111 through the second connecting pipes 170 after the system has operated under the second operating condition for three days. The provision of second connecting pipes 170 ensures flexible allocation of cooling water, improving system reliability and emergency response capabilities.

[0063] In some embodiments, the nuclear power plant water system 100 further comprises a water replenishing device configured to replenish the cooling water for the safety class water tank 111 in the first working condition. Specifically, the water replenishing device is arranged in the system to replenish the cooling water for the safety class water tank 111 in the first working condition. This design ensures that the water amount of the safety class water tank 111 can be replenished in time in the low load working condition, maintaining the normal operation of the system. For example, when the water amount of the safety class water tank 111 is lower than a preset threshold, the water replenishing device is automatically started to draw the cooling water from an external water source and deliver it to the safety class water tank 111 through a pipeline, so as to ensure the continuous supply of the cooling water without consuming the water amount of the non-safety class water tank 120, improving the reliability and stability of the system. It should be noted that the system consumes very little cooling water in the low load working condition (i.e., the first working condition), and the arrangement of the water replenishing device can prevent the water amount of the safety class water tank 111 from being reduced to affect the cooling in the first three days of the operation of the system in the second working condition. In some embodiments, the water replenishing device can also be configured with a manual starting function to manually intervene in special cases to ensure the normal operation of the system.

[0064] Referring to Figure 1 In some embodiments, the nuclear power plant water system 100 further comprises a second isolation valve 140 arranged between the non-safety class water tank 120 and the safety class water tank 111 to control the communication or isolation between the safety class water tank 111 and the non-safety class water tank 120. Specifically, when the water amount of the safety class water tank 111 is insufficient, the cooling water of the non-safety class water tank 120 can be introduced into the safety class water tank 111 through the second isolation valve 140 to ensure the continuous supply of the cooling water. When the communication is not needed, the non-safety class water tank 120 and the safety class water tank 111 can be isolated through the second isolation valve 140 for maintenance or repair. By arranging the second isolation valve 140, the flexible allocation of the cooling water is ensured, and the reliability and maintenance convenience of the system are improved. In some embodiments, the second isolation valve 140 can be configured with a sensor and a control system, and when the control system detects that any series 110 is in the second working condition and the series 110 has been operated in the second working condition for three days, the second isolation valve 140 is automatically opened to introduce the cooling water of the non-safety class water tank 120 into the safety class water tank 111. The design of the second isolation valve 140 enables the flexible allocation of the cooling water in different working conditions, ensuring the uniform distribution and efficient utilization of the cooling water and reducing the waste of water resources.

[0065] Referring to Figure 1In some embodiments, the nuclear power plant water system 100 further includes a make-up water pump 150, which is positioned between the non-safety-rated water tank 120 and the safety-rated water tank 111. The make-up water pump 150 is configured to direct cooling water from the non-safety-rated water tank 120 to the safety-rated water tank 111. The make-up water pump 150 can also be positioned between connected safety-rated water tanks 111. The provision of the make-up water pump 150 ensures rapid cooling water replenishment when needed, improving system reliability and emergency response capabilities.

[0066] In some embodiments, the nuclear power plant water system 100 further includes a dosing device, which is configured to be able to add drugs to the safety-level water pool 111. The drugs include but are not limited to corrosion inhibitors, scale inhibitors, fungicides, and pH regulators, among which corrosion inhibitors include but are not limited to phosphates, nitrites, molybdates, chromates, hydrazine, and silicates. In some embodiments, the dosing device is equipped with a sensor and a control system. When it detects that the water quality parameters (such as pH value, dissolved oxygen, etc.) of the safety-level water pool 111 exceed the preset range, the dosing device automatically starts and adds an appropriate amount of drugs to the safety-level water pool 111 to ensure the stability of the water quality. By providing the dosing device, it is ensured that necessary chemicals can be added to the safety-level water pool 111 when needed to improve the water quality, prevent corrosion and scaling, improve the reliability and safety of the system, and extend the service life of the equipment.

[0067] In some embodiments, the nuclear power plant water system 100 comprises a plurality of non-safety level water pools 120 in communication with each other, each of the non-safety level water pools 120 is configured to be in communication with each of the safety level water pools 111, and the total amount of water stored in each of the non-safety level water pools 120 is sufficient to operate the system in the second operating mode for at least 27 days, wherein the number of the non-safety level water pools 120 is less than the number of the safety level water pools 111. Specifically, the number of the non-safety level water pools 120 is less than the number of the safety level water pools 111, but the total amount of water stored in each of the non-safety level water pools 120 is sufficient to operate the system in the second operating mode for at least 27 days, effectively reducing the overall water storage requirement, effectively avoiding the situation that water resources are idle or even wasted, and reducing the construction and maintenance costs of the water pools. For example, the nuclear power plant water system 100 is provided with two non-safety level water pools 120, which are in communication with each other to prevent the situation that when one of the non-safety level water pools 120 fails to supply water to the safety level water pool 111 due to the failure of the connection between the two, the reliability and safety of the system are effectively improved. Specifically, the provision of two (or even more) non-safety level water pools 120 can disperse risks, so that even if one of the non-safety level water pools 120 fails, the other one or more can continue to work, ensuring the reliability of the system. In addition, when any of the non-safety level water pools 120 needs to be repaired or cleaned, the water stored in the non-safety level water pool 120 that needs to be repaired or cleaned can be emptied into the other non-safety level water pool 120, without affecting the normal operation of the entire system.

[0068] Referring to Figure 2 The second aspect of the present application also provides a cooling method suitable for the nuclear power plant water system 100 described in any of the above embodiments and implementation modes. The cooling method comprises the following steps, but is not limited to the following steps:

[0069] When any one series 110 enters the second operating mode, for the sake of description, the safety level water pool 111 in the series 110 is defined as an accident water pool, and at least one other safety level water pool 111 in communication with the accident water pool is controlled to supply water to the accident water pool. This ensures that when the water in the accident water pool is insufficient, cooling water can be quickly supplied from other safety level water pools 111, thereby improving the reliability and emergency response capability of the system. In some embodiments, a plurality of other safety level water pools 111 can be simultaneously controlled to supply water to the accident water pool, further improving the water supply efficiency and stability of the system.

[0070] After the accident pool has operated for three days, the non-safety-grade water pool 120 is controlled to replenish water to the accident pool. This ensures a continuous supply of cooling water under prolonged, high-load conditions, further improving system reliability and stability. Furthermore, because the non-safety-grade water pool 120 stores enough water to sustain the system's operation under the second operating condition for at least 27 days, combined with the safety-grade water pool 111 to maintain a three-day supply, the system complies with nuclear power safety regulations.

[0071] In some embodiments, the non-safety-level water tank 120 is connected to the first connecting pipe 160. Therefore, when controlling the non-safety-level water tank 120 to replenish water to the accident water tank, the non-safety-level water tank 120 can be controlled to replenish water to the first connecting pipe 160 connecting the non-safety-level water tank 120 and the accident water tank, and by controlling the opening of the first valve or the second valve (when the connection and disconnection between the accident water tank and the other water tanks is controlled by the first valve, the first valve is opened. Similarly, when the connection and disconnection between the accident water tank and the other water tanks is controlled by the second valve, the second valve is opened), the cooling water in the non-safety-level water tank 120 quickly flows into the safety-level water tank 111, so as to ensure the continuous supply of cooling water under long-term high-load conditions, thereby improving the reliability and stability of the system.

[0072] In other embodiments, the non-safety-grade water tank 120 supplies water to the first connecting pipe 160 that connects the two safety-grade water tanks 111. Since the safety-grade water tanks 111 are connected to each other, the safety-grade water tank 111 can be connected to each other to supply water to the accident water tank. In one embodiment, the heat exchanger 114 in the same series 110 as the accident water tank can obtain sufficient water to cool the accident series 110 by connecting to the safety-grade water tank 111 of another series 110.

[0073] In some other embodiments, the non-safety-grade water pool 120 is directly connected to the safety-grade water pool 111 through the second connecting pipe 170. Therefore, after the accident water pool has been working for 3 days, the non-safety-grade water pool 120 can directly supply water to the accident water pool through the second connecting pipe 170 connected to the accident water pool.

[0074] See also Figure 3In some embodiments, each series 110 includes a cooling tower 112, a water pump 113, and a heat exchanger 114. The heat exchanger 114 is provided between the water pump 113 and the cooling tower 112, and the water pump 113 is connected to the safety-level water pool 111. For ease of expression, the heat exchanger 114 connected to the accident water pool is defined as the first heat exchanger 114. The cooling method further includes: when the accident water pool cannot supply water to the first heat exchanger 114, controlling the safety-level water pool 111 in at least one other series 110 to supply water to the first heat exchanger 114. This ensures that when the accident water pool is insufficient in water or the accident water pool fails, the first heat exchanger 114 of the series 110 where the accident water pool is located can still operate normally, thereby improving the reliability and emergency response capabilities of the system.

[0075] In some embodiments, if a blockage occurs between the accident water pool and the first heat exchanger 114 of the series 110 in which it is located, preventing the accident water pool from supplying cooling water to the first heat exchanger 114, the first heat exchanger 114 is connected between the second filter 116 and the heat exchanger 114 of any other series 110, thereby enabling the safety-level water pool 111 of the other series 110 to supply water to the first heat exchanger 114. After passing through the first heat exchanger 114, the cooling water flows to the cooling tower 112 of the series 110 in which the accident water pool is located. The cooling tower 112 treats the cooling water and discharges it to the accident water pool. The accident water pool is connected to the safety-level water pools 111 of the other series 110 via the first connecting pipe 160. In this manner, the system can ensure sufficient and effective use of cooling water during the first three days of operation in the first or second operating conditions. In other embodiments, when the connections between the accident water pool and the first heat exchanger 114 and the safety-grade water pools 111 of other series 110 fail, resulting in the accident water pool being unable to supply cooling water to the first heat exchanger 114, the first heat exchanger 114 is connected between the second filter 116 and the heat exchanger 114 of any other series 110, and the cooling tower 112 of the series 110 where the accident water pool is located is connected to the safety-grade water pool 111 of any other series 110. Therefore, when the cooling water of the safety-grade water pool 111 of any other series 110 flows to the cooling tower 112 of the series 110 where the first heat exchanger 114 is located through the first heat exchanger 114, the cooling tower 112 treats the cooling water and then discharges the cooling water to the safety-grade water pool 111 of any other series 110, thereby reducing the impact of the accident water pool on the system and ensuring that each series 110 can operate stably.

[0076] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0077] In addition, if the description of the present application involves "first", "second", etc., the description of "first", "second", etc. is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can be explicitly or implicitly included at least one of the features. In addition, if "and / or", "and / or", or "and / or" appears throughout the text, it means that the three parallel schemes include the A scheme, or the B scheme, or the A and B schemes are satisfied at the same time. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of the ordinary skilled in the art, when the combination of technical solutions appears contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist, nor is it within the scope of protection required by the present application.

[0078] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application, any equivalent structural transformation made under the inventive concept of the present application, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A water system for a nuclear power plant, characterized in that: include: Multiple series, each series is equipped with a safety-level water tank, each of the safety-level water tanks is connected to each other, each series has a first operating condition and a second operating condition, the water consumption of the series in the first operating condition is less than the water consumption of the series in the second operating condition, and the total water volume carried by any two of the safety-level water tanks is configured to be able to supply the system with water for at least 3 days of operation under the second operating condition; The non-safety-level water tank is configured to store at least enough water for the system to operate for 27 days under the second working condition. After the safety-level water tank has operated for 3 days under the second working condition, the non-safety-level water tank is connected to each of the safety-level water tanks.

2. The nuclear power plant water system according to claim 1, characterized in that: Each of the series includes a cooling tower, a water pump and a heat exchanger. The water pump is configured to be connected to the safety-level water pool and to guide the cooling water in the safety-level water pool to the heat exchanger. The heat exchanger is configured to transfer the high-temperature heat generated by the nuclear reactor to the cooling water. After passing through the heat exchanger, the cooling water enters the cooling tower to release heat and flows into the safety-level water pool again.

3. The water system for a nuclear power plant according to claim 2, characterized in that: Each of the series further includes a first filter and a second filter, wherein the first filter is arranged between the safety-grade water pool and the water pump, and the second filter is arranged between the water pump and the heat exchanger.

4. The water system for a nuclear power plant according to claim 3, characterized in that: The nuclear power plant water system further includes a sewage discharge device configured to discharge sewage generated by the first filter; and / or, The sewage discharge device is configured to discharge sewage generated by the second filter; and / or, The sewage discharge device is configured to discharge sewage generated by the cooling tower.

5. The water system for a nuclear power plant according to claim 2, characterized in that: The heat exchangers in each series are configured to be able to communicate with the safety-grade water pools in any other series.

6. The water system for a nuclear power plant according to claim 1, characterized in that: The nuclear power plant water system also includes a first connecting pipe and multiple first isolation valves. The safety-level water pools are connected through the first connecting pipe. The first isolation valve is arranged on the first connecting pipe and is configured to connect or isolate two connected safety-level water pools.

7. The water system for a nuclear power plant according to claim 6, characterized in that: Two first isolation valves are provided between the two connected safety-level water pools, namely the first valve and the second valve. The two connected safety-level water pools are respectively the first water pool and the second water pool. The non-safety-level water pool is connected to the first connecting pipe between the first water pool and the second water pool. The first valve is configured to connect or isolate the first water pool and the non-safety-level water pool, and the second valve is configured to connect or isolate the second water pool and the non-safety-level water pool.

8. The water system for a nuclear power plant according to claim 1, characterized in that: The nuclear power plant water system further includes a plurality of second connecting pipes, each of the safety-level water pools is connected to at least one of the second connecting pipes, and each of the second connecting pipes is connected to the non-safety-level water pool.

9. The water system for a nuclear power plant according to claim 1, characterized in that: The nuclear power plant water system also includes a second isolation valve, which is arranged between the non-safety-level water pool and the safety-level water pool and is used to control the connection or isolation between the safety-level water pool and the non-safety-level water pool.

10. The water system for a nuclear power plant according to claim 1, wherein: The water system of the nuclear power plant further includes a water replenishment device, which is configured to replenish cooling water for the safety-level water pool operating under the first operating condition.

11. The water system for a nuclear power plant according to claim 1, wherein: The nuclear power plant water system further includes a water supply pump, which is arranged between the non-safety-grade water pool and the safety-grade water pool, and is configured to guide cooling water from the non-safety-grade water pool to the safety-grade water pool; and / or The water replenishment pump is arranged between the connected safety-level water pools.

12. The water system for a nuclear power plant according to claim 1, wherein: The nuclear power plant water system further includes a drug dosing device configured to deliver drugs into the safety-grade water pool.

13. A cooling method, applicable to the water system of a nuclear power plant according to any one of claims 1 to 12, characterized in that: The cooling method comprises: When any one of the series enters the second working condition, the safety-level water pool in the series becomes an emergency water pool, and at least one other safety-level water pool connected to the emergency water pool is controlled to replenish water to the emergency water pool; After the accident water pool has been operating for 3 days, the non-safety-level water pool is controlled to replenish water to the accident water pool.

14. The cooling method according to claim 13, wherein: When controlling the non-safety level water pool to replenish water to the accident water pool, The non-safety-level water pool supplies water to a second connecting pipe connecting the non-safety-level water pool and the accident water pool; Alternatively, the non-safety-grade water pool supplies water to a first connecting pipe connecting the two safety-grade water pools.

15. The cooling method according to claim 13, wherein: Each of the series includes a cooling tower, a water pump, and a heat exchanger, wherein the heat exchanger is provided between the water pump and the cooling tower, and the water pump is connected to the safety-level water pool, wherein the heat exchanger connected to the emergency water pool is the first heat exchanger, and the cooling method further includes: After any one of the series enters the second operating condition and the emergency water pool is unable to supply cooling water to the first heat exchanger, the safety-level water pool in at least one other series is controlled to supply water to the first heat exchanger.

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