Water system for nuclear power plant and cooling method

Abstract

The invention 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 pools, each series is provided with a safety-level pool, the safety-level pools are communicated pairwise, and each series has a first working condition and a second working condition; the sum of the water quantity borne by any two safety-level pools can be at least used for the system to operate for 3 days under the second working condition. The non-safety-level water pool can at least store water for the system to operate for 27 days under the second working condition. 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, idling and waste of the water resources are avoided, the requirement for the total water storage amount is effectively reduced, and therefore the building and maintaining cost of the water pool is reduced. Reduction of the total water storage capacity of the nuclear power plant means that occupation and consumption of land and water resources in the pool building process 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 meet the conditions 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 amount of 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] Since the final heat sink system is usually composed of several mutually redundant series, the relevant design usually adopts that each series is equipped with a water tank with a storage capacity of 30 days, and these water tanks are isolated from each other. That is, in the traditional design, the total volume of the system water tank is the number of series multiplied by the water volume required for 30 days under a single series accident. Although this design method meets the regulatory requirements, it greatly increases the project cost. Summary of the invention

[0004] The main purpose of the present invention is to provide 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 for a nuclear power plant while ensuring that the nuclear power plant has sufficient water.

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

[0006] Multiple series, each of which is equipped with a safety-level water tank, each of which is connected to each other, each of which has a first working condition and a second working condition, and the total amount of water 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 working 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-grade water pool and the non-safety-grade water pool of the nuclear power plant water system 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-grade water pools provide 3 days of water consumption, and the non-safety-grade water pool provides 27 days of water consumption). It should be noted that although the water volume required for the entire system for 30 days of accidents will be greater than the water volume required for a single series for 30 days, compared with the related art in which each series is separately equipped with the water volume required for the series to operate for 30 days under accident conditions, the water volume of the nuclear power plant water system of the present application is much smaller than the total volume of the system in the traditional design (total volume in the traditional design = number of series multiplied by the water volume required for 30 days under a single series accident). At the same time, in the nuclear power plant water system of the present application, the volume of the safety-grade water pool of each series is smaller, and the volume of each safety-grade water pool is greatly reduced, thereby reducing the engineering construction and maintenance costs of each safety-grade 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 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.

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

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

[0012] and / or,

[0013] The sewage discharge device is configured to discharge sewage generated by the second filter;

[0014] and / or,

[0015] The sewage discharge device is configured to discharge sewage generated by the cooling tower.

[0016] In some embodiments, each of the series of heat exchangers is configured to be connected to any other series of the safety-grade water pools.

[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 tanks 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 tanks.

[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 be able to connect or isolate the first water pool and the non-safety-level water pool, and the second valve is configured to be able to connect or isolate 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 of the second connecting pipes, 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 also 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 water system of the nuclear power plant further comprises a water supply pump, the water supply pump is arranged between the non-safety-level water pool and the safety-level water pool, and the water supply pump is configured to guide the cooling water of the non-safety-level water pool to the safety-level 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, which is configured to deliver drugs into the safety-grade water pool.

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

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

[0028] After the accident water pool has been in operation 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 replenishes 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, the heat exchanger is arranged between the water pump and the cooling tower, the water pump is connected to the safety-level water pool, wherein the heat exchanger connected to the accident 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 accident water pool is unable to supply water to the first heat exchanger, the safety-level water pool in at least one other of the 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 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 working condition and a second working condition. Among them, the total amount of water carried by any two safety-level water pools can supply the system to operate for at least 3 days under the second working condition. Therefore, when a certain safety-level water pool fails, the safety-level water pools of other series can support the work of the series where the safety-level water pool fails, reducing the impact on the cooling capacity of the entire nuclear power plant. In addition, when a certain series is in the second working condition, the design of each safety-level water pool being connected to each other in pairs enables the water source of other safety-level water pools to be allocated to the series in the second working 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 pools 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 reduces the construction and maintenance costs of safety-level water pools, saves water resources, and ensures sufficient cooling water, effectively reducing safety hazards.

[0035] In addition, the non-safety-level water pool in this application can store at least 27 days of water for the system to operate under the second working condition. Compared with the relevant technology that each series is equipped with a water pool with a storage capacity of 30 days to meet regulatory requirements, the overall water storage demand is effectively reduced, thereby reducing the construction and maintenance costs of the water pool. In addition, since not all series will be in the second working condition at the same time during the operation of the nuclear power plant, 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, avoiding the idleness and waste of water resources. The reduction in the overall water storage capacity of the nuclear power plant means that the occupation and consumption of land and water resources during the construction of the water pool are reduced. This helps to reduce the impact of nuclear power plant construction on the surrounding environment and improves the feasibility of environmental protection and sustainable development. It should be noted that although the design of this application is lower than the total water storage capacity of the system in the traditional design in terms of total water storage, the 27-day water storage capacity of the non-safety-level water pool combined with the 3-day water storage capacity of the safety-level water pool can still meet the regulatory requirements for the safe operation of the nuclear power plant. 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0037] Figure 1 This is a schematic diagram of the structure of a water system for a nuclear power plant in one embodiment of the present invention;

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

[0039] Figure 3 Schematic diagram of a cooling method in 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 pool 120;

[0044] A first isolation valve 130;

[0045] A second isolation valve 140;

[0046] Make-up water pump 150;

[0047] A first connecting pipe 160;

[0048] The second connecting pipe 170 .

[0049] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] In the related art, seawater is usually used to cool nuclear power plant equipment. However, since the cooling tower will cause water droplets to be blown away during the heat exchange process of the seawater carrying heat, the salt in the seawater will stick to the equipment, causing the structure of each equipment to be corroded and even causing environmental problems. Therefore, desalinated water is used as the working medium in some mature designs. 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, and the process of seawater desalination consumes a lot of energy. 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 huge transportation cost to introduce desalinated water to inland nuclear power plants). If fresh water is used directly to cool a nuclear power plant built inland, since the cooling system of the nuclear power plant needs to consume a huge amount of fresh water, the cooling water source of the nuclear power plant will be insufficient, which will increase the safety risks of the nuclear power plant. In addition, in the design of the cooling system for nuclear power plants in the related art, a water tank is usually set up in each series that can store water for at least 30 days of operation of the series under high load conditions. This results in a huge water consumption for the entire system. Fresh water resources are already scarce. The use of the cooling system in the related art will seriously lead to a shortage of cooling water, resulting in extremely high safety hazards in the system. Moreover, in the related art, each series is equipped with a water tank that can store at least 30 days of water, which will seriously increase the cost of building and maintaining the water tank, and will also occupy too much land resources.

[0052] For this reason, please see Figure 1The present invention provides a water system 100 for a nuclear power plant, comprising a plurality of series 110 and a non-safety-level water pool 120. Each series 110 is equipped with a safety-level water pool 111, and each safety-level water pool 111 is connected to each other. Each series 110 has a first working condition and a second working condition. In some embodiments, the cooling water source of the series 110 in the first working condition can be provided by the safety-level water pool 111, or by other external water sources, and the cooling water source of the series 110 in the second working condition can also be provided by the safety-level water pool 111. It should be noted that, in some embodiments, the series 110 in the first working condition can be in a normal operating state, and the series 110 in the second working condition can be in an abnormal operating state (including earthquakes and loss of external power supply, etc.). For ease of understanding, the following description is made by taking the system in a high-load operating state as the second working condition as an example. Among them, the water consumption of the series 110 in the first working condition is supplemented by an external water replenishment system. The total amount of water carried by any two safety-level water pools 111 is configured to be able to supply the system with at least 3 days of operation in the second working condition.

[0053] Specifically, each series 110 is equipped with a safety-level water pool 111, and these safety-level water pools 111 are connected in pairs through pipes to form a redundant water supply network. In order to ensure sufficient cooling water supply under the second working condition, the total water volume of any two safety-level water pools 111 can supply the system with at least 3 days of operation under the second working condition, ensuring that in an emergency, the system can have sufficient cooling water supply to maintain sufficient cooling capacity to cope with short-term failures or power outages and other problems, reduce safety hazards, and thus ensure the safe operation of the nuclear power plant. In addition, the nuclear power plant water system 100 also includes a non-safety-level water pool 120. The non-safety-level water pool 120 is configured to store at least 27 days of water for the system to operate under the second working condition. After the safety-level water pool 111 has worked for 3 days under the second working condition, the non-safety-level water pool 120 can be connected to each safety-level water pool 111 through a pipe, thereby providing additional cooling water to each series 110, ensuring that the system can continue to provide sufficient cooling water during long-term high-load operation, thereby ensuring the normal operation of the nuclear power plant. Compared with the related art that each series is equipped with a water pool with a storage capacity of 30 days to meet regulatory requirements, the overall water storage demand is effectively reduced, thereby reducing the number of water pools to be built and the maintenance cost. It should be noted that the reduction in the overall water storage capacity of the nuclear power plant means that the occupation and consumption of land and water resources during the construction of the water pool is reduced, which helps to protect the ecological environment. That is, the solution of this application not only meets the requirements of nuclear power safety regulations, but also optimizes the use of water resources and reduces the cost of the project.

[0054] Each series 110 is equipped with a safety-level water pool 111, and each safety-level water pool 111 is connected to each other in pairs. This allows the safety-level water pools 111 of other series 110 to provide backup water sources when a problem occurs in a safety-level water pool 111 of a series 110, thereby improving the redundancy and safety of the system. Exemplarily, 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 each safety-level water pool 111 being connected to each other in pairs allows the water sources of other safety-level water pools 111 to be allocated to the series 110 in the second operating condition, so as to ensure the rapid supply of cooling water, thereby 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 be connected to the safety-level water pool 111 and to guide the cooling water in the safety-level 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 to release heat and flows into the safety-level water pool 111 again. Specifically, the cooling process of each series 110 is as follows: the cooling water in the safety-level water pool 111 is extracted by the water pump 113 and guided to the heat exchanger 114; the heat exchanger 114 transfers the high-temperature heat generated by the nuclear reactor to the cooling water, so that the temperature of the cooling water increases; the high-temperature cooling water enters the cooling tower 112, releases heat through air heat dissipation or other heat dissipation methods, and reduces the temperature of the cooling water; the cooled cooling water flows into the safety-level water pool 111 again, completing a cooling cycle. This ensures 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 the safety-level water pool 111. When a problem occurs in a water pool of a series 110, the water pools of 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, the water pump 113 and the heat exchanger 114, the system can efficiently perform cooling cycles to ensure that the temperature of the cooling water is always kept 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 includes a first filter 115 and a second filter 116. The first filter 115 is disposed between the safety-level water pool 111 and the water pump 113, and the second filter 116 is disposed between the water pump 113 and the heat exchanger 114. The first filter 115 is used to filter the cooling water extracted from the safety-level water pool 111, remove impurities and suspended matter in the water, ensure that the cooling water entering the water pump 113 is clean, and prevent the water pump 113 from being blocked or damaged. The second filter 116 is used to filter the cooling water transported from the water pump 113 to the heat exchanger 114, further remove tiny particles and impurities in the water, ensure that the cooling water entering the heat exchanger 114 is clean, and prevent the heat exchanger 114 from being blocked and reducing the heat exchange efficiency. By providing 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 the heat through the cooling tower 112, ensuring the cooling effect of the system. It avoids equipment damage caused by water quality problems and can reduce 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 water system 100 of the nuclear power plant further includes a sewage discharge device. The cooling water stored in the safety-grade water pool 111 and the non-safety-grade water pool 120 may be fresh water or desalinated seawater. In some embodiments, the sewage discharge device may be configured to discharge the sewage generated by the first filter 115, and the sewage generated by the first filter 115 is discharged through the sewage discharge device to prevent the accumulation of pollutants from affecting the normal operation of the system. Alternatively, the sewage generated by the second filter 116 is discharged, and the sewage generated by the second filter 116 is discharged through the sewage discharge device to ensure that the cooling water entering the heat exchanger 114 is clean. Alternatively, the sewage generated by the cooling tower 112 is discharged, and the cooling tower 112 may generate sewage containing impurities during the heat dissipation process, and these sewage are discharged through the sewage discharge device to prevent pollution of the cooling water system. In other embodiments, the sewage discharge device may also be configured to process and discharge the sewage generated by the first filter 115, the second filter 116, the cooling tower 112 and other equipment. Among them, by setting up the sewage discharge device, it is ensured that the sewage generated in the system can be discharged in time, and the accumulation of pollutants is prevented from affecting the normal operation of the system, thereby improving the reliability and cooling efficiency of the system.

[0059] In some embodiments, the heat exchanger 114 of each series 110 is configured to be connected to the safety-level 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-level water pool 111 of the series 110, but also to the safety-level water pool 111 of any other series 110. When a problem occurs in the water pool of a certain series 110, the safety-level 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. Each safety-level water pool 111 is connected via the first connecting pipe 160, and the first isolation valve 130 is disposed on the first connecting pipe 160 and configured to enable the two connected safety-level water pools 111 to be connected or isolated. Specifically, the first connecting pipe 160 is used to connect each safety-level water pool 111 so that each safety-level water pool 111 is connected to each other in pairs. This ensures that when a problem occurs with a safety-level water pool 111 of a certain series 110, the safety-level water pools 111 of 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 pool 111 to be isolated when necessary for repair or maintenance without affecting the normal operation of other series 110. By providing the first connecting pipe 160 and the first isolating valve 130, the flexible allocation of cooling water is ensured, the reliability and maintenance convenience of the system are improved, the service life of the system is extended, and the system maintenance cost is reduced, thereby improving the overall performance of the system. The design of the first connecting pipe 160 and the first isolating valve 130 also allows the cooling water to be flexibly allocated between different series 110, ensuring the uniform distribution and efficient use of the cooling water.

[0061] See also Figure 1In some embodiments, two first isolation valves 130 are provided between the two connected safety-level water pools 111, namely the first valve and the second valve. The two connected safety-level water pools 111 are the first water pool and the second water pool. The non-safety-level water pool 120 is connected to the first connecting pipe 160 between the first water pool and the second water pool, so that the non-safety-level water pool 120 can replenish water to the first connecting pipe 160, and the cooling water flows to the safety-level water pool 111 connected to the first connecting pipe 160 through the first connecting pipe 160. The first valve is configured to connect or disconnect the first water pool and the non-safety-level water pool 120. When the first water pool needs to replenish cooling water, the first valve can be opened to introduce the cooling water of the non-safety-level water pool 120 into the first water pool to ensure the cooling water supply of the first water pool. The second valve is configured to connect or disconnect the second water pool and the non-safety-level water pool 120. When the second water pool needs to be supplemented with cooling water, the cooling water of the non-safety-level water pool 120 can be introduced into the second water pool by opening the second valve to ensure the cooling water supply of the second water pool. Flexible allocation of cooling water is ensured, and the reliability and maintenance convenience of the system are improved. 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. Not only does it improve the cooling efficiency of the system, it 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 a plurality of second connecting pipes 170, each safety-level water pool 111 is connected to at least one second connecting pipe 170, and each second connecting pipe 170 is connected to the non-safety-level water pool 120. Specifically, the second connecting pipe 170 is used to connect each safety-level water pool 111 and the non-safety-level water pool 120, ensuring that after the system has been running for 3 days under the second operating condition, cooling water can be replenished from the non-safety-level water pool 120 to any safety-level water pool 111 through the second connecting pipe 170. By providing the second connecting pipe 170, the flexible allocation of cooling water is ensured, and the reliability and emergency response capability of the system are improved.

[0063] In some embodiments, the water supply system 100 of the nuclear power plant further includes a water replenishment device, which is configured to replenish cooling water for the safety-level water pool 111 operating under the first working condition. Specifically, the water replenishment device is arranged in the system to replenish cooling water for the safety-level water pool 111 under the first working condition. This design ensures that the water volume of the safety-level water pool 111 can be replenished in time under low-load conditions to maintain the normal operation of the system. Exemplarily, when the water volume of the safety-level water pool 111 is lower than the preset threshold, the water replenishment device automatically starts, extracts cooling water from an external water source, and transports it to the safety-level water pool 111 through a pipeline to ensure the continuous supply of cooling water while not consuming the water volume of the non-safety-level water pool 120, thereby improving the reliability and stability of the system. It should be noted that the system consumes very little cooling water under low-load conditions (i.e., the first working condition), and the setting of the water replenishment device can prevent the water volume of the safety-level water pool 111 from decreasing and affecting the cooling of the system in the first three days of operation under the second working condition. In some embodiments, the water replenishment device can also be configured with a manual start function so that manual intervention can be performed in special circumstances to ensure the normal operation of the system.

[0064] See also Figure 1 In some embodiments, the nuclear power plant water system 100 further includes a second isolation valve 140, which is disposed between the non-safety-level water pool 120 and the safety-level water pool 111, and is used to control the connection or isolation between the safety-level water pool 111 and the non-safety-level water pool 120. Specifically, when the amount of water in the safety-level water pool 111 is insufficient, the cooling water of the non-safety-level water pool 120 can be introduced into the safety-level water pool 111 through the second isolation valve 140 to ensure a continuous supply of cooling water. When no connection is required, the non-safety-level water pool 120 can be isolated from the safety-level water pool 111 through the second isolation valve 140 for repair or maintenance. By providing the second isolation valve 140, the flexible allocation of cooling water is ensured, and the reliability and maintenance convenience of the system are improved. In some embodiments, the second isolation valve 140 may be configured with a sensor and a control system. When the control system detects that any series 110 is in the second working condition and the series 110 has been working in the second working condition for 3 days, the second isolation valve 140 is automatically opened to introduce the cooling water of the non-safety-level water pool 120 into the safety-level water pool 111. The design of the second isolation valve 140 allows the cooling water to be flexibly allocated under different working conditions, ensuring the uniform distribution and efficient use of the cooling water and reducing the waste of water resources.

[0065] See also Figure 1In some embodiments, the nuclear power plant water system 100 further includes a water supply pump 150, which is disposed between the non-safety-level water pool 120 and the safety-level water pool 111, and the water supply pump 150 is configured to guide the cooling water of the non-safety-level water pool 120 to the safety-level water pool 111. The water supply pump 150 may also be disposed between connected safety-level water pools 111. By providing the water supply pump 150, it is ensured that cooling water can be quickly replenished when needed, thereby improving the reliability and emergency response capability of the system.

[0066] In some embodiments, the nuclear power plant water system 100 also includes a dosing device, which is configured to be able to put medicine into the safety-level water pool 111. The medicine includes but is not limited to corrosion inhibitors, scale inhibitors, bactericides, and pH regulators, etc., wherein the corrosion inhibitors include but are not limited to phosphates, nitrites, molybdates, chromates, hydrazine, and silicates, etc. In some embodiments, the dosing device is equipped with a sensor and a control system. When it is detected 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 to put an appropriate amount of medicine into the safety-level water pool 111 to ensure the stability of the water quality. By setting up the dosing device, it is ensured that necessary chemicals can be added to the safety-level water pool 111 when necessary 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 water system 100 of a nuclear power plant includes a plurality of non-safety-level water tanks 120 that are interconnected, each non-safety-level water tank 120 is configured to be able to connect to each safety-level water tank 111, and the total amount of water stored in each non-safety-level water tank 120 is sufficient to supply the system to operate for at least 27 days under the second operating condition, wherein the number of non-safety-level water tanks 120 is less than the number of safety-level water tanks 111. Specifically, the number of non-safety-level water tanks 120 is less than the number of safety-level water tanks 111, but the total amount of water stored in each non-safety-level water tank 120 is sufficient to supply the system to operate for at least 27 days under the second operating condition, effectively reducing the overall water storage demand, effectively avoiding the situation where water resources are idle or even wasted, and reducing the construction and maintenance costs of the water tanks. Exemplarily, the water system 100 of a nuclear power plant is provided with two non-safety-level water pools 120, which are connected to each other to prevent the situation where the water of the non-safety-level water pool 120 cannot be supplied to the safety-level water pool 111 when the connection between one of them and the safety-level water pool 111 fails, thereby effectively improving the reliability and safety of the system. Specifically, setting up two (or even more) non-safety-level water pools 120 can disperse risks. Even if one of the non-safety-level water pools 120 fails, the other one or more can continue to work to ensure the reliability of the system. In addition, when it is necessary to repair or clean any of the non-safety-level water pools 120, the water stored in the non-safety-level water pool 120 that needs to be repaired or cleaned can be emptied to other non-safety-level water pools 120 without affecting the normal operation of the entire system.

[0068] See also Figure 2 The second aspect of the present invention further provides a cooling method, which is applicable to the nuclear power plant water system 100 described in any of the above embodiments and implementation methods. The cooling method includes but is not limited to the following steps:

[0069] When any series 110 enters the second working condition, for ease 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 connected to the accident water pool is controlled to replenish water to the accident water pool. This ensures that when the water volume of the accident water pool is insufficient, cooling water can be quickly replenished from other safety-level water pools 111, thereby improving the reliability and emergency response capability of the system. In some embodiments, multiple other safety-level water pools 111 can be controlled to replenish water to the accident water pool at the same time, further improving the water replenishment efficiency and the stability of the system.

[0070] After the accident pool has been working for 3 days, the non-safety-level pool 120 is controlled to replenish water to the accident pool. This ensures the continuous supply of cooling water under long-term high-load conditions, further improving the reliability and stability of the system. In addition, since the non-safety-level pool 120 stores at least enough water for the system to operate for 27 days under the second operating condition, combined with the safety-level pool 111 to maintain the water volume of the system to operate for 3 days under the second operating condition, the system meets the requirements of 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 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 pool 120 replenishes water to the first connecting pipe 160 connecting two safety-grade water pools 111. Since the safety-grade water pools 111 are connected to each other, the accident water pool can be replenished with water through the interconnected characteristics of the safety-grade water pools 111. In one embodiment, the heat exchanger 114 of the same series 110 as the accident water pool can obtain sufficient water to cool the accident series 110 through the safety-grade water pools 111 connected to other 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 disposed 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 description, the heat exchanger 114 connected to the accident water pool is defined as the first heat exchanger 114. The cooling method also 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. It ensures that when the accident water pool is short of 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 work normally, thereby improving the reliability and emergency response capability of the system.

[0075] In some embodiments, when a blockage occurs between the accident water pool and the first heat exchanger 114 of the series 110 to which it belongs, so that the accident water pool cannot 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, so that the safety-level water pool 111 of the other series 110 can supply water to the first heat exchanger 114. The cooling water flows to the cooling tower 112 of the series 110 where the accident water pool is located after passing through the first heat exchanger 114, and 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 pool 111 of other series 110 through the first connecting pipe 160, so that in this way, when the system is running in the first working condition or the first three days of the second working condition, it can ensure sufficient and effective use of cooling water. In other embodiments, when the connection between the accident water pool and the first heat exchanger 114 and the safety-grade water pools 111 of other series 110 fails and the accident water pool cannot 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 processes the cooling water and discharges the cooling water to the safety-grade water pool 111 of any other series 110, so as to reduce the impact of the accident water pool on the system and ensure 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 in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0077] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or", "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0078] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A water system for a nuclear power plant, characterized in that: include: A plurality of series, each of which is equipped with a safety-level water tank, each of which is connected to each other, each of which has a first working condition and a second working condition, the water consumption of the series in the first working condition is less than the water consumption of the series in the second working condition, and the total amount of water 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 working 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 water system for a nuclear power plant 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 disposed between the safety-grade water pool and the water pump, and the second filter is disposed 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 comprises a sewage discharge device, wherein the sewage discharge device is 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 connected to 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 a plurality of first isolation valves. The safety-level water tanks are connected via the first connecting pipe. The first isolation valve is disposed on the first connecting pipe and is configured to connect or isolate two connected safety-level water tanks.

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 be able to connect or isolate the first water pool and the non-safety-level water pool. The second valve is configured to be able 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 also 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, characterized in that: The water system of the nuclear power plant also 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, characterized in that: The water system of the nuclear power plant further comprises a water supply pump, which is arranged between the non-safety-grade water pool and the safety-grade water pool, and the water supply pump is configured to guide the cooling water of 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, characterized in that: The nuclear power plant water system also includes a drug adding device, which is configured to be able to add drugs to the safety-level 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 is an accident water pool, and at least one other safety-level water pool connected to the accident water pool is controlled to replenish water to the accident water pool; After the accident water pool has been in operation 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, characterized in that: 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; Alternatively, the non-safety-grade water pool replenishes water to a first connecting pipe connecting the two safety-grade water pools.

15. The cooling method according to claim 13, characterized in that: 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 accident water pool is a 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.

Images