Gas content adjusting method and device and important service water system of nuclear power plant

Abstract

The invention discloses a gas content adjusting method and device and an important service water system of a nuclear power plant. The method comprises the following steps: acquiring overall parameters of the important service water system and gas volume detection parameters of a local high point pipeline of the important service water system; and obtaining the gas exhaustion rate in water according to the gas accumulation amount detection parameters of the local high-point pipeline. And obtaining the total gas content in the important service water system according to the total parameters of the important service water system and the gas exhaustion rate in water. And performing exhaust operation on a local high point pipeline in the system according to the total gas content in the system. The gas content adjusting method can effectively reduce gas accumulation in an important service water system.

Description

Technical Field

[0001] The present invention specifically relates to a gas content adjustment method, device and important component cooling water system of a nuclear power plant. Background Art

[0002] As a nuclear safety class system of a nuclear power plant, the important component cooling water system functions to transfer the heat load collected by the component cooling water system to the ultimate heat sink - seawater. The technological process of the important component cooling water system is as follows: water is taken after being filtered by the rotary screen of the circulating water filtration system located in the combined pump house, and cooling water is provided to the plate heat exchanger located in the nuclear island building through the intake corridor of the important component cooling water system. The drained water is discharged into the drainage pipeline of the important component cooling water system through the overflow well of the important component cooling water system outside the nuclear island building, then converges to the siphon well, and finally discharged into the sea.

[0003] However, during long-term pump shutdown of the important component cooling water system, pressure fluctuations will occur in the main pipe. The pressure fluctuations in the main pipe are likely to cause pipeline fatigue, cracks or even rupture, thus triggering water leakage or pipe burst accidents. Among them, the gas accumulation in the important component cooling water system itself and the gas-liquid two-phase flow formed by the air precipitated from seawater are one of the important reasons for the pressure fluctuations in the main pipe of the nuclear power plant.

[0004] At present, there is no feasible means to solve the problem of gas accumulation in the important component cooling water system of nuclear power plants. Therefore, how to discharge and reduce the gas accumulation in the important component cooling water system of nuclear power plants has become a technical problem to be solved urgently. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a gas content adjustment method, device and important component cooling water system of a nuclear power plant aiming at the above deficiencies existing in the prior art. This method can effectively reduce the gas accumulation in the important component cooling water system.

[0006] According to an embodiment of the first aspect of the present invention, a gas content adjustment method is provided for adjusting the gas content of the important component cooling water system, including the following steps:

[0007] Obtain the overall parameters of the important component cooling water system and the gas accumulation detection parameters of the local high-point pipeline of the important component cooling water system;

[0008] Obtain the gas precipitation rate in water according to the gas accumulation detection parameters of the local high-point pipeline;

[0009] Obtain the total gas content rate in the important component cooling water system according to the overall parameters of the important component cooling water system and the gas precipitation rate in water;

[0010] Perform exhaust operation on the local high-point pipeline in the important component cooling water system according to the total gas content rate in the important component cooling water system.

[0011] Preferably, the gas accumulation detection parameters of the local high-point pipeline include: local accumulated gas volume and local gas-containing volume;

[0012] Based on the gas accumulation detection parameters of the local high-point pipeline, the gas precipitation rate in water is obtained, specifically:

[0013] Based on the local accumulated gas volume and the local gas-containing volume, the gas precipitation rate in water is calculated.

[0014] Preferably, calculating the gas precipitation rate in water based on the local accumulated gas volume and the local gas-containing volume further includes:

[0015] Based on the local accumulated gas volume and the local gas-containing volume, a first calculation equation is established;

[0016] The first calculation equation is:

[0017]

[0018] Based on the first calculation equation, the gas precipitation rate in water is calculated.

[0019] Preferably, the overall parameters of the important plant water system include: the overall volume of the important plant water system and the total gas-containing volume;

[0020] Based on the overall volume parameter of the important plant water system and the gas precipitation rate in water, the total gas content rate in the important plant water system is obtained, specifically:

[0021] Based on the overall volume of the important plant water system, the total gas-containing volume, and the gas precipitation rate in water, the gas content rate in the important plant water system is calculated.

[0022] Preferably, calculating the gas content rate in the important plant water system based on the overall volume of the important plant water system, the total gas-containing volume, and the gas precipitation rate in water further includes:

[0023] Based on the overall volume of the important plant water system, the total gas-containing volume, and the gas precipitation rate in water, a second calculation equation is established;

[0024] The second calculation equation is:

[0025]

[0026] Based on the second calculation equation, the gas content rate in the important plant water system is calculated.

[0027] Preferably, exhausting the local high-point pipeline in the important plant water system based on the total gas content rate in the important plant water system specifically includes:

[0028] Determine whether the total gas content rate in the important service water system is lower than or equal to a preset threshold:

[0029] If so, determine that the total gas content rate in the important service water system meets the requirements;

[0030] If not, exhaust the air from the pipeline at the local high point until the total gas content rate in the important service water system is lower than or equal to the preset threshold.

[0031] Preferably, before exhausting the air from the pipeline at the local high point in the important service water system according to the total gas content rate in the important service water system, it further includes:

[0032] Obtain the working state of the important service water system, and the working state of the important service water system is the operating state or the shutdown state;

[0033] According to the working state of the important service water system, determine to execute the first water conveyance step or the second water conveyance step for the important service water system:

[0034] When the working state of the important service water system is the operating state, execute the first water conveyance step;

[0035] When the working state of the important service water system is the shutdown state, execute the second water conveyance step.

[0036] Preferably, the first water conveyance step includes:

[0037] Divert the cooling water input into the important service water system to obtain the first part of the cooling water and the second part of the cooling water,

[0038] wherein, the first part of the cooling water directly enters the important service water system,

[0039] The second part of the cooling water is subjected to gas-liquid separation to obtain preliminarily degassed water, and the preliminarily degassed water is stored, and the first water conveyance step ends;

[0040] The second water conveyance step includes: inputting the preliminarily degassed water into the important service water system, and the second water conveyance step ends.

[0041] According to an embodiment of the second aspect of the present invention, a gas content regulating device is provided for regulating the gas content of an important plant water system, including: a parameter acquisition unit, a first calculation unit, a second calculation unit, and a regulation unit; the parameter acquisition unit is configured to acquire the overall parameters of the important plant water system and the gas accumulation detection parameters of the local high-point pipeline of the important plant water system; the first calculation unit is electrically connected to the parameter acquisition unit and is configured to obtain the gas precipitation rate in water according to the gas accumulation detection parameters of the local high-point pipeline; the second calculation unit is electrically connected to the parameter acquisition unit and the first calculation unit respectively, and is configured to obtain the total gas content rate in the important plant water system according to the overall parameters of the important plant water system and the gas precipitation rate in water; the regulation unit is electrically connected to the second calculation unit and is configured to perform an exhaust operation on the local high-point pipeline in the important plant water system according to the total gas content rate in the important plant water system.

[0042] Preferably, the regulation unit includes a first analysis module and an exhaust device; the first analysis module is configured to judge whether the total gas content rate in the important plant water system is lower than or equal to a preset threshold: if so, it is determined that the total gas content rate in the important plant water system meets the requirements; if not, an exhaust signal is sent; the exhaust device is electrically connected to the analysis module and is configured to perform an exhaust on the local high-point pipeline according to the exhaust signal until the total gas content rate in the important plant water system is lower than or equal to the preset threshold.

[0043] Preferably, the device further includes a state acquisition unit, a control unit, and a water conveyance execution device. The state acquisition unit is configured to acquire the working state of the important plant water system, and the working state of the important plant water system is an operating state or a shutdown state; the control unit is electrically connected to the state acquisition unit and is configured to judge whether to execute a first water conveyance step or a second water conveyance step on the important plant water system according to the working state of the important plant water system: when the working state of the important plant water system is the operating state, a first signal is sent; when the working state of the important plant water system is the shutdown state, a second signal is sent. The water conveyance execution device is electrically connected to the control unit and is configured to execute the first water conveyance step when receiving the first signal, or execute the second water conveyance step when receiving the second signal.

[0044] Preferably, the water conveyance execution device is connected to the main pipe of the important plant water system. The water conveyance execution device includes a suction culvert pipeline, a first pipeline, and a second pipeline. A suction culvert valve is provided on the suction culvert pipeline; one end of the first pipeline is communicated with the suction culvert pipeline, and the other end is communicated with the main pipe. One end of the second pipeline is communicated with the suction culvert pipeline, and the other end is communicated with the main pipe. The first pipeline and the second pipeline are arranged in parallel; a first valve, a gas-water separation device, a water seal liquid accumulation tank, and a second valve are sequentially provided on the first pipeline. A third valve is provided on the second pipeline; the suction culvert valve, the first valve, the second valve, and the third valve are electrically connected to the control unit and are used to execute the first water conveyance step when receiving a first signal: the suction culvert valve, the first valve, and the second valve are opened, and the third valve is closed to divert the cooling water input into the important plant water system to obtain a first part of cooling water and a second part of cooling water. Among them, the first part of cooling water directly enters the important plant water system through the second pipeline, and the second part of cooling water enters the first pipeline. The gas-water separation device is used to perform gas-liquid separation on the second part of cooling water to obtain preliminarily degassed water, and the water seal liquid accumulation tank is used to store the preliminarily degassed water; the suction culvert valve, the first valve, the second valve, and the third valve are used to execute the second water conveyance step when receiving a second signal: the third valve is opened, and the suction culvert valve, the first valve, and the second valve are controlled to be closed to input the preliminarily degassed water in the water seal liquid accumulation tank into the important plant water system.

[0045] Preferably, the device further includes an ultrasonic detector, which is installed at the local high-point pipeline and is used to detect the gas accumulation volume in the local high-point pipeline, that is, the local gas accumulation gas volume. The ultrasonic detector is electrically connected to the parameter acquisition unit and is used to upload the local gas accumulation gas volume to the parameter acquisition unit.

[0046] According to the embodiment of the third aspect of the present invention, an important plant water system for a nuclear power plant is provided, including: a main pipe and the above-mentioned gas content adjustment device. The main pipe has a local high-point pipeline, and the gas content adjustment device is connected to the local height pipeline and is used to perform an exhaust operation on the local high-point pipeline in the important plant water system.

[0047] Preferably, the system further includes a trap and a heat exchanger that are sequentially connected to the main pipe; the local high point pipeline includes a first local high point pipeline and a second local high point pipeline. The first local high point pipeline is located between the trap and the heat exchanger, and the second local high point pipeline is located downstream of the heat exchanger. The gas content regulating device includes: an exhaust device, and the exhaust device includes a first exhaust unit and a second exhaust unit. The first exhaust unit is connected to the first local high point pipeline for exhausting the first local high point pipeline, and the second exhaust unit is connected to the second local high point pipeline for exhausting the second local high point pipeline.

[0048] In the gas content regulating method of the present invention, by detecting the gas accumulation amount in the local high point pipeline of the important plant water system, the gas precipitation rate in the water can be calculated. Then, based on the gas precipitation rate in the water, the total gas content rate in the important plant water system is further calculated. Since the local high point pipeline is the most likely position for gas accumulation, the total gas content rate calculated based on the detection result of this pipeline can more accurately reflect the actual total gas content rate in the important plant water system. Moreover, by calculating the gas content rate in the important plant water system to determine whether the gas content rate exceeds a preset threshold, and when the total gas content rate exceeds the preset threshold, an exhaust operation is performed on the local high point pipeline in the important plant water system. Performing the exhaust operation on the local high point pipeline in the water system based on the total gas content rate has the advantage that the local high point pipeline is the position where gas accumulation is most likely to occur. By performing the exhaust operation on the local high point pipeline, the accumulated gas in the important plant water system of the nuclear power plant can be well discharged and reduced. Moreover, there is no need to continuously exhaust the local high point pipeline, as long as the total gas content rate is lower than the preset threshold, which can ensure a lower gas content in the system while avoiding excessive resource consumption.

[0049] Therefore, the present gas content regulating method can effectively reduce the accumulated gas in the important plant water system. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 is a schematic structural diagram of a gas content regulating device in some embodiments of the present invention;

[0051] Figure 2 is a schematic flowchart of a gas content regulating method in some embodiments of the present invention;

[0052] Figure 3 is a schematic structural diagram of a water conveyance execution device in some embodiments of the present invention.

[0053] In the figure: 1 - Absorbent culvert pipe, 2 - Water pump (important plant water pump), 3 - Check valve, 4 - Shellfish trap, 5 - Plate heat exchanger, 6 - Receiving tank, 7 - Drainage trough, 8 - Liquid accumulation device, 9 - First exhaust unit, 10 - Second exhaust unit, 11 - Gas-liquid separation device, 12 - Vacuum pump, 13 - Exhaust pipe, 14 - Water seal liquid accumulation tank, 15 - Liquid accumulation pipe, 16 - Absorbent culvert valve, 17 - First valve, 18 - Second valve, 19 - Third valve, 20 - Vacuum pipe, 21 - Water conveyance execution device, 22 - First pipe, 23 - Second pipe. Detailed implementation manners

[0054] The following will clearly and completely describe the technical solutions in the present invention with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts belong to the scope of the present invention.

[0055] In the description of the present invention, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0056] In the description of the present invention, each unit and module involved may correspond to only one entity structure, or may be composed of multiple entity structures. Alternatively, multiple units and modules may also be integrated into one entity structure; the units and modules involved may be implemented in software or in hardware. For example, the units and modules may be located in the processor.

[0057] In the description of the present invention, without conflict, the functions and steps marked in the flowcharts and block diagrams of the present invention may occur in an order different from that marked in the accompanying drawings.

[0058] First of all, it should be noted that the essential service water system, as a nuclear safety class system of a nuclear power plant, its function is to transfer the heat load collected by the component cooling water system to the ultimate heat sink - seawater. The technological process of the essential service water system is as follows: Water is taken after filtration by the rotary screen of the circulating water filtration system located in the combined pump house, and cooling water is provided to the plate heat exchanger located in the nuclear island building through the essential service water intake gallery. The drained water is discharged into the essential service water drainage pipeline through the overflow well of the essential service water system outside the nuclear island building, then converges to the siphon well, and finally discharges into the sea. The essential service water system of the nuclear island is an important safety system because, whether under normal operating conditions or accident conditions of the power station, this system takes out the heat transferred by the component cooling water system. And some of the equipment cooled by the component cooling water system is related to the safety system. For example, the heat exchanger of the containment spray system is one of the users of the component cooling water system. Therefore, the safety of the essential service water system is of great significance to the safe and stable operation of the nuclear power plant.

[0059] According to the feedback from a domestic second-generation improved nuclear power plant, during long-term pump shutdown of the essential service water system, pressure fluctuations will occur in the main pipe. Through investigation, maintenance, and small-scale reduced-scale tests, it is found that the internal leakage of the check valve at the outlet of the essential service water pump causes reverse siphoning in the system, which in turn triggers a flow break cavity. The associated pressure wave reflection of the check valve is the direct cause of the continuous pressure fluctuation in the system, and the gas-liquid two-phase flow formed by the air accumulation in the system itself and the air precipitation from seawater is an important cause of the pressure fluctuation in the power plant main pipe.

[0060] The internal leakage of the check valve can be solved by engineering means such as replacement. For example, the existing sealing detection device and method for the butterfly check valve of the essential service water system in nuclear power plants. This device detects the assembly quality and sealing performance of the butterfly check valve of the essential service water system in nuclear power plants, thus avoiding repeated valve maintenance from affecting the safe operation of the nuclear power plant units. Another example is the existing flushing system and method for cleaning local siltation in nuclear power plants. Using this flushing system can not only improve the operating safety of the essential service water system, but also increase the utilization rate of fresh water, save water, and effectively clean local siltation in nuclear power plants. Another example is the existing design method and device for the pump and pipeline parameters of the essential service water system in nuclear power plants. Based on personalized parameters such as different site conditions and design requirements, it helps designers to carry out intelligent customized design of the essential service water system, and based on cost optimization, an optimal economic plan is obtained on the premise of ensuring water intake safety.

[0061] However, there is currently no feasible means to solve the problem of air accumulation in the essential service water system of nuclear power plants.

[0062] Analyzing from the design of the important plant water system, when the pump or check valve is repaired, the air in the pipe section between the check valve and the outlet isolation valve of the pump and the local high points of the system cannot be discharged, and there is no automatic air exhaust device designed on the important plant water system pipeline, resulting in the important plant water pump running with air, which is prone to water hammer problems. This is a common problem.

[0063] Embodiment 1

[0064] Please refer to Figure 1 and Figure 2 , the present invention discloses a gas content adjustment method for adjusting the gas content of the important plant water system, including the following steps:

[0065] Obtain the overall parameters of the important plant water system and the gas accumulation detection parameters of the pipeline at the local high points of the important plant water system.

[0066] According to the gas accumulation detection parameters of the pipeline at the local high points, obtain the gas precipitation rate in the water.

[0067] According to the overall parameters of the important plant water system and the gas precipitation rate in the water, obtain the total gas content rate in the important plant water system.

[0068] According to the total gas content rate in the important plant water system, perform an exhaust operation on the pipeline at the local high points in the important plant water system.

[0069] It should be noted that the pipeline at the local high points refers to the part of the pipeline in the pipeline system that has a bending structure due to the pipeline layout, such as Figure 1 the pipeline between the shellfish trap 4 and the heat exchanger in

[0070] and the pipeline downstream of the heat exchanger. Due to the bending structure of this kind of pipeline, it is higher than the adjacent pipeline parts. When gas precipitates in the water body, gas accumulation is likely to occur in these parts.

[0071] By calculating the gas content rate in the important component cooling water system to determine whether the gas content rate exceeds a preset threshold, and when the total gas content rate exceeds the preset threshold, an exhaust operation is performed on the pipeline at the local high point in the important component cooling water system. Performing the exhaust operation on the pipeline at the local high point in the important component cooling water system based on the total gas content rate has the advantage that the pipeline at the local high point is the position where gas accumulation is most likely to occur. By performing the exhaust operation on the pipeline at the local high point, the accumulated gas in the important component cooling water system of the nuclear power plant can be well discharged and reduced. Moreover, there is no need to continuously exhaust the pipeline at the local high point, as long as the total gas content rate is made lower than the preset threshold, which can ensure a lower gas content in the system while avoiding excessive resource consumption.

[0072] The exhaust operation can be achieved by using existing equipment such as exhaust pumps, air extraction pumps, vacuum pumps 12, etc.

[0073] This method is applicable to the important component cooling water system of the nuclear island of a nuclear power plant. As Figure 1 shown, first, the application scenario of the important component cooling water system of the nuclear power plant is described:

[0074] The important component cooling water system includes a main pipe, a water pump 2, a shellfish trap 4, a heat exchanger, a receiving pool 6, and a drain tank 7. The main pipe is sequentially connected to the water pump 2, the shellfish trap 4, the cold-side pipeline of the heat exchanger, the receiving pool 6, and the drain tank 7. Water is sucked through the water pump 2 and the cooling water is introduced into the main pipe. The important component cooling water system usually uses seawater as the cooling water, and natural dissolved gases are usually contained in the seawater. After entering the main pipe, this part of the gas precipitates, resulting in accumulated gas in the main pipe, and then forming a gas-liquid two-phase flow. When the pump stops, the gas-liquid two-phase flow formed by the accumulated gas in the system itself and the air precipitated from the seawater will cause pressure fluctuations in the main pipe, and then cause a water hammer effect. The water hammer effect is likely to damage the water pump 2, and cause pipeline fatigue, cracks, and even rupture, thus triggering leakage or pipe burst accidents.

[0075] As Figure 1 shown, the important component cooling water system is installed in the plant building of the nuclear power plant. The plant building of the nuclear power plant includes a deaeration building, a combined pump house, an important component cooling water inlet pipe warehouse, a nuclear island building, and an important component cooling water drainage structure. Among them, the deaeration building, the combined pump house, the important component cooling water inlet pipe warehouse, the nuclear island building, and the important component cooling water drainage structure are arranged in sequence. Among them, the combined pump house is used to install the water pump 2 and the check valve 3, the important component cooling water inlet pipe warehouse is used to accommodate part of the main pipe, and the nuclear island building is used to accommodate the shellfish trap 4 and the heat exchanger. The important component cooling water drainage structure includes a receiving pool 6 and a drain tank 7, which are used to receive the cooled cooling water (seawater).

[0076] This method is achieved through an air content regulating device. Specifically, the air content regulating device includes an exhaust device and a water conveyance execution device 21. Among them, the exhaust device includes a first exhaust unit 9 and a second exhaust unit 10, and both the first exhaust unit 9 and the second exhaust unit 10 can adopt existing air pumps. The first exhaust unit 9 and the second exhaust unit 10 are located in the nuclear island plant building. The first exhaust unit 9 is connected to the first local high point pipeline, that is, the pipeline between the shellfish trap 4 and the heat exchanger as shown in Figure 1 in the pipeline between the shellfish trap 4 and the heat exchanger, and the second exhaust unit 10 is connected to the second local high point pipeline, and the second local high point pipeline is located in the pipeline downstream of the heat exchanger.

[0077] It can be seen that in this method, by exhausting the first local high point pipeline and the second local high point pipeline in the important component cooling water system, the accumulated air in the important component cooling water system of the nuclear power plant can be better discharged and reduced.

[0078] In summary, this method can effectively reduce the accumulated air in the important component cooling water system.

[0079] In some embodiments, the air accumulation detection parameters of the local high point pipeline include: local accumulated air volume, local gas-containing volume;

[0080] According to the air accumulation detection parameters of the local high point pipeline, the gas precipitation rate in water is obtained. Specifically:

[0081] According to the local accumulated air volume and the local gas-containing volume, the gas precipitation rate in water is calculated.

[0082] It should be noted that the calculation processes in this embodiment can all be implemented through existing computer programs. The local accumulated air volume (i.e., the air accumulation volume in the local high point pipeline) can be detected by an ultrasonic detector installed in the local high point pipeline and automatically uploaded to the computer program.

[0083] The local gas-containing volume can be manually measured by the staff and manually uploaded to the computer program. The calculation formula for the local gas-containing volume is as follows:

[0084]

[0085] For example, taking the important component cooling water system as an example, the total volume of the pipe section refers to the total volume of the pipe section from the inlet of the main pipe to the inlet pipe of the heat exchanger. In an environment where the temperature and water body are determined (such as seawater), the oxygen content ratio in the water body and the proportion of oxygen in the gases in the water body can be obtained by referring to existing literature.

[0086] For example: By referring to relevant literature, it can be known that at 20 °C, 3 liters of oxygen can be dissolved in 100 liters of water. The share of dissolved oxygen in seawater in the total dissolved gases is shown in Table 1 below:

[0087] Table 1. Table of Dissolved Fractions of Various Gases

[0088] Gas <![CDATA[N2]]> <![CDATA[O2]]> Ar <![CDATA[CO2]]> Ne He Kr Xe <![CDATA[f air > 0.780 0.209 0.009 0.0003 1.82E-05 5.2E-07 1.1E-08 9E-09 <![CDATA[f SW > 0.626 0.343 0.016 9.7E-07 2.3E-06 3.8E-07 5.4E-07 5.4E-07

[0089] Specifically, the fractions in Table 1 are the fractions of different gases in each cubic centimeter of air (NTP) in 1 kg of saturated seawater (S = 35, t = 20 °C).

[0090] Among them, f air refers to the proportion fraction of various gases in the air, and f SW refers to the proportion fraction of various gases in the seawater.

[0091] It can be learned from the above table that the oxygen content ratio in water at 20 °C is about 3%, and the proportion of oxygen in the gases in the water body is 34.30%.

[0092] In this embodiment, by combining an ultrasonic detector with numerical calculation, the gas evolution rate in water can be calculated more accurately.

[0093] Furthermore, calculating the gas evolution rate in water based on the local gas accumulation volume and the local gas-containing volume further includes:

[0094] Establishing a first calculation equation based on the local gas accumulation volume and the local gas-containing volume;

[0095] The first calculation equation is:[[]]

[0096]

[0097] Calculating the gas evolution rate in water according to the first calculation equation.

[0098] It is easy to understand that the gas evolution rate in water refers to the ratio of the local gas accumulation volume (i.e., the gas accumulation volume in the local high-point pipeline) to the local gas-containing volume (the total gas content in the water body in the local high-point pipeline). The local high-point pipeline is the position where gas accumulation is most likely to occur. Therefore, calculating the gas evolution rate in water through the gas accumulation volume here can more accurately reflect the actual situation.

[0099] In some embodiments, the overall parameters of the important plant water system include: the overall volume of the important plant water system and the total gas-containing volume;

[0100] According to the overall volume parameter of the important plant water system and the gas evolution rate in water, the total gas content rate in the important plant water system is obtained, specifically:[[]]

[0101] Calculating the gas content rate in the important plant water system according to the overall volume of the important plant water system, the total gas-containing volume, and the gas evolution rate in water.

[0102] It should be noted that the total gas volume can be calculated according to the following calculation formula:

[0103]

[0104] Furthermore, according to the total volume of the important plant service water system, the total gas volume, and the gas evolution rate in water, the gas content rate in the important plant service water system is calculated, and it also includes:

[0105] Based on the total volume of the important plant service water system, the total gas volume, and the gas evolution rate in water, a second calculation equation is established;

[0106] The second calculation equation is:

[0107]

[0108] According to the second calculation equation, the gas content rate in the important plant service water system is calculated.

[0109] In this embodiment, through (total gas volume × gas evolution rate in water), the total gas volume in the important plant service water system can be obtained. The gas evolution rate in water is calculated based on the gas volume in the local high-point pipeline, which can accurately reflect the total gas volume in the entire water-using equipment. By calculating the total gas content rate with (total gas volume × gas evolution rate in water) and the total volume of the important plant service water system, and exhausting the gas in the local high-point pipeline according to the total gas content rate, the gas accumulation in the important plant service water system can be discharged more accurately and effectively.

[0110] Moreover, compared with continuously exhausting the gas in the local high-point pipeline, judging whether to perform the gas exhaust operation on the local high-point pipeline through the total gas content rate can ensure a lower gas content in the system while avoiding excessive resource consumption.

[0111] Please refer to Figure 2 , in some embodiments, according to the total gas content rate in the important plant service water system, the gas exhaust operation on the local high-point pipeline in the important plant service water system is performed, which specifically includes:

[0112] Judge whether the total gas content rate in the important plant service water system is lower than or equal to the preset threshold:

[0113] If so, it is determined that the total gas content rate in the important plant service water system meets the requirements;

[0114] If not, the gas in the local high-point pipeline is exhausted until the total gas content rate in the important plant service water system is lower than or equal to the preset threshold.

[0115] Among them, the preset threshold is 0.2% - 0.5%. Exemplarily, it can be 0.2%, 0.3%, 0.4%, 0.5%. Preferably, it is 0.2%. When the total gas content rate of the important plant water system calculated through the above steps is less than or equal to 0.2%, it is determined that the system is stable, and at this time, there is no need to perform the exhaust operation. When the total gas content rate is higher than 0.2%, it is determined that the gas content in the system is too high, and the accumulated gas precipitated in the water will cause fluctuations in the main pipe, which will further cause pipeline fatigue, cracks or even rupture. At this time, exhaust is required until the total gas content rate drops below 0.2% again.

[0116] In this embodiment, through the comparison between the total gas content rate and the preset threshold, the exhaust operation is carried out to reduce the total gas content rate below the preset threshold. The total gas content rate below 0.2% can effectively reduce the risk caused by gas accumulation in the pipeline system. Moreover, the exhaust operation is realized through exhaust equipment such as a suction pump. Continuously performing the exhaust operation requires a large amount of energy. The dynamic exhaust adjustment method in this embodiment can avoid consuming too many resources while ensuring a low gas content in the system compared with continuously exhausting the local high-point pipeline.

[0117] In some embodiments, before performing the exhaust operation on the local high-point pipeline in the important plant water system according to the total gas content rate in the important plant water system, it further includes:

[0118] Obtain the working state of the important plant water system. The working state of the important plant water system is the running state or the shutdown state;

[0119] According to the working state of the important plant water system, judge to execute the first water conveyance step or the second water conveyance step for the important plant water system:

[0120] When the working state of the important plant water system is the running state, execute the first water conveyance step;

[0121] When the working state of the important plant water system is the shutdown state, execute the second water conveyance step.

[0122] Specifically, the first water conveyance step includes: diverting the cooling water input into the important plant water system to obtain the first part of the cooling water and the second part of the cooling water. Among them, the first part of the cooling water directly enters the important plant water system, and the second part of the cooling water is subjected to gas-liquid separation to obtain the preliminarily degassed water, and the preliminarily degassed water is stored, and the first water conveyance step ends.

[0123] The second water conveyance step includes: inputting the preliminarily degassed water into the important plant water system, and the second water conveyance step ends.

[0124] The above-mentioned gas content regulating device includes a state acquisition unit, a control unit, and a water conveyance execution device 21. The water conveyance execution device 21 is used to execute the first water conveyance step and the second water conveyance step. The water conveyance execution device 21 is accommodated in the deaeration workshop. The control unit is used to judge whether to execute the first water conveyance step or the second water conveyance step on the important plant water system according to the working state of the important plant water system acquired by the state acquisition unit: when the working state of the important plant water system is the operating state, a first signal is sent; when the working state of the important plant water system is the shutdown state, a second signal is sent. The water conveyance execution device 21 is electrically connected to the control unit and is used to execute the first water conveyance step when receiving the first signal, or execute the second water conveyance step when receiving the second signal.

[0125] Specifically, as Figure 1 shown, the water conveyance execution device 21 includes a suction culvert pipe 1, a first pipe 22, and a second pipe 23. A suction culvert valve 16 is provided on the suction culvert pipe 1. One end of the first pipe 22 is communicated with the suction culvert pipe 1, and the other end is communicated with the main pipe. One end of the second pipe 23 is communicated with the suction culvert pipe 1, and the other end is communicated with the main pipe. The first pipe 22 and the second pipe 23 are arranged in parallel.

[0126] A first valve 17, a gas-liquid separation device 11, a water seal liquid accumulation tank 14, and a second valve 18 are successively arranged on the first pipe 22. A third valve 19 is provided on the second pipe 23.

[0127] The suction culvert valve 16, the first valve 17, the second valve 18, and the third valve 19 are electrically connected to the control unit and are used to execute the first water conveyance step when receiving the first signal:

[0128] The suction culvert valve 16, the first valve 17, and the second valve 18 are opened, and the third valve 19 is closed to divert the cooling water input into the important plant water system to obtain a first part of cooling water and a second part of cooling water. Among them, the first part of cooling water directly enters the important plant water system through the second pipe 23, and the second part of cooling water enters the first pipe 22. The gas-liquid separation device 11 is used to perform gas-liquid separation on the second part of cooling water to obtain preliminarily deaerated water, and the water seal liquid accumulation tank 14 is used to store the preliminarily deaerated water.

[0129] The suction culvert valve 16, the first valve 17, the second valve 18, and the third valve 19 are used to execute the second water conveyance step when receiving the second signal: the third valve 19 is opened, and the control suction culvert valve 16, the first valve 17, and the second valve 18 are closed to input the preliminarily deaerated water in the water seal liquid accumulation tank 14 into the important plant water system.

[0130] It should be noted that the working state of the important service water system is the running state or the shutdown state. When the water pump 2 in the important service water system is shut down, the important service water system is in the shutdown state; when the water pump 2 in the important service water system is started, the important service water system is in the running state. The staff can control the start or stop of the water pump 2 through the operation console.

[0131] Exemplarily, when the staff sends a start signal for the water pump 2 through the operation console, the state acquisition unit determines that the important service water system is about to switch to the running state according to the start signal of the water pump 2. At this time, the control unit first controls the water conveyance execution device 21 to execute the first water conveyance step, and then the water pump 2 is officially started. In other words, before the water pump 2 is started, the first adjustment action of the valve is completed, that is, the suction culvert valve 16, the first valve 17 and the second valve 18 are opened, and the third valve 19 is closed.

[0132] Exemplarily, when the staff sends a shutdown signal for the water pump 2 through the operation console, the state acquisition unit determines that the important service water system is about to switch to the shutdown state according to the shutdown signal of the water pump 2. At this time, the control unit first controls the water conveyance device to execute the second water conveyance step, and then the water pump 2 is officially shut down. In other words, before the water pump 2 stops, the second adjustment action of the valve is completed, that is, the third valve 19 is opened, and the suction culvert valve 16, the first valve 17 and the second valve 18 are closed.

[0133] In this embodiment, when the important service water system is in the running state, by opening the suction culvert valve 16, the first valve 17 and the second valve 18 and closing the third valve 19, part of the water is subjected to gas-liquid separation through the gas-water separation device 11 to obtain preliminarily degassed water, and the preliminarily degassed water enters the water seal liquid accumulation tank 14 for storage; the other part of the influent directly enters the important service water system. When the important service water system is in the shutdown state, by opening the third valve 19 and closing the suction culvert valve 16, the first valve 17 and the second valve 18, the introduction of water flow from the outside is stopped, and the preliminarily degassed water in the water seal liquid accumulation tank 14 enters the important service water system.

[0134] Exemplarily, when the important service water system is running normally, the third valve 19 is closed by the water conveyance execution device 21, so that the water seal liquid accumulation tank 14 is isolated from the pipeline of the important service water system. Only when the pump is shut down, the third valve 19 is opened to connect the water seal liquid accumulation tank 14 with the important service water system to supplement liquid to the system and relieve the gas accumulation and water hammer effect caused by leakage.

[0135] In summary, the present method can discharge the gas in the important service water system during the operation process of the important service water system and prevent gas from remaining in the pipeline. Even if a water hammer occurs, due to the absence of gas, the damage to the pipeline and the system is reduced when the water hammer occurs.

[0136] Taking an important plant of a nuclear power plant as an example, the implementation process of the gas content regulation method will be described in combination with the specific structure of the gas content regulation device.

[0137] The gas content regulation method in this embodiment, that is, a method for reducing the gas content in the important service water system of a nuclear power plant, is implemented by using the following gas content regulation device, that is, a device for reducing the gas content in the important service water system of a nuclear power plant.

[0138] As Figure 1 and Figure 3 shown, the gas content regulation device includes a water conveyance execution device 21 and an exhaust device.

[0139] Among them, the exhaust device includes an automatic exhaust device at 4 places of the shellfish trap (i.e., the above-mentioned first exhaust unit 9) and an automatic exhaust device at 5 places of the plate heat exchanger (i.e., the above-mentioned second exhaust unit 10). As Figure 3 shown, the water conveyance execution device 21 includes a liquid accumulation device 8, a gas-liquid separation device 11, a vacuum pump 12, a water seal liquid accumulation tank 14, a suction culvert pipe 1, a first pipe 22 and a second pipe 23, an exhaust pipe 13, and a vacuum pipe 20. As Figure 1 shown, the suction culvert pipe 1 is connected to the gas-liquid separation device 11, the liquid accumulation device 8, the water seal liquid accumulation tank 14, and the main pipe of the important service water system in sequence through the first pipe 22. The liquid accumulation device 8 is located below the gas-liquid separation device 11 and is connected to the gas-liquid separation device 11. The gas-liquid separation device 11 adopts an existing gas-liquid separator, for example: a gas-liquid separator with the model ZCQF. The vacuum pump 12 is connected to the gas-liquid separation device 11 through the vacuum pipe 20, and is used to extract the gas in the gas-liquid separation device 11 and discharge these gases through the exhaust pipe 13. The first pipe 22 includes a liquid accumulation pipe 15, and the liquid accumulation pipe 15 is located between the liquid accumulation device 8 and the water seal liquid accumulation tank 14, with one end connected to the liquid accumulation device 8 and the other end connected to the water seal liquid accumulation tank 14, for the liquid accumulated in the liquid accumulation device 8 to enter the water seal liquid accumulation tank 14.

[0140] Continuing as Figure 3 shown, one end of the second pipe 23 is connected to the suction culvert pipe 1, and the other end is connected to the main pipe. The first pipe 22 and the second pipe 23 are arranged in parallel.

[0141] Furthermore, the automatic exhaust device at 4 places of the shellfish trap is arranged on the local high point pipe section of the shellfish trap. The automatic exhaust device at 5 places of the plate heat exchanger is arranged on the local high point pipe section of the plate heat exchanger. The gas-liquid separation device 11 is arranged above the liquid accumulation device 8. One end of the vacuum pipe 20 is connected to the gas-liquid separation device 11, and the other end is connected to the vacuum pump 12. The outlet section of the vacuum pump 12 is connected to the exhaust pipe 13. One end of the liquid accumulation pipe 15 is connected to the liquid accumulation device 8, and the other end is connected to the water seal liquid accumulation tank 14. The gas-liquid separation device 11 is connected to the suction culvert pipe 1.

[0142] As Figure 3 shown, the water conveyance execution device 21 further includes a suction culvert valve 16, Valve I (i.e., the aforementioned first valve 17), Valve II (i.e., the aforementioned second valve 18), and Valve III (i.e., the aforementioned third valve 19). The suction culvert valve 16 is arranged on the suction culvert pipeline 1 and is used to control the opening and closing of the suction culvert. Valve I (the first valve 17) and Valve III (the third valve 19) are installed on the first pipeline 22. Among them, Valve I is located between the first set connection port and the gas-water separation device 11. The first set connection port is the connection port of the second pipeline 23 and the suction culvert, that is, Valve I is located downstream of the first set connection port and upstream of the inlet of the gas-water separation device 11. Valve III is located between the outlet of the water seal liquid accumulation tank 14 and the second set connection port. The second set connection port is the connection port of the second pipeline 23 and the main pipe, that is, Valve III is located downstream of the outlet of the water seal liquid accumulation tank 14 and upstream of the second set connection port.

[0143] An air removal plant is provided before the combined pump house, and a device system for reducing the gas content in the important service water system of the nuclear power plant (that is, the water conveyance execution device 21 of this gas content adjustment device is arranged in the air removal plant) is arranged in the air removal plant. The automatic exhaust devices at the shellfish trap 4 and the plate heat exchanger 5 are both arranged on the local high point pipe sections of the system pipeline. The gas-water separation device 11 is arranged above the liquid accumulation device 8. The gas-water separation device 11 is communicated with the suction culvert pipeline 1. The device for reducing the gas content in the important service water system of the nuclear power plant adopted in this embodiment can discharge the gas in the system during the operation of the important service water system, prevent gas from existing in the pipeline, and reduce the damage to the pipeline and the system when water hammer occurs. After the important service water system is shut down, ensure that there is a low gas content in the system to avoid problems such as the pressure fluctuation of the main pipe during shutdown.

[0144] This device for reducing the gas content in the important service water system of the nuclear power plant must ensure the coordination of the liquid discharge volume and the liquid suction volume. The volume of the water seal liquid accumulation tank 14 needs to be greater than the volume of the important service water system. A water seal is arranged at the outlet of the liquid accumulation pipeline 15 arranged on the water seal liquid accumulation tank 14 to prevent air from entering. The height difference range between the liquid accumulation device 8 and the water seal liquid accumulation tank 14 is taken as 11 - 15m. The vacuum pump 12 is arranged on the ground at least 11m high from the water seal liquid accumulation tank 14. Ultrasonic detectors are arranged in both the automatic exhaust devices at the shellfish trap 4 and the plate heat exchanger 5 to detect the gas accumulation volume in the local high point pipeline.

[0145] As Figure 1 and Figure 2 shown, a method for reducing the gas content in the important service water system of the nuclear power plant specifically includes:

[0146] 1. When the important service water system is operating

[0147] Step 1) A part of the liquid flow enters the degassing plant from the water absorption culvert. At this time, the valve 16 of the water absorption culvert is opened, valves I and II are opened, and valve III is closed; a part enters the combined pump house under the action of the important service water pump 2, enters the nuclear island building via the important service water intake pipe gallery, and finally is discharged from the important service water drainage structure.

[0148] Step 2) Inside the degassing plant, the liquid flow is first pumped into the gas-water separator by the vacuum pump 12. The air is drawn away by the upper vacuum pipe 20 and discharged through the exhaust pipe 13. The filtrate enters the liquid accumulation device 8 and automatically flows into the water seal liquid accumulation tank 14 from the liquid accumulation pipe 15 under the action of gravity until the liquid level height set in the water seal liquid accumulation tank 14 is reached.

[0149] Step 3) Inside the nuclear island building, the ultrasonic detectors set in the automatic exhaust device at the shellfish trap 4 and the automatic exhaust device at the plate heat exchanger 5 detect the gas volume in the local high-point pipeline. First, calculate the gas evolution rate in seawater according to the detection results; then calculate the total gas content in the system pipeline according to the gas volume in seawater and the gas evolution rate in seawater obtained by calculation; finally, judge the total gas content in the system pipeline obtained by calculation. If the total gas content in the system pipeline is greater than 0.2%, start the automatic exhaust device at the shellfish trap 4 and the automatic exhaust device at the plate heat exchanger 5 to exhaust the system. If the total gas content in the system pipeline is less than or equal to 0.2%, no exhaust is required. After exhaust, perform gas volume detection again. If the total gas content in the system pipeline is less than or equal to 0.2%, the system is in a stable state at this time, otherwise it is in an unstable state and still requires exhaust.

[0150] 2. When the important service water system is shut down

[0151] At this time, the valve 16, valves I and II of the water absorption culvert are closed, and valve III is opened; before the important service water system is shut down, pump the low gas content liquid flow in the water seal liquid accumulation tank 14 until the entire pipeline of the important service water system is filled, and repeat step 3) during the operation of the important service water system until the system is stable.

[0152] Specific embodiment: A small amount of air in the pipeline system will have a great impact on the water hammer wave propagation speed. Due to system air intake and the separation of gas dissolved in seawater, etc., air will be retained in the important service water system.

[0153] Table 2. Pipeline parameters of the important service water system

[0154]

[0155]

[0156] It can be seen from Table 2 that the total volume of the system pipeline is 169.4 m 3 .

[0157] Table 3. Example Table of Related Parameters of Gas Content in Seawater The calculation process of the gas volume in seawater is shown in the following table:

[0158]

[0159]

[0160] Table 3 shows the calculation process of the total gas volume in seawater.

[0161] According to the system elevation drawing, determine the volume of the pipe section from the main pipe inlet to the heat exchanger inlet. In this specific embodiment, the power plant actually uses ultrasonic waves to check whether there are air cavities in the pipelines of the important plant water system. The inspection results show that there is an air cavity in the horizontal pipeline at the shellfish trap 4 (local high point), and the volume of the air cavity accounts for about 20% of the volume of the horizontal pipe section, proving that the main pipe of the important plant water system contains air after maintenance.

[0162] Obtain the gas volume of the horizontal pipe section at the shellfish trap 4 and calculate the gas precipitation rate in seawater, as shown in Table 4 below:

[0163] Table 4. Example Table of Seawater Gas Precipitation Rate

[0164]

[0165]

[0166]

[0167] According to the gas volume in seawater and the gas precipitation rate in seawater obtained from the above calculations, calculate the total gas content of the system pipeline, as shown in Table 5 below:

[0168] Table 5. Example Table of Total Gas Content Rate of the Important Plant Water System Pipeline

[0169] Item Specification Unit Value Total system volume / <![CDATA[m 3 > 169.4 Gas evolution rate in seawater / ％ 8.82 Volume of evolved gas in seawater / <![CDATA[m 3 > 1.31 Total gas content rate / ％ 0.77

[0170]

[0171] It can be seen that the total gas content rate calculated in the above example is 0.77%, which is higher than the preset threshold (taking the preset threshold as 0.2% as an example). At this time, it is necessary to start the exhaust equipment (the first exhaust unit 9 and the second exhaust unit 10), and repeat the above calculations until the calculated total gas content rate is lower than or equal to the preset threshold, then stop running the preset threshold.

[0172] Embodiment 2

[0173] Please refer toFigure 1 Moreover, the present invention also discloses an air content adjusting device for adjusting the air content in an important plant water system. The device includes: a parameter acquisition unit, a first calculation unit, a second calculation unit, and an adjustment unit.

[0174] Among them, the parameter acquisition unit is used to acquire the overall parameters of the important plant water system and the air accumulation detection parameters of the local high-point pipeline of the important plant water system. The first calculation unit is electrically connected to the parameter acquisition unit and is used to obtain the gas precipitation rate in water according to the air accumulation detection parameters of the local high-point pipeline. The second calculation unit is electrically connected to the parameter acquisition unit and the first calculation unit respectively, and is used to obtain the total air content rate in the important plant water system according to the overall parameters of the important plant water system and the gas precipitation rate in water. The adjustment unit is electrically connected to the second calculation unit and is used to perform an exhaust operation on the local high-point pipeline in the important plant water system according to the total air content rate in the important plant water system.

[0175] It should be noted that the parameter acquisition unit can be a software module installed on a computer device. After the staff obtains the overall parameters of the important plant water system and the air accumulation detection parameters of the local high-point pipeline of the important plant water system, they can manually upload them to this module. These data can also be pre-stored in a database and can be called through the parameter acquisition unit when needed.

[0176] The first calculation unit and the second calculation unit can also be software modules installed on a computer device, and calculate the gas precipitation rate in water and the total air content rate through a preset program.

[0177] The device calculates the air content rate in the important plant water system (i.e., the aforementioned important plant water system) to determine whether the air content rate exceeds a preset threshold, and when the total air content rate exceeds the preset threshold, the adjustment unit performs an exhaust operation on the local high-point pipeline in the important plant water system. Performing an exhaust operation on the local high-point pipeline in the important plant water system based on the total air content rate has the advantage that the local high-point pipeline is the position where gas accumulation is most likely to occur. By performing an exhaust operation on the local high-point pipeline, the accumulated gas in the important plant water system of the nuclear power plant can be well discharged and reduced. Moreover, there is no need to continuously exhaust the local high-point pipeline, as long as the total air content rate is lower than the preset threshold, which can ensure a low air content in the system while avoiding excessive consumption of resources.

[0178] Further, the adjustment unit includes a first analysis module and an exhaust device. The first analysis module is configured to determine whether the total gas content rate in the important service water system is lower than or equal to a preset threshold: if so, it is determined that the total gas content rate in the important service water system meets the requirements. If not, an exhaust signal is issued. The exhaust device is electrically connected to the analysis module and is configured to exhaust the local high-point pipeline according to the exhaust signal until the total gas content rate in the important service water system is lower than or equal to the preset threshold.

[0179] The device further includes a state acquisition unit, a control unit, and a water delivery execution device 21. The state acquisition unit is configured to acquire the working state of the important service water system, and the working state of the important service water system is an operating state or a shutdown state. The control unit is electrically connected to the state acquisition unit and is configured to determine whether to execute a first water delivery step or a second water delivery step on the important service water system according to the working state of the important service water system: when the working state of the important service water system is the operating state, a first signal is issued. When the working state of the important service water system is the shutdown state, a second signal is issued. The water delivery execution device 21 is electrically connected to the control unit and is configured to execute the first water delivery step when receiving the first signal, or execute the second water delivery step when receiving the second signal.

[0180] The water conveyance execution device 21 is connected to the main pipe of the important plant water system. The water conveyance execution device 21 includes a suction culvert pipeline 1, a first pipeline 22, and a second pipeline 23. A suction culvert valve 16 is provided on the suction culvert pipeline 1. One end of the first pipeline 22 is communicated with the suction culvert pipeline 1, and the other end is communicated with the main pipe. One end of the second pipeline 23 is communicated with the suction culvert pipeline 1, and the other end is communicated with the main pipe. The first pipeline 22 and the second pipeline 23 are arranged in parallel. A first valve 17, a gas-water separation device 11, a water seal liquid accumulation pool 14, and a second valve 18 are successively provided on the first pipeline 22. A third valve 19 is provided on the second pipeline 23. The suction culvert valve 16, the first valve 17, the second valve 18, and the third valve 19 are electrically connected to the control unit and are used to execute the first water conveyance step when receiving a first signal: the suction culvert valve 16, the first valve 17, and the second valve 18 are opened, and the third valve 19 is closed, so as to split the cooling water input into the important plant water system to obtain a first part of cooling water and a second part of cooling water. Among them, the first part of cooling water directly enters the important plant water system through the second pipeline 23, and the second part of cooling water enters the first pipeline 22. The gas-water separation device 11 is used to perform gas-liquid separation on the second part of cooling water to obtain preliminarily degassed water, and the water seal liquid accumulation pool 14 is used to store the preliminarily degassed water. The suction culvert valve 16, the first valve 17, the second valve 18, and the third valve 19 are used to execute the second water conveyance step when receiving a second signal: the third valve 19 is opened, and the suction culvert valve 16, the first valve 17, and the second valve 18 are controlled to be closed, so as to input the preliminarily degassed water in the water seal liquid accumulation pool 14 into the important plant water system.

[0181] This device further includes an ultrasonic detector, which is installed at the local high point pipeline and is used to detect the gas accumulation volume in the local high point pipeline, that is, the local accumulated gas volume. The ultrasonic detector is electrically connected to the parameter acquisition unit and is used to upload the local accumulated gas volume to the parameter acquisition unit.

[0182] The gas content adjustment device provided in this embodiment (a test device system and method for reducing the gas content in the important plant water system of a nuclear power plant) can discharge the gas in the important plant water system during operation and prevent gas from existing in the pipeline. Even if a water hammer occurs, due to the absence of gas, the damage to the pipeline and the system during the water hammer is reduced.

[0183] The gas content regulating device includes a liquid accumulation device 8, an automatic exhaust device at the shellfish trap 4, an automatic exhaust device at the plate heat exchanger 5, a gas-liquid separation device 11, a vacuum pump 12, an exhaust pipe 13, a water seal liquid accumulation tank 14, a liquid accumulation pipe 15, a water absorption culvert valve 16, Valve I, Valve II, Valve III, a vacuum pipe 20, etc. An air removal workshop is arranged before the combined pump house, and a device system for reducing the gas content in the important service water system of the nuclear power plant is arranged in the air removal workshop. The automatic exhaust device at the shellfish trap 4 is arranged at the high point of the pipe section between the water outlet of the shellfish trap 4 and the water inlet of the plate heat exchanger 5. The automatic exhaust device at the plate heat exchanger 5 is arranged at the local high point pipe section of the plate heat exchanger 5. The gas-liquid separation device 11 is arranged above the liquid accumulation device 8. One end of the vacuum pipe 20 is connected to the gas-liquid separation device 11, and the other end is connected to the vacuum pump 12. The outlet section of the vacuum pump 12 is connected to the exhaust pipe 13. One end of the liquid accumulation pipe 15 is connected to the liquid accumulation device 8, and the other end is connected to the water seal liquid accumulation tank 14. The gas-liquid separation device 11 is connected to the water absorption culvert pipe 1.

[0184] The device system for reducing the gas content in the important service water system of the nuclear power plant must ensure the coordination of the liquid discharge amount and the liquid suction amount. The volume of the water seal liquid accumulation tank 14 needs to be larger than the volume of the important service water system. A water seal is arranged at the outlet of the liquid accumulation pipe 15 arranged on the water seal liquid accumulation tank 14 to prevent air from entering. The height difference range between the liquid accumulation device 8 and the water seal liquid accumulation tank 14 is taken as 11 - 15 m, and the vacuum pump 12 is arranged on the ground at least 11 m higher than the water seal liquid accumulation tank 14. Ultrasonic detectors are arranged in both the automatic exhaust device at the shellfish trap 4 and the automatic exhaust device at the plate heat exchanger 5 to detect the gas accumulation amount in the local high point pipeline.

[0185] The corresponding gas content regulating method of this device specifically includes:

[0186] 1. When the important service water system is operating

[0187] Step 1) A part of the liquid flow enters the air removal workshop from the water absorption culvert. At this time, the water absorption culvert valve 16 is opened, Valve I and Valve II are opened, and Valve III is closed; a part enters the combined pump house under the action of the important service water pump 2, enters the nuclear island building through the important service water inlet corridor, provides cooling water for the plate heat exchanger 5, and finally is discharged from the important service water drainage structure.

[0188] Step 2) In the air removal workshop, the liquid flow is first pumped into the gas-liquid separator by the vacuum pump 12. The air is pumped away by the upper vacuum pipe 20 and discharged through the exhaust pipe 13. The filtrate enters the liquid accumulation device 8 and automatically flows into the water seal liquid accumulation tank 14 from the liquid accumulation pipe 15 under the action of gravity until the liquid level height set by the water seal liquid accumulation tank 14 is reached.

[0189] Step 3) In the nuclear island building, ultrasonic detectors installed in the automatic exhaust devices at the shellfish trap 4 and the plate heat exchanger 5 detect the gas volume in the local high-point pipelines. First, calculate the gas evolution rate in seawater based on the detection results; then, calculate the total gas content in the system pipelines according to the calculated gas volume in seawater and the gas evolution rate in seawater; finally, judge the calculated total gas content in the system pipelines. If the total gas content in the system pipelines is greater than 0.2%, start the automatic exhaust devices at the shellfish trap 4 and the plate heat exchanger 5 to exhaust the system. If the total gas content in the system pipelines is less than or equal to 0.2%, no exhaust is required. After exhaust, conduct gas volume detection again. If the total gas content in the system pipelines is less than or equal to 0.2%, the system is in a stable state at this time; otherwise, it is in an unstable state and still requires exhaust.

[0190] 2. When the important component cooling water system is shut down

[0191] At this time, the suction culvert valve 16, valve I, and valve II are closed, and valve III is opened; before the important component cooling water system is shut down, pump the low-gas-content liquid flow in the water seal sump 14 until the entire pipeline of the important component cooling water system is filled, and repeat step 3) during the operation of the important component cooling water system until the system is stable.

[0192] The beneficial effects of this device are as follows:

[0193] By adopting this device (the device system for reducing the gas content in the important component cooling water system of a nuclear power plant), the gas in the system can be discharged during the operation of the important component cooling water system, and gas in the pipeline can be prevented. Even if a water hammer occurs, due to the absence of gas, the damage to the pipeline and the system caused by the water hammer can be reduced. At the same time, after the important component cooling water system is shut down, a low gas content in the system is ensured, avoiding problems such as fluctuations in the main pipe pressure during shutdown.

[0194] Embodiment 3

[0195] Please refer to Figure 1 , the present invention also discloses an important component cooling water system of a nuclear power plant, including: a main pipe and the gas content adjustment device in Embodiment 2.

[0196] Among them, the main pipe has local high-point pipelines, and the gas content adjustment device is connected to the local high-point pipelines for exhausting the local high-point pipelines in the important component cooling water system.

[0197] Furthermore, the important component cooling water system of the nuclear power plant further includes a trap and a heat exchanger that are successively connected to the main pipe; the local high-point pipelines include a first local high-point pipeline and a second local high-point pipeline. The first local high-point pipeline is located between the trap and the heat exchanger, and the second local high-point pipeline is located downstream of the heat exchanger. The gas content regulating device includes: an exhaust device, and the exhaust device includes a first exhaust unit 9 and a second exhaust unit 10. The first exhaust unit 9 is connected to the first local high-point pipeline for exhausting the first local high-point pipeline, and the second exhaust unit 10 is connected to the second local high-point pipeline for exhausting the second local high-point pipeline.

[0198] By adopting the gas content regulating device, the important component cooling water system of the nuclear power plant can effectively reduce the accumulated gas in the important component cooling water system, thereby avoiding the occurrence of water hammer problems.

[0199] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principle of the present invention. However, the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims

1. A method for regulating gas content, used for regulating gas content in an important plant water system, characterized in that: The steps include: Obtaining the overall parameters of the important plant water system and the gas accumulation detection parameters of the local high-point pipelines of the important plant water system; According to the gas accumulation detection parameter of the local high point pipeline, the gas precipitation rate in the water is obtained; According to the overall parameters of the important plant water system and the gas release rate in the water, the total gas content in the important plant water system is obtained; According to the total gas content in the important plant water system, the local high-point pipelines in the system are vented.

2. The gas content adjustment method according to claim 1, characterized in that: The gas accumulation detection parameters of the local high-point pipeline include: local gas accumulation gas volume, local gas-containing volume; The gas precipitation rate in water is obtained according to the gas accumulation detection parameter of the local high point pipeline, specifically: The gas evolution rate in water is calculated based on the local gas accumulation volume and the local gas-containing volume.

3. The gas content adjustment method according to claim 2, characterized in that: The step of calculating the gas release rate in water according to the local gas accumulation volume and the local gas-containing volume comprises: Establishing a first calculation equation according to the local gas accumulation volume and the local gas-containing volume; The first calculation equation is: According to the first calculation equation, the gas evolution rate in water is calculated.

4. The gas content adjustment method according to claim 3, characterized in that: The overall parameters of the important plant water system include: the total volume of the important plant water system and the total gas-containing volume; According to the total volume parameter of the important plant water system and the gas release rate in the water, the total gas content in the important plant water system is obtained, which is specifically: The gas content in the important plant water system is calculated based on the total volume of the important plant water system, the total gas volume and the gas release rate in the water.

5. The method for adjusting the gas content according to claim 4, characterized in that: The gas content rate in the important plant water system is calculated based on the total volume of the important plant water system, the total gas-containing volume and the gas release rate in the water, including: A second calculation equation is established based on the total volume of important plant water systems, the total gas-containing volume and the gas release rate in water; The second calculation equation is: According to the second calculation equation, the gas content in the important plant water system is calculated.

6. The method for adjusting the gas content according to any one of claims 1 to 5, characterized in that: The exhaust operation of the local high-point pipeline in the important plant water system according to the total gas content in the important plant water system specifically includes: Determine whether the total gas content in the important plant water system is lower than or equal to a preset threshold: If so, it is determined that the total gas content in the important plant water system meets the requirements; If not, the local high-point pipeline is vented until the total gas content in the important plant water system is lower than or equal to a preset threshold.

7. The gas content adjustment method according to claim 6, characterized in that: Before performing the venting operation on the local high-point pipeline in the important plant water system according to the total gas content in the important plant water system, the method further includes: Acquire the working status of the important plant water system, where the working status of the important plant water system is an operating status or a shutdown status; According to the working status of the important plant water system, it is determined whether the first water delivery step or the second water delivery step is to be performed on the important plant water system: When the working state of the important plant water system is the running state, executing the first water delivery step; When the working state of the important plant water system is a shutdown state, the second water delivery step is performed.

8. The method for adjusting the gas content according to claim 7, characterized in that: The first water delivery step comprises: The cooling water input into the important plant water system is divided into the first part of cooling water and the second part of cooling water. Among them, the first part of cooling water directly enters the important plant water system. The second portion of cooling water is subjected to gas-liquid separation to obtain preliminary degassed water, which is then stored, and the first water delivery step is completed; The second water delivery step includes: delivering the preliminary degassed water into an important plant water system, and the second water delivery step ends.

9. A gas content regulating device, used for regulating the gas content of an important plant water system, characterized in that: include: A parameter acquisition unit, a first calculation unit, a second calculation unit and an adjustment unit; A parameter acquisition unit, used to acquire the overall parameters of the important plant water system and the gas accumulation detection parameters of the local high-point pipelines of the important plant water system; A first calculation unit, electrically connected to the parameter acquisition unit, is used to obtain the gas precipitation rate in water according to the gas accumulation detection parameter of the local high point pipeline; A second calculation unit is electrically connected to the parameter acquisition unit and the first calculation unit, and is used to obtain a total gas content in the important plant water system according to the overall parameters of the important plant water system and the gas precipitation rate in the water; The regulating unit is electrically connected to the second calculating unit and is used to perform exhaust operations on local high-point pipelines in the important plant water system according to the total gas content in the important plant water system.

10. The gas content regulating device according to claim 9, characterized in that: The regulating unit includes a first analysis module and an exhaust device; The first analysis module is used to determine whether the total gas content in the important plant water system is lower than or equal to a preset threshold: if so, determine that the total gas content in the important plant water system meets the requirement; if not, send a gas exhaust signal; The exhaust device is electrically connected to the analysis module, and is used to exhaust the local high-point pipeline according to the exhaust signal until the total gas content in the important plant water system is lower than or equal to a preset threshold.

11. The gas content regulating device according to claim 10, characterized in that: It also includes a state acquisition unit, a control unit and a water delivery execution device (21), The state acquisition unit is used to acquire the working state of the important plant water system, where the working state of the important plant water system is an operating state or a shutdown state; The control unit is electrically connected to the status acquisition unit, and is used to determine whether to perform the first water delivery step or the second water delivery step on the important plant water system according to the working state of the important plant water system: when the working state of the important plant water system is the operating state, a first signal is sent; when the working state of the important plant water system is the shutdown state, a second signal is sent, The water transfer execution device (21) is electrically connected to the control unit and is used to execute a first water transfer step when a first signal is received, or to execute a second water transfer step when a second signal is received.

12. The gas content regulating device according to claim 11, characterized in that: The water delivery execution device (21) is connected to the main pipe of the important plant water system, and the water delivery execution device (21) comprises a water suction culvert pipeline (1), a first pipeline (22) and a second pipeline (23), and the water suction culvert pipeline (1) is provided with a water suction culvert valve (16); One end of the first pipe (22) is connected to the water suction culvert pipe (1), and the other end is connected to the main pipe; one end of the second pipe (23) is connected to the water suction culvert pipe (1), and the other end is connected to the main pipe; the first pipe (22) and the second pipe (23) are arranged in parallel; The first pipeline (22) is provided with a first valve (17), a gas-water separation device (11), a water-sealed liquid accumulation pool (14) and a second valve (18) in sequence, and the second pipeline (23) is provided with a third valve (19); The water absorption culvert valve (16), the first valve (17), the second valve (18) and the third valve (19) are electrically connected to the control unit and are used to execute the first water delivery step when receiving the first signal: The water absorption culvert valve (16), the first valve (17) and the second valve (18) are opened, and the third valve (19) is closed, so as to divert the cooling water input into the important plant water system to obtain the first part of cooling water and the second part of cooling water. The first part of cooling water directly enters the important plant water system through the second pipeline (23). The second portion of cooling water enters the first pipeline (22), the gas-water separation device (11) is used to perform gas-liquid separation on the second portion of cooling water to obtain preliminary degassed water, and the water-sealed liquid storage tank (14) is used to store the preliminary degassed water; The water absorption culvert valve (16), the first valve (17), the second valve (18) and the third valve (19) are used to perform a second water delivery step when receiving a second signal: The third valve (19) is opened, and the water absorption culvert valve (16), the first valve (17) and the second valve (18) are controlled to be closed, so that the preliminary deaerated water in the water seal liquid accumulation pool (14) is input into the important plant water system.

13. The gas content regulating device according to claim 9, characterized in that: It also includes an ultrasonic detector, which is installed at the local high-point pipeline and is used to detect the amount of gas accumulated in the local high-point pipeline, that is, the local accumulated gas volume. The ultrasonic detector is electrically connected to the parameter acquisition unit and is used to upload the local accumulated gas volume to the parameter acquisition unit.

14. An important water system for a nuclear power plant, characterized in that: include: A mother pipe and a gas content regulating device as claimed in any one of claims 9 to 13, The main pipe has a local high-point pipeline, and the gas content regulating device is connected to the local high-point pipeline for exhausting the local high-point pipeline in the important plant water system.

15. The system according to claim 14, characterized in that It also includes a collector and a heat exchanger which are sequentially connected to the mother pipe; The local high point pipeline includes a first local high point pipeline and a second local high point pipeline, wherein the first local high point pipeline is located between the collector and the heat exchanger, and the second local high point pipeline is located downstream of the heat exchanger. The gas content regulating device comprises: an exhaust device, wherein the exhaust device comprises a first exhaust unit (9) and a second exhaust unit (10), wherein the first exhaust unit (9) is connected to the first local high point pipeline and is used to exhaust the first local high point pipeline, and the second exhaust unit (10) is connected to the second local high point pipeline and is used to exhaust the second local high point pipeline.

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