A method for water quality management of long-term static water tanks in nuclear power plants

Abstract

The present invention discloses a method for managing the water quality of a long-term static water tank in a nuclear power plant, comprising: S1, determining key parameters that affect water quality changes; S2, conducting experiments based on the key parameters to analyze and obtain water quality change trends; S3, determining a management strategy for the water quality in the long-term static water tank in the nuclear power plant based on the water quality change trends to ensure that the water quality meets the target values ​​of the key parameters. The present invention can provide a basis for the management of the water quality of the long-term static water tank by studying the change trends of the water quality in the long-term static water tank, thereby reducing or avoiding the corrosion of equipment and pipelines in the long-term static water tank, and controlling the growth of microorganisms.

Description

Technical Field

[0001] The invention belongs to the field of nuclear technology, and in particular relates to a method for managing water quality of a long-term static water tank in a nuclear power plant. Background Art

[0002] Hualong One is a third-generation nuclear power unit independently developed by my country. This reactor type adopts a "combination of active and passive" safety system. Among them, the passive containment heat removal system (PCS) and the secondary side passive residual heat removal system (PRS) are both passive heat exchange systems. Figure 6 As shown in the figure, the PCS and PRS share a heat exchange water tank, the heat exchanger of the PRS is immersed in the heat exchange water tank of the PCS, and the water in the heat exchange water tank of the PCS is also the cold source medium of the heat exchanger of the PCS. Since both the PCS and the PRS are measures to deal with accidents beyond the design basis, under normal operating conditions, both are in standby status for a long time, and the heat exchange water tank is basically in a static state during the system standby period, which will not only cause the growth of microorganisms in the water tank, but also cause scaling and corrosion of the equipment and pipes in the heat exchange water tank, resulting in a decrease in the heat exchange capacity of the equipment or failure. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for water quality management of long-term static water tanks in nuclear power plants in view of the above-mentioned deficiencies in the prior art. By studying the changing trend of the water quality of long-term static water tanks, a basis is provided for the management of the water quality of long-term static water tanks, thereby reducing or avoiding corrosion of equipment and pipelines in long-term static water tanks, and controlling the growth of microorganisms.

[0004] The technical solution of the present invention to solve the above technical problems is:

[0005] The present invention provides a method for managing water quality of a long-term static water tank in a nuclear power plant.

[0006] A method for managing water quality of a long-term static water tank in a nuclear power plant, comprising:

[0007] S1, determine the key parameters that affect water quality changes;

[0008] S2, conduct experiments based on key parameters to analyze the trend of water quality changes;

[0009] S3, based on the water quality change trend, determine the management strategy for the water quality in the long-term static water tanks of the nuclear power plant to ensure that the water quality meets the target values ​​of key parameters.

[0010] Preferably, the key parameters include the contents of chloride ions, fluoride ions, sulfate, sodium ions, as well as conductivity, pH, and turbidity in the water in the long-term static water tank of the nuclear power plant;

[0011] The experiment is carried out according to the key parameters, comprising the following steps:

[0012] S201, constructing a group of simulated water tanks according to the long-term static water tanks of the nuclear power plant, wherein a part of the simulated water tanks are experimental water tanks and another part of the simulated water tanks are comparative experimental water tanks;

[0013] S202, placing both the experimental water tank and the comparative experimental water tank in the same environment as the long-term static water tank of the nuclear power plant, filling the two with equal amounts of desalted water from the nuclear power plant, and adding chemicals to the comparative experimental water tanks, so that the pH value of the water in each comparative experimental water tank is distributed in a gradient and the pH value is between 5 and 12, so as to form initial water quality;

[0014] S203, taking equal amounts of water samples from each experimental water tank and the comparative experimental water tank at regular intervals, and detecting the contents of chloride ions, fluoride ions, sulfate, sodium ions, as well as conductivity, pH, and turbidity in each water sample to obtain experimental data records;

[0015] S204, analyzing the water quality change trends in each experimental water tank and the comparative experimental water tank according to the experimental data records.

[0016] Preferably, the drug added in step S202 is hydrogen peroxide or trisodium phosphate crystals.

[0017] Preferably, there are three comparative experimental water tanks, which are respectively recorded as 2# comparative experimental water tank, 3# comparative experimental water tank, and 4# comparative experimental water tank, wherein:

[0018] Add drugs to the comparative experimental water tanks respectively so that the pH value of the water in each comparative experimental water tank is distributed in a gradient and the pH value is between 5 and 12, specifically including:

[0019] Add hydrogen peroxide to the 2# comparative experimental water tank until the pH value of the water in the 2# comparative experimental water tank reaches 5;

[0020] Add hydrogen peroxide to the 3# comparative experimental water tank until the pH value of the water in the 3# comparative experimental water tank is 5.5;

[0021] Trisodium phosphate crystals were added to the 4# comparative experimental water tank until the pH value of the water in the 4# comparative experimental water tank reached 11.3.

[0022] Preferably, the key parameter also includes microbial content; and the step S203 also includes: detecting the microbial content in each water sample.

[0023] Preferably, the frequency of taking water samples and detecting the microbial content in the water samples in step S203 is one week to one month.

[0024] Preferably, each simulated water tank includes a water tank body and a water sealing device, one end of the water sealing device is connected to the water tank body, and the other end of the water sealing device is connected to the external environment, and taking equal amounts of water samples from each experimental water tank and the comparative experimental water tank includes: sampling from the water tank body of each experimental water tank and sampling from the water sealing device of each experimental water tank, and, sampling from the water tank body of each comparative experimental water tank and sampling from the water sealing device of each comparative experimental water tank.

[0025] Preferably, in step S3, determining a management strategy for water quality in a long-term static water tank of a nuclear power plant according to a water quality change trend comprises the following steps:

[0026] S301, determine the target value of each key parameter based on the water quality requirements for long-term static water tanks in nuclear power plants;

[0027] S302, comparing the experimental values ​​of each key parameter in the experimental data record with its target value:

[0028] When the experimental value of any key parameter is less than or equal to the target value of the key parameter, it is determined that the key parameter meets the standard; when the experimental value of any key parameter is greater than the target value, it is determined that the key parameter does not meet the standard;

[0029] S303: Develop a water quality adjustment plan based on the comparison results.

[0030] Preferably, the S303 specifically includes:

[0031] Based on the comparison results, the impact of each key parameter on water quality is analyzed, and suggestions for drug addition and environmental condition control are given to form the water quality adjustment plan.

[0032] Preferably, when it is determined that all key parameters in all experimental water tanks and all comparative experimental water tanks do not meet the standards before the end of the experimental period, the method further comprises:

[0033] Adjust the pH value of the initial water quality in each of the experimental water tank and the comparative experimental water tank, and re-execute steps S202-S204.

[0034] The method for managing the water quality of a long-term static water tank in a nuclear power plant of the present invention simulates the changes in the water quality in the long-term static water tank in the nuclear power plant by constructing a simulation water tank, thereby providing a basis for the management of the water quality of the long-term static water tank, thereby reducing or avoiding the corrosion of equipment and pipelines in the long-term static water tank, and controlling the growth of microorganisms, thereby reducing the corrosion of stainless steel equipment in contact with the water in the long-term static water tank in the nuclear power plant, and ensuring the heat exchange efficiency of the heat exchange equipment using the water in the long-term static water tank in the nuclear power plant as a cold source. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a flow chart of a method for managing water quality of a long-term static water tank in a nuclear power plant according to an embodiment of the present invention;

[0036] Figure 2 The experimental data record table in Example 1 of the present invention;

[0037] Figure 3 This is a graph showing the trend of chloride ion content in Example 1 of the present invention;

[0038] Figure 4 The experimental data record table in Example 2 of the present invention;

[0039] Figure 5 This is a trend diagram of chloride ion content in Example 2 of the present invention;

[0040] Figure 6 It is a schematic diagram of the structure of a passive containment heat removal system and a secondary side passive residual heat removal system in the prior art. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0042] Example 1

[0043] like Figure 1 As shown, this embodiment discloses a method for managing water quality of a long-term static water tank in a nuclear power plant, which includes:

[0044] S1, determine the key parameters that affect water quality changes;

[0045] S2, conduct experiments based on key parameters to analyze the trend of water quality changes;

[0046] S3, based on the water quality change trend, determine the management strategy for the water quality in the long-term static water tanks of the nuclear power plant to ensure that the water quality meets the target values ​​of key parameters.

[0047] Specifically, for long-term static water tanks in nuclear power plants, the deterioration of water quality mainly depends on the following factors: environmental conditions (including air salt content, humidity, etc.); surface area of ​​the water tank in contact with the environment; water volume in the water tank; and water quality management plan.

[0048] In some embodiments, the key parameters in the present method may include the contents of chloride ions, fluoride ions, sulfate, sodium ions, as well as conductivity, pH, turbidity, etc. in the water in the water tank. Of course, it may also be a part of the above key parameters, that is, the key parameters may also be a combination of one or more of the chloride ion content, fluoride ion content, sulfate content, sodium ion content, conductivity, pH, and turbidity.

[0049] The method includes the following steps:

[0050] S201, constructing a group of simulated water tanks according to the structure and specifications of the long-term static water tanks of the nuclear power plant, wherein a part of the simulated water tanks are experimental water tanks and another part of the simulated water tanks are comparative experimental water tanks;

[0051] S202, placing both the experimental water tank and the comparative experimental water tank in the real environment where the long-term static water tank of the nuclear power plant is located or in an environment that is the same as or similar to the real environment where the long-term static water tank of the nuclear power plant is located, filling the two with equal amounts of demineralized water from the nuclear power plant, and adding chemicals to the comparative experimental water tank, so that the pH value of the water in each comparative experimental water tank is distributed in a gradient and the pH value is between 5 and 12, so as to form initial water quality;

[0052] S203, taking equal amounts of water samples from each experimental water tank and the comparative experimental water tank at regular intervals, and detecting the contents of chloride ions, fluoride ions, and sulfate, as well as conductivity, pH, and turbidity in each water sample to obtain experimental data records;

[0053] S204, analyzing the water quality change trends in each experimental water tank and the comparative experimental water tank according to the experimental data records.

[0054] In this embodiment, the long-term static water tanks of a nuclear power plant mainly refer to the heat exchange water tanks in the passive containment heat removal system (PCS) and the secondary side passive residual heat removal system (PRS). Of course, it can also be other water tanks in the nuclear power plant that are in a static state for a long time. The structure of the simulated water tank is the same as or similar to the structure of the long-term static water tanks of the nuclear power plant.

[0055] In some embodiments, the drug added in step S202 may be an acidic or alkaline drug such as hydrogen peroxide or trisodium phosphate crystals.

[0056] In some embodiments, the number of experimental water tanks is preferably one (or more), and the number of comparative experimental water tanks is more. By setting up a comparison between comparative experimental water tanks (2#, 3#, and 4#) and experimental water tank 1#, the influence of pH value on the water quality of long-term stationary water tanks in nuclear power plants can be understood, a database of the influence of pH value on the water quality of long-term stationary water tanks in nuclear power plants can be established, and a spectrum of pH values ​​from 5 to 12 can be formed, providing a basis for managing the water quality of long-term stationary water tanks in nuclear power plants.

[0057] In this embodiment, the number of experimental water tanks is preferably one, recorded as 1# experimental water tank, and the number of comparative experimental water tanks is preferably three, recorded as 2# comparative experimental water tank, 3# comparative experimental water tank, and 4# comparative experimental water tank, respectively, wherein: hydrogen peroxide is added to 2# comparative experimental water tank until the hydrogen peroxide content in 2# comparative experimental water tank is 300ppm, at which time, the corresponding pH value of the water is about 5; hydrogen peroxide is added to 3# comparative experimental water tank until the hydrogen peroxide content in 3# comparative experimental water tank is 70ppm, at which time, the corresponding pH value of the water is about 5.5; trisodium phosphate crystals are added to 4# comparative experimental water tank until the phosphate ion content in 4# comparative experimental water tank is 100-500ppm, at which time, the corresponding pH value of the water is about 11.3, more precisely, the pH value is 11.2-11.5.

[0058] In some embodiments, the key parameter in the method may also include the microbial content, and step S203 may also include: detecting the content of microorganisms (such as algae, bacteria) in each water sample.

[0059] In some embodiments, the frequency of taking water samples and detecting the microbial content in the water samples in step S203 is preferably one week to one month, which can be adjusted according to actual conditions.

[0060] In some embodiments, in step S3, determining a management strategy for water quality in a long-term static water tank of a nuclear power plant according to a water quality change trend includes the following steps:

[0061] S301, determine the target value of each key parameter based on the water quality requirements for long-term static water tanks in nuclear power plants;

[0062] Among them, in this embodiment, the water quality of the long-term static water tank of the nuclear power plant should meet the requirements shown in Table 1, for example, the sodium ion does not exceed 0.2 mg / kg, the chloride ion does not exceed 0.15 mg / kg, the fluoride ion does not exceed 0.15 mg / kg, and the sulfate ion does not exceed 0.15 mg / kg.

[0063] Table 1 Water quality requirements for long-term static water tanks in nuclear power plants

[0064]

[0065] S302, comparing the experimental value of each key parameter in the experimental data record with its target value: when the experimental value of the key parameter is less than or equal to the target value of the key parameter, it is determined that the key parameter meets the standard; when the experimental value of the key parameter is greater than the target value, it is determined that the key parameter does not meet the standard;

[0066] S303: Develop a water quality management plan based on the comparison results.

[0067] Specifically, step S303 specifically includes: analyzing the influence of each key parameter on water quality according to the comparison results, giving suggestions for adding drugs and controlling environmental conditions to form the water quality adjustment plan, so as to control the above-mentioned key parameters that do not meet the standards of the water in the long-term static water tank of the nuclear power plant to meet the standards.

[0068] The following is a detailed description of step S3 of the method using an experimental water tank (1#) and three comparative experimental water tanks (2#, 3#, and 4#) as examples, wherein the detection frequency is 30 days, and the data of each detection is calculated according to Figure 2 The change trend of chloride ion content is recorded in the table shown in Figure 3 As shown, the horizontal axis is the detection time (unit / day) and the vertical axis is the chloride ion content (unit / ppm, 1ppm=1mg / kg).

[0069] Depend on Figure 3It can be seen that the chloride ion content in the 1# experimental water tank without adding any chemicals increased significantly faster than the chloride ion content in the 2# comparative experimental water tank, 3# comparative experimental water tank, and 4# comparative experimental water tank with added chemicals. In addition, the chloride ion content in the 1# experimental water tank was about 0.25ppm (i.e., about 0.25mg / kg). When the experiment was carried out to the eighth test (the 240th day), it had exceeded the chloride ion content target value (≤0.15mg / kg) in the long-term static water quality requirements of the nuclear power plant. The chloride ion content in the 2# comparative experimental water tank, 3# comparative experimental water tank, and 4# comparative experimental water tank (all below 0.1ppm, i.e., below 0.1mg / kg) all met the requirements of the nuclear power plant. The target value of chloride ion content in the water quality of long-term static water tanks is required, that is, adding hydrogen peroxide or trisodium phosphate crystals can effectively inhibit the increase rate of chloride ion content in water, and the chloride ion content in the 3# comparative experimental water tank with more hydrogen peroxide added increases slower than the chloride ion content in the 2# comparative experimental water tank with less hydrogen peroxide added, that is, the higher the hydrogen peroxide concentration, the better the inhibition effect. In addition, the increase rate of chloride ion content in the 3# comparative experimental water tank with more hydrogen peroxide (300ppm) is similar to the increase rate of chloride ion content in the 2# comparative experimental water tank with trisodium phosphate crystals added, that is, the inhibitory effect of adding trisodium phosphate crystals is similar to that of hydrogen peroxide at 300ppm. Therefore, the increase rate of chloride ion content can be inhibited by adding hydrogen peroxide or trisodium phosphate crystals and other chemicals to the water in the long-term static water tanks of nuclear power plants.

[0070] In some embodiments, when various key parameters of a simulated water tank meet the standards throughout a preset experimental period (e.g., 12 months), that is, the experimental results meet expectations, the experimental conditions of the simulated water tank can be used as a basis for managing the water quality of the long-term static water tanks of the nuclear power plant.

[0071] In some embodiments, when it is determined that each key parameter in all experimental water tanks and all comparative experimental water tanks does not meet the standard before the end of the experimental cycle, it is judged that the experimental results do not meet expectations, and the experimental conditions of all experimental water tanks and all comparative experimental water tanks are not conducive to managing the water quality of the long-term static water tanks of the nuclear power plant to prevent the deterioration of water quality. At this time, the method further includes:

[0072] Adjust the experimental conditions such as the pH value of the initial water quality in the experimental water tank and the comparative experimental water tank, and re-execute steps S202-S204.

[0073] The method for managing the water quality of a long-term stationary water tank in a nuclear power plant of this embodiment constructs a simulated water tank to simulate the changes in the water quality in the long-term stationary water tank in the nuclear power plant, thereby providing a basis for the management of the water quality of the long-term stationary water tank, and controlling the ion content and microbial growth related to stainless steel corrosion in the water tank, thereby reducing the corrosion of stainless steel equipment in contact with the water in the long-term stationary water tank in the nuclear power plant, thereby ensuring the heat exchange efficiency of the heat exchange equipment using the water in the long-term stationary water tank in the nuclear power plant as a cold source.

[0074] Example 2

[0075] This embodiment discloses a method for studying the water quality of a long-term static water tank in a nuclear power plant. Compared with the embodiment 1, the difference is that:

[0076] Each simulated water tank in the present embodiment includes two interconnected parts, namely a water tank body and a water seal device. One end of the water seal device is connected to the water tank body, and the other end thereof is connected to the external environment. That is, the water tank bodies of the experimental water tank and the comparative experimental water tank are respectively connected to the external environment through their respective corresponding water seal devices. Taking equal amounts of water samples from each experimental water tank and the comparative experimental water tank for each test includes: sampling from the water tank body of each experimental water tank and sampling from the water seal device of each experimental water tank, and sampling from the water tank body of each comparative experimental water tank and sampling from the water seal device of each comparative experimental water tank.

[0077] In this embodiment, the water tank body is in a cubic shape, and its water capacity is preferably 1m 3 , its material is consistent with that of the long-term static water tank of the nuclear power plant, and a dosing port for adding medicines is provided on the water tank body. The water seal device can adopt a riser, the upper end of the riser is open to connect to the external environment, and the bottom end of the riser is connected to the water tank body through a connecting pipe to simulate the U-shaped water seal structure on the long-term static water tank of the nuclear power plant. The riser is preferably a stainless steel pipe, and the size of the contact surface between the riser and the external environment is as close as possible to the actual situation. In this embodiment, the diameter of the riser can be 500-700mm, preferably 600mm. A baffle made of PVC material is provided at the connection between the connecting pipe and the water tank or the riser, and one or more through holes are provided on the baffle to adjust the water flow rate between the riser and the water tank body.

[0078] The following is an example of an experimental water tank (denoted as 5#) and a comparative experimental water tank (denoted as 6#). The same amount of demineralized water from the nuclear power plant is filled into the 5# experimental water tank and the 6# comparative experimental water tank. At this time, the water quality parameters of the two are shown in Table 2. At the beginning of the experiment, hydrogen peroxide (chemical) is added to the 6# comparative experimental water tank to make the hydrogen peroxide content in the water of the 6# comparative experimental water tank 70ppm (at this time, the pH value of the water becomes about 5.5). No chemical is added to the 5# experimental water tank. At regular intervals (such as one month or one week, the frequency of subsequent testing is adjusted according to the previous test results), samples are taken from the water tank bodies and risers of the 5# experimental water tank and the 6# comparative experimental water tank for testing. The testing is continuous for 13 months, and the data of each test is calculated according to the following table: Figure 4 The table shown is used to record and describe step S3 in the method of this embodiment in detail.

[0079] Table 2 Water quality parameters before the experiment

[0080]

[0081] It can be seen from Table 2 that the sodium, chlorine, fluorine, sulfate, conductivity and turbidity in the 5# experimental water tank and the 6# comparative experimental water tank are basically the same, that is, the initial water quality of the comparative experimental water tank 5# and the experimental water tank is basically the same.

[0082] Taking the key parameter chloride ion content as an example, Figure 5 The following is a trend chart of the key parameter chloride ion content in the water in the water tank body / standpipe of the 5# experimental water tank and the 6# comparative experimental water tank. The horizontal axis is the detection time (unit / month) and the vertical axis is the chloride ion content (unit / ppb). Figure 5 It can be seen that:

[0083] (1) The chloride ion content at the same detection time is as follows: the riser of the 5# experimental water tank (referred to as the 5# riser)> the riser of the 6# comparative experimental water tank (referred to as the 6# riser)> the water tank body of the 6# comparative experimental water tank (referred to as the 5# water tank body)> the water tank body of the 5# experimental water tank (referred to as the 5# water tank body), and the chloride ion content of the water in each riser and each water tank body increases with time. The reasons for this are mainly that the riser is connected to the external atmospheric environment, and the chlorine content in the air (especially in coastal areas) is relatively high. The chloride ions in the air dissolve in the water, resulting in a higher sodium ion content in the water in the riser. As the sodium ion content in the water in the riser increases, it diffuses into the water tank body from the through holes on the baffle, causing the chloride ion content in the water in the water tank body to also increase. Moreover, the chloride ion content in the water in the water tank body is much smaller than the chloride ion content in the water in the corresponding riser. In other words, the baffle between the riser and the water tank body plays a good isolation role, reducing the impact of various ions such as chloride ions in the air on the water quality in the water tank body.

[0084] (2) The chloride ion content in the water in the 6# water tank body is greater than that in the 5# water tank body. The main reason is that when adding chemicals to the 6# comparative experimental water tank, the dosing port on the 6# water tank body needs to be opened, resulting in direct contact between the 6# water tank body and the air in the external environment, causing the chloride ions in the air to enter the 6# water tank body, thereby increasing the chloride ion content in the water in the 6# water tank body.

[0085] (3) After 13 months of the experiment, the chloride ion content in the water in the 5# riser has exceeded the target value (150 ppb), and according to the trend of the chloride ion content over time, the chloride ion content will continue to increase with time. In addition, the chloride ion content in the water in the 5# riser is greater than that in the water in the 6# riser, indicating that the addition of hydrogen peroxide can inhibit the increase of the chloride ion content in the water in the riser, and the dosing effect is significant.

[0086] (4) The chloride ion content in the water in the 6# water tank body at the same detection time is less than the chloride ion content in the water in the 6# riser, indicating that the small flow connection between the baffle and the water tank body and the addition of hydrogen peroxide can slow down the increase of chloride ion concentration.

[0087] The method for managing the water quality of a long-term static water tank in a nuclear power plant of this embodiment, by constructing a simulated water tank to simulate the changes in the water quality in the long-term static water tank in the nuclear power plant, provides a basis for the management of the water quality of the long-term static water tank, thereby reducing or avoiding the corrosion of equipment and pipelines in the long-term static water tank, and controlling the growth of microorganisms, thereby reducing the corrosion of stainless steel equipment in contact with the water in the long-term static water tank of the nuclear power plant, and ensuring the heat exchange efficiency of the heat exchange equipment using the water in the long-term static water tank of the nuclear power plant as a cold source.

[0088] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but 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 considered to be within the scope of protection of the present invention.

Claims

1. A method for managing water quality of a long-term static water tank in a nuclear power plant, comprising: S1, determine the key parameters that affect water quality changes; S2, conduct experiments based on key parameters to analyze the trend of water quality changes; S3, determine the management strategy for water quality in long-term static water tanks of nuclear power plants based on the water quality change trend to ensure that the water quality meets the target values ​​of key parameters; The key parameters include the contents of chloride ions, fluoride ions, sulfate, conductivity, pH, and turbidity in the water in the long-term static water tank of the nuclear power plant. The experiment based on the key parameters includes the following steps: S201, constructing a group of simulated water tanks according to the long-term static water tanks of the nuclear power plant, wherein a part of the simulated water tanks are experimental water tanks and another part of the simulated water tanks are comparative experimental water tanks; S202, placing both the experimental water tank and the comparative experimental water tank in the same environment as the environment of the long-term static water tank of the nuclear power plant, filling the two with equal amounts of desalted water from the nuclear power plant, and adding chemicals to the comparative experimental water tanks, wherein the chemicals are hydrogen peroxide or trisodium phosphate crystals, so that the pH value of the water in each comparative experimental water tank is distributed in a gradient and the pH value is between 5 and 12, so as to form initial water quality; S203, taking equal amounts of water samples from each experimental water tank and the comparative experimental water tank at regular intervals, and testing the contents of chloride ions, fluoride ions, sulfate, sodium ions, microorganisms, and conductivity, pH, and turbidity in each water sample to obtain experimental data records; S204, analyzing the water quality change trends in each experimental water tank and the comparative experimental water tank according to the experimental data records.

2. The method for water quality management of a long-term static water tank in a nuclear power plant according to claim 1, characterized in that: There are three comparative experimental water tanks, which are respectively denoted as 2# comparative experimental water tank, 3# comparative experimental water tank, and 4# comparative experimental water tank. Add drugs to the comparative experimental water tanks respectively so that the pH value of the water in each comparative experimental water tank is distributed in a gradient and the pH value is between 5 and 12, specifically including: Add hydrogen peroxide to the 2# comparative experimental water tank until the pH value of the water in the 2# comparative experimental water tank reaches 5; Add hydrogen peroxide to the 3# comparative experimental water tank until the pH value of the water in the 3# comparative experimental water tank is 5.5; Trisodium phosphate crystals were added to the 4# comparative experimental water tank until the pH value of the water in the 4# comparative experimental water tank reached 11.

3.

3. The method for water quality management of a long-term static water tank in a nuclear power plant according to claim 1, characterized in that: The key parameters also include microbial content; The step S203 also includes: detecting the microbial content in each water sample.

4. The method for water quality management of a long-term static water tank in a nuclear power plant according to claim 3, characterized in that: The frequency of taking water samples and detecting the microbial content in the water samples in step S203 is one week to one month.

5. The method for water quality management of a long-term static water tank in a nuclear power plant according to claim 1, characterized in that: Each simulated water tank includes a water tank body and a water seal device, one end of the water seal device is connected to the water tank body, and the other end is connected to the external environment. The steps of taking equal amounts of water samples from each experimental water tank and the comparative experimental water tank include: Samples were taken from the water tank body of each experimental water tank and from the water seal device of each experimental water tank, and samples were taken from the water tank body of each comparative experimental water tank and from the water seal device of each comparative experimental water tank.

6. The method for water quality management of a long-term static water tank in a nuclear power plant according to any one of claims 1 to 5, characterized in that: In step S3, the management strategy of the water quality in the long-term static water tank of the nuclear power plant is determined according to the water quality change trend, including the following steps: S301, determine the target value of each key parameter based on the water quality requirements for long-term static water tanks in nuclear power plants; S302, comparing the experimental values ​​of each key parameter in the experimental data record with its target value: When the experimental value of any key parameter is less than or equal to the target value of the key parameter, it is determined that the key parameter meets the target. When the experimental value of any key parameter is greater than the target value, it is determined that the key parameter does not meet the standard; S303: Develop a water quality adjustment plan based on the comparison results.

7. The method for water quality management of a long-term static water tank in a nuclear power plant according to claim 6, characterized in that: The S303 specifically includes: Based on the comparison results, the impact of each key parameter on water quality is analyzed, and suggestions for drug addition and environmental condition control are given to form the water quality adjustment plan.

8. The method for water quality management of a long-term static water tank in a nuclear power plant according to claim 7, characterized in that: When it is determined that all key parameters in all experimental water tanks and all comparative experimental water tanks do not meet the standards before the end of the experimental period, the method further includes: Adjust the pH value of the initial water quality in each of the experimental water tank and the comparative experimental water tank, and re-execute steps S202-S204.

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