System and method for monitoring flow of a nuclear power plant cold source

Abstract

The present application relates to the field of nuclear power, in particular to a kind of nuclear power plant cold source flow monitoring system and method.The system includes cold source system, marking solution reservoir is installed in circulating water pump inlet, metering pump and check valve are arranged on the pipeline between marking solution reservoir and circulating water pump inlet;Sampling pipeline is arranged on condenser outlet main pipe, sampling pipeline is sampled by automatic sampling device, and marking solution concentration analyzer is analyzed by marking solution concentration;Marking solution concentration analyzer is connected with cold source flow calculation software by computer system.The method is: injecting known concentration of marking solution at circulating water pump inlet, so that marking solution uniformly enters the entire cold source system;Collect water sample at condensing steam outlet main pipe, and marking solution concentration analyzer detects the concentration of discharged marking solution;Calculate the flow of overall cold source;Real-time calculation of cold source flow is analyzed and compared by real-time flow and historical flow determination.The precision and reliability of the present application for monitoring cold source flow are improved.

Description

Technical Field

[0001] This invention relates to the field of nuclear power, and more particularly to a system and method for monitoring the flow of cold sources in nuclear power plants. Background Technology

[0002] The nuclear power plant's cooling system is the third loop. Its function is to provide filtered seawater to heat exchangers such as condensers, and to remove the heat generated during the operation of equipment in the turbine generator building and nuclear island building through heat exchange. The seawater after heat exchange is discharged into the sea through a siphon well.

[0003] In recent years, frequent occurrences of climate change and abnormal marine biodiversity have led to blockages in seawater intake pipelines at coastal nuclear power plants, resulting in forced power reductions and even emergency reactor shutdowns. These incidents pose a significant threat to the safe operation of nuclear power plants. Blockages in the cooling system can cause overload of the unit's drum filter and secondary filter, as well as pump tripping, and can also render the unit unusable for cooling, potentially leading to shutdowns and nuclear safety. Therefore, the flow rate of the cooling system is a key parameter monitored by nuclear power plant operators. However, due to the high sediment content in the seawater at some nuclear power plants, traditional differential pressure flow meters and ultrasonic flow meters suffer from low accuracy and reliability, affecting operators' judgment of the cooling system flow rate. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a system and method for monitoring the cold source flow in nuclear power plants, which solves the problems of low accuracy and low reliability of cold source flow monitoring under high sediment content conditions in existing systems and technologies, and provides nuclear power plant operators with a reliable backup reference for cold sources.

[0005] This invention provides a system for monitoring the flow of cold source in a nuclear power plant, including a cold source system, a labeled solution storage device, a metering pump, a check valve, a sampling pipeline, and a labeled solution concentration analyzer;

[0006] The labeling solution storage device is installed at the inlet of the circulating water pump, and a metering pump and a check valve are installed on the pipeline between the labeling solution storage device and the inlet of the circulating water pump.

[0007] The sampling line is installed on the condenser outlet header. The sampling line takes samples through an automatic sampling device and analyzes the concentration of the labeling solvent through a labeling solution concentration analyzer. The labeling solution concentration analyzer is connected to the cold source flow calculation software through a computer system. By comparing with a standard solution of known concentration, the dilution factor of the sample is calculated, and the cold source flow is calculated and displayed in real time.

[0008] In one specific embodiment of the present invention, the cold source system includes:

[0009] Water intake, with a valve plate installed at the water intake;

[0010] The water intake is connected to two sets of four-row bar screens, with each set of two bar screens connected to a drum filter.

[0011] The drum-shaped filter screen is connected to the condenser via a pipeline; a circulating water pump is installed on the pipeline.

[0012] A secondary filter screen is installed on the inlet side pipe of the condenser;

[0013] The condenser's outlet header is connected to the estuary.

[0014] In one specific embodiment of the present invention, the sampling pipeline is located in the trench near the estuary of the condenser outlet main pipe.

[0015] In one specific embodiment of the present invention, the automatic sampling device is a computer-controlled sampling isolation valve.

[0016] In one specific embodiment of the present invention, the inlet of both circulating water pumps is connected to the same marker solution storage device, and a metering pump and a check valve are respectively installed on the pipeline between the marker solution storage device and the inlet of each circulating water pump.

[0017] In one specific embodiment of the present invention, the detection accuracy of the labeled solution concentration analyzer is not less than 0.1 PPB.

[0018] The present invention also provides a method for monitoring the flow of cold sources in nuclear power plants using the system, comprising the following steps:

[0019] Step 1: Inject a labeling solution containing fluorescent dye of known concentration into the inlet of the circulating water pump, so that the labeling solution enters the entire cold source system evenly; the label is fully mixed with the seawater in the pipes of the cold source system;

[0020] The labeling solution containing fluorescent dye is non-toxic and has extremely low adsorption on organic and inorganic surfaces.

[0021] Step 2: Collect water samples at the condenser outlet header and use a labeling solution concentration analyzer to detect the concentration of the discharged labeling solution;

[0022] The computer calculates the total flow rate of the cold source based on the injection rate of the labeled solution, the initial concentration of the labeled solution, and the concentration of the labeled solution after passing through the cold source system.

[0023] Step 3: The computer saves and transmits the real-time calculated cold source flow to the operation monitoring system. By analyzing and comparing the real-time flow with the historical flow, if the measured flow exceeds the threshold range of the historical trend, it is determined that the cold source of the nuclear power plant has been blocked or throttled; if the calculated flow is within the threshold range of the temperature flow trend, it is determined that the cold source flow of the nuclear power plant is normal.

[0024] In one specific embodiment of the present invention, the fluorescent dye is Rhodamine WT.

[0025] In a specific embodiment of the present invention, the formula for calculating the overall flow rate of the cold source in step 2 is as follows:

[0026] Q2=(Q1×C1) / C2

[0027] Where Q1 is the solvent injection rate,

[0028] C1 represents the initial concentration of the labeled solution injected.

[0029] Q2 represents the total flow rate of the cold source.

[0030] C2 represents the concentration of the diluted labeling solution.

[0031] In one specific embodiment of the present invention, when collecting water samples, the sampling point is selected at the seawater discharge trench.

[0032] Compared with existing technologies, the system and method for monitoring the cold source flow of nuclear power plants according to this invention are applicable to seawater conditions with high sediment content, and have significant application value and promising prospects for promotion. By implementing this invention, the safety and reliability of the nuclear power plant cold source system can be effectively improved, reducing the risk of shutdown due to cold source blockage. This invention, through the use of low-adhering solution and high-precision detectors, can achieve high-precision measurement of the cold source flow of nuclear power plants, with errors controllable within 2%. This method enables continuous monitoring and is applicable to the complex piping systems of various nuclear power cold sources. This method causes minimal interference to the nuclear power cold source system and can utilize existing measuring instruments and pipeline designs, requiring no major modifications to the piping system. Attached Figure Description

[0033] Figure 1 A schematic diagram showing the structure of a system for monitoring the cold source flow in a nuclear power plant;

[0034] Figure 2 This diagram illustrates the flow measurement process.

[0035] Figure 3 This is a flowchart illustrating the flow calculation process.

[0036] In the diagram, 1. Water intake; 2. Bar screen cleaner; 3. Drum filter; 4. Circulating water pump; 5. Circulating water pump motor; 6. Secondary filter; 7. Condenser; 8. Labeled solution storage device; 9. Dosing pump; 10. Check valve; 11. Sea estuary; 12. Sampling isolation valve; 13. Labeled solution concentration analyzer. Detailed Implementation

[0037] To further understand the present invention, embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the present invention.

[0038] Embodiments of the present invention disclose a system for monitoring the cold source flow in a nuclear power plant, such as... Figure 1 As shown, it includes a cold source system, a label solution storage device 8, a metering pump 9, a check valve 10, a sampling line, and a label solution concentration analyzer 13;

[0039] The cooling source system includes:

[0040] Water intake 1, a valve plate is installed at water intake 1;

[0041] Water intake 1 is connected to two sets of four-row bar screen cleaners 2, and each set of two-row bar screen cleaners 2 is connected to a drum filter 3.

[0042] The drum filter 3 is connected to the condenser 7 via a pipe;

[0043] A circulating water pump 4 is installed on the pipeline;

[0044] The inlet of each of the two circulating water pumps 4 is connected to the same labeling solution storage 8. A metering pump 9 and a check valve 10 are respectively installed on the pipeline between the labeling solution storage and the inlet of each circulating water pump 4.

[0045] A secondary filter screen 6 is installed on the inlet side pipe of the condenser 7;

[0046] The outlet header of condenser 7 is connected to the sea inlet 11.

[0047] The sampling pipeline is installed on the outlet main pipe of condenser 7. Preferably, the sampling pipeline is installed in the trench near the estuary 11 of the outlet main pipe of condenser 7.

[0048] The sampling pipeline takes samples through an automatic sampling device and analyzes the concentration of the labeling solvent through a labeling solution concentration analyzer 13; the automatic sampling device is a computer-controlled sampling isolation valve 12.

[0049] The label solution concentration analyzer 13 is a high-precision label solution concentration analyzer, and the detection accuracy of the label solution concentration analyzer 13 is not less than 0.1 ppb.

[0050] The labeled solution concentration analyzer is connected to a computer system and cold source flow calculation software. By comparing the sample with a standard solution of known concentration, it calculates the dilution factor of the sample and calculates and displays the cold source flow in real time.

[0051] Embodiments of the present invention also disclose a method for monitoring the cold source flow of a nuclear power plant using the system described above, such as... Figures 2-3As shown, it includes the following steps:

[0052] Step 1: Inject a labeling solution containing fluorescent dye of known concentration into the inlet of the circulating water pump, so that the labeling solution enters the entire cold source system evenly; the label is fully mixed with the seawater in the pipes of the cold source system, and discharged into the sea after passing through the drum filter 3, the secondary filter 6 and the condenser 7.

[0053] The labeling solution containing fluorescent dye is non-toxic and has extremely low adsorption on organic and inorganic surfaces.

[0054] The fluorescent dye is preferably Rhodamine WT.

[0055] Step 2: Collect water samples at the condenser outlet header. When collecting water samples, the sampling point is selected at the seawater discharge trench.

[0056] By selecting the injection and sampling points for the labeling solution, it is ensured that the labeling solution can be fully mixed in the pipeline before sampling and testing.

[0057] The label solution concentration analyzer 13 detects the concentration of the discharged label solution;

[0058] The computer calculates the total flow rate of the cold source based on the injection rate of the labeled solution, the initial concentration of the labeled solution, and the concentration of the labeled solution after passing through the cold source system.

[0059] The formula for calculating the total flow rate of the cold source is:

[0060] Q1×C1+Q2×C0=(Q1+Q2)×C2

[0061] Since the seawater inhaled by nuclear power plants generally does not contain labeled solvents, and the flow rate to be measured, Q2, is much larger than 90,000 t / h, which is several orders of magnitude higher than Q1, the formula can be simplified to:

[0062] Q2=(Q1×C1) / C2

[0063] Where Q1 is the solvent injection rate,

[0064] C0 represents the concentration of the labeled solvent in the seawater before the addition of the labeled solution;

[0065] C1 represents the initial concentration of the labeled solution injected.

[0066] Q2 represents the total flow rate of the cold source.

[0067] C2 represents the concentration of the diluted labeling solution.

[0068] Step 3: The computer saves and transmits the real-time calculated cold source flow to the operation monitoring system. By analyzing and comparing the real-time flow with the historical flow, if the measured flow exceeds the threshold range of the historical trend, it is determined that the cold source of the nuclear power plant has been blocked or throttled; if the calculated flow is within the threshold range of the temperature flow trend, it is determined that the cold source flow of the nuclear power plant is normal.

[0069] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0070] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A system for monitoring the flow rate of a cold source in a nuclear power plant, comprising a cold source system, characterized in that, It also includes: labeled solution storage, metering pump, check valve, sampling line, labeled solution concentration analyzer; The labeling solution storage device is installed at the inlet of the circulating water pump, and a metering pump and a check valve are installed on the pipeline between the labeling solution storage device and the inlet of the circulating water pump. The sampling line is installed on the condenser outlet header. The sampling line takes samples through an automatic sampling device and analyzes the concentration of the labeling solvent through a labeling solution concentration analyzer. The labeling solution concentration analyzer is connected to the cold source flow calculation software through a computer system. By comparing with a standard solution of known concentration, the dilution factor of the sample is calculated, and the cold source flow is calculated and displayed in real time.

2. The system for monitoring the cold source flow of a nuclear power plant according to claim 1, characterized in that, The cooling source system includes: Water intake, with a valve plate installed at the water intake; The water intake is connected to two sets of four-row bar screen cleaners, with each set of two bar screen cleaners connected to a drum filter. The drum-shaped filter screen is connected to the condenser via a pipeline; a circulating water pump is installed on the pipeline. A secondary filter screen is installed on the inlet side pipe of the condenser; The condenser's outlet header is connected to the estuary.

3. The system for monitoring the cold source flow of a nuclear power plant according to claim 1, characterized in that, The sampling pipeline is located in the trench near the estuary of the condenser outlet header.

4. The system for monitoring the cold source flow of a nuclear power plant according to claim 1, characterized in that, The automatic sampling device is a computer-controlled sampling isolation valve.

5. The method for monitoring the cold source flow in a nuclear power plant according to claim 2, characterized in that, The inlet of both circulating water pumps is connected to the same marker solution storage device, and a metering pump and a check valve are respectively installed on the pipeline between the marker solution storage device and the inlet of each circulating water pump.

6. The system for monitoring the cold source flow of a nuclear power plant according to claim 1, characterized in that, The detection accuracy of the labeled solution concentration analyzer is not less than 0.1 PPB.

7. A method for monitoring the cold source flow of a nuclear power plant using the system described in any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1: Inject a labeling solution containing fluorescent dye of known concentration into the inlet of the circulating water pump, so that the labeling solution enters the entire cold source system evenly; the label is fully mixed with the seawater in the pipes of the cold source system; The labeling solution containing fluorescent dye is non-toxic and has extremely low adsorption on organic and inorganic surfaces. Step 2: Collect water samples at the condenser outlet header and use a labeling solution concentration analyzer to detect the concentration of the discharged labeling solution; The computer calculates the total flow rate of the cold source based on the injection rate of the labeled solution, the initial concentration of the labeled solution, and the concentration of the labeled solution after passing through the cold source system. Step 3: The computer saves and transmits the real-time calculated cold source flow to the operation monitoring system. By analyzing and comparing the real-time flow with the historical flow, if the measured flow exceeds the threshold range of the historical trend, it is determined that the cold source of the nuclear power plant has been blocked or throttled; if the calculated flow is within the threshold range of the temperature flow trend, it is determined that the cold source flow of the nuclear power plant is normal.

8. The method for monitoring the cold source flow in a nuclear power plant according to claim 7, characterized in that, The fluorescent dye is Rhodamine WT.

9. The method for monitoring the cold source flow in a nuclear power plant according to claim 7, characterized in that, In step 2, the formula for calculating the total flow rate of the cold source is: Q2 = (Q1 × C1) / C2 Where Q1 is the solvent injection rate, C1 represents the initial concentration of the labeled solution injected. Q2 represents the total flow rate of the cold source. C2 represents the concentration of the diluted labeling solution.

10. The method for monitoring the cold source flow of a nuclear power plant according to claim 7, characterized in that, When collecting water samples, the sampling point is selected at the seawater discharge trench.

Images