A precision testing device for a nuclear power plant main feed water flowmeter

Abstract

The present application belongs to the technical field of industrial equipment testing, and particularly relates to a nuclear power plant main feed water flowmeter precision testing device. The device comprises a fluid generating module, a flowmetering reference benchmark module and a main feed water flowmeter precision testing section. The fluid generating module is connected to the flowmetering reference benchmark module through a pipeline, the flowmetering reference benchmark module is connected to the main feed water flowmeter precision testing section through a pipeline, and the main feed water flowmeter precision testing section is connected to the fluid generating module through a pipeline to form a closed loop. The pipelines are coated with heat preservation materials. The present application has the advantages that it can restore the complex flow field in the main feed water pipeline of a nuclear power unit in a laboratory, and provide a nearly real working condition environment for the flowmeter. By establishing a precise metering benchmark, the main feed water flowmeter can be calibrated with high precision to ensure the accuracy and reliability of the measurement results, and provide key data support for engineering application.

Description

Technical Field

[0001] This invention belongs to the field of industrial equipment testing technology, specifically relating to a device for testing the accuracy of a main feedwater flow meter in a nuclear power plant. Background Technology

[0002] Most operating nuclear power units use differential pressure flow meters for main feedwater measurement, including orifice plate flow meters and Venturi flow meters. Due to the limitations of their measurement principle, the measurement accuracy of differential pressure flow meters decreases after long-term use. To ensure safe unit operation, a 2% flow measurement uncertainty is considered. To increase the power output of nuclear power units, using high-precision ultrasonic flow meters for main feedwater measurement with a measurement accuracy of up to 0.3% is an effective technical approach and is of great significance for improving the economic efficiency of nuclear power units.

[0003] The development of domestically produced ultrasonic flow meters for main feedwater is in its initial stage. Accurate calculation of their uncertainty is a crucial step in equipment manufacturing verification and ultimately, their applicability to nuclear power units. Existing research indicates that, in many cases, accurate flow measurement uncertainty calculation requires a comprehensive understanding of the velocity profile. Therefore, it is necessary to establish an accuracy testing device for main feedwater flow meters in nuclear power plants. This device should accurately reproduce the fluid velocity field within the actual unit's piping and monitor and maintain a precise and stable flow measurement reference standard to accurately determine the flow meter's accuracy and support subsequent engineering applications.

[0004] The development of domestically produced ultrasonic flow meters for main feedwater is still in its early stages, and its engineering application faces a key bottleneck: how to accurately calculate and verify its flow measurement uncertainty. Reliable uncertainty assessment must be based on a comprehensive understanding of the fluid velocity profile characteristics within the pipeline. Existing testing environments, limited by technical conditions, cannot realistically reproduce the complex flow field dynamics characteristics unique to nuclear power units, characterized by high temperature, high pressure, large flow rate, and complex pipeline layouts. There is a lack of high-precision testing platforms that can simultaneously meet the requirements of actual operating condition simulation and stable flow reference maintenance, thus limiting the accuracy verification and performance optimization of the equipment. This patent innovatively proposes a dedicated accuracy testing device that can highly reproduce the fluid velocity distribution characteristics within actual nuclear power unit pipelines and continuously provide an accurate and stable flow measurement reference. This technical solution will provide a key technical platform for the research, development, testing, calibration, and certification of high-precision flow meters, effectively solving the accuracy testing problem of main feedwater flow meters in nuclear power plants. Summary of the Invention

[0005] The purpose of this invention is to provide a device for testing the accuracy of the main feedwater flow meter in a nuclear power plant. It integrates factors such as fluid generation, flow measurement reference standard, and the accuracy test section of the main feedwater ultrasonic flow meter, and is suitable for the accuracy testing of the main feedwater flow meter in a pressurized water reactor nuclear power unit.

[0006] The technical solution of the present invention is as follows: A closed-loop ultrasonic flow meter accuracy testing device includes a fluid generation module, a flow metering reference module, and a main feedwater flow meter accuracy testing section. The fluid generation module is connected to the flow metering reference module through a pipeline, the flow metering reference module is connected to the main feedwater flow meter accuracy testing section through a pipeline, and the main feedwater flow meter accuracy testing section is connected to the fluid generation module through a pipeline to form a closed loop. The pipelines are all covered with thermal insulation material.

[0007] The fluid generation module includes a main pump, a heat exchanger, a pressure regulator container, a pressure regulator heater, and a pressure regulator cooling water tank. The inlet end of the main pump is connected to the pressure regulator container, the pressure regulator heater is installed inside the pressure regulator container, the pressure regulator container is connected to the pressure regulator cooling pump through a pipe, the pressure regulator cooling pump is connected to the pressure regulator cooling water tank through a pipe, and the outlet end of the main pump is connected to the heat exchanger through a pipe.

[0008] The flow metering reference module includes a first high-precision flow meter, a second high-precision flow meter, a third high-precision flow meter, a fourth high-precision flow meter, a fifth high-precision flow meter, and a sixth high-precision flow meter. The upstream of the first, second, third, and fourth high-precision flow meters are respectively connected to a first valve, a second valve, a third valve, and a fourth valve via pipelines. The first, second, third, and fourth valves are respectively connected to the pipeline at the outlet end of the heat exchanger via pipelines. The first, second, third, and fourth high-precision flow meters are respectively connected to a single pipeline via pipelines and then branch off into two sub-pipelines. One sub-pipeline connects to the fifth high-precision flow meter, and the other sub-pipeline connects to the sixth high-precision flow meter.

[0009] The first high-precision flow meter, the second high-precision flow meter, the third high-precision flow meter, the fourth high-precision flow meter, the fifth high-precision flow meter, and the sixth high-precision flow meter are flow meters with different applicable flow testing ranges.

[0010] The main water supply flow meter accuracy test section includes three parallel pipes.

[0011] One end of each of the three pipes is connected to the outlet of the fifth and sixth high-precision flow meters, and the other end of each of the three pipes is connected to the inlet of the main pump.

[0012] One of the three pipes is equipped with a fifth valve and the first ultrasonic flow meter to be tested, another pipe is equipped with a sixth valve and the second ultrasonic flow meter to be tested, and the third pipe is equipped with a seventh valve and the third ultrasonic flow meter to be tested.

[0013] The beneficial effects of the present invention are: (1) It can reproduce the complex flow velocity field in the main feedwater pipeline of a nuclear power unit in the laboratory, providing a near-real working environment for the flow meter; (2) By establishing a precise measurement benchmark, the main feedwater flow meter can be calibrated with high precision, ensuring the accuracy and reliability of its measurement results, and providing key data support for its engineering application. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of an accuracy testing device for a main feedwater flow meter in a nuclear power plant, provided by the present invention.

[0015] In the diagram, 1 is the main pump; 2 is the heat exchanger; 3 is the first valve; 4 is the second valve; 5 is the third valve; 6 is the fourth valve; 13 is the fifth valve; 14 is the sixth valve; 15 is the seventh valve; 7 is the first high-precision flow meter; 8 is the second high-precision flow meter; 9 is the third high-precision flow meter; 10 is the fourth high-precision flow meter; 11 is the fifth high-precision flow meter; 12 is the sixth high-precision flow meter; 16 is the first ultrasonic flow meter under test; 17 is the second ultrasonic flow meter under test; 18 is the third ultrasonic flow meter under test; 19 is the pressure regulator container; 20 is the pressure regulator heater; 21 is the pressure regulator cooling water tank; and 22 is the pressure regulator cooling pump. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] To achieve accuracy testing of the main feedwater flow meter in nuclear power plants, this invention provides a closed-loop ultrasonic flow meter accuracy testing device, which can effectively simulate the high temperature, high pressure, and high flow conditions of the main feedwater pipeline during the operation of a nuclear power unit, and achieve accurate accuracy testing.

[0018] like Figure 1 As shown, a closed-loop ultrasonic flow meter accuracy testing device includes a fluid generation module, a flow metering reference module, a main feed water flow meter accuracy testing section, and pipes of different sizes connecting each part. All pipes are covered with insulation material.

[0019] The fluid generation module includes a main pump 1, a heat exchanger 2, a pressure regulator container 19, a pressure regulator heater 20, and a pressure regulator cooling water tank 21. The inlet end of the main pump 1 is connected to the pressure regulator container 19, which houses the pressure regulator heater 20. The pressure regulator container 19 is connected to a pressure regulator cooling pump 22 via a pipe, and the pressure regulator cooling pump 22 is connected to the pressure regulator cooling water tank 21 via a pipe. The outlet end of the main pump 1 is connected to the heat exchanger 2 via a pipe. The main pump 1 and the heat exchanger 2 generate the fluid with the required temperature, pressure, and flow rate for the test. The pressure regulator is mainly used for small-scale pressure regulation and stabilization. The system aims to replicate the actual thermal-hydraulic characteristics of the fluid within the unit's piping as closely as possible.

[0020] The flow metering reference module includes certified high-precision flow meters with a relatively low flow measurement range. Among them, the first high-precision flow meter 7, the second high-precision flow meter 8, the third high-precision flow meter 9, the fourth high-precision flow meter 10, the fifth high-precision flow meter 11, and the sixth high-precision flow meter 12 are flow meters with different applicable flow testing ranges. The upstream of the first high-precision flow meter 7, the second high-precision flow meter 8, the third high-precision flow meter 9, and the fourth high-precision flow meter 10 are respectively connected to the first valve 3, the second valve 4, the third valve 5, and the fourth valve 6 via pipelines. The first valve 3, the second valve 4, the third valve 5, and the fourth valve 6 are respectively connected to the pipeline at the outlet end of the heat exchanger 2 via pipelines. The first high-precision flow meter 7, the second high-precision flow meter 8, the third high-precision flow meter 9, and the fourth high-precision flow meter 10 are respectively connected to a single pipeline and then branch off into two sub-pipes. One sub-pipe connects to the fifth high-precision flow meter 11, and the other sub-pipe connects to the sixth high-precision flow meter 12. The distances between each flowmeter and the upstream valve / flow channel direction change points and the downstream flow channel direction change points are sufficient to meet the requirements for accurate measurement. The upstream valves of the flowmeters are opened or closed according to the test requirements to ensure that the flow rate through each flowmeter is within its optimal measurement range and that the flow rate through the test section is the required flow rate. The measurement results from the first high-precision flowmeter 7, the second high-precision flowmeter 8, the third high-precision flowmeter 9, and the fourth high-precision flowmeter 10 are cross-validated with the measurement results from the fifth high-precision flowmeter 11 and the sixth high-precision flowmeter 12 to ensure the reliability of the flow measurement reference standard.

[0021] The main feedwater flow meter accuracy test section consists of three parallel pipes. One end of each pipe is connected to the outlet of the fifth high-precision flow meter 11 and the sixth high-precision flow meter 12, and the other end is connected to the inlet of the main pump 1. One pipe is equipped with the fifth valve 13 and the first ultrasonic flow meter to be tested 16; another pipe is equipped with the sixth valve 14 and the second ultrasonic flow meter to be tested 17; and the third pipe is equipped with the seventh valve 15 and the third ultrasonic flow meter to be tested 18. The pipe dimensions correspond to the main feedwater pipe dimensions of mainstream domestic pressurized water reactor units Hualong One, CNP650, and CNP1000. Valves and ultrasonic flow meters to be tested are arranged on each pipe. To ensure that the fluid passing through the ultrasonic flow meters under test is sufficiently developed to meet the installation requirements, the distance between the flow meters and the upstream valves and the points where the downstream pipe direction changes is sufficient, and the pipes are kept horizontal, consistent with the actual main feedwater pipe installation conditions of the units, to reproduce the fluid velocity field. The valve on the corresponding single pipe is opened according to the testing requirements to start the test.

Claims

1. A closed-loop ultrasonic flowmeter accuracy testing device, characterized in that: It includes a fluid generation module, a flow metering reference module, and a main feedwater flow meter accuracy test section. The fluid generation module is connected to the flow metering reference module through a pipeline, the flow metering reference module is connected to the main feedwater flow meter accuracy test section through a pipeline, and the main feedwater flow meter accuracy test section is connected to the fluid generation module through a pipeline to form a closed loop. All pipelines are covered with thermal insulation material.

2. The closed-loop ultrasonic flowmeter accuracy testing device as described in claim 1, characterized in that: The fluid generation module includes a main pump, a heat exchanger, a pressure regulator container, a pressure regulator heater, and a pressure regulator cooling water tank. The inlet end of the main pump is connected to the pressure regulator container, the pressure regulator heater is installed inside the pressure regulator container, the pressure regulator container is connected to the pressure regulator cooling pump through a pipe, the pressure regulator cooling pump is connected to the pressure regulator cooling water tank through a pipe, and the outlet end of the main pump is connected to the heat exchanger through a pipe.

3. The closed-loop ultrasonic flowmeter accuracy testing device as described in claim 1, characterized in that: The flow metering reference module includes a first high-precision flow meter, a second high-precision flow meter, a third high-precision flow meter, a fourth high-precision flow meter, a fifth high-precision flow meter, and a sixth high-precision flow meter. The upstream of the first, second, third, and fourth high-precision flow meters are respectively connected to a first valve, a second valve, a third valve, and a fourth valve via pipelines. The first, second, third, and fourth valves are respectively connected to the pipeline at the outlet end of the heat exchanger via pipelines. The first, second, third, and fourth high-precision flow meters are respectively connected to a single pipeline via pipelines and then branch off into two sub-pipelines. One sub-pipeline connects to the fifth high-precision flow meter, and the other sub-pipeline connects to the sixth high-precision flow meter.

4. The closed-loop ultrasonic flowmeter accuracy testing device as described in claim 3, characterized in that: The first high-precision flow meter, the second high-precision flow meter, the third high-precision flow meter, the fourth high-precision flow meter, the fifth high-precision flow meter, and the sixth high-precision flow meter are flow meters with different applicable flow testing ranges.

5. The closed-loop ultrasonic flowmeter accuracy testing device as described in claim 1, characterized in that: The main water supply flow meter accuracy test section includes three parallel pipes.

6. The closed-loop ultrasonic flowmeter accuracy testing device as described in claim 5, characterized in that: One end of each of the three pipes is connected to the outlet of the fifth and sixth high-precision flow meters, and the other end of each of the three pipes is connected to the inlet of the main pump.

7. The closed-loop ultrasonic flowmeter accuracy testing device as described in claim 5, characterized in that: One of the three pipes is equipped with a fifth valve and the first ultrasonic flow meter to be tested, another pipe is equipped with a sixth valve and the second ultrasonic flow meter to be tested, and the third pipe is equipped with a seventh valve and the third ultrasonic flow meter to be tested.

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