Water test device for core neutron flux thimble

Abstract

The present disclosure belongs to the technical field of nuclear power and particularly relates to a water pressure test device for a reactor core neutron flux thimble. The present disclosure can simulate the actual working condition of the reactor core neutron flux thimble through the reactor core neutron flux thimble, a pressure gauge, a pressure relief valve, a water pressure test device, a buffer tank and a compressor. The data obtained by the pressure gauge and the measuring cylinder can quickly and accurately analyze the performance of the thimble under the actual working condition, and the present disclosure does not need to disassemble the whole device in which the reactor core neutron flux thimble is installed. The device of the present disclosure can provide a reference for the experimental method and test device required for the water pressure test of the reactor core neutron flux thimble of a nuclear power plant.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power technology, specifically relating to a hydrostatic testing device for a reactor core neutron flux bushing. Background Technology

[0002] The core neutron flux bushing (commonly known as a finger bushing) primarily provides a measurement channel for the core neutron flux measurement probe within the reactor core neutron flux measurement system (RIC). One end of the core neutron flux bushing is sealed with a tapered weld plug inside the reactor pressure vessel, while the other end, located in the core instrumentation area, requires the insertion of a neutron flux detector. Typically, the core neutron flux bushing has an outer diameter of 8.6 mm, an inner diameter of 5.2 mm, a wall thickness of 1.7 mm, and is made of 316 austenitic stainless steel. Because each core neutron flux bushing is located at a different position within the core, its length varies, ranging from 14 to 16 meters. The core neutron flux bushing is a crucial component of the reactor pressure vessel boundary. During unit operation, various forms of failure may occur in the core neutron flux bushing and its conduit sealing sections, potentially affecting core neutron flux measurement or causing primary coolant leakage. Specifically, the seal between the core neutron flux bushing and its conduit is ensured by a high-pressure mechanical seal. The strength of the core neutron flux bushing itself constitutes the pressure boundary. However, if damage occurs along the entire length of the core neutron flux bushing, even if the sealing assembly is intact, reactor coolant can leak from inside the core neutron flux bushing to outside the pressure vessel, leading to primary circuit pressure boundary failure and radioactive contamination. Therefore, regular inspection, maintenance, and replacement of the core neutron flux bushing are necessary. For a long time, domestic practices for core neutron flux bushing maintenance and replacement have followed those of foreign technical providers. However, the related operation and measurement methods are cumbersome, and the entire device usually needs to be disassembled during installation and maintenance. Therefore, there is an urgent need to improve the relevant operations to overcome the above problems. Summary of the Invention

[0003] To overcome the problems existing in related technologies, a hydrostatic testing device for a reactor core neutron flux sleeve is provided. The device includes: a reactor core neutron flux sleeve, a pressure gauge, a pressure relief valve, a hydrostatic testing device, a buffer tank, and a compressor. The core neutron flux sleeve is fixedly connected to the hydrostatic testing device to form a hollow test assembly, so that the core neutron flux sleeve is consistent with the water pressure inside the hydrostatic testing device; The compressor, buffer tank, and test assembly are connected in series via connecting pipes. The compressor's water inlet is connected to a water source via a device water injection valve. A compressor water injection valve is installed between the compressor's output and the buffer tank's water inlet. A shut-off valve and a pressure gauge are installed between the buffer tank's output and the test assembly. The pressure gauge is used to detect the water pressure inside the test assembly. The measuring cylinder is vertically positioned. The bottom of the measuring cylinder is connected to the pipe between the device water injection valve and the compressor via a first measuring pipe. A compressor water inlet valve is installed on the first measuring pipe. The bottom of the measuring cylinder is also connected to the pipe between the buffer pipe and the shut-off valve via a second measuring pipe. A measuring cylinder water injection valve is installed on the second measuring pipe. The water pressure test device is connected to a drainage system via a drain pipe. A pressure relief valve is installed on the drain pipe.

[0004] In one possible implementation, the apparatus of this disclosure is operated to perform a pressure test using the following steps: Step 1: Open the pressure relief valve, shut-off valve, measuring cylinder water injection valve, compressor water injection valve, compressor inlet valve, and device water injection valve, and continue to inject water until all components and pipelines in the device are filled with water; Step 2: After step 1, close the pressure relief valve, turn on the compressor, raise the pressure to the preset pressure value, and then turn off the compressor. Open the pressure relief valve to remove air from the pipeline and the test piece. Step 3: After step 2, open the pressure relief valve. When the pressure gauge shows a pressure of 0, close the pressure relief valve and add water to the preset scale mark on the measuring cylinder. Step 4: After step 3, open the shut-off valve, measuring cylinder water injection valve, compressor water injection valve, and compressor inlet valve, close the pressure relief valve and device water injection valve, and then turn on the compressor to gradually increase the pressure inside the device from low to high to multiple preset pressure values. Record the increase in water volume at each pressure value by the change in the measuring cylinder water level reading, and the scale values ​​at each pressure value form a loading curve. Step 5: By switching the water injection valve on the measuring cylinder, the pressure of the device is gradually reduced from high to low. During unloading, if the water level in the measuring cylinder rises, the water injection valve is opened to release water into the empty measuring cylinder until the water level is adjusted to the preset scale mark on the measuring cylinder. The amount of water released each time is recorded to create an unloading curve. When the pressure of the device reaches the water pressure test pressure of the core neutron flux sleeve, the pressure is maintained for a preset time. If the core neutron flux sleeve shows no obvious deformation and the pressure gauge does not drop, the core neutron flux sleeve pressure test is qualified.

[0005] In one possible implementation, the hydrostatic test of the reactor core neutron flux sleeve is achieved by comparing the values ​​of the total water added and the total water released.

[0006] In one possible implementation, step 2 is repeated multiple times before step 3.

[0007] In one possible implementation, in step 5, the preset duration is 10 to 30 minutes when the pressure of the device reaches the hydrostatic test pressure of the core neutron flux bushing.

[0008] In one possible implementation, multiple preset pressure values ​​are 5 MPa, 10 MPa, 15 MPa, 20 MPa, 25 MPa, and 25.8 MPa.

[0009] The beneficial effects of this disclosure are as follows: This disclosure can simulate the actual working conditions of the core neutron flux bushing through the core neutron flux bushing, pressure gauge, pressure relief valve, hydrostatic testing device, buffer tank, and compressor. The data obtained by the pressure gauge, measuring cylinder, and other devices of this invention can quickly and accurately analyze the device performance of the bushing under actual working conditions without the need to dismantle the entire set of devices installed on the core neutron flux bushing. The device disclosed in this invention can provide a reference for the experimental methods and testing devices required for hydrostatic testing of the core neutron flux bushing in nuclear power plants. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of a hydrostatic test apparatus for a reactor core neutron flux sleeve, as shown in an embodiment of this disclosure.

[0011] In the picture: 1. Core neutron flux sleeve; 2. Connecting pipe; 3. Pressure gauge; 4. Pressure relief valve; 5. Hydrostatic testing device; 6. Buffer tank; 7. Shut-off valve; 8. Measuring cylinder water inlet valve; 9. Compressor water inlet valve; 10. Measuring cylinder; 11. Compressor inlet valve; 12. Unit water injection valve; 13. Compressor Detailed Implementation

[0012] The present disclosure will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0013] Unless otherwise defined, the technical and scientific terms used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains; the terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure; the term "comprising" and any variations thereof in this disclosure are intended to cover non-exclusive inclusion. Clearly, the embodiments described in this disclosure are only a part of the embodiments of this disclosure, and not all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this disclosure without inventive effort are within the scope of protection of this disclosure.

[0014] In this disclosure, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0015] Figure 1 This is a schematic diagram of a hydrostatic testing device for a reactor core neutron flux sleeve, as shown in an embodiment of this disclosure. Figure 1 As shown, the device includes: a core neutron flux sleeve 1, a pressure gauge 3, a pressure relief valve 4, a hydrostatic testing device 5, a buffer tank 6, and a compressor 13.

[0016] The core neutron flux sleeve 1 is fixedly connected to the hydrostatic testing device 5 to form a hollow test assembly (for example, the core neutron flux sleeve 1 and the hydrostatic testing device 5 can be fixedly connected by a flange), so that the water pressure inside the core neutron flux sleeve 1 is consistent with that inside the hydrostatic testing device 5. Experimental data is obtained by measuring the water pressure in the core neutron flux sleeve 1. The compressor 13, the buffer tank 6, and the test assembly are connected in series sequentially through the connecting pipe 2. The water inlet of the compressor 13 is connected to the water source through the device water injection valve 12. A compressor injection valve is installed between the output end of the compressor 13 and the water inlet end of the buffer tank 6. A shut-off valve 7 and a pressure gauge 3 are installed between the output end of the water valve 9 and the buffer tank 6 and the test assembly. The pressure gauge 3 is used to detect the water pressure in the test assembly. The measuring cylinder 10 is set vertically. The bottom end of the measuring cylinder 10 is connected to the pipeline between the device water injection valve 12 and the compressor 13 through the first measuring pipeline. The compressor water inlet valve 11 is installed on the first measuring pipeline. The bottom end of the measuring cylinder 10 is also connected to the pipeline between the buffer pipe 6 and the shut-off valve 7 through the second measuring pipeline. The measuring cylinder water injection valve 8 is installed on the second measuring pipeline. The water pressure test device 5 is connected to the drainage system through the drain pipe. The pressure relief valve 4 is installed on the drain pipe.

[0017] In one possible implementation, the apparatus of this disclosure is operated to perform a pressure test using the following steps: Step 1: Open pressure relief valve 4, shut-off valve 7, measuring cylinder water injection valve 8, compressor water injection valve 9, compressor water inlet valve 11, and device water injection valve 12. Continue to inject water until all components and pipelines in the device are filled with water. Step 2: After step 1, close the pressure relief valve 4, turn on the compressor 13, raise the pressure to the preset pressure value (e.g., 1 MPa), then turn off the compressor 13. Open the pressure relief valve 4 to purge the air from the device's pipeline and the test specimen. Repeat step 2 several times to ensure that the air in the device is fully purged.

[0018] Step 3: After step 2, open the pressure relief valve 4. When the pressure gauge 3 shows a pressure of 0, close the pressure relief valve 4 and add water to the preset scale mark on the measuring cylinder 10.

[0019] Step 4: After step 3, open the shut-off valve 7, measuring cylinder water injection valve 8, compressor water injection valve 9, and compressor inlet valve 11. Close the pressure relief valve 4 and device water injection valve 12. Then, turn on the compressor 13 to gradually increase the pressure inside the device from low to high to multiple preset pressure values ​​(the multiple preset pressure values ​​can be 5 MPa, 10 MPa, 15 MPa, 20 MPa, 25 MPa, and 25.8 MPa). Record the increase in water volume at each pressure value by the change in the water level reading of the measuring cylinder 10. The scale values ​​at each pressure value form a loading curve. This loading curve can clearly describe the relationship between the pressure and the expansion volume of the core neutron flux sleeve 1. When the pressure of the device reaches the hydrostatic test pressure of the core neutron flux sleeve 1 (25.8 MPa), maintain the pressure for 10-30 minutes. If the core neutron flux sleeve 1 shows no obvious deformation and the pressure gauge 3 does not drop, the pressure test is complete. Step 5: By switching the water injection valve 8 on the measuring cylinder, the pressure of the device is gradually reduced from high to low (for example, in sequence at 25MPa, 20MPa, 15MPa, 10MPa, 5MPa, 1MPa, and 0MPa). During unloading, if the water level in the measuring cylinder 10 rises, the water injection valve 12 is opened to release water into the empty measuring cylinder until the water level is adjusted to the mark on the measuring cylinder 10. The amount of water released each time is recorded to create an unloading curve.

[0020] Finally, the hydrostatic test of the reactor core neutron flux sleeve 1 was achieved by comparing the total water added and the total water released.

[0021] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A hydrostatic testing device for a reactor core neutron flux sleeve, characterized in that, The device includes: a core neutron flux sleeve, a pressure gauge, a pressure relief valve, a hydrostatic testing device, a buffer tank, and a compressor; The core neutron flux sleeve is fixedly connected to the hydrostatic testing device to form a hollow test assembly, so that the core neutron flux sleeve is consistent with the water pressure inside the hydrostatic testing device; The compressor, buffer tank, and test assembly are connected in series via connecting pipes. The compressor's water inlet is connected to a water source via a device water injection valve. A compressor water injection valve is installed between the compressor's output and the buffer tank's water inlet. A shut-off valve and a pressure gauge are installed between the buffer tank's output and the test assembly. The pressure gauge is used to detect the water pressure inside the test assembly. The measuring cylinder is vertically positioned. The bottom of the measuring cylinder is connected to the pipe between the device water injection valve and the compressor via a first measuring pipe. A compressor water inlet valve is installed on the first measuring pipe. The bottom of the measuring cylinder is also connected to the pipe between the buffer pipe and the shut-off valve via a second measuring pipe. A measuring cylinder water injection valve is installed on the second measuring pipe. The water pressure test device is connected to a drainage system via a drain pipe. A pressure relief valve is installed on the drain pipe.

2. The apparatus according to claim 1, characterized in that, The apparatus of this disclosure is operated to perform a pressure test using the following steps: Step 1: Open the pressure relief valve, shut-off valve, measuring cylinder water injection valve, compressor water injection valve, compressor inlet valve, and device water injection valve, and continue to inject water until all components and pipelines in the device are filled with water; Step 2: After step 1, close the pressure relief valve, turn on the compressor, raise the pressure to the preset pressure value, and then turn off the compressor. Open the pressure relief valve to remove air from the pipeline and the test piece. Step 3: After step 2, open the pressure relief valve. When the pressure gauge shows a pressure of 0, close the pressure relief valve and add water to the preset scale mark on the measuring cylinder. Step 4: After step 3, open the shut-off valve, measuring cylinder water injection valve, compressor water injection valve, and compressor inlet valve, close the pressure relief valve and device water injection valve, and then turn on the compressor to gradually increase the pressure inside the device from low to high to multiple preset pressure values. Record the increase in water volume at each pressure value by the change in the measuring cylinder water level reading, and the scale values ​​at each pressure value form a loading curve. Step 5: By switching the water injection valve on the measuring cylinder, the pressure of the device is gradually reduced from high to low. During unloading, if the water level in the measuring cylinder rises, the water injection valve is opened to release water into the empty measuring cylinder until the water level is adjusted to the preset scale mark on the measuring cylinder. The amount of water released each time is recorded to create an unloading curve. When the pressure of the device reaches the water pressure test pressure of the core neutron flux sleeve, the pressure is maintained for a preset time. If the core neutron flux sleeve shows no obvious deformation and the pressure gauge does not drop, the core neutron flux sleeve pressure test is qualified.

3. The apparatus according to claim 1, characterized in that, The hydrostatic test of the reactor core neutron flux sleeve was achieved by comparing the total water added and the total water released.

4. The apparatus according to claim 1, characterized in that, Repeat step 2 several times before step 3.

5. The apparatus according to claim 1, characterized in that, In step 5, the preset duration is 10 to 30 minutes when the pressure of the device reaches the hydrostatic test pressure of the core neutron flux bushing.

6. The apparatus according to claim 1, characterized in that, Multiple preset pressure values ​​are 5 MPa, 10 MPa, 15 MPa, 20 MPa, 25 MPa, and 25.8 MPa.

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