A neutron flux tube inspection integrated device

Abstract

The present invention relates to the field of nuclear power plant maintenance technology, and specifically to an integrated device suitable for the overall water pressure test and helium inspection of a neutron flux tube of a nuclear reactor. After the neutron flux tube spare parts are prepared, a leak detection device is designed for the needs of water pressure test and non-destructive testing to provide support for spare parts quality inspection. In the present invention, the helium leak detector and the helium leak detection connection device are connected by a bellows buckle, the neutron flux tube and the helium leak detection device are connected, the handle end is fixed to the sealing section of the middle body, and the sealing section of the middle body is bolted to the sealing ball valve; when in the helium leak detection state, the neutron flux tube outer wall helium filling device is connected to the sealing ball valve through a horizontal stop valve, and the pressure gauge is connected to the sealing ball valve through a vertical stop valve; when in the water pressure test state, the water pressure booster pump is connected to the sealing ball valve through the horizontal stop valve. The present invention not only improves efficiency and saves costs, but also can better achieve the purpose of leak detection.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear power plant maintenance, and in particular to an integrated device suitable for an integral water pressure test and helium inspection of a neutron flux tube of a nuclear reactor. Background Art

[0002] Reactor neutron flux tubes in pressurized water reactor nuclear power plants, commonly known as casing tubes, are one of the key equipment in pressurized water reactor nuclear power plants. The number of neutron flux tubes varies with the size of the reactor. The number of neutron flux tubes in a single unit of a conventional reactor is 20 to 50. As the measurement channel for the neutron flux in the core nuclear measurement system, the neutron flux tubes are evenly distributed in the core fuel assembly channel, penetrate the fuel assembly, and are exposed in the core. The neutron flux tube is a primary pressure boundary. Mechanical wear caused by radiation embrittlement and flow-induced vibration will cause the tube wall to become thinner or even damaged, which will cause leakage and contamination of the primary coolant.

[0003] Taking a 1000MWe nuclear power plant as an example, a single unit has 50 neutron flux tubes, with lengths ranging from 13 to 18 meters. Based on domestic and foreign experience feedback, due to the large amount of primary coolant in a 1000MWe nuclear power plant and the complex thermal hydraulic characteristics, neutron flux tube replacement has been widely carried out, and there is a strong demand for neutron flux tube spare parts.

[0004] Since each neutron flux tube has a different length, nuclear power plants cannot reserve spare parts for each neutron flux tube. Instead, they reserve spare parts according to the longest size. When the spare parts are used, they are prepared according to the actual length of the neutron flux tube to be replaced. The preparation of neutron flux tube spare parts involves cutting, groove grinding, welding, and water pressure testing and non-destructive testing of neutron flux tubes after preparation. Domestic nuclear power plants have produced a series of scientific and technological innovations in the original development of neutron flux tube spare parts preparation technology.

[0005] After the neutron flux tube spare parts are prepared, each spare part needs to be subjected to a hydrostatic test and non-destructive testing to ensure that the quality of the neutron flux tube spare parts meets the requirements through final inspection. In order to meet the needs of hydrostatic testing and non-destructive testing, a set of integrated hydrostatic testing and helium inspection equipment for nuclear reactor neutron flux tubes is designed and manufactured to provide support for spare parts quality inspection. Summary of the invention

[0006] The technical problem solved by the present invention is:

[0007] Reactor neutron flux tube is the primary pressure boundary of nuclear reactor and one of the key equipment of reactor core. It directly bears the high temperature and high pressure environment of nuclear reactor. Its reliable sealing is an inevitable requirement for nuclear safety. At present, the preparation of neutron flux tube spare parts has long been monopolized by foreign technology. Domestic nuclear power plants do not have the technical ability to prepare neutron flux tube spare parts, nor do they have corresponding inspection equipment. To inspect the prepared neutron flux tube spare parts, a water pressure test device that can simulate the pressure of nuclear reactor core and a device for helium tightness inspection are required.

[0008] The technical solution of the present invention is:

[0009] Based on the longest neutron flux tube length, an integrated device that can be used for both water pressure test and helium leak detection is designed and manufactured. The main body of the device consists of three parts: a water pressure test connection device, an intermediate body, and a helium leak detection device. The structure and function of each part are introduced as follows:

[0010] An integrated device for hydrostatic test and helium inspection of a nuclear reactor neutron flux tube comprises: a helium leak detector, a helium leak detection device, a sealing ball valve, a helium filling device for the outer wall of the neutron flux tube, a water pressure booster pump, and a pressure gauge. The helium leak detector and the helium leak detection device are connected by a bellows buckle, the neutron flux tube and the helium leak detection device are connected, the handle end is fixed to the sealing section of the middle body, and the sealing section of the middle body is bolted to the sealing ball valve; when in the helium leak detection state, the helium filling device for the outer wall of the neutron flux tube is connected to the sealing ball valve through a horizontal stop valve, and the pressure gauge is connected to the sealing ball valve through a vertical stop valve; when in the hydrostatic test state, the water pressure booster pump is connected to the sealing ball valve through the horizontal stop valve.

[0011] The helium leak detection device includes: a helium calibration leak, an exhaust vacuum pump, an exhaust isolation valve, and a verification isolation valve, wherein the exhaust isolation valve is connected to the exhaust vacuum pump, and the verification isolation valve is connected to the helium calibration leak. The helium leak detection device also includes a vacuum gauge, which is fixedly mounted on the helium leak detection device.

[0012] The right connecting pipe of the helium leak detection device is divided into an inner pipe and an outer pipe, wherein the outer diameter of the inner pipe is 3mm, which is smaller than the inner diameter of the neutron flux tube; the outer pipe is connected to the handle section of the neutron flux tube. The stop valve is in a closed state when maintaining pressure.

[0013] The middle body is a stainless steel seamless steel pipe. The length, material and thickness of the middle body are consistent with those of the neutron flux tube used.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The integrated device has a simple structure and high interface sealing performance. It can withstand 30MPa high pressure and meet the helium sealing requirements.

[0016] The integrated device has an interface connected to the water pressure test device, which can carry out the neutron flux tube water pressure test;

[0017] The integrated device has an interface connected to the helium inspection device, which can perform neutron flux tube helium inspection;

[0018] The integrated device can realize the overall pressurization, leak detection and sealing component performance inspection of the neutron flux tube;

[0019] 5) The integrated device can realize the overall pressurization and leak detection of neutron flux tubes of different lengths. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Helium inspection device structure diagram

[0021] Figure 2 Helium leak detection device structure diagram

[0022] Figure 3 Structure diagram of water pressure test device

[0023] In the figure: 1. Helium leak detector; 2. Helium calibration leak hole; 3. Air extraction vacuum pump; 4. Helium leak detection device; 5. Vacuum gauge; 6. Neutron flux tube; 7. Sealing section; 8. Sealing ball valve; 9. Helium filling device for the outer wall of neutron flux tube; 10. Air extraction isolation valve; 11. Verification isolation valve; 12. Water pressure booster pump; 13. Pressure gauge; 14. Connecting pipe; 15. Vertical stop valve; 16. Horizontal stop valve. DETAILED DESCRIPTION

[0024] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments:

[0025] like Figure 1 , Figure 2 , Figure 3 As shown, a nuclear reactor neutron flux tube integral water pressure test and helium inspection integrated device comprises: a helium leak detector 1, a helium leak detection device 4, a sealing ball valve 8, a neutron flux tube outer wall helium filling device 9, a water pressure booster pump 12, and a pressure gauge 13. The helium leak detector 1 and the helium leak detection device 4 are connected by a bellows buckle, the neutron flux tube 6 is connected to the helium leak detection device 4, the handle end thereof is fixed to the sealing section 7 of the middle body, and the sealing section 7 of the middle body is bolted to the sealing ball valve 8; when in the helium leak detection state, the neutron flux tube outer wall helium filling device 9 is connected to the sealing ball valve 8 through the horizontal stop valve 16, and the pressure gauge 13 is connected to the sealing ball valve 8 through the vertical stop valve 15; when in the water pressure test state, the water pressure booster pump 12 is connected to the sealing ball valve 8 through the horizontal stop valve 16.

[0026] The helium leak detection device 4 comprises: a helium calibration leak hole 2, an exhaust vacuum pump 3, an exhaust isolation valve 10, and a verification isolation valve 11, wherein the exhaust isolation valve 10 is connected to the exhaust vacuum pump 3, and the verification isolation valve 11 is connected to the helium calibration leak hole 2. The helium leak detection device 4 also comprises a vacuum gauge 5, which is fixedly mounted on the helium leak detection device.

[0027] The right connecting pipe 14 of the helium leak detection device 4 is divided into an inner pipe and an outer pipe, wherein the outer diameter of the inner pipe is 3 mm, which is smaller than the inner diameter of the neutron flux tube; the outer pipe is connected to the handle section of the neutron flux tube 6. The stop valve 16 is in a closed state when maintaining pressure.

[0028] The sealing section of the middle body is a stainless steel seamless steel pipe. The length, material and thickness of the sealing section of the middle body are consistent with those of the neutron flux tube used.

[0029] like Figure 3 As shown, the hydraulic test connection device: The hydraulic test device is a connection device used to connect the hydraulic test pump to the main body of the integrated device, which consists of a water filling isolation valve, an exhaust isolation valve and a connection joint. Connect the hydraulic test connection device to the intermediate body, and the helium leak detection device does not need to be connected. The neutron flux tube is installed in the intermediate body, and its handle end is fixed in the sealing section of the intermediate body. The upstream and downstream nuts of the sealing section are tightened according to the torque requirements; the hydraulic test pump is connected to the hydraulic test connection device; the pressure gauge is installed in the pressure gauge interface position of the intermediate body. After the hydraulic test device is connected, water filling, exhaust, pressurization, pressure maintenance, and result inspection can be carried out according to the hydraulic test procedure.

[0030] Intermediate body: The main body is composed of a stainless steel seamless steel pipe (simulating the guide tube of the neutron flux tube), a pressure gauge interface, and a neutron flux tube sealing section.

[0031] The main body is the core part of the integrated device, which has sufficient sealing and pressure-bearing capabilities. The pressure gauge interface is used to install the pressure gauge for the water pressure test, and the neutron flux tube sealing section is used to seal the neutron flux tube to form a water pressure test boundary.

[0032] like Figure 2As shown, the helium leak detection device: The helium leak detection device consists of an exhaust isolation valve, a calibration isolation valve, a vacuum gauge interface, a neutron flux tube handle connection interface, and a helium mass spectrometer connection interface. The water pressure test connection device and the helium leak detection device are connected to the intermediate body, and the isolation valve of the water pressure test connection device is closed. The neutron flux tube is installed in the intermediate body, and its handle end is fixed in the sealing section of the intermediate body. The upstream and downstream nuts of the sealing section are tightened according to the torque requirements; the helium mass spectrometer is connected to the helium leak detection device; the vacuum gauge is installed in the vacuum gauge interface of the helium leak detection device. After the helium inspection device is connected, it can be inflated, pressurized, exhausted, inspected, and calibrated according to the helium inspection procedure. The helium leak detection device can realize functions such as exhaust, calibration, and vacuum display.

[0033] Performance test of sealing components: connect the water pressure test connection device and the helium leak detection device to the intermediate body, install the neutron flux tube sealing component that needs to be tested for performance into the sealing section, and then the sealing performance of the sealing component can be tested by water pressure test and helium inspection.

[0034] The integrated device has the following features:

[0035] The integrated device is equipped with a water pressure test interface at one end and a helium inspection interface at the other end. It is a dual-purpose device that can be used for both overall pressure testing and helium inspection.

[0036] The integrated device interface adopts threaded and quick-connect form, which is convenient for the installation of water pressure test device and helium inspection device.

[0037] The length of the integrated device is set according to the longest neutron flux tube, and the material and thickness refer to the guide tube size of the neutron flux tube.

[0038] The steel pipe used in the integrated device is a stainless steel seamless pipe, and the material and specification are determined by referring to the guide pipe of the neutron flux tube.

[0039] Beneficial effects of the present invention:

[0040] The invention discloses an integrated device for the overall water pressure test and helium inspection of a nuclear reactor neutron flux tube, which has a simple structure and high interface sealing performance, can withstand a high pressure of 30MPa, and can also meet the helium sealing requirements; the device has an interface connected to a water pressure test device, and can perform a water pressure test on the neutron flux tube; at the same time, the device also has an interface connected to a helium inspection device, and can perform a helium inspection on the neutron flux tube; the device can be used to realize the overall pressure testing, leak detection, and sealing component performance inspection requirements of neutron flux tubes of different lengths; not only the efficiency is improved and the cost is saved, but also the purpose of leak detection can be better achieved.

Claims

1. A neutron flux tube inspection integrated device, comprising: A helium leak detector (1), a helium leak detection device (4), a sealing ball valve (8), a neutron flux tube outer wall helium filling device (9), a water pressure booster pump (12), and a pressure gauge (13), characterized in that: the helium leak detector (1) and the helium leak detection device (4) are connected by a bellows buckle, the neutron flux tube (6) and the helium leak detection device (4) are connected, the handle end is fixed to the sealing section (7) of the middle body, and the sealing section (7) of the middle body and the sealing ball valve (8) are bolted; when in the helium leak detection state, the neutron flux tube outer wall helium filling device (9) is connected to the sealing ball valve (8) through the stop valve (16), and the pressure gauge (13) is connected to the sealing ball valve (8) through the stop valve (15); when in the water pressure test state, the water pressure booster pump (12) is connected to the sealing ball valve (8) through the stop valve (16); The helium leak detection device (4) comprises: a helium calibration leak hole (2), an exhaust vacuum pump (3), an exhaust isolation valve (10), and a calibration isolation valve (11), wherein the exhaust isolation valve (10) is connected to the exhaust vacuum pump (3), and the calibration isolation valve (11) is connected to the helium calibration leak hole (2).

2. The integrated neutron flux tube inspection device according to claim 1, characterized in that: The right connecting tube (14) of the helium leak detection device (4) is divided into an inner tube and an outer tube, wherein the outer diameter of the inner tube is 3 mm, which is smaller than the inner diameter of the neutron flux tube; and the outer tube is connected to the handle section of the neutron flux tube (6).

3. The integrated neutron flux tube inspection device according to claim 1, characterized in that: The stop valve (16) is in a closed state when maintaining pressure.

4. The integrated neutron flux tube inspection device according to claim 1, characterized in that: The sealing section (7) of the middle body is a stainless steel seamless pipe.

5. The integrated neutron flux tube inspection device according to claim 1, characterized in that: The helium leak detection device (4) further comprises a vacuum gauge (5), wherein the vacuum gauge (5) is fixedly mounted on the helium leak detection device.

6. The integrated neutron flux tube inspection device according to claim 4, characterized in that: The length, material and thickness of the sealing section (7) of the intermediate body are consistent with those of the neutron flux tube (6) used.

Images