Integrated compact small reactor containment vessel liquid level measuring system and method

Abstract

The invention provides an integrated compact small reactor containment vessel liquid level measuring system and method, and belongs to the technical field of containment vessel liquid level measurement, the integrated compact small reactor containment vessel liquid level measuring system comprises a remote transmission diaphragm capsule, a capillary tube and a transmitter body, the remote transmission diaphragm capsule is arranged in a containment vessel, the transmitter body is arranged outside the containment vessel, and the capillary tube is arranged in the remote transmission diaphragm capsule. The transmitter body is connected with the remote transmission diaphragm capsule through a capillary tube; the teletransmission diaphragm capsule comprises a first teletransmission diaphragm capsule and a second teletransmission diaphragm capsule; the first teletransmission diaphragm capsule and the second teletransmission diaphragm capsule are respectively fixed on the inner wall of the containment through a mounting bracket. According to the invention, the liquid level measurement of the integrated compact small reactor can be realized, and meanwhile, the liquid level measurement instrument can be periodically verified outside the containment, so that the convenience of regular maintenance is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of reactor containment liquid level measurement, and in particular relates to an integrated compact small reactor containment liquid level measurement system and method. Background Art

[0002] In order to monitor and provide continuous level indication and alarm within the range of reactor pressure vessel chamber to maximum containment submergence level during flooding conditions after a nuclear power plant accident, so that operators can understand the status parameters of the nuclear power plant for evaluation and treatment, pressurized water reactor nuclear power plants are equipped with containment level measuring instruments. In traditional large pressurized water reactor nuclear power plants, the containment level is usually measured by a nuclear-grade magnetic float level gauge. The nuclear-grade magnetic float level gauge is generally composed of multiple bypass pipes, reed chain assemblies, magnetic floats, and transmitter electronic components. The reed chain assembly and magnetic float are installed in the bypass pipe. As a primary instrument, it is installed in the containment. The normal ambient temperature it withstands for a long time generally does not exceed 50°C, and it can withstand the design benchmark accident ambient temperature of a nuclear power plant with a peak value of more than 200°C. The transmitter is installed outside the containment as a secondary instrument, without having to experience the harsh environmental conditions under the design benchmark accident.

[0003] An integrated compact small reactor refers to an integrated small reactor (usually with an electrical power of less than 300MW). By designing the core, pressurizer, heat exchanger and related pipeline and valve components inside the pressure vessel, it has the advantages of compact structure, high safety, good economy and application flexibility.

[0004] In an integrated compact small reactor, since the normal operating temperature in the containment is kept at around 200°C for a long time and the space is compact, extremely high requirements are placed on the instruments used to measure the liquid level in the containment, including long-term high temperature resistance, high radiation resistance and miniaturization. The nuclear-grade magnetic float level gauge used in traditional large pressurized water reactor nuclear power plants is difficult to meet the requirement of long-term tolerance of ambient temperatures around 200°C, and its size is usually large, which is not conducive to installation in the containment of a compact small reactor.

[0005] In addition, the liquid level measuring instruments in the containment need to be calibrated regularly to ensure the accuracy of the measuring structure. However, due to the compact space of the integrated compact small reactor, it is difficult to calibrate the liquid level measuring instruments in the containment, which seriously affects the efficiency of regular maintenance. Summary of the invention

[0006] In view of the defects or shortcomings in the prior art, the present invention provides an integrated compact small reactor containment liquid level measurement system and method, which can realize the liquid level measurement of the integrated compact small reactor. At the same time, the liquid level measuring instrument can be regularly calibrated outside the containment, thereby improving the convenience of regular maintenance.

[0007] To achieve the above object, the present invention adopts the following technical solution: In a first aspect, an embodiment of the present invention provides an integrated compact small reactor containment liquid level measurement system, comprising a remote transmission diaphragm box, a capillary tube and a transmitter body, wherein the remote transmission diaphragm box is arranged inside the containment, the transmitter body is arranged outside the containment, and the transmitter body and the remote transmission diaphragm box are connected through a capillary tube; The remote transmission membrane box comprises a first remote transmission membrane box and a second remote transmission membrane box, and the first remote transmission membrane box and the second remote transmission membrane box are respectively fixed on the inner wall of the containment shell through mounting brackets.

[0008] Furthermore, the capillary is filled with a filling liquid, and the filling liquid can withstand long-term high temperature.

[0009] Furthermore, a containment shell penetration piece is arranged on the containment shell, the containment shell penetration piece is arranged horizontally, both ends of the containment shell penetration piece are arranged to penetrate the containment shell, and the capillaries inside and outside the containment shell are connected through the containment shell penetration piece.

[0010] Furthermore, welding joints are provided on the capillaries on both sides of the containment, welding interfaces are provided on the end faces of both ends of the containment penetration piece, and the welding joints at the ends of the capillaries are welded and fixed to the welding interfaces on the end faces of the containment penetration piece.

[0011] Furthermore, a calibration pipeline is provided, the calibration pipeline comprises a first pipeline and a second pipeline, the first pipeline is provided with two, the two first pipelines are respectively connected to the first remote transmission membrane box and the second remote transmission membrane box, and the second pipeline is connected to the first pipeline.

[0012] Furthermore, a first valve is arranged on the first pipeline, and the first valve is an electrically controlled valve connected to a controller arranged outside the containment vessel.

[0013] Furthermore, one end of the second pipeline is connected to the first pipeline between the first valve and the remote transmission membrane box, and the other end passes through the containment shell and extends to the outside of the containment shell. A second valve is arranged on the second pipeline outside the containment shell.

[0014] Furthermore, one end of the second pipeline away from the first pipeline is connected to a pressure checking device, and the pressure checking device is detachably connected to the second pipeline.

[0015] In a second aspect, an embodiment of the present invention further provides an integrated compact small reactor containment liquid level measurement method, using an integrated compact small reactor containment liquid level measurement system as described above, comprising the following steps: Under accident conditions, when cooling water exists in the containment, the first remote transmission diaphragm box and the second remote transmission diaphragm box respectively sense the liquid pressure at different heights, and transmit the liquid pressure to the transmitter body through the capillary. The transmitter body obtains the pressure difference measured by the first remote transmission diaphragm box and the second remote transmission diaphragm box in the containment according to the received liquid pressure, and calculates the liquid level of the containment according to the pressure difference.

[0016] Furthermore, when it is necessary to calibrate the accuracy of the transmitter body, close the first valve, open the second valve, connect the pressure calibration device to the second pipeline, and the pressure output by the pressure calibration device is transmitted to the remote transmission diaphragm box through the second pipeline, and is transmitted to the transmitter body through the capillary. By reading the output of the remote transmission transmitter body, the accuracy of the transmitter body is determined and calibrated as needed.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention arranges a remote transmission diaphragm box in the containment and connects it to a transmitter body arranged outside the containment through a capillary tube. The remote transmission diaphragm box senses the liquid pressure in the containment and transmits it to the transmitter body. The transmitter body calculates the liquid level in the containment. Compared with the traditional containment liquid level measurement system, it occupies less space, so that it can be used in an integrated compact small reactor to realize the liquid level measurement of the integrated compact small reactor.

[0018] 2. The remote transmission membrane box in the present invention is made of high-temperature metal material, and the capillary is filled with high-temperature resistant filling liquid, which can cope with the harsh environment of the compact small reactor containment with a long-term ambient temperature of more than 200°C and an accident peak temperature of more than 300°C, and realize accurate measurement of the liquid level of the small reactor containment. Through the reasonable selection of materials such as radiation-resistant filling liquid, it can cope with 10 5 Gy or above high radiation environment.

[0019] 3. The present invention arranges a containment penetration piece on the containment, and connects the capillaries inside and outside the containment through the containment penetration piece, thereby ensuring the integrity and sealing of the containment.

[0020] 4. The present invention provides a calibration pipeline, thereby allowing operation and maintenance personnel to perform regular calibration of the liquid level measuring instrument outside the containment, thereby improving the convenience of regular maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is an overall structural diagram of a liquid level measurement system in Embodiment 1 of the present invention; Figure 2 This is a diagram showing the connection relationship between the containment penetration piece and the capillary tube in the first embodiment of the present invention; Figure 3 This is a diagram showing the connection relationship between another containment penetration piece and a capillary tube in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the calibration pipeline structure in the first embodiment of the present invention; Figure 5 This is a flow chart of transmitter accuracy verification in Embodiment 2 of the present invention; Among them, 1. transmitter body; 2. capillary; 3. containment; 4. first remote transmission diaphragm box; 5. second remote transmission diaphragm box; 6. containment penetration; 7. first pipeline; 8. second pipeline; 9. first valve; 10. second valve; 11. pressure calibration device. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0023] Embodiment 1 A typical implementation of the present invention is as follows Figure 1 As shown, an integrated compact small reactor containment liquid level measurement system includes a remote transmission diaphragm box, a capillary tube 2 and a transmitter body 1. The remote transmission diaphragm box is arranged inside the containment 3 to withstand long-term high temperature environment and high radiation environment. The transmitter body 1 is arranged outside the containment 3 to withstand normal temperature environment and low radiation environment. The transmitter body 1 and the remote transmission diaphragm box are connected through the capillary tube 2. During normal operation or in the event of an accident, the remote transmission transmitter system composed of the remote transmission diaphragm box, the capillary tube 2 and the transmitter body 1 is not connected to the reactor coolant pipeline, and the pipeline is not connected to the containment atmosphere, forming a closed loop. There is no need to set an isolation valve on the capillary tube 2 that penetrates the containment penetration 6. In order to ensure the response time of the remote transmitter, the diameter of the capillary tube 2 should be at least 1 / 4" OD.

[0024] The remote transmission diaphragm box includes a first remote transmission diaphragm box 4 and a second remote transmission diaphragm box 5. The first remote transmission diaphragm box 4 and the second remote transmission diaphragm box 5 are respectively fixed on the inner wall of the containment shell 3 through a mounting bracket. The second remote transmission diaphragm box 5 is located above the first remote transmission diaphragm box 4. The first remote transmission diaphragm box 4 and the second remote transmission diaphragm box 5 are both connected to the transmitter body 1 through a capillary 2. Under normal operating conditions, there is no liquid in the containment shell 3, and the first remote transmission diaphragm box 4 and the second remote transmission diaphragm box 5 sense the same pressure. Under accident conditions, after cooling water exists in the containment shell 3, the first remote transmission diaphragm box 4 and the second remote transmission diaphragm box 5 sense the liquid pressure at different heights respectively. The pressure is transmitted to the transmitter body 1 through the capillary 2. The pressure difference between the two is sensed in the transmitter body 1, and the containment shell liquid level is calculated.

[0025] In order to minimize the impact of high temperature environment, the capillary 2 connected to the first remote transmission membrane box 4 and the second remote transmission membrane box 5 horizontally passes through the containment shell 3 and extends horizontally to the normal temperature zone. After reaching the normal temperature zone, it extends vertically and is finally connected to the transmitter body 1.

[0026] The capillary 2 is filled with a filling liquid that can withstand long-term high temperatures, such as high-temperature silicone oil or liquid metal that can withstand temperatures above 200° C., to ensure the stability and transmission time of the pressure sensing system of the capillary 2 .

[0027] Because the inner part of the shell is made of high-temperature resistant metal materials or high-temperature resistant filling liquid, it can cope with the harsh environment of the compact small reactor containment with a long-term ambient temperature of more than 200°C and an accident peak temperature of more than 300°C, and realize accurate measurement of the liquid level in the small reactor containment; and through the reasonable selection of materials such as radiation-resistant filling liquid, it can cope with 10 5 Gy or above high radiation environment.

[0028] The containment shell 3 is provided with a containment shell penetration piece 6, which is arranged horizontally, and both ends of the containment shell penetration piece 6 penetrate the containment shell 3, and the capillary tubes 2 inside and outside the containment shell 3 are connected through the containment shell penetration piece 6 to ensure the sealing and integrity of the capillary tubes 2 and the containment shell 3. Specifically, as Figure 2 As shown, welding joints are provided on the capillary tube 2 on both sides inside and outside the containment shell 3, and welding interfaces are provided on the end faces of both ends of the containment shell penetration piece 6. The welding joints at the ends of the capillary tube 2 are welded and fixed to the welding interfaces on the end faces of the containment shell penetration piece 6, thereby realizing the connection between the capillary tube 2 and the containment shell penetration piece 6.

[0029] After completing the connection between the capillary tube 2 and the containment penetration piece 6, it is also necessary to verify the sealing and integrity of the capillary tube 2 and the containment shell 3, wherein the sealing and integrity of the capillary tube 2 are verified by a vacuum box detection method, and the sealing and integrity of the containment shell 3 as a whole are verified by a containment shell leakage test. The above-mentioned vacuum box detection method and containment shell leakage test are both existing technologies and will not be described in detail here.

[0030] In another embodiment, Figure 3 As shown, the capillary tube 2 may be cut off at the point where the containment shell is penetrated instead of providing a welding joint. A containment shell penetration piece 6 with a through hole in the middle is provided at the point where the containment shell 3 is penetrated. The capillary tube 2 inside the containment shell 3 and the capillary tube 2 outside the containment shell 3 are welded to both ends of the containment shell penetration piece 6 respectively, that is, the containment shell penetration piece 6 participates in pressure transmission as a part of the capillary system.

[0031] In order to facilitate the regular calibration of the containment liquid level measuring instrument and ensure the accuracy of the measurement, a calibration pipeline is also provided, such as Figure 4As shown, the verification pipeline includes a first pipeline 7 and a second pipeline 8. The first pipeline 7 is provided on the first remote transmission membrane box 4 and the second remote transmission membrane box 5. The first pipeline 7 is used for sensing the pressure of the liquid level in the containment shell 3. The first pipeline 7 is provided with a first valve 9. The first valve 9 is an electrically controlled valve, which is used to control the on and off of the first pipeline 7. It is electrically connected to a controller arranged outside the containment shell 3 for control. The first valve 9 is normally open under normal circumstances. The first pipeline 7 between the first valve 9 and the remote transmission membrane box is connected with a second pipeline 8. The second pipeline 8 passes through the containment shell 3 and extends to the outside of the containment shell 3. To ensure the sealing of the containment shell 3, the second pipeline 8 passes through the containment shell 3 through the containment shell penetration 6. The end of the second pipeline 8 away from the first pipeline 7 is connected with a pressure verification device 11. The pressure verification device is a common pressure verification device on the market. The pressure verification device 11 is detachably connected to the second pipeline 8, so that the pressure verification device 11 is put away when no verification is performed to avoid damage to the pressure verification device 11. The second pipeline 8 is also provided with a second valve 10 , which is located outside the containment shell 3 and is used to control the on-off of the second pipeline 8 .

[0032] When in use, first close the first valve 9, disconnect the connection between the first pipeline 7 and the inside of the containment shell 3 to avoid affecting the verification result, then connect the pressure verification device 11 to the second pipeline 8, open the second valve 10, and make the pressure verification device 11 communicate with the remote transmission diaphragm box located inside the containment shell 3 through the second pipeline 8. The pressure output by the pressure verification device 11 is transmitted to the remote transmission diaphragm box through the second pipeline 8, and is transmitted to the transmitter body 1 through the capillary 2. By reading the output of the remote transmission transmitter body 1, the accuracy of the transmitter body 1 is determined and calibrated as needed. By setting the verification pipeline, it is possible to implement regular verification of the remote transmission transmitter system outside the containment shell 3, thereby improving the convenience of regular maintenance.

[0033] Embodiment 2 This embodiment provides an integrated compact small reactor containment liquid level measurement method, using an integrated compact small reactor containment liquid level measurement system as described in the first embodiment, including the following steps: Under accident conditions, after cooling water exists in the containment, the first remote transmission diaphragm box and the second remote transmission diaphragm box respectively sense the liquid pressure at different heights, and transmit the liquid pressure to the transmitter body through the capillary tube. The transmitter body obtains the pressure difference measured by the first remote transmission diaphragm box and the second remote transmission diaphragm box in the containment according to the received liquid pressure, and calculates the liquid level of the containment according to the pressure difference. By arranging the first remote transmission diaphragm box and the second remote transmission diaphragm box in the containment and connecting them with the transmitter body arranged outside the containment through the capillary tube, the first remote transmission diaphragm box and the second remote transmission diaphragm box are used to sense the liquid pressure at different heights, so that the transmitter body calculates the liquid level in the containment through the pressure difference between the two. Compared with the traditional method of measuring the liquid level of the containment by using a nuclear-grade magnetic float level gauge, the internal space occupied by the containment is reduced, so that it can be used for an integrated compact small reactor to realize the liquid level measurement of the integrated compact small reactor.

[0034] The calculation formula of containment liquid is:

[0035] In the formula, ΔP is the pressure difference measured by the first remote pressure transmission diaphragm box and the second remote pressure transmission diaphragm box in the containment, ρ is the water density in the containment, and g is the gravitational acceleration. The water density ρ in the containment is obtained through the temperature and pressure in the containment, and the influence of the capillary height difference is compensated according to the density of the filling liquid in the capillary.

[0036] When the accuracy of the transmitter needs to be verified, such as Figure 5 As shown, the first valve is closed, the second valve is opened, and the pressure calibration device is connected to the second pipeline. The pressure output by the pressure calibration device is transmitted to the remote transmission diaphragm box through the second pipeline, and is transmitted to the transmitter body through the capillary. By reading the output of the remote transmission transmitter body, the accuracy of the transmitter body is determined and calibrated as needed. The present invention can implement regular calibration of the remote transmission transmitter system outside the containment, is suitable for integrated compact small reactors, and improves the convenience of regular maintenance.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An integrated compact small reactor containment liquid level measurement system, characterized in that: It includes a remote transmission membrane box, a capillary tube and a transmitter body, wherein the remote transmission membrane box is arranged inside the containment shell, the transmitter body is arranged outside the containment shell, and the transmitter body and the remote transmission membrane box are connected through the capillary tube; The remote transmission membrane box comprises a first remote transmission membrane box and a second remote transmission membrane box, and the first remote transmission membrane box and the second remote transmission membrane box are respectively fixed on the inner wall of the containment shell through mounting brackets.

2. The integrated compact small reactor containment liquid level measurement system according to claim 1, characterized in that: The capillary is filled with a filling liquid, and the filling liquid can withstand long-term high temperature.

3. The integrated compact small reactor containment liquid level measurement system according to claim 1, characterized in that: The containment shell is provided with a containment shell penetration piece, which is arranged horizontally, and both ends of the containment shell penetration piece penetrate the containment shell, and the capillaries inside and outside the containment shell are connected through the containment shell penetration piece.

4. The integrated compact small reactor containment liquid level measurement system according to claim 3, characterized in that: Welding joints are arranged on the capillaries on both sides of the containment, welding interfaces are arranged on the end faces of both ends of the containment penetration piece, and the welding joints at the ends of the capillaries are welded and fixed to the welding interfaces on the end faces of the containment penetration piece.

5. The integrated compact small reactor containment liquid level measurement system according to claim 1, characterized in that: A calibration pipeline is also provided, which includes a first pipeline and a second pipeline. The first pipeline is provided with two, and the two first pipelines are respectively connected to the first remote transmission membrane box and the second remote transmission membrane box, and the second pipeline is connected to the first pipeline.

6. The integrated compact small reactor containment liquid level measurement system according to claim 5, characterized in that: The first pipeline is provided with a first valve, which is an electrically controlled valve connected to a controller arranged outside the containment vessel.

7. The integrated compact small reactor containment liquid level measurement system according to claim 6, characterized in that: One end of the second pipeline is connected to the first pipeline between the first valve and the remote transmission membrane box, and the other end passes through the containment shell and extends to the outside of the containment shell. A second valve is arranged on the second pipeline outside the containment shell.

8. The integrated compact small reactor containment liquid level measurement system according to claim 7, characterized in that: One end of the second pipeline away from the first pipeline is connected with a pressure checking device, and the pressure checking device is detachably connected to the second pipeline.

9. An integrated compact small reactor containment liquid level measurement method, using an integrated compact small reactor containment liquid level measurement device as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: Under accident conditions, when cooling water exists in the containment, the first remote transmission diaphragm box and the second remote transmission diaphragm box respectively sense the liquid pressure at different heights, and transmit the liquid pressure to the transmitter body through the capillary. The transmitter body obtains the pressure difference measured by the first remote transmission diaphragm box and the second remote transmission diaphragm box in the containment according to the received liquid pressure, and calculates the liquid level of the containment according to the pressure difference.

10. The integrated compact small reactor containment liquid level measurement method according to claim 9, characterized in that: The following steps are also included: When it is necessary to calibrate the accuracy of the transmitter body, close the first valve, open the second valve, connect the pressure calibration device to the second pipeline, and the pressure output by the pressure calibration device is transmitted to the remote transmission diaphragm box through the second pipeline, and is transmitted to the transmitter body through the capillary. By reading the output of the remote transmission transmitter body, the accuracy of the transmitter body is determined and calibrated as needed.

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