Radioactive waste liquid surface contamination multi-point array detection system

Abstract

A multi-point array detection system for radioactive waste liquid surface contamination is used to monitor radioactive contamination on the surface of radioactive waste liquid storage tanks. It includes a main frame, a movement control device, detectors, and a host computer. The main frame has multiple mounting holes arranged in a planar array. The movement control device controls the main frame to move closer to or further away from the surface of the radioactive waste liquid storage tank, and to move into or out of the area above the surface. Multiple detectors are installed in the mounting holes of the main frame, with all detectors facing the surface of the radioactive waste liquid storage tank. The host computer is used to adjust the parameters of the CMOS sensors, and to store, display, analyze, and process frame images. This invention, through a detachable array of detectors arranged in a planar array, can cover the entire surface area of ​​the radioactive waste liquid storage tank in one measurement, obtaining a panoramic view of the contamination distribution in a single measurement, reducing the time required for point-by-point detection from several hours to just minutes.

Description

Technical Field

[0001] This utility model relates to the field of nuclear radiation detection technology, and in particular to a multi-point array detection system for surface contamination of radioactive waste liquid. Background Technology

[0002] Monitoring surface contamination in radioactive waste storage tanks is a critical aspect of radiation protection for nuclear facilities, directly impacting the operational safety and decommissioning efficiency of nuclear power plants and reprocessing plants. Traditional monitoring methods primarily rely on single-point surface contamination detectors (such as plastic scintillator detectors) for point-by-point scanning or suspended fixed monitoring, but these methods have the following drawbacks in practical applications.

[0003] 1. Difficulty in covering large areas: The surface area of ​​radioactive waste storage tanks can reach tens to hundreds of square meters. Traditional single-point detectors rely on robotic arm trajectory scanning, and a single measurement can take several hours. Although the CoMo series of portable radioactive contamination monitors launched by NUVIA in the United States can support mobile measurement, it is limited by the effective area of ​​the probe and cannot achieve synchronous panoramic monitoring of contamination distribution.

[0004] 2. Poor environmental adaptability: The surface of radioactive waste liquid often contains vapor volatilization or foam layers, causing the measurement fluctuation value of traditional plastic scintillator detectors to exceed ±30%. The aluminum film used for light shielding on the surface of the plastic scintillator is prone to oxidation and peeling in high temperature and high humidity environments (lifespan <6 months), thus causing false alarms of radioactive contamination.

[0005] In summary, existing monitoring methods are insufficient for simultaneous monitoring of large liquid surfaces and for adapting well to complex liquid surface environments. There is an urgent need for a modular, freely deployable multi-point array system of detectors to achieve efficient and accurate monitoring of radioactive waste liquid surface contamination. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a multi-point array detection system for surface contamination of radioactive waste liquid. It solves the problems that current methods for monitoring surface contamination of radioactive waste liquid are difficult to achieve simultaneous monitoring of large-area liquid surfaces and have poor adaptability to complex liquid surface environments.

[0007] The technical solution of this utility model is: a multi-point array detection system for surface contamination of radioactive waste liquid, used to monitor radioactive contamination on the surface of a radioactive waste liquid storage tank; the radioactive waste liquid storage tank is a trough-shaped container with an open top; the multi-point array detection system for surface contamination of radioactive waste liquid includes a main frame, a movement control device, a detector, and a host computer;

[0008] The main frame has multiple mounting holes arranged in a planar array;

[0009] The mobile control device is fixedly installed on the ground outside the radioactive waste liquid storage tank and is movably connected to the main fixed frame. It controls the main fixed frame to move closer to or away from the liquid surface of the radioactive waste liquid storage tank through vertical lifting operation, and controls the main fixed frame to move into or out of the area above the liquid surface of the radioactive waste liquid storage tank through horizontal rotation operation.

[0010] Multiple detectors are detachably installed in various mounting holes of the main frame, with only one detector installed in each hole. All detectors face directly towards the surface of the radioactive waste storage tank. The detector includes a housing, a detection module, a battery module, communication components, and a circuit integrated converter. The housing is made of a radiation-permeable material and has an internal cavity. The detection module includes a CMOS sensor, a circuit board, a chip board, and a housing. The photosensitive surface of the CMOS sensor is not encapsulated in glass and is coated with a light-shielding aluminum film. The CMOS sensor is fixedly mounted on a circuit board with a power supply interface, and the circuit board communicates with the chip board. A SOC chip for outputting frame images is mounted on the chip board. The housing is made of radiation-shielding material and has an internal cavity. One side of the housing has an entrance hole connecting to the internal cavity, the shape and size of which are the same as those of the photosensitive surface. The circuit board and chip board are both fixedly installed inside the housing cavity, with the photosensitive surface of the CMOS sensor facing the entrance aperture of the housing. The detection module is fixedly installed inside the housing cavity, and external α and β rays pass through the housing wall and the entrance aperture in sequence, incident on the photosensitive surface of the CMOS sensor. The battery module and the integrated circuit converter are both fixedly installed inside the housing cavity. The communication components include a wireless communication antenna and an auxiliary communication antenna. The integrated circuit converter includes a multi-channel voltage conversion module and a communication protocol conversion module. The input of the multi-channel voltage conversion module is connected to the battery module, and the output of the multi-channel voltage conversion module is divided into multiple power supplies connected to each power-requiring component. The input of the communication protocol conversion module is connected to the chip board, and the output of the communication protocol conversion module is connected to the wireless communication antenna and the auxiliary communication antenna, respectively. The orientation of the photosensitive surface of the CMOS sensor is the detection direction of the detector.

[0011] The host computer is connected to both the wireless communication antenna and the auxiliary communication antenna. The host computer is used to adjust the parameters of the CMOS sensor, as well as to store, display, analyze and process frame images containing radiation response signals.

[0012] A further technical solution of this utility model is as follows: the main body fixing frame is movably connected to the motion control device through a connecting component; the connecting component includes a threading ring, a connecting rope, and a lifting ring; multiple threading rings are evenly distributed in a ring around the center of gravity of the main body fixing frame at the upper end of the main body fixing frame, the number of connecting ropes is the same as the number of threading rings and corresponds one-to-one, the connecting ropes are connected to the threading rings at the lower end and to the lifting rings at the upper end; when the entire main body fixing frame is lifted by the lifting rings, all connecting ropes bear equal tension, the main body fixing frame is in a horizontal state, and in the horizontal state, all mounting holes on the main body fixing frame are arranged at the same height.

[0013] A further technical solution of this utility model is: the mobile control device is a cantilever crane; the cantilever crane includes a column, a cantilever, a slewing device, and a lifting device; the cantilever is rotatably connected to the upper end of the column and rotates horizontally under the drive of the slewing device; the slewing device is installed between the column and the cantilever; the lifting device is installed at the lower end of the cantilever; the lifting device includes a motor, a reducer, a drum, and a wire rope, the power of the motor is transmitted to the drum through the reducer, driving the drum to rotate, thereby driving the wire rope wound on the drum to be wound up and down, and a hook is provided at the lower end of the wire rope; the cantilever crane is movably connected to the lifting ring through the hook, thereby realizing the movable connection with the main fixed frame.

[0014] A further technical solution of this utility model is as follows: it also includes a lifting guide frame; multiple lifting guide frames are fixedly installed on the ground outside the radioactive waste liquid storage tank; the lifting guide frame is provided with vertically arranged guide protrusions; the upper end of the lifting guide frame is provided with a chamfer for guiding the main body fixing frame to be lowered; correspondingly, the edge of the main body fixing frame is provided with a guide notch that matches the guide protrusions; the main body fixing frame is slidably installed horizontally between all the lifting guide frames through the cooperation relationship between the guide notch and the guide protrusions.

[0015] A further technical solution of this utility model is: the detector also includes a cooling fan; the cooling fan is fixedly installed in the inner cavity of the outer shell, and the two ends of the cooling fan are the air inlet and the air outlet, respectively, with the air outlet of the cooling fan facing the detection module; the outer shell is provided with an air inlet hole facing the air inlet of the cooling fan.

[0016] A further technical solution of this utility model is as follows: the outer shell of the detector is rectangular, and two symmetrically arranged hanging ears are provided on the outer wall of the outer shell; correspondingly, each mounting hole of the main body fixing frame has a positioning recess on both sides for the hanging ears of the detector to be inserted; when the detector is inserted into the mounting hole of the main body fixing frame from top to bottom, the lower end of the detector extends out of the lower end of the main body fixing frame, and the two hanging ears of the detector are respectively inserted into the positioning recesses on both sides of the mounting hole, and the photosensitive surface of the CMOS sensor is parallel to the axis of the mounting hole.

[0017] A further technical solution of this utility model is: the wireless communication antenna is an external 5.8GHz WiFi antenna, which is used for real-time uploading of detection data; the auxiliary communication antenna is a dual-mode Bluetooth antenna that supports both classic Bluetooth and low-power Bluetooth, which is used to maintain the standby of the detection module, set CMOS sensor parameters, control the start and stop of the detection task, and transmit basic alarm signals when the wireless communication antenna is shielded.

[0018] A further technical solution of this utility model is: the thickness of the light-shielding aluminum film is uniform throughout, and the thickness of the light-shielding aluminum film is 200±50nm.

[0019] A further technical solution of this utility model is: the wireless communication antenna is connected to the communication protocol conversion module through the SDIO interface, and the auxiliary communication antenna is connected to the communication protocol conversion module through the UART interface.

[0020] This utility model has the following advantages compared with the prior art:

[0021] 1. Achieve large-area synchronous panoramic monitoring, significantly improving detection efficiency: Through a detachable array of detectors arranged in a planar array, the entire surface area of ​​the radioactive waste storage tank can be covered in one go, overcoming the limitations of traditional single-point detectors that can only scan point by point or monitor fixed points. A panoramic view of the contamination distribution can be obtained in a single measurement, reducing the time required for point-by-point detection from several hours to several minutes, significantly improving the operation and maintenance efficiency of nuclear facilities.

[0022] 2. Overcoming bottlenecks in monitoring complex liquid environments and ensuring data reliability: The detection module is installed in a sealed inner cavity, effectively isolating vapor and preventing contamination of the CMOS sensor. The outer shell is made of a radiation-permeable material, while the inner shell is made of a radiation-shielding material with an entrance hole, ensuring that the CMOS sensor can receive external α and β radiation (α and β rays pass through the outer shell and the entrance hole in sequence, thus incident on the photosensitive surface of the CMOS sensor). If the detector outer shell becomes contaminated, the main frame and all detectors mounted on it are lifted together using a movement control device, causing the main frame to move out of the guide range of the lifting guide frame. Then, the movement control device drives the main frame and all detectors mounted on it to rotate to the upper outer area of ​​the radioactive waste storage tank. Finally, all detector outer shells are rinsed to remove the radioactive nuclides adhering to them, allowing the detectors to be put back into use.

[0023] 3. Modular design ensures flexibility and maintainability: The detectors can be quickly plugged in and out via the cooperation of the mounting ears and positioning recesses, and the array density and arrangement can be dynamically adjusted according to actual monitoring needs. Individual detectors can be replaced if one fails, avoiding system downtime and reducing maintenance costs.

[0024] 4. The detector balances low cost and high precision: The core detection component, the CMOS sensor, requires only minor modifications (removing the glass encapsulation on the photosensitive surface and depositing an aluminum film on it), resulting in relatively lower manufacturing costs compared to traditional radioactive contamination detectors. CMOS sensors do not exhibit the boundary effects of plastic scintillators, enabling high-precision radiation detection across their entire photosensitive surface.

[0025] 5. The detector combines high sensitivity with good environmental adaptability: The core component of the detector, the CMOS sensor, is inherently sensitive to both incident alpha and beta particles, generating response signals of different shapes, thus providing the hardware foundation for accurate discrimination of alpha and beta rays. Furthermore, the industrial-grade CMOS sensor operates within a temperature range of -40℃ to 60℃, a wider range compared to traditional plastic scintillators. Combined with a cooling fan, this further ensures the detector's stability during prolonged high-temperature operation.

[0026] 6. Dual-mode communication architecture: The detector's communication components innovatively integrate a 5.8GHz WiFi antenna and a dual-mode Bluetooth antenna, which work together through a communication protocol conversion module. The 5.8GHz WiFi antenna is used to upload detection data (continuous frame images) to the host computer in real time, meeting the IAEA core emergency real-time response standard. The Bluetooth BLE mode can maintain standby power consumption of less than 0.1mA, significantly improving the device's battery life. When WiFi is blocked (5.8GHz signal strength < -90dBm), it automatically switches to Bluetooth (auxiliary communication antenna) to transmit basic alarm signals, ensuring reliability under extreme operating conditions.

[0027] The present invention will be further described below with reference to the figures and embodiments. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of this utility model;

[0029] Figure 2 This is a schematic diagram of the main fixing frame in this utility model;

[0030] Figure 3 This is an external view of the detector;

[0031] Figure 4 This is a schematic diagram showing the power supply and communication connections of the various components in this utility model;

[0032] Figure 5 This is a simplified structural diagram of the detection module.

[0033] Legend: Radioactive waste liquid storage tank 100; Cooling fan 200; Main body fixing frame 1; Mounting hole 11; Threading ring 12; Connecting rope 13; Lifting ring 14; Positioning recess 15; Guide notch 16; Movement control device 2; Column 21; Cantilever 22; Steel wire rope 231; Hook 232; Housing 3; Hanging lug 31; Detection module 4; CMOS sensor 41; Circuit board 42; Chip board 43; SOC chip 431; Housing 44; Entrance hole 441; Battery module 5; Communication component 6; Wireless communication antenna 61; Auxiliary communication antenna 62; Line integrated converter 7; Multi-channel voltage conversion module 71; Communication protocol conversion module 72; Lifting guide frame 8; Guide protrusion 81; Avoidance chamfer 82; Host computer 9. Detailed Implementation

[0034] Example 1:

[0035] like Figure 1-5 As shown, a multi-point array detection system for surface contamination of radioactive waste liquid is used to monitor radioactive contamination on the surface of a radioactive waste liquid storage tank 100. The radioactive waste liquid storage tank 100 is a trough-shaped container with an open top. The multi-point array detection system for surface contamination of radioactive waste liquid includes a main frame 1, a movement control device 2, detectors, and a host computer.

[0036] The main frame 1 has multiple mounting holes 11 arranged in a planar array. The main frame 1 is movably connected to the movement control device 2 via a connecting assembly. The connecting assembly includes threaded loops 12, connecting ropes 13, and lifting rings 14. Multiple threaded loops 12 are evenly distributed in a ring around the center of gravity of the main frame 1 at the upper end (the upper end is the upper surface, and the connection method is welding). The number of connecting ropes 13 is the same as the number of threaded loops 12 and corresponds one-to-one. The lower end of the connecting rope 13 is connected to the threaded loop 12, and the upper end of the connecting rope 13 is connected to the lifting ring 14. When the entire main frame 1 is lifted only by the lifting ring 14, all connecting ropes 13 bear equal tension, the main frame 1 is in a horizontal state, and in the horizontal state, all mounting holes 11 on the main frame 1 are arranged at the same height.

[0037] The mobile control device 2 is fixedly installed on the ground outside the radioactive waste storage tank 100 and is movably connected to the main frame 1. It controls the main frame 1 to move closer to or further away from the liquid surface of the radioactive waste storage tank 100 via vertical lifting operations, and controls the main frame 1 to move out of the area above the liquid surface of the radioactive waste storage tank 100 via horizontal rotation operations. The mobile control device 2 is a cantilever crane. The cantilever crane includes a column 21, a cantilever 22, a slewing device (not shown in the figure), and a lifting device. The cantilever 22 is rotatably connected to the upper end of the column 21 and rotates horizontally under the drive of the slewing device. The slewing device is installed between the column 21 and the cantilever 22. The lifting device is installed at the lower end of the cantilever 22. The lifting device includes a motor, a reducer, a drum, and a wire rope 231. The motor, reducer, and drum are all installed at the lower end of the cantilever 22. The power of the motor is transmitted to the drum through the reducer, driving the drum to rotate, which in turn drives the wire rope 231 wound on the drum to be unwound and retracted. A hook 232 is provided at the lower end of the wire rope 231. The cantilever crane is movably connected to the lifting ring 14 through the hook 232, thereby achieving a movable connection with the main fixed frame 1.

[0038] Multiple detectors are detachably installed in each mounting hole 11 of the main body fixing frame 1. Only one detector is installed in each mounting hole 11, and the detection direction of all detectors is facing the liquid surface of the radioactive waste liquid storage tank 100.

[0039] The detector includes a housing 3, a detection module 4, a battery module 5, a communication component 6, and a line integrated converter 7.

[0040] The outer shell 3 is made of a radiation-permeable material, and the inner cavity is provided inside the outer shell 3.

[0041] The detection module 4 includes a CMOS sensor 41, a circuit board 42, a chip board 43, and a housing 44. The photosensitive surface of the CMOS sensor 41 is not encapsulated with glass and is coated with a light-shielding aluminum film. The CMOS sensor 41 is fixedly mounted on the circuit board 42, which has a power supply interface. The circuit board 42 is communicatively connected to the chip board 43. A SOC chip 431 for outputting frame images is mounted on the chip board 43. The housing 44 is made of radiation-shielding material and has an internal cavity. One side of the housing 44 has an entrance hole 441 that connects to the internal cavity. The shape and size of the entrance hole 441 are consistent with the shape and size of the photosensitive surface. The circuit board 42 and the chip board 43 are both fixedly mounted in the internal cavity of the housing 44, with the photosensitive surface of the CMOS sensor 41 facing the entrance hole 441 of the housing 44. The detection module 4 is fixedly mounted inside the cavity of the outer shell 1. External α and β rays pass sequentially through the wall of the outer shell 3 and the entrance hole 441 of the housing 44, and then incident on the photosensitive surface of the CMOS sensor 41.

[0042] The battery module 5 is fixedly installed inside the housing 1. The battery module 5 is specifically a 5V 3A rechargeable lithium battery.

[0043] Communication component 6 includes a wireless communication antenna 61 and an auxiliary communication antenna 62. The wireless communication antenna 61 is mounted externally to the housing 1 and is an external 5.8GHz WiFi antenna used for real-time uploading of detection data (continuous frame images). The auxiliary communication antenna 62 is mounted internally to the housing 1 and is a dual-mode Bluetooth antenna supporting both classic Bluetooth and Bluetooth Low Energy. It is used to maintain the detection module 4 in standby mode, set parameters for the CMOS sensor 41, control the start and stop of detection tasks, and transmit basic alarm signals when the wireless communication antenna 61 is shielded.

[0044] The line integrated converter 7 is fixedly installed inside the housing 3. The line integrated converter 7 includes a multi-channel voltage conversion module 71 (for power management of various powered components) and a communication protocol conversion module 72 (for signal relay and protocol adaptation). The input of the multi-channel voltage conversion module 71 is connected to the battery module 5 to control the overall power supply. The output of the multi-channel voltage conversion module 71 is divided into multiple power supplies connected to each powered component, providing power support to each component. The input of the communication protocol conversion module 72 is connected to the chip board 43, and the output of the communication protocol conversion module 72 is connected to the wireless communication antenna 61 and the auxiliary communication antenna 62, respectively. The orientation of the photosensitive surface of the CMOS sensor 41 is the detection direction of the detector.

[0045] The host computer 9 is communicatively connected to both the wireless communication antenna 61 and the auxiliary communication antenna 62. The host computer 9 is used to control the parameters of the CMOS sensor 41, as well as to store, display, analyze, and process frame images containing radiation response signals. The host computer 9 receives basic alarm signals transmitted by the auxiliary communication antenna 42 via Bluetooth and displays them to alert personnel to handle the situation.

[0046] Preferably, the wall surface of the housing 3 facing the CMOS sensor is the bottom wall, the outer surface of the bottom wall of the housing 3 is a plane, the photosensitive surface of the CMOS sensor is parallel to the outer surface of the bottom wall of the housing 3, and the distance between the photosensitive surface of the CMOS sensor and the outer surface of the bottom wall of the housing 3 is less than 5mm.

[0047] Preferably, it also includes lifting guide frames 8. Multiple lifting guide frames 8 are fixedly installed on the ground outside the radioactive waste storage tank 100. Each lifting guide frame 8 has vertically arranged guide protrusions 81. The upper end of each lifting guide frame 8 has a chamfer 82 for guiding the lowering of the main body fixing frame. Correspondingly, the edge of the main body fixing frame 1 has a guide notch 16 that matches the guide protrusions. The main body fixing frame 1 is horizontally slidably installed between all the lifting guide frames 8 through the cooperation between the guide notch 16 and the guide protrusions 81.

[0048] Preferably, the detector also includes a cooling fan 200. The cooling fan 200 is fixedly installed in the inner cavity of the housing 3, with an air inlet and an air outlet at its two ends, respectively. The air outlet of the cooling fan 200 is positioned directly opposite the detection module 4. The housing 3 is provided with an air inlet (not shown in the figure) positioned directly opposite the air inlet of the cooling fan 200.

[0049] Preferably, the detector housing 3 is rectangular, and two symmetrically arranged lugs 31 are provided on the outer wall of the housing 3. Correspondingly, each mounting hole of the main body bracket 1 has a positioning recess 15 on both sides for the lugs 31 of the detector to be inserted. When the detector is inserted into the mounting hole 11 of the main body bracket 1 from top to bottom, the lower end of the detector extends out of the lower end of the main body bracket 1, and the two lugs 31 of the detector are respectively inserted into the positioning recesses 15 on both sides of the mounting hole 11. The photosensitive surface of the CMOS sensor 41 is parallel to the axis of the mounting hole 11.

[0050] Preferably, the light-shielding aluminum film deposited on the surface of the CMOS sensor 41 has a uniform thickness, and the thickness of the light-shielding aluminum film is 200±50nm.

[0051] Preferably, the wireless communication antenna 61 is connected to the communication protocol conversion module via the SDIO interface, and the auxiliary communication antenna 62 is connected to the communication protocol conversion module via the UART interface.

[0052] Briefly describe the working principle of this utility model:

[0053] Each detector is used to acquire radioactive contamination data (frame images containing radiation response signals) at different locations on the surface of the radioactive waste liquid storage tank. The data is then analyzed and processed by the host computer (corresponding to subsequent steps S02-S03) to achieve monitoring of the α and β contamination areas on the surface of the radioactive waste liquid storage tank.

[0054] The method is as follows:

[0055] S01, Pre-operation:

[0056] A. Sensor Calibration: The CMOS sensors 41 in all detectors are calibrated individually to eliminate interference from environmental noise and non-polluting factors on subsequent measurements. The calibration process includes measuring and storing the CMOS sensor 41 base data and setting the gain of the CMOS sensor 41; then each detector is numbered.

[0057] B. Constructing a detector group: The numbered detectors are inserted into the corresponding mounting holes 11 on the main body fixing frame 1 according to a specific array density and arrangement, thereby forming a detector group arranged in a planar array.

[0058] C. Position Adjustment: Connect the main body mounting frame 1 with the detector to the motion control device 2 via the connecting assembly. Activate the motion control device 2 to hoist the main body mounting frame 1 with the detector directly above the radioactive waste storage tank 100, ensuring that the guide notch 16 of the main body mounting frame 1 is approximately vertically aligned with the guide protrusion 81 of the lifting guide frame 8 ("approximately" means that the alignment error between the main body mounting frame 1 and the lifting guide frame 8 is within the range guided and corrected by the chamfer 82 of the lifting guide frame 8). Operate the motion control device 2 to move the main body mounting frame 1 with the detector... The main body fixing frame 1 is slowly lowered (the term "slowly" means that the main body fixing frame 1 is stable and does not shake). Guided and corrected by the chamfer 82 of the lifting guide frame 8, the guide notch 16 of the main body fixing frame 1 is engaged in the guide protrusion 81 of the lifting guide frame 8. At this time, a sliding contact is formed between the main body fixing frame 1 and the lifting guide frame 8. The main body fixing frame 1 is lowered smoothly and does not shake through the guiding action of the lifting guide frame 8. The descent stops when the distance between the photosensitive surface of the CMOS sensor 41 and the liquid surface of the radioactive waste liquid storage tank 100 is less than 1 cm.

[0059] D. Data Acquisition: All detectors are activated simultaneously, with each detector scanning a specific area on the surface of the radioactive waste storage tank. The sampling interval (e.g., all detectors use a sampling interval of 1 minute / sample) and the start sampling time (e.g., all detectors start sampling at 13:00, 13:01, 13:02, etc.) of all detectors are the same, thus acquiring multiple sets of radiation data. Each set of radiation data contains multiple frame images at the same timestamp, with each frame image coming from a corresponding detector. Each set of data contains multiple consecutive frame images. Each detector uploads the acquired frame images to the host computer 9 in real time via wireless communication antenna 61.

[0060] S02, Feature Extraction:

[0061] The host computer performs the following operations on each group of radiation data:

[0062] A. Response signal extraction: A set of radiation data is converted into a set of grayscale images, and then noise removal and background correction are performed to extract the effective radiation response signal from each grayscale image contained in the set of grayscale images.

[0063] B. Feature parameter calculation: Calculate the feature parameters of the extracted radiation response signal. The feature parameters include one or more of the following: average pixel value, distribution pattern, and number of pixels.

[0064] C. Response signal differentiation: Given that the radiation response signal only contains α and β response signals, based on the inherent characteristic parameters of α and β response signals (obtained and recorded through prior experiments), α and β response signals are differentiated from each grayscale image contained in a set of grayscale images.

[0065] In this step, the average pixel value is used to characterize the overall brightness level of the radiative response signal, and the calculation formula is shown in Formula 1.

[0066] Formula 1:

[0067] In the formula, M is the average pixel value of the connected region, P is the number of pixels in the connected region, δ is the filtering function used to determine whether the target pixel belongs to the connected region, the connected region is the area occupied by a radiation response signal in the frame image; (i,j) represents the pixel in the i-th row and j-th column, n and m represent the number of rows and columns of pixels, respectively, I(i,j) represents the pixel value of the pixel in the i-th row and j-th column, and T is the pixel value threshold of the connected region.

[0068] In this step, the number of pixels refers to the number of pixels in the connected region, which is used to reflect the area size of the radiation response signal. The calculation formula is shown in Formula 2.

[0069] Formula 2:

[0070] In the formula, P is the number of pixels in the connected region.

[0071] In this step, the α response signal exhibits a target-shaped distribution characteristic in the distribution pattern. The target-shaped distribution characteristic is manifested as follows: the α response signal includes a central region and a ring zone from the inside out. The gray value of the pixels in the central region is above 230, and the gray value of the pixels in the ring zone is between 30 and 150. Multiple sub-rings with a decreasing gradient distribution of gray values ​​are formed from the inside to the outside of the ring zone. The β response signal does not have the target-shaped distribution characteristic.

[0072] In this step, at the 9dB, 32dB, or 63dB level, the average pixel value, distribution pattern, and number of pixels of the α response signal are significantly different from those of the β response signal. The α response signal and the β response signal can be distinguished by one or more of these features.

[0073] S03, data shows:

[0074] A. Group Display: The host computer 9 displays the radiation data of each group after feature extraction through the screen; the radiation data of each group is displayed in sequence according to the timestamp, and the display duration of a group of radiation data is the sampling interval of the detector; the display content of a group of radiation data includes the α response signal count and β response signal count obtained by processing multiple grayscale images under that group of data, that is, displaying multiple group counts with the same number of grayscale images, and marking the corresponding detector number on the screen (for example, Group 1 (detector number 001): 50,000 α response signals, 100,000 β response signals; Group 2 (detector number 002): 40,000 α response signals, 90,000 β response signals).

[0075] B. Alarm Mechanism: For detector groups whose α response signal count or β response signal count exceeds the preset threshold, the host computer 9 executes a graded alarm.

[0076] Level 1 Alarm (Local Warning) (Applicable Scenario: Short-term minor pollution, requiring manual verification):

[0077] When the count of α or β response signals of a detector group exceeds the operating threshold (pre-set according to GB18871 standard) in a single sampling, the host computer 9 marks the detector number in real time and displays an orange box in the corresponding area of ​​the screen;

[0078] Level 2 Alarm (Emergency Response) (Applicable Scenarios: Persistent severe pollution requiring emergency intervention):

[0079] When the α or β response signal count of the same detector group exceeds the intervention threshold (3 times the operation threshold) in 3 consecutive samplings, or the single sampling count exceeds the tolerance threshold (10 times the operation threshold), the host computer 9 marks the detector number in real time and displays a red box in the corresponding area of ​​the screen. It also automatically generates a pollution diffusion trend chart, which is superimposed on the center area of ​​the display interface with 50% transparency and 50% screen ratio. The sampling task of the detector group is paused (to avoid data overload), and an alarm prompt is triggered at the same time (provided that the host computer 9 is connected to an alarm).

[0080] C. Self-testing mechanism: When the α or β response signal count of a detector group is 0 for 5 consecutive samples, the host computer 9 determines that "the detector has failed" and wakes up the cooling fan 200 of the detector via Bluetooth command and checks the voltage fluctuation; if there is no device status feedback within 10 seconds, the point is automatically marked as "faulty" and a yellow alarm is triggered to remind the staff to replace the detector.

Claims

1. A multi-point array detection system for surface contamination of radioactive waste liquid, used to monitor radioactive contamination on the surface of a radioactive waste liquid storage tank; wherein the radioactive waste liquid storage tank is a trough-shaped container with an open top. Its characteristics are: A multi-point array detection system for surface contamination of radioactive waste liquid includes a main frame, a motion control device, a detector, and a host computer. The main frame has multiple mounting holes arranged in a planar array; The mobile control device is fixedly installed on the ground outside the radioactive waste liquid storage tank and is movably connected to the main fixed frame. It controls the main fixed frame to move closer to or away from the liquid surface of the radioactive waste liquid storage tank through vertical lifting operation, and controls the main fixed frame to move into or out of the area above the liquid surface of the radioactive waste liquid storage tank through horizontal rotation operation. Multiple detectors are detachably installed in various mounting holes of the main frame, with only one detector installed in each hole. All detectors face directly towards the surface of the radioactive waste storage tank. The detector includes a housing, a detection module, a battery module, communication components, and a circuit integrated converter. The housing is made of a radiation-permeable material and has an internal cavity. The detection module includes a CMOS sensor, a circuit board, a chip board, and a housing. The photosensitive surface of the CMOS sensor is not encapsulated in glass and is coated with a light-shielding aluminum film. The CMOS sensor is fixedly mounted on a circuit board with a power supply interface, and the circuit board communicates with the chip board. A SOC chip for outputting frame images is mounted on the chip board. The housing is made of radiation-shielding material and has an internal cavity. One side of the housing has an entrance hole connecting to the internal cavity, the shape and size of which are the same as those of the photosensitive surface. The circuit board and chip board are both fixedly installed inside the housing cavity, with the photosensitive surface of the CMOS sensor facing the entrance aperture of the housing. The detection module is fixedly installed inside the housing cavity, and external α and β rays pass through the housing wall and the entrance aperture in sequence, incident on the photosensitive surface of the CMOS sensor. The battery module and the integrated circuit converter are both fixedly installed inside the housing cavity. The communication components include a wireless communication antenna and an auxiliary communication antenna. The integrated circuit converter includes a multi-channel voltage conversion module and a communication protocol conversion module. The input of the multi-channel voltage conversion module is connected to the battery module, and the output of the multi-channel voltage conversion module is divided into multiple power supplies connected to each power-requiring component. The input of the communication protocol conversion module is connected to the chip board, and the output of the communication protocol conversion module is connected to the wireless communication antenna and the auxiliary communication antenna, respectively. The orientation of the photosensitive surface of the CMOS sensor is the detection direction of the detector. The host computer is connected to both the wireless communication antenna and the auxiliary communication antenna. The host computer is used to adjust the parameters of the CMOS sensor, as well as to store, display, analyze and process frame images containing radiation response signals.

2. The multi-point array detection system for surface contamination of radioactive waste liquid as described in claim 1, characterized in that: The main frame is movably connected to the motion control device via a connecting assembly. The connecting assembly includes threaded rings, connecting ropes, and lifting rings. Multiple threaded rings are evenly distributed in a ring around the center of gravity of the main frame at its upper end. The number of connecting ropes is the same as the number of threaded rings and corresponds one-to-one. The connecting ropes are connected to the threaded rings at their lower ends and to the lifting rings at their upper ends. When the entire main frame is lifted by the lifting rings, all connecting ropes bear equal tension, and the main frame is in a horizontal state. In the horizontal state, all mounting holes on the main frame are arranged at the same height.

3. The multi-point array detection system for surface contamination of radioactive waste liquid as described in claim 2, characterized in that: The mobile control device is a cantilever crane; the cantilever crane includes a column, a cantilever, a slewing device, and a hoisting device; the cantilever is rotatably connected to the upper end of the column and rotates horizontally under the drive of the slewing device; the slewing device is installed between the column and the cantilever; the hoisting device is installed at the lower end of the cantilever; the hoisting device includes a motor, a reducer, a drum, and a wire rope, the power of the motor is transmitted to the drum through the reducer, driving the drum to rotate, which in turn drives the wire rope wound on the drum to be wound up and down, and a hook is provided at the lower end of the wire rope; the cantilever crane is movably connected to the lifting ring through the hook, thereby realizing the movable connection with the main fixed frame.

4. The multi-point array detection system for surface contamination of radioactive waste liquid as described in claim 3, characterized in that: It also includes lifting guide frames; multiple lifting guide frames are fixedly installed on the ground outside the radioactive waste liquid storage tank; the lifting guide frames are provided with vertically arranged guide protrusions; the upper end of the lifting guide frames is provided with a chamfer for guiding the main body fixing frame to be lowered; correspondingly, the edge of the main body fixing frame is provided with a guide notch that matches the guide protrusions; the main body fixing frame is slidably installed horizontally between all the lifting guide frames through the cooperation between the guide notch and the guide protrusions.

5. The multi-point array detection system for surface contamination of radioactive waste liquid as described in claim 4, characterized in that: The detector also includes a cooling fan; the cooling fan is fixedly installed in the inner cavity of the housing, with the two ends of the cooling fan being the air inlet and the air outlet, respectively, and the air outlet of the cooling fan is arranged facing the detection module; the housing is provided with an air inlet hole arranged facing the air inlet of the cooling fan.

6. The multi-point array detection system for surface contamination of radioactive waste liquid as described in claim 5, characterized in that: The detector's housing is rectangular, with two symmetrically arranged lugs on its outer wall. Correspondingly, each mounting hole of the main body bracket has a positioning recess on both sides for the lugs of the detector to be inserted. When the detector is inserted into the mounting hole of the main body bracket from top to bottom, the lower end of the detector extends out of the lower end of the main body bracket, and the two lugs of the detector are respectively inserted into the positioning recesses on both sides of the mounting hole. The photosensitive surface of the CMOS sensor is parallel to the axis of the mounting hole.

7. The multi-point array detection system for surface contamination of radioactive waste liquid as described in claim 6, characterized in that: The wireless communication antenna is an external 5.8GHz WiFi antenna, which is used for real-time uploading of detection data; the auxiliary communication antenna is a dual-mode Bluetooth antenna that supports both classic Bluetooth and Bluetooth Low Energy, which is used to maintain the detection module in standby mode, set CMOS sensor parameters, control the start and stop of detection tasks, and transmit basic alarm signals when the wireless communication antenna is shielded.

8. The multi-point array detection system for surface contamination of radioactive waste liquid as described in claim 7, characterized in that: The thickness of the light-shielding aluminum film is consistent throughout, and is 200±50nm.

9. The multi-point array detection system for surface contamination of radioactive waste liquid as described in claim 8, characterized in that: The wireless communication antenna is connected to the communication protocol conversion module via the SDIO interface, and the auxiliary communication antenna is connected to the communication protocol conversion module via the UART interface.

Images