Irradiator, nuclear monitoring instrument and testing method of nuclear monitoring instrument

Abstract

The invention discloses an irradiator, a nuclear monitoring instrument and a testing method of the nuclear monitoring instrument, and the irradiator comprises an irradiator body which is internally provided with a radiation source capable of emitting radiation rays; the adjustable shielding piece array is arranged in the irradiator body, the adjustable shielding piece array comprises a plurality of shielding pieces, the shielding degree of gamma rays is adjusted by increasing or decreasing the number of layers of the shielding pieces, and adjustment of the environmental dose rate is achieved; the driving mechanism is respectively connected with each shielding piece, and the driving mechanism is used for driving each shielding piece to linearly move so as to adjust the insertion layer number of the adjustable shielding piece array in the irradiator; and the irradiator control computer is used for independently regulating and controlling the intensity of a radiation field and simulating background fluctuation of an actual working condition. By increasing or decreasing the number of layers of the adjustable shielding piece array, flexible adjustment of the environmental dose rate is achieved, the limitation of a traditional fixed-strength gamma radiation field is broken through, and a dynamically changing environmental background in a real scene can be accurately matched.

Description

Technical Field

[0001] This invention relates to the field of radioactive monitoring and analysis technology, specifically to an irradiator, a nuclear monitoring instrument, and a testing method for the nuclear monitoring instrument. Background Technology

[0002] During radioactive waste disposal and nuclear facility operation, radioactive materials are transported along the process flow. Abnormalities may occur in the transport channels due to material accumulation, mechanical failure, or changes in flow characteristics, requiring timely detection and reporting of equipment operating status. Failure to issue timely alarm signals may lead to severe blockage of radioactive materials within the channels, disrupting normal processes. Actual operating conditions in transport channels are often harsh, making testing difficult. Therefore, the development of monitoring equipment necessitates the establishment of a complete simulation testing device for such radioactive material transport channels.

[0003] Currently, testing devices for monitoring the blockage of radioactive material transport channels suffer from several technical deficiencies. Traditional testing devices struggle to simulate the dynamic processes of short-segment cluster slippage or localized radioactive material accumulation during actual blockage, resulting in short-term, transient radiation signals. Existing testing devices mostly employ fixed-intensity gamma-ray reference radiation fields, which cannot be flexibly adjusted to match real-world scenarios, leading to a lack of representativeness in testing the instrument's resistance to background interference. They also lack the ability to simulate the deposition of radioactive material on the inner walls of the transport channel after long-term operation, making it difficult to verify the instrument's ability to resolve deposited radiation. Traditional testing methods cannot simulate the coupled effects of radiation signals, environmental background fluctuations, and deposition interference, resulting in insufficient comprehensive performance evaluation of the instrument. During dynamic testing, the movement of the radiation source or adjustment of the dose field may increase the risk of accidental exposure, and the shielding design of existing devices is insufficient to meet radiation safety requirements under complex testing conditions. Summary of the Invention

[0004] In view of this, the present invention provides a test method for an irradiator, a nuclear monitoring instrument, and a nuclear monitoring instrument, in order to solve the problems that existing test devices cannot be flexibly adjusted to match real-world scenarios and that the test of the instrument's resistance to background interference lacks representativeness.

[0005] In a first aspect, the present invention provides an irradiator for generating a standard gamma radiation field to simulate a dynamic environmental background dose rate, the irradiator comprising: The irradiator body has a built-in radiation source capable of emitting irradiation rays; An adjustable shielding array is disposed inside the irradiator body. The adjustable shielding array includes multiple shielding elements. By increasing or decreasing the number of shielding layers, the shielding degree of gamma rays can be adjusted to achieve the adjustment of the environmental dose rate. A drive mechanism is connected to each shielding component. The drive mechanism is used to drive each shielding component to move linearly, so as to adjust the number of insertion layers of the adjustable shielding component array inside the irradiator. An irradiator control computer is provided, with the controlled end of the drive mechanism connected to the output end of the irradiator control computer. The irradiator control computer is used to independently regulate the intensity of the radiation field and simulate background fluctuations under actual operating conditions.

[0006] The beneficial effects of the above-mentioned irradiator are as follows: by increasing or decreasing the number of layers of the adjustable shielding array, the environmental dose rate can be flexibly adjusted, breaking through the limitations of the traditional fixed intensity gamma radiation field. It can accurately match the dynamically changing environmental background in real scenarios and solve the problem that the existing test devices lack representativeness in testing the instrument's ability to resist background interference due to the fixed radiation field.

[0007] The aforementioned irradiator, relying on an irradiator control computer to independently regulate the radiation field intensity, combined with a drive mechanism to drive the shielding components to move linearly, can achieve automated and precise adjustment of the radiation field intensity, providing a controllable dynamic gamma radiation field environment for the performance verification of nuclear monitoring instruments under complex operating conditions.

[0008] The aforementioned irradiator, by simulating background fluctuations under actual operating conditions, can reproduce the complex scenario of "radiation signal + environmental background interference" in the monitoring of blockages in radioactive material transport channels. This makes the evaluation of the anti-interference capability and dynamic response performance of nuclear monitoring instruments closer to the actual operating state, and ensures that the reliability verification of the instruments in harsh environments is more thorough.

[0009] In one alternative embodiment, the drive mechanism includes a plurality of linear motors, the output of each linear motor being connected to a shield; and / or, the shield is a lead block.

[0010] Secondly, the present invention provides a nuclear monitoring instrument, comprising: A radioactive source delivery device, used to achieve three-dimensional motion control of the radioactive source; The container simulation unit is inserted and installed on the radiation source delivery device; An irradiator, located on the side of the container simulation unit, is used to provide an adjustable ambient background radiation field; Detection system, used to detect radiation signals; The control unit is connected to the radiation source delivery system, the irradiator, and the detection system, respectively.

[0011] The beneficial effects of the above technical solution are as follows: through the three-dimensional motion control of the radioactive source delivery device, complex dynamic processes such as the short-segment cluster slippage and local accumulation of radioactive materials can be accurately simulated, and short-term, transient radiation signals can be captured. This solves the problem that traditional devices cannot reproduce sudden changes in the radiation field due to insufficient fixed speed or positioning accuracy, and ensures that the response capability of nuclear monitoring instruments to transient blockage events is fully verified.

[0012] In one optional embodiment, the radiation source delivery device includes: At least one radioactive source sliding support, wherein a radioactive source slide rail is provided on the radioactive source sliding support; At least one radioactive source is disposed within a radioactive source chute via a radioactive source carrier; The radioactive source drive mechanism is connected to the radioactive source carrier and is used to drive the radioactive source carrier to slide within the radioactive source slide.

[0013] In one optional embodiment, the radiation source driving mechanism includes a pulley block, a traction rope, and a lifter. The pulley block is mounted on a mounting bracket. One end of the traction rope is connected to the radiation source carrier, and the other end of the traction rope passes around the pulley block and is connected to the lifter; and / or The radioactive source carrier is a stainless steel cylinder with a hollow spherical radioactive source placement space inside; and / or The traction rope is made of fiberglass.

[0014] In one optional embodiment, a detection system is provided on the side of the radioactive source sliding support, the detection system comprising: The collimation shield is fixedly mounted on the sliding support of the radiation source. The collimation hole of the collimator shield is set on the collimator shield, and the collimation hole of the collimator shield faces the slide of the radiation source. The detector is installed inside the collimator shield and corresponds to the collimation hole of the collimator shield.

[0015] In one optional implementation, the container simulation unit includes an equivalent container tank shell, an equivalent channel shell, and a radiation source, used to simulate container wall thickness and blockage material source items.

[0016] In one alternative embodiment, the radioactive source delivery device is disposed inside a radioactive source container, which is mounted on a mounting bracket.

[0017] Thirdly, the present invention provides a testing method for a nuclear monitoring instrument, comprising the following steps: S1. Start the irradiator to simulate the environmental background dose rate and collect the background reference value through the detection system; S2. Control the movement of the radiation source within the radiation source slide and record the dose rate change curve when there is no blockage. S3. Set up diverse source terms for actual working conditions using irradiators and radiation sources, and record detector readings; S4. By changing the intensity or position of the radioactive source, the presence of radioactive material deposits of different thicknesses / areas on the inner wall of the delivery channel is restored, thus verifying the signal suppression capability of the testing instrument against the radioactive material deposits on the inner wall; an alarm signal is triggered when the radioactivity deposited on the inner wall exceeds the alarm threshold.

[0018] In one optional implementation, in step S2, the dynamic adjustment logic for the radiation source velocity is as follows: Set the initial velocity of the radiation source; When the signal fluctuation of the detection system exceeds the first set threshold, the velocity of the radiation source is reduced to improve sampling accuracy; When the signal fluctuation of the detection system is less than the second threshold, the velocity of the radioactive source is increased to shorten the test cycle.

[0019] In one alternative implementation, the control unit executes the following algorithm: Dynamic background coupling algorithm: The ambient background dose rate output by the synchrotron irradiator and the trajectory of the radiation source generate a composite radiation field; By building this test device and testing the detector's response to the source term, multiple calibrations of the detector's sensitivity, anti-interference ability, and dynamic response can be completed simultaneously, shortening the detection cycle. Through shielding design, remote control, real-time dose rate monitoring, and door lock linkage measures, the radiation dose received by staff is ensured to be below the limit.

[0020] The technical solution of this invention has the following advantages: This invention simulates the movement and control of a radioactive source to achieve the sliding of radioactive materials, and verifies the ability of a detector to capture transient radiation signals and respond to rapidly changing radiation fields. This ensures that the instrument can accurately record the dose rate even when the radioactive source moves or experiences sudden changes, avoiding missed detections or false alarms. This testing device can be used to evaluate the detector's temporal resolution and dynamic tracking performance, providing data support for algorithm optimization.

[0021] This invention achieves high-precision reproduction of the transient process of radioactive material sliding. Traditional devices, due to large mechanical positioning errors (typically >1mm), cannot simulate the sudden changes in the radiation field caused by the local accumulation of blockages. This invention uses PLC closed-loop control to drive a servo motor, enabling the radioactive source carrier to reciprocate within the conveying channel with an accuracy of ±0.1mm, accurately reproducing the material sliding trajectory. The dynamic speed adjustment function solves the problem of transient signal capture: when the detector signal fluctuation is >10% (simulating a sudden accumulation of blockages), the system automatically reduces the speed to 0.1 m / s, increasing the sampling frequency by 5 times to ensure the capture of μs-level radiation pulses. When simulating a sudden blockage of a ceramic core (thickness ≥8cm), the speed reduction mechanism improves the dose rate decay curve resolution to 0.01s / point, reducing the false alarm rate by 92% compared to fixed-speed testing. Furthermore, the radiation resistance of the fiberglass traction rope (withstand dose >10) is improved. 6The device boasts high tensile strength (breaking load > 500N), addressing the risk of motion loss due to radiation embrittlement in traditional steel cables. Its three-dimensional motion trajectory covers the entire path from the feed hopper to the flat trough. Combined with dual drive via push rods and traction ropes, it can simulate the complex working condition of material "cluster-slippage-stagnation-secondary slippage," providing a physical basis for verifying the detector's dynamic response.

[0022] Traditional testing devices with fixed radiation fields cannot simulate the random fluctuations of the background radiation in nuclear facilities. This invention precisely matches actual operating conditions within the range of 0.1–10 Gy / h by increasing or decreasing the number of lead blocks; the irradiator control computer programmably outputs sinusoidal / step / random fluctuation signals to reproduce background changes during equipment start-up, shutdown, or accident states. Combined with a dynamic background coupling algorithm, the system synchronously adjusts the irradiator output and the trajectory of the radiation source to generate a composite radiation field. For example, when the radiation source slides at 0.3 m / s, the algorithm controls the irradiator to increase the background dose rate from 1.5 Gy / h to 4.5 Gy / h in steps within 2 seconds (simulating a sudden start-up or shutdown of nearby equipment).

[0023] To address the risk of accidental radiation exposure during dynamic testing, this design incorporates multi-dimensional protection: Primary shielding: The radiation source container is clad in 50mm lead and 5mm stainless steel to ensure a stored dose rate of <1μSv / h; Process shielding: The transport channel shield (lead equivalent ≥100mm) is combined with the collimation shield (collimation hole Ø5mm) to limit dynamic radiation leakage to 2.5μSv / h (25% of the national standard limit); Active protection: The rear cover automatically seals the channel during test intervals via a pneumatic device to block scattered radiation.

[0024] This invention achieves parallel calibration of multiple performance parameters through two core algorithms: a dynamic background coupling algorithm that synchronizes the movement of the irradiator and the radiation source in real time, generating a composite signal containing background fluctuations, material slippage, and blockage attenuation in a single test, verifying the detector's anti-interference and dynamic response capabilities; and a speed adaptive logic (signal fluctuation >10% → 0.1 m / s, <5% → 0.5 m / s) that further optimizes efficiency.

[0025] This invention restores the background radiation level corresponding to changes in actual operating conditions by adjusting the dose field intensity, providing a basis for verifying the source term monitoring and analysis of the detector under high dose rate background. The ability of the analysis instrument to distinguish between real abnormal operating conditions and environmental background fluctuations can be used to calibrate the sensitivity threshold of the instrument.

[0026] This invention modifies the intensity or location of the radioactive source to recreate radioactive material deposits of varying thicknesses and areas on the inner wall of the delivery channel, thereby verifying the signal suppression capability of testing instruments against these deposits. An alarm signal is triggered when the radioactivity deposited on the inner wall exceeds an alarm threshold. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the test principle of the present invention; Figure 2 This is a schematic diagram of the structure of the radioactive source delivery device of the present invention; Figure 3 This is a schematic diagram of the structure of the radioactive source of the present invention; Figure 4 This is a diagram showing the relative positions of the radiation source and the detector in this invention.

[0029] Explanation of reference numerals in the attached figures: 1-Radioactive source container, 2-Mounting bracket, 3-First radioactive source, 4-Second radioactive source, 5-First radioactive source sliding bracket, 6-Second radioactive source sliding bracket, 7-First radioactive source lifter, 8-Second radioactive source lifter, 9-Lifter control cabinet, 10-Test device control computer, 11-Irradiator, 12-Shielding room, 13-Irradiator control computer, 14-Upper collimator shield, 15-Upper detector, 16-Lower detector, 17-Lower collimator shield, 18 - Instrument cabinet, 21- First radioactive source lifting control device bracket, 22- First radioactive source lifting turntable, 23- Second radioactive source lifting control device bracket, 24- Second radioactive source lifting turntable, 25- Radioactive source lifting device control device, 26- Nylon rope, 27- Third radioactive source lifting turntable, 31- Upper collimator shielding collimation hole, 32- Lower collimator shielding collimation hole, 41- Radioactive source inner liner cover, 42- Radioactive source inner liner hoisting hole, 43- Silicone pad, 44- Radioactive source inner liner outer shell. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Currently, testing devices for monitoring the blockage of radioactive material transport channels suffer from several technical deficiencies. Traditional testing devices struggle to simulate the dynamic processes of short-segment cluster slippage or localized radioactive material accumulation during actual blockage, resulting in short-term, transient radiation signals. Existing testing devices mostly employ fixed-intensity gamma-ray reference radiation fields, which cannot be flexibly adjusted to match real-world scenarios, leading to a lack of representativeness in testing the instrument's resistance to background interference. They also lack the ability to simulate the deposition of radioactive material on the inner walls of the transport channel after long-term operation, making it difficult to verify the instrument's ability to resolve deposited radiation. Traditional testing methods cannot simulate the coupled effects of radiation signals, environmental background fluctuations, and deposition interference, resulting in insufficient comprehensive performance evaluation of the instrument. During dynamic testing, the movement of the radiation source or adjustment of the dose field may increase the risk of accidental exposure, and the shielding design of existing devices is insufficient to meet radiation safety requirements under complex testing conditions.

[0032] Based on this, the present invention provides a test device for a nuclear monitoring instrument for blockage of a radioactive material transport channel. As a test device for a nuclear monitoring instrument for blockage of a radioactive material transport channel, it can simulate the movement of radioactive materials in the transport channel and realize the radiation signal changes under different blockage conditions. It can accurately reproduce the background interference of the environment, flexibly adjust the radiation amount generated by the radioactive material deposited on the inner wall of the transport channel to restore the actual multi-condition operation, and has multiple safety protections to ensure the reliability verification and radiation safety management of the nuclear monitoring instrument under complex conditions.

[0033] To maximize the reproduction of the high gamma background radiation field, and taking into account the deposition of radioactive materials on the inner wall of the conveying channel during long-term operation of the equipment, a joint test of the operating conditions with multiple sources was conducted, and the speed of radioactive material movement was kept controllable, so as to reproduce the real process conditions as much as possible.

[0034] According to an embodiment of the present invention, in a first aspect, an irradiator is provided, combined with Figure 1 As shown, an irradiator used to generate a standard gamma radiation field to simulate dynamic environmental background dose rate includes an irradiator body, an adjustable shielding array, a drive mechanism, and an irradiator control computer 13. The irradiator body contains a built-in radiation source capable of emitting radiation rays. The adjustable shielding array, located inside the irradiator body, comprises multiple shielding elements. By increasing or decreasing the number of shielding layers, the shielding degree of gamma rays can be adjusted, thereby regulating the environmental dose rate. The drive mechanism is connected to each shielding element and drives each shielding element to move linearly, adjusting the number of insertion layers of the adjustable shielding array within the irradiator. The controlled end of the drive mechanism is connected to the output end of the irradiator control computer 13, which independently controls the radiation field intensity to simulate background fluctuations under actual operating conditions.

[0035] The aforementioned irradiator achieves flexible adjustment of the environmental dose rate by increasing or decreasing the number of layers of the adjustable shielding array (multiple shielding elements), breaking through the limitations of traditional fixed-intensity gamma radiation fields. It can accurately match the dynamically changing environmental background in real scenarios, solving the problem that existing testing devices lack representativeness in testing the instrument's ability to resist background interference due to the fixed radiation field.

[0036] The aforementioned irradiator, relying on the irradiator control computer 13 to independently regulate the radiation field intensity, combined with the drive mechanism to drive the shielding component to move linearly, can realize the automated and precise adjustment of the radiation field intensity, providing a controllable dynamic gamma radiation field environment for the performance verification of nuclear monitoring instruments under complex working conditions.

[0037] The aforementioned irradiator, by simulating background fluctuations under actual operating conditions, can reproduce the complex scenario of "radiation signal + environmental background interference" in the monitoring of blockages in radioactive material transport channels. This makes the evaluation of the anti-interference capability and dynamic response performance of nuclear monitoring instruments closer to the actual operating state, and ensures that the reliability verification of the instruments in harsh environments is more thorough.

[0038] In some embodiments, the driving mechanism includes multiple linear motors, each with its output terminal connected to a shielding element. In this embodiment, the axis of the output terminal of the linear motor is perpendicular to the axis of the emitted radiation light from the radiation source. Thus, when the linear motor drives the shielding element to move perpendicular to the axis of the emitted radiation light from the radiation source, the number of shielding layers can be increased or decreased. This embodiment achieves combined increases and decreases in the number of shielding layers by driving multiple linear motors. For example, when a rapid dose rate reduction is required, N motors can be driven simultaneously to insert N layers of shielding; when simulating a gradient dose field, motors at different positions can be controlled to insert different numbers of layers, such as two layers on the left and one layer on the right, forming a non-uniform radiation field.

[0039] The encoder built into the motor can provide real-time feedback on the position of the shielding component. The computer, combined with the dose rate detector data, automatically corrects the motor drive parameters to ensure the accuracy of dose rate adjustment.

[0040] In some embodiments, the shielding element is a lead block. The adjustable shielding array is an adjustable lead block array, which allows for precise adjustment of the ambient dose rate within the range of 0.1–10 Gy / h by increasing or decreasing the number of lead block layers.

[0041] The detector is one of an ionization chamber, a semiconductor detector, or a scintillator detector, and is connected to the test device control computer 10 via the instrument cabinet 18.

[0042] Traditional testing devices struggle to simulate the dynamic processes of short-segment cluster slippage or localized radioactive material accumulation during actual blockage, resulting in short-term, transient radiation signals. Traditional testing methods cannot simulate the coupled effects of multiple factors, including radiation signals, environmental background fluctuations, and deposition interference, leading to insufficient comprehensive performance evaluation of the instruments. During dynamic testing, movement of the radiation source or adjustment of the dose field may increase the risk of accidental exposure, and the shielding designs used in existing devices are insufficient to meet radiation safety requirements under complex testing conditions.

[0043] To address the aforementioned problems, according to an embodiment of the present invention, in a second aspect, a nuclear monitoring instrument is provided, which combines... Figures 1 to 4 As shown, the system includes a radioactive source delivery device, a container simulation unit, an irradiator, a detection system, and a control unit. The radioactive source delivery device is used to achieve three-dimensional motion control of the radioactive source. The container simulation unit is inserted into the radioactive source delivery device to simulate the container wall thickness and the source term of the blocking material. The irradiator is located to the side of the container simulation unit to provide an adjustable ambient background radiation field. The detection system is used to detect radiation signals. The control unit is connected to the radioactive source delivery system, the irradiator, and the detection system. The control unit, through the test device, controls the computer 10 and the electrical control cabinet to collaboratively control the movement of the radioactive source, the output of the irradiator, and data acquisition.

[0044] The instrument cabinet integrates a power distribution unit, a data acquisition unit, and an alarm output unit. The alarm threshold corresponds to a blockage thickness of ≥5cm.

[0045] In this embodiment, through the three-dimensional motion control of the radioactive source delivery device, such as the high-precision reciprocating motion and dynamic speed adjustment of the radioactive source carrier within the scanning channel, complex dynamic processes such as the slippage and local accumulation of short-segment radioactive materials can be accurately simulated, capturing short-term, transient radiation signals. For example, when the simulated blockage suddenly accumulates, causing the detector signal fluctuation to exceed 10%, the system automatically reduces its speed to 0.1 m / s to improve sampling accuracy. This solves the problem that traditional devices cannot reproduce sudden changes in the radiation field due to fixed speed or insufficient positioning accuracy, ensuring that the nuclear monitoring instrument's response capability to transient blockage events is fully verified.

[0046] This embodiment simulates the movement and control of a radioactive source to achieve the sliding of radioactive materials, and verifies the ability of a detector to capture transient radiation signals and respond to rapidly changing radiation fields. This ensures that the instrument can accurately record the dose rate even when the radioactive source moves or experiences sudden changes, avoiding missed detections or false alarms. This testing device can be used to evaluate the detector's temporal resolution and dynamic tracking performance, providing data support for algorithm optimization.

[0047] In some embodiments, the radioactive source delivery device includes a radioactive source sliding support, a radioactive source, and a radioactive source driving mechanism. At least one radioactive source sliding support is provided, and a radioactive source track is provided on the radioactive source sliding support. At least one radioactive source is provided and is disposed within the radioactive source track via a radioactive source carrier. The radioactive source driving mechanism is connected to the radioactive source carrier and is used to drive the radioactive source carrier to slide within the radioactive source track. Figure 4 As shown, the radioactive source carrier includes a radioactive source inner liner cover 41 and a radioactive source inner liner outer shell 44. The radioactive source inner liner cover 41 covers the radioactive source inner liner outer shell 44, and the radioactive source inner liner cover 41 and the radioactive source inner liner outer shell 44 form a receiving cavity, in which the radioactive source is placed. The top of the radioactive source inner liner outer shell 44 is provided with a radioactive source inner liner lifting hole 42. A silicone gasket 43 is provided between the radioactive source inner liner cover 41 and the radioactive source inner liner outer shell 44.

[0048] exist Figure 2 There are two radioactive sources: a first radioactive source 3 and a second radioactive source 4. There are also two sliding supports for the radioactive sources: a first radioactive source sliding support 5 and a second radioactive source sliding support 6. The first radioactive source sliding support 5 has a first radioactive source slide rail inside, and the second radioactive source sliding support 6 has a second radioactive source slide rail inside. The first radioactive source 3 is slidably mounted in the first radioactive source slide rail, and the second radioactive source 4 is slidably mounted in the second radioactive source slide rail.

[0049] The radioactive source drive mechanism includes a pulley block, a traction rope, and a lifter. The pulley block is mounted on the mounting bracket 2. One end of the traction rope is connected to the radioactive source carrier, and the other end passes around the pulley block and connects to the lifter. When the lifter is running, it drives the traction rope, thereby causing the radioactive source carrier and the radioactive source to move linearly. When there are two radioactive sources, there are also two lifters: a first radioactive source lifter 7 and a second radioactive source lifter 8. Both the first radioactive source lifter 7 and the second radioactive source lifter 8 are controlled by servo motors via a PLC program, with a positioning accuracy of ≤±0.1mm.

[0050] The motion control logic of the radiation source delivery device includes: the test device control computer 10 controls the radiation source lifter to drive the traction rope, which in turn drives the radiation source carrier and the radiation source to reciprocate along a set path. The scanning path covers the scanning start point, scanning interval, and scanning end point, forming a three-dimensional motion trajectory.

[0051] Furthermore, the radioactive source carrier is a stainless steel cylinder with a hollow spherical radioactive source placement position inside, and the radioactive source is placed inside the hollow spherical radioactive source placement position.

[0052] The traction rope is made of 2mm diameter fiberglass, which is radiation-resistant and tensile-resistant. During the test, the lift controls the movement of the traction rope to drive the radiation source to move linearly along the slide, thereby simulating test scenarios at different radiation source locations.

[0053] In some embodiments, a detection system is provided on the side of the radioactive source sliding support. The detection system includes a collimator shield, a collimator shield collimation hole, and a detector. The collimator shield is fixedly mounted on the radioactive source sliding support. The collimator shield collimation hole is located on the collimator shield and faces the radioactive source track. When two radioactive sources are provided, two collimator shield collimation holes are also provided, namely an upper collimator shield collimation hole 31 and a lower collimator shield collimation hole 32.

[0054] The detector is set inside the collimator shield and corresponds to the collimator aperture of the collimator shield. Only gamma rays in the radiation source slide are allowed to enter the detector through the collimator aperture, effectively filtering out interference from the dynamic background simulated by the irradiator and the container-deposited radiation.

[0055] The container simulation unit includes an equivalent container tank shell, an equivalent channel shell, and a radiation source, used to simulate container wall thickness and blockage material source terms. The equivalent container tank shell and the equivalent channel shell are made of stainless steel, with wall thickness consistent with actual operating conditions. The shielding component is a ceramic core block with a thickness of at least 2cm, 4cm, 8cm, or 10cm, which can be inserted tightly against the inner wall of the container to alter the intensity of the radiation source.

[0056] The nuclear monitoring instrument also includes a multi-layered shielding structure, comprising a radioactive source container 1, a radioactive source delivery channel shield, a radioactive source delivery device collimating shield, and a container collimating shield, forming a fully enclosed protection system. The radioactive source container 1, the radioactive source delivery channel shield, and the radioactive source delivery device collimating shield are all made of lead and covered with stainless steel. The radioactive source delivery device is housed inside the radioactive source container 1, which is mounted on a mounting bracket 2.

[0057] In some embodiments, the control module executes the following algorithm: Dynamic background coupling algorithm: The ambient background dose rate output by synchrotron irradiator 11 and the trajectory of the radiation source generate a composite radiation field.

[0058] The aforementioned nuclear monitoring instrument utilizes various source terms, including irradiators and radioactive sources, to achieve diverse source term settings under actual operating conditions, verifying the detector's data processing and logical judgment capabilities under complex conditions. By constructing this test device and testing the detector's response to source terms, multiple calibrations, such as detector sensitivity, anti-interference capability, and dynamic response, can be completed simultaneously, shortening the detection cycle. Through shielding design, remote control, real-time dose rate monitoring, and door lock linkage, measures ensure that the radiation dose received by personnel remains below the limit.

[0059] According to an embodiment of the present invention, a third aspect provides a testing method for a nuclear monitoring instrument, comprising the steps of: S1. Start the irradiator 11 to simulate the background dose rate of the environment and collect the background reference value through the detection system.

[0060] S2. Control the radioactive source to move within the radioactive source chute at a speed of 0.1–0.5 m / s, and record the dose rate change curve when there is no blockage.

[0061] In step S2, the dynamic adjustment logic for the radiation source velocity is as follows: The initial velocity of the radioactive source was set to 0.3 m / s.

[0062] When the signal fluctuation of the detection system exceeds a first set threshold, the velocity of the radiation source is reduced to improve sampling accuracy. For example, when the detector signal fluctuation is greater than 10%, the velocity is reduced to 0.1 m / s to improve sampling accuracy.

[0063] When the signal fluctuation of the detection system is less than the second threshold, the velocity of the radiation source is increased to shorten the test cycle. For example, when the detector signal fluctuation is <5%, the velocity is increased to 0.5 m / s to shorten the test cycle.

[0064] The control unit executes the following algorithm: Dynamic background coupling algorithm: The ambient background dose rate output by synchrotron irradiator 11 and the trajectory of the radiation source generate a composite radiation field.

[0065] S3. Set up diverse source terms for actual working conditions using irradiators and radiation sources, and record detector readings.

[0066] S4. By changing the intensity or position of the radioactive source, the presence of radioactive material deposits of different thicknesses / areas on the inner wall of the delivery channel is restored, thus verifying the signal suppression capability of the testing instrument against the radioactive material deposits on the inner wall; an alarm signal is triggered when the radioactivity deposited on the inner wall exceeds the alarm threshold.

[0067] This embodiment provides a test device for a radioactive material transport channel blockage monitoring instrument used in the feed section of a reprocessing dissolution equipment. The principle and process described are also applicable to the construction of test devices for other types of devices, and this invention does not limit them.

[0068] The radioactive source container is made of lead, the mounting bracket is made of stainless steel and equipped with pulleys, and the first and second radioactive source sliding brackets are made of stainless steel.

[0069] The irradiator source is an 800Ci Co-60 radioactive source, equipped with a collimation shielding device, and the collimation port is equipped with a movable lead shielding block.

[0070] The inner shell of the radioactive source is made of 5mm stainless steel, and the bottom is made of 10mm stainless steel.

[0071] The first and second radioactive source lifters are controlled by a PLC and are equipped with a turntable with a 2mm diameter nylon rope to drive the radioactive source movement.

[0072] The shielded room is a sealed laboratory with its own shielding, simulating the orange zone of actual working conditions.

[0073] The upper and lower shielding collimators are made of lead and stainless steel, which are used to reduce the interference response of the environmental background to the detector and improve the signal-to-noise ratio of the detector.

[0074] The upper and lower detectors need to be selected to realize gamma radiation. The types can be gas detectors, scintillator detectors, semiconductor detectors, etc. Since the detectors in this implementation case need to have fast response performance, an ionization chamber detector is selected for monitoring, and its acquisition circuit is designed to achieve fast response signal processing capability.

[0075] In practical applications, the aforementioned nuclear monitoring instruments: After assembling the mounting bracket 2, place it inside the shielded room 12. The constructed test bench is positioned directly opposite the irradiator 11, with the center of the mounting bracket 1.1m away from the collimation port of the irradiator. The radioactive source container 1 is fixed to the mounting bracket 2. Then, the first radioactive source sliding bracket 5 and the second radioactive source sliding bracket 6 are fixed to the mounting bracket 2. Next, the first radioactive source lifting control device bracket 21 is fixed to the first radioactive source sliding bracket 5, and the second radioactive source lifting control device bracket 23 is fixed to the second radioactive source sliding bracket 6. The radioactive source lifting control device 25 is then installed. After installing the first radioactive source lifting turntable 22, the second radioactive source lifting turntable 24, and the third radioactive source lifting turntable 27, nylon rope 26 is attached to the turntables. The nylon rope 26 is used to secure the inner cover of the radioactive source and suspend it inside the first radioactive source sliding bracket 5, extending into the radioactive source container 1 to complete the assembly of the entire test bench. Install and fix the upper collimator 14 and lower collimator 17 onto the mounting bracket 2, and place the upper detector 15 and lower detector 16 inside the collimator 17 respectively. Assemble the elevator control cabinet 9 and instrument cabinet 18, complete the connection of the corresponding equipment, and turn on the power to put the equipment into power supply mode.

[0076] The irradiator control computer 13 and the test device control computer 10 are installed outside the shielded room 12 to ensure the safety of personnel during the test.

[0077] After the equipment installation was completed, the staff left the standard gamma dose field and entered the control room to begin the test.

[0078] Turn on the irradiator control computer 13 and control the 800Ci Co-60 irradiator 11 to simulate the actual working conditions, generating an environmental background dose rate of 2.4E-3Gy / h at the upper measuring point detector; use the test device control computer 10 to open the delivery channel monitoring equipment analysis software to perform environmental background testing, observe and record the total dose A2 of the upper detector 15 within the same measurement time period of 10s.

[0079] The radiation source lifting control software of the test device control computer 10 is turned on, and the first radiation source lifter 7 is controlled to move the first radiation source 600mCi of Co-60 and stop at the upper port of the first radiation source sliding support 5. The first radiation source 3 slides down in the first radiation source sliding support 5 at a speed of 0.5m / s to pass through the collimation hole section of the upper collimation shield 14 and finally slides down into the radiation source container 1. The sliding source term test is performed by the transport channel monitoring equipment analysis software of the test device control computer 10, and the total dose A3 of the upper detector 15 in the same measurement time period of 10s is observed and recorded.

[0080] After the source term slip test is completed, an environmental background test is performed. The total dose A4 of the detector 15 above within the same measurement time period of 10 seconds is observed and recorded. By analyzing and judging A2, A3, and A4, the detector gives a background response test and a signal of source term slip capture. The two background tests before and after the source term slip are completed to determine whether there is radioactive material deposition in the delivery channel.

[0081] Turn on the irradiator control computer 13 and control the 800Ci Co-60 irradiator 11 to simulate the actual working conditions at the upper measuring point detector, generating an environmental background dose rate of 2.4E-3Gy / h. Turn on the radioactive source lifting control software of the test device control computer 10 and control the second radioactive source lifter 8 to move the second radioactive source 4600mCi Co-60 to face and stop at the collimation hole 31 of the collimator shield above the second radioactive source sliding support 6, simulating a dose rate of 1.26Gy / h of radioactive material deposited in the delivery channel. Use the test device control computer 10 to turn on the delivery channel monitoring equipment analysis software to analyze the response of the upper detector 15 when there is environmental background and radioactive material deposited in the delivery channel. Observe and record the total dose A5 of the upper detector 15 within the same measurement time period of 10s.

[0082] The radioactive source lifting control software of the test device control computer 10 is opened, and the first radioactive source lifter 7 is controlled to move the first radioactive source 3600mCi of Co-60 and stop at the upper port of the first radioactive source sliding support 5. The first radioactive source 3 slides down in the first radioactive source sliding support 5 at a speed of 0.5m / s to pass through the collimation hole range of the upper collimation shield 14, and finally slides down into the radioactive source container 1. The slide source term test is performed by the transport channel monitoring equipment analysis software of the test device control computer 10. The total dose A6 of the upper detector 15 in the same measurement time period of 10s is observed and recorded. The position of the second radioactive source 4 in its support can change the amount of radioactive material deposited in the transport channel. Through the analysis and judgment of A5 and A6 data, the detector gives a complex background response test and completes the capture of the source term slide signal when a complex background exists.

[0083] After the experiment was completed, the irradiator 11 was turned off, and the first radioactive source 3 and the second radioactive source 4 were both moved to the radioactive source container 1.

[0084] In summary, the testing device for monitoring radioactive material transport channel blockage provided by this invention offers a simulation method for radiation monitoring in complex environments. It can reproduce the motion control of various complex source terms and intricate environments, realistically approximating actual working conditions. It provides laboratory environment testing for R&D and experimental workers, while also incorporating multiple safety measures to ensure the safety of personnel.

[0085] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. An irradiator, characterized in that, The irradiator, used to generate a standard gamma radiation field to simulate dynamic environmental background dose rates, includes: The irradiator body has a built-in radiation source capable of emitting irradiation rays; An adjustable shielding array is disposed inside the irradiator body. The adjustable shielding array includes multiple shielding elements. By increasing or decreasing the number of shielding layers, the shielding degree of gamma rays can be adjusted to achieve the adjustment of the environmental dose rate. A drive mechanism is connected to each shielding component. The drive mechanism is used to drive each shielding component to move linearly, so as to adjust the number of insertion layers of the adjustable shielding component array inside the irradiator. Irradiator control computer (13), the controlled end of the drive mechanism is connected to the output end of the irradiator control computer (13), the irradiator control computer (13) is used to independently regulate the intensity of the radiation field and simulate the background fluctuation of the actual working condition.

2. The irradiator according to claim 1, characterized in that, The drive mechanism includes multiple linear motors, the output of each linear motor being connected to a shield; and / or, the shield is a lead block.

3. A nuclear monitoring instrument, characterized in that, include: A radioactive source delivery device, used to achieve three-dimensional motion control of the radioactive source; The container simulation unit is inserted and installed on the radiation source delivery device; The irradiator according to claim 1 or 2 is disposed on the side of the container simulation unit for providing an adjustable ambient background radiation field; Detection system, used to detect radiation signals; The control unit is connected to the radiation source delivery system, the irradiator, and the detection system, respectively.

4. The nuclear monitoring instrument according to claim 3, characterized in that, The radioactive source delivery device includes: At least one radioactive source sliding support, wherein a radioactive source slide rail is provided on the radioactive source sliding support; At least one radioactive source is disposed within a radioactive source chute via a radioactive source carrier; The radioactive source drive mechanism is connected to the radioactive source carrier and is used to drive the radioactive source carrier to slide within the radioactive source slide.

5. The nuclear monitoring instrument according to claim 4, characterized in that, The radioactive source driving mechanism includes a pulley block, a traction rope, and a lifter. The pulley block is mounted on a mounting bracket (2). One end of the traction rope is connected to the radioactive source carrier, and the other end of the traction rope passes around the pulley block and is connected to the lifter; and / or The radioactive source carrier is a stainless steel cylinder with a hollow spherical radioactive source placement space inside; and / or The traction rope is made of fiberglass.

6. The nuclear monitoring instrument according to claim 4, characterized in that, A detection system is provided on the side of the sliding support for the radioactive source, and the detection system includes: The collimation shield is fixedly mounted on the sliding support of the radiation source. The collimation hole of the collimator shield is set on the collimator shield, and the collimation hole of the collimator shield faces the slide of the radiation source. The detector is installed inside the collimator shield and corresponds to the collimation hole of the collimator shield.

7. The nuclear monitoring instrument according to claim 3, characterized in that, The container simulation unit includes an equivalent container tank shell, an equivalent channel shell, and a radiation source, used to simulate container wall thickness and blockage material source terms.

8. The nuclear monitoring instrument according to claim 3, characterized in that, The radioactive source delivery device is installed inside the radioactive source container (1), and the radioactive source container (1) is installed on the mounting bracket (2).

9. A testing method for a nuclear monitoring instrument, using the nuclear monitoring instrument as described in any one of claims 3-8, characterized in that, Including the following steps: S1. Start the irradiator (11) to simulate the environmental background dose rate and collect the background reference value through the detection system; S2. Control the movement of the radiation source within the radiation source slide and record the dose rate change curve when there is no blockage. S3. Set up diverse source terms for actual working conditions using irradiators and radiation sources, and record detector readings; S4. By changing the intensity or position of the radioactive source, the presence of radioactive material deposits of different thicknesses / areas on the inner wall of the delivery channel is restored, thus verifying the signal suppression capability of the testing instrument against the radioactive material deposits on the inner wall; an alarm signal is triggered when the radioactivity deposited on the inner wall exceeds the alarm threshold.

10. The testing method for the nuclear monitoring instrument according to claim 9, characterized in that, In step S2, the dynamic adjustment logic for the radiation source velocity is as follows: Set the initial velocity of the radiation source; When the signal fluctuation of the detection system exceeds the first set threshold, the velocity of the radiation source is reduced to improve sampling accuracy; When the signal fluctuation of the detection system is less than the second threshold, the velocity of the radioactive source is increased to shorten the test cycle.

11. The testing method for the nuclear monitoring instrument according to claim 9, characterized in that, The control unit executes the following algorithm: Dynamic background coupling algorithm: The ambient background dose rate output by the synchrotron irradiator (11) and the trajectory of the radiation source generate a composite radiation field; By building this test device and testing the detector's response to the source term, multiple calibrations of the detector's sensitivity, anti-interference ability, and dynamic response can be completed simultaneously, shortening the detection cycle. Through shielding design, remote control, real-time dose rate monitoring, and door lock linkage measures, the radiation dose received by staff is ensured to be below the limit.

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