Radioactive pollutant detection method
By combining laser stripping technology and detection instruments, the problem of accurately obtaining the depth and distribution of radioactive contaminants has been solved, enabling precise control of the decontamination level and minimizing waste, thereby improving the service life and economic efficiency of the facility.
Patent Information
- Application Number
- CN202510961813.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-11
- Publication Date
- 2025-10-31
AI Technical Summary
Existing technologies make it difficult to accurately determine the depth and distribution of radioactive contaminants, which may cause decontamination techniques to transfer radionuclides from one place to another, increasing waste disposal costs and damaging facilities.
By employing laser ablation technology, the distribution cross-section and depth of contaminants can be obtained by mapping the thickness of each ablation step against the contamination information. Combined with a surface contamination detector and a thickness gauge, the degree of decontamination can be precisely controlled.
It improves the accuracy of contamination depth, reduces damage to facilities, is suitable for in-situ sampling and testing, reduces testing difficulty, and enables the development of reasonable decontamination plans to minimize waste volume, thus improving economic efficiency.
Smart Images
Figure CN120871214A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of nuclear facility decontamination detection technology, and in particular to a method for detecting radioactive contaminants. Background Technology
[0002] In the nuclear fuel cycle industry, there are a large number of radioactively contaminated items. Most of these contaminants are surface contaminated. By using appropriate decontamination techniques to remove the radioactive material from the surface of the contaminants, the remaining parts can be recycled and reused. However, because radionuclides do not disappear into thin air, decontamination techniques simply transfer the radionuclides from their undesirable location to another, significantly reducing the volume of the radioactive contaminants and thus substantially lowering the cost of radioactive waste disposal. However, any decontamination technique requires a certain amount of human, material, and economic resources. Therefore, whether radioactively contaminated items need decontamination, and the thickness of the surface contaminant layer that needs to be removed, must be determined based on the surface contamination depth of the radioactive contaminants.
[0003] Before carrying out decontamination and cleaning work at nuclear facilities, it is necessary to conduct source term investigations on the objects to be decontaminated to obtain information on their contamination status. Therefore, there is an urgent need for a method that can obtain information on the degree of contamination of pollutants in order to facilitate subsequent decontamination. Summary of the Invention
[0004] In view of this, the embodiments of this application aim to provide a method for detecting radioactive pollutants, which can obtain the distribution and degree of pollution of pollutants more accurately.
[0005] To achieve the above objectives, the technical solution of this application embodiment is implemented as follows:
[0006] This application discloses a method for detecting radioactive contaminants, including:
[0007] Laser is used to peel off contaminants, and the peeling thickness and corresponding contamination information are obtained for each peeling.
[0008] Once the contamination information reaches the set condition, the peeling is stopped, and the total peeling thickness and the curves of each peeling thickness versus the corresponding contamination information are obtained.
[0009] Based on the total peeling thickness and the curve, the pollution distribution cross section and pollution depth of the pollutants are obtained.
[0010] In one embodiment, the contaminant is at least one of metal, paint, oil, coating, concrete, ceramics, and glass.
[0011] In one embodiment, the contamination information includes the concentration of radioactivity and the type of radionuclide.
[0012] In one embodiment, the set conditions are: the radioactivity concentration of alpha rays is not greater than a first preset value, and the radioactivity concentration of beta rays is not greater than a second preset value.
[0013] In one embodiment, a surface contamination detector is used to detect the contamination information, and a thickness gauge is used to measure the peeling thickness.
[0014] In one embodiment, the parameters of the laser device are adjusted to peel off the contaminant at a third preset thickness each time.
[0015] In one embodiment, the laser device is a nanosecond laser device, and the parameters of the nanosecond laser device include power, repetition rate, scanning speed, and line spacing.
[0016] In one embodiment, the third preset value is no greater than 10 μm.
[0017] In one embodiment, the detection method includes:
[0018] The surface area of the contaminant is divided into grids of a first size, and the total peeling thickness in each grid and the corresponding curve are obtained.
[0019] Based on the total peeling thickness in each grid and the corresponding curve, the pollution distribution and pollution level of the pollutants are obtained.
[0020] In one embodiment, a fixed area stripping sample is taken at the center of each grid or at the intersection of adjacent grids.
[0021] This application discloses a method for detecting radioactive contaminants. It utilizes lasers to strip the contaminants, which not only improves stripping accuracy and thus the accuracy of contamination depth, but also reduces damage to in-service facilities or facilities requiring reuse and is suitable for in-situ sampling and detection, lowering the difficulty of sampling and detection. By tracking the stripping thickness and corresponding contamination information at each step, stripping stops when the contamination information reaches a set condition, and the total stripping thickness is calculated. A curve is plotted showing the stripping thickness versus the corresponding contamination information for each step. Finally, based on the total stripping thickness and the curve, the contamination distribution cross-section and contamination depth are obtained. Thus, by acquiring the stripping thickness and corresponding contamination information after each stripping in real time, and stopping stripping when the contamination information meets the first condition, the total stripping thickness and curve are obtained. Based on the total stripping thickness and curve, the contamination distribution cross-section and contamination depth can be obtained. This allows for the assessment of the necessity and degree of subsequent decontamination, as well as the estimated amount of secondary waste to be generated. Therefore, a more reasonable decontamination plan can be formulated, the degree of decontamination can be precisely controlled, and waste can be minimized while maximizing the benefit-cost ratio, resulting in good economic efficiency. Attached Figure Description
[0022] Figure 1 This is a schematic flowchart of a method for detecting radioactive contaminants provided in an embodiment of this application. Detailed Implementation
[0023] It should be noted that, unless otherwise specified, the embodiments and technical features in the embodiments of this application can be combined with each other, and the detailed descriptions in the specific implementation should be understood as explanations of the purpose of this application and should not be regarded as undue limitations on this application.
[0024] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments. The terms "first," "second," etc., used in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly including at least one feature. In the description of the embodiments of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0025] In the nuclear fuel cycle industry, there are a large number of radioactively contaminated items. Most of these contaminants are surface contaminated. By using appropriate decontamination techniques to remove the radioactive material from the surface of the contaminants, the remaining parts can be recycled and reused. However, because radionuclides do not disappear into thin air, decontamination techniques simply transfer the radionuclides from their undesirable location to another, significantly reducing the volume of the radioactive contaminants and thus substantially lowering the cost of radioactive waste disposal. However, any decontamination technique requires a certain amount of human, material, and economic resources. Therefore, whether radioactively contaminated items need decontamination, and the thickness of the surface contaminant layer that needs to be removed, must be determined based on the surface contamination depth of the radioactive contaminants.
[0026] Among related technologies, those for detecting the surface depth of radioactive contaminants include mechanical grinding, scraping and peeling, chemical etching, and focused ion beam (FIB). Mechanical grinding and scraping and peeling methods have relatively large single-sampling depths, typically on the order of millimeters, which are insufficient for surface contamination detection. Furthermore, they leave large damaged surfaces after processing, making them unsuitable for in-service facilities or facilities requiring reuse. Chemical etching requires the use of highly corrosive chemicals to peel off the contaminant surface. This method suffers from significant peeling errors and long detection cycles, and also causes substantial damage to the contaminant surface, making it unsuitable for in-service facilities or facilities requiring reuse. Additionally, the peeling process generates radioactive and highly corrosive etching reagents that are difficult to handle. While focused ion beam technology offers high precision, it is only suitable for laboratory testing, requiring the contaminant to be moved, thus failing to meet the requirements for in-situ sampling and detection.
[0027] This application provides a method for detecting radioactive contaminants. Please refer to [link to relevant documentation]. Figure 1 The detection methods include:
[0028] S1. Use laser to peel off the contaminants and obtain the peeling thickness and corresponding contamination information for each peeling.
[0029] S2. When the contamination information reaches the set condition, stop peeling, and obtain the total peeling thickness and the curve of each peeling thickness versus the corresponding contamination information;
[0030] S3. Based on the total peeling thickness and the curve, obtain the pollution distribution cross section and pollution depth of the pollutants.
[0031] For example, the total peel thickness can be the sum of the thicknesses of each peel, while the contamination depth can be the total peel thickness.
[0032] Once the contamination information reaches the set conditions, the stripping process stops: The laser will strip the contaminant multiple times, and after each stripping, the stripping thickness and corresponding contamination information will be recorded. If the contamination information for that time meets the set conditions, the stripping will stop; otherwise, the stripping will continue.
[0033] The radioactive contaminant detection method provided in this application utilizes lasers to strip contaminants, which not only improves stripping precision and thus the accuracy of contamination depth, but also reduces damage to in-service facilities or facilities requiring reuse and is suitable for in-situ sampling and detection, reducing the difficulty of sampling and detection. By tracking the stripping thickness and corresponding contamination information at each stage, stripping stops when the contamination information reaches a set condition, and the total stripping thickness is calculated. A curve is plotted showing the stripping thickness versus the corresponding contamination information for each stage. Finally, based on the total stripping thickness and the curve, the contamination distribution cross-section and contamination depth are obtained. Thus, by acquiring the stripping thickness and corresponding contamination information after each stripping in real time, and stopping stripping when the contamination information meets the first condition, the total stripping thickness and curve are obtained. Based on the total stripping thickness and curve, the contamination distribution cross-section and contamination depth can be obtained. This allows for the assessment of the necessity and degree of subsequent decontamination, as well as the estimation of the amount of secondary waste to be generated. Therefore, a more reasonable decontamination plan can be formulated, the degree of decontamination can be precisely controlled, and waste can be minimized while maximizing the benefit-cost ratio, resulting in good economic efficiency.
[0034] For example, in one embodiment, the detection method is applied to a detection system, which includes an in-situ sampling device and a detection device. The detection device and the in-situ sampling device can be designed separately, that is, they are not connected together. The detection device can be set up independently, which can reduce the influence of the radiation environment on the detection results and improve the accuracy of the detection.
[0035] The in-situ sampling equipment includes a sampling head, a laser device, and a collection device. The sampling head has a sampling chamber and a sampling port communicating with the sampling chamber. The sampling port is used to contact the surface of the contaminant. The laser device is connected to the sampling chamber and is used to emit a laser beam towards the contaminant through the sampling port to strip the contaminant and form dust. The stripped dust is temporarily stored in the sampling chamber. The collection device is also connected to the sampling chamber and is used to collect the stripped dust in the sampling chamber. The collection device includes a vacuum pump, a sampling conduit, a collection box, and filter paper. The vacuum pump provides suction. The sampling conduit connects the vacuum pump and the sampling chamber. The collection box is located in the sampling conduit. The filter paper is placed inside the collection box and is used to collect the stripped contaminant. The detection equipment can obtain contamination information after this stripping process by detecting the collected dust.
[0036] In-situ refers to the technology of operating or testing directly in the original location or environment. Its core is to complete the processing or testing process directly in the original location without moving or transferring the object to be processed.
[0037] In one embodiment, the contaminant is at least one of metal, paint, oil, coating, concrete, ceramics, and glass.
[0038] In other words, the detection method of this application can be applied to one or more of the following: the surface of the contaminant is metallic, the surface of the contaminant is painted, the surface of the contaminant is oily, the surface of the contaminant is coated, the surface of the contaminant is concrete, the surface of the contaminant is ceramic, and the surface of the contaminant is glass. For example, the surface of the contaminant is, along its thickness, metal, concrete, and ceramic, etc. This improves flexibility and applicability.
[0039] In one embodiment, the contamination information includes the concentration of radioactivity and the type of radionuclide.
[0040] Here, by obtaining the radioactivity concentration and the types of radionuclides, the degree of contamination of the pollutant and the distribution of each radionuclide can be evaluated more comprehensively. This provides technical support for judging the necessity of decontamination of radioactive pollutants, selecting decontamination technologies, formulating and implementing decontamination plans, accurately controlling the degree of decontamination, evaluating the decontamination effect, and engineering applications. It can also provide key supporting data for research on the formation mechanism of surface contamination of pollutants and the penetration mechanism of each radionuclide.
[0041] In one embodiment, the conditions are set as follows: the radioactivity concentration of alpha rays is not greater than a first preset value, and the radioactivity concentration of beta rays is not greater than a second preset value.
[0042] For example, the first preset value can be 0.08 Bq / cm², and the second preset value can be 0.8 Bq / cm², meaning that when the radioactivity concentration of alpha rays is no greater than 0.08 Bq / cm², the radioactivity concentration is set at 0.08 Bq / cm². 2 If the radioactivity concentration of beta rays is no greater than 0.8 Bq / cm2, the contaminant can be considered to have been cleaned by the decontamination value. If it exceeds the above preset value, stripping needs to be performed again until the detected structure is no greater than the above preset value, at which point stripping can be stopped.
[0043] Here, the setting conditions are that the radioactivity concentration of alpha rays is not greater than the first preset value and the radioactivity concentration of beta rays is not greater than the second preset value. This can meet most pollution scenarios and has strong versatility.
[0044] For example, the set conditions may also include that the radioactivity concentration of gamma rays is not greater than a third preset value.
[0045] In one embodiment, a surface contamination detector is used to detect contamination information, and a thickness gauge is used to measure the peeling thickness.
[0046] Here, using a surface contamination detector to detect contamination information and a thickness gauge to measure the peeling thickness can improve the detection rate and work efficiency.
[0047] For example, in one embodiment, the aforementioned preset detection value can be the detection limit of a surface contamination detector. For instance, the first preset value can be between 0.0001 Bq / cm² and 0.01 Bq / cm² for an α-surface contamination detector. The α-surface contamination detector can also be portable, with a detection limit between 0.001 Bq / cm² and 0.01 Bq / cm². The α-surface contamination detector can also be laboratory-grade, with an even lower detection limit. It should be noted that the detection limits of β-surface contamination detectors vary considerably, with low-energy β ranging from approximately 0.1 Bq / cm² to 2 Bq / cm². 2 Between these values, the high-energy β is approximately 0.1 Bq / cm². 2 Up to 0.1 Bq / cm 2 between.
[0048] In one embodiment, the parameters of the laser device are adjusted to remove contaminants at a third preset thickness each time. This prepares the facility for subsequent quantitative detection and reduces damage to the overall integrity of the nuclear facility to some extent. This method can be applied to in-service facilities and facilities that need to be reused after decontamination, thereby extending their service life.
[0049] In one embodiment, the third preset value is no greater than 10 μm.
[0050] For example, peeling off the contaminant with a thickness not exceeding 10 μm each time means that the thickness that can be peeled off each time the laser device is activated is not greater than 10 μm, or in other words, the thickness that can be peeled off each time a laser is emitted at the contaminant after the laser device is activated is not greater than 10 μm. "Not greater than 10 μm" can be a thickness of 10 μm, 9 μm, 8 μm, 7 μm, 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, or 1 μm, etc.
[0051] Here, by using a single stripping thickness of no more than 10 μm during the sampling process, damage to the overall integrity of the nuclear facility can be reduced. This method can be applied to in-service facilities and facilities that need to be reused after decontamination, thereby improving their service life.
[0052] In one embodiment, the laser device is a nanosecond laser device, and the parameters of the nanosecond laser device include power, repetition rate, scanning speed, and line spacing.
[0053] For example, taking 304 stainless steel as the contaminant and a nanosecond laser device as the laser device, five sets of comparative experiments were conducted. The first set: power 500W, repetition rate 700kHz, scanning speed 6000mm / s, line spacing 50μm, final peel thickness 8.13μm; the second set: power 500W, repetition rate 700kHz, scanning speed 5000mm / s, line spacing 50μm, final peel thickness 11.97μm; the third set: power 500W... The first group had a repetition frequency of 700 kHz, a scan speed of 5000 mm / s, and a line spacing of 30 μm, resulting in a final peel thickness of 16.55 μm. The fourth group had a power of 500 W, a repetition frequency of 700 kHz, a scan speed of 5000 mm / s, and a line spacing of 30 μm, resulting in a final peel thickness of 20.87 μm. The fifth group had a power of 500 W, a repetition frequency of 700 kHz, a scan speed of 4000 mm / s, and a line spacing of 30 μm, resulting in a final peel thickness of 25.16 μm. From the first and second groups, as well as the fourth and fifth groups, it can be seen that, with the same power, repetition frequency, and line spacing, increasing the scan speed increases the peel thickness. From the second, third, and fourth groups, it can be seen that, with the same power, repetition frequency, and scan speed, decreasing the line spacing increases the peel thickness. Based on the aforementioned third preset value of no more than 10μm, when the contaminant is 304 stainless steel and the laser device is a nanosecond laser device, the power can be adjusted to 500W, the repetition frequency to 700kHz, the scanning speed to 6000mm / s, and the line spacing to 50μm, so that the peeling thickness can be less than 10μm.
[0054] In one embodiment, the detection method includes:
[0055] S4. Divide the surface area of the contaminant into a grid with a first size, and obtain the total peeling thickness in each grid and the corresponding curve.
[0056] S5. Based on the total peeling thickness in each grid and the corresponding curve, obtain the pollution distribution and pollution degree of the pollutants.
[0057] For example, the first size can be determined based on the surface area of the contaminant and the required detection accuracy. For instance, the first size can be 20cm×20cm or 50cm×50cm, etc.
[0058] Here, by dividing the surface of the pollutant into a grid of a first size, the total peeling thickness in each grid and the corresponding curve are obtained. Finally, based on the total peeling thickness in each grid and the corresponding curve, the pollution distribution and degree of the pollutant are obtained. This can more uniformly reflect the overall pollution distribution and degree of the pollutant, providing technical support for determining the necessity of decontamination of radioactive pollutants, selecting decontamination technologies, formulating and implementing decontamination schemes, accurately controlling the degree of decontamination, evaluating the decontamination effect, and engineering applications.
[0059] In one embodiment, a fixed area stripping sample is taken at the center of each grid or at the intersection of adjacent grids.
[0060] For example, a fixed area can be stripped and sampled at the center of each grid. The intersection of adjacent grids can be the midpoint between two adjacent grids, or the intersection of four grids arranged horizontally and vertically. The fixed area can be a circular area with a diameter of 50 mm.
[0061] Here, by performing fixed-area stripping sampling at the center of each grid or at the intersection of adjacent grids, not only is stripping sampling convenient, but subsequent data processing is also easier.
[0062] The above description is merely a preferred embodiment of this application and is not intended to limit the application. Various modifications and variations can be made to this application by those skilled in the art. All modifications, equivalent substitutions, improvements, etc., within the spirit and principles of this application are included within the scope of protection of this application.
Claims
1. A method for detecting radioactive contaminants, characterized in that, include: Laser is used to peel off contaminants, and the peeling thickness and corresponding contamination information are obtained for each peeling. Once the contamination information reaches the set condition, the peeling is stopped, and the total peeling thickness and the curves of each peeling thickness versus the corresponding contamination information are obtained. Based on the total peeling thickness and the curve, the pollution distribution cross section and pollution depth of the pollutants are obtained.
2. The detection method according to claim 1, characterized in that, The contaminant is at least one of metal, paint, oil, coating, concrete, ceramics, and glass.
3. The detection method according to claim 1, characterized in that, The pollution information includes the concentration of radioactivity and the types of radionuclides.
4. The detection method according to claim 3, characterized in that, The set conditions are: the radioactivity concentration of alpha rays is not greater than a first preset value, and the radioactivity concentration of beta rays is not greater than a second preset value.
5. The detection method according to claim 1, characterized in that, The contamination information is detected using a surface contamination detector, and the peeling thickness is measured using a thickness gauge.
6. The detection method according to claim 1, characterized in that, The parameters of the laser device are adjusted to peel off the contaminants with a thickness of the third preset value each time.
7. The detection method according to claim 6, characterized in that, The laser device is a nanosecond laser device, and the parameters of the nanosecond laser device include power, repetition rate, scanning speed, and line spacing.
8. The detection method according to claim 6, characterized in that, The third preset value is no greater than 10 μm.
9. The detection method according to claim 1, characterized in that, The detection method includes: The surface area of the contaminant is divided into grids of a first size, and the total peeling thickness in each grid and the corresponding curve are obtained. Based on the total peeling thickness in each grid and the corresponding curve, the pollution distribution and pollution level of the pollutants are obtained.
10. The detection method according to claim 9, characterized in that, A fixed area stripping sample is taken at the center of each grid or at the intersection of adjacent grids.