Method for detecting nuclide release amount of radioactive pipeline in cutting process

Abstract

The invention relates to the technical field of nuclear facility environment evaluation, in particular to a method for detecting the nuclide release amount in the cutting process of a radioactive pipeline. The detection method comprises the following steps: measuring the surface nuclide activity level of the radioactive pipeline; constructing a sealed measurement space around the radioactive pipeline; arranging an aerosol sampling device, and communicating a sampling port of the aerosol sampling device with the sealed measurement space to form an air loop; carrying out cutting operation on the radioactive pipeline in the sealed measurement space, and starting the aerosol sampling device to carry out aerosol sampling at the same time; determining the nuclide activity level in the collected aerosol sample; and according to the measured activity level of the nuclide on the surface of the radioactive pipeline and the activity level of the nuclide in the aerosol sample, calculating the release amount of the nuclide. According to the method for detecting the nuclide release amount of the radioactive pipeline in the cutting process, the nuclide release amount of the abandoned radioactive pipeline in the cutting process can be accurately detected.

Description

A method for detecting the amount of radionuclide released during the cutting process of a radioactive pipe. Technical Field

[0001] This application relates to the field of environmental assessment technology for nuclear facilities, and in particular to a method for detecting the amount of radionuclides released during the cutting process of a radioactive pipeline. Background Technology

[0002] Nuclear fuel cycle facilities (such as uranium conversion, enrichment, component manufacturing, and reprocessing plants) generate large quantities of metal pipes contaminated with radionuclides during operation and decommissioning. These pipes often require physical treatment such as cutting and dismantling before final disposal to meet dimensional requirements for transportation, volume reduction, or disposal. However, cutting operations can damage the structural integrity of the pipes, severely disturbing radioactive materials deposited or adsorbed on their inner walls, welds, and flange connections, causing some radionuclides to be released into the working environment in the form of aerosols or dust. If such releases are not quantitatively assessed, they pose potential internal and external radiation risks to on-site personnel and introduce uncertainty into the radiation environmental impact assessment of facility decommissioning.

[0003] Currently, radiation safety assessments for such operations typically rely on historical experience data, conservative theoretical model estimates, or extremely limited on-site monitoring. However, the estimates obtained by these methods are often overly conservative or deviate significantly from reality. The data obtained cannot accurately reflect the dynamic process and true proportion of nuclide release "from the pipe surface to the air," making it difficult to provide reliable support for real-time protective interventions and accurate dose assessments during cutting operations. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this application is to provide a method for detecting the amount of radionuclides released during the cutting process of radioactive pipes, so as to accurately detect the amount of radionuclides released during the cutting process of abandoned radioactive pipes.

[0005] To achieve the above objectives, this application provides a method for detecting the amount of radionuclide released during the cutting process of a radioactive pipeline, comprising: measuring the surface radionuclide activity level of the radioactive pipeline; constructing a sealed measurement space around the radioactive pipeline for pipeline cutting and aerosol sampling; setting up an aerosol sampling device, connecting its sampling port to the sealed measurement space to form an air circuit; performing a cutting operation on the radioactive pipeline within the sealed measurement space, while simultaneously activating the aerosol sampling device to perform aerosol sampling; measuring the radionuclide activity level in the collected aerosol sample; and calculating the radionuclide release amount based on the measured surface radionuclide activity level of the radioactive pipeline and the radionuclide activity level in the aerosol sample.

[0006] Furthermore, the specific steps for determining the surface nuclide activity level of the radioactive pipeline include: wiping and sampling multiple points at the flange interface, inner wall, and outer wall of the radioactive pipeline, and performing laboratory analysis on the samples to obtain the surface nuclide activity level of the radioactive pipeline.

[0007] Furthermore, the specific steps for determining the surface nuclide activity level of the radioactive pipeline include: wiping and sampling multiple points at the flange interface, inner wall, and outer wall of the radioactive pipeline, and performing laboratory analysis on the samples to obtain the surface nuclide activity level of the radioactive pipeline.

[0008] Furthermore, the sealed measurement space is an air tent.

[0009] Furthermore, the volume of the sealed measurement space is configured to be minimized while still meeting the activity needs of the cutting personnel.

[0010] Furthermore, the aerosol sampling device is located outside the sealed measurement space; the air circuit is formed by connecting the sealed measurement space with the sampling port and return air port of the aerosol sampling device through a pipe.

[0011] Furthermore, the aerosol sampling device is a high-flow-rate staged sampler.

[0012] Furthermore, the step of cutting the radioactive pipe within the sealed measurement space while simultaneously activating the aerosol sampling device to perform aerosol sampling is repeated at least three times.

[0013] Furthermore, the start time of aerosol sampling is synchronized with the start time of the cutting operation, and the end time of aerosol sampling is later than the end time of the cutting operation.

[0014] Furthermore, the specific steps for obtaining the surface nuclide activity level of the radioactive pipeline by wiping and sampling multiple points at the flange interface, inner wall, and outer wall of the radioactive pipeline, and conducting laboratory analysis on the samples, include: wiping and sampling multiple points at the flange interface, inner wall, and outer wall of the radioactive pipeline, conducting laboratory analysis on the samples, and taking the average value as the surface nuclide activity level of the radioactive pipeline.

[0015] Furthermore, based on the measured radionuclide activity levels on the surface of the radioactive pipe and the radionuclide activity levels in the aerosol sample, the specific steps for calculating the radionuclide release amount are as follows: Where P is the amount of nuclide released, which is dimensionless; A air A represents the radionuclide activity level in an aerosol sample, in Bq. pipe The value represents the surface nuclide activity level, expressed in Bq.

[0016] The method for detecting the release of radionuclides during the cutting process of radioactive pipes in this application constructs a complete technical chain from the determination of radionuclides on the pipe surface, cutting in a closed space, simultaneous aerosol sampling to data correlation calculation. It can directly and accurately determine the radionuclides released from the pipe surface into the air during the cutting process, providing key source term data that were previously unavailable for radiation safety assessment.

[0017] The method for detecting the amount of radionuclides released during the cutting process of radioactive pipes in this application avoids the interference caused by operations such as changing filter membranes on the aerosol concentration in the measurement space in traditional sampling methods. This ensures that the collected aerosol samples can fully and accurately reflect the radionuclide release status during the entire cutting disturbance period, and greatly reduces measurement errors.

[0018] The method for detecting the amount of radionuclide released during the cutting process of radioactive pipelines disclosed in this application provides a scientific basis for calculating the radioactivity that cutting workers may inhale. This facilitates the development of individual protection plans (such as respiratory protection levels and work time restrictions), effectively protects the health and safety of workers, and improves the level of precision in decommissioning project management.

[0019] Other features and advantages of this application will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing this application. Attached Figure Description

[0020] The accompanying drawings are provided to further understand this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof. In the drawings: Figure 1 is a flowchart illustrating the method for detecting the amount of radionuclide released during the cutting process of a radioactive pipe according to Embodiment 1 of this application; Figure 2 is a structural schematic diagram of the radioactive pipe; Figure 3 is a structural schematic diagram of the sealed measurement space; Figure 4 is a schematic diagram of the cutting and sampling operations. Detailed Implementation

[0021] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While some embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this application. It should be understood that the drawings and embodiments of this application are for illustrative purposes only and are not intended to limit the scope of protection of this application.

[0022] It should be understood that the steps described in the method embodiments of this application may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of this application is not limited in this respect.

[0023] The term "comprising" and its variations as used herein are open-ended inclusions, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the description below.

[0024] It should be noted that the terms "one" and "multiple" used in this application are illustrative rather than restrictive, and those skilled in the art should understand that, unless explicitly stated otherwise in the context, they should be understood as "one or more". "Multiple" should be understood as two or more.

[0025] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0026] Example 1 One embodiment of this application provides a method for detecting the amount of radionuclide released during the cutting process of a radioactive pipe. The method for detecting the amount of radionuclide released during the cutting process of a radioactive pipe according to this application will be described below with reference to Figures 1-4: Step S101: Determine the surface radionuclide activity level of the radioactive pipe; As shown in Figure 2, in this embodiment of the application, multiple points of wiping and sampling are performed on the flange interface, inner wall and outer wall of the radioactive pipe, and the samples are sent to the laboratory for analysis. The average value is taken as the surface radionuclide activity level of the radioactive pipe.

[0027] It should be noted that, in the embodiments of this application, the radioactive pipeline refers to a radioactive metal pipeline to be discarded. Step S102: Construct a sealed measurement space around the radioactive pipeline for pipeline cutting and aerosol sampling. In the embodiments of this application, a dedicated room or air tent with good sealing performance is used as the sealed measurement space for radioactive pipeline cutting and radionuclide release.

[0028] In this embodiment, the volume of the sealed measurement space is configured to be as small as possible while still satisfying the range of movement of the cutting operator, so as to avoid affecting the efficiency and accuracy of aerosol sampling.

[0029] Step S103: Set up an aerosol sampling device and connect its sampling port to the sealed measurement space to form an air circuit; as shown in Figure 3, in this embodiment of the application, the aerosol sampling device is set outside the sealed measurement space; the sealed measurement space is connected to the sampling port and return air port of the aerosol sampling device through a pipe to form an air circuit.

[0030] In this embodiment, the aerosol sampling device used is a high-flow-rate staged sampler, and the sampling flow rate and sampling volume are controlled during the sampling process. The sampling volume should be at least 1.5 times the sealed measurement space, and the sampling duration is recommended to be no more than half an hour. The sampling flow rate is calculated as sampling volume / sampling duration.

[0031] Step S104: Cut the radioactive pipe within the sealed measurement space, and simultaneously activate the aerosol sampling device to perform aerosol sampling; In this embodiment, after the radioactive waste metal pipe to be cut is transferred to the sealed measurement space, the cutting operator enters the sealed measurement space with cutting tools to perform the cutting operation. During the cutting operation, the sealing effect of the sealed measurement space should be ensured to be good.

[0032] As shown in Figure 4, in this embodiment, the cutting direction of the cutting operation is the same as the pipe flow direction, and the single cutting length is 1m. After the cutting operation is completed, the personnel quickly leave the sealed measurement space. The aerosol sampling operation starts simultaneously with the cutting operation, and the aerosol sampling operation ends later than the cutting operation. The sampling volume of the aerosol sampling operation is larger than the volume of the sealed measurement space.

[0033] In this embodiment of the application, to ensure the reliability of aerosol sampling data, step S104 is repeated more than three times.

[0034] Step S105: Measure the radionuclide activity level in the collected aerosol sample; In this embodiment, after the sampling operation is completed, the filter membranes of the aerosol sampling device are numbered and collected, and sent to the laboratory for analysis to measure the radionuclide activity level in the collected aerosol sample; Step S106: Calculate the radionuclide release amount based on the measured radionuclide activity level on the surface of the radioactive pipe and the radionuclide activity level in the aerosol sample; After obtaining the measured radionuclide activity level in the aerosol sample, and combining it with the surface radionuclide activity level obtained in step S101, the data is processed and calculated to obtain the radionuclide release amount during the radioactive pipe cutting process. The calculation formula is as follows: Where P is the amount of nuclide released, which is dimensionless; A air A represents the radionuclide activity level in an aerosol sample, in Bq. pipe The value represents the surface nuclide activity level, expressed in Bq.

[0035] The above description is merely a partial embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of disclosure in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

[0036] Furthermore, while the operations are described in a specific order, this should not be construed as requiring these operations to be performed in the specific order shown or in sequential order. Multitasking and parallel processing may be advantageous in certain environments. Similarly, while several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of this application. Certain features described in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0037] Although the subject matter has been described using language specific to structural features and / or methodological logic, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are merely illustrative examples of implementing the claims.

Claims

1. A method for detecting the amount of radionuclide released during the cutting process of a radioactive pipe, characterized in that, include: Determine the surface nuclide activity level of radioactive pipes; A sealed measurement space was constructed around the radioactive pipe for pipe cutting and aerosol sampling. An aerosol sampling device is set up, and its sampling port is connected to the sealed measurement space to form an air circuit; the radioactive pipe is cut inside the sealed measurement space, and the aerosol sampling device is activated to collect aerosol samples. The activity levels of radionuclides in the collected aerosol samples were measured; the amount of radionuclides released was calculated based on the measured activity levels of radionuclides on the surface of the radioactive pipe and the activity levels of radionuclides in the aerosol samples.

2. The method for detecting the amount of radionuclide released during the cutting process of a radioactive pipe according to claim 1, characterized in that, The specific steps for determining the surface nuclide activity level of the radioactive pipeline include: wiping and sampling multiple points at the flange interface, inner wall, and outer wall of the radioactive pipeline, and performing laboratory analysis on the samples to obtain the surface nuclide activity level of the radioactive pipeline.

3. The method for detecting the amount of radionuclide released during the cutting process of a radioactive pipe according to claim 2, characterized in that, The sealed measurement space is an air tent.

4. The method for detecting the amount of radionuclide released during the cutting process of a radioactive pipe according to claim 1, characterized in that, The volume of the sealed measurement space is configured to be minimized while still meeting the needs of the cutting personnel.

5. The method for detecting the amount of radionuclide released during the cutting process of a radioactive pipe according to claim 1, characterized in that, The aerosol sampling device for aerosol sampling is located outside the sealed measurement space; the air circuit is formed by connecting the sealed measurement space with the sampling port and return air port of the aerosol sampling device through a pipe.

6. The method for detecting the amount of radionuclide released during the cutting process of a radioactive pipe according to claim 1, characterized in that, The aerosol sampling device is a high-flow-rate staged sampler.

7. The method for detecting the amount of radionuclide released during the cutting process of a radioactive pipe according to claim 1, characterized in that, The step of cutting the radioactive pipe within the sealed measurement space and simultaneously activating the aerosol sampling device to perform aerosol sampling is repeated at least three times.

8. The method for detecting the amount of radionuclide released during the cutting process of a radioactive pipe according to claim 1, characterized in that, The start time of aerosol sampling is synchronized with the start time of the cutting operation, and the end time of aerosol sampling is later than the end time of the cutting operation.

9. The method for detecting the amount of radionuclide released during the cutting process of a radioactive pipe according to claim 2, characterized in that, The specific steps for obtaining the surface nuclide activity level of the radioactive pipeline by wiping and sampling multiple points at the flange interface, inner wall, and outer wall of the radioactive pipeline, and then performing laboratory analysis on the samples, include: wiping and sampling multiple points at the flange interface, inner wall, and outer wall of the radioactive pipeline, performing laboratory analysis on the samples, and taking the average value as the surface nuclide activity level of the radioactive pipeline.

10. The method for detecting the amount of radionuclide released during the cutting process of a radioactive pipe according to claim 8, characterized in that, The specific steps for calculating the amount of radionuclide released, based on the measured radionuclide activity levels on the surface of the radioactive pipe and in the aerosol samples, are as follows: Where P is the amount of nuclide released, which is dimensionless; A air A represents the radionuclide activity level in an aerosol sample, in Bq. pipe The value represents the surface nuclide activity level, expressed in Bq.

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