A method and device for rapidly detecting activity concentration of mine waste rock nuclides

Abstract

The application provides a mine waste rock nuclide activity concentration rapid detection method and device, and relates to the technical field of nuclide detection.The application detects the total dose rate of each detection point when the mine waste rock to be detected passes through the portal passage, combines with preset dose rate conversion coefficients of each decay system nuclide, constructs a dose rate equation group, solves the dose rate equation group, obtains the activity concentration of each decay system nuclide in the mine waste rock, realizes the rapid detection of the activity concentration of the nuclide in the mine waste rock, and improves the detection efficiency of the nuclide detection in the mine waste rock.

Description

Technical Field

[0001] This invention relates to the field of radionuclide detection technology, and in particular to a method and apparatus for rapid detection of radionuclide activity concentration in mine waste rock. Background Technology

[0002] The application of waste stone in the building materials field not only promotes the efficient recycling of resources but also accelerates the development of the green building materials industry, making a positive contribution to building a low-carbon, environmentally friendly, and sustainable urban environment. However, waste stone often contains naturally occurring radioactive nuclides, such as uranium (thorium) decay series nuclides and potassium-40, which pose a potential threat to the environment and human health. Therefore, the state has set strict control standards for the activity concentration of radioactive nuclides in building materials. Current standards stipulate that the activity concentration of a single nuclide in the uranium (thorium) decay series must not exceed 1 Bq / g; otherwise, it must be disposed of as radioactive waste.

[0003] Before waste rock can be used as building material, its radionuclide activity concentration must be rigorously tested, especially for waste rock generated by companies producing associated radioactive ores. While traditional spectroscopic methods can provide accurate results, the sample preparation process is complex, and the monitoring cycle can be as long as 18 to 30 days. This undoubtedly increases the operating costs of enterprises and requires the construction of large waste rock dumps to store the waste rock to be tested.

[0004] To effectively manage these waste rocks, it is necessary to test their radioactivity levels. According to national standards, the exemption concentration of naturally occurring radionuclides is 1 Bq / g. Waste rocks that meet the exemption level can be transported off-site for comprehensive utilization on a regular basis; while waste rocks that exceed the exemption standard must be strictly controlled as radioactive solid waste.

[0005] However, current methods for determining the activity concentration of natural radionuclides in waste rock, such as on-site sampling followed by gamma spectroscopy analysis in a laboratory, while comprehensive in analysis, broad in scope, and accurate in results, suffer from drawbacks such as cumbersome sample preparation and long measurement and analysis time, making it difficult to meet the need for real-time and rapid determination of whether waste rock meets the exemption level. Summary of the Invention

[0006] This invention provides a method and apparatus for rapid detection of radionuclide activity concentration in mine waste rock, which can realize rapid detection of radionuclide activity concentration in mine waste rock and improve the detection efficiency of radionuclide detection in mine waste rock.

[0007] In a first aspect, the present invention provides a rapid detection method for nuclide activity concentration in mine waste rock. The method includes: obtaining the total dose rate at each detection point when the mine waste rock to be tested passes through a portal channel; constructing a dose rate equation set based on the total dose rate at each detection point and a preset dose rate conversion coefficient for each decay series nuclide, wherein the equation for each detection point in the dose rate equation set is a weighted sum of the total dose rate at that detection point and the activity concentration of each decay series nuclide and the dose rate conversion coefficient; the dose rate conversion coefficient is the air absorbed dose rate at the measurement point when the nuclide is at a unit activity concentration; solving the dose rate equation set simultaneously to obtain the activity concentration of each decay series nuclide; and determining the nuclide detection result of the mine waste rock to be tested based on the activity concentration of each decay series nuclide and a preset threshold.

[0008] In one possible implementation, a set of dose rate equations is constructed based on the total dose rate at each detection point and the preset dose rate conversion coefficients for each decay series nuclide, including: constructing a set of dose rate equations based on the following formula;

[0009]

[0010] Among them, D i Let α be the total dose rate at the i-th detection point. i Let β be the dose rate conversion factor for thorium nuclides at the i-th detection point. i Let λ be the dose rate conversion factor of the uranium-series nuclides at the i-th detection point. i Let be the dose rate conversion factor for potassium nuclide at the i-th detection point. This represents the activity concentration of thorium-series nuclides. This represents the activity concentration of uranium-series nuclides. This represents the activity concentration of potassium nuclides.

[0011] In one possible implementation, a system of simultaneous dose rate equations is solved to obtain the activity concentration of each decay series nuclide. This includes: solving the simultaneous dose rate equations to obtain multiple solutions; each solution includes a set of activity concentrations for each decay series nuclide; calculating the total dose rate at each detection point based on the multiple solutions; calculating the combined dose rate error corresponding to each solution based on the calculated total dose rate at each detection point and the total dose rate at each detection point; determining the optimal solution based on the combined dose rate error; and determining the activity concentration of each decay series nuclide based on the optimal solution.

[0012] In one possible implementation, the radionuclide detection result of the mine waste rock to be tested is determined based on the activity concentration of each decay series nuclide and a preset threshold, including: if the activity concentration of each decay series nuclide is less than the preset threshold, the radionuclide detection result of the mine waste rock to be tested is determined to meet the exemption level; if the activity concentration of any decay series nuclide is greater than or equal to the preset threshold, the radionuclide detection result of the mine waste rock to be tested is determined to not meet the exemption level.

[0013] In one possible implementation, after determining the nuclide detection results of the mine waste rock to be tested based on the activity concentration of each decay series nuclide and a preset threshold, the method further includes: if the nuclide detection results meet the exemption level, then the mine waste rock to be tested is determined to be transportable; if the nuclide detection results do not meet the exemption level, then the mine waste rock to be tested is determined to be non-transportable.

[0014] In one possible implementation, the gantry includes a ground pump located below and a gantry frame located above the ground pump; one or more movable monitoring detectors are installed on the gantry frame; during nuclide detection, a vehicle loaded with mine waste rock to be tested drives into the gantry frame, positioned above the ground pump, and controls the detection detectors to move along the crossbeams and / or columns of the gantry frame to detect the total dose rate at each detection point.

[0015] In one possible implementation, the method for obtaining the total dose rate at each detection point includes: scanning the vehicle loaded with the mine waste rock to be tested, and the mine waste rock to be tested, to obtain a three-dimensional model of the mine waste rock to be tested; determining multiple detection points based on the three-dimensional model of the mine waste rock to be tested; controlling the detection detector to move to the multiple detection points, and detecting the total dose rate at each of the multiple detection points.

[0016] Secondly, embodiments of the present invention provide a rapid detection device for nuclide activity concentration in mine waste rock. The device includes a communication module and a processing module. The communication module is used to acquire the total dose rate at each detection point when the mine waste rock to be tested passes through a portal channel. The processing module is used to construct a dose rate equation set based on the total dose rate at each detection point and a preset dose rate conversion coefficient for each decay series nuclide. The equation for each detection point in the dose rate equation set is a weighted sum of the total dose rate at that detection point and the activity concentration of each decay series nuclide and the dose rate conversion coefficient. The dose rate conversion coefficient is the air absorbed dose rate at the measurement point when the decay series nuclide is at a unit activity concentration. The activity concentration of each decay series nuclide is obtained by simultaneously solving the dose rate equation set. Based on the activity concentration of each decay series nuclide and a preset threshold, the nuclide detection result of the mine waste rock to be tested is determined.

[0017] In one possible implementation, the processing module is specifically used to solve a set of simultaneous dose rate equations to obtain multiple solutions; each solution includes a set of activity concentrations of each decay series nuclide; based on the multiple solutions, the total dose rate at each detection point is calculated; based on the calculated total dose rate at each detection point and the total dose rate at each detection point, the dose rate comprehensive error corresponding to each solution is calculated; based on the dose rate comprehensive error, the optimal solution is determined; based on the optimal solution, the activity concentration of each decay series nuclide is determined.

[0018] Thirdly, embodiments of the present invention provide an electronic device including a memory and a processor. The memory stores a computer program, and the processor is configured to call and run the computer program stored in the memory to perform the steps of the method as described in the first aspect and any possible implementation thereof.

[0019] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing a computer program, characterized in that, when the computer program is executed by a processor, it implements the steps of the method as described in the first aspect and any possible implementation thereof.

[0020] This invention provides a rapid detection method and device for nuclide activity concentration in mine waste rock. The invention detects the total dose rate at each detection point as the mine waste rock passes through a portal channel, and constructs a set of dose rate equations by combining preset dose rate conversion coefficients for each decay series nuclide. Solving this set of equations yields the activity concentration of each decay series nuclide in the mine waste rock, thus achieving rapid detection of nuclide activity concentration in mine waste rock and improving the detection efficiency of nuclide detection in mine waste rock. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a portal channel in an accounting monitoring system provided by an embodiment of the present invention;

[0023] Figure 2 This is a flowchart illustrating a rapid detection method for radionuclide activity concentration in mine waste rock provided by an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of a model of the absorbed dose rate of air around a waste rock bin provided in an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the structure of a rapid detection device for radionuclide activity concentration in mine waste rock provided in an embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0027] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0028] In the description of this invention, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The term "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Furthermore, "at least one" and "more than one" refer to two or more. The terms "first," "second," etc., do not limit the quantity or order of execution, and "first," "second," etc., do not necessarily imply differences.

[0029] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner to facilitate understanding.

[0030] Furthermore, the terms "comprising" and "having," and any variations thereof, used in the description of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or modules is not limited to the steps or modules listed, but may optionally include other steps or modules not listed, or may optionally include other steps or modules inherent to such process, method, product, or device.

[0031] To make the objectives, technical solutions, and advantages of the present invention clearer, the following description will be provided in conjunction with the accompanying drawings and specific embodiments.

[0032] As described in the background section, the current process of radionuclide detection in mine waste rock is characterized by cumbersome procedures, long processing times, and low efficiency.

[0033] To address the aforementioned technical problems, embodiments of the present invention provide an accounting monitoring system. Figure 1 This is a schematic diagram of the structure of a portal channel in an accounting monitoring system provided by an embodiment of the present invention.

[0034] In this embodiment, the gantry includes a ground pump located below and a gantry frame located above the ground pump; one or more movable monitoring detectors are installed on the gantry frame; during nuclide detection, a vehicle loaded with mine waste rock to be tested drives into the gantry frame, positioned above the ground pump, and controls the detection detectors to move along the crossbeams and / or columns of the gantry frame to detect the total dose rate at each detection point.

[0035] In some embodiments, the gantry-type access control system above the pump is configured such that the gantry extends at least 30cm beyond the truck bed of the transport vehicle. Monitoring detectors are installed on the crossbeams of the gantry-type access control system, and the secondary instrument display system is located in the control room. The monitoring system probes are capable of lateral and longitudinal movement and can be precisely positioned according to the requirements of the monitoring point locations.

[0036] The portal monitoring system requires setting different monitoring points. There are two methods to achieve this: one is to set multiple detectors according to the requirements of each point; the other is to make the detectors mobile, enabling multi-point measurements. Setting up secondary instruments in the control room is standard procedure. During the measurement process, 10 data points are required at each point, and their average is calculated.

[0037] For example, assume the waste rock transport vehicle has a bed made of sheet metal on all sides and bottom, with no top cover. Start the software, create a 3D model, and set the calculation points. Waste rock weighing: Weigh the vehicle at the ground pump both empty (m0) and loaded (m_gross) to obtain the weight of the waste rock transported (m_net = m_gross - m0). Average waste rock density: Transport vehicles are generally dump trucks, meaning the bed is made of sheet metal on all sides and bottom, with no top cover. Since the size of the waste rock transported varies, the average density of the waste rock needs to be calculated, i.e., ρ = m_net / V, where V (volume) = L (length) × W (width) × H (height) (internal dimensions of the vehicle bed).

[0038] a. Set calculation points. Divide the contour lines according to the length and width of the truck bed, and then set six calculation points, with the lower left corner as (0,0,0). The calculation points and their coordinates (at least 30cm above the height) are as follows:

[0039] b. Waste rock parameters: Define the composition of the waste rock and set its density in the calculation surface, assuming a density of 1.6 g / cm³. 3 .

[0040] c. Define the U-series and Th-series respectively. 40 The activity of K, assuming the activity equilibrium of the parent and daughter nuclides of the U-series and Th-series in the waste rock, assuming the U-series, Th-series, 40 The activities of K were 1 Ci (i.e., 3.7 × 10⁻⁶). 10 Bq). Calculate the dose rate conversion factor for each decay system or nuclide at each site.

[0041] The dose rate conversion factor is the ratio of the dose rate obtained at the calculation point to the nuclide activity concentration in the waste rock, expressed in nGy / h / (Bq / kg). The nuclide activity concentration is the ratio of the nuclide activity to the mass of the waste rock, expressed in Bq / kg. Since the U and Th decay systems contain multiple nuclides, assuming the nuclide activity of the parent and daughter nuclides is in equilibrium, the dose rate of each decay system is the sum of the dose rates at the calculation point caused by their respective parent and daughter nuclides.

[0042] like Figure 2 As shown, this embodiment of the invention provides a rapid method for detecting the activity concentration of radionuclides in mine waste rock. The method includes steps S101-S106.

[0043] S101. Obtain the total dose rate at each detection point when the waste rock from the mine to be tested passes through the portal channel.

[0044] S102. Based on the total dose rate at each detection point and the preset dose rate conversion coefficients for each decay series nuclide, a set of dose rate equations is constructed.

[0045] In this embodiment, the equation for each detection point in the dose rate equation set is the total dose rate of the detection point being the weighted sum of the activity concentration of each decay series nuclide and the dose rate conversion coefficient; the dose rate conversion coefficient is the air absorbed dose rate at the measurement point when the nuclide is at a unit activity concentration.

[0046] For example, in embodiments of the present invention, a dose rate equation set can be constructed based on the following formula.

[0047]

[0048] Among them, D i Let α be the total dose rate at the i-th detection point. i Let β be the dose rate conversion factor for thorium nuclides at the i-th detection point. i Let λ be the dose rate conversion factor of the uranium-series nuclides at the i-th detection point. i Let be the dose rate conversion factor for potassium nuclide at the i-th detection point. This represents the activity concentration of thorium-series nuclides. This represents the activity concentration of uranium-series nuclides. This represents the activity concentration of potassium nuclides.

[0049] In some embodiments, the fixed-point dose rate conversion coefficient is implemented by using application software for modeling and calculation.

[0050] ① Model the vehicle bed according to its dimensions. The bed is surrounded by sheet metal and there is no shielding on the top (the type of transport vehicle is generally fixed, that is, the size of the bed is fixed).

[0051] ② Input parameters: a) Internal dimensions of the truck bed, including length, width, and height, to create a cubic model; b) Input the elemental composition of the waste rock to create a waste rock material database (the elemental differences in waste rock from the same area are not significant, therefore, waste rock from the same location generally requires prior elemental analysis as input parameters); c) Set the average density of the waste rock (generally 1.6 g / cm³). 3 (Left and right) and air density parameter (fixed value: 0.00122 g / cm³) 3 );

[0052] ③ Calculate the dose rate at different locations:

[0053] a. Assumptions: The natural radionuclides in the waste rock are mainly U-series, Th-series, and... 40 K, since it exists naturally, is considered to be in balance with the parent nuclide in the U and Th series.

[0054] b. Simulation calculation: In the established model, the U-series, Th-series, and... 40 The activity concentration of nuclides in K (this value can be set freely, generally based on the weight of the waste rock mentioned above; assuming the weight of the waste rock in the truck bed is 1000 kg, then the U-series, Th-series, and...) can be assumed. 40 K is 1000 Bq (including U-type and Th-type sub-entities in the setting process), then U-type, Th-type and 40 The activity concentration of K is calculated to be 1 Bq / kg. Based on the set calculation points, the dose rate (unit: nGy / h) of different decay series nuclides at different points can be obtained. Since the activity input for each decay series is user-defined, the activity concentration (unit: Bq / kg) of different decay series nuclides in the waste rock can be given based on the measured weight. Thus, the dose rate conversion coefficient (nGy / h / (Bq / kg)) of the corresponding decay series nuclides at different points can be obtained.

[0055] It should be noted that the principle behind activity concentration calculation is based on the different dose rate contributions of different nuclides at the same location. The dose rate at a fixed location is the sum of the gamma-ray energies from the decay of the nuclide at that fixed location, and it is related to both distance and energy. When the distance between fixed locations is the same, it is only related to energy. Different nuclides decay with different gamma-ray energies, therefore the dose rates of different decay systems at the same location are different.

[0056] c. Error verification: Simultaneously input U-series, Th-series, and... 40 K-nuclide activity was calculated using microshield software to determine the combined dose rate at a fixed site and the dose rate of a single decay system at the same site. The difference between the combined dose rate and the sum of the dose rates of the single decay system was analyzed to determine the accuracy of the calculated dose rate conversion coefficient, with the error controlled within 0.5%.

[0057] d. To ensure the validity of the calculation results, there should be no fewer than 5 fixed monitoring points.

[0058] e. After verification, the following array of calculation formulas is obtained:

[0059] D1=α1δ u +β1δ Th +γ1δ k

[0060] D2=α2δ u +β2δ Th +γ2δ k

[0061] D3=α3δ u +β3δ Th +γ3δ k

[0062] ………

[0063] D n =α n δ u +β n δ Th +γ n δ k

[0064] Where: D is the total dose rate (nGy / h) at each detection point, and α, β, and γ represent the U-system, Th-system, and γ-system at each point, respectively. 40 The dose rate conversion factor of K (nGy / h / (Bq / kg)), where δ represents the dose rate conversion factor of U-series, Th-series, and Th-series, respectively. 40 The activity concentration of potassium (Bq / kg). Relevant standards control the activity concentration of individual nuclides in the U and Th series, prohibiting it from exceeding 1000 Bq / kg. 40 The activity concentration of K is not controlled.

[0065] S103. Solve the simultaneous dose rate equations to obtain the activity concentration of each decay series nuclide.

[0066] As one possible implementation, step S103 can be specifically implemented as steps S1031-S1035.

[0067] S1031. By combining the dose rate equations, multiple solutions to the equations are obtained.

[0068] In some embodiments, each equation solution includes a set of activity concentrations of the nuclides in each decay series.

[0069] S1032. Based on the solutions to multiple equations, calculate the total dose rate at each detection point.

[0070] S1033. Based on the calculated total dose rate of each detection point and the total dose rate of each detection point, calculate the comprehensive dose rate error corresponding to the solution of each equation.

[0071] S1034. Determine the optimal solution to the equation based on the comprehensive error of the dose rate.

[0072] S1035. Based on the optimal equation solution, determine the activity concentration of each decay series nuclide.

[0073] S104. Based on the activity concentration of each decay series nuclide and the preset threshold, determine the nuclide detection results of the mine waste rock to be tested.

[0074] For example, if the activity concentration of each decay series nuclide is less than a preset threshold, the nuclide detection result of the mine waste rock to be tested is determined to meet the exemption level.

[0075] As another example, if the activity concentration of any decay series nuclide is greater than or equal to a preset threshold, the nuclide detection result of the mine waste rock to be tested is determined to be non-compliant with the exemption level.

[0076] This invention provides a rapid detection method for nuclide activity concentration in mine waste rock. The method involves detecting the total dose rate at each detection point as the mine waste rock passes through a portal channel, and then constructing a dose rate equation set by combining the preset dose rate conversion coefficients for each decay series nuclide. Solving this equation set yields the activity concentration of each decay series nuclide in the mine waste rock, thus achieving rapid detection of nuclide activity concentration in mine waste rock and improving the detection efficiency of nuclide detection in mine waste rock.

[0077] Optionally, the rapid detection method for nuclide activity concentration in mine waste rock provided in this embodiment of the invention further includes steps S105-S106 after step S104.

[0078] S105. If the radionuclide test results meet the exemption level, then the waste rock from the mine to be tested is determined to be transportable.

[0079] S106. If the radionuclide test result does not meet the exemption level, the waste rock from the mine to be tested is determined to be non-transportable.

[0080] Thus, this invention can determine whether waste rock can be transported off-site by detecting radionuclides in waste rock, thereby improving the utilization rate of mine waste rock.

[0081] Optionally, embodiments of the present invention also provide a method for obtaining the total dose rate at each detection point, including steps S201-S203.

[0082] S201. Scan the vehicle loaded with the waste rock to be tested, as well as the waste rock to be tested, to obtain a three-dimensional model of the waste rock to be tested.

[0083] S202. Based on the three-dimensional model of the waste rock from the mine to be tested, determine multiple detection points.

[0084] S203. Control the detector to move to multiple detection points and detect the total dose rate of each of the multiple detection points.

[0085] Thus, embodiments of the present invention can perform three-dimensional modeling and nuclide detection of vehicles and waste rock through a portal channel, thereby obtaining the total dose rate of multiple detection points and improving the speed of nuclide detection of waste rock.

[0086] For example, the method of the present invention will be described using a uranium mine as an example.

[0087] Multiple samples were collected from a uranium mine site. Equal masses of samples were placed in paper sample bags and dried in an oven at 105°C. The particle size of the samples needed to be less than 0.074 mm. The dried samples were then fused using a fusion sampler. X-ray fluorescence spectrometry was used to analyze the prepared samples, and the elemental composition was analyzed as a parameter setting for simulation. The main components of the samples are shown in Table 1. The radioactive nuclides in the samples mainly include... 232 Th、 238 U、 40 K.

[0088] Table 1

[0089]

[0090] Radionuclide analysis revealed that the main radionuclides in uranium mine waste rock originated from... 238 U、 235 U、 232 Th and its decay products and 40 These are naturally occurring radioactive nuclides. Among natural uranium, three radioactive isotopes exist naturally in the environment. 234 U、 235 U and 238 U. 238 U and 234 U accounts for 49% of the specific activity of natural uranium and is usually taken into account in dosage assessment. 238 U is the parent component of the radioactive decay chain, and its decay produces a series of radioactive daughter products, including... 234 U、 230 Th、 226 Ra、 210 Pb and 210 Isotopes such as Po. In contrast. 235 U, which accounts for only 1.2% of the specific activity of natural uranium, is generally not considered in dosage assessment; it is either ignored or, at most, determined based on... 238 Estimation of isotope ratios using U data. 235 U / 238U is approximately 0.04. Therefore, when calculating the activity concentration of naturally occurring radionuclides in uranium mine waste rock, 235 U and its decay products have low activity concentrations and contribute little to the dose level; only uranium-series and thorium-series are considered. 40 K nuclide.

[0091] Model construction: A theoretical model was built using software. The model parameters are as follows: The waste rock container is a rectangular iron box, 60cm long, 20cm wide, and 20cm high, with an iron sheet thickness of 0.1cm. A schematic diagram of the absorbed dose rate of the air around the waste rock container is shown below. Figure 3 As shown in Table 1, measurement points 1, 2, and 3 are located 10cm, 20cm, and 30cm away from the center point of the box, respectively. The material composition is shown in Table 1.

[0092] The calculation method primarily employs the point kernel integration method, which is mathematically based on the Green's function integration method for calculating the penetration behavior of neutrons and gamma rays in geometric space. By spatially discretizing the radiation source and treating it as a point source, the analytical solution of the point source is used to approximate the dose distribution in complex radiation fields. The equation considers the intensity and geometric location of the radiation source, as well as the attenuation characteristics of the shielding material.

[0093]

[0094] Where: D(r,r′,E) is the dose rate at the measurement point; C(E) is the gamma radiation flux density relative to the dose rate conversion factor; B(E,t) is the accumulation factor; t(E) is the path length of the mean free path; r and r′ are the geometric locations of the gamma-ray source and the point of interest, respectively.

[0095] The Taylor formula and the GP formula are commonly used formulas for calculating the dose accumulation factor. This method mainly uses the Taylor formula to calculate the dose accumulation factor of gamma rays.

[0096]

[0097] In the formula: A1, α1, α2 are parameters under different light source energies and different substances. When t equals 1, the distance at this time is considered to be the mean free path of the substance at this density under the light source energy.

[0098]

[0099] In the formula: n is the number of material types through which the gamma rays pass; μ i T is the linear attenuation coefficient of the i-th material; i Let rR′ be the length of the i-th spatial region. The point kernel integration method primarily calculates the following integrals in the radiation shielding geometry:

[0100] D(r)=∫ E ∫∫∫ V S·D(R,r′,E)dEdV;

[0101] In the formula: V is the geometric region where the radiation source is located; E is the energy spectrum distribution of the radiation source; S is the intensity of the radiation source.

[0102] The relationship between gamma dose rate and nuclide activity concentration is such that when the uranium and thorium decay systems are in decay equilibrium, the radioactivity of the parent and daughter nuclides is equal. According to the additivity of radiation dose, the air absorbed dose rate at the measurement point is equivalent to... 238 U、 232 The sum of the air absorbed dose rates generated by Th and its decay products, 40K nuclides, and the natural environmental background is expressed by the following formula:

[0103]

[0104] Where: D 总 The total dose rate at the detection point, These represent the air absorbed dose rates of uranium-series and thorium-series nuclides at the detection point, respectively. for 40 K is the air absorbed dose rate at the detection point, D 本底 The data represents the natural environmental background, expressed in nGy / h.

[0105] Simulations using MicroShield 9.05 software yielded results for the thorium series and uranium series. 40 The air absorbed dose rate at the measurement point for a K activity concentration of 1 Bq / g is the air absorbed dose rate per unit activity concentration of the target nuclide [(nGy / h) / (Bq / kg)]. Formula (1) can be expressed as:

[0106]

[0107] Where: α, β, and λ represent the thorium series, uranium series, and nitrogen series at the measurement point, respectively. 40 The air-absorbed dose rate per unit activity concentration of potassium nuclide, expressed in (nGy / h) / (Bq / kg). They represent the thorium series, uranium series, and uranium series at the measurement point, respectively. 40 The activity concentration of K.

[0108] The simulated air absorbed dose rate per unit activity concentration of natural radionuclides in the sample is linearly related to its activity concentration. By measuring the D1, D2, and D3 values ​​at the three detection points, the [data / information / description] can be obtained.

[0109]

[0110] The above formula employs the Algebraic Reconstruction Technique (ART) algorithm. For the linear equation system Ax = b, the iterative formula of the ART algorithm is as follows:

[0111]

[0112] in: b is the value of the j-th unknown in the k-th iteration; i It is the constant term of the i-th equation; a ij It is the element in the i-th row and j-th column of the coefficient matrix A; It is the value of the j-th unknown in the (k+1)th iteration.

[0113] Simulation results, obtained using MicroShield 9.05 software, show the thorium series, uranium series, and 40 The air absorbed dose rate at the measurement points when the K activity concentration is 1 Bq / g. In the simulation, it was assumed that the waste rock sample and its radionuclides were uniformly distributed, and that the uranium and thorium decay series in the waste rock were in decay equilibrium. The results are shown in Table 2. Substituting the simulation results from Table 2 into the formula, the relationship between the air absorbed dose rate and the target nuclide activity concentration at the three measurement points was obtained.

[0114]

[0115] Table 2

[0116] 1 461.3 176.1 15.8 2 308.2 117.8 10.07 3 217.7 83.2 7.11

[0117] Results Verification: To verify the correctness of the theoretical formula, a field verification experiment was conducted at a uranium mine. A field model was constructed based on the theoretical model parameters. Multiple samples were taken from the uranium mine's waste rock pile. The waste rock samples were crushed, mixed evenly, and placed into the field model. Multiple repeated measurements were performed at three measurement points using an FH40GNBR portable gamma dose rate meter, and the average value was taken as the final result. To ensure the repeatability and operability of the simulation calculation, the same simulation method was used to verify the three samples. The measurement results are shown in Table 3.

[0118] Waste rock of equal mass was collected from the site and brought back to the laboratory. Samples were prepared according to standard methods, and analyzed using a GEM30-76 high-purity germanium gamma spectrometer according to standards. 232 Th、 238 U、 40 The activity concentration of K nuclide was measured. The results are shown in Table 4.

[0119] The measurements obtained 232 Th、 238 U、 40Substituting the activity concentration of K nuclide into the formula to obtain the theoretically calculated air absorbed dose rate, and comparing it with the actual measured value (after deducting the background contribution), the relative deviations between the calculated and experimental results for the three samples are as follows: Sample 1: 4.02%, 1.60%, -4.23%; Sample 2: -6.41%, -5.17%, -7.98%; Sample 3: 3.63%, 4.16%, 1.46%. Considering the influence of error, it can be considered that it is feasible to simulate and predict the on-site air absorbed dose rate of uranium mine waste rock using this method. The main reasons for the error are as follows: (1) When making the on-site model, it is not possible to completely guarantee that the geometry of the model is consistent with the model constructed in the simulation; (2) In the simulation process using MicroShield 9.05, it is assumed that the waste rock sample and the radionuclides in it are uniformly distributed. However, during the on-site verification, the waste rock was not completely crushed into particles, and it could not be completely mixed uniformly.

[0120] Based on the actual air absorbed dose rate measured on-site, the formula was substituted into the solution, and an approximate solution was obtained through an algebraic iteration algorithm, as shown in Table 3. (The remaining text appears to be incomplete and requires further context.) 238 U、 232 Th、 40 The relative deviations between the calculated and measured activity concentrations of K nuclide were all within ±10%, in sample 2. 232 The relative deviation of Th nuclide activity concentration was 14.58%, while others remained within ±10%, with three samples showing the following deviations. 238 U、 232 The calculated activity concentrations of Th nuclides were all higher than the measured results, indicating that the calculated values ​​were relatively conservative. 40 The activity concentration of K nuclides is generally not regulated in standards. Algebraic iterative algorithms are used to calculate nuclide activity concentration. However, in actual measurements, the activity concentration of naturally occurring radionuclides in waste rocks is low. When there is a large error in the air absorbed dose rate measurement, significant statistical fluctuation errors occur, leading to excessive discrepancies between the calculated and measured activity concentration results in the sample.

[0121] By comparing the calculated results of the air absorbed dose rate and activity concentration in the sample with the measured results, the relative deviation is less than ±15%, indicating that this method can be used to simulate and predict the on-site air absorbed dose rate of uranium mine waste rock. Furthermore, by combining the actual on-site measured air absorbed dose rate, the activity concentration of natural radionuclides in the sample can be calculated.

[0122] Table 3

[0123]

[0124] Table 4

[0125]

[0126] In conclusion, this invention uses uranium mine waste rock as the research object, analyzes its composition as simulation parameters, and establishes a theoretical model using MicroShield 9.05 software. The model simulates and calculates the air absorbed dose rate coefficients of each natural radionuclide at a unit activity concentration at the measurement point, establishing a conversion relationship between the activity concentration and absorbed dose rate of the uranium mine waste rock sample. A field model is constructed using the theoretical model parameters, and field experiments are conducted for verification. Comparison between the simulation calculation results and the measurement results shows that the relative deviations between the simulation calculation results and the measurement results do not exceed 15%, indicating that calculating the activity concentration of natural radionuclides in uranium mine waste rock using the conversion relationship between the activity concentration and absorbed dose rate is feasible. This provides a new approach for future detection of the activity concentration of natural radionuclides in uranium mine waste rock.

[0127] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0128] The following are device embodiments of the present invention. For details not described in detail, please refer to the corresponding method embodiments described above.

[0129] Figure 4 A schematic diagram of a rapid detection device for radionuclide activity concentration in mine waste rock provided by an embodiment of the present invention is shown. The detection device 300 includes a communication module 301 and a processing module 302.

[0130] Communication module 301 is used to acquire the total dose rate of each detection point when the mine waste rock to be tested passes through the portal channel;

[0131] The processing module 302 is used to construct a set of dose rate equations based on the total dose rate at each detection point and the preset dose rate conversion coefficients for each decay series nuclide. The equation for each detection point in the dose rate equation set is a weighted sum of the total dose rate at that detection point and the activity concentration and dose rate conversion coefficient of each decay series nuclide. The dose rate conversion coefficient is the air absorbed dose rate at the measurement point when the decay series nuclide is at a unit activity concentration. The activity concentration of each decay series nuclide is obtained by solving the set of dose rate equations. Based on the activity concentration of each decay series nuclide and a preset threshold, the nuclide detection result of the mine waste rock to be tested is determined.

[0132] Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. For example... Figure 5As shown, the electronic device 400 includes: a processor 401, a memory 402, and a computer program 403 stored in the memory 402 and executable on the processor 401. When the processor 401 executes the computer program 403, it implements the steps in the above-described method embodiments, for example... Figure 2 The steps S101-S104 are shown. Alternatively, when the processor 401 executes the computer program 403, it implements the functions of each module / unit in the above-described device embodiments, for example... Figure 4 The functions of the communication module 301 and the processing module 302 shown are illustrated.

[0133] For example, the computer program 403 can be divided into one or more modules / units, which are stored in the memory 402 and executed by the processor 401 to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 403 in the electronic device 400. For example, the computer program 403 can be divided into... Figure 4 The communication module 301 and the processing module 302 are shown.

[0134] The processor 401 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0135] The memory 402 can be an internal storage unit of the electronic device 400, such as a hard disk or memory of the electronic device 400. The memory 402 can also be an external storage device of the electronic device 400, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the electronic device 400. Furthermore, the memory 402 can include both internal and external storage units of the electronic device 400. The memory 402 is used to store the computer program and other programs and data required by the terminal. The memory 402 can also be used to temporarily store data that has been output or will be output.

[0136] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A rapid method for detecting the activity concentration of radionuclides in mine waste rock, characterized in that, include: The total dose rate at each detection point is obtained when the mine waste rock to be tested passes through the portal tunnel; the portal tunnel includes a ground pump located below and a gantry frame located above the ground pump; one or more movable monitoring detectors are installed on the gantry frame; During radionuclide detection, a vehicle loaded with the mine waste rock to be tested drives into the gantry and is positioned above the ground pump. The detection detector is controlled to move along the crossbeams and / or columns of the gantry to detect the total dose rate at each detection point. Based on the total dose rate at each detection point and the preset dose rate conversion coefficients for each decay series nuclide, a set of dose rate equations is constructed. The equation for each detection point in the set of dose rate equations is the weighted sum of the total dose rate at that detection point, the activity concentration of each decay series nuclide, and the dose rate conversion coefficient. The dose rate conversion coefficient is the air absorbed dose rate at the measurement point when the nuclide is at a unit activity concentration. By solving the simultaneous dose rate equations, the activity concentrations of each decay series nuclide can be obtained. Based on the activity concentration of each decay series nuclide and a preset threshold, the nuclide detection results of the mine waste rock to be tested are determined. The method of constructing a dose rate equation set based on the total dose rate at each detection point and the preset dose rate conversion coefficients for each decay series nuclide includes: constructing a dose rate equation set based on the following formula; ； in, Let i be the total dose rate at the i-th detection point. Let be the dose rate conversion factor of thorium nuclides at the i-th detection point. Let be the dose rate conversion factor of the uranium-series nuclides at the i-th detection point. Let be the dose rate conversion factor for potassium nuclide at the i-th detection point. This represents the activity concentration of thorium-series nuclides. This represents the activity concentration of uranium-series nuclides. This represents the activity concentration of potassium nuclides.

2. The rapid detection method for radionuclide activity concentration in mine waste rock according to claim 1, characterized in that, The simultaneous dose rate equations are used to solve for the activity concentrations of each decay series nuclide, including: By combining the dose rate equations, multiple solutions are obtained; each solution includes a set of activity concentrations of each decay series nuclide. Based on the solutions to the multiple equations, the total dose rate at each detection point is calculated. Based on the calculated total dose rate of each detection point, and the total dose rate of each detection point, the comprehensive dose rate error corresponding to the solution of each equation is calculated. Based on the aforementioned dose rate comprehensive error, the optimal solution to the equation is determined; Based on the optimal equation solution, the activity concentration of each decay series nuclide is determined.

3. The rapid detection method for radionuclide activity concentration in mine waste rock according to claim 1, characterized in that, The determination of the radionuclide detection results of the mine waste rock to be tested, based on the activity concentration of each decay series nuclide and a preset threshold, includes: If the activity concentration of each decay series nuclide is less than the preset threshold, then the nuclide detection result of the mine waste rock to be tested is determined to meet the exemption level; If the activity concentration of any decay series nuclide is greater than or equal to the preset threshold, then the nuclide detection result of the mine waste rock to be tested is determined to be non-compliant with the exemption level.

4. The rapid detection method for radionuclide activity concentration in mine waste rock according to claim 1, characterized in that, After determining the radionuclide detection results of the mine waste rock to be tested based on the activity concentration of each decay series nuclide and a preset threshold, the method further includes: If the radionuclide detection result meets the exemption level, then the mine waste rock to be tested is determined to be transportable. If the radionuclide test result does not meet the exemption level, then the mine waste rock to be tested is determined to be non-transportable.

5. The rapid detection method for radionuclide activity concentration in mine waste rock according to claim 1, characterized in that, The method for obtaining the total dose rate at each detection point includes: Scan the vehicle loaded with the waste rock to be tested, as well as the waste rock to be tested, to obtain a three-dimensional model of the waste rock to be tested; Based on the three-dimensional model of the waste rock from the mine to be tested, multiple detection points are determined; The detector is controlled to move to the plurality of detection points, and the total dose rate of each of the plurality of detection points is detected.

6. A rapid detection device for nuclide activity concentration in mine waste rock, characterized in that, include: A communication module is used to acquire the total dose rate of each detection point when the mine waste rock to be tested passes through the portal tunnel; the portal tunnel includes a ground pump located below and a gantry frame located above the ground pump; one or more movable monitoring detectors are installed on the gantry frame; During radionuclide detection, a vehicle loaded with the mine waste rock to be tested drives into the gantry and is positioned above the ground pump. The detection detector is controlled to move along the crossbeams and / or columns of the gantry to detect the total dose rate at each detection point. The processing module is used to construct a set of dose rate equations based on the total dose rate at each detection point and the preset dose rate conversion coefficients for each decay series nuclide. The equation for each detection point in the dose rate equation set is a weighted sum of the total dose rate at that detection point and the activity concentration of each decay series nuclide and the dose rate conversion coefficient. The dose rate conversion coefficient is the air absorbed dose rate at the measurement point for each decay series nuclide at a unit activity concentration. The module solves for the activity concentration of each decay series nuclide by simultaneously solving the dose rate equations. Based on the activity concentration of each decay series nuclide and a preset threshold, the module determines the nuclide detection result of the mine waste rock to be tested. The method of constructing a dose rate equation set based on the total dose rate at each detection point and the preset dose rate conversion coefficients for each decay series nuclide includes: constructing a dose rate equation set based on the following formula; ； in, Let i be the total dose rate at the i-th detection point. Let be the dose rate conversion factor of thorium nuclides at the i-th detection point. Let be the dose rate conversion factor of the uranium-series nuclides at the i-th detection point. Let be the dose rate conversion factor for potassium nuclide at the i-th detection point. This represents the activity concentration of thorium-series nuclides. This represents the activity concentration of uranium-series nuclides. This represents the activity concentration of potassium nuclides.

7. The rapid detection device for radionuclide activity concentration in mine waste rock according to claim 6, characterized in that, The processing module is specifically used to solve a set of simultaneous dose rate equations to obtain multiple solutions; each solution includes a set of activity concentrations of each decay series nuclide; based on the multiple solutions, the total dose rate at each detection point is calculated; based on the total dose rate at each detection point and the total dose rate at each detection point, the dose rate comprehensive error corresponding to each solution is calculated. Based on the comprehensive error of the dose rate, the optimal solution to the equation is determined; based on the optimal solution to the equation, the activity concentration of each decay series nuclide is determined.

8. An electronic device, characterized in that, The electronic device includes a memory and a processor, the memory storing a computer program, and the processor being configured to invoke and run the computer program stored in the memory to perform the steps of the method as described in any one of claims 1 to 5.

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