Mine waste rock nuclide activity concentration rapid detection method and device

Abstract

The invention provides a method and a device for rapidly detecting nuclide activity concentration of mine barren rock, and relates to the technical field of nuclide detection. According to the method, the total dose rate of each detection point is detected when the to-be-detected mine waste rock passes through the gate-type channel, the dose rate equation set is constructed in combination with the preset dose rate conversion coefficient of each decay system nuclide, the dose rate equation set is combined for solving, and the activity concentration of each decay system nuclide in the mine waste rock is obtained. Rapid detection of the activity concentration of the nuclide in the mine barren rock is realized, and the detection efficiency of nuclide detection in the mine barren rock is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclide detection, and in particular to a method and device for quickly detecting the activity concentration of nuclides in mine waste rock. Background Art

[0002] The use of waste rock in the field of building materials 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 rock often contains natural radionuclides, 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 established strict control standards for the activity concentration of radionuclides in building materials. At the same time, the current standards stipulate that the activity concentration of a single nuclide in the uranium (thorium) decay series must not exceed 1Bq / g, otherwise it must be treated and disposed of as radioactive waste.

[0003] Before waste rock can be used as a building material, its radionuclide activity concentration must be rigorously tested, especially for waste rock produced by companies producing associated radioactive ores. While traditional spectrometer testing provides accurate results, it requires complex sample preparation and a monitoring cycle of 18 to 30 days, which significantly increases operating costs and requires the construction of large waste rock dumps to store the waste rock.

[0004] To effectively manage this waste rock, radioactivity levels in the waste rock generated during mining must be monitored. According to national standards, the exempt concentration for natural radionuclides is 1 Bq / g. Waste rock that meets the exemption level can be regularly transported for comprehensive utilization. However, waste rock exceeding the exemption level must be strictly managed as radioactive solid waste.

[0005] However, the current method for determining the activity concentration of natural radionuclides in waste rock, such as taking samples on site and sending them to the laboratory for gamma spectrum analysis, although the analysis items are comprehensive, the scope is wide and the results are accurate, has disadvantages such as cumbersome sample preparation process and long measurement and analysis time, which makes it difficult to meet the demand for real-time and rapid determination of whether the waste rock has reached the exemption level. Summary of the Invention

[0006] The present invention provides a method and device for rapid detection of nuclide activity concentration in mine waste rock, which can realize rapid detection of nuclide activity concentration in mine waste rock and improve the detection efficiency of nuclide detection in mine waste rock.

[0007] In a first aspect, the present invention provides a method for rapid detection of activity concentration of nuclides in mine waste rock, the method comprising: obtaining the total dose rate of each detection point when the mine waste rock to be tested passes through a portal; constructing a dose rate equation group based on the total dose rate of each detection point and a preset dose rate conversion coefficient of each decay series nuclide, wherein the equation of each detection point in the dose rate equation group is the total dose rate of the detection point which is 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 absorption dose rate of the nuclide at the measurement point at unit activity concentration; solving the dose rate equation group 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 a possible implementation, based on the total dose rate of each detection point and the preset dose rate conversion coefficient of each decay series nuclide, a dose rate equation group is constructed, including: constructing a dose rate equation group based on the following formula;

[0009]

[0010] Among them, D i is the total dose rate at the i-th detection point, α i is the dose rate conversion coefficient of thorium series nuclides at the i-th detection point, β i is the dose rate conversion coefficient of uranium series nuclides at the i-th detection point, λ i is the dose rate conversion coefficient of potassium nuclide at the i-th detection point, is the activity concentration of thoron series nuclides, is the activity concentration of uranium series nuclides, is the activity concentration of potassium nuclide.

[0011] In one possible implementation, a set of simultaneous dose rate equations is solved to obtain the activity concentration of each decay series nuclide, including: obtaining multiple solutions of the set of simultaneous dose rate equations; each solution includes a set of activity concentrations of each decay series nuclide; calculating a calculated value of the total dose rate of each detection point based on the multiple solutions; calculating a comprehensive error of the dose rate corresponding to each solution of the equation based on the calculated value of the total dose rate of each detection point and the total dose rate of each detection point; determining an optimal solution of the equation based on the comprehensive error of the dose rate; and determining the activity concentration of each decay series nuclide based on the optimal solution of the equation.

[0012] In one possible implementation, the nuclide 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, then the nuclide detection result of the mine waste rock to be tested is determined to be in compliance with 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 not in compliance with 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, it also includes: if the nuclide detection result meets the exemption level, determining that the mine waste rock to be tested can be transported out; if the nuclide detection result does not meet the exemption level, determining that the mine waste rock to be tested cannot be transported out.

[0014] In one possible implementation, the portal channel includes a ground pump arranged below and a gantry arranged above the ground pump; one or more movable monitoring detectors are arranged on the gantry; during radionuclide detection, a vehicle loaded with mine waste to be tested drives into the gantry and is located above the ground pump, and 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.

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

[0016] In a second aspect, an embodiment of the present invention provides a rapid detection device for the activity concentration of nuclides in mine waste rock, the device comprising: a communication module and a processing module, the communication module being used to obtain the total dose rate of each detection point when the mine waste rock to be tested passes through a portal passage; the processing module being used to construct a dose rate equation group based on the total dose rate of each detection point and a preset dose rate conversion coefficient of each decay-series nuclide, wherein the equation of each detection point in the dose rate equation group is the total dose rate of the detection point, which is 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 absorption dose rate of the decay-series nuclide at the measurement point at unit activity concentration; the simultaneous dose rate equation group is solved to obtain the activity concentration of each decay-series nuclide; 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 simultaneously solve a set of dose rate equations to obtain multiple equation solutions; each equation solution includes a set of activity concentrations of each decay system nuclide; based on the multiple equation solutions, the calculated value of the total dose rate of each detection point is calculated; based on the calculated value of the total dose rate of each detection point and the total dose rate of each detection point, the dose rate comprehensive error corresponding to each equation solution is calculated; based on the dose rate comprehensive error, the optimal equation solution is determined; based on the optimal equation solution, the activity concentration of each decay system nuclide is determined.

[0018] In a third aspect, an embodiment of the present invention provides an electronic device comprising a memory and a processor, wherein the memory stores a computer program, and the processor is used to call and run the computer program stored in the memory to perform the steps of the method described in the first aspect and any possible implementation method of the first aspect.

[0019] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, which stores a computer program, and is characterized in that when the computer program is executed by a processor, it implements the steps of the method described in the first aspect and any possible implementation method of the first aspect.

[0020] The present invention provides a method and device for rapid detection of the activity concentration of nuclides in mining waste rock. The present invention detects the total dose rate of each detection point when the mining waste rock to be tested passes through a portal passage, and constructs a dose rate equation group in combination with preset dose rate conversion coefficients of each decay series nuclide. The simultaneous dose rate equation group is solved to obtain the activity concentration of each decay series nuclide in the mining waste rock, thereby realizing rapid detection of the activity concentration of nuclides in the mining waste rock and improving the detection efficiency of nuclides in the mining waste rock. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

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

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

[0024] Figure 3 1 is a schematic diagram of a model of the absorbed dose rate of air around a waste rock box provided by an embodiment of the present invention;

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

[0026] Figure 5 It is a structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In the following description, specific details such as particular system structures and techniques are provided for purposes of illustration, not limitation, to facilitate a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0028] In the description of the present invention, unless otherwise specified, “ / ” means “or”. For example, A / B can mean A or B. “And / or” in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, “at least one” and “a plurality of” refer to two or more. Words such as “first” and “second” do not limit the quantity and execution order, and words such as “first” and “second” do not necessarily limit them to be different.

[0029] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner to facilitate understanding.

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

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clear, the following will be described through specific embodiments in conjunction with the accompanying drawings of the present invention.

[0032] As described in the background art, the current process of nuclide detection of mining waste rock has technical problems such as complicated process, long time and low efficiency.

[0033] To solve the above technical problems, an embodiment of the present invention provides an accounting monitoring system. Figure 1 A schematic diagram of the structure of a portal channel in an accounting and monitoring system provided by an embodiment of the present invention.

[0034] In an embodiment of the present application, the portal channel includes a ground pump arranged below and a gantry arranged above the ground pump; one or more movable monitoring detectors are arranged on the gantry; during radionuclide detection, a vehicle loaded with mine waste to be tested drives into the gantry and is located above the ground pump, and 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.

[0035] In some embodiments, the portal monitoring system above the ground pump extends at least 30 cm beyond the transport vehicle bed. Monitoring probes are installed on the upper beam of the portal monitoring system, and the secondary instrument display system is located in the control room. The monitoring system probes can be moved horizontally and vertically, and can be precisely positioned according to the monitoring point setting requirements.

[0036] The portal monitoring system requires different locations to be set. There are two ways to achieve this: one is to install multiple detectors according to the required locations, and the other is to make the detectors mobile to achieve multi-point measurement. Setting up secondary instruments in the control room is a routine operation. The measurement process requires 10 data points to be measured at each location and the average is calculated.

[0037] For example, assume that the sides and bottom of the waste rock transport truck are made of sheet metal, with no cover on top. Start the software, draw a three-dimensional model, and set the calculation points. Waste rock weighing: The vehicle weighs the mass of the empty vehicle (m0) and the heavy load (mgross) at the ground pump, thereby obtaining the weight of the waste rock transported by the vehicle (mnet = mgross - m0). Average density of waste rock: The transport vehicle is generally a dump truck, that is, the sides and bottom of the truck are made of sheet metal, and the top is uncovered. Since the waste rocks transported by vehicles vary in size, it is necessary to calculate the average density of the waste rock, that is, ρ = mnet / V, where V (volume) = L (length) × W (width) × H (height) (the inner dimensions of the vehicle's bucket).

[0038] a. Set the calculation points. Draw contour lines based on the length and width of the truck bed. Then set six calculation points. Take the lower left corner as (0,0,0). The calculation points and their coordinates (not less than 30cm above the height) are as follows:

[0039] b. Waste rock parameters: define the components of waste rock and set the density of waste rock in the calculation surface, assuming the density is 1.6g / cm 3 .

[0040] c. Define U series, Th series, 40 The activity of K is based on the assumption that the activity of the parent and daughter nuclides of U and Th series in the waste rock is in equilibrium. 40 The activity of K is 1Ci (3.7×10 10 Calculate the dose rate conversion factor for each decay series or nuclide at each point.

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

[0042] like Figure 2 As shown, an embodiment of the present invention provides a method for rapid detection of radionuclide activity concentration in mine waste rock, which includes steps S101-S106.

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

[0044] S102: Constructing a dose rate equation group based on the total dose rate of each detection point and the preset dose rate conversion coefficients of each decay series nuclide.

[0045] In the embodiment of the present application, the equation for each detection point in the dose rate equation group is the total dose rate of the detection point which is 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 absorption dose rate of the nuclide at the measurement point at unit activity concentration.

[0046] Illustratively, embodiments of the present invention may construct a set of dose rate equations based on the following formulas.

[0047]

[0048] Among them, D i is the total dose rate at the i-th detection point, α i is the dose rate conversion coefficient of thorium series nuclides at the i-th detection point, β i is the dose rate conversion coefficient of uranium series nuclides at the i-th detection point, λ i is the dose rate conversion coefficient of potassium nuclide at the i-th detection point, is the activity concentration of thoron series nuclides, is the activity concentration of uranium series nuclides, is the activity concentration of potassium nuclide.

[0049] In some embodiments, the fixed-point dose rate conversion coefficient is implemented by applying software to perform modeling calculations:

[0050] ① Modeling is done based on the size of the vehicle's cargo box. The cargo box is surrounded by iron sheets and has no shielding on the top (the type of transport vehicle is generally fixed, that is, the cargo box size is fixed);

[0051] ② Input parameters: a. The inner dimensions of the truck bed, including length, width and height, are used to build a cube model; b. Input the elemental composition of the waste rock to build a waste rock material database (the elements in the waste rock of a region are not very different, so generally, the waste rock in the same place needs to be analyzed with all elements in advance as input parameters); c. Set the average density of the waste rock (usually 1.6g / cm 3 about) and air density parameters (fixed value: 0.00122g / cm 3 );

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

[0053] a. Assumptions: The natural radionuclides in waste rock are mainly U, Th and 40 Since K exists naturally, it is assumed that the daughter nuclides in the U and Th series are in equilibrium with the parent nuclides.

[0054] b. Simulation calculation: In the established model, set the U system, Th system and 40 The activity concentration of nuclides in K (this value can be set freely. Generally, the activity can be set according to the weight of the waste rock. Assuming that the weight of the waste rock in the truck bed is 1000 kg, it can be assumed that the U series, Th series and 40 K is 1000Bq respectively (including the daughter bodies of U and Th series in the setting process), then U, Th and 40 The activity concentration of K is calculated to be 1Bq / kg). Based on the set calculation points, the dose rates of different decay series nuclides at different points can be obtained (unit: nGy / h). Since the activity input of each decay series is customized, the activity concentrations of different decay series nuclides in the waste rock can be given based on the measured weight (unit: Bq / kg), thereby obtaining the dose rate conversion coefficients (nGy / h / (Bq / kg)) of the corresponding decay series nuclides at different points.

[0055] It should be noted that the principle of calculating activity concentration 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 nuclides at that location, and it is related to both distance and energy. When the distance between fixed locations is the same, only the energy is relevant. Since the gamma-ray energies of different nuclides vary, the dose rates of different decay systems at the same location will be different.

[0056] c. Error verification: Input U series, Th series and 40 The activity of K nuclide was measured, and the mircroshield software was used to calculate the integrated dose rate at fixed points and the dose rate of a single decay system at fixed points. The difference between the integrated 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 less than 5 fixed monitoring points.

[0058] e. After verification, the following calculation formula array 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 of each detection point (nGy / h), α, β, and γ represent the U series, Th series, and 40 The dose rate conversion coefficient of K (nGy / h / (Bq / kg)), δ represents the U series, Th series and 40 The activity concentration of K (Bq / kg). The relevant standards control the activity concentration of individual nuclides in the U and Th series, and neither is allowed to exceed 1000Bq / 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 a possible implementation manner, step S103 can be specifically implemented as steps S1031-S1035.

[0067] S1031. Simultaneously establish a set of dose rate equations to obtain multiple solutions.

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

[0069] S1032. Calculate the total dose rate of each detection point based on the solutions of the multiple equations.

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

[0071] S1034. Determine the optimal solution of 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. Determine 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.

[0074] For example, if the activity concentration of each decay series nuclide is less than a preset threshold, it is determined that the nuclide test result of the mine waste rock to be tested meets the exemption level;

[0075] In another exemplary embodiment, 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 not in compliance with the exemption level.

[0076] The present invention provides a method for rapidly detecting the activity concentration of nuclides in mining waste rock. The method detects the total dose rate of each detection point when the mining waste rock to be detected passes through a portal passage, and constructs a dose rate equation group in combination with preset dose rate conversion coefficients of each decay series nuclide. The simultaneous dose rate equation group is solved to obtain the activity concentration of each decay series nuclide in the mining waste rock, thereby realizing rapid detection of the activity concentration of nuclides in the mining waste rock and improving the detection efficiency of nuclides in the mining waste rock.

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

[0078] S105. If the radionuclide test results are in compliance with the exemption level, the mine waste rock to be tested is determined to be transportable.

[0079] S106. If the radionuclide test result does not meet the exemption level, the mine waste rock to be tested is determined to be unavailable for transport.

[0080] In this way, the present invention can determine whether the waste rock can be transported out through the detection of waste rock nuclides, thereby improving the utilization rate of mine waste rock.

[0081] Optionally, an embodiment of the present invention further provides a method for obtaining the total dose rate of each detection point, including steps S201-S203.

[0082] S201 : Scan a vehicle loaded with the mine waste to be tested and the mine waste to be tested to obtain a three-dimensional model of the mine waste to be tested.

[0083] S202: Determine multiple detection points based on the three-dimensional model of the mine waste rock to be detected.

[0084] S203 , controlling the detection detector to move to a plurality of detection points, and detecting the total dose rate of each of the plurality of detection points.

[0085] In this way, the embodiment of the present invention can perform three-dimensional modeling and radionuclide detection on vehicles and waste rock through the portal channel, achieve the acquisition of the total dose rate of multiple detection points, and improve the radionuclide detection speed of waste rock.

[0086] For example, a uranium mine is taken as an example to illustrate the method of the present invention.

[0087] Multi-point sampling was carried out at a uranium mine site. Samples of equal mass were taken and placed in paper sample bags. The samples were dried in an oven at 105°C. The sample particle size was required to be less than 0.074 mm. The dried samples were melted using a fusion machine. The prepared samples were analyzed using an X-ray fluorescence spectrometer. The elemental composition of the analyzed samples was used as the simulation parameter setting. The main components of the samples are shown in Table 1. The radionuclides in the samples mainly include 232 Th, 238 U. 40 K.

[0088] Table 1

[0089]

[0090] Radionuclide analysis shows that the main radionuclides in uranium waste rock come from 238 U. 235 U. 232 Th and its decay daughters and 40 K These natural radionuclides, there are three radioactive isotopes in natural uranium naturally present in the environment. 234 U. 235 U and 238 U. 238 U and 234 U each accounts for 49% of the specific activity of natural uranium and is usually taken into account in dose assessments. 238 U is the parent of the radioactive decay chain, which decays into a series of radioactive daughters, including 234 U. 230 Th, 226 Ra, 210 Pb and 210 Isotopes such as Po. 235 U, which accounts for only 1.2% of the specific activity of natural uranium, is not usually considered in dose assessments and is either ignored or, at best, estimated based on 238 U data were used to estimate the isotope ratio 235 U / 238U is about 0.04). Therefore, when calculating the activity concentration of natural radionuclides in uranium mine waste, 235 The activity concentration of U and its decay daughters is low, and their contribution to the dose level is small. Only the uranium series, thorium series and 40 K nuclide.

[0091] Model construction, using software to build a theoretical model. The model parameters are as follows: the waste rock box is a rectangular iron box with a length of 60cm, a width of 20cm, a height of 20cm, and a thickness of 0.1cm. The model diagram of the air absorption dose rate around the waste rock box is as follows: Figure 3 Measurement points 1, 2, and 3 are located at 10 cm, 20 cm, and 30 cm from the center of the box, respectively. The material composition is shown in Table 1.

[0092] The calculation method primarily utilizes the point kernel integration method, whose mathematical foundation is primarily based on the Green's function integration method, to calculate 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 for this point source is used to approximate the dose distribution in complex radiation fields. This equation accounts for the intensity and geometric position 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 mean free path length; r and r′ are the geometric positions of the gamma ray source and the point of interest, respectively.

[0095] Commonly used formulas for calculating the cumulative factor are the Taylor formula and the GP formula. This method mainly uses the Taylor formula to calculate the cumulative factor of the gamma ray dose.

[0096]

[0097] Where: A1, α1, α2 are parameters under different light source energies and different substances. When t is equal to 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] Where: n is the number of materials that the gamma ray passes through; μ i is the linear attenuation coefficient of the i-th material; T i is the length of the i-th spatial region in the rR′ direction. The point kernel integral method mainly calculates the following integral in the radiation shielding geometric space:

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

[0101] Where: V is the geometric area 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 the γ dose rate and the activity concentration of the nuclide is that when the uranium and thorium decay systems are in a decay equilibrium state, the radioactivity of the parent and daughter bodies is equal. According to the additivity of radiation dose, the air absorption dose rate at the measurement point is equivalent to 238 U. 232 The sum of the air absorption dose rates of Th and its decay daughters, 40K nuclides and the natural environmental background is expressed as follows:

[0103]

[0104] Where: D 总 is the total dose rate at the detection point, are the air absorbed dose rates of uranium series and thorium series nuclides at the detection point, for 40 K is the air absorbed dose rate at the detection point, D 本底 It is the natural environmental background, and its unit is nGy / h.

[0105] The thorium series, uranium series, 40 The air absorbed dose rate at the measurement point when the K activity concentration is 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 40 The air absorbed dose rate of unit activity concentration of K nuclide is expressed in (nGy / h) / (Bq / kg), Respectively represent the thorium series, uranium series, 40 The activity concentration of K.

[0108] The simulated air absorption dose rate of the natural radionuclide unit activity concentration in the sample is linearly related to its activity concentration. By measuring the D1, D2, and D3 values at the three detection points, we can calculate

[0109]

[0110] The above formula uses the algebraic reconstruction technique (ART). For the linear equation system Ax=b, the iterative formula of the ART algorithm is:

[0111]

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

[0113] The simulation results are obtained by MicroShield9.05 software, which can simulate the thorium series, uranium series, 40 The air absorbed dose rate at the measurement points at a K activity concentration of 1 Bq / g. The simulations assumed a uniform distribution of the waste rock sample and the radionuclides within it, and that the uranium and thorium series decay systems within the waste rock were in equilibrium. The results are shown in Table 2. By substituting the simulation results in Table 2 into the equation, the relationship between the air absorbed dose rate and the target nuclide activity concentration at the three measurement points was derived.

[0114]

[0115] Table 2

[0116] Measuring point <![CDATA[D Th ]]> <![CDATA[D U ]]> <![CDATA[D 40K ]]> 1 461.3 176.1 15.8 2 308.2 117.8 10.07 3 217.7 83.2 7.11

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

[0118] Waste rock of equal mass was taken from the site and brought back to the laboratory. Samples were prepared according to the standard sample preparation method. The waste rock samples were analyzed and tested using a GEM30-76 high-purity germanium gamma spectrometer according to the standard. 232 Th, 238 U. 40 The activity concentration of K nuclide. The measurement results are shown in Table 4.

[0119] The measured 232 Th, 238 U. 40The activity concentration of K nuclides was substituted into the formula to obtain the theoretical calculated value of air absorption dose rate and compared with the actual measured value (after deducting the background contribution). The relative deviations between the calculated results and the experimental results for the three samples were: 4.02%, 1.60%, and -4.23% for sample 1; -6.41%, -5.17%, and -7.98% for sample 2; and 3.63%, 4.16%, and 1.46% for sample 3. Considering the influence of the error, it can be considered that this method is feasible to simulate and predict the on-site air absorption dose rate of uranium mine waste rock. The main reasons for the error are as follows: (1) When the on-site model is made, the geometric shape of the model cannot be completely guaranteed to be consistent with the model constructed by simulation; (2) During the simulation process using MicroShield9.05, it is assumed that the waste rock sample and the radioactive nuclides therein are evenly distributed. During the on-site verification, the waste rock was not completely crushed into particles and could not be completely mixed evenly.

[0120] Combined with the actual measured air absorption dose rate on site, the formula was substituted and solved. The approximate solution was obtained through algebraic iteration algorithm as shown in Table 3. 238 U. 232 Th, 40 The relative deviations between the calculated and measured results of K nuclide activity concentration were within ±10%. 232 The relative deviation of Th nuclide activity concentration was 14.58%, and the others were within ±10%. 238 U. 232 The calculated results of Th nuclide activity concentration are greater than the measured results, and the calculated values are relatively conservative. 40 The activity concentration of K nuclides is not typically managed in standards. Calculation of nuclide activity concentrations employs an algebraic iteration algorithm. In actual measurements, the activity concentration of natural radionuclides in waste rock is low. Large errors in the measured air absorption dose rate can lead to significant statistical fluctuation errors, resulting in significant discrepancies between the calculated and measured activity concentrations in samples.

[0121] By comparing the calculated results of the air absorption 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 absorption dose rate of uranium mine waste rock, and the activity concentration of natural radionuclides in the sample can be calculated in combination with the actual on-site measured air absorption dose rate.

[0122] Table 3

[0123]

[0124] Table 4

[0125]

[0126] Conclusion: This study used uranium waste rock from a uranium mine as the research object. The composition of the waste rock was analyzed and used as simulation parameter settings. A theoretical model was established using MicroShield 9.05 software. The air absorption dose rate coefficients of each natural radionuclide at a unit activity concentration at the measurement point were simulated and calculated. A conversion equation between the activity concentration of the uranium waste rock sample and the absorbed dose rate was established. A field model was constructed using the theoretical model parameters, and field experiments were conducted to verify the results. The simulation results were compared with the measured results. The results showed that the relative deviation between the simulation results and the measured results did not exceed 15%, indicating that it is feasible to calculate the activity concentration of natural radionuclides in uranium waste rock using the conversion equation between the activity concentration of the uranium waste rock sample and the absorbed dose rate. This provides new ideas for the future detection of the activity concentration of natural radionuclides in uranium waste rock.

[0127] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean 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 fully described therein, reference may be made to the corresponding method embodiments described above.

[0129] Figure 4 The schematic diagram of the structure of a rapid detection device for the activity concentration of nuclides in mining 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] The communication module 301 is used to obtain the total dose rate of each detection point when the mine waste rock to be tested passes through the portal;

[0131] The processing module 302 is used to construct a dose rate equation group based on the total dose rate of each detection point and the preset dose rate conversion coefficient of each decay-related nuclide, wherein the equation of each detection point in the dose rate equation group is the weighted sum of the total dose rate of the detection point, the activity concentration of each decay-related nuclide and the dose rate conversion coefficient; the dose rate conversion coefficient is the air absorption dose rate of the decay-related nuclide at the measurement point at unit activity concentration; the simultaneous dose rate equation group is solved to obtain the activity concentration of each decay-related nuclide; based on the activity concentration of each decay-related nuclide and the preset threshold value, the nuclide detection result of the mine waste rock to be tested is determined.

[0132] Figure 5 Schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. 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, the steps in the above-mentioned method embodiments are implemented, for example Figure 2 Alternatively, when the processor 401 executes the computer program 403, the functions of the modules / units in the above-mentioned device embodiments are realized, for example, Figure 4 The functions of the communication module 301 and the processing module 302 are shown.

[0133] Exemplarily, the computer program 403 may be divided into one or more modules / units, which are stored in the memory 402 and executed by the processor 401 to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program 403 in the electronic device 400. For example, the computer program 403 may 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 (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), 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 may 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 may also be an external storage device of the electronic device 400, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the electronic device 400. Furthermore, the memory 402 may include both an internal storage unit of the electronic device 400 and an external storage device. The memory 402 is used to store the computer program and other programs and data required by the terminal. The memory 402 may also be used to temporarily store data that has been output or is about to be output.

[0136] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A method for rapid detection of radionuclide activity concentration in mine waste rock, characterized in that: include: Obtain the total dose rate at each detection point when the mine waste rock to be tested passes through the portal; Based on the total dose rate at each detection point and the preset dose rate conversion coefficients of each decay series nuclide, a dose rate equation group is constructed, wherein the equation for each detection point in the dose rate equation group is the total dose rate at the detection point, which is 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 absorption dose rate at the measurement point at unit activity concentration of the nuclide; Solve the simultaneous dose rate equations to obtain the activity concentration of each decay series nuclide; 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.

2. The method for rapid detection of nuclide activity concentration in mine waste rock according to claim 1, characterized in that: The dose rate equations are constructed based on the total dose rate of each detection point and the preset dose rate conversion coefficients of each decay series nuclide, including: Based on the following formula, the dose rate equation group is constructed; Among them, D i is the total dose rate at the i-th detection point, α i is the dose rate conversion coefficient of thorium series nuclides at the i-th detection point, β i is the dose rate conversion coefficient of uranium series nuclides at the i-th detection point, λ i is the dose rate conversion coefficient of potassium nuclide at the i-th detection point, is the activity concentration of thoron series nuclides, is the activity concentration of uranium series nuclides, is the activity concentration of potassium nuclide.

3. The method for rapid detection of nuclide activity concentration in mine waste rock according to claim 1, characterized in that: The simultaneous dose rate equations are solved to obtain the activity concentration of each decay series nuclide, including: The dose rate equations are combined to obtain multiple solutions; each solution includes a set of activity concentrations of nuclides in each decay system; Calculating a total dose rate value at each detection point based on the multiple equation solutions; Calculating the dose rate comprehensive error corresponding to each solution of the equation based on the calculated value of the total dose rate at each detection point and the total dose rate at each detection point; determining an optimal equation solution based on the dose rate comprehensive error; Based on the optimal equation solution, the activity concentration of each decay series nuclide is determined.

4. The method for rapid detection of nuclide activity concentration in mine waste rock according to claim 1, characterized in that: The determining of 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 value includes: If the activity concentration of each decay series nuclide is less than the preset threshold, it is determined that the nuclide test result of the mine waste rock to be tested meets the exemption level; If the activity concentration of any decay series nuclide is greater than or equal to the preset threshold, it is determined that the nuclide detection result of the mine waste rock to be tested does not meet the exemption level.

5. The method for rapid detection of nuclide activity concentration in mine waste rock according to claim 1, characterized in that: After determining the nuclide detection result of the mine waste rock to be tested based on the activity concentration of each decay series nuclide and the preset threshold, the method further includes: If the nuclide test result is in compliance with the exemption level, the mine waste rock to be tested is determined to be transportable; If the nuclide test result does not meet the exemption level, it is determined that the mine waste rock to be tested cannot be transported outside.

6. The method for rapid detection of nuclide activity concentration in mine waste rock according to claim 1, characterized in that: The portal passage comprises a ground pump arranged below and a gantry arranged above the ground pump; one or more movable monitoring detectors are arranged on the gantry; During radionuclide detection, a vehicle loaded with the mine waste to be tested enters the gantry and is located above the ground pump. The detection detector is controlled to move along the beam and / or column of the gantry to detect the total dose rate at each detection point.

7. The method for rapid detection of nuclide activity concentration in mine waste rock according to claim 6, characterized in that: The method for obtaining the total dose rate of each detection point includes: Scanning a 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 a plurality of detection points based on the three-dimensional model of the mine waste rock to be detected; The detection 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.

8. A rapid detection device for the activity concentration of nuclides in mine waste rock, characterized in that: include: Communication module, used to obtain the total dose rate of each detection point when the mine waste rock to be tested passes through the portal; The processing module is used to construct a dose rate equation group based on the total dose rate of each detection point and the preset dose rate conversion coefficient of each decay-related nuclide, wherein the equation of each detection point in the dose rate equation group is the total dose rate of the detection point, the weighted sum of the activity concentration of each decay-related nuclide and the dose rate conversion coefficient; the dose rate conversion coefficient is the air absorption dose rate of the decay-related nuclide at the measurement point at unit activity concentration; the simultaneous dose rate equation group is solved to obtain the activity concentration of each decay-related nuclide; based on the activity concentration of each decay-related nuclide and the preset threshold value, the nuclide detection result of the mine waste rock to be tested is determined.

9. The rapid detection device for nuclide activity concentration of mine waste rock according to claim 8, characterized in that: The processing module is specifically configured to simultaneously solve a set of dose rate equations to obtain a plurality of equation solutions; each equation solution includes a set of activity concentrations of nuclides in each decay system; based on the plurality of equation solutions, a calculated value of the total dose rate at each detection point is calculated; based on the calculated value of the total dose rate at each detection point and the total dose rate at each detection point, a dose rate integrated error corresponding to each equation solution is calculated; Based on the comprehensive error of the dose rate, an optimal equation solution is determined; based on the optimal equation solution, the activity concentration of each decay series nuclide is determined.

10. An electronic device, characterized in that: The electronic device includes 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 according to any one of claims 1 to 7.

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