A method for assessing human exposure dose during decommissioning of nuclear facilities

Abstract

The present invention relates to a method for assessing human radiation dose during nuclear facility decommissioning. The method utilizes a dose assessment system, wherein the dose assessment system is used to assess the human radiation dose during nuclear facility decommissioning operations based on a three-dimensional scene model and radiation field model invoked by the system. The method is characterized in that the dose assessment method comprises the following steps: scanning the position information of the current equipment to obtain coordinate data of the currently operated equipment and operators; invoking the three-dimensional scene model and radiation field model based on the coordinate data of the operated equipment; obtaining nuclear facility disassembly and assembly information during the nuclear decommissioning operation to correct the three-dimensional scene model and radiation field model; and calculating the real-time and cumulative doses received by the operators based on the corrected radiation field model.

Description

Technical Field

[0001] The present invention relates to the field of radiation protection technology, and in particular to a method for assessing human exposure doses during decommissioning of nuclear facilities. Background Art

[0002] At present, the world's energy demand is growing, and countries including my country are vigorously promoting clean energy. Among them, nuclear energy, as a highly efficient and pollution-free energy supply method, is being adopted by more and more countries. my country's nuclear power has become a national business card, and the construction of domestic nuclear power plants is in full swing.

[0003] Nuclear power plants and related nuclear facilities contain radioactivity, posing potential hazards to humans and the environment. When working in a radioactive environment, including equipment and facility maintenance and the disassembly process during nuclear facility decommissioning, the first thing to consider is the safety and accessibility (operability) requirements of working in a radioactive environment, and real-time attention should be paid to the radiation dose to personnel. Due to the complexity of the radiation environment, the differences in the decay characteristics of different types of nuclides at different locations, and the superposition of the spatial distribution of nuclides, the radiation dose at different locations within the scene varies greatly. Therefore, the immediate and cumulative dose conditions to equipment and personnel in the radiation field are very complex.

[0004] Chinese patent publication number CN11456A discloses a method for assessing human radiation dose during nuclear facility decommissioning. Specifically, it involves a simulation method based on a point-kernel integration method that simplifies nuclear decommissioning workers into a stylized model and dynamically calculates human radiation dose. The method includes: constructing a virtual human model using a stylized model; converting key tissues in the stylized model into a series of detection points; calculating the equivalent dose at these key tissue detection points using a point-kernel integration method; and calculating the effective dose of the virtual human at the end of decommissioning activities, thereby enabling assessment of worker radiation dose during the decommissioning process. The method includes three modules: decommissioning environment modeling, stylized human model modeling, and human radiation dose calculation. This method dynamically calculates the radiation dose of workers wearing nuclear radiation protective clothing during nuclear facility decommissioning.

[0005] Chinese patent publication number CN7330187B discloses a method for simulating radiation dose distribution in nuclear facility decommissioning. The method includes the following steps: Step 1: Determine the geometric information of the radiation field to be simulated in the nuclear decommissioning facility scenario, including the location of the radiation source and the geometric information of the shielding object; Step 2: Establish a dose monitoring point distribution network based on the location of the radiation source and the location of the shielding object to extract sample data; Step 3: Divide the dose distribution calculation into partitioned dose calculation and non-partitioned dose calculation based on whether there is a shielding object in the radiation field; Step 4: Construct a radial basis function neural network model based on the sample data; Step 5: Calculate the dose value at any point using the inverse distance weighted method; Step 6: Calculate the radiation field dose distribution. This method achieves the goal of simplifying the radiation field dose distribution calculation by relying on a small number of dose monitoring points without requiring a radiation source model. Furthermore, the method achieves radiation field dose distribution calculation that is sensitive to shielding effects.

[0006] However, the dose estimation technology of the existing technology is not flexible and lacks the ability to deal with the impact of position changes of facilities and equipment during the decommissioning of nuclear facilities. However, during the decommissioning of nuclear facilities, some radiation sources originally located in the nuclear facilities will inevitably be exposed. That is, the radiation field will continue to change as the operation progresses, and this change will often increase the exposure dose of the operators. Therefore, the existing technology is difficult to be truly effectively used for the needs of actual operations.

[0007] In addition, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the applicant studied a large number of documents and patents when making the present invention, but due to space limitations, not all details and contents are listed in detail. However, this does not mean that the present invention does not have the characteristics of these prior arts. On the contrary, the present invention already has all the characteristics of the prior art, and the applicant reserves the right to add relevant prior art to the background technology. Summary of the Invention

[0008] In response to the shortcomings of the existing technology, the present invention provides a method for assessing the human exposure dose during nuclear facility decommissioning. The method utilizes a dose assessment system, wherein the dose assessment system is used to assess the human exposure dose during the nuclear facility decommissioning operation based on the three-dimensional scene model and radiation field model it calls.

[0009] According to a preferred embodiment, the dose assessment method comprises the following steps:

[0010] Scan the current equipment's location information to obtain the coordinate data of the currently operated equipment and operators.

[0011] Based on the coordinate data of the equipment being operated, the three-dimensional scene model and radiation field model are called.

[0012] Obtain disassembly and assembly information of nuclear facilities during nuclear decommissioning operations to correct the three-dimensional scene model and radiation field model.

[0013] The real-time and cumulative doses received by workers are calculated based on the revised radiation field model.

[0014] According to a preferred embodiment, the method for correcting the three-dimensional scene model includes the following steps:

[0015] Introducing the mass attenuation coefficient and mass thickness of nuclear facilities,

[0016] Associate the mass thickness information with the 3D coordinate system of the 3D scene model,

[0017] Dividing at least part of the nuclear facility into voxels dν facilitates the modification of the 3D scene model at a small scale.

[0018] According to a preferred embodiment, the method for correcting the radiation field model includes the following steps:

[0019] The existence variable σ is introduced to describe whether the voxel dν exists between the human body and the radiation source.

[0020] Applying the existential variable σ to the volume element dν yields the integral expression for mass thickness:

[0021] The intensity of the emitted rays is calculated based on the attenuation law of the rays in the material and the existing radiation field model is corrected according to the intensity data.

[0022] According to a preferred embodiment, the above method is based on GPU-accelerated human dose assessment technology to realize real-time dose and cumulative dose calculation, so as to realize human organ-level dose calculation based on the human dose model.

[0023] According to a preferred embodiment, the above method comprises the following steps:

[0024] Establish the functional relationship between absorbed dose and time and space:

[0025] The radiation weight factors of different types of rays are introduced and the absorbed doses are summed to obtain the equivalent dose of the organ.

[0026] The organ weight factor is introduced and the dose equivalent of each organ is summed to obtain the total effective dose of the human body. The differential time dt is taken to obtain the total real-time dose of the human body.

[0027] The real-time dose is integrated in the time domain to obtain the cumulative dose of the human body.

[0028] According to a preferred embodiment, the method further comprises the following steps:

[0029] Based on the operator's initial movement speed, the position of each organ of the operator at time t within the time range dt is calculated, and the position coordinates are associated with the three-dimensional coordinate system of the radiation field model.

[0030] The real-time dose of each organ is calculated to facilitate monitoring of the real-time dose of a single organ and determine whether it is excessive, thereby preventing over-irradiation.

[0031] According to a preferred embodiment, the method includes constructing a radiation field model based on radiation distribution data, wherein the radiation distribution data is obtained by measurement, and the measurement method includes the following steps:

[0032] Based on the spatial points planned for measurement in the radiation environment, the radiation distribution of the spatial points is measured to obtain the initial radiation distribution data.

[0033] The global radiation distribution data is obtained by simulating and supplementing the data of the unmeasured part based on the initial radiation distribution data.

[0034] According to a preferred embodiment, the construction of the radiation field model includes the following steps:

[0035] Establish a three-dimensional space coordinate system, introduce radiation distribution data and associate it with the three-dimensional space coordinates,

[0036] Introducing the absorption dose rate of human tissue to various types of radiation, establishing the functional relationship between the absorption dose rate and the three-dimensional space coordinate system,

[0037] According to the radiation source data, the radiation field model at the current moment is modified.

[0038] The radiation field model is associated with the three-dimensional scene model and output to the user in an editable manner.

[0039] According to a preferred embodiment, the dose assessment method includes a path planning method for nuclear decommissioning operations, wherein the path planning method includes the following steps:

[0040] In the 3D scene model associated with the radiation field model, select the operation start and end points and waypoints and enter the operation time.

[0041] Based on the coordinates of the starting and ending points and the waypoints and the operation time, at least one operation path with the minimum cumulative dose to the operators is calculated and planned.

[0042] According to a preferred embodiment, the dose assessment method further includes a reminder method, which includes the following steps:

[0043] Input the real-time dose threshold and cumulative dose threshold that the human body can withstand into the dose assessment system.

[0044] Determine whether the real-time dose and cumulative dose exceed the set threshold, and when the threshold is exceeded, use sound and light methods different from the environment to remind operators to implement safety measures.

[0045] Beneficial technical effects of the present invention:

[0046] This invention utilizes a dosimeter system to effectively calculate the radiation dose received by workers during nuclear decommissioning operations by simulating a three-dimensional scene model and a corresponding radiation field model of a real-world operation scenario. The dosimeter system displays these models in a visual manner, allowing workers to easily monitor their radiation levels in real time. Specifically, a correction method for the three-dimensional scene model and the radiation field model is introduced to minimize changes to the radiation field caused by the disassembly and installation of nuclear facilities during the operation. Combined with the dosimeter system's real-time dose calculation, this ensures that decommissioning workers receive an acceptable level of radiation during the operation, achieving optimal radiation protection.

[0047] The present invention utilizes a dose assessment method based on a human body model, which can realize dose calculation at the level of human organs, so that the real-time dose and cumulative dose received by each organ can be viewed in real time during the operation process, so that the operator can clearly and intuitively judge whether the current radiation environment will cause damage to their organs. At the same time, the present invention can also set real-time dose and cumulative dose reminder functions to ensure that the operator always performs the operation within the dose range allowed by their body. Through the above settings, the psychological burden of the operator is also reduced, making it easier to maintain a good working state in dangerous scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a schematic diagram of a dose assessment method according to a preferred embodiment of the present invention;

[0049] Figure 2 is a schematic diagram of a correction method in a dose assessment method according to a preferred embodiment of the present invention;

[0050] Figure 3 It is a schematic diagram of a dosage curve of a preferred embodiment provided by the present invention.

[0051] Reference Signs List

[0052] 1: Radiation source; 2: Obstacle; 3: Human body; 11: Incident ray; 12: Outgoing ray; 21: Voxel dν. DETAILED DESCRIPTION

[0053] The following is a detailed description with reference to the accompanying drawings.

[0054] like Figure 1As shown, a method for assessing human exposure dose during decommissioning of a nuclear facility utilizes a dose assessment system.

[0055] According to a preferred embodiment, a 3D scene model of a nuclear facility decommissioning scenario is pre-created and stored within the dose assessment system. This 3D scene model includes a 3D virtual environment and models of related facilities and equipment. Users can perform basic operations on the loaded 3D scene model, such as rotation, sectioning, and measurement. Based on its own 3D engine, the dose assessment system is compatible with 3D scene models in various formats and performs lightweight processing on the 3D scene model to facilitate rapid rendering of the 3D scene model for user browsing, viewing, and operation.

[0056] According to a preferred embodiment, the dose assessment system also stores radiation distribution data and is capable of processing the radiation field data based on its own algorithm and associating it with the spatial coordinates of the three-dimensional scene model. Preferably, the radiation distribution data is pre-measured and stored in the dosimeter system 10, and it needs to cover at least radiation field data and radiation source data, so that the dosimeter system 10 can more completely construct a radiation field model based on the above two types of radiation distribution data. Preferably, the radiation distribution data needs to include coordinate information, so that when constructing the radiation field model, the coordinate information is associated with the spatial coordinates of the three-dimensional scene model, so that the radiation field model and the three-dimensional scene model are one-to-one corresponding. Preferably, the radiation distribution data includes MCNP5 radiation data and radiation hotspot data, etc. Further preferably, for MCNP5 radiation data, the dose assessment system under this embodiment supports data processing in multiple coordinate systems. Preferably, when calling the three-dimensional scene model of the nuclear facility decommissioning scenario, the dose assessment system can automatically retrieve the corresponding radiation distribution data and associate the radiation distribution data with the three-dimensional scene model.

[0057] According to a preferred embodiment, the radiation distribution data is associated with a three-dimensional scene model and the radiation distribution data is visualized to present a visualized radiation field. Preferably, the presentation mode of the radiation field can be set to a variety of modes, such as texture rendering mode, heat map mode, point cloud mode, particle cloud mode, etc. Preferably, the dose assessment system supports editing of the radiation field dose distribution, for example, assigning corresponding colors to different doses at different positions in space, so that the visualized radiation field can more significantly reflect the spatial distribution of the dose and the depth of the dose distribution. Preferably, the dose assessment system also supports sectioning of the radiation field model, so that the user can more clearly view the dose distribution at different heights and different angles.

[0058] Example 1

[0059] According to a preferred embodiment, the dose assessment system can visualize the invisible radiation field so that the user can directly observe the distribution state of the radiation field and can rotate, slice and other operations on the radiation field model so as to observe the dose intensity of the radiation field from different angles and different depths. Before starting the operation, the user can make a preliminary manual assessment of the safety factor of the working environment by observing the radiation field model, providing an effective judgment basis for planning a reasonable working path.

[0060] According to a preferred embodiment, the radiation distribution data in the radiation environment is pre-stored in the dose assessment system, so that when it is needed, the dose assessment system can directly call the existing radiation distribution data. Preferably, the radiation distribution data can be obtained in advance through measurement and entered into the dose assessment system. Optionally, the measurement of the radiation field can be carried out in the following way: spatial points for measurement are planned in advance in the radiation environment. Preferably, the spatial points for measurement can be divided in an equidistant manner. On the basis of the initial radiation distribution data obtained by a limited number of measurements, the data of the unmeasured part in the corresponding space are supplemented by simulation to obtain the global radiation distribution data. The technician uses a handheld detector to measure the energy intensity and the corresponding type of rays at each spatial point in the working environment, and records the corresponding information in a portable storage device; or an intelligent robot can be used to replace manual work, so that the risk of excessive radiation exposure due to manual work can be avoided in an environment where radiation measurement is not performed.

[0061] Preferably, the measurement of the radiation field also includes obtaining the distribution information of the radiation source 1, the main nuclides of the radiation source 1, and the nuclide activity. Preferably, the distribution information of the radiation source 1 can also be obtained through manual on-site measurement and manually entered into a portable storage device. The radiation source 1 can be 1 Ag, 58 Co、 60 The activity of a short-lived nuclide decreases due to decay (the decay change of the activity of a long-lived nuclide can be ignored in a short time); or the continuous operation of a nuclear facility generates radioactive substances and increases the existing environmental radiation.

[0062] Preferably, the radiation field data and the radiation source 1 data stored in the portable storage device are imported into the dose assessment system, and the dose assessment system performs visualization processing on the radiation field data and the radiation source 1 data. Preferably, the visualization processing process includes:

[0063] S11: Establishing a three-dimensional spatial coordinate system, introducing the radiation field data and the radiation source 1 data to construct a three-dimensional radiation field model. Preferably, the dose assessment system supports data processing in multiple coordinate systems, such as a three-dimensional Cartesian coordinate system and a spherical coordinate system. Further preferably, due to the divergent nature of the radiation field, a spherical coordinate system is used to construct the radiation field model to simplify and accelerate the data processing process.

[0064] S12: Preferably, the total absorbed dose rate of the human body 3 tissues for various types of radiation is introduced, that is, the sum of the energy of various types of radiation deposited per unit mass of tissue in the human body 3 and per unit time due to ionizing radiation. Preferably, the radiation field model is a function of the absorbed dose rate under three-dimensional coordinates. Specifically, by selecting a specific three-dimensional coordinate point (r, θ, φ), the absorbed dose rate corresponding to the three-dimensional coordinate point can be obtained. Preferably, the radiation field model expresses the relationship between the absorbed dose rate and the spherical coordinate system through the following functional relationship: D = ψ(r, θ, φ), where D represents the absorbed dose rate of the human body 3 tissue at a certain point in space. Therefore, in the radiation field model, the absorbed dose rate can be obtained by determining a coordinate point.

[0065] S13: Preferably, the dose assessment system can also correct the radiation field at the current moment according to the data of the radiation source 1. For example, considering the decay of the radiation source 1, the time difference from the initial measurement to the present moment is calculated according to the attenuation properties of different radiation sources 1, and the current activity of the radiation source 1 is calculated based on the time difference, and a pre-built radiation field model is imported to correct it.

[0066] S14: Preferably, the dose assessment system can load the radiation field model simultaneously with the loading of the three-dimensional scene model. Preferably, the dose assessment system can calculate the coordinates of the radiation field model and associate them with the spatial coordinates of the three-dimensional scene model. Further preferably, the dose assessment system can also convert the spherical coordinate system of the radiation field model into a three-dimensional rectangular coordinate system and associate it with the three-dimensional rectangular coordinate system of the three-dimensional scene model.

[0067] S15: Preferably, the associated radiation field model and the three-dimensional scene model can be output to the user through a screen. Preferably, the presentation mode of the radiation field model can be set to a variety of modes, such as texture rendering mode, heat map mode, point cloud mode, particle cloud mode, etc.

[0068] S16: Preferably, the user can edit the radiation field model, for example, assigning corresponding colors to different doses at different spatial locations, so that the radiation field model can more clearly reflect the spatial distribution of the dose and the depth of the dose distribution. Preferably, the user can also slice the radiation field model to more clearly view the dose distribution at different heights and angles.

[0069] Example 2

[0070] This embodiment is a supplementary explanation of Embodiment 1, and repeated contents will not be repeated here.

[0071] According to a preferred embodiment, when performing dose assessment, the dose assessment system can call a three-dimensional scene model and a radiation field model according to the operation path selected by the user.

[0072] According to a preferred embodiment, the user can perform path planning for the work scene to obtain the optimal work path during the work process, thereby reducing the effective radiation dose received by the human body 3. The planning of the optimal work path can be implemented by a dose assessment system. Preferably, after loading the three-dimensional scene model and the corresponding radiation field model, the dose assessment system can calculate the effective dose received by the user during the work process based on the user-specified work starting point, work end point, work path points, and the user's scheduled work time, and simulate at least one work path for the user to select. Among them, the path with the minimum cumulative value of the effective radiation dose received by the user is called the optimal work path.

[0073] According to a preferred embodiment, the path planning steps of the dose assessment system may be as follows:

[0074] S21: The user obtains the three-dimensional scene model of the operation scene and the corresponding radiation field model, thereby obtaining the radiation situation of the scene where the operation is about to be performed. Preferably, the user can make a preliminary judgment on the operation environment based on the radiation situation to obtain the starting and ending points and waypoints for planning the operation path. Preferably, the user identifies the operation start and end points and waypoints in the three-dimensional scene model. Further preferably, the operation start and end points and waypoints can be identified by directly selecting them through a touch-type display device or by inputting the corresponding coordinates. Preferably, in this embodiment, each optional waypoint in the three-dimensional scene model corresponds to at least one device to be repaired, maintained or shielded that is equipped with a radiation source 1, and the staff will work at the waypoint location.

[0075] S22: The user inputs a predetermined operation time into the dose assessment system. Preferably, the operation time includes a stay time at each waypoint.

[0076] S23: The dose assessment system obtains the coordinates of the start and end points and the waypoints identified by the user in the three-dimensional scene model. In response to the path planning request, the system begins to calculate the start and end points, the waypoints, and the corresponding operation time by combining the radiation field model and the three-dimensional scene model, and plans at least one candidate path. It should be noted that the generated candidate path can at least start from the edge of the radiation field model, pass through the interior of the radiation field model, and then end at the edge of the radiation field model, so that the operator can follow the planned optimal path to minimize the effective dose when in the radioactive scene.

[0077] Example 3

[0078] This embodiment is a supplementary explanation of Embodiment 2, and the repeated contents will not be repeated here.

[0079] According to a preferred embodiment, the dose assessment system can also call radiation field model data along the path selected by the user, wherein the radiation field model data includes at least radiation field distribution data and distribution data of radiation source 1. Preferably, the dose assessment system can simulate, in a three-dimensional scene model, the spatial range swept by each organ of the human body 3 as it moves along the path, while simultaneously obtaining the time each organ spends along the path per unit space and calculating the real-time dose received by each organ of the human body 3 based on the radiation dose rate in that unit space. The cumulative dose is obtained by integrating the real-time dose over time.

[0080] According to a preferred embodiment, a GPU-accelerated 3D human dose assessment technique calculates the real-time and cumulative dose of the human body. Preferably, GPU acceleration technologies such as CUDA are used to identify and store relevant organ voxels based on a 3D human dose model. Preferably, the technique uses a 3D scene model to calculate the voxel dose within the organ bounding box, i.e., the dose received by each organ, thereby achieving dose assessment calculations at the 3D organ level.

[0081] Preferably, the absorbed dose of a certain organ of the human body 3 under the action of a certain ray can be expressed as a function of time and space. The absorbed dose multiplied by the radiation weight factor of the corresponding ray can obtain the equivalent dose of the organ. The equivalent doses of all organs of the human body 3 are multiplied by the organ weight factor and summed to obtain the total real-time dose of the human body 3 (the dose evaluation time is the differential time dt):

[0082]

[0083]

[0084]

[0085] Among them, D T,Rrepresents the average absorbed dose of organ T of ray type R, Represents a functional relationship. R is the radiation weight factor (measures the strength of the radiation effect caused by different rays in the human body), H T It represents the equivalent dose to organ T. eff is the total effective dose of the human body 3 (the measurement time is the differential time dt, which represents the real-time dose), ω T Represents the organ weight factor. Based on the real-time dose, the cumulative dose of the human body 3 is obtained by integrating the time. Preferably, the selected integral upper limit moment is the current moment, and the cumulative dose can be expressed as a function of time:

[0086]

[0087] Where P represents the cumulative dose.

[0088] According to a preferred embodiment, the dose calculation includes static calculation when performing path planning and dynamic calculation when starting the operation, wherein the static calculation is the dose estimation when the dose assessment system performs optimal path planning; the dynamic calculation is the real-time positioning of the operator and the real-time calculation of the dose received by the operator based on the distance and time of his movement.

[0089] Preferably, the steps of dynamic calculation may be as follows:

[0090] S31: first perform zeroing processing before entering the radiation field, that is, take the starting point of the operation path as the initial point of calculation.

[0091] S32: The dose assessment system monitors the operator's movement trajectory. The monitoring can obtain the current device's location information by scanning the QR code on the on-site device through the positioning module 11, and further obtain the current operator's location.

[0092] S33: Obtain the worker's initial movement speed. Based on the movement speed, calculate the position of each organ at time t within the time range dt while the worker is moving. Associate the worker's position coordinates with the three-dimensional coordinates of the radiation field model to obtain the radiation dose rate of the worker's current environment. Preferably, the real-time dose of each organ in the human body 3 is calculated in combination with the organ weight factors of the human body 3. This facilitates real-time monitoring of the dose of each organ and prevents certain organs susceptible to radiation damage from receiving excessive radiation, resulting in highly hazardous conditions such as acute radiation sickness.

[0093] According to a preferred embodiment, Figure 3 As shown, the real-time dose and the accumulated dose are configured to be displayed on the screen as a curve with respect to time.

[0094] Example 4

[0095] This embodiment is a supplementary explanation of Embodiment 3, and the repeated contents will not be repeated here.

[0096] According to a preferred embodiment, during the decommissioning of a nuclear facility, operations such as cutting and dismantling related equipment and facilities are required. This operation changes the actual operational scenario. Furthermore, changes in the location of equipment and facilities can also cause changes in the existing radiation distribution. In other words, the radiation distribution is directly related to the shape and position of physical objects in the actual operational scenario, and changes in the physical shape and position directly determine the radiation distribution. Therefore, during the decommissioning of a nuclear facility, the dose calculation method in Example 3 needs to be modified to more closely approximate the radiation distribution during actual nuclear facility decommissioning operations.

[0097] According to a preferred embodiment, Figure 1 As shown, there is an obstacle 2 between the radiation source 1 and the workers. Preferably, the obstacle 2 can be a component of the nuclear facility. Under the action of the obstacle 2, at least a portion of the radiation generated by the decay of the radiation source 1 is blocked by the obstacle 2, so that at least part of the energy of the radiation is deposited in the obstacle 2 before penetrating the obstacle 2. Preferably, during the decommissioning of the nuclear facility, the existing radiation field model is established with the obstacle 2 intact. After the operation is completed and the obstacle 2 is removed, the radiation generated by the radiation source 1 will directly irradiate the workers without any obstructions to deposit the radiation energy (not considering the attenuation of the radiation in air). In this case, the existing radiation field model is no longer applicable to the current dose calculation. In other words, the fundamental principle of the radiation field model (radiation distribution data) is based on the invariance of the nuclear facility's shape and position. Therefore, considering that inaccurate dose calculations can pose potential unknown hazards to nuclear facility decommissioning workers, and that these hazards are uncontrollable, it is necessary to modify the radiation field model during the operation to ensure that the error in the dose calculation is within an acceptable range.

[0098] According to a preferred embodiment, the above correction process may include the following parts: correction of the three-dimensional scene model and correction of the radiation field model.

[0099] Preferably, the three-dimensional scene model is modified by introducing the attenuation coefficient of the three-dimensional nuclear facility into the original three-dimensional scene model. Preferably, the attenuation coefficient can be expressed by the mass attenuation coefficient, that is, the degree of absorption of radiation by the nuclear facility material per unit mass thickness, where the mass thickness represents the mass of the material per unit area.

[0100] Preferably, the correction of the radiation field model is realized based on the correction of the three-dimensional scene model, and an existence variable is introduced into the radiation field model. Preferably, the existence variable refers to a judgment on whether there is an obstacle 2 between the current radiation source 1 and the operator. Preferably, the variable has only two states: yes / no. Further preferably, as Figure 2 As shown, when the existence variable is assigned to the obstacle 2, the obstacle 2 is first subjected to voxel differentiation, that is, the existence variable is determined for each voxel dν21 in the obstacle 2.

[0101] According to a preferred embodiment, the modification of the three-dimensional scene model includes the following steps:

[0102] S41: Add material data to the original three-dimensional scene model, introduce the mass attenuation coefficients of different material types, and obtain the thickness of each part of the nuclear facility by measuring or querying the specifications and dimensions of the nuclear facility design. Preferably, the mass thickness of the material can be obtained based on the density of the material. Preferably, the density of the material can be obtained from an existing material density table. Preferably, the intensity of the outgoing ray 12 can be obtained by using the exponential decay rate with the mass attenuation coefficient and mass thickness as variables. Taking photons as an example, this process can be expressed as the equation:

[0103]

[0104] Where μm is the mass attenuation coefficient, λ m is the mass thickness, I is the intensity of the outgoing ray 12, and I0 is the intensity of the incident ray 11.

[0105] S42: Preferably, the mass thickness information of each part of the nuclear facility is associated with the three-dimensional coordinate system of the three-dimensional scene model, so that the three-dimensional scene model has the necessary information for ray attenuation calculation.

[0106] S43: Preferably, at least part of the nuclear facilities are voxelized. Preferably, part of the nuclear facilities that need to be demolished is divided into voxels dν21, so that the radiation field model can be corrected on a differential scale when the radiation field model is corrected, thereby reducing the error caused by dose calculation.

[0107] According to a preferred embodiment, the modification of the radiation field model includes the following steps:

[0108] S51: Introduce the existence variable of the volume element dν21, which is represented by σ. Preferably, the value of σ is configured to be 0 or 1, 0 indicates that the current volume element does not exist between the radiation source 1 and the human body 3, and 1 indicates that the current volume element exists between the radiation source 1 and the human body 3.

[0109] S52: Preferably, the unit of the voxel dν21 is configured to be the same as the mass thickness λm Same unit (g*cm 2 ) so that the unit transformation step can be omitted when integrating the volume element dν21, reducing the number of calculation steps and operation time.

[0110] S53: The existence variable σ acts on the volume element dν21, which can be expressed as σdν21. Then the mass thickness can be expressed as:

[0111]

[0112] Here, the integration domain represents the sum of the regions where mass exists per unit area.

[0113] S54: Preferably, the intensity of the outgoing ray 12 is calculated according to the exponential decay rate of the ray, and the influence of Compton scattering is neglected, and the energy of the outgoing ray 12 is equal to its incident energy.

[0114] S55: Based on the intensity data of the outgoing ray 12 obtained in step S54, the existing radiation field model is modified. Preferably, the modification process is associated with the original coordinate system to make the modification effective.

[0115] Example 5

[0116] This embodiment is a supplementary explanation of embodiment 4, and the repeated contents will not be repeated here.

[0117] According to a preferred embodiment, since both real-time high-dose irradiation and the cumulative dose of the superposition are harmful to the health of the human body 3 when they exceed a certain range, a reminder function can be set in the dose assessment system to ensure that the operator is always within an acceptable dose range. Preferably, the steps for implementing the reminder function are as follows:

[0118] S61: Inputting a threshold value into the dose assessment system, the threshold value including a real-time dose threshold value and a cumulative dose threshold value.

[0119] S62: During the operation, if the real-time dose exceeds the real-time dose threshold, the reminder function will quickly alert the operator. When the cumulative dose exceeds a certain percentage of the cumulative dose threshold, the operator will also be reminded. Preferably, this percentage is configured to be 50% to ensure that the operator has sufficient time to return to the original route. Preferably, this reminder function can be implemented by stimulating the three human senses through sound and light. Further preferably, the reminders for real-time dose exceeding and cumulative dose exceeding can be set to different types of sound and light, respectively, to facilitate the operator to distinguish.

[0120] Example 6

[0121] This embodiment is a supplementary explanation of Embodiment 5, and the repeated contents will not be repeated here.

[0122] According to a preferred embodiment, before performing dose assessment, it is necessary to obtain the coordinate data of the currently operated equipment and the operator in the real scene, so that the dosimeter system 10 can call the three-dimensional scene model and the corresponding radiation field model corresponding to the current scene according to the coordinate data. Therefore, preferably, the dose assessment method includes a positioning method, and preferably, the positioning method includes the following steps:

[0123] S71: Scan the current device's location information. Preferably, this information can be stored in a QR code to obtain the location information of the physical object in the current environment and resolve it into three-dimensional coordinate data. Preferably, the scanning element in the positioning module 11 can be a laser scanning device or an optical image capture device (camera).

[0124] S72: The initial three-dimensional coordinate data obtained by scanning the current device is transmitted to the dosimeter system, and the dosimeter system performs data conversion calculation on the initial three-dimensional coordinate data to obtain processed three-dimensional coordinate data. Preferably, the processed three-dimensional coordinate data can be directly used to build a three-dimensional scene model.

[0125] It should be noted that the above-mentioned specific embodiments are exemplary, and those skilled in the art can come up with various solutions inspired by the disclosure of the present invention, and these solutions also belong to the disclosure scope of the present invention and fall within the protection scope of the present invention. Those skilled in the art should understand that the present invention specification and its drawings are illustrative and do not constitute a limitation of the claims. The scope of protection of the present invention is defined by the claims and their equivalents. The present invention specification contains multiple inventive concepts, such as "preferably", "according to a preferred embodiment" or "optionally", all of which indicate that the corresponding paragraph discloses an independent concept, and the applicant reserves the right to file a divisional application based on each inventive concept. Throughout the text, the features guided by "preferably" are only an optional method and should not be understood as having to be set, so the applicant reserves the right to abandon or delete the relevant preferred features at any time.

Claims

1. A method for assessing human exposure dose during decommissioning of a nuclear facility, the method utilizing a dose assessment system. in, A dose assessment system for assessing the radiation dose to a human body (3) during decommissioning of a nuclear facility based on a three-dimensional scene model and a radiation field model called by the system, Characterized in that the method comprises: Scan the current equipment's location information to obtain the coordinate data of the currently operated equipment and operators. Based on the coordinate data of the equipment being operated, the three-dimensional scene model and radiation field model are called. Obtaining the disassembly and assembly information of nuclear facilities during the nuclear decommissioning operation to correct the three-dimensional scene model and radiation field model, The real-time and cumulative doses received by the workers are calculated based on the modified radiation field model. The method for correcting the three-dimensional scene model comprises the following steps: Introducing the mass attenuation coefficient and mass thickness of nuclear facilities, Associating the mass thickness information with the three-dimensional coordinate system of the three-dimensional scene model, At least part of the nuclear facility is divided into voxels dν (21) to facilitate the modification of the three-dimensional scene model at a small scale.

2. The dose assessment method according to claim 1, characterized in that: The method for correcting the radiation field model includes the following steps: The existence variable σ is introduced to describe whether the voxel dν (21) exists between the human body (3) and the radiation source (1), Applying the existing variable σ to the volume element dν (21) yields the integral expression for mass thickness: The integration domain represents the sum of the regions with mass per unit area. The intensity of the emitted ray (12) is calculated based on the attenuation law of the ray in the material, and the existing radiation field model is corrected according to the intensity data.

3. The dose assessment method according to claim 2, characterized in that: The method utilizes a human (3) dose assessment technology based on GPU acceleration to realize real-time dose and cumulative dose calculation, so as to realize human (3) organ-level dose calculation based on a human (3) dose model.

4. The dose assessment method according to claim 3, characterized in that: The method comprises the following steps: Establish the functional relationship between absorbed dose and time and space: The radiation weight factors of different types of rays are introduced and the absorbed doses are summed to obtain the equivalent dose of the organ. The organ weight factor is introduced and the dose equivalent of each organ is summed to obtain the total effective dose of the human body (3). The total real-time dose of the human body (3) is obtained by taking the differential time dt. The real-time dose is integrated in the time domain to obtain the cumulative dose of the human body (3).

5. The dose assessment method according to claim 4, characterized in that: The method further comprises the following steps: Based on the operator's initial movement speed, the position of each organ of the operator at time t within the time range dt is calculated, and the position coordinates are associated with the three-dimensional coordinate system of the radiation field model. The real-time dose of each organ is calculated to facilitate monitoring of the real-time dose of a single organ and determine whether it is excessive, thereby preventing over-irradiation.

6. The dose assessment method according to claim 1, wherein: The method includes constructing a radiation field model based on radiation distribution data, wherein the radiation distribution data is obtained by measurement, and the measurement method includes the following steps: Based on the spatial points planned for measurement in the radiation environment, the radiation distribution of the spatial points is measured to obtain initial radiation distribution data. The global radiation distribution data is obtained by simulating and supplementing the data of the unmeasured part based on the initial radiation distribution data.

7. The dose assessment method according to claim 6, characterized in that: The construction of the radiation field model includes the following steps: Establish a three-dimensional space coordinate system, introduce radiation distribution data and associate it with the three-dimensional space coordinates, Introducing the absorption dose rate of human (3) tissue to various types of radiation, establishing the functional relationship between the absorption dose rate and the three-dimensional space coordinate system, According to the radiation source data, the radiation field model at the current moment is modified. The radiation field model is associated with the three-dimensional scene model and output to the user in an editable manner.

8. The dose assessment method according to claim 1, wherein: The method utilizes a path planning method for nuclear decommissioning operations, wherein the path planning method includes the following steps: In the 3D scene model associated with the radiation field model, select the operation start and end points and waypoints and enter the operation time. Based on the coordinates of the starting and ending points and the waypoints and the operation time, at least one operation path with the minimum cumulative dose to the operators is calculated and planned.

9. The dose assessment method according to claim 1, characterized in that: The method further includes a reminder method, which includes the following steps: Input the real-time dose threshold and cumulative dose threshold that the human body (3) can withstand into the dose assessment system, Determine whether the real-time dose and cumulative dose exceed the set threshold, and when the threshold is exceeded, use sound and light methods different from the environment to remind operators to implement safety measures.

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