Method for constructing radiation field model of nuclear facility and dose evaluation system

Abstract

The invention relates to a nuclear facility radiation field model construction method and a dose evaluation system, and the system is configured to establish a three-dimensional space coordinate system, construct a three-dimensional radiation field model based on radiation field data and radiation source data, and correct the radiation field model at the current moment according to the radiation source data, introducing an attenuation coefficient of the three-dimensional nuclear facility on the original three-dimensional scene model to correct the three-dimensional scene model; correcting the radiation field model based on the corrected three-dimensional scene model; calling the three-dimensional scene model and the radiation field model according to an operation path selected by a user; and simulating the space range of each organ of the human body sweeping along with the movement of the human body in the working path in the three-dimensional scene model, obtaining the time of each organ staying on the path of the unit space, and calculating the real-time dose received by the human organ according to the radiation dose rate in the unit space. According to the invention, the change of the radiation field caused by the disassembly and assembly of the nuclear facility can be corrected, and the optimization of radiation protection is realized.

Description

[0001] The original basis for this divisional application is patent application number 202111514314.X, filed on December 10, 2021, entitled "A method for assessing human radiation dose during nuclear facility decommissioning". Technical Field

[0002] This invention relates to the field of radiation protection technology, and in particular to a method for constructing a radiation field model of a nuclear facility and a dose assessment system. Background Technology

[0004] Nuclear power plants and related nuclear facilities contain radioactivity, posing potential dangers to humans and the environment. When working in a radiation environment, including the maintenance of equipment and facilities and the dismantling process in nuclear facility decommissioning projects, the first consideration must be the safety and accessibility (operability) requirements for working in a radiation environment. Real-time monitoring of personnel radiation dose is also necessary. Due to the complexity of the radiation environment, the differences in 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 instantaneous and cumulative doses experienced by equipment and personnel in the radiation field are very complex.

[0005] Chinese patent CN11456A discloses a method for assessing human radiation dose during nuclear facility decommissioning. Specifically, it relates to a simulation method based on a point-kernel integration method, which simplifies decommissioning workers into a stylized model and dynamically calculates human radiation dose. The invention 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 of the key tissue detection points using the point-kernel integration method; and calculating the effective dose of the virtual human at the end of the decommissioning process, thus achieving radiation dose assessment for workers during decommissioning. The invention comprises three modules: decommissioning environment modeling, stylized human model modeling, and human radiation dose calculation, enabling dynamic calculation of radiation dose for workers wearing radiation protective clothing during nuclear facility decommissioning.

[0006] Chinese Patent Publication No. CN7330187A discloses a method for simulating the dose distribution of radiation fields during nuclear facility decommissioning. It 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 locations of the radiation source and 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 weighting method; Step 6: Calculate the dose distribution of the radiation field. This invention achieves radiation field dose distribution calculation without requiring a radiation source term model, relying on a small number of dose monitoring points, making the steps simpler; this invention also enables the calculation of radiation field dose distribution considering the influence of shielding effects.

[0007] However, existing dose estimation technologies are not adaptable and lack the ability to account for changes in the location of facilities and equipment during nuclear facility decommissioning operations. In the process of nuclear facility decommissioning, some radiation sources that were originally located within the nuclear facility will inevitably be exposed. That is, the radiation field will change continuously as the operation progresses, and this change will mostly increase the radiation dose to the workers. Therefore, existing technologies are difficult to use effectively for the needs of actual operations.

[0008] Furthermore, 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 this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a method for assessing human radiation dose during nuclear facility decommissioning. This method utilizes a dose assessment system, which is used to assess the radiation dose received by a human during nuclear facility decommissioning operations based on a three-dimensional scene model and a radiation field model it invokes.

[0010] According to a preferred embodiment, the dose assessment method includes the following steps:

[0011] Scan the current location information of the equipment to obtain the coordinate data of the currently operated equipment and personnel.

[0012] The three-dimensional scene model and radiation field model are invoked based on the coordinate data of the operating equipment.

[0013] To obtain information on the dismantling and assembly of nuclear facilities during nuclear decommissioning operations, the 3D scene model and radiation field model are corrected.

[0014] The real-time and cumulative doses received by workers were calculated based on the modified radiation field model.

[0015] According to a preferred embodiment, the method for correcting a 3D scene model includes the following steps:

[0016] Introducing the mass attenuation coefficient and mass thickness of nuclear facilities.

[0017] The mass thickness information is associated with the three-dimensional coordinate system of the three-dimensional scene model.

[0018] At least a portion of the nuclear facility is divided into voxels (dν), which facilitates the correction of the 3D scene model at a small scale.

[0019] According to a preferred embodiment, the method for modifying the radiation field model includes the following steps:

[0020] A presence variable σ is introduced to describe whether the volume element dν exists between the human body and the radiation source.

[0021] Applying the variable σ to the volume element dν, we obtain the integral expression for the mass thickness:

[0022] The intensity of the emitted rays is calculated based on the attenuation law of rays in matter, and the existing radiation field model is corrected based on the intensity data.

[0023] According to a preferred embodiment, the above method is based on GPU-accelerated human dose assessment technology to calculate real-time dose and cumulative dose, so as to realize human organ-level dose calculation based on human dose model.

[0024] According to a preferred embodiment, the above method includes the following steps:

[0025] Establish the functional relationship between absorbed dose and time and space:

[0026] By introducing radiation weighting factors for different types of radiation and summing the absorbed doses, the equivalent dose to the organ is obtained.

[0027] By introducing organ weighting factors and summing the equivalent doses of each organ, the total effective dose of the human body is obtained. Taking the differential time dt, the total real-time dose of the human body is obtained.

[0028] The cumulative dose to the human body is obtained by integrating the real-time dose over the time domain.

[0029] According to a preferred embodiment, the above method further includes the following steps:

[0030] Based on the worker's initial moving speed, the positions of each organ at time t within the time range dt are calculated, and these position coordinates are associated with the three-dimensional coordinate system of the radiation field model.

[0031] The real-time dose of each organ is calculated to facilitate monitoring of the real-time dose of individual organs and to determine whether there is an overdose, thus preventing excessive irradiation.

[0032] According to a preferred embodiment, the above method includes constructing a radiation field model based on radiation distribution data, wherein the radiation distribution data is obtained through measurement, and the measurement method includes the following steps:

[0033] Initial radiation distribution data is obtained by measuring the radiation distribution at spatial points planned in the radiation environment.

[0034] Global radiation distribution data is obtained by simulating and supplementing the data of the unmeasured parts based on the initial radiation distribution data.

[0035] According to a preferred embodiment, the construction of the radiation field model includes the following steps:

[0036] Establish a three-dimensional spatial coordinate system, introduce radiation distribution data and associate it with the three-dimensional spatial coordinate system.

[0037] By introducing the absorbed dose rate of human tissue to various types of radiation, a functional relationship between the absorbed dose rate and the three-dimensional spatial coordinate system is established.

[0038] The radiation field model at the current moment is corrected based on radiation source data.

[0039] Associate the radiation field model with the 3D scene model and output it to the user in an editable manner.

[0040] 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:

[0041] In the 3D scene model associated with the radiation field model, select the start and end points and path points of the operation, and enter the operation time.

[0042] Based on the coordinates of the start, end, and waypoints, as well as the operation time, at least one operation path with the minimum cumulative dose to the operator is calculated and planned.

[0043] According to a preferred embodiment, the dose assessment method further includes a reminder method, which includes the following steps:

[0044] Input the real-time dose threshold and cumulative dose threshold that the human body can tolerate into the dose assessment system.

[0045] It determines whether the real-time dose and cumulative dose exceed the set threshold, and when the threshold is exceeded, it alerts the operator to take safety measures using sound and light methods different from those in the environment.

[0046] Beneficial technical effects of the present invention:

[0047] The dose assessment system of this invention effectively calculates the radiation dose to workers during nuclear decommissioning operations by simulating a three-dimensional scene model and a corresponding radiation field model in a real-world work scenario. The system visualizes these models, allowing workers to monitor their radiation levels in real time. In particular, it introduces a method for correcting the three-dimensional scene model and radiation field model to minimize changes in the radiation field caused by the dismantling and installation of nuclear facilities during the operation. Combined with the real-time dose calculations of the dose assessment system, this ensures that nuclear decommissioning workers are at an acceptable level of radiation during the operation, achieving optimal radiation protection.

[0048] This invention utilizes a human body model-based dose assessment method to achieve dose calculation at the organ level. This allows for real-time monitoring of the real-time and cumulative doses received by each organ during operations, enabling workers to clearly and intuitively determine whether the current radiation environment will cause damage. Furthermore, this invention can be equipped with real-time and cumulative dose reminders to ensure that workers always operate within their body's permissible dose range. These features also reduce the psychological burden on workers, facilitating the maintenance of a good working state in hazardous environments. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of a preferred embodiment of the dose assessment method provided by the present invention;

[0050] Figure 2 This is a schematic diagram of a correction method in a preferred embodiment of the dose assessment method provided by the present invention;

[0051] Figure 3 This is a schematic diagram of a dose curve of a preferred embodiment provided by the present invention.

[0052] List of reference numerals

[0053] 1: Radiation source; 2: Obstacle; 3: Human body; 11: Incident ray; 12: Outgoing ray; 21: Volume element dν. Detailed Implementation

[0054] The following is a detailed explanation with reference to the accompanying drawings.

[0055] like Figure 1As shown, a method for assessing radiation dose to humans during the decommissioning of nuclear facilities is presented, which utilizes a dose assessment system.

[0056] According to a preferred embodiment, the dose assessment system pre-builds and stores a 3D scene model of a nuclear facility decommissioning scenario. This 3D scene model includes a 3D virtual environment and models of related facilities and equipment. Users can perform basic operations such as rotation, sectioning, and measurement on the loaded 3D scene model. Based on its own 3D engine, the dose assessment system is compatible with various formats of 3D scene models and performs lightweight processing on the 3D scene models to facilitate rapid rendering of 3D scene models that are easy for users to browse, view, and operate.

[0057] According to a preferred embodiment, the dose assessment system also stores radiation distribution data and can process the radiation field data based on its own algorithm and associate it with the spatial coordinates of the three-dimensional scene model. Preferably, the radiation distribution data is pre-measured and stored in the dose assessment system, and it needs to cover at least radiation field data and radiation source data, so that the dose assessment system can construct a relatively complete 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 correspond one-to-one. Preferably, the radiation distribution data includes MCNP5 radiation data and radiation hotspot data, etc. More preferably, for MCNP5 radiation data, the dose assessment system in 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.

[0058] According to a preferred embodiment, radiation distribution data is associated with a 3D scene model while simultaneously being visualized to display a visualized radiation field. Preferably, the radiation field's display mode can be set to multiple modes, such as texture rendering mode, heatmap 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 spatial locations, so that the visualized radiation field can more significantly reflect the spatial distribution and depth of the dose distribution. Preferably, the dose assessment system also supports sectioning of the radiation field model, allowing users to more clearly view the dose distribution at different heights and angles.

[0059] Example 1

[0060] According to a preferred embodiment, the dose assessment system can visualize invisible radiation fields so that users can directly observe the distribution of the radiation fields and can rotate and slice the radiation field model to observe the dose intensity of the radiation field from different angles and depths. Before starting work, users can make a preliminary human assessment of the safety factor of the working environment by observing the radiation field model, providing an effective basis for planning a reasonable work path.

[0061] According to a preferred embodiment, radiation distribution data in the radiation environment is pre-stored in the dose assessment system so that the system can directly access the existing radiation distribution data when needed. Preferably, the radiation distribution data can be obtained in advance through measurement and entered into the dose assessment system. Optionally, the radiation field measurement can be performed by pre-planning spatial points for measurement in the radiation environment. Preferably, the spatial points for measurement can be divided at equal intervals. Based on the initial radiation distribution data obtained from a limited number of measurements, the data of the unmeasured parts in the corresponding spaces is supplemented by simulation to obtain global radiation distribution data. Technicians use handheld detectors to measure the energy intensity and corresponding ray type of each spatial point in the work environment and record the corresponding information in a portable storage device; alternatively, intelligent robots can replace manual labor, avoiding the risk of excessive radiation exposure for manual labor in environments where radiation measurements are not performed.

[0062] Preferably, the measurement of the radiation field further includes acquiring the distribution information of radiation source 1, the main nuclides of radiation source 1, and the activity of the nuclides. Preferably, the distribution information of radiation source 1 can also be obtained through manual on-site measurement and manually entered into a portable storage device. Radiation source 1 can be... 1 Ag、 58 Co、 60 Composed of various nuclides such as Co, the activity of nuclides changes over time. For example, the activity of short-lived nuclides decreases due to decay (the decay change of activity of long-lived nuclides can be ignored in a short period of time); or the continuous operation of nuclear facilities generates radioactive materials and increases the existing amount of environmental radiation.

[0063] Preferably, the radiation field data and radiation source data stored in the portable storage device are imported into the dose assessment system, which then performs visualization processing on the radiation field data and radiation source data. Preferably, this visualization processing includes:

[0064] S11: Establish a three-dimensional spatial coordinate system, and construct a three-dimensional radiation field model by introducing radiation field data and radiation source data. 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. More preferably, due to the divergent nature of the radiation field, a spherical coordinate system is used to construct the radiation field model, making the data processing process simpler and faster.

[0065] S12: Preferably, the total absorbed dose rate of human tissue 3 to various types of radiation is introduced, that is, the total energy deposited per unit mass of tissue per unit time by various types of radiation due to ionizing radiation in human tissue 3. Preferably, the radiation field model is a function of the absorbed dose rate in three-dimensional coordinates. Specifically, by selecting a specific three-dimensional coordinate point (r, θ, φ), the absorbed dose rate corresponding to that three-dimensional coordinate point can be obtained. Preferably, the relationship between the absorbed dose rate and the spherical coordinate system is expressed by the following functional relationship: D = ψ(r, θ, φ), where D represents the absorbed dose rate of human tissue 3 at a certain point in space. Therefore, in this radiation field model, the absorbed dose rate can be obtained by determining a coordinate point.

[0066] S13: Preferably, the dose assessment system can also correct the radiation field at the current moment based on the radiation source data. For example, considering the decay of radiation source 1, the system calculates the time difference from the initial measurement to the present moment based on the decay properties of different radiation sources 1, calculates the current radiation source activity based on the time difference, and imports it into a pre-built radiation field model for correction.

[0067] S14: Preferably, the dose assessment system can load the radiation field model simultaneously with the 3D 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 3D scene model. More preferably, it can also convert the spherical coordinate system of the radiation field model into a 3D Cartesian coordinate system and associate it with the 3D Cartesian coordinate system of the 3D scene model.

[0068] S15: Preferably, the interconnected radiation field model and 3D scene model can be output to the user via the screen. Preferably, the presentation mode of the radiation field model can be set to multiple modes, such as texture rendering mode, heatmap mode, point cloud mode, particle cloud mode, etc.

[0069] S16: Preferably, the user can edit the radiation field model, for example, assigning corresponding colors to different doses at different locations in space, so that the radiation field model can more significantly reflect the spatial distribution and depth of the dose distribution. Preferably, the user can also segment the radiation field model to more clearly view the dose distribution at different heights and angles.

[0070] Example 2

[0071] This embodiment is a supplementary explanation of Embodiment 1, and repeated content will not be repeated.

[0072] According to a preferred embodiment, when performing dose assessment, the dose assessment system can call up a three-dimensional scene model and a radiation field model based on the user-selected work path.

[0073] According to a preferred embodiment, the user can perform path planning for the work scenario to obtain the optimal work path during the operation, thereby reducing the effective dose received by the human body 3. The planning of the optimal work path can be achieved 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 operation based on the user-specified start point, end point, and path points, as well as the user's predetermined operation time, and simulate at least one work path for the user to choose from. The path with the minimum cumulative effective dose received by the user is called the optimal work path.

[0074] According to a preferred embodiment, the path planning steps of the dose assessment system can be as follows:

[0075] S21: The user obtains a 3D scene model of the work scenario and a corresponding radiation field model, thereby obtaining the radiation conditions of the scenario where the work will be carried out. Preferably, the user can make a preliminary judgment on the work environment based on the radiation conditions to obtain the start and end points and waypoints for planning the work path. Preferably, the user marks the start and end points and waypoints in the 3D scene model. More preferably, the marking of the start and end points and waypoints can be done by directly selecting them through a touch-screen display device or by inputting the corresponding coordinates. Preferably, in this embodiment, each selectable waypoint in the 3D scene model corresponds to at least one device equipped with radiation source 1 that needs to be inspected, maintained, or shielded, and the worker will work at the waypoint location.

[0076] S22: The user inputs a predetermined operation time into the dose assessment system, preferably including the dwell time at each transit point.

[0077] S23: The dose assessment system acquires the coordinates of the start, end, and waypoints identified by the user in the 3D scene model. Responding to the path planning request, it begins to combine the radiation field model and the 3D scene model to calculate the start, end, and waypoints, as well as the corresponding work time, and plans at least one candidate path. It should be noted that the generated candidate path must start from the edge of the radiation field model, pass through the interior of the radiation field model, and end at the edge of the radiation field model, so that workers in a radioactive environment can follow the planned optimal path to receive the minimum effective dose.

[0078] Example 3

[0079] This embodiment is a supplementary explanation of embodiment 2, and repeated content will not be repeated.

[0080] According to a preferred embodiment, the dose assessment system can also retrieve radiation field model data along the path selected by the user. This radiation field model data includes at least the distribution data of the radiation field and the distribution data of radiation source 1. Preferably, the dose assessment system can simulate the spatial range swept by various organs of the human body 3 along the aforementioned path in a three-dimensional scene model. Simultaneously, it obtains the time each organ spends on the path within a unit space and calculates the real-time dose received by the human organ based on the radiation dose rate within that unit space. Integrating the real-time dose over time yields the cumulative dose.

[0081] According to a preferred embodiment, a GPU-accelerated human dose assessment technology calculates the real-time dose and cumulative dose of human body 3. Preferably, GPU acceleration technologies such as CUDA are used to identify and store relevant organ voxels based on a human dose model. Preferably, it calls a three-dimensional scene model to calculate the voxel dose within the organ bounding box, i.e., the dose received by each organ, thereby achieving human organ-level dose assessment calculation.

[0082] Preferably, the absorbed dose of a certain organ of human body 3 under the action of a certain type of radiation can be expressed as a function of time and space. The equivalent dose of the organ can be obtained by multiplying the absorbed dose by the radiation weighting factor of the corresponding radiation. The total real-time dose of human body 3 is obtained by multiplying the equivalent doses of all organs of human body 3 by the organ weighting factor and summing them (the dose evaluation time is the differential time dt).

[0083]

[0084] Among them, D T,R This represents the average absorbed dose of organ T for radiation type R. This represents a functional relationship. τ represents three-dimensional spatial coordinates, and t represents time. ω R H represents the radiation weighting factor (which measures the intensity of the radiation effect caused by different rays in the human body). T This indicates the equivalent dose of organ T. (D) eff ω represents the total effective dose to the human body (measured by the derivative time dt, which represents the real-time dose). T This represents the organ weighting factor. The cumulative dose for the human body is obtained by integrating over time based on the real-time dose.

[0085] Preferably, if the selected upper limit of integration is the current time, then 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 during path planning and dynamic calculation at the start of operation. The static calculation is the dose estimation when the dose assessment system performs optimal path planning; the dynamic calculation is the real-time location of the operator and the calculation of the dose received by the operator based on the distance and time of movement.

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

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

[0091] S32: The dose assessment system monitors the movement trajectory of the operator. This monitoring can obtain the current location information of the equipment by scanning the QR code on the field equipment through the positioning module 11, and further obtain the current location of the operator.

[0092] S33: Obtain the initial movement speed of the worker, calculate the position of each organ at time t within the time range dt during the worker's movement based on the movement speed, and associate the worker's position coordinates with the three-dimensional coordinates of the radiation field model to obtain the radiation dose rate of the current environment in which the worker is located. Preferably, the real-time dose of each organ of human body 3 is calculated by combining the organ weighting factors of human body 3, so as to facilitate real-time monitoring of the real-time dose of each organ and prevent certain organs susceptible to radiation damage from receiving excessive radiation exposure, which could lead to extremely harmful situations such as acute radiation sickness.

[0093] According to a preferred embodiment, such as Figure 3 As shown, the real-time dose and cumulative dose are configured to be displayed as curves over time on the screen.

[0094] Example 4

[0095] This embodiment is a supplementary explanation of embodiment 3, and repeated content will not be repeated.

[0096] According to a preferred embodiment, during the decommissioning of a nuclear facility, it is necessary to cut and dismantle related equipment and facilities. This operation alters the actual work scenario, and the change in the location of the equipment and facilities also causes changes in the existing radiation distribution. In other words, the radiation distribution is directly related to the shape and location of the objects in the actual work scenario; changes in the shape and location of the objects 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 the actual decommissioning operation.

[0097] According to a preferred embodiment, such as Figure 1 As shown, an obstacle 2 exists 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 rays generated by the decay of the radiation source 1 is blocked by the obstacle 2, causing at least a portion of the energy of these rays to be deposited in the obstacle 2 before penetrating it. Preferably, during the decommissioning of the nuclear facility, the existing radiation field model is based on the assumption that the obstacle 2 is not moved. After the operation is completed and the obstacle 2 is removed, the rays generated by the radiation source 1 will directly irradiate the workers without any obstruction to deposit the energy of the rays (ignoring the attenuation of rays in the 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 establishing the radiation field model (radiation distribution data) is based on the invariance of the shape and location of the nuclear facility. Therefore, considering that the inaccuracy of dose calculation may bring possible unknown hazards to the 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 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 correction of the three-dimensional scene model is to introduce the attenuation coefficient of the three-dimensional nuclear facility on the original three-dimensional scene model. Preferably, the attenuation coefficient can be represented by the mass attenuation coefficient, that is, the degree of absorption of radiation by nuclear facility material per unit mass thickness, where mass thickness represents the mass of matter per unit area.

[0100] Preferably, the correction of the radiation field model is based on the correction of the three-dimensional scene model. An existence variable is introduced into the radiation field model. Preferably, this existence variable refers to a determination of whether an obstacle 2 exists between the current radiation source 1 and the worker. Preferably, this variable has only two states: yes / no. More preferably, such as... Figure 2As shown, when assigning existence variables to obstacle 2, obstacle 2 is first subjected to volume element differentiation, that is, the existence variables determine each volume element dν21 in obstacle 2.

[0101] According to a preferred embodiment, the correction of the 3D scene model includes the following steps:

[0102] S41: Add material data to the existing 3D 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 of the nuclear facility design. Preferably, the mass thickness of the material can be obtained based on the material density, which can be obtained from an existing material density table. Preferably, the intensity of the emitted ray 12 can be obtained by using the mass attenuation coefficient and mass thickness as variables through an exponential attenuation rate. Taking photons as an example, this process can be expressed as an equation:

[0103]

[0104] Where, μ m λ is the mass attenuation coefficient. m I represents the mass thickness, I represents the intensity of the outgoing ray 12, and I0 represents 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 facility is voxelized. More preferably, the part of the nuclear facility that needs to be dismantled is divided into voxels dν21 so that the radiation field model can be corrected at the differential scale when the radiation field model is corrected, thereby reducing the error caused by dose calculation.

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

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

[0109] S52: Preferably, the unit of volume element dν21 is configured to correspond to the mass thickness λ. m Same unit (g*cm) 2 This allows the unit transformation step to be omitted when integrating the volume element dν21, reducing the number of calculation steps and the computation time.

[0110] S53: If the variable σ is applied to the volume element dν21, it can be expressed as σdν21, then the mass thickness can be expressed as:

[0111]

[0112] Here, the integration domain represents the total mass of the regions within a unit area. v0 represents the initial voxel region, and v represents the final voxel region.

[0113] S54: Preferably, the intensity of the emitted ray 12 is determined based on the exponential decay rate of the ray, and the effect of Compton scattering is ignored. The energy of the emitted ray 12 is equal to its incident energy.

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

[0115] Example 5

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

[0117] According to a preferred embodiment, since real-time high-dose irradiation and cumulative doses exceeding a certain range can both harm human health, 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: Input a threshold in the dose assessment system, which includes a real-time dose threshold and a cumulative dose threshold.

[0119] S62: During operation, when the real-time dose exceeds the real-time dose threshold, the alert function quickly notifies the operator; when the cumulative dose exceeds a certain percentage of the cumulative dose threshold, the operator is also alerted. Preferably, this percentage is configured to 50% to ensure the operator has sufficient time to return via the original route. Preferably, this alert function can be implemented by stimulating the three senses through sound and light. More preferably, the alerts for exceeding the real-time dose and the alerts for exceeding the cumulative dose can be set to different types of sounds and lights to facilitate differentiation by the operator.

[0120] Example 6

[0121] This embodiment is a supplementary explanation of embodiment 5, and repeated content will not be repeated.

[0122] According to a preferred embodiment, before performing dose assessment, it is necessary to obtain the coordinate data of the currently operated equipment and personnel in the real scene, so that the dose assessment system can call the three-dimensional scene model and the corresponding radiation field model corresponding to the current scene based on 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 physical objects in the current environment and parse it into three-dimensional coordinate data. Preferably, the element used for scanning 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 from scanning the current device is transmitted to the dose assessment system. The dose assessment system performs data transformation calculations 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 specific embodiments described above are exemplary. Those skilled in the art can devise various solutions inspired by the disclosure of this invention, and these solutions all fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification and its accompanying drawings are illustrative and do not constitute a limitation on the claims. The scope of protection of this invention is defined by the claims and their equivalents. This specification contains multiple inventive concepts; terms such as "preferredly," "according to a preferred embodiment," or "optionally" indicate that the corresponding paragraph discloses an independent concept. The applicant reserves the right to file divisional applications based on each inventive concept. Throughout the text, features introduced by "preferredly" are merely optional and should not be construed as mandatory. Therefore, the applicant reserves the right to abandon or delete relevant preferred features at any time.

Claims

1. A dose assessment system for a nuclear facility, characterized in that, The system is configured as follows: Establish a three-dimensional spatial coordinate system and construct a three-dimensional radiation field model based on radiation field data and radiation source data; The radiation field model at the current moment is corrected based on radiation source data; Specifically, the attenuation coefficient of the three-dimensional nuclear facility is introduced into the original three-dimensional scene model to correct the three-dimensional scene model; the radiation field model is then corrected based on the corrected three-dimensional scene model. The 3D scene model and radiation field model are invoked based on the user-selected work path; In the three-dimensional scene model, the spatial range swept by each organ of the human body (3) as it moves along the working path is simulated. At the same time, the time each organ stays on the path in the unit space is obtained, and the real-time dose received by the human body organ is calculated based on the radiation dose rate in the unit space.

2. The dose assessment system according to claim 1, characterized in that, The method for correcting the 3D scene model includes the following steps: Introducing the mass attenuation coefficient and mass thickness of nuclear facilities. The mass thickness information is associated with the three-dimensional coordinate system of the three-dimensional scene model. At least a portion of the nuclear facility is divided into voxels dν (21) to facilitate the modification of the three-dimensional scene model at a small scale.

3. The dose assessment system according to claim 1 or 2, characterized in that, The steps for modifying the radiation field model include: A presence variable σ is introduced to describe whether the volume element dν(21) exists between the human body (3) and the radiation source (1). Applying the existence variable σ to the volume element dν(21) yields the integral expression for the mass thickness: Wherein, the integration domain represents the total mass of the regions existing per unit area, v0 represents the initial volumetric region, and v represents the final volumetric region; λ m Indicates mass thickness; The intensity of the emitted ray (12) is calculated based on the attenuation law of rays in matter, and the existing radiation field model is corrected based on the intensity data.

4. The dose assessment system according to any one of claims 1 to 3, characterized in that, The steps for constructing the three-dimensional radiation field model include: Establish the functional relationship between absorbed dose and time and space: Among them, D T,R This represents the average absorbed dose of organ T for radiation type R. Indicates a functional relationship; τ represents three-dimensional spatial coordinates, and t represents time; By introducing radiation weighting factors for different types of radiation and summing the absorbed doses, the equivalent dose to the organ is obtained. By introducing organ weighting factors and summing the equivalent doses of each organ, the total effective dose of the human body (3) is obtained. The differential time dt is then used to obtain the total real-time dose of the human body (3). The cumulative dose of the human body (3) is obtained by integrating the real-time dose over the time domain.

5. The dose assessment system according to any one of claims 1 to 4, characterized in that, The system is also configured to: Based on the worker's initial moving speed, the positions of each organ at time t within the time range dt are 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 individual organs and to determine whether there is an overdose, thus preventing excessive irradiation.

6. The dose assessment system according to any one of claims 1 to 5, characterized in that, The system is also configured to: In the 3D scene model associated with the radiation field model, select the start and end points and path points of the operation, and enter the operation time. Based on the coordinates of the start, end, and waypoints, as well as the operation time, at least one operation path with the minimum cumulative dose to the operator is calculated and planned.

7. A method for constructing a radiation field model of a nuclear facility, characterized in that, The method includes: A three-dimensional spatial coordinate system is established, and a three-dimensional radiation field model is constructed based on radiation field data and radiation source data. The radiation field model at the current moment is corrected based on radiation source data. Specifically, a decay coefficient for the three-dimensional kernel facility is introduced into the original three-dimensional scene model to correct the three-dimensional scene model. The radiation field model is corrected based on the corrected 3D scene model.

8. The method according to claim 7, characterized in that, The steps for correcting the 3D scene model include: Introducing the mass attenuation coefficient and mass thickness of nuclear facilities. The mass thickness information is associated with the three-dimensional coordinate system of the three-dimensional scene model. At least a portion of the nuclear facility is divided into voxels dν (21) to facilitate the modification of the three-dimensional scene model at a small scale.

9. The method according to claim 7 or 8, characterized in that, The steps for modifying the radiation field model include: A presence variable σ is introduced to describe whether the volume element dν(21) exists between the human body (3) and the radiation source (1). Applying the existence variable σ to the volume element dν(21) yields the integral expression for the mass thickness: Wherein, the integration domain represents the total mass of the regions within a unit area, v0 represents the initial volumetric region, v represents the final volumetric region, and λ m Indicates mass thickness; The intensity of the emitted ray (12) is calculated based on the attenuation law of rays in matter, and the existing radiation field model is corrected based on the intensity data.

10. The method according to any one of claims 7 to 9, characterized in that, The method further includes: Based on the worker's initial moving speed, the positions of each organ at time t within the time range dt are 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 individual organs and to determine whether there is an overdose, thus preventing excessive irradiation.

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