CN114201878A

CN114201878A - Nuclear facility retired human body irradiated dose evaluation method

Info

Publication number: CN114201878A
Application number: CN202111514314.XA
Authority: CN
Inventors: 周雄; 姜海涛; 唐世豪
Original assignee: Dms Corp
Current assignee: Dms Corp
Priority date: 2021-12-10
Filing date: 2021-12-10
Publication date: 2022-03-18

Abstract

The invention relates to a nuclear facility retired human body irradiated dose evaluation method, which utilizes a dose evaluation system, wherein the dose evaluation system is used for evaluating the irradiated dose of a human body in a nuclear facility retired operation process according to a three-dimensional scene model and a radiation field model called by the dose evaluation system. Characterized in that the dose assessment method comprises the following steps: scanning the position information of the current equipment to acquire the coordinate data of the current operated equipment and the operator; calling a three-dimensional scene model and a radiation field model based on coordinate data of the operated equipment; acquiring nuclear facility disassembly and assembly information in a nuclear decommissioning operation process to modify a three-dimensional scene model and a radiation field model; and calculating the real-time dose and the accumulated dose received by the operator based on the corrected radiation field model.

Description

Nuclear facility retired human body irradiated dose evaluation method

Technical Field

The invention relates to the technical field of radiation protection, in particular to a nuclear facility retired human body irradiated dose evaluation method.

Background

At present, the energy demand in the world is increasing, and clean energy is vigorously promoted in China, wherein nuclear energy is adopted by more and more countries as an energy supply mode with high efficiency and no pollution, and the construction of nuclear power in China becomes a national business card and a domestic nuclear power station is just before the rise.

The nuclear power station and related nuclear facilities contain radioactivity, have potential danger to human beings and the environment, carry out operation under the radiation environment, including the maintenance of equipment facilities, the disassembly process in nuclear facility decommissioning engineering and the like, firstly, the requirement that the personnel exposure dose is concerned in real time according to the safety and accessibility (operability) requirements of operation under the radiation environment needs to be considered, and due to the complexity of the radiation environment, different positions, the decay characteristic difference of different species of nuclides and the superposition of the spatial distribution of the nuclides, the exposure doses of different positions in a scene are greatly different, so the conditions of instant dose and accumulated dose borne by the equipment and the personnel in the radiation field are very complex.

Chinese patent publication No. CN11456A discloses a nuclear facility decommissioning human body irradiated dose evaluation method, and particularly relates to a simulation method for simplifying nuclear decommissioning workers into a stylized model and dynamically calculating human body irradiated dose based on a point-nuclear integration method. The invention comprises the following steps: adopting a stylized model to construct a virtual human model; converting the critical organization of the stylized model into a series of probe points; calculating equivalent dose of key tissue detection points by adopting a point kernel integration method; and calculating the effective dose of the virtual human when the decommissioning activity is terminated, and realizing the evaluation of the irradiated dose of the workers in the decommissioning process. The invention comprises three modules of decommissioning environment modeling, stylized human body model modeling and human body irradiated dose calculation, and realizes dynamic calculation of irradiated dose of workers wearing nuclear radiation protection clothing in the decommissioning process of nuclear facilities.

Chinese patent publication No. CN7330187B discloses a simulation method of nuclear facility retired radiation field dose distribution. The method comprises the following steps of 1: determining geometric information of a radiation field to be simulated in a nuclear retirement facility scene, the position of a radiation source and geometric information of a shielding object; step 2: according to the position of the radiation source and the position of the shielding object, establishing a dose monitoring point distribution network for extracting sample data; and step 3: dividing the dose distribution calculation into a partitioned dose calculation and a non-partitioned dose calculation according to whether a shielding object exists in a radiation field; and 4, step 4: constructing a radial basis function neural network model according to the sample data; and 5: calculating the dose value of any point by an inverse distance weight method; step 6: the dose distribution of the radiation field is calculated. The invention realizes that the radiation field dose distribution calculation is carried out by depending on a small number of dose monitoring points without a radioactive source item model, and the steps are simpler and more convenient; the invention realizes the calculation of the radiation field dose distribution which influences the shielding effect.

However, the dose estimation in the prior art has no variability, and lacks the handling of the influence of the position change of the facility equipment during the decommissioning operation of the nuclear facility, but inevitably some radiation sources originally located in the nuclear facility are exposed during the decommissioning operation of the nuclear facility, namely, the radiation field is continuously changed along with the development of the operation process, and the change is much to increase the irradiation dose of the operating personnel, so that the prior art is difficult to be really and effectively used for the requirement of the actual operation.

Furthermore, on the one hand, due to the differences in understanding to the person skilled in the art; on the other hand, since the applicant has studied a great deal of literature and patents when making the present invention, but the disclosure is not limited thereto and the details and contents thereof are not listed in detail, it is by no means the present invention has these prior art features, but the present invention has all the features of the prior art, and the applicant reserves the right to increase the related prior art in the background.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a nuclear facility retired human body irradiated dose evaluation method, which utilizes a dose evaluation system, wherein the dose evaluation system is used for evaluating the irradiated dose of a human body in the nuclear facility retired operation process according to a three-dimensional scene model and a radiation field model called by the dose evaluation system.

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

scanning the position information of the current device to acquire the coordinate data of the current operated device and the operator,

a three-dimensional scene model and a radiation field model are called based on coordinate data of the worked device,

acquiring the disassembly and assembly information of the nuclear facilities in the nuclear decommissioning operation process to correct the three-dimensional scene model and the radiation field model,

and calculating the real-time dose and the accumulated dose received by the operator based on the corrected radiation field model.

According to a preferred embodiment, the method of modifying a three-dimensional scene model comprises the following steps:

the mass attenuation coefficient and mass thickness of the incoming nuclear facilities,

the mass thickness information is associated with a three-dimensional coordinate system of the three-dimensional scene model,

at least part of the nuclear facilities are divided into volume elements d ν, so that the three-dimensional scene model can be corrected on a small scale conveniently.

According to a preferred embodiment, the method of modifying the radiation field model comprises the steps of:

a presence variable sigma is introduced for describing whether the voxel d v is present between the human body and the radiation source,

applying the presence variable σ to the voxel d ν and obtaining an integral expression of mass thickness:

the intensity of the emergent ray is calculated based on the attenuation rule of the ray in the substance, and the existing radiation field model is corrected according to the intensity data.

According to a preferred embodiment, the method is based on a human body dose evaluation technology accelerated by a GPU to realize calculation of real-time dose and accumulated dose so as to realize dose calculation at a human body organ level based on a human body dose model.

According to a preferred embodiment, the method comprises the following steps:

establishing the function relationship of absorbed dose with time and space:

introducing radiation weight factors of different types of rays and summing absorbed doses to obtain equivalent dose of the organ,

introducing organ weight factors, summing the dose equivalent of each organ to obtain the total effective dose of human body, taking differential time dt to obtain the total real-time dose of human body,

and integrating the real-time dose in a time domain to obtain the accumulated dose of the human body.

According to a preferred embodiment, the method further comprises the steps of:

calculating the positions of the organs in the dt time range of the operator based on the initial moving speed of the operator, and relating the position coordinates to a three-dimensional coordinate system of the radiation field model,

the real-time dose for each organ is calculated to facilitate monitoring of the real-time dose for individual organs and to determine whether there is excess, preventing excessive exposure.

According to a preferred embodiment, the method comprises constructing a radiation field model based on radiation distribution data, wherein the radiation distribution data is obtained by measurement, the measurement method comprising the steps of:

measuring the radiation distribution of the space point based on the space point position planned for measurement in the radiation environment to obtain initial radiation distribution data,

and simulating and complementing the data of the part which is not measured based on the initial radiation distribution data to obtain global radiation distribution data.

According to a preferred embodiment, the construction of the radiation field model comprises the following steps:

establishing a three-dimensional space coordinate system, introducing radiation distribution data and associating the radiation distribution data with the three-dimensional space coordinate system,

introducing the absorption dose rate of human tissues to various rays, establishing the functional relation between the absorption dose rate and a three-dimensional space coordinate system,

the radiation field model at the current moment is corrected according to the radiation source data,

the radiation field model is associated with the three-dimensional scene model and output to the user in a manner that can be edited.

According to a preferred embodiment, the dose assessment method comprises a path planning method for nuclear decommissioning, wherein the path planning method comprises the following steps:

selecting a work start point and a work stop point and an approach point in a three-dimensional scene model associated with the radiation field model and inputting a work time,

and calculating and planning at least one working path with the minimum accumulated dosage for the working personnel based on the coordinates of the starting point, the ending point, the path point and the working time.

According to a preferred embodiment, the dose assessment method further comprises a reminding method comprising the steps of:

inputting real-time dose threshold and accumulated dose threshold which can be born by human body into a dose evaluation system,

and judging whether the real-time dose and the accumulated dose exceed a set threshold value or not, and reminding the operator to execute safety measures by using a sound and light mode different from the environment when the real-time dose and the accumulated dose exceed the threshold value.

The invention has the beneficial technical effects that:

the invention utilizes the dosimeter system, implements effective calculation of the irradiated dose of the operating personnel in the nuclear decommissioning operation process by simulating the three-dimensional scene model and the corresponding radiation field model in the real operation scene, and the dosimeter system displays the models in a visual mode, so that the operating personnel can conveniently check the radiation level of the operating personnel in real time. The method is particularly introduced to a correction method of a three-dimensional scene model and a radiation field model, so that changes of the radiation field caused by the disassembly and assembly of nuclear facilities can be corrected as much as possible in the operation process, the real-time dose calculation of a binding agent measuring instrument system is realized, nuclear decommissioning operators can be ensured to be in the irradiation level acceptable by human bodies in the operation process, and the radiation protection optimization is realized.

The invention utilizes the dose evaluation method based on the human body model, can realize the dose calculation of the human body organ level, and can check the real-time dose and the accumulated dose of each organ in real time in the operation process, so that the operation personnel can clearly and intuitively judge whether the current radiation environment can cause damage to the organs. Meanwhile, the invention can also enable the operator to carry out operation within the dosage range allowed by the body of the operator all the time by setting the real-time dosage and the accumulated dosage reminding function. Through the arrangement, the psychological burden of operators is relieved, and a good operation state is kept in a dangerous scene conveniently.

Drawings

FIG. 1 is a schematic diagram of a dose assessment method according to a preferred embodiment of the present invention;

FIG. 2 is a schematic diagram of a correction method in a dose assessment method according to a preferred embodiment of the present invention;

FIG. 3 is a schematic illustration of a dose profile of a preferred embodiment of the present invention.

List of reference numerals

1: a radiation source; 2: an obstacle; 3: a human body; 11: incident rays; 12: emitting rays; 21: voxel d ν.

Detailed Description

The following detailed description is made with reference to the accompanying drawings.

As shown in fig. 1, a method for evaluating the exposure dose of a human body 3 in decommissioning of nuclear facilities utilizes a dose evaluation system.

According to a preferred embodiment, a three-dimensional scenario model relating to a nuclear facility decommissioning scenario is pre-established and stored in the dose assessment system, and includes a model of a three-dimensional virtual environment and associated facility equipment. The user can carry out basic operations such as rotating, sectioning and measuring on the loaded three-dimensional scene model. The dose evaluation system is based on a three-dimensional engine of the dose evaluation system, can be compatible with three-dimensional scene models in various formats, and carries out lightweight processing on the three-dimensional scene models so as to facilitate the system to quickly render the three-dimensional scene models which are convenient for a user to browse, view and operate.

According to a preferred embodiment, the dose evaluation system also has radiation distribution data stored therein and is able to process the radiation field data on the basis of its own algorithm and to correlate them 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, which at least needs to cover the radiation field data and the radiation source data, so that the dosimeter system 10 can more completely construct a radiation field model from the two types of radiation distribution data. Preferably, the radiation distribution data includes coordinate information, so that the coordinate information is associated with the spatial coordinates of the three-dimensional scene model when the radiation field model is constructed, so that the radiation field model and the three-dimensional scene model are in one-to-one correspondence. Preferably, the radiation distribution data includes MCNP5 radiation data, radiation hotspot data and the like, and further preferably, the dose evaluation system in the present embodiment supports data processing in multiple coordinate systems for MCNP5 radiation data. Preferably, upon invoking the three-dimensional scenario model of the nuclear facility decommissioning scenario, the dose assessment system is capable of automatically retrieving the corresponding radiation distribution data and associating the radiation distribution data with the three-dimensional scenario model.

According to a preferred embodiment, the radiation distribution data is associated with a three-dimensional scene model and is visualized to reveal a visualized radiation field. Preferably, the representation mode of the radiation field may be set to a plurality of modes, for example, a texture rendering mode, a thermal map mode, a point cloud mode, a particle cloud mode, and the like. Preferably, the dose assessment system supports editing of the dose distribution of the radiation field, for example, assigning respective colors for different doses at spatially different locations, respectively, 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 evaluation system also supports sectioning of the radiation field model, so that a user can more clearly view dose distribution conditions of different heights and different angle positions.

Example 1

According to a preferred embodiment, the dose evaluation system can perform visualization operation on an invisible radiation field so that a user can directly observe the distribution state of the radiation field, and can perform operations such as rotation and sectioning on the radiation field model so as to observe the dose intensity of the radiation field from different angles and different depths, before operation is started, the user can perform preliminary artificial evaluation on the safety coefficient of the operation environment by observing the radiation field model, and an effective judgment basis is provided for planning a reasonable operation path.

According to a preferred embodiment, the radiation distribution data in the radiation environment is pre-stored in the dose assessment system, so that the dose assessment system can directly recall the existing radiation distribution data when it is needed. Preferably, the radiation distribution data may be obtained in advance by measurement and entered into a dose evaluation system. Alternatively, the measurement of the radiation field can be performed by: space point locations for measurement are planned in a radiation environment in advance, preferably, the space point locations for measurement can be divided in an equidistant mode, and on the basis of initial radiation distribution data obtained by limited measurement, data of parts which are not measured in a corresponding space are completed through simulation to obtain global radiation distribution data. A technician holds a detector by hand to measure the energy intensity of each space point position in the working environment and the corresponding ray type, and records the corresponding information into the portable storage device; or the intelligent robot can replace manual operation, so that the risk of excessive radiation exposure caused by manual operation can be avoided in the environment without radiation measurement.

Preferably, the measurement of the radiation field further comprises acquiring information of the distribution of the radiation source 1, the predominant nuclear species of the radiation source 1 and the activity of the nuclear species. Preferably, the distribution information of the radiation source 1 is also available in the form of manual field measurements, entered manually into a portable storage device. The radiation source 1 may be composed of¹Ag、⁵⁸Co、⁶⁰Co, etc., which deposit over time and change the activity of the species, e.g., short lived species due to decaySo that the activity of the nuclide becomes small (the decay change of the activity of the long-lived nuclide is negligible in a short time); or radioactive materials and gains in existing environmental radiation due to the continued operation of the nuclear facility.

Preferably, the radiation field data and the radiation source 1 data stored in the portable storage device are imported into a dose evaluation system, and the dose evaluation system performs visualization processing on the radiation field data and the radiation source 1 data. Preferably, the visualization process comprises:

s11: establishing a three-dimensional space coordinate system, introducing radiation field data and constructing the radiation source 1 data into a three-dimensional radiation field model, and preferably, the dose evaluation system supports data processing under various coordinate systems, such as a three-dimensional Cartesian coordinate system and a spherical coordinate system. Further preferably, due to the divergent property of the radiation field, the radiation field model is constructed by adopting a spherical coordinate system, so that the data processing process is simpler, more convenient and faster.

S12: preferably, the total absorption dose rate of the human body 3 tissue to various types of rays is introduced, namely the sum of the energy deposited by the various types of rays in the human body 3 per unit mass tissue and per unit time due to ionizing radiation. Preferably, the radiation field model is a function of the absorption dose rate in three-dimensional coordinates, and specifically, a specific three-dimensional coordinate point (r, θ, Φ) is selected, that is, the absorption dose rate corresponding to the three-dimensional coordinate point can be obtained. Preferably, the radiation field model expresses the relation between the absorption dose rate and the spherical coordinate system by the following functional relation: d ═ ψ (r, θ, Φ), where D denotes the absorbed dose rate of human 3 tissue at some point in space. Therefore, in the radiation field model, determining a coordinate point can derive the absorption dose rate.

S13: preferably, the dose evaluation system is also able to correct the radiation field at the current time based on the radiation source 1 data, for example, in consideration of the decay of the radiation source 1, calculate the time difference from the initial measurement to the current time based on the decay properties of the different radiation sources 1 and calculate the current activity of the radiation source 1 based on the time difference, and introduce a pre-constructed radiation field model to correct it.

S14: preferably, the dose assessment system may load the radiation field model simultaneously with the loading of the three-dimensional scene model. Preferably, the dose assessment system is capable of calculating and correlating coordinates of the radiation field model with spatial coordinates of the three-dimensional scene model, and further preferably is further capable of converting and correlating a spherical coordinate system of the radiation field model to and with a three-dimensional rectangular coordinate system of the three-dimensional scene model.

S15: preferably, the radiation field model and the three-dimensional scene model after being correlated can be output to a user through a screen. Preferably, the representation mode of the radiation field model may be set to a plurality of modes, for example, a texture rendering mode, a thermal map mode, a point cloud mode, a particle cloud mode, and the like.

S16: preferably, the radiation field model can be edited by the user, for example, corresponding colors are respectively given to different doses at different spatial positions, so that the radiation field model can more significantly reflect the spatial distribution of the dose and the depth of the dose distribution. Preferably, the user can cut the radiation field model so as to more clearly view the dose distribution conditions of different heights and different angle positions.

Example 2

This embodiment is a supplementary description of embodiment 1, and repeated contents are not described again.

According to a preferred embodiment, the dose evaluation system can call up the three-dimensional scene model and the radiation field model according to the operation path selected by the user when carrying out dose evaluation.

According to a preferred embodiment, the user can plan the path of the operation scene to obtain the optimal working path during the operation process, thereby reducing the effective dose of the irradiation on the human body 3. The planning of the optimal working path can be realized by a dose evaluation system, preferably, after the three-dimensional scene model and the corresponding radiation field model are loaded, the dose evaluation system can calculate the effective dose of the user in the working process according to the working starting point, the working end point, the working passing point and the preset working time of the user, which are specified by the user, and simulate at least one working path for the user to select, wherein the path with the minimum total irradiation effective dose accumulated value of the user is called the optimal working path.

According to a preferred embodiment, the path planning step of the dose assessment system may be as follows:

s21: the user obtains a three-dimensional scene model of the operation scene and a corresponding radiation field model, so that the scene radiation condition of the operation to be performed is obtained. Preferably, the user can make a preliminary judgment on the working environment according to the radiation condition to obtain a start point, a stop point and a passing point for planning the working path. Preferably, the user identifies the operation start point and the operation stop point and the passing point in the three-dimensional scene model, and further preferably, the identification mode of the operation start point and the operation stop point and the passing point may be directly selected by a touch type display device, or corresponding coordinates may be input. Preferably, in this embodiment, each optional passing point in the three-dimensional scene model corresponds to at least one device to be overhauled, maintained, or shielded, which is loaded with the radiation source 1, and a worker operates at the position of the passing point.

S22: the user inputs a predetermined work time to the dose assessment system, preferably the work time comprises a dwell time at each approach point.

S23: the dose evaluation system acquires coordinates of a start point, a stop point and a passing point identified by a user in the three-dimensional scene model, responds to a path planning request, starts to combine the radiation field model and the three-dimensional scene model to calculate the start point, the stop point, the passing point and corresponding operation time and plans at least one path to be selected. It should be noted that: the generated path to be selected can at least start from the edge of the radiation field model, pass through the interior of the radiation field model and then end with the edge of the radiation field model, so that the operator can work according to the planned optimal path to receive the minimum effective dose when being in a radioactive scene.

Example 3

This embodiment is a supplementary description of embodiment 2, and repeated contents are not described again.

According to a preferred embodiment, the dose assessment system is further capable of retrieving radiation field model data on the path according to the path selected by the user, the radiation field model data comprising at least distribution data of the radiation field and distribution data of the radiation source 1. Preferably, the dose evaluation system can simulate the space range swept by each organ of the human body 3 moving along the human body 3 in the path in the three-dimensional scene model, obtain the stay time of each organ on the path of the unit space, calculate the real-time dose received by the organ of the human body 3 according to the radiation dose rate in the unit space, and obtain the accumulated dose by integrating the real-time dose with the time.

According to a preferred embodiment, the real-time dose as well as the cumulative dose of the human body 3 is calculated based on GPU-accelerated human body 3 dose assessment techniques. Preferably, GPU acceleration technology such as CUDA is adopted, and based on a human body 3 dose model, relevant organ voxels are identified and stored. Preferably, it invokes a three-dimensional scene model, calculating the voxel dose in the organ bounding box, i.e. the dose each organ receives, thus enabling dose assessment calculations at the human 3 organ level.

Preferably, the absorbed dose of an organ of the human body 3 under the action of a certain ray 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 weight factor of the corresponding ray, and the total real-time dose of the human body 3 can be obtained by multiplying the equivalent dose of all organs of the human body 3 by the organ weight factor and summing (the dose evaluation time is the differential time dt):

wherein D is_T,RRepresenting the average absorbed dose of an organ T of radiation type R,

representing the functional relationship. Omega_RIs a radiation weight factor (measuring the intensity of radiation effect caused by different rays in the human body 3), H_TThe equivalent dose of organ T is indicated. D_effFor the total effective dose (the time of measurement is differentiated by dt, which means the real-time dose) of the human subject 3, ω_TRepresenting organ weight factors. The accumulated dose of the body 3 is obtained on the basis of the real-time dose by integrating over time, preferably the selected integration upper limit moment is the current moment, then the accumulated dose can be expressed as a function of time:

wherein P represents the cumulative dose.

According to a preferred embodiment, the dose calculation comprises a static calculation when the path planning is performed and a dynamic calculation when the operation is started, wherein the static calculation is the dose estimation when the dose evaluation system performs the optimal path planning; the dynamic calculation is to position the operator in real time and calculate the dose the operator receives in real time according to the distance and time that the operator moves.

Preferably, the step of dynamically calculating may be as follows:

s31: the zero setting process is carried out before the radiation field is entered, namely the starting point of the operation path is taken as the initial point of calculation.

S32: the dose evaluation system monitors the operation moving track of the operator, and the monitoring can obtain the position information of the current equipment by scanning the two-dimensional code on the field equipment through the positioning module 11, so as to further obtain the position of the current operator.

S33: the method comprises the steps of obtaining the initial moving speed of an operator, calculating the position of each organ at the time t within the dt time range when the operator moves according to the moving speed, and associating the position coordinates of the operator to the three-dimensional coordinates of a radiation field model, so that the radiation dose rate of the current environment where the operator is located is obtained. Preferably, the real-time dose of each organ of the human body 3 is calculated by combining the organ weight factors of the human body 3, so that the real-time dose of each organ can be monitored in real time, and extremely harmful conditions such as acute radiation sickness and the like caused by excessive radiation irradiation on some organs which are easily damaged by radiation can be prevented.

According to a preferred embodiment, the real-time dose as well as the accumulated dose are configured as a curve over time displayed on a screen, as shown in fig. 3.

Example 4

This embodiment is a supplementary description of embodiment 3, and repeated contents are not described again.

According to a preferred embodiment, during the decommissioning of the nuclear facility, the relevant equipment needs to be cut, dismantled and the like, the operation changes the real operation scene, and the change of the position of the equipment also causes the change of the existing radiation distribution, in other words, the radiation distribution is directly related to the shape and the position of the object in the real operation scene, and the change of the shape and the position of the object directly determines the radiation distribution. Therefore, during the decommissioning process of the nuclear facility, the dose calculation method in embodiment 3 needs to be modified to more closely approach the radiation distribution of the real decommissioning operation of the nuclear facility.

According to a preferred embodiment, as shown in fig. 1, wherein there is an obstacle 2 between the radiation source 1 and the operating personnel, the obstacle 2 may preferably be an integral part of the nuclear installation, at least part of the radiation generated by the decay of the radiation source 1 is blocked by the obstacle 2 under the influence of 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, when the nuclear facility is decommissioned, the existing radiation field model is established under the condition that the obstacle 2 is not moved, and after the operation is completed, the obstacle 2 is removed, the radiation generated by the radiation source 1 can directly irradiate the operator without any shielding object to deposit the energy of the radiation (without considering the attenuation of the radiation in the air), in this case, the existing radiation field model cannot be applied to the current dose calculation, in other words, the basis (radiation distribution data) of the establishment of the radiation field model is based on the invariance of the shape and the position of the nuclear facility. Therefore, it is considered that the inaccuracy of the dose calculation brings possible unknown harm to the decommissioned workers of the nuclear facility, and the harm is uncontrollable, so that the radiation field model in the operation process needs to be corrected, and the error of the dose calculation is ensured to be within the allowable range.

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

Preferably, the three-dimensional scene model is modified by introducing an attenuation coefficient of the three-dimensional nuclear facility on the original three-dimensional scene model, and the attenuation coefficient can be expressed by adopting a mass attenuation coefficient, namely, the absorption degree of nuclear facility materials with unit mass thickness to the ray, wherein the mass thickness represents the mass of the substance with unit area.

Preferably, the modification of the radiation field model is based on a modification of a three-dimensional scene model, in which a presence variable is introduced, preferably a determination of whether an obstacle 2 is present between the current radiation source 1 and the operator, preferably only two states are present: yes/no. Further preferably, as shown in fig. 2, when the presence variable is given to the obstacle 2, the obstacle 2 is first subjected to voxel differentiation processing, that is, the presence variable is determined for each voxel d ν 21 in the obstacle 2.

According to a preferred embodiment, the modification of the three-dimensional scene model comprises the following steps:

s41: adding material data on the basis of an original three-dimensional scene model, introducing mass attenuation coefficients of different material types, and obtaining the thickness of each part of the nuclear facility by measuring or inquiring the specification and the size of the nuclear facility design. Preferably, the intensity of the outgoing ray 12 can be obtained by exponential decay rate with the mass decay coefficient and mass thickness as variables, which process can be expressed as the equation, taking photons as an example:

wherein μm is mass attenuation coefficient, λ_mFor mass thickness, I is the intensity of the emergent ray 12, I₀Is the intensity of the incident radiation 11.

S42: preferably, the mass thickness information of the respective site of the nuclear facility is associated to a three-dimensional coordinate system of the three-dimensional scene model, so that the three-dimensional scene model is provided with the necessary information for the ray attenuation calculation.

S43: preferably, at least part of the nuclear facilities are voxelized, and preferably, the part of the nuclear facilities which needs to be dismantled is divided into voxels d v 21, so that the radiation field model can be corrected on a differential scale when the radiation field model is corrected, and therefore errors brought by dose calculation are reduced.

According to a preferred embodiment, the modification of the radiation field model comprises the following steps:

s51: a presence variable of the voxel d ν 21 is introduced, which is denoted σ, preferably the value of σ is configured to be 0 or 1, 0 indicating that the voxel at present is not present between the radiation source 1 and the

body

3, 1 indicating that the voxel at present is present between the radiation source 1 and the body 3.

S52: preferably, the unit of the voxel d ν 21 is configured to correspond to the mass thickness λ_mSame units (g cm)²) So that the step of unit transformation can be omitted when the voxel d ν 21 is integrated, and the calculation steps and the calculation time are reduced.

S53: applying the presence variable σ to the voxel d ν 21, which can be expressed as σ d ν 21, the mass thickness can be expressed as:

where the integral domain represents the sum of the regions where mass is present per unit area.

S54: preferably, the intensity of the outgoing ray 12 is determined from the exponential decay rate of the ray, ignoring the effects of compton scattering, and the energy of the outgoing ray 12 is equal to its incident energy.

S55: the existing radiation field model is corrected based on the intensity data of the outgoing ray 12 obtained in the step S54. Preferably, the correction process is correlated to the original coordinate system, so that the correction is valid.

Example 5

This embodiment is a supplementary description of embodiment 4, and repeated contents are not described again.

According to a preferred embodiment, since the real-time high dose irradiation and the superimposed cumulative dose may be harmful to the health of the human body 3 when exceeding a certain range, a reminder function may be set in the dose evaluation system to ensure that the operator is always within an acceptable dose range. Preferably, the reminding function is implemented as follows:

s61: thresholds are entered in the dose assessment system, including real-time dose thresholds and cumulative dose thresholds.

S62: in the operation process, when the real-time dose exceeds the real-time dose threshold value, the reminding function quickly gives a reminder to the operator; the operator is also alerted when the accumulated dose exceeds a certain proportion of the accumulated dose threshold, preferably configured to 50% to ensure that the operator has sufficient time to return. Preferably, the reminding function can be realized by stimulating the sense of the human body 3 in an acousto-optic mode. Further preferably, the reminder for the real-time dose exceeding and the reminder for the accumulated dose exceeding may be set to different types of sounds and lights, respectively, for easy distinction by the operator.

Example 6

This embodiment is a supplementary description of embodiment 5, and repeated contents are not described again.

According to a preferred embodiment, before performing the dose evaluation, coordinate data of the currently operated device and the operator in the real scene need to be acquired, so that the dosimeter system 10 can call up a three-dimensional scene model corresponding to the current scene and a corresponding radiation field model according to the coordinate data, and therefore, preferably, the dose evaluation method includes a positioning method, and preferably, the positioning method includes the following steps:

s71: and scanning the position information of the current equipment, wherein the information can be preferably stored in a two-dimensional code, obtaining the position information of the real object in the current environment and analyzing the position information into three-dimensional coordinate data. Preferably, the element of the positioning module 11 used for scanning may be a laser scanning device, or an optical image capturing device (camera).

S72: and transmitting the initial three-dimensional coordinate data obtained by scanning the current equipment to a dosimeter system, and performing data conversion calculation on the initial three-dimensional coordinate data by the dosimeter system 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.

It should be noted that the above-mentioned embodiments are exemplary, and that those skilled in the art, having benefit of the present disclosure, may devise various arrangements that are within the scope of the present disclosure and that fall within the scope of the invention. It should be understood by those skilled in the art that the present specification and figures are illustrative only and are not limiting upon the claims. The scope of the invention is defined by the claims and their equivalents. The present description contains several inventive concepts, such as "preferably", "according to a preferred embodiment" or "optionally", each indicating that the respective paragraph discloses a separate concept, the applicant reserves the right to submit divisional applications according to each inventive concept. Throughout this document, the features referred to as "preferably" are only an optional feature and should not be understood as necessarily requiring that such applicant reserves the right to disclaim or delete the associated preferred feature at any time.

Claims

1. A nuclear facility retired human body irradiated dose evaluation method utilizes a dose evaluation system,

wherein, the dose evaluation system is used for evaluating the irradiated dose of the human body (3) in the decommissioning operation process of the nuclear facility according to the called three-dimensional scene model and the radiation field model,

characterized in that the method comprises:

2. Dose assessment method according to claim 1, characterized in that the method of modifying a three-dimensional scene model comprises the following steps:

associating the mass thickness information with a three-dimensional coordinate system of the three-dimensional scene model,

at least part of the nuclear facilities are divided into voxels d v (21), which facilitates the modification of the three-dimensional scene model on a small scale.

3. The dose assessment method of claim 2, wherein the method of modifying the radiation field model comprises the steps of:

introducing a presence variable σ for describing whether the voxel d ν (21) is present between the human body (3) and the radiation source (1),

applying said presence variable σ to the voxel d ν (21) and obtaining an integral expression of mass thickness:

the intensity of the outgoing radiation (12) is calculated on the basis of the attenuation law of the radiation in the substance and the existing radiation field model is corrected on the basis of the intensity data.

4. Dose assessment method according to claim 3, characterized in that it uses GPU acceleration based human (3) dose assessment techniques to enable real-time dose and cumulative dose calculation to enable human (3) organ level dose calculation based on human (3) dose models.

5. Dose assessment method according to claim 4, characterized in that it comprises the following steps:

establishing the function relationship of absorbed dose with time and space:

introducing organ weight factors, summing the dose equivalent of each organ to obtain the total effective dose of the human body (3), taking the differential time dt to obtain the total real-time dose of the human body (3),

the real-time dose is integrated in the time domain to obtain the accumulated dose of the human body (3).

6. The path planning method according to claim 5, characterized in that the method further comprises the steps of:

7. Dose assessment method according to claim 1, characterized in that the method comprises constructing a radiation field model based on radiation distribution data, wherein the radiation distribution data are acquired by measurements, the measurement method comprising the steps of:

measuring the radiation distribution of a space point position for measurement based on the space point position planned in a radiation environment to obtain initial radiation distribution data,

8. The dose assessment method of claim 7, wherein the construction of the radiation field model comprises the steps of:

introducing the absorption dose rate of the human body (3) tissue to various rays, establishing the functional relation between the absorption dose rate and a three-dimensional space coordinate system,

9. 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 comprises the steps of:

10. The dose assessment method of claim 1, further comprising a reminder method, said reminder method comprising the steps of:

inputting real-time dose threshold and accumulated dose threshold which can be born by a human body (3) into a dose evaluation system,