JP7651441B2 - Radioactivity evaluation device - Google Patents

Description

The present invention relates to a device for evaluating the radioactivity of waste generated from nuclear power plants.

At nuclear power plants and other facilities, large amounts of waste, including activated waste and waste contaminated by radioactivity, are generated during the replacement of equipment during operation or decommissioning, and during the dismantling of facilities. This waste is classified according to the level of radioactivity concentration, such as the degree of activation or radioactive contamination. Of this, waste with relatively high, relatively low, and extremely low concentrations of radioactivity, collectively known as low-level radioactive waste, are disposed of underground, using methods such as intermediate depth disposal, shallow underground pit disposal, and trench disposal, respectively. Furthermore, high-level radioactive waste, which has a higher radioactivity concentration than low-level waste, is disposed of in the ground.

On the other hand, there is some waste that may be exempted from radiation protection regulations because its level of radioactive contamination is sufficiently small compared to natural radiation levels and the risk to human health is negligible. These are called clearance items.

Waste whose radioactivity concentration is determined to be below the clearance level does not need to be treated as radioactive waste, but is treated as clearance material. For this reason, clearance material can be transported outside the nuclear power plant, and if it can be reused, it is reused as a resource, and if reuse is not reasonable, it can be disposed of in the same way as normal industrial waste. Whether or not waste is below the clearance level is determined by measuring the radiation of the waste to be measured and evaluating the radioactivity from the measurement results.

An example of a conventional method for measuring and evaluating the radioactivity of waste is described in Patent Document 1. The method described in Patent Document 1 virtually divides the inside of a container that holds radioactive waste into multiple meshes, sets a radiation source and waste density for each mesh, measures radiation using radiation detectors placed around the container, and evaluates the distribution of radioactivity concentration throughout the entire waste stored in the container from the measurement results.

JP 2019-32208 A

In the method described in Patent Document 1, for the sake of efficiency, a virtual mesh is set within the container to evaluate the distribution of radioactivity concentration within the container, and the radioactivity of the entire container is evaluated. In other words, the method described in Patent Document 1 evaluates the radioactivity of the entire container on a mesh-by-mesh basis, and does not determine the contamination distribution of each individual waste stored in the container.

In addition, in the method described in Patent Document 1, the radioactivity concentration distribution is evaluated on the assumption that the radiation source is located at the location where the measurement efficiency of the radiation detector is the lowest, so the evaluation is highly conservative and the radioactivity concentration is calculated to be excessively high, and there is a possibility that waste that can be treated as clearance material will be evaluated as having higher radioactivity than the clearance level. Such waste will be treated as radioactive waste even though it is actually clearance material. If waste that can be treated as clearance material is treated as radioactive waste, the clearance material will be treated as radioactive waste, and the cost of radioactive waste treatment will increase.

As such, conventional technology has a problem in accurately assessing the radioactivity of waste generated by nuclear power plants in a way that reflects the actual contamination distribution of the waste.

The object of the present invention is to provide a radioactivity evaluation device that can accurately evaluate the radioactivity of waste generated from nuclear power plants while reflecting the actual contamination distribution of the waste.

The radioactivity evaluation device according to the present invention includes a shape data acquisition device that acquires shape data of waste generated from a nuclear power plant, a contamination distribution data acquisition device that acquires contamination distribution data of the waste, a conversion factor analysis device that inputs the shape data and the contamination distribution data to perform a radiation analysis and obtains a conversion factor for the waste that converts radiation measurement values into radioactivity, a radiation measurement device that measures the radiation of the waste, and a radioactivity calculation device that calculates the radioactivity of the waste using the radiation data of the waste measured by the radiation measurement device and the conversion factor for the waste.

The present invention provides a radioactivity evaluation device that can accurately evaluate the radioactivity of waste generated from nuclear power plants, reflecting the actual contamination distribution of the waste.

1 is a diagram showing a configuration of a radioactivity evaluation device according to a first embodiment of the present invention. FIG. 2 is a diagram showing an example of a process flow for evaluating the radioactivity of waste using the radioactivity evaluation device in the first embodiment. FIG. 2 is a diagram illustrating an example of a configuration of a conversion factor analysis device in the first embodiment. FIG. 11 is a diagram showing a configuration of a shape data acquisition device in a second embodiment of the present invention. FIG. 11 is a diagram showing a radiation measuring device for acquiring contamination distribution data of disassembled objects in Example 3 of the present invention. FIG. 11 is a diagram showing the configuration of a radioactivity evaluation device according to a fourth embodiment of the present invention. FIG. 13 is a diagram showing the configuration of a radioactivity evaluation device according to a fifth embodiment of the present invention.

The radioactivity evaluation device according to the present invention can accurately evaluate the radioactivity of waste generated from a nuclear power plant, reflecting the actual contamination distribution of the waste. Such waste includes, for example, waste generated with the replacement of equipment during the operation of a nuclear power plant, and dismantled materials generated with the dismantling of the facility during decommissioning of the nuclear power plant.

The radioactivity evaluation device according to the present invention determines a conversion coefficient for converting radiation measurement values into radioactivity from waste contamination distribution data. The radioactivity evaluation device according to the present invention can determine this conversion coefficient for each individual waste and calculate the radioactivity for each individual waste. Therefore, the radioactivity evaluation device according to the present invention can accurately evaluate the radioactivity of waste in accordance with the actual situation, reflecting the actual contamination distribution of the waste.

The following describes a radioactivity evaluation device according to an embodiment of the present invention with reference to the drawings. In the following embodiment, an example will be described in which waste generated from a nuclear power plant is dismantled material generated during the dismantling of the facility. Note that in the drawings used in this specification, identical or corresponding components are given the same reference numerals, and repeated explanations of these components may be omitted.

The radioactivity evaluation device according to the first embodiment of the present invention is described below.

Figure 1 shows the configuration of the radioactivity evaluation device according to this embodiment.

The radioactivity evaluation device according to this embodiment includes a contamination distribution analysis device 11, a contamination distribution database 21, a dismantling plan analysis device 12, and a dismantled object CAD database 22.

The contamination distribution analysis device 11 is a device for estimating the contamination distribution status of a nuclear power plant before the plant is dismantled. The contamination distribution analysis device 11 outputs contamination distribution data as the analysis result.

The contamination distribution database 21 stores the contamination distribution data output by the contamination distribution analysis device 11.

The dismantling plan analysis device 12 is a device that analyzes and determines a dismantling plan, such as the dismantling method, the size of the dismantled objects, and the construction procedures, before the dismantling of a nuclear power plant. The dismantling plan analysis device 12 outputs CAD data of the dismantled objects (dismantled object CAD data) as part of the analysis results. The dismantled object CAD data includes data on the shape and material of the dismantled objects. The data on the shape of the dismantled objects also includes the dimensions of the dismantled objects. The dismantling plan analysis device 12 is also a shape data acquisition device that acquires data on the shape of the dismantled objects (shape data) from the dismantling plan.

The dismantled object CAD database 22 stores the dismantled object CAD data output by the dismantling plan analysis device 12.

The contamination distribution data is obtained corresponding to the dismantled object CAD data. In other words, the contamination distribution analysis device 11 can obtain the contamination distribution (distribution of radioactivity or radiation dose rate) for each dismantled object obtained by the dismantling plan analysis device 12. The contamination distribution analysis device 11 is a contamination distribution data acquisition device that obtains the contamination distribution data of the dismantled objects.

The radioactivity evaluation device according to this embodiment further includes a conversion factor analysis device 13 and a conversion factor database 23.

The conversion factor analysis device 13 is a device that uses contamination distribution data and dismantled object CAD data as input data, performs radiation analysis from radiation generation to detection, and calculates the conversion factor for the dismantled object based on the results of this radiation analysis. The conversion factor analysis device 13 calculates the conversion factor corresponding to the dismantled object CAD data (conversion factor for each dismantled object).

The conversion factor is a factor expressed as the counting rate (cps: counts per sec) at which radiation is incident on a radiation detector per unit radioactivity (Bq), and is a factor used to convert radiation measurement values into radioactivity. By preparing a conversion factor in advance, the radioactivity evaluation device can convert the counting rate, which is the result of radiation measurement, into radioactivity when it obtains the counting rate. This conversion factor differs depending on the shape and material of the object being measured. For this reason, the conversion factor analyzer 13 finds a conversion factor corresponding to the dismantled object CAD data, i.e., a conversion factor for each dismantled object found by the dismantling plan analyzer 12.

The conversion coefficient database 23 stores the conversion coefficients for the dismantled items calculated by the conversion coefficient analysis device 13.

The radioactivity evaluation device according to this embodiment further includes a radiation measurement device 101, a measurement data collection device 102, a measurement database 121, a radioactivity calculation device 103, a radioactivity evaluation result output device 104, and a link information database 26.

The radiation measuring device 101 is equipped with a radiation detector and measures radiation from the dismantled object 51 generated from the nuclear power plant. The radiation detector measures the count rate of radiation (mainly gamma rays) incident from the dismantled object 51.

The measurement data collection device 102 collects the radiation (counting rate) measured by the radiation measurement device 101.

The measurement database 121 stores the measurement data of the radiation measurement device 101 collected by the measurement data collection device 102.

The radiation calculation device 103 inputs radiation data of the dismantled object 51 measured by the radiation measurement device 101 (radiation measurement data of the dismantled object 51) and the dismantled object CAD data corresponding to this dismantled object 51, and calculates the radioactivity of the dismantled object 51 from the radiation measurement data. Specifically, the radiation calculation device 103 calculates the radioactivity of this dismantled object 51 using the radiation measurement data of the dismantled object 51 and a conversion coefficient for this dismantled object 51 (more precisely, the conversion coefficient of the dismantled object CAD data corresponding to this dismantled object 51). The radiation calculation device 103 can calculate the radioactivity for each individual dismantled object 51. These are referred to as "target dismantled objects 51".

The radiation evaluation result output device 104 outputs the radiation of the dismantled object 51 calculated by the radiation calculation device 103. The radiation evaluation result output device 104 can output data calculated by the radiation evaluation device, such as contamination distribution data obtained by the contamination distribution analysis device 11 and dismantled object CAD data obtained by the dismantling plan analysis device 12.

The link information database 26 stores link information (e.g., ID information) that associates the dismantled object 51 measured by the radiation measurement device 101 with the dismantled object CAD data corresponding to the dismantled object 51. This link information will be described later.

Figure 2 is a diagram showing an example of a process flow for evaluating the radioactivity of waste using the radioactivity evaluation device according to this embodiment. In Figure 2, the process flow is indicated by solid arrows, and the data flow is indicated by dashed arrows. The process flow shown in Figure 2 includes a decommissioning planning step (step 1100), a conversion factor analysis step (step 1200), a dismantling step (step 1300), a radiation measurement step (step 1400), and a radioactivity evaluation step (step 1500).

First, in step 1001, a contamination status survey is conducted before the nuclear power plant is dismantled, and the survey data is stored in the survey database 24.

Next, the decommissioning planning step 1100 is executed.

In step 1101, the contamination distribution analysis device 11 estimates the contamination distribution by performing a simulation based on the survey data of the contamination status survey, and stores the estimated contamination distribution data (contamination distribution data) in the contamination distribution database 21. Existing technology can be used for the simulation to estimate the contamination distribution. For example, the contamination distribution analysis device 11 estimates the contamination distribution by determining the contamination at the survey point from the survey data of the contamination status survey, and determining the contamination at points other than the survey point from the contamination at the survey point (for example, by interpolation). Alternatively, the contamination distribution analysis device 11 can estimate the contamination distribution by using the operating history of the nuclear power plant.

In step 1102, the dismantling plan analysis device 12 performs a simulation of a dismantling plan for the nuclear power facility based on the contamination distribution data, and generates dismantling plan data. In the dismantling plan simulation, the dismantling plan analysis device 12 considers the contamination distribution data, work efficiency, radiation exposure dose, etc., to develop a dismantling plan including a dismantling method, dismantling procedure, and transportation procedure for dismantled objects, and generates dismantling plan data. The dismantling plan analysis device 12 stores the generated dismantling plan data in the dismantling plan database 25.

In step 1103, the dismantling plan analysis device 12 generates a model of the dismantled object as CAD data using the generated dismantling plan data, and stores the generated CAD data (dismantled object CAD data) in the dismantled object CAD database 22. A unique identification number is assigned to each piece of dismantled object CAD data.

Next, the conversion factor analysis step of step 1200 is executed. The conversion factor analysis step is processed by the conversion factor analysis device 13. The conversion factor analysis device 13 calculates a conversion factor for each dismantled object, i.e., for each piece of dismantled object CAD data.

In step 1201, the conversion factor analysis device 13 converts the dismantled item CAD data of the dismantled item for which the conversion factor is to be calculated into input data (dismantled item analysis model) for the simulation performed by the conversion factor analysis device 13.

In step 1202, in parallel with the processing of step 1201, the conversion factor analysis device 13 extracts contamination distribution data for the dismantled object CAD data of the dismantled object for which a conversion factor is to be calculated (i.e., the dismantled object CAD data converted into the analysis model in step 1201) from the contamination distribution database 21. Then, the conversion factor analysis device 13 converts the extracted contamination distribution data into input data (radiation source model) for the simulation executed by the conversion factor analysis device 13.

The radiation source model is generated as a distribution of radioactivity (Bq). The radioactivity values in the radiation source model may be a distribution of absolute values of radioactivity in space, or a distribution of radioactivity expressed in relative values. When the distribution of radioactivity is expressed in relative values, the shape of the graph (distribution shape) when the distribution of radioactivity is represented graphically is determined, and the distribution values are relative values.

In step 1203, the conversion factor analysis device 13 executes a simulation using the dismantled object analysis model and the radiation source model, and analyzes the transport of radiation emitted from the radiation source model for the dismantled object analysis model to obtain the counting rate (cps). For the simulation, the conversion factor analysis device 13 uses, for example, a Monte Carlo simulation code that is often used for radiation transport calculations. In addition, the conversion factor analysis device 13 can also use a simple shielding calculation code if the calculation takes too long with the Monte Carlo simulation code.

In step 1204, the conversion factor analysis device 13 calculates the conversion factor ε from the counting rate (cps) obtained in the simulation in step 1203, and stores the calculated conversion factor ε in the conversion factor database 23. The conversion factor analysis device 13 can calculate the conversion factor ε using an existing method.

The conversion factor analysis device 13 calculates a conversion factor ε for each dismantled object (dismantled object CAD data) and stores the calculated conversion factor ε in the conversion factor database 23 in association with the dismantled object (dismantled object CAD data). As described above, when calculating the conversion factor, the conversion factor analysis device 13 can use the distribution of radioactivity expressed in relative values as a radiation source model (contamination distribution data).

Next, the dismantling step of step 1300 will be described. The dismantling step is executed after the decommissioning planning step (step 1100), and may be executed in parallel with, for example, the conversion factor analysis step (step 1200).

In step 1301, workers dismantle (e.g., cut, process, etc.) the nuclear power plant facility based on the dismantling plan data stored in the dismantling plan database 25. Dismantling in step 1301 generates dismantled object 51. Since this dismantled object 51 was generated based on the dismantling plan data, corresponding dismantled object CAD data exists.

In step 1302, the radiation measuring device 101 assigns an identifier to the dismantled object 51. The identifier assigned to the dismantled object 51 can be displayed, for example, as a two-dimensional barcode.

In step 1303, the radiation measuring device 101 generates link information that associates the identifier assigned to the dismantled object 51 with the dismantled object CAD data corresponding to this dismantled object 51. This link information is information that associates the dismantled object 51 identified by the identifier with the dismantled object CAD data corresponding to the dismantled object 51 having this identifier, and is, for example, ID information. Then, the radiation measuring device 101 stores this link information in the link information database 26. For example, if the identifier assigned to the dismantled object 51 is displayed as a two-dimensional barcode, the link information can be set by registering the identification number assigned to the dismantled object CAD data in this two-dimensional barcode. As described above, a unique identification number is assigned to the dismantled object CAD data.

Next, the radiation measurement step of step 1400 will be described. In the radiation measurement step, radiation measurement is performed on the dismantled objects 51 generated in the dismantling step (step 1300). The dismantled objects 51 are generated whenever the dismantling step (step 1300) is executed. For this reason, the radiation measurement step is executed whenever the dismantling step is started.

In the following, the dismantled object 51 for which radiation is to be measured (i.e., the dismantled object 51 for which radioactivity is to be evaluated) is referred to as the "target dismantled object 51."

In step 1401, workers transport the target dismantled item 51 to a radiation measurement facility.

In step 1402, the worker recognizes the identifier assigned to the target dismantled object 51 and identifies the target dismantled object 51 for which radiation measurement is to be performed.

In step 1403, the worker places the target dismantled object 51 in the radiation measuring device 101.

In step 1404, the radiation measuring device 101 performs radiation measurement on the target dismantled object 51. The radiation measurement data of the target dismantled object 51 measured by the radiation measuring device 101 is collected by the measurement data collecting device 102 and stored in the measurement database 121.

In step 1405, the radiation measuring device 101 uses the identifier assigned to the target dismantled object 51 to extract link information for the target dismantled object 51 from the link information database 26. The radiation measuring device 101 then associates the link information for the target dismantled object 51 with the radiation measurement data for the target dismantled object 51. Through the processing of step 1405, the radiation measurement data for the target dismantled object 51 is associated with the dismantled object CAD data corresponding to the target dismantled object 51.

Then, the radioactivity evaluation step of step 1500 is performed.

In step 1501, the radioactivity calculation device 103 uses the link information extracted in step 1405 to read the conversion coefficient ε for the dismantled object CAD data corresponding to the target dismantled object 51 from the conversion coefficient database 23.

In step 1502, the radioactivity calculation device 103 calculates the radioactivity of the target dismantled object 51 from the radiation measurement data of the target dismantled object 51 measured by the radiation measurement device 101 using the conversion coefficient ε read from the conversion coefficient database 23. The radioactivity calculation device 103 can calculate the radioactivity for the target dismantled object 51, i.e., for each individual dismantled object 51.

Figure 3 is a diagram showing an example of the configuration of the conversion factor analysis device 13. The conversion factor analysis device 13 includes an analysis model conversion input device 130, a radiation analysis device 140, and a conversion factor calculation device 145.

The analytical model conversion input device 130 includes a data conversion device 131 and a source model conversion device 132.

The data conversion device 131 inputs the CAD data (demolition object CAD data 72) of the dismantled object 51 for which the conversion coefficient is to be calculated, and converts the input dismantled object CAD data 72 into input data (demolition object analysis model 141) for the radiation analysis device 140. The data conversion device 131 has a function of converting data on the shape and material of the dismantled object 51 contained in the dismantled object CAD data 72 to match the input format for the radiation analysis device 140, and generating the dismantled object analysis model 141. The dismantled object analysis model 141 is input data for the simulation performed by the radiation analysis device 140 in step 1203 of FIG. 2.

The radiation source model conversion device 132 inputs contamination distribution data 71 for the dismantled object CAD data 72 of the dismantled object 51 for which a conversion coefficient is to be calculated, and converts the input contamination distribution data 71 into input data (radiation source model 142) for the radiation analysis device 140. The radiation source model conversion device 132 has a function of converting the radiation source intensity information and spatial distribution information contained in the contamination distribution data 71 to match the input format for the radiation analysis device 140, and generating the radiation source model 142. As already described, the radiation source distribution (radioactivity value) in the radiation source model 142 may be a distribution of absolute values of radioactivity in space, or a distribution of radioactivity expressed in relative values. The radiation source model 142 is input data for the simulation performed by the radiation analysis device 140 in step 1203 of FIG. 2.

As described above, the radiation analysis device 140 inputs the dismantled object analysis model 141 and the radiation source model 142. The radiation analysis device 140 also sets a radiation detector model 143. The radiation detector model 143 is an analysis model of the radiation detector provided in the radiation measurement device 101, and is created based on the specifications of this radiation detector.

The radiation analysis device 140 executes a simulation using the dismantled object analysis model 141, the radiation source model 142, and the radiation detector model 143, and analyzes the transport of radiation emitted from the radiation source model 142. Specifically, the relative position of the radiation detector model 143 with respect to the dismantled object analysis model 141 is given, and the radiation source model 142 is given to the dismantled object analysis model 141. The radiation analysis device 140 analyzes the transport of radiation 144 (e.g., gamma rays) emitted from the radiation source model 142, and determines the number of counts (counting rate) per unit time of radiation 144 incident on the radiation detector model 143.

The conversion factor calculation device 145 calculates a conversion factor ε from the counting rate (cps) determined by the radiation analysis device 140, and stores the calculated conversion factor ε in the conversion factor database 23. The conversion factor database 23 stores a conversion factor ε for each dismantled object 51 (dismantled object CAD data 72). The conversion factor calculation device 145 can calculate the conversion factor ε using an existing method.

The radioactivity evaluation device according to this embodiment has the configuration described above, and can accurately evaluate the radioactivity of dismantled objects (waste) generated from nuclear power plants for each individual dismantled object 51, reflecting the actual contamination distribution of the dismantled object. In this embodiment, the conversion factor analyzer 13 calculates the conversion factor ε using the contamination distribution data 71 and the dismantled object CAD data 72, so that the radioactivity of the dismantled object 51 can be efficiently and rationally evaluated in accordance with the actual condition of the dismantled object 51.

A radioactivity evaluation device according to a second embodiment of the present invention will be described with reference to FIG. 4. The following mainly describes the differences between the radioactivity evaluation device according to this embodiment and the radioactivity evaluation device according to the first embodiment. In the radioactivity evaluation device according to the first embodiment, data on the shape of the dismantled object 51 is obtained from the dismantled object CAD data 72 generated using the dismantling plan data. The dismantling plan data is generated by the dismantling plan analysis device 12 through a dismantling plan simulation.

The radioactivity evaluation device according to this embodiment acquires data on the shape of the dismantled object 51 (shape data) by measuring the dismantled object 51, not from the dismantling plan data. The radioactivity evaluation device according to this embodiment is equipped with a shape data acquisition device, and measures the dismantled object 51 to acquire the shape data of the dismantled object 51 before executing the conversion factor analysis step of step 1200 shown in FIG. 2.

Figure 4 is a diagram showing the configuration of the shape data acquisition device in this embodiment. The shape data acquisition device in this embodiment includes a shape measurement device 150, a control device 151, and a shape database 152, and acquires shape data of the dismantled object 51.

The shape measuring device 150 measures the shape of the dismantled object 51. The control device 151 controls the shape measuring device 150 and acquires shape data of the dismantled object 51 from the shape measuring device 150. The shape database 152 stores the shape data of the dismantled object 51 acquired by the control device 151.

The shape measurement device 150 acquires shape data of the dismantled object 51 by measuring the shape of the dismantled object 51. Any device can be used for the shape measurement device 150, and for example, a device that irradiates a laser onto multiple points on the dismantled object 51 and acquires shape data of the dismantled object 51 as point cloud data from the difference in arrival time of the reflected signal from each point, or a stereo camera that measures shape using parallax can be used. It is common for stereo cameras to also acquire shape data of the dismantled object 51 as point cloud data. In this embodiment, the shape data of the dismantled object 51 stored in the shape database 152 is represented as a point cloud.

The shape data acquisition device in this embodiment further includes a point cloud CAD data conversion device 153. The point cloud CAD data conversion device 153 inputs the shape data (point cloud data) of the dismantled object 51 stored in the shape database 152, and converts the input point cloud data into CAD data. The point cloud CAD data conversion device 153 then stores this CAD data in the dismantled object CAD database 22 as dismantled object CAD data 72. This dismantled object CAD data 72 can be handled in the same way as the dismantled object CAD data 72 in Example 1.

In this embodiment, the shape data of the dismantled object 51 is not obtained from the dismantling plan data, but is obtained by measuring the dismantled object 51 with the shape measuring device 150. Therefore, with the radioactivity evaluation device of this embodiment, even if the shape of the dismantled object 51 differs from the shape of the dismantled object 51 based on the judgment of an on-site worker during dismantling in the dismantling step of FIG. 2 (step 1301), for example, the conversion coefficient ε of the dismantled object 51 can be calculated and the radioactivity of the dismantled object 51 can be accurately evaluated.

In this embodiment, when the dismantled object 51 is dismantled, the shape of the dismantled object 51 can be measured by the shape measuring device 150 to obtain the dismantled object CAD data 72. Then, in the radiation measurement step (step 1400 in FIG. 2), before performing radiation measurement (step 1404) on the target dismantled object 51, the shape of the target dismantled object 51 can be measured by the shape measuring device 150 to obtain the dismantled object CAD data 72, and this dismantled object CAD data 72 can be compared and collated with the dismantled object CAD data 72 obtained during dismantling. By collating this data, it is possible to associate the radiation measurement data of the target dismantled object 51 with the dismantled object CAD data 72 corresponding to the target dismantled object 51 (step 1405).

The radioactivity evaluation device according to this embodiment has the configuration described above, and by directly measuring the shape of the dismantled object, it can accurately and rationally evaluate the radioactivity of the dismantled object in accordance with the actual state of the dismantled object, even if the shape of the dismantled object differs from that at the time of planning. Furthermore, even if the demolition plan analysis device 12 cannot be used, the radioactivity evaluation device according to this embodiment can evaluate the radioactivity of the dismantled object in the same way as the radioactivity evaluation device according to Example 1, by directly measuring the shape of the dismantled object to obtain shape data. Furthermore, by measuring the shape of the dismantled object at the time of dismantling and radiation measurement, it is possible to associate the dismantled object with the CAD data of the dismantled object, and the radioactivity of the target dismantled object can be evaluated without mistaking it for other dismantled objects.

A radioactivity evaluation device according to a third embodiment of the present invention will be described with reference to FIG. 5. In the following, the radioactivity evaluation device according to this embodiment will be described, focusing mainly on the differences from the radioactivity evaluation device according to the first embodiment. In the radioactivity evaluation device according to the first embodiment, the contamination distribution analysis device 11 estimates the contamination distribution data 71.

The radioactivity evaluation device according to this embodiment does not estimate the contamination distribution data 71 using the contamination distribution analysis device 11, but rather obtains the contamination distribution data 71 by measuring the dismantled object 51. The radioactivity evaluation device according to this embodiment is equipped with a radiation measuring device, and before executing the conversion factor analysis step of step 1200 shown in FIG. 2, measures the dismantled object 51 with the radiation measuring device to obtain the contamination distribution data 71 of the dismantled object 51.

Figure 5 is a diagram showing a radiation measuring instrument 161 that acquires contamination distribution data 71 of the dismantled object 51. The radiation measuring instrument 161 measures measurement points set on the surface of the dismantled object 51 while moving, for example, along the arrows in Figure 5. The radiation measuring instrument 161 is a contamination distribution data acquisition device that acquires contamination distribution data of the dismantled object 51, and can be configured, for example, using a survey meter that measures dose rate.

In the radioactivity evaluation device according to this embodiment, the radiation measuring device 161 generates contamination distribution data 71 from the measurement values at each measurement point of the dismantled object 51. The contamination distribution data 71 may be a distribution of absolute values of radioactivity in space, or a distribution of radioactivity expressed in relative values. This contamination distribution data 71 can be handled in the same way as the contamination distribution data 71 in Example 1.

The radioactivity evaluation device according to this embodiment has the configuration described above, and by directly measuring the contamination distribution of the dismantled objects, it is possible to accurately and rationally evaluate the radioactivity of the dismantled objects in accordance with the actual conditions of the dismantled objects, even when the contamination distribution analysis device 11 cannot estimate the contamination distribution or when the contamination distribution estimated by the contamination distribution analysis device 11 cannot be used.

A radioactivity evaluation device according to a fourth embodiment of the present invention will be described with reference to FIG. 6. In the following, the radioactivity evaluation device according to this embodiment will be described, focusing mainly on the differences from the radioactivity evaluation device according to the first embodiment. In the radioactivity evaluation device according to the first embodiment, the contamination distribution analysis device 11 estimates the contamination distribution data 71.

The radioactivity evaluation device according to this embodiment does not estimate the contamination distribution data 71 using the contamination distribution analysis device 11, but instead obtains it by utilizing monitoring information on the corrosive environment within the reactor system and the evaluation results based on that information.

Figure 6 is a diagram showing the configuration of a radioactivity evaluation device according to this embodiment. In the radioactivity evaluation device according to this embodiment, the contamination distribution data acquisition device that acquires contamination distribution data of the dismantled objects in the radioactivity evaluation device according to embodiment 1 includes a corrosion potential measurement device 201 and a corrosion potential evaluation device 202.

The corrosion potential measuring device 201 is a device that measures the corrosion potential within the reactor system of a nuclear power plant. A device for measuring the corrosion potential is installed at the corrosion potential measurement point within the reactor system. In this embodiment, this device can be used as the corrosion potential measuring device 201.

The corrosion potential evaluation device 202 is a device that determines the distribution of the corrosion potential within the reactor system based on the measurement results by the corrosion potential measurement device 201. The corrosion potential evaluation device 202 determines the corrosion potential at points other than the corrosion potential measurement points within the reactor system, for example, by interpolating the corrosion potential values at the corrosion potential measurement points. Since it is difficult to install the corrosion potential measurement devices 201 throughout the reactor system, the corrosion potential distribution within the reactor system is determined by analysis using the corrosion potential evaluation device 202 from the measurement results of the corrosion potential measurement device 201 at the corrosion potential measurement points. The corrosion potential evaluation device 202 determines the corrosion potential distribution within the reactor system using an existing method based on the corrosion potential at the corrosion potential measurement points and the corrosion potential at points other than the corrosion potential measurement points.

Corrosion potential is an indicator of the corrosive environment inside a nuclear reactor, and is correlated with the deposition rate of Co-60, a radioactive nuclide. Therefore, the distribution of Co-60 deposition can be estimated from the distribution of corrosion potential.

The corrosion potential evaluation device 202 can use existing methods to estimate the distribution of Co-60 deposition amounts from the distribution of corrosion potential, and obtain contamination distribution data 71 from the distribution of Co-60 deposition amounts.

The corrosion potential measuring device 201 stores the measured corrosion potential in the contamination distribution database 21. The corrosion potential evaluating device 202 stores calculated data such as contamination distribution data 71 in the contamination distribution database 21. This contamination distribution data 71 can be handled in the same way as the contamination distribution data 71 in Example 1.

The radioactivity evaluation device according to this embodiment has the configuration described above, and can accurately and rationally evaluate the radioactivity of dismantled objects in accordance with the actual conditions of the dismantled objects by utilizing monitoring information on the corrosive environment within the reactor system and evaluation results based on this information.

A radioactivity evaluation device according to Example 5 of the present invention will be described with reference to FIG. 7. Below, the radioactivity evaluation device according to this example will be described, focusing mainly on the differences from the radioactivity evaluation device according to Example 1.

The radioactivity evaluation device according to this embodiment can improve the accuracy of the obtained contamination distribution data 71 by accumulating past data and learning the relationship between the reactor operation data and the contamination distribution data 71.

Figure 7 is a diagram showing the configuration of a radioactivity evaluation device according to this embodiment. The radioactivity evaluation device according to this embodiment further includes a radioactivity evaluation record database 302, a reactor operation database 303, and a learning estimation device 301 in addition to the components of the radioactivity evaluation device according to embodiment 1.

The radioactivity evaluation record database 302 stores radioactivity evaluation record data. The radioactivity evaluation record data includes previously obtained data such as contamination distribution data 71, demolition plan data, shape data of the dismantled objects 51, radioactivity data calculated by the radioactivity calculation device 103 for each dismantled object 51, actual measurement data of radiation distribution, and actual measurement data of radioactive contamination distribution.

The reactor operation database 303 stores reactor operation data, which is operation data for the reactor of a nuclear power plant. The reactor operation data includes data on the reactor's past operating history, such as the operating history of the reactor and the timing of reactor equipment replacement.

The learning estimation device 301 is a device that inputs reactor operation data and radioactivity evaluation result data, which are past performance data, and learns the relationship between the reactor operation data and contamination distribution data 71 using techniques such as deep learning. The learning estimation device 301 holds the learned relationship between the reactor operation data and the contamination distribution data 71 as learning data. When evaluating the radioactivity of dismantled material 51 generated from a nuclear power plant, the learning estimation device 301 inputs the reactor operation data, contamination distribution data 71, and dismantled material CAD data 72 of the nuclear power plant, and can accurately determine the contamination distribution data 71 by using the learning data.

In other words, the learning estimation device 301 learns the relationship between the reactor operation data and the contamination distribution data 71 from the reactor operation data and contamination distribution data 71 obtained in the past, and can use this learning data to highly accurately determine the contamination distribution data 71 of the dismantled object 51 from the reactor operation data of the nuclear power plant for evaluating the radioactivity of the dismantled object 51. If the contamination distribution data 71 is highly accurate, the accuracy of the conversion coefficient ε determined by the conversion factor analysis device 13 can be improved, and the radioactivity of the dismantled object 51 can be evaluated even more accurately.

For example, if the operating history of a reactor that is the new target of decommissioning is similar to the operating history of a reactor that has been decommissioned in the past, it is likely that the contamination distribution data 71 will also show similar trends. For this reason, if the radiation distribution or contamination distribution of dismantled objects 51 in decommissioning measures that have been carried out in the past is actually measured and then learned in association with the operating history, the accuracy of the contamination distribution data 71 will be further improved, which will in turn lead to a further improvement in the accuracy of the conversion coefficient ε.

The radioactivity evaluation device of this embodiment can improve the accuracy of contamination distribution data and conversion coefficients by accumulating and learning from past experience in dealing with decommissioning measures for nuclear power plants, and can more accurately and rationally evaluate the radioactivity of dismantled materials in accordance with the actual conditions of the dismantled materials.

The present invention is not limited to the above-mentioned examples, and various modifications are possible. For example, the above-mentioned examples have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to an embodiment having all of the configurations described. It is also possible to replace a part of the configuration of one example with the configuration of another example. It is also possible to add the configuration of another example to the configuration of one example. It is also possible to delete a part of the configuration of each example, or to add or replace other configurations.

11... Contamination distribution analysis device, 12... Dismantling plan analysis device, 13... Conversion factor analysis device, 21... Contamination distribution database, 22... Dismantled object CAD database, 23... Conversion factor database, 24... Survey database, 25... Dismantling plan database, 26... Link information database, 51... Dismantled object, 71... Contamination distribution data, 72... Dismantled object CAD data, 101... Radiation measurement device, 102... Measurement data collection device, 103... Radioactivity calculation device, 104... Radioactivity evaluation result output device, 121... Measurement database, 130... Analysis model conversion input device, 131...data conversion device, 132...ray source model conversion device, 140...radiation analysis device, 141...dismantled object analysis model, 142...radiation source model, 143...radiation detector model, 144...radiation, 145...conversion coefficient calculation device, 150...shape measurement device, 151...control device, 152...shape database, 153...point cloud CAD data conversion device, 161...radiation measurement device, 201...corrosion potential measurement device, 202...corrosion potential evaluation device, 301...learning and estimation device, 302...radioactivity evaluation results database, 303...reactor operation database.

Claims (6)

A shape data acquisition device for acquiring shape data of waste generated from a nuclear power plant;
A contamination distribution data acquisition device for acquiring contamination distribution data of the waste;
a conversion factor analyzer that inputs the shape data and the contamination distribution data to perform a radiation analysis and obtains a conversion factor for converting radiation measurement values into radioactivity for the waste;
a radiation measuring device for measuring radiation of the waste;
a radioactivity calculation device that calculates the radioactivity of the waste using radiation data of the waste measured by the radiation measurement device and the conversion coefficient for the waste;
Equipped with
The contamination distribution data acquisition device includes a corrosion potential measurement device and a corrosion potential evaluation device,
the corrosion potential measuring device measures a corrosion potential inside the nuclear power plant,
The corrosion potential evaluation device acquires the contamination distribution data from the distribution of the corrosion potential.
A radioactivity evaluation device characterized by: the shape data acquisition device is a disassembly plan analysis device,
the dismantling plan analysis device performs a simulation of a dismantling plan of the nuclear power plant to generate CAD data including the shape data.
The radioactivity evaluation device according to claim 1 . The shape data acquisition device includes a shape measurement device for measuring the shape of the waste,
The shape measuring device measures a shape of the waste to obtain the shape data as point cloud data.
The radioactivity evaluation device according to claim 1 . the radiation measuring device generates link information that associates an identifier given to the waste with the CAD data corresponding to the waste having the identifier;
The radioactivity evaluation device according to claim 2 . a radioactivity evaluation record database for storing the contamination distribution data obtained in the past;
a reactor operation database for storing reactor operation data, which is operation data of a reactor at the nuclear power plant;
a learning and estimation device that inputs the reactor operation data stored in the reactor operation database and the contamination distribution data stored in the radioactivity evaluation record database, and learns a relationship between the reactor operation data and the contamination distribution data;
Equipped with
the learning and estimation device utilizes the learned relationship between the reactor operation data and the contamination distribution data to determine the contamination distribution data from the reactor operation data of the nuclear power plant for evaluating the radioactivity of the waste;
The radioactivity evaluation device according to claim 1 . the conversion factor analysis device uses data on the distribution of radioactivity expressed in relative values as the contamination distribution data when determining the conversion factor;
The radioactivity evaluation device according to claim 1 .

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