Radioactive waste amount evaluation system and amount evaluation method

Abstract

To evaluate an amount of waste for every disposal classification in correspondence with a variation of input information.SOLUTION: A radioactive waste amount evaluation system has: radioactivity concentration attenuation calculation means that calculates radioactivity concentration of demolition waste by using a demolition waste inventory and a radioactivity attenuation period as input information; pre-demolition and post-decontamination radioactivity concentration calculation means that calculates radioactivity concentration by using a decontamination factor of pre-demolition decontamination as input information; demolition waste disposal classification determination means that determines a disposal classification of the demolition waste before demolition and after decontamination by using disposal classification concentration of the demolition waste as input information; post-demolition and post-decontamination radioactivity concentration calculation means that calculates the radioactivity concentration of the demolition waste by using a decontamination range and a decontamination factor of post-demolition decontamination as input information; post-demolition and post-decontamination demolition waste disposal classification determination means that determines the disposal classification of the demolition waste by using the disposal classification concentration of the demolition waste as input information; waste number calculation means that calculates the number of pieces of waste by using specifications of a waste container as input information; and amount evaluation means that evaluates an amount of waste for every disposal classification. The details of the input information are changed and set.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a radioactive waste quantity evaluation system and a radioactive waste quantity evaluation method. [Background technology]

[0002] In formulating a decommissioning plan for a nuclear facility such as a nuclear power plant, it is necessary to classify the waste generated by dismantling into disposal methods according to its radioactivity concentration, and to evaluate the amount of waste generated for each disposal category and the number of pieces that will be generated if it is put into a form that can be disposed of (waste packages).Low-level radioactive waste from dismantling is expected to be buried in the following categories, in descending order of radioactivity concentration: intermediate depth disposal (L1), pit disposal (L2), and trench disposal (L3).

[0003] In assessing the quantity of waste, there are various factors that affect the quantity of waste for each disposal category, such as the decay of radioactivity over time, the removal of radioactivity by decontamination before and after dismantling, the upper limit of radioactivity concentration that can be accepted into the repository, and the specifications of the waste container. Among these factors, the upper limit of radioactivity concentration that can be accepted into the repository and the specifications of the waste container will change depending on future repository designs, and some cannot be set at this stage. In order to formulate decommissioning plans for nuclear facilities under these circumstances, it is important to be able to trial the assessment of the quantity of waste for each disposal category under various conditions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-230223 [Patent Document 2] JP 2015-87300 A [Non-patent literature]

[0005] [Patent Document 1] Decommissioning Technical Report, No. 12 (pages 2-10) Summary of the Invention [Problem to be solved by the invention]

[0006] As an evaluation for formulating a decommissioning plan for a nuclear facility, there is a method of calculating the quantity of waste material (containers containing radioactive waste) by using three-dimensional information on radioactive waste to change the cutting points of the radioactive waste or by varying the combination of radioactive waste to be stored in a planned container, thereby improving the storage condition in the container (for example, Patent Documents 1 and 2).

[0007] In addition, calculation codes have been proposed that evaluate the amount of radioactive waste generated, the radiation exposure dose of workers, the number of man-hours required for dismantling work, etc., based on the type of object to be dismantled, the work process (e.g., dismantling method for tanks, pumps, pipes, valves), the quantity of the object to be dismantled, the radioactivity concentration, and the standard dismantling labor hours (e.g., Non-Patent Document 1).

[0008] The above-mentioned Patent Documents 1 and 2 assume that radioactive waste will be stored in specific containers and evaluate the quantity of waste packages according to the storage conditions. This evaluation does not take into account the effects of changes in the quantity of waste packages for each disposal category due to decay of radioactivity over time or decontamination before and after dismantling.

[0009] Furthermore, although Non-Patent Document 1 evaluates the amount of radioactive waste generated based on the quantity and radioactivity concentration of materials to be dismantled, it does not evaluate the change in the amount of radioactive waste generated for each disposal category that will occur as the standards for the radioactivity concentration accepted by disposal sites, which have not yet been determined, change.

[0010] The embodiments of the present invention have been made in consideration of the above-mentioned circumstances, and aim to provide a radioactive waste quantity evaluation system and a radioactive waste quantity evaluation method that can evaluate the quantity of waste bodies for each disposal category in response to at least one variation in the dismantling waste inventory, radioactive decay period, decontamination coefficient for pre-dismantling decontamination, disposal category concentration of dismantling waste, decontamination range and decontamination coefficient for post-dismantling decontamination, and waste body container specifications. [Means for solving the problem]

[0011] A radioactive waste quantity evaluation system according to an embodiment of the present invention is a radioactive waste quantity evaluation system that evaluates the quantity of radioactive waste for each disposal category in relation to the formulation of a plan for the treatment and disposal of radioactive waste generated in association with the decommissioning of a nuclear facility, and includes a radioactivity concentration decay calculation means that applies a radioactivity decay effect using a radioactivity decay period as input information based on a dismantling waste inventory containing the radioactive waste, which is input information, and calculates the radioactivity concentration of the dismantling waste; and a decontamination coefficient for pre-dismantling decontamination that is input information based on the radioactivity concentration calculated by the radioactivity concentration decay calculation means. a means for calculating a radioactivity concentration after pre-demolition decontamination that applies the decontamination effect of pre-demolition decontamination and calculates the radioactivity concentration of the demolition waste after pre-demolition decontamination; a demolition waste disposal category determination means that determines the disposal category of the demolition waste after pre-demolition decontamination based on the radioactivity concentration of the demolition waste after pre-demolition decontamination calculated by the radioactivity concentration after pre-demolition decontamination calculation means, using the disposal category concentration of the demolition waste as input information; and a means for determining the disposal category of the demolition waste after pre-demolition decontamination based on the radioactivity concentration of the demolition waste after pre-demolition decontamination calculated by the demolition waste disposal category determination means, using the decontamination range and decontamination coefficient of post-demolition decontamination as input information for the demolition waste after pre-demolition decontamination for each disposal category determined by the demolition waste disposal category determination means. and a post-demolition decontamination waste disposal classification determination means for determining a disposal classification for the demolition waste after decontamination based on the radioactivity concentration of the demolition waste after decontamination calculated by the post-demolition decontamination radioactivity concentration calculation means, using the disposal classification concentration of the demolition waste as input information; and a post-demolition decontamination demolition waste disposal classification determination means for determining a disposal classification for the demolition waste after decontamination based on the radioactivity concentration of the demolition waste after decontamination calculated by the post-demolition decontamination radioactivity concentration calculation means, using the specifications of the waste container as input information, based on the determination result of the post-demolition decontamination demolition waste disposal classification determination means for determining a disposal classification for the demolition waste after decontamination based on the specifications of the waste container The system has a waste body number calculation means for calculating the number of waste bodies by allocating the waste bodies to waste body containers, and a quantity evaluation means for aggregating the waste bodies for each disposal category based on the number of waste bodies calculated by the waste body number calculation means and evaluating the quantity of the waste bodies for each disposal category, and is characterized in that it is configured so that at least one piece of information content from the dismantling waste inventory, the radioactive decay period, the decontamination coefficient for pre-dismantling decontamination, the disposal category concentration of the dismantling waste, the decontamination range and decontamination coefficient for post-dismantling decontamination, and the specifications of the waste body container can be changed and set.

[0012] A method for evaluating the quantity of radioactive waste in an embodiment of the present invention is a method for evaluating the quantity of radioactive waste for each disposal category in relation to the formulation of a plan for the treatment and disposal of radioactive waste generated in association with the decommissioning of a nuclear facility, and includes the steps of: applying a radioactivity decay effect using a radioactivity decay period as input information based on a dismantling waste inventory including the radioactive waste, which is input information to a radioactivity concentration decay calculation means; and calculating the radioactivity concentration of the dismantling waste by a pre-dismantling post-decontamination radioactivity concentration calculation means based on the radioactivity concentration calculated by the radioactivity concentration decay calculation means. and a step of calculating the radioactivity concentration of the demolition waste after pre-demolition decontamination by applying the decontamination effect by pre-demolition decontamination using a decontamination coefficient of pre-demolition decontamination as input information; a step of a demolition waste disposal category determination means determining a disposal category for the demolition waste after pre-demolition decontamination based on the radioactivity concentration of the demolition waste after pre-demolition decontamination calculated by the pre-demolition decontamination radioactivity concentration calculation means using the disposal category concentration of the demolition waste as input information; and a step of a post-demolition decontamination radioactivity concentration calculation means determining the radioactivity concentration of the demolition waste after pre-demolition decontamination for each disposal category determined by the demolition waste disposal category determination means. A step of applying the decontamination effect of post-demolition decontamination to waste using the decontamination range and decontamination coefficient of post-demolition decontamination as input information and calculating the radioactivity concentration of the demolition waste after post-demolition decontamination, a step of a post-demolition demolition waste disposal category determination means determining the disposal category of the demolition waste after post-demolition decontamination based on the radioactivity concentration of the demolition waste after post-demolition decontamination calculated by the post-demolition decontamination radioactivity concentration calculation means using the disposal category concentration of the demolition waste as input information, and a step of a waste body number calculation means determining the disposal category of the demolition waste after post-demolition decontamination based on the determination result of the post-demolition demolition waste disposal category determination means and a step of calculating the number of waste bodies by allocating the radioactive waste contained in the dismantling waste after post-dismantling decontamination to waste body containers using waste body container specifications as input information based on the above, and a step of a quantity evaluation means counting the waste bodies for each disposal category based on the number of waste bodies calculated by the waste body number calculation means, and evaluating the quantity of the waste bodies for each disposal category, when the dismantling waste inventory, the radioactive decay period, the decontamination coefficient for the pre-dismantling decontamination, the disposal category concentration of the dismantling waste, the decontamination range and decontamination coefficient for the post-dismantling decontamination,At least one piece of information in the waste container specifications is changed and set. [Effects of the Invention]

[0013] According to an embodiment of the present invention, a waste quantity assessment for each disposal category can be performed in response to at least one variation in the dismantling waste inventory, radioactive decay period, decontamination factor for pre-dismantling decontamination, disposal category concentration of dismantling waste, decontamination range / decontamination factor for post-dismantling decontamination, and waste container specifications. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a block diagram showing the configuration of a radioactive waste quantity evaluation system according to a first embodiment. [Figure 2] 2 is a flowchart showing the processing operations in the radioactive waste quantity evaluation system of FIG. 1; [Figure 3] 2 is a diagram showing an example of a demolition waste inventory that is input information to the radioactive concentration decay calculation means of FIG. 1. [Figure 4] 2 is a diagram showing an example of output information output by the post-demolition, post-decontamination demolition waste disposal classification determination means of FIG. 1. [Figure 5] 2 is a chart showing an example of the quantity for each disposal category output by the quantity evaluation means of FIG. 1. [Figure 6] 2 is a graph showing an example of combinations of disposal category concentrations of demolition waste calculated by the calculation unit of FIG. 1 and the amount of waste generated for each disposal category corresponding to each case. [Figure 7] 2 is a contour diagram showing an example of the waste quantity for each disposal category calculated by the calculation unit in FIG. 1 for any two pieces of input information. [Figure 8] 2 is a graph showing an example of the ratio of the radioactivity concentration of each nuclide in the waste body to the disposal category concentration of the demolition waste calculated by the calculation unit of FIG. 1. [Figure 9] 2 is a graph showing an example of the amount of waste generated for each disposal category during demolition work, calculated by the calculation unit of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [A] First embodiment (Figs. 1 to 9) Fig. 1 is a block diagram showing the configuration of a radioactive waste quantity evaluation system according to the first embodiment. Fig. 2 is a flowchart showing the processing operations in the radioactive waste quantity evaluation system of Fig. 1. The radioactive waste quantity evaluation system 10 shown in Fig. 1 evaluates the quantity of dismantling waste, including radioactive waste, for each disposal category in connection with the formulation of a plan for the treatment and disposal of radioactive waste generated in conjunction with the decommissioning of a nuclear facility (e.g., a nuclear power plant), and is configured with a calculation unit 11, input means 12, and display means 13.

[0016] Here, demolition waste refers to waste generated when a nuclear facility is dismantled, and includes radioactive waste that is low-level radioactive material (radioactive waste that is classified as intermediate depth disposal (L1), pit disposal (L2), or trench disposal (L3) and disposed of underground), as well as waste classified as clearance (CL), which means that the radiation dose caused by the radioactive material is extremely low and does not need to be treated as radioactive material. The radioactive waste quantity evaluation system 10 evaluates not only radioactive waste, but also demolition waste excluding radioactive waste.

[0017] As shown in FIG. 1, the calculation unit 11 is configured to include a radioactivity concentration decay calculation means 14, a pre-demolition post-decontamination radioactivity concentration calculation means 15, a dismantling waste disposal category determination means 16, a post-demolition post-decontamination radioactivity concentration calculation means 17, a post-demolition post-decontamination dismantling waste disposal category determination means 18, a waste body number calculation means 19, and a material quantity evaluation means 20, all of which will be described in detail later.

[0018] The input means 12 inputs the following information into the calculation unit 11 as input information: demolition waste inventory 1, radioactive decay period (cooling period) 2, decontamination coefficient for pre-demolition decontamination 3, disposal category concentration of demolition waste 4, decontamination range and decontamination coefficient for post-demolition decontamination (decontamination range and decontamination coefficient for post-demolition decontamination) 5, and waste container specifications 6, as shown in Figure 2.

[0019] Here, the demolition waste inventory 1, as shown in Figure 3, refers to the equipment name, location of generation, system name, weight, surface area, shape, material, and radioactivity concentration by nuclide (derived from activated contamination and secondary contamination). Activated contamination refers to radioactive contamination due to activation, while secondary contamination refers to radioactive contamination due to the attachment of radioactive materials. Furthermore, the radioactive decay period (cooling period) 2 shown in Figure 2 refers to the storage period for demolition waste at a nuclear facility for the purpose of decaying radioactivity over time.

[0020] Pre-demolition decontamination is decontamination aimed at reducing worker exposure during demolition work. Post-demolition decontamination is carried out with the aim of lowering the disposal category of demolition waste, for example, changing radioactive waste classified as L2 to radioactive waste classified as L3, and changing radioactive waste classified as L3 to demolition waste classified as CL. The decontamination factor 3 for pre-demolition decontamination is defined as the proportion of radioactive material removed by pre-demolition decontamination.

[0021] Disposal category concentration 4 for demolition waste is the standard for radioactivity concentration for accepting demolition waste into each disposal category at a repository. This standard is not specified in the "Regulations on the Business of Class 2 Waste Burial of Nuclear Fuel Material or Materials Contaminated by Nuclear Fuel Material," but is determined by the design of each disposal category at a repository, and there are some disposal sites where this standard has not yet been finalized. Even if waste is considered to be radioactive waste in the L2 disposal category under the above regulations, it may be determined to be radioactive waste in the L1 disposal category depending on the disposal category concentration 4 of the demolition waste.

[0022] In addition, of the decontamination range and decontamination factor for post-dismantling decontamination5, the decontamination range for post-dismantling decontamination is defined as the equipment that will be decontaminated after dismantling. The decontamination factor for post-dismantling decontamination is defined as the proportion of radioactive materials that will be removed by post-dismantling decontamination. In addition, waste container specifications6 are defined as at least one of the size of the waste container, the filling rate of the waste, and the load-bearing capacity of the waste.

[0023] 1 and 2, the radioactivity concentration decay calculation means 14 of the calculation unit 11 calculates the radioactivity concentration of each nuclide in the dismantling waste based on the input information, the demolition waste inventory 1, and further input information, the radioactivity decay period 2, by applying the radioactivity decay effect (step S1). Information including the radioactivity concentration 21 of the dismantling waste (for example, the radioactivity concentration X years after the reactor shut down) as the calculation result by the radioactivity concentration decay calculation means 14 can be displayed on the display means 13 by the calculation unit 11 or by the operator operating the display means 13.

[0024] The pre-demolition decontamination radioactivity concentration calculation means 15 of the calculation unit 11 applies the decontamination effect of pre-demolition decontamination based on the radioactivity concentration 21 of the demolition waste calculated by the radioactivity concentration decay calculation means 14, using the decontamination coefficient 3 for pre-demolition decontamination as input information, and calculates and evaluates the radioactivity concentration of each nuclide in the demolition waste after pre-demolition decontamination (step S2). The application of pre-demolition decontamination and post-demolition decontamination can be set arbitrarily, and by applying them, it becomes possible to confirm the impact that each of pre-demolition decontamination and post-demolition decontamination has on the number of waste packages for each disposal category. In addition, information including the radioactivity concentration 22 of the demolition waste after pre-demolition decontamination, which is the calculation result by the pre-demolition decontamination calculation means 15, can be displayed on the display means 13 by the calculation unit 11 or by the operator operating the display means 13.

[0025] The demolition waste disposal category determination means 16 of the calculation unit 11 uses the disposal category concentration 4 of the demolition waste as input information and determines the disposal category for the demolition waste after decontamination before demolition based on the radioactivity concentration 22 of the demolition waste after decontamination before demolition calculated by the radioactivity concentration after decontamination before demolition calculation means 15 (step S3). Information including the demolition waste disposal category 23, which is the determination result by the demolition waste disposal category determination means 16, can be displayed on the display means 13 by the calculation unit 11 or by the operator operating the display means 13.

[0026] The post-demolition decontamination radioactivity concentration calculation means 17 of the calculation unit 11 applies the decontamination effect of post-demolition decontamination to the demolition waste after pre-demolition decontamination for each disposal category (demolition waste disposal category 23) determined by the demolition waste disposal category determination means 16 using the decontamination range and decontamination coefficient 5 as input information, and calculates and evaluates the radioactivity concentration by nuclide for the demolition waste after post-demolition decontamination (step S4). Information including the radioactivity concentration 24 of the demolition waste after post-demolition decontamination, which is the calculation result by this post-demolition decontamination radioactivity concentration calculation means 17, can be displayed on the display means 13 by the calculation unit 11 or by the operator operating the display means 13.

[0027] The post-demolition and decontamination waste disposal category determination means 18 of the calculation unit 11 uses the disposal category concentration of the demolition waste 4 as input information and determines the disposal category of the demolition waste after decontamination based on the radioactivity concentration 24 of the demolition waste after decontamination calculated by the post-demolition and decontamination radioactivity concentration calculation means 17 (step S5). Information including the demolition waste disposal category 25, which is the determination result by the post-demolition and decontamination waste disposal category determination means 18, is, for example, the location of demolition waste generation, system name, equipment name, weight, radioactivity concentration by nuclide, and disposal category, as shown in Figure 4. Information including the demolition waste disposal category 25 can be displayed on the display means 13 by the calculation unit 11 or by the operator operating the display means 13.

[0028] In addition, for demolition waste before post-demolition decontamination, if the radioactivity concentration is higher than the specified value and it is expected that the disposal category will not change even after post-demolition decontamination, post-demolition decontamination will not be carried out.

[0029] The waste quantity calculation means 19 of the calculation unit 11 first determines whether the decommissioning waste after decommissioning and decontamination is included in the L1, L2, or L3 disposal categories of the decommissioning waste disposal category 25 determined by the decommissioning and decontamination waste disposal category determination means 18 (step S6), and excludes the decommissioning waste after decommissioning and decontamination of the CL disposal category from the calculation of the number of waste bodies because it is not stored in a waste container. Next, the waste quantity calculation means 19 calculates the number of waste bodies for each disposal category by sorting and storing the decommissioning waste after decommissioning and decontamination (i.e., radioactive waste) classified as the L1, L2, or L3 disposal categories of the decommissioning waste disposal category 25 determined by the decommissioning and decontamination waste disposal category determination means 18 into waste containers using waste container specifications 6 as input information (step S7). Information including the number of waste packages 26 calculated by the waste package number calculation means 19 can be displayed on the display means 13 by the calculation unit 11 or by the operator operating the display means 13.

[0030] The quantity evaluation means 20 of the calculation unit 11 totals the number of waste packages for each disposal category L1, L2, and L3 based on the waste package count 26 calculated by the waste package number calculation means 19, and also totals the quantity of dismantling waste for the CL disposal category (hereinafter referred to as CL dismantling waste), thereby evaluating the quantities of these waste packages and the CL dismantling waste (step S8). The information including the quantities 27 of waste packages and CL dismantling waste for each disposal category, which are the processing results (evaluation results) by this quantity evaluation means 20, is at least one of the following: disposal category, waste package weight, waste package radioactivity, waste package container specifications, and number of waste packages, as shown in Figure 5. This information including the quantities 27 of waste packages and CL dismantling waste for each disposal category can be displayed on the display means 13 by the calculation unit 11 or by the operator operating the display means 13.

[0031] Furthermore, in the radioactive waste quantity evaluation system 10 of this first embodiment, at least one of the information contents among the input information, namely, the demolition waste inventory 1, the radioactivity decay period 2, the decontamination coefficient for pre-demolition decontamination 3, the demolition waste disposal category concentration 4, the decontamination range and decontamination coefficient for post-demolition decontamination 5, and the waste container specifications 6, is changed and set by the calculation unit 11 or by the operator operating the input means 12, and the system is configured to sequentially perform calculations and other processes using the radioactivity concentration decay calculation means 14, the pre-demolition post-decontamination radioactivity concentration calculation means 15, the demolition waste disposal category determination means 16, the post-demolition post-decontamination radioactivity concentration calculation means 17, the post-demolition post-decontamination demolition waste disposal category determination means 18, the waste quantity calculation means 19, and the quantity evaluation means 20.

[0032] In other words, the calculation unit 11 of the radioactive waste quantity evaluation system 10 has a function that can output the processing results when any input information is changed as a correlation diagram of the input information. For example, Figure 6 is a correlation diagram that shows the relationship between the combination cases of disposal categories L1, L2, and L3 when the disposal category concentration 4 of demolition waste is changed and the amount of waste generated for each disposal category (e.g., number of pieces) corresponding to each case. Since the disposal category concentration 4 of demolition waste is not a fixed value at present but will be set in the future, it is currently necessary to consider various combinations of values, and this function makes such considerations easier.

[0033] The calculation unit 11 also has the ability to simultaneously reflect changes in multiple pieces of input information and calculate the waste quantity. For example, as shown in Figure 7, any two pieces of input information can be used as variables, and the waste quantities for each of the L1, L2, and L3 disposal categories can be output as a contour diagram. In Figure 7, the calculation unit 11 uses the waste container size and filling rate from the waste container specification 6 as variables, and calculates and evaluates the waste quantities for each of the L1, L2, and L3 disposal categories relative to these values. This makes it easy to confirm the responsiveness of the waste quantities for each of the L1, L2, and L3 disposal categories to changes in the two variables from the waste container specification 6. As another example, it is possible to confirm how the waste quantities for each of the L1, L2, and L3 disposal categories change when the radioactive decay period 2 and the waste container size are used as variables.

[0034] Furthermore, since the timing and location of dismantling waste generation fluctuates depending on the dismantling work plan, such as the dismantling method and period, in association with the decommissioning of a nuclear facility, the computing unit 11 enters information on the dismantling work plan (including the dismantling work period for each location) along with information on the location of generation into the input information, the dismantling waste inventory 1, thereby changing the information content of the dismantling waste inventory 1. As a result, as shown in Figure 9, it becomes possible to evaluate the quantity of waste packages for each disposal category, L1, L2, and L3, that will be generated at any time during the dismantling work period, which will be useful in considering dismantling work plans, such as waste transportation plans and storage plans.

[0035] Furthermore, in the radioactive waste quantity evaluation system 10 of the first embodiment, the calculation unit 11 is configured to be able to further calculate information related to radioactive waste based on information including the processing results of at least one of the radioactivity concentration decay calculation means 14, the pre-demolition post-decontamination radioactivity concentration calculation means 15, the demolition waste disposal category determination means 16, the post-demolition post-decontamination radioactivity concentration calculation means 17, the post-demolition post-decontamination demolition waste disposal category determination means 18, the waste quantity calculation means 19, and the quantity evaluation means 20. In this calculation, the calculation unit 11 may use at least one of the following input information: demolition waste inventory 1, radioactivity decay period 2, decontamination coefficient for pre-demolition decontamination 3, demolition waste disposal category concentration 4, decontamination range and decontamination coefficient for post-demolition decontamination 5, and waste container specifications 6. Furthermore, the at least one processing result mentioned above is at least one of the radioactivity concentration of demolition waste 21, the radioactivity concentration of demolition waste after pre-demolition decontamination 22, demolition waste disposal category 23, the radioactivity concentration of demolition waste after post-demolition decontamination 24, demolition waste disposal category 25, the number of waste bodies 26, the waste bodies per disposal category, and the quantity of CL demolition waste 27.

[0036] In other words, the calculation unit 11 of the radioactive waste quantity evaluation system 10 uses the disposal category concentration 4 of the demolition waste and information including the disposal category 25 of the demolition waste and the number of waste packages 26 to calculate the ratio of the radioactivity concentration of each nuclide in the waste package to the disposal category concentration of the demolition waste, i.e., (radioactivity concentration of each nuclide in the waste package) / (disposal category concentration of the demolition waste), as shown in Figure 8. If the ratio exceeds 1, it means that the radioactivity concentration accepted by the disposal category exceeds the standard. Therefore, this function contributes to the formulation of decommissioning plans by reviewing data (e.g., acquiring actual data, reviewing simulations) and considering effective decontamination methods for nuclides that affect the disposal category of demolition waste (nuclides with the ratio exceeding 1). Note that this function does not apply to the CL disposal category because the classification determination method differs from that for the other disposal categories (L1, L2, L3).

[0037] Furthermore, in the radioactive waste quantity evaluation system 10 of this first embodiment, variables that fluctuate within a specified range can be input as input information, and the calculation unit 11 is configured to output processing results corresponding to the range of the above variables from each of the radioactive concentration decay calculation means 14, the pre-demolition post-decontamination radioactive concentration calculation means 15, the dismantling waste disposal category determination means 16, the post-demolition post-decontamination radioactive concentration calculation means 17, the post-demolition post-decontamination dismantling waste disposal category determination means 18, the waste body number calculation means 19, and the quantity evaluation means 20.

[0038] In other words, it is possible to give any uncertainty to the input information given as a numerical value, and the calculation unit 11 can cause the radioactivity concentration decay calculation means 14, the pre-demolition post-decontamination radioactivity concentration calculation means 15, the dismantling waste disposal category determination means 16, the post-demolition post-decontamination radioactivity concentration calculation means 17, the post-demolition post-decontamination dismantling waste disposal category determination means 18, the waste package number calculation means 19, and the quantity evaluation means 20 to execute calculations according to the uncertainty composition method, and output the uncertainty of the processing results. This makes it possible to support the formulation of decommissioning plans to reduce the uncertainty of the input information, for example, when the uncertainty of the input information has a significant impact on the number of waste packages for each disposal category.

[0039] Here, the arithmetic unit 11 constituting the radioactive waste quantity evaluation system 10 described above may be realized in part or in whole by hardware, for example, by designing it as an integrated circuit. The arithmetic unit 11 may also be realized in software by a processor such as a CPU executing a program that realizes its functions. Information such as the programs, tables, and files that realize each function can be stored in a memory, a recording device such as an SSD (Solid State Drive), or a recording medium such as an IC (Integrated Circuit) card, an SD (Secure Digital) card, or a DVD (Digital Versatile Disc), in addition to being stored on an HD (Hard Disk).

[0040] As configured as above, the first embodiment provides the following effects (1) and (2). (1) When at least one of the information contents among the input information, namely, demolition waste inventory 1, radioactivity decay period 2, decontamination coefficient for pre-demolition decontamination 3, disposal category concentration for demolition waste 4, decontamination range and decontamination coefficient for post-demolition decontamination 5, and waste container specifications 6, is changed and set, the radioactivity concentration decay calculation means 14, radioactivity concentration after pre-demolition decontamination calculation means 15, demolition waste disposal category determination means 16, radioactivity concentration after post-demolition decontamination calculation means 17, demolition waste disposal category determination means 18, waste number calculation means 19, and quantity evaluation means 20 each executes calculations and other processing in response to this setting. Therefore, the evaluation of the quantity of waste for each disposal category of L1, L2, and L3, and the evaluation of the quantity of CL dismantling waste can be easily and accurately performed in response to at least one variation in the dismantling waste inventory 1, radioactive decay period 2, decontamination factor for pre-dismantling decontamination 3, disposal category concentration of dismantling waste 4, decontamination range and decontamination factor for post-dismantling decontamination 5, and waste container specifications 6.

[0041] (2) As input information, variables that fluctuate within a specified range can be input as uncertainties, and the calculation unit 11 is configured to output processing results corresponding to the ranges of the variables from the radioactivity concentration decay calculation means 14, the pre-demolition post-decontamination radioactivity concentration calculation means 15, the dismantling waste disposal category determination means 16, the post-demolition post-decontamination radioactivity concentration calculation means 17, the post-demolition post-decontamination dismantling waste disposal category determination means 18, the waste package number calculation means 19, and the quantity evaluation means 20. Therefore, by checking the effect of the uncertainty of the input information on, for example, the number of waste packages for each disposal category, it is possible to support the formulation of a decommissioning plan to reduce the uncertainty of the input information.

[0042] [B] Second embodiment (see Figures 1 and 2) In the radioactive waste quantity evaluation system 10 of the first embodiment, the demolition waste inventory 1, radioactive decay period (cooling period) 2, decontamination coefficient for pre-demolition decontamination 3, disposal category concentration of demolition waste 4, decontamination range and decontamination coefficient for post-demolition decontamination 5, and waste container specifications 6 are used as input information to calculate the quantity 27 of each waste body for each disposal category L1, L2, and L3, and CL demolition waste.

[0043] In contrast, the radioactive waste quantity evaluation system 29 of the second embodiment is similar to the radioactive waste quantity evaluation system 10 in that it has a calculation unit 11, input means 12, and display means 13, but is configured to be able to output at least one of the following: decommissioning waste inventory 1, radioactive decay period (cooling period) 2, decontamination coefficient for pre-decommissioning decontamination 3, disposal category concentration of decommissioning waste 4, decontamination range and decontamination coefficient for post-decommissioning decontamination 5, and waste container specifications 6, using as input information the waste packages for each disposal category L1, L2, and L3 and the quantities 27 of CL decommissioning waste. In other words, the radioactive waste quantity evaluation system 29 of the second embodiment executes calculations in the reverse direction of the calculation process shown in the radioactive waste quantity evaluation system 10 of the first embodiment.

[0044] That is, in the radioactive waste quantity evaluation system 29, the quantity evaluation means 20 uses the waste bodies for each disposal category L1, L2, L3 and the quantity 27 of CL demolition waste as input information and calculates and outputs the number of waste bodies; the waste body number calculation means 19 calculates and outputs the waste body container specifications 6 from the number of waste bodies calculated by the quantity evaluation means 20; the demolition waste disposal category determination means 18 calculates and outputs the disposal category concentration 4 of the demolition waste based on the disposal category for the demolition waste after decontamination; and the demolition waste after decontamination calculation means 17 calculates and outputs the radioactive concentration of the demolition waste after decontamination It is possible to sequentially carry out the following steps: a step in which the demolition waste disposal category determination means 16 calculates and outputs the decontamination range and decontamination coefficient 5 for post-demolition decontamination based on the radioactivity concentration of the object; a step in which the demolition waste disposal category determination means 16 calculates and outputs the disposal category concentration 4 for the demolition waste based on the disposal category for the demolition waste after pre-demolition decontamination; a step in which the pre-demolition post-decontamination radioactivity concentration calculation means 15 calculates and outputs the decontamination coefficient 3 for pre-demolition decontamination based on the radioactivity concentration of the demolition waste after pre-demolition decontamination; and a step in which the radioactivity concentration decay calculation means 14 calculates and outputs the radioactivity decay period 2 and demolition waste inventory 1 based on the radioactivity concentration of the demolition waste.

[0045] As configured as above, the second embodiment provides the following effect (3). (3) The calculation unit 11 is configured to use the waste packages for each disposal category L1, L2, and L3, and the respective quantities 27 of CL decommissioning waste as input information, and to output at least one of the decommissioning waste inventory 1, radioactive decay period 2, decontamination factor for pre-decommissioning decontamination 3, disposal category concentration of decommissioning waste 4, decontamination range and decontamination factor for post-decommissioning decontamination 5, and waste package specifications 6. Therefore, it is possible to evaluate at least one of the decommissioning waste inventory 1, radioactive decay period 2, decontamination factor for pre-decommissioning decontamination 3, disposal category concentration of decommissioning waste 4, decontamination range and decontamination factor for post-decommissioning decontamination 5, and waste package specifications 6 that are required to satisfy the respective quantities 27 of the waste packages for each disposal category L1, L2, and L3, and CL decommissioning waste.

[0046] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, changes, and combinations can be made without departing from the spirit of the invention. Furthermore, such substitutions, changes, and combinations are included in the scope and spirit of the invention, and are also included in the inventions and their equivalents as set forth in the claims.

[0047] For example, in the flowchart shown in Fig. 2 of the first embodiment, steps S1 to S8 are executed in series, but the order of the steps is not necessarily fixed, and the order of some steps may be reversed, or some steps may be executed in parallel with other steps. Specifically, when evaluating by applying a radioactive decay period (cooling period), the radioactive decay period may be set before pre-demolition decontamination as in step S1, but the radioactive decay period may be set after step S2 after pre-demolition decontamination by replacing or adding it, or the radioactive decay period may be set after step S4 after post-demolition decontamination by replacing or adding it. [Explanation of symbols]

[0048] 1...Demolition waste inventory, 2...Radioactivity decay period (cooling period), 3...Decontamination coefficient for decontamination before demolition, 4...Disposal category concentration for demolition waste, 5...Decontamination range and decontamination coefficient for decontamination after demolition, 6...Waste container specifications, 10...Radioactive waste quantity evaluation system, 11...Calculation unit, 14...Radioactivity concentration decay calculation means, 15...Radioactivity concentration after decontamination before demolition calculation means, 16...Demolition waste disposal category determination means, 17...Radioactivity concentration after decontamination calculation means , 18...Means for determining disposal category of demolition waste after decontamination after dismantling, 19...Means for calculating number of waste bodies, 20...Quantity evaluation means, 21...Radioactivity concentration of demolition waste, 22...Radioactivity concentration of demolition waste after decontamination before dismantling, 23...Dismantling waste disposal category, 24...Radioactivity concentration of demolition waste after decontamination after dismantling, 25...Dismantling waste disposal category, 26...Number of waste bodies, 27...Waste bodies for each disposal category, each quantity of CL demolition waste, 29...Radioactive waste quantity evaluation system

Claims

1. A radioactive waste quantity evaluation system that evaluates the quantity of radioactive waste for each disposal category in relation to the formulation of plans for the treatment and disposal of radioactive waste generated in the decommissioning of nuclear facilities, A radioactivity concentration decay calculation means for calculating the radioactivity concentration of the demolition waste by applying a radioactivity decay effect using a radioactivity decay period as input information based on the demolition waste inventory including the radioactive waste, which is input information; A pre-demolition post-decontamination radioactivity concentration calculation means for calculating the radioactivity concentration of the demolition waste after pre-demolition decontamination based on the radioactivity concentration calculated by the radioactivity concentration decay calculation means, using the decontamination coefficient of pre-demolition decontamination as input information to apply the decontamination effect by pre-demolition decontamination; A demolition waste disposal category determination means for determining the disposal category of the demolition waste after decontamination before demolition based on the radioactivity concentration of the demolition waste after decontamination before demolition calculated by the radioactivity concentration calculation means after decontamination before demolition using the disposal category concentration of the demolition waste as input information; A post-demolition decontamination radioactivity concentration calculation means for calculating the radioactivity concentration of the demolition waste after pre-demolition decontamination for each disposal category determined by the demolition waste disposal category determination means, by applying the decontamination effect by post-demolition decontamination using the decontamination range and decontamination coefficient of post-demolition decontamination as input information; A post-demolition and decontamination waste disposal category determination means for determining a disposal category for the demolition waste after decontamination based on the radioactivity concentration of the demolition waste after decontamination calculated by the post-demolition and decontamination radioactivity concentration calculation means, using the disposal category concentration of the demolition waste as input information; a waste quantity calculation means for calculating the number of waste bodies by allocating the radioactive waste contained in the dismantling waste after decontamination to waste containers based on the determination result of the dismantling and decontamination waste disposal classification determination means and using waste container specifications as input information; a waste quantity evaluation means for tallying up the waste for each disposal category based on the number of waste calculated by the waste quantity calculation means, and evaluating the quantity of the waste for each disposal category; A radioactive waste quantity evaluation system characterized in that at least one of the information contents among the demolition waste inventory, the radioactive decay period, the decontamination coefficient for the pre-demolition decontamination, the disposal category concentration of the demolition waste, the decontamination range and decontamination coefficient for the post-demolition decontamination, and the specifications of the waste container can be changed and set.

2. The radioactive waste quantity evaluation system according to claim 1, characterized in that information relating to radioactive waste is further calculated based on the processing results of at least one of the radioactivity concentration decay calculation means, the pre-demolition post-decontamination radioactivity concentration calculation means, the dismantling waste disposal category determination means, the post-demolition post-decontamination radioactivity concentration calculation means, the post-demolition post-decontamination dismantling waste disposal category determination means, the waste body number calculation means, and the quantity evaluation means.

3. 3. A radioactive waste quantity evaluation system as described in claim 1 or 2, characterized in that the quantity of waste bodies for each disposal category evaluated by the quantity evaluation means is configured to include at least one of the number of waste bodies for each disposal category, the weight of the waste bodies, and the amount of radioactivity of the waste bodies.

4. 3. The radioactive waste quantity evaluation system according to claim 1, wherein the waste specifications are configured to include at least one of the size of the waste container, the filling rate of the waste container, and the load-bearing capacity of the waste container.

5. The radioactive waste quantity evaluation system according to claim 1 or 2, characterized in that a variable that fluctuates within a specified range can be input as the input information, and the processing results corresponding to the range of the variable are output by each of the radioactivity concentration decay calculation means, the pre-demolition post-decontamination radioactivity concentration calculation means, the demolition waste disposal category determination means, the post-demolition post-decontamination radioactivity concentration calculation means, the post-demolition post-decontamination demolition waste disposal category determination means, the waste body number calculation means, and the quantity evaluation means.

6. A method for evaluating the quantity of radioactive waste for each disposal category in relation to the formulation of a plan for the treatment and disposal of radioactive waste generated in the decommissioning of a nuclear facility, A step of applying the radioactivity decay effect using the radioactivity decay period as input information based on the demolition waste inventory including the radioactive waste, which is input information of the radioactivity concentration decay calculation means, and calculating the radioactivity concentration of the demolition waste; A step in which a radioactive concentration calculation means after pre-demolition decontamination calculates the radioactive concentration of the demolition waste after pre-demolition decontamination based on the radioactive concentration calculated by the radioactive concentration decay calculation means, using the decontamination coefficient of pre-demolition decontamination as input information and applying the decontamination effect by pre-demolition decontamination; A step in which a demolition waste disposal category determination means determines the disposal category of the demolition waste after pre-demolition decontamination based on the radioactivity concentration of the demolition waste after pre-demolition decontamination calculated by the pre-demolition decontamination radioactivity concentration calculation means, using the disposal category concentration of the demolition waste as input information; A post-demolition decontamination radioactivity concentration calculation means applies the decontamination effect of post-demolition decontamination to the demolition waste after pre-demolition decontamination for each disposal category determined by the demolition waste disposal category determination means using the decontamination range and decontamination coefficient of post-demolition decontamination as input information, and calculates the radioactivity concentration of the demolition waste after post-demolition decontamination; A step in which a post-demolition decontamination waste disposal category determination means determines a disposal category for the demolition waste after decontamination based on the radioactivity concentration of the demolition waste after decontamination calculated by the post-demolition decontamination radioactivity concentration calculation means, using the disposal category concentration of the demolition waste as input information; a step in which a waste quantity calculation means calculates the number of waste bodies by allocating the radioactive waste contained in the dismantled waste after dismantling and decontamination to waste containers using waste container specifications as input information based on the determination result of the dismantled waste disposal classification determination means after dismantling and decontamination; a quantity evaluation means for tallying up the waste packages for each disposal category based on the number of waste packages calculated by the waste package number calculation means, and evaluating the quantity of the waste packages for each disposal category; A method for evaluating the quantity of radioactive waste, characterized in that at least one piece of information content is changed and set among the decommissioning waste inventory, the radioactive decay period, the decontamination coefficient for the pre-decommissioning decontamination, the disposal category concentration of the decommissioning waste, the decontamination range and decontamination coefficient for the post-decommissioning decontamination, and the specifications of the waste container.

7. A method for evaluating the quantity of radioactive waste for each disposal category in relation to the formulation of a plan for the treatment and disposal of radioactive waste generated in the decommissioning of a nuclear facility, a step in which a quantity evaluation means calculates and outputs the number of waste packages using the quantity of waste packages for each disposal category as input information; a waste quantity calculation means for calculating and outputting waste container specifications based on the number of wastes calculated by the waste quantity evaluation means; A step in which a post-demolition and decontamination waste disposal category determination means calculates and outputs a disposal category concentration of the demolition waste based on the disposal category for the demolition waste after demolition and decontamination; A step in which a post-demolition decontamination radioactivity concentration calculation means calculates and outputs a decontamination range and decontamination coefficient for post-demolition decontamination based on the radioactivity concentration of the demolition waste after post-demolition decontamination; A step in which a demolition waste disposal category determination means calculates and outputs a disposal category concentration of the demolition waste based on the disposal category of the demolition waste after pre-demolition decontamination; A step in which a pre-demolition decontamination radioactivity concentration calculation means calculates and outputs a decontamination coefficient for pre-demolition decontamination based on the radioactivity concentration of the demolition waste after pre-demolition decontamination; A method for evaluating the quantity of radioactive waste, characterized by sequentially performing the steps of: a radioactivity concentration decay calculation means calculating and outputting the radioactivity decay period and demolition waste inventory based on the radioactivity concentration of the demolition waste.

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