JP6626398B2 - Disposal process management device and disposal process management method - Google Patents

Description

  The present invention relates to a disposal process management device and a disposal process management method.

  When planning the disposal process of a nuclear power plant, a more thorough planning is required, as compared with plants in other fields, taking into account the exposure of workers to radioactivity. Furthermore, the construction of the final disposal site for radioactive waste has been delayed in Japan, which complicates the disposal process, such as temporarily storing radioactive waste in nuclear power plants. Therefore, a system has been proposed that supports the planning of the disposal process, focusing on the amount of radiation exposure.

Patent Literature 1 discloses a system for calculating an arrangement position according to the intensity of the dose rate of each device / pipe as a method of storing dismantled waste to which a high level of radioactive substance is attached.
Patent Literature 2 describes a support device for easily grasping the number of storage containers for radioactive waste.
Patent Literature 3 describes an evaluation method for quickly and highly accurately measuring and evaluating a radiation dose rate distribution in a work place.
Patent Literature 4 describes a work plan support device that focuses on shielding radiation.

JP 2015-230223 A JP 2015-087300 A JP-A-6-088873 JP 2014-006645 A

  Due to the peculiarity of the operation of the disposal process of a nuclear power plant, there is a restriction that resources for disposal such as a work place and the number of workers cannot be easily increased. Under this constraint, a more thorough and detailed plan is required to advance the disposal process more safely and at lower cost while taking into account the radiation exposure. It is difficult for a human such as an administrator to manually draft this plan, and support by a computer is expected.

On the other hand, one of the characteristics of radioactive waste is that the radioactivity of the radioactive material contained therein decreases over time (there is a half-life of nuclide). Some radioactive substances have a high radioactivity concentration at the beginning of generation, but have a short half-life. Therefore, by making use of the characteristics (half-life) of each radioactive material and planning the disposal process of a nuclear power plant, it is possible to create a disposal plan at a lower cost.
However, in each of the prior arts such as Patent Documents 1 to 4 described above, no plan has been made on the assumption of a half-life for each radioactive substance in advance. Therefore, even if the radioactivity concentration becomes safe after a short wait, the work starts immediately and the schedule is wasted.

  Therefore, a main object of the present invention is to support the planning of an efficient disposal process utilizing the characteristics of radioactive materials.

In order to solve the above problems, the disposal process management device of the present invention
For each radioactive substance contained in the radioactive waste, a storage unit in which half-life information indicating the degree of decrease in radioactivity concentration of the radioactive substance over time is registered in advance,
For each disposal process of the radioactive waste, an input unit that receives input in association with the information of the radioactive waste that is the disposal target,
For each input predetermined period, a cost calculation unit that determines the required cost of each disposal process executed in that period by referring to the half-life information,
When the required cost for each of the obtained periods exceeds a predetermined limit value, at least one of the discarding processes performed in the exceeded period is extended so as to be performed after the exceeded period. And a process extension portion.
Other means will be described later.

  According to the present invention, it is possible to support the planning of an efficient disposal process utilizing the characteristics of a radioactive substance.

It is a lineblock diagram of a disposal process management system concerning one embodiment of the present invention. It is a flowchart which shows the process extension process of the process management apparatus concerning one Embodiment of this invention. It is an explanatory view showing an example of work place information and waste information concerning one embodiment of the present invention. It is a flow chart which shows an example of a disposal process performed by an operator concerning one embodiment of the present invention. 6 is a Gantt chart illustrating an example of process information according to an embodiment of the present invention. It is a graph which shows the time decay of the radioactivity density for every radioactive material of the waste information concerning one Embodiment of this invention. It is an explanatory view showing worker information concerning one embodiment of the present invention. It is explanatory drawing which shows the period accumulation value concerning one Embodiment of this invention. It is an explanatory view showing extension information concerning one embodiment of the present invention.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a configuration diagram of the disposal process management system. The disposal process management system includes the process management device 1, its input device 8, and its display device 9.
The process management apparatus 1 is configured as a computer having a CPU (Central Processing Unit), a memory, a storage unit (storage unit) such as a hard disk, and a network interface.
In this computer, the CPU operates a control unit (control unit) configured by each processing unit by executing a program (also referred to as an application or an abbreviation for an application) read from the memory.

The process management device 1 is configured to include an input unit 11, a pile value calculation unit 12, a process extension unit 13, a database 20, and a storage unit for calculation result data (period pile value 31, extension information 32). .
The input unit 11 receives input of various data to be stored in the database 20 from the input device 8 or the like, and stores the input data in the database 20.
The pile-up value calculator 12 calculates the period pile-up value 31 (discarded) for a predetermined period based on the data stored in the database 20 for each type of process restriction, such as the cost limit and the number of workers, input by the input unit 11. Required cost of the process).
The process extension unit 13 smoothes the period accumulation value 31 by extending a process scheduled to be executed during a period in which the period accumulation value 31 exceeds the process limit, and reduces the period in which the process restriction is exceeded.

  The database 20 stores information on a disposal process such as process information 21, work place information 22, waste information 23, and worker information 24. For example, as a first process (process information 21), worker A dismantles worker information 24 at B nuclear power plant (work site information 22) and plant C (waste information 23). Each piece of process information 21 is associated with each piece of information relating to that process.

The database 20 also has a basic editing function for data managed in the database 20 as exemplified below, as a database management system (DBMS). In this editing function, all data may be input by the administrator, or based on a part of the input data and the calculation formula registered in advance, the data which has not been input is obtained by automatic calculation. Is also good.
Editing function of process information 21 (see FIG. 5 for details). For example, the total cost such as labor cost and equipment cost when 100 workers execute plant dismantling as the first process is set.
Editing function of work place information 22 (for details, see FIG. 3). For example, a vacant lot adjacent to the B nuclear power plant is set as a temporary storage place.
Editing function of waste information 23 (see FIG. 3 for details). For example, setting the radioactivity concentration of the radioactive waste resulting from dismantling the C plant.
Editing function of the worker information 24 (for details, see FIG. 7). For example, setting the exposure of worker A in March 2016.

FIG. 2 is a flowchart illustrating a process extension process of the process management device 1.
In step S101, the input unit 11 receives input of various data stored in the database 20. As described above, in addition to the information describing the disposal process such as the work place information 22, the input unit 11 also includes a process restriction related to the disposal process such as “Restrict the disposal budget within 1 billion yen in January 2016”. Accept. Hereinafter, an example of the process restriction will be listed.
-Whether the air dose rate of the work place indicated by the work place information 22 exceeds the workable degree (restriction of the degree of contamination). For example, if high-level radioactive waste is densely arranged in a small place, the air dose rate in that place will be high, and workers will not be able to enter that place.
Whether or not the storage capacity of the storage container for the radioactive waste indicated by the waste information 23 exceeds the space capacity (volume utilization rate) of the work place indicated by the work place information 22 (restriction on storage capacity).
Whether or not the limit on the number of workers indicated by the worker information 24 is exceeded (number of workers). For example, the number of workers who can work at the same time is limited due to the small work place, or the number of workers who can be recruited when assigning the number of workers recruited in advance to each work place has an upper limit.

  In step S111, the process extension unit 13 sequentially selects a period to be extended this time (hereinafter, a target period). For example, when the period length is one month, the periods are selected in chronological order, such as January 2016 → February 2016 → March 2016 →. In the following loops (S111 to S116), the process extension unit 13 calculates whether or not to extend each process executed during the target period, and to what extent the process is extended when extending. .

In step S112, the pile-up value calculation unit 12 calculates a pile-up value for each radioactivity level, which is the evaluation value, in order to determine whether or not the process limit of step S101 is exceeded, and then calculates a pile-up value for each radioactivity level. The pile-up values are summed to form one period pile-up value 31. For example, in order to determine whether the number of people in the temporary storage near the nuclear power plant B exceeds the number of persons in January 2016, the pile volume calculation unit 12 identifies the worker who performs the process at that time and place in the process information 21. Is specified from the worker information 24 corresponding to. Then, the pile value calculator 12 reads the radioactivity level of the radioactive waste to be worked from the waste information 23 corresponding to the process information 21 for each of the identified workers, thereby performing the work on the high-level radioactive waste. And the number of workers of medium-level radioactive waste and the number of workers of low-level radioactive waste, respectively.
When calculating the period pile value 31, the pile value calculator 12 refers to the radioactivity concentration (half-life information) of each radioactive substance in the target period described later in FIG. The radioactivity level of an object can be specified.

  As S113, the process extension unit 13 determines whether or not the period accumulation value 31 in S112 exceeds the process limit value in S101. If Yes in S113, proceed to S114; if No, proceed to S116. For example, when the period piled value 31 of “high level → 20 people, middle level → 50 people, low level → 40 people, a total of 110 people is required” is obtained in S112, and “a total of 100 workers can be prepared” in S101. , The process proceeds to S114.

  In step S114, the process extension unit 13 reads from the process information 21 the processes performed in the target period in which the limit has been exceeded in step S113, and from the read processes (extended candidate processes), uses the extension information 32 (this extension). And the extension period in the process). The extension period may be calculated, for example, so as to be later than the target period in which the limit has been exceeded (so that there is no overlapping period between the target period and the process period). That is, the start date and time of the process to be extended this time may be postponed so as to be later than the target period in which the limit has been exceeded.

The following describes the priorities of the steps to be extended (conditions that facilitate the selection of an extended step).
A process in which the data component (degree of influence) in the period accumulation value 31 has a higher ratio is preferentially selected as a process to be extended. For example, when the number of persons exceeds the limit, a step requiring a larger number of persons is preferentially selected as a step to be extended.
-A process with a higher radioactivity level, that is, a process with radioactive waste having a higher radioactivity level, is preferentially selected as a process to be extended.
-A process with a longer overlapping period between the target period and the process period is preferentially selected as a process to be extended. On the other hand, if the target period is January 2016 and the candidate process is from January 30, 2016 to February 10, 2016, the overlapping period is only two days. Such a process in which the overlapping period is short has a small degree of influence on the target period. Therefore, although it is a candidate to be extended, it is not given priority.

  In S115, the process extension unit 13 extends the extension process determined in S114 by the extension period. As a result, in the target period selected in the current loop of S111, the excess of the limit is resolved. Note that the pile-up value calculator 12 may recalculate the period pile-up value 31 with reference to the half-life information in FIG. For example, when the process of storing and storing a certain high-level radioactive waste in a storage container is extended, the radioactive material is attenuated to a medium level as time elapses in the extension. In this case, the lower the radioactivity level, the smaller the surface dose rate, and thus the size of the storage container can be reduced. Therefore, the space capacity (space utilization rate), which is the period piled value 31, can be reduced by recalculation.

In S116, the process extension unit 13 ends the loop from S111.
In step S121, the database 20 (DBMS) displays each process extended in S115 (or has not been extended because of exceeding the limit) on the display device 9 in a Gantt chart format or the like. To accept input such as confirmation work and adjustment work.

FIG. 3 is an explanatory diagram showing an example of the work place information 22 and the waste information 23.
The waste information 23 is information on radioactive waste containing radioactive material (contaminated by radioactive material). The waste information 23 includes, for example, the radioactivity concentration of the radioactive waste, the radioactivity level obtained by dividing the radioactivity concentration by a predetermined level, the surface dose rate of the radioactive waste, and the like. Further, the waste information 23 may include shape information (3D model) of the radioactive waste. Hereinafter, the tank-shaped device 101 in the plant will be described as an example of a 3D model.

  The worker dismantles the device 101 along the device cutting line shown by the broken line to produce radioactive waste. The radioactive waste is stored in a waste storage container 102. The waste storage container 102 stores waste that may have been contaminated with radioactive material during the operation of the plant, or that may have been activated by neutron / γ-ray radiation from fuel. You. Here, as for the size of the waste storage container 102, it is general that a dangerously radioactive waste (higher radioactivity level) requires a larger container.

  The work place information 22 includes information on the work place where radioactive waste is to be treated, in addition to the work place information (address, latitude and longitude), the work place area information (the size and shape on the map), and the work place information. Type (dismantling site where the device 101 is dismantled, temporary storage location of the waste storage container 102, final disposal site that is the transport destination from the temporary storage location), air dose rate of radiation emitted at the work place, and its radiation May be included.

  FIG. 3 illustrates a temporary storage location 103 as the work location information 22. The waste storage container 102 carried in from the carry-in entrance 103c has a high-level control area 103a according to the level of the radioactivity [Bq] contained in the waste or the surface dose rate [mSv / h] of the waste storage container 102. Alternatively, it is temporarily stored in the low-level management area 103b. Then, when the final disposal site can be accepted and the waste transport truck and ship become available, the waste storage container 102 is put into the transport container from this temporary storage location and transported.

  FIG. 4 is a flowchart illustrating an example of a disposal process performed by an operator. The flow on the left side of FIG. 4 shows steps for high-level radioactive waste, and the flow on the right side of FIG. 4 shows steps for low-level radioactive waste. Hereinafter, each process of FIG. 4 is performed by an operator.

  At the dismantling site of the piping and equipment of the plant, the piping and equipment are cut and stored in a waste storage container (S11). The waste or the storage container is temporarily placed (S12), and cut secondarily so as to be easily packed in the waste storage container or to be easily decontaminated after secondary disassembly (S13). Thereafter, low-level waste is decontaminated after dismantling (S23). Next, high-level waste is filled with mortar (S14) and temporarily stored (S15).

  In addition, low-level waste after decontamination after demolition is temporarily stored after filling with sand (S24) (S25). The radioactivity is measured for the waste containers having any radioactivity level (S16, S26). As a result of the radioactivity measurement, if the radioactivity level predicted from the surface dose rate is high (Yes in S17 or No in S27), the container is managed in the high-level waste management facility by the unloading work (S18). Is performed (S19). If the radioactivity level is low as a result of the measurement (No in S17 or Yes in S27), the container is managed in the low-level waste management facility by carrying out work (S28) (S29).

FIG. 5 is a Gantt chart illustrating an example of the process information 21. The Gantt chart 111 shows a part of the dismantling process, and the Gantt chart 112 shows the whole dismantling process.
The disassembly process indicated by the Gantt chart 111 is a preparation (work) process → a disassembly process A for cutting and moving objects such as piping and equipment → a disassembly that further dismantles the cut disassembly and places it in a waste storage container. It is a set of steps executed in the order of step B → step of carrying out the waste put in the waste storage container.
The disposal process indicated by the Gantt chart 112 is a synthesis of the disassembly process indicated by the Gantt chart 111, as exemplified in the disposal process shown in FIG. 4, and is defined over the entire period of decommissioning. This example illustrates the fuel removal process, system decontamination process, pollution investigation process, dismantling preparation process, high-contamination section dismantling process, building dismantling process, low-contamination section dismantling process, and radioactive waste treatment and disposal process after the plant operation stops. ing.
By preparing a Gantt chart to hold down the entire period of decommissioning in this way, it is possible to calculate the total cost related to decommissioning from the amount of radioactive waste generated during the period and personnel costs.

FIG. 6 is a graph showing the time decay (half-life information) of the radioactivity concentration for each radioactive substance in the waste information 23. The half-life information is input in advance by, for example, an administrator. Here, a graph is shown for each nuclide such as cobalt 60 (Co-60), Ni-63, H-3, and Ni-59 as radioactive substances mainly generated by activation around the reactor during operation of the plant. ing.
Of these nuclides, cobalt-60 (Co-60) is produced more than other nuclides that co-occur because the radioactivity concentration [Bq / t] decays with a half-life of about 5 years after the shutdown. Although the radioactivity concentration at the time is high, the radioactivity concentration reverses and decreases as the elapsed year [y] becomes longer. Thus, initially, Co-60 occupies a major part of the radioactivity concentration to be considered, but after several decades it will be necessary to consider the effects of other nuclides. In other words, by extending the work on the cobalt 60, the effect of reducing the radioactivity concentration is increased.

  Hereinafter, a method of calculating a period in which the process extension unit 13 extends the process of the radioactive waste containing cobalt 60 will be exemplified. The radioactivity concentration at the time of generation of cobalt 60 (elapsed year = 0) is 10 13 [Bq / t], and it is assumed that it is determined at this time that the contamination degree limit has been exceeded. Then, a case is considered where the restriction on the degree of contamination is passed when the radioactivity concentration of cobalt 60 has attenuated to a reference value (10 11 [Bq / t]). At this time, the process extension unit 13 obtains a point at which the graph line of cobalt 60 becomes a reference value of the radioactivity concentration (reference numeral 121), and obtains an elapsed year of the point (reference numeral 122). Thus, the extension period 123 can be obtained.

FIG. 7 is an explanatory diagram showing the worker information 24.
The table 121 indicating the worker information 24 includes, for each worker ID, a process ID of a process executed by the worker, a work time related to the process, an exposure amount of the process alone, and the process. Dismantled materials (radioactive waste) are managed in association with each other.
The pile-up value calculator 12 creates an integrated exposure dose graph 122 for each worker by integrating the exposure doses of records having the same worker ID in the table 121. Similarly, an accumulation amount graph of the operation time (operation amount) can be created from the table 121.

With the passage of time, the exposure of the worker increases. If it is predicted that the planned work exposure limit will be exceeded during the demolition work, the exposure dose can be given as a material for determining that the demolition work is not appropriate. In this case, it is necessary to change the disassembly process so as not to exceed the limit value by taking measures such as reducing the exposure dose and the air dose rate at the work place, and replacing the work process.
Thus, the display device 9 of the process management apparatus 1 displays such an integrated exposure dose graph 122 on a screen, so that a process manager can grasp the risk of the exposure dose for each worker.

FIG. 8 is an explanatory diagram illustrating the period accumulation value 31.
The bar graph 131 displays the component values of the period accumulation value 31 for each radioactivity level (here, three levels of high level, middle level, and low level). The value of the vertical axis (Y axis) of the bar graph 131 varies depending on the type of restriction, and includes the number of persons, the space, the pollution, and the cost as described above. In this case, the excess period of the limit occurs in the middle stage and the final stage of the process, respectively, so it is necessary to extend the process performed in the excess period.

In the upper part of the display screen 132, in addition to the bar graph 131 (period pile value), the time axis is associated with the process (such as the Gantt chart 112), and the radioactivity (such as air dose rate) for each period. Is also displayed. The display at the top is in a tab window format for each scenario, and different scenarios can be switched and displayed by clicking the mouse on the tab fields displayed as “Scenario 1” and “Scenario 2”. Note that a scenario is a variation of a set of steps shown in the Gantt chart 112 or the like.
In addition, the process management apparatus 1 may use, for example, a highlight display (color change, blinking, etc.) of the excess period or a warning when one or more excess periods exist, as a warning for notifying the administrator of the existence of the excess period. For example, a warning sound may be reproduced.

  Further, on the lower part of the display screen 132, as various buttons for operating these screen elements, an input button of S101 (an input button of process information 21, an input button of work place information 22, and an input button of waste information 23) , Worker information 24 input button, restriction information input button), a start button for the extension processing calculation from S111, and a start button for the adjustment in S121.

FIG. 9 is an explanatory diagram showing the extension information 32. FIG. 9 is a table format that makes it easy to compare the left column before extension and the right column after extension, and elements located in the same column have the same time axis (X axis).
The first row “step” is a set of steps exemplified in the Gantt chart 112 and the like.
The “exposure dose” in the second row is the total sum of the exposure dose (the fourth column of the table 121) of the worker in charge of the process shown in the first row.
The third row “Work pile” is the total sum of the working time (third column of the table 121) of the worker in charge of the process shown in the first row.
The “radioactivity” in the fourth row is the sum of the radioactivity of the waste to be subjected to the process shown in the first row, and is obtained from the waste information 23.
The fifth row “waste pile” is the total volume of the waste storage container 102 in which the waste to be processed in the first row is stored, and is obtained from the waste information 23.

  The process extension unit 13 determines that the process set 141 to be extended is to be extended to the process set 142 (5 years) as the extension information 32 in S114 of FIG. As a result, it is possible to modify the disposal plan so that the period before the extension (2015) and the period after the extension (2020) fall below the limit value indicated by the broken line. In other words, the restriction on the third row “Work pile” (shortage of workers) and the fifth row “Waste pile” (lack of storage space) can be eliminated by the extension process.

  Here, in FIG. 9, there are two types of period pile values 31 in the third row “Work pile” and the fifth row “Waste pile”. As described above, when a plurality of types of the period piled values 31 exist, even if one of the period piled values 31 has passed the limit, the other period piled value 31 may be over the limit. Accordingly, the process extension unit 13 separately determines whether or not each of the plurality of types of required costs exceeds the limit, and adjusts the plurality of types of determination results to determine a period in which the number of required costs is exceeded. For example, when all types of the period piled values 31 pass the limit, it may be determined that the limit is not exceeded, or the type of the period piled value 31 determined in advance by the administrator to be important may be determined to be the limit. May be determined not to exceed the limit.

The present invention is not limited to the above-described embodiment, but includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described above.
In addition, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of one embodiment can be added to the configuration of another embodiment.
Further, for a part of the configuration of each embodiment, it is possible to add / delete / replace another configuration. In addition, each of the above-described configurations, functions, processing units, processing means, and the like may be partially or entirely realized by hardware by, for example, designing an integrated circuit.
In addition, the above-described configurations, functions, and the like may be implemented by software by a processor interpreting and executing a program that implements each function.

Information such as programs, tables, and files that realize each function is stored in a memory, hard disk, recording device such as SSD (Solid State Drive), IC (Integrated Circuit) card, SD card, DVD (Digital Versatile Disc), etc. Recording media.
In addition, control lines and information lines indicate those which are considered necessary for explanation, and do not necessarily indicate all control lines and information lines on a product. In fact, it may be considered that almost all components are connected to each other.
Further, the communication means connecting each device is not limited to the wireless LAN, but may be changed to a wired LAN or other communication means.

DESCRIPTION OF SYMBOLS 1 Process management apparatus 8 Input device 9 Display device 11 Input part 12 Stack value calculation part (cost calculation part)
13 Process extension part 20 Database 21 Process information 22 Work place information 23 Waste information 24 Worker information 31 Period pile 32 Extension information

Claims (6)

For each radioactive substance contained in the radioactive waste, a storage unit in which half-life information indicating the degree of decrease in radioactivity concentration of the radioactive substance over time is registered in advance,
For each disposal process of the radioactive waste, an input unit that receives an input in association with the information of the radioactive waste that is the disposal target,
For each input predetermined period, a cost calculation unit that determines the required cost of each disposal process executed in that period by referring to the half-life information,
When the required cost for each of the obtained periods exceeds a predetermined limit value, at least one of the discarding processes performed in the exceeded period is extended so as to be performed after the exceeded period. A waste process management device, comprising: The cost calculation unit, for the required cost for comparing with the predetermined limit value, separately calculates a plurality of types of costs,
The process extension unit determines whether or not the predetermined limit value has been exceeded for each of the plurality of types of required costs, and adjusts the plurality of types of determination results to determine the excess period. The disposal process management device according to claim 1. The process extension unit, when the air dose rate of the work place handling the radioactive waste exceeds the workable degree, to determine that the predetermined limit value has been exceeded in the predetermined period. A disposal process management device according to claim 1 or claim 2. The process extension unit determines that the number of workers required for each disposal process performed in a predetermined period exceeds the predetermined limit value in the predetermined period when the number of workers exceeds the allocatable number. The disposal process management device according to claim 1 or 2, wherein: The process extension unit, when the sum of the volumes of the containers in which the radioactive waste to be subjected to each disposal process performed in a predetermined period is stored exceeds the volume of a storable space, The disposal process management device according to claim 1, wherein it is determined that the predetermined limit value is exceeded during a period. The disposal process management device has a storage unit, an input unit, a cost calculation unit, and a process extension unit,
In the storage unit, for each radioactive substance contained in the radioactive waste, half-life information indicating the degree of decrease in the radioactivity concentration of the radioactive substance over time is registered in advance,
The input unit, for each disposal process of the radioactive waste, accepts input in association with the information of the radioactive waste that is the disposal target,
The cost calculation unit, for each of the input predetermined period, the required cost of each discarding process performed in that period is obtained by referring to the half-life information,
When the required cost for each of the obtained periods exceeds a predetermined limit value, the process extension unit performs at least one of the discarding processes performed in the excess period after the excess period. Disposal process management method, characterized in that it is extended to be executed.