JP7820328B2 - Dose estimation device, work plan update system, dose estimation method, and work plan update method - Google Patents

Description

The present invention relates to a dose estimation device, work plan update system, dose estimation method, and work plan update method that are suitable for rationally carrying out work involving the safe handling of radioactive materials while adhering to the upper dose limit that must be observed for work safety.

Patent Document 1 describes a radiation monitoring device that includes an area radiation monitor that measures the air dose rate, and a signal processing device that calculates the dust radiation concentration in the vicinity of the area radiation monitor from the air dose rate measured by the area radiation monitor, based on a correlation equation between the air dose rate and dust radioactivity concentration that has been determined in advance.

Patent Document 2 describes a local neutron multiplication characteristic measuring device that includes a first neutron detection system having a first neutron detector that mainly detects thermal neutrons and a first moderator member arranged around the detector; a second neutron detection system having a second neutron detector that mainly detects thermal neutrons and a second moderator member arranged around the detector and a flat neutron absorbing member arranged between the second moderator member and the fuel debris; and a calculation unit that receives as input the output from the first neutron detector and the output from the second neutron detector and calculates the reactivity of the target portion.

JP 2014-48132 A JP 2016-80666 A

Facilities that handle radioactive materials include nuclear power plants, nuclear fuel processing and manufacturing facilities, waste treatment facilities, accelerator facilities, medical facilities, pharmaceutical facilities, and facilities with controlled areas for radioactive materials.

Facilities that handle such radioactive materials require safe management of the radioactive materials. For example, in nuclear power plants, radioactive materials, including nuclear material, are usually stored underwater as fuel assemblies, and handling operations are carried out under strict safety management.

At facilities that handle and dispose of radioactive waste, some work objects have irregular shapes and the radioactivity concentration of each work object varies, so estimates with a sufficient margin are set before handling the object.

When handling work objects containing such radioactive materials, measures are taken to prevent the dispersion of radioactive materials and to mitigate the amount of dispersion, preventing the dispersion of materials from being released outside the system. In this way, when handling radioactive materials, necessary work is carried out while ensuring sufficient safety.

To carry out work rationally while ensuring safety under these conditions, it is necessary to create work processes and implement work equipment that allow work to be carried out rationally while monitoring radiation doses at the work site and managing the upper dose limits that must be observed for work safety.

When formulating work plans for the safe handling of radioactive materials, work is planned based on prior assessments using set values with sufficient margin to ensure compliance with the upper dose limits for the work. However, the set values were not updated or predicted using actual dose measurements during work, and the work plans were not updated accordingly. As a result, in cases where the actual dose measurements were low compared to the set values and sufficient safety could be guaranteed even if the amount of work was changed, the amount of work involving handling the work objects was limited, and the impact of variations in the radioactivity concentration of the work objects could not be taken into account in the work plans.

Patent Document 1 describes how the air dose rate measured by a radiation monitor is sent to a signal processing device, which then calculates the dust radioactivity concentration using a predetermined correlation equation. However, this method makes no mention of the device configuration or work process required to update, estimate, or predict set values using actual dose measurements during work, or to update work plans accordingly, making it difficult to update planned work with set values that have sufficient margins.

Patent Document 2 also describes a system that uses local dose rate measurement devices to measure the dose rate of one or more high-dose-rate items, a dose rate distribution device that uses the dose rates obtained by these local dose rate measurement devices to estimate the dose rate at a dose rate monitoring point, and updates a work plan so that the allowable dose rate is not exceeded. However, because the local dose rate measurement device uses a local radiation detector placed on or near a high-dose-rate item, it is difficult, due to the device configuration, to place the work object in a specific area, continuously monitor changes in the dose rate there, and perform updates and predictions, as well as updating the work plan accordingly.

The object of the present invention is to provide a dose estimation device, work plan update system, dose estimation method, and work plan update method that enable radioactive material handling work to be carried out more rationally than conventional methods while ensuring work safety.

The present invention includes multiple means for solving the above-mentioned problems, and examples thereof include a remote-operated device for handling work objects in a first area, a remote-operated dosimeter for measuring the dose rate around the remote-operated device, a dose distribution database for recording the dose distribution in the first area, a first radioactivity concentration estimation device for calculating a first radioactivity concentration from the first area dose rate measured by the remote-operated dosimeter and the dose distribution recorded in the dose distribution database, a receiving device for receiving the work objects transported in a second area different from the first area, a receiving device dosimeter for measuring the dose rate around the receiving device, and a radioactivity concentration estimation device for calculating a first radioactivity concentration from the first area dose rate measured by the remote-operated dosimeter and the dose distribution recorded in the dose distribution database. The system comprises a second radioactivity concentration estimation device that calculates a second radioactivity concentration from a second area dose rate measured by a dosimeter for a collection device; an update coefficient calculation device that calculates an update coefficient for approximating the first radioactivity concentration to the second radioactivity concentration; a third radioactivity concentration estimation device that calculates a third radioactivity concentration in the first area associated with the transportation of the work object from the first area dose rate, the dose distribution recorded in the dose distribution database, and the update coefficient calculated by the update coefficient calculation device; and a monitoring dose estimation device that estimates a dose rate at a monitoring position from each of the first radioactivity concentration, the second radioactivity concentration, and the third radioactivity concentration.

The present invention makes it possible to carry out radioactive material handling work more efficiently than conventional methods while ensuring operational safety. Other issues, configurations, and advantages will become clearer in the following description of the examples.

1 is a diagram showing the configuration of a dose estimation apparatus according to a first embodiment of the present invention; FIG. 4 is a diagram showing profiles and items of a dose distribution database according to the first embodiment. 4A and 4B are diagrams showing dose distribution profile data and dose rate measurement data in Example 1. FIG. 2 is a diagram showing a dose estimation method according to the first embodiment. FIG. 10 is a diagram showing the configuration of a work plan updating system according to a second embodiment. FIG. 10 is a diagram showing a work plan updating method according to a second embodiment. FIG. 11 is a diagram showing a part of the configuration of a dose estimation apparatus in a first area according to a third embodiment. FIG. 11 is a diagram showing another part of the configuration of the dose estimation apparatus in the first area according to the third embodiment. 10A and 10B are diagrams showing dose distribution profile data and dose rate measurement data in Example 3. FIG. 10 is a diagram showing the configuration of a dose estimation apparatus according to a fourth embodiment. FIG. 10 is a diagram showing time series data of the dosimeter of Example 4. FIG. 10 is a diagram showing time series data of the radioactivity concentration estimated from the measurement data of the first area and the monitoring dose estimated from the radioactivity concentration in Example 4. FIG. 10 is a diagram showing the configuration of a dose estimation apparatus according to a fifth embodiment. FIG. 10 shows energy analysis data of Example 5. FIG. 10 is a diagram showing dose distribution profile data of Example 5.

This invention was developed based on new findings gained through extensive research in order to rationally carry out work involving the handling of radioactive materials while adhering to the maximum dose limits that must be observed for work safety.

Below, examples of the dose estimation device and work plan updating system, as well as the dose estimation method and work plan updating method for safely handling radioactive materials of the present invention, are described with reference to the drawings. Note that in the drawings used in this specification, identical or corresponding components are designated by the same or similar reference numerals, and repeated explanations of these components may be omitted.

Example 1
A dose estimation apparatus and a dose estimation method according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG.

First, the overall configuration of the dose estimation device will be explained using Figure 1. Figure 1 shows a configuration diagram of the dose estimation device.

The dose estimation device 100 of Example 1 shown in Figure 1 is a device that is preferably used when formulating a work plan for work involving the safe handling of a work object 112 that is a radioactive material, and is composed of a remote-operated device 101, a remote-operated dosimeter 102, a receiving device 104, a dosimeter for the receiving device 105, a dose distribution database 106, a first radioactivity concentration estimation device 107, a second radioactivity concentration estimation device 108, an update coefficient calculation device 109, a third radioactivity concentration estimation device 110, and a monitoring dose estimation device 111, etc.

In the first area 113 where the work object 112 is located, a remote-operated device 101 that handles the work object 112 in this first area 113 and a remote-operated dosimeter 102 that measures the dose rate around the remote-operated device 101 are placed.

In addition, a second area 114, different from the first area 113, is provided with a receiving device 104 that receives the work object 112 transported along the transport path 103 and a receiving device dosimeter 105 that measures the dose rate around the receiving device 104.

The first area 113 and the second area 114 are connected by a transport route 103.

The first area 113 and the second area 114 are environments where worker entry is restricted and controlled due to safety concerns regarding temperature, oxygen, radiation levels, dust, and darkness.

The dose distribution database 106, first radioactivity concentration estimation device 107, second radioactivity concentration estimation device 108, update coefficient calculation device 109, third radioactivity concentration estimation device 110, and monitoring dose estimation device 111 are preferably located in a separate area that is different from the first area 113 and second area 114 and that workers can access relatively easily, allowing various operational management tasks to be carried out.

The work object 112 may be in various forms, such as solid, sand, or liquid, and may change shape depending on the work being performed. Therefore, handling the work object 112 with the remote-operated work device 101 may cause the shape or radioactivity concentration to change.

A portion of the work object 112 collected by the remote-operated device 101 is transported to the receiving device 104 via the transport path 103. There are no particular restrictions on the transport path 103 as long as it can transport the work object 112; if it is solid, it can be transported using a remote-operated device (not shown for convenience of illustration), or placed in a container and transported using a conveyor, etc.; if it is liquid, it can be transported using a pump and hose, etc., and a method will be used depending on the form of the work object 112 and the work efficiency.

The remote-operation dosimeter 102 continuously monitors changes in the dose rate in the first area 113, which is the work environment in which the remote-operation device 101 works. Similarly, the receiving device dosimeter 105 is placed near the receiving device 104 and continuously monitors changes in the dose rate in the second area 114 and near the receiving device 104.

Typical dosimeters that make up the remote work dosimeter 102 and the receiving device dosimeter 105 include semiconductor, scintillation, optical fiber, and gas types.

Examples of semiconductors include silicon, silicon carbide (SiC), diamond, germanium (Ge), GaAs, CdTe, CZT, TlBr, and other compound semiconductors. Examples of scintillation systems include various phosphors such as NaI, CsI, _LaBr3 , _LaCl3 , SrI, BGO, and GSO. Examples of optical fiber systems include YAG, YAP, and systems in which the phosphor used in the scintillation system described above is attached to the tip of an optical fiber, and systems in which the optical fiber itself is used as a phosphor to analyze dose and position information. Examples of gas systems include ionization chambers, GM counters, and proportional counters.

The dose measured here is the dose caused primarily by gamma rays emitted from radioactive materials contained in the work object 112, and will be described in subsequent examples as dose measurement results using gamma rays. However, this is not limited to gamma rays, and neutrons, which have relatively high penetrating properties, can also be measured, and other types of radiation can also be measured.

When measuring neutrons, detectors that measure thermal neutrons or epithermal neutrons, or detectors that measure fast neutrons, or detectors that measure both, are used. Typical types of thermal neutron detectors include gas detectors, scintillation detectors, and semiconductor detectors. These detectors use thermal neutron-sensitive materials such as lithium, boron, gadolinium, cadmium, uranium, and plutonium. Gas detectors that use He-3 proportional counters, _BF3 proportional counters, B-10 coated proportional counters, and fission counters. Scintillation detectors are equipped with scintillators containing elements with large cross sections for thermal neutrons, such as lithium-6, boron-10, and gadolinium. Types of scintillators include, for example, LiI:Eu, ZnS:Ag, plastic scintillators containing boron-10, glass scintillators containing lithium-6 or boron-10, LiCaAlF ₆ , Gd ₃ Al ₂ Ga ₃ O ₁₂ , Gd ₂ SiO ₅ :Ce, Cs ₂ LiLaBr ₆ :Ce, Cs ₂ LiYCl ₆ :Ce, Cs ₂ LiLaCl ₆ :Ce, Cs ₂ LiLaBr ₆ - _x Cl _x :Ce, and Cs ₂ LiYBr ₆ :Ce.

There is also a method of coating the surface of the scintillator with an element that is sensitive to thermal neutrons. In this case, not only the scintillators mentioned above, but also all scintillators used as radiation detectors, such as _LaBr3 , _CsBr3 , LYSO, LSO, GAGG, CsI, NaI, BGO, GPS, La-GPS, LuAG, SrI, and plastic scintillators, can be used as neutron detectors.

Similarly, semiconductor detectors are equipped with semiconductors containing elements with a large cross section for thermal neutrons, such as lithium-6, boron-10, gadolinium, etc., and examples of such semiconductors include CdTe and CdZnTe. There is also a method of coating the surface of a semiconductor with an element that is sensitive to thermal neutrons, in which case semiconductor detectors such as silicon, germanium, diamond, silicon carbide, and semiconductor detectors with a Perovskite structure, such as _CsPbCl3 , _CsPbBr3 , and _LiTaO3, can be used in addition to CdTe and CdZnTe.

Epithermal neutron detectors include gas detectors called recoil proton counters, which use hydrogen or methane gas as the sensitive element and measure the energy transferred by recoil protons resulting from the reaction between neutrons and hydrogen.

Threshold detectors are used to detect fast neutrons. One of the most commonly used types is the fission counter, which uses uranium-234, uranium-236, uranium-238, neptunium-237, or thorium-232 as the neutron-sensitive element. Organic scintillators such as anthracene and stilbene are also used. It is also possible to use detectors that measure fast neutrons using the scintillation light emitted from pressurized helium-4 gas.

Figure 2 shows the profile and items of the dose distribution database. The dose distribution database 106 shown in Figure 2 is a recording medium that records the dose distribution in the first area 113, and is created by analyzing the dose distribution in the first area 113 in advance and storing the analysis results in a database.

The database requires that a dose distribution profile calculated from two or more shape profiles, two or more material profiles, or two or more radioactivity concentration profiles, or a combination of any of these, be recorded.

The shape profile of the work object 112 is formed from a polygonal model, an elliptical model, a circular model, or a model that combines these. The material profile is formed from the composition, density, and porosity. The radioactivity concentration profile shows the radioactivity concentration profile inside the work object 112, and is formed from a uniform model, an eccentric 1 model (high outside, low inside), an eccentric 2 model (low outside, high inside), a layered model, or a model that combines these.

The first radioactivity concentration estimation device 107 calculates a first radioactivity concentration from the first area dose rate measured by the remote operation dosimeter 102 and the dose distribution recorded in the dose distribution database 106. Dose distribution profile data and dose rate measurement data are shown in Fig. 3. The first radioactivity concentration estimation device 107 preferably executes the step of calculating a first radioactivity concentration from a first measured dose rate measured at time _t0 in the first area 113 where the work object 112 is handled and a pre-recorded dose distribution in the first area 113.

The first radioactivity concentration estimation device 107 selects the most appropriate dose distribution profile by comparing the correlation between the dose rate measurement data 118 and the dose distribution profiles 115, 116, and 117, as shown in Figure 3.

In FIG. 3 , correlations can be compared using various methods, including maximum likelihood estimation (e.g., least squares method), maximum a posteriori probability estimation, Bayesian estimation, and machine learning using various techniques including deep learning, or by limiting the shape profile using camera image data mounted on the remote operation device 101, or by combining these methods. Here, as an example, dose rate measurement data 118 at three points and dose distribution profiles 115, 116, and 117 at three points are used, but other points are also acceptable. A dose distribution profile can be selected by acquiring dose rate measurement data at one point and limiting the shape profile using camera image data. Once the dose distribution profile is selected, the first radioactivity concentration is estimated according to equation (1).
S _1n = PF _1a (D _1n (x)) (1)

In equation (1), S _1n is the nth radioactivity concentration (Bq/g) in the first area 113, PF _1a is the ath dose distribution profile in the first area 113, and D _n (x) is the nth dose rate measurement data (Gy/h) at a distance x from the work object.

The second radioactivity concentration estimation device 108 is a part that calculates a second radioactivity concentration from the second area dose rate measured by the receiving device dosimeter 105, and because the positional relationship between the receiving device 104 and the receiving device dosimeter 105 is fixed, it estimates the radioactivity concentration of the work object 112 received by the receiving device 104 from the dose rate measurement data by the receiving device _dosimeter 105. This second radioactivity concentration estimation device 108 preferably executes the step of calculating the second radioactivity concentration from the second measured dose rate measured in the second area 114 when the work object 112 reaches the second area 114 different from the first area 113 at time _t1 , which is after time t0.

The second radioactivity concentration estimation device 108 estimates the second radioactivity concentration according to the following equation (2).
S _2n = PF ₂ (D _2n ) (2)

In equation (2), S _2n is the nth radioactivity concentration (Bq/g) of the second area 114, PF ₂ is the dose distribution profile of the second area 114, and D _2n is the nth dose rate measurement data (Gy/h) of the second area.

The update coefficient calculation device 109 is a part that calculates an update coefficient for approximating the first radioactivity concentration determined by the first radioactivity concentration estimation device 107 to the second radioactivity concentration determined by the second radioactivity concentration estimation device 108, and calculates the update coefficient using, for example, the following formula (3). The update coefficient is calculated by using machine learning using various techniques including maximum likelihood estimation typified by the least squares method, maximum a posteriori probability estimation, Bayesian estimation, and deep learning, in combination with a database of data calculated in the past from the (n+1)th time onwards and analysis results of dose distribution, and formula (3). The update coefficient calculation device 109 preferably executes the step of calculating an update coefficient for approximating the first radioactivity concentration to the second radioactivity concentration.
ΔS _n =-(S _1n - S _2n )/S _2n (3)

In equation (3), ΔS _n is the n-th update coefficient.

The third radioactivity concentration estimation device 110 is a part that calculates a third radioactivity concentration in the first area 113 associated with the transportation of the work object 112 from the first area dose rate, the dose distribution recorded in the dose distribution database 106, and the update coefficient calculated by the update coefficient calculation device 109, and estimates the third radioactivity concentration using the following formula (4): This third radioactivity concentration estimation device 110 preferably executes the step of calculating the third radioactivity concentration based on the third measured dose rate measured in the first area 113 at time _t2 , which is after time _t0, the dose distribution in the first area 113 that has been recorded in advance, and the update coefficient.
S _1(n+1) =PF _1a (D _1(n+1) (x))/ΔS _n (4)

In equation (4), S _1n is the (n+1)th radioactivity concentration (Bq/g) in the first area 113, PF _1a is the ath dose distribution profile in the first area 113, and D _n (x) is the nth dose rate measurement data (Gy/h) at a distance x from the work object.

The monitoring dose estimation device 111 is a part that uses any one or more of formulas (5) to (7) to estimate a dose rate at a monitoring position that is made up of various positions, such as a position where a monitoring post or the like is installed in a work area including the second area 114, from each of the first radioactivity concentration, the second radioactivity concentration, and the third radioactivity concentration. This monitoring dose estimation device 111 preferably executes a monitoring dose estimation step that estimates a dose rate at a monitoring position from each of the first radioactivity concentration, the second radioactivity concentration, and the third radioactivity concentration.
D _n =S _1n ×W _n ×C (5)

In equation (5), D _n is the estimated monitoring dose (Gy/h) at the nth monitoring position, W _n is the received dose (g) at the nth receiving device, and C is the monitoring dose conversion coefficient.
D _n =S _2n ×W _n ×C (6)

In equation (6), D _n is the estimated monitoring dose (Gy/h) at the nth monitoring position, W _n is the received dose (g) at the nth receiving device, and C is the monitoring dose conversion coefficient.
D _n =S _3n ×W _n ×C (7)

In equation (7), D _n is the estimated monitoring dose (Gy/h) at the nth monitoring position, W _n is the received dose (g) at the nth receiving device, and C is the monitoring dose conversion coefficient.

Here, the monitoring dose at the monitoring location is calculated by multiplying each radioactivity concentration, the amount received at the receiving device 104, and the monitoring dose conversion coefficient. The received amount is calculated using the weight scale of the receiving device 104, or, if it is liquid, by visually inspecting the internal volume of the receiving device 104. The monitoring dose conversion coefficient is a calculated value calculated in advance using an analysis system that simulates the positional relationship between the receiving device 104 and the monitoring location, shielding such as structures, and spatial conditions.

The dose distribution database 106, first radioactivity concentration estimation device 107, second radioactivity concentration estimation device 108, update coefficient calculation device 109, third radioactivity concentration estimation device 110, and monitoring dose estimation device 111 described above can be realized by a PC (Personal Computer) equipped with hardware such as a calculation device such as a CPU, a main storage device such as semiconductor memory and an auxiliary storage device such as a hard disk, input devices such as a keyboard and USB port, and an output device consisting of a monitor, and the operation of each device and the various calculation processes described below are controlled based on various programs.

The programs can be stored in an internal memory unit, an external recording medium, a data server (all not shown), etc., and can be read and executed by the CPU. The control processes can be integrated into a single program, or each can be separated into multiple programs, or a combination of these. Some or all of the programs can be implemented using dedicated hardware, or can be modularized. Furthermore, the various programs can be installed from a program distribution server, internal storage medium, or external storage medium.

The work performed on the work object 112 envisioned by this invention is carried out continuously or intermittently. Therefore, it is preferable to use the dose estimation device 100 described above to estimate the radiation concentration in each area as the work progresses, such as the fourth radiation concentration, the fifth radiation concentration, etc., and to calculate update coefficients continuously or at predetermined intervals, and to perform the process of estimating the dose rate at the monitoring position continuously or at predetermined intervals.

Next, the flow of the dose estimation method of the present invention will be explained using Figure 4. Figure 4 shows the dose estimation method.

As shown in Figure 4, first, the remote operation dosimeter 102 measures the dose rate D _1n (x) in the first area 113 (S1001), and the first radioactivity concentration estimation device 107 compares the dose rate D _1n (x) with the dose distribution PF _1a to estimate the first radioactivity concentration S _1n (S1002).

Next, the monitoring dose estimation device 111 sets a planned value of the received dose _Wn of the receiving device 104 at t=t1 (S1003), and estimates the monitored dose _Dn at the monitoring position at t=t1 (S1004).

Next, the remote-operated work device 101 begins removing the work object 112 (S1005).

Next, the dosimeter 105 for the receiving device measures the dose rate D _2n in the second area 114 (S1006), and the second radioactivity concentration estimation device 108 compares the dose rate D _2n with the dose distribution PF ₂ to estimate the second radioactivity concentration S _2n (S1007).

Next, the monitoring dose estimation device 111 estimates the monitoring dose D _n at the monitoring position from the measured value or evaluated value of the received dose W _n of the receiving device 104 (S1008).

Next, preferably the worker, manager, or work plan update device 119 (see Figure 5) determines whether removal of the work object 112 has been completed (S1009).

If it has been completed, the process ends; if it has not been completed, the process proceeds to step S1010, where the update coefficient calculation unit 109 calculates the update coefficient ΔS _n (S1010).

Next, the remote-operated dosimeter 102 measures the dose rate D _1(n+1) (x) in the first area 113 (S1011).

Next, the third radioactivity concentration estimation device 110 compares the dose rate D _1(n+1) (x), the dose distribution PF _1a , and the update coefficient ΔS _n to estimate the third radioactivity concentration S _1(n+1) (S1012).

Next, a planned value of the receiving amount W _n+1 of the receiving device 104 is set (S1013).

Next, the monitoring dose estimation device 111 estimates a monitoring dose D _n+1 at the monitoring position (S1014), after which the process returns to S1005.

Next, we will explain the effects of this embodiment.

The dose estimation device 100 of the first embodiment of the present invention described above includes a remote-operated device 101 that handles a work object 112 in a first area 113, a remote-operated dosimeter 102 that measures the dose rate around the remote-operated device 101, a dose distribution database 106 that records the dose distribution in the first area 113, a first radioactivity concentration estimation device 107 that calculates a first radioactivity concentration from the first area dose rate measured by the remote-operated dosimeter 102 and the dose distribution recorded in the dose distribution database 106, a receiving device 104 that receives the work object 112 transported in a second area 114 different from the first area 113, and a receiving device dose meter 106 that measures the dose rate around the receiving device 104. the receiving device dosimeter 105; a second radioactivity concentration estimation device 108 that calculates a second radioactivity concentration from the second area dose rate measured by the receiving device dosimeter 105; an update coefficient calculation device 109 that calculates an update coefficient for approximating the first radioactivity concentration to the second radioactivity concentration; a third radioactivity concentration estimation device 110 that calculates a third radioactivity concentration in the first area 113 associated with the transportation of the work object 112 from the first area dose rate, the dose distribution recorded in the dose distribution database 106, and the update coefficient calculated by the update coefficient calculation device 109; and a monitoring dose estimation device 111 that estimates the dose rate at the monitoring position from each of the first radioactivity concentration, the second radioactivity concentration, and the third radioactivity concentration.

This makes it possible to estimate the dose required to rationally carry out work involving the handling of radioactive materials while ensuring work safety, thereby enabling the updating and prediction of set values using actual dose measurements during work, as well as the associated updating of work plans and monitoring and control of work volume.

In addition, the dose distribution database further records a dose distribution profile calculated from two or more shape profiles, two or more material profiles, two or more radioactivity concentration profiles, or a combination of any of these, making it possible to calculate the first radioactivity concentration with high accuracy.

Furthermore, by calculating update coefficients continuously or at predetermined intervals and estimating the dose rate at the monitoring location, it is possible to revise work plans in response to changes in the work environment over time.

Example 2
A work plan updating system according to a second embodiment of the present invention will be described with reference to Figures 5 and 6. Figure 5 is a diagram showing the work plan updating system according to the second embodiment, and Figure 6 is a diagram showing a work plan updating method.

Example 2 relates to a specific example of an apparatus and method for updating a work plan based on updating or estimating set values using actual dose measurements during work.

The work plan update system 140 of this embodiment shown in Figure 5 is composed of a work plan update device 119, a work process database 120, a worker database 121, a work crew organization database 122, a work equipment database 123, a work monitoring equipment database 124, a work environment database 125, and a work plan display device 126, in addition to the dose estimation device 100 of embodiment 1 shown in Figure 1.

Of these, the work process database 120, work personnel database 121, work crew organization database 122, work equipment database 123, work monitoring equipment database 124, and work environment database 125 are preferably configured on a data server or the like, but there are no particular limitations.

The work plan update system 140 transmits dose rate data at the monitoring position from the dose estimation device 100 to the work plan update device 119.

The work process database 120 stores work processes and work plans related to the handling of the work object 112, and transmits this data to the work plan update device 119.

The worker database 121 stores data on workers who are involved in handling the work object 112. For example, labor, safety management, and technical data such as the worker's years of experience, skill data, health management time, and cumulative radiation exposure dose including other work are registered. This worker data is transmitted to the work plan update device 119.

The work crew organization database 122 stores worker team organization profiles constructed according to the work process, work content, and worker data, as well as team organization data incorporating the workers. This team organization data is transmitted to the work plan update device 119.

The work equipment database 123 stores data on the equipment, facilities, and facilities used to handle the work object 112. This work equipment data is transmitted to the work plan update device 119.

The work monitoring equipment database 124 stores data related to equipment that monitors the handling of the work object 112. This includes not only the equipment, facilities, and equipment used to handle the work object 112, but also monitoring equipment used to monitor other work. For example, area radiation monitors and dust monitors in the building where the work is carried out, and monitoring posts that monitor radiation throughout the radiation controlled area. This work monitoring equipment data is transmitted to the work plan update device 119.

The work environment database 125 stores environmental data for the first area 113, second area 114, and transportation route 103. For example, this includes the dimensions of the area, dose rates, and the location of structures and obstructions. This work environment data is transmitted to the work plan update device 119.

The work plan update device 119 is the part that updates the work plan for handling the work object 112 based on the input estimated dose rate at the monitoring location. It is a device that performs work plan updates using mathematical optimization models, machine learning functions, or human adjustments and decision-making, and updates the work period and its context, updates the associated work content, adjusts the workers involved in the work and their team composition, and adjusts the equipment, facilities, and facilities to be used. The results of this update are visualized on the work plan display device 126. This work plan update device 119 is preferably the entity that executes the process of updating the work plan for handling the work object 112 based on the estimated dose rate at the monitoring location and the upper dose rate limit that must be observed.

The updated new work plan visualized on the work plan display device 126 is presented to the worker, and work on the work object 112 is carried out based on the new work plan.

Figure 6 shows the work plan update method. This is used as a subroutine in addition to the dose estimation method shown in Figure 4.

As shown in FIG. 6, when a monitoring dose is estimated, for example, in step S1004, step S1008, or step S1014, data including each database is aggregated in the work plan update device 119 (S2001).

Next, the work plan is updated by the work plan update device 119 (S2002), and the work plan is visualized by the work plan display device 126 (S2003).

Other configurations and operations are substantially the same as those of the dose estimation device and dose estimation method of Example 1 described above, and details are omitted.

The work plan updating system and work plan updating method of Example 2 of the present invention also have the dose estimation device and dose estimation method of Example 1 described above, and therefore can achieve substantially the same effects.

The system also includes a work plan update device 119 that updates the work plan for handling the work object 112 based on the estimated dose rate at the monitoring position, and includes a process for updating the work plan for handling the work object 112 based on the estimated dose rate at the monitoring position and the upper dose rate limit to be observed, and a process for presenting the updated new work plan to the worker and performing work on the work object 112 based on the new work plan. This makes it possible not only to update and predict setting values using actual dose measurements during work, but also to update work plans and monitor and control the workload based on the processes, personnel, and various data associated with the work.

Note that, although the dose estimation device 100 described in Example 1 is used as the dose estimation device provided in the work plan update system 140, any of the dose estimation device of Example 3, the dose estimation device 150 of Example 4, and the dose estimation device 200 of Example 5 described below can be used instead of the dose estimation device 100.

Example 3
A dose estimation device and a dose estimation method according to a third embodiment of the present invention will be described with reference to Fig. 7 to Fig. 9. Fig. 7 and Fig. 8 are diagrams showing a part of the configuration of the dose estimation device in the first area according to the third embodiment, and Fig. 9 is a diagram showing dose distribution profile data and dose rate measurement data.

Example 3 relates to an apparatus and method for estimating radioactivity concentrations using multiple dosimeters and a remote-operated device.

As shown in FIG. 7, the first area 113 is configured with multiple remote-operated devices 101a, 101b and remote-operated dosimeters 102a, 102b mounted on these remote-operated devices. Here, as an example, two sets of remote-operated devices 101a, 101b and remote-operated dosimeters 102a, 102b are shown, but three or more sets can be used.

As shown in FIG. 8, another possible configuration is one in which multiple remote-operated dosimeters 102c are mounted on one remote-operated device 101. Conversely, it is also possible to configure multiple remote-operated devices with one remote-operated dosimeter.

In these cases, the first area dose rate is measured using a combination of multiple remote-operated devices 101a, 101b and/or remote-operated dosimeters 102a, 102b, 102c.

Figure 9 shows dose distribution profile data and dose rate measurement data. Here, dose rate measurement data 118a, 118b, 118c, and 118d are shown as an example. These dose rate measurement data 118 are measured using the device configurations shown in Figures 7 and 8, and are compared with the dose distribution profile.

Other configurations and operations are substantially the same as those of the dose estimation device and dose estimation method of Example 1 described above, and details are omitted.

The dose estimation device and dose estimation method of Example 3 of the present invention also provide substantially the same effects as those of the dose estimation device and dose estimation method of Example 1 described above.

Furthermore, by configuring at least one of the remote-operated devices 101a, 101b and remote-operated dosimeters 102a, 102b, and 102c in a multiple-unit configuration, and measuring the first area dose rate using a combination of multiple remote-operated devices 101a, 101b and/or remote-operated dosimeters 102a, 102b, and 102c, dose rate measurement data can be measured quickly, making it possible to quickly estimate radioactivity concentration and monitoring dose. Furthermore, since the number of measurement data and available measurement points increases, statistical accuracy can be improved, and further improvements in the estimation accuracy of radioactivity concentration and monitoring dose can be expected.

Example 4
A dose estimation device and a dose estimation method according to a fourth embodiment of the present invention will be described with reference to Fig. 10 to Fig. 12. Fig. 10 is a diagram showing the configuration of the dose estimation device according to the fourth embodiment, Fig. 11 is a diagram showing time-series data of a dosimeter, and Fig. 12 is a diagram showing time-series data of the radioactivity concentration estimated from the measurement data of the first area and the monitoring dose estimated from the radioactivity concentration.

Example 4 relates to a dose estimation device and method that incorporates the transportation route time when the transportation time from the first area to the second area is significant.

The dose estimation device 150 of this embodiment shown in Figure 10 further includes a transportation time calculation device 155 that calculates the transportation time along the transportation route for transporting the work object 112 from the first area 113 to the second area 114, and the monitoring dose estimation device 157 also uses the transportation time calculated by the transportation time calculation device 155 to estimate the dose rate at the monitoring position.

For example, as shown in FIG. 10, when a work object 112 is transported from a first area 113 to a second area 114 via a transport route 103, and the first area 113 and the second area 114 are separated by a certain distance, it can be determined that there is a transport time ΔT _n that is significant for the work.

Figure 11 shows the time series data of the dosimeter. Here, time series data 127 is the radioactivity concentration estimated based on the remote-operation dosimeter 102, and time series data 128 is the radioactivity concentration estimated based on the receiving device dosimeter 105. The vertical axis represents the measured dose rate, but the magnitude relationship between the values of the time series data is ignored here. Also, assume that handling work started at time _T0 .

11 , from time T1 during the work, an increase in the estimated radioactivity concentration of the work object 112 is observed from the time series data 127. In this case, the work object 112 arrives at the second area at T = T ₁ + ΔT _n , and a change in response can be observed from that point.

If there is a significant transportation time _ΔTn for the work, it is necessary to calculate the monitoring dose taking that time difference into account. Figure 12 shows the time series data of the radioactivity concentration estimated from the measurement data in the first area and the monitoring dose estimated from that radioactivity concentration.

As shown in FIG. 12, when a radioactivity concentration 129 is estimated from the measurement data of the first area and a monitoring dose 130 is calculated from the radioactivity concentration, equation (8) is used to take into account the transportation time ΔT _n .
D _n (t)=S _1n (t-ΔT _n )×W _n (t)×C (8)

In equation (8), D _n is the estimated monitoring dose (Gy/h) at the nth monitoring position, W _n is the amount (g) received by the receiving device 104 at the nth time, and C is the monitoring dose conversion coefficient. In equation (8), to estimate the monitoring dose at time t, the radioactivity concentration at time t-ΔT _n and the amount W _n (t) received by the receiving device 104 at time t are used.

Other configurations and operations are substantially the same as those of the dose estimation device and dose estimation method of Example 1 described above, and details are omitted.

The dose estimation device and dose estimation method of Example 4 of the present invention also provide substantially the same effects as those of the dose estimation device and dose estimation method of Example 1 described above.

The system also includes a transportation time calculation device 155 that calculates the transportation time along the transportation route for transporting the work object 112 from the first area 113 to the second area 114. The monitoring dose estimation device 157 also uses the transportation time to estimate the dose rate at the monitoring position, making it possible to predict setting values using actual dose measurements during work, and to update work plans and monitor and control the workload accordingly.

Example 5
A dose estimation apparatus and a dose estimation method according to a fifth embodiment of the present invention will be described with reference to Fig. 13 to Fig. 15. Fig. 13 is a diagram showing the configuration of the dose estimation apparatus according to the fifth embodiment, Fig. 14 is a diagram showing energy analysis data, and Fig. 15 is a diagram showing dose distribution profile data.

Example 5 relates to an apparatus and method for estimating radioactivity concentration using radiation energy analysis.

In the dose estimation device 200 of this embodiment shown in FIG. 13, the remote-operated dosimeter 131 with energy analysis function and the dosimeter 133 with energy analysis function for the receiving device have a radiation energy analysis function, and the dose distribution database 132 has radiation energy information. Note that it is sufficient that at least one of the remote-operated dosimeter 131 with energy analysis function and the dosimeter 133 with energy analysis function has the energy analysis function.

Figure 14 shows energy analysis data. Here, energy spectrum 134 is shown as an example. As shown in Figure 14, to use energy analysis data, for example, a region of energy spectrum 134 where radiation energy is highly imparted is extracted as region of interest 135, and only the measurement values within region of interest 135 are handled.

Figure 15 shows dose distribution profile data using energy analysis. As shown in Figure 15, when using the measured value of the region of interest 135 in Figure 14, for example, for the energy spectrum 134 compared with the dose rate measured by the remote-operated dosimeter 102, dose distribution profile 136, out of dose distribution profiles 136 and 137, will be compared with the measured value.

As another example, when observing and comparing neutrons (thermal neutrons) in the 0.025 eV energy range of the neutron energy range, they can be compared with the dose distribution profile 136.

Other configurations and operations are substantially the same as those of the dose estimation device and dose estimation method of Example 1 described above, and details are omitted.

The dose estimation device and dose estimation method of Example 5 of the present invention also provide substantially the same effects as those of the dose estimation device and dose estimation method of Example 1 described above.

In addition, at least one of the remote work dosimeter 131 with energy analysis function and the receiving device dosimeter 133 with energy analysis function is equipped with a radiation energy analysis function, and the dose distribution database 132 is equipped with radiation energy information. By utilizing not only dose rate measurement data but also energy information, it is possible to select a dose distribution profile that matches the energy, which is expected to improve the estimation accuracy of radioactivity concentration and monitoring dose.

<Others>
It should be noted that the present invention is not limited to the above-described embodiment, and includes various modifications. The above-described embodiment has been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to an embodiment having all of the described configurations.

It is also possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of one embodiment to the configuration of another embodiment. It is also possible to add, delete, or replace part of the configuration of each embodiment with the configuration of another embodiment.

100, 150, 200... Dose estimation device 101, 101a, 101b... Remote-operated device 102, 102a, 102b, 102c... Remote-operated dosimeter 103... Transportation route 104... Receiving device 105... Receiving device dosimeter 106... Dose distribution database 107... First radioactivity concentration estimation device 108... Second radioactivity concentration estimation device 109... Update coefficient calculation device 110... Third radioactivity concentration estimation device 111, 157... Monitoring dose estimation device 112... Work object 113... First area 114... Second area 115, 116, 117, 136, 137... Dose distribution profile 118, 118a, 118b, 118c, 118d... Dose rate measurement data 119... Work Plan update device 120...work process database 121...work personnel database 122...work crew organization database 123...work equipment database 124...work monitoring equipment database 125...work environment database 126...work plan display device 127, 128...time series data 129...radioactivity concentration estimated from measurement data of first area 130...monitored dose 131...remote work dosimeter with energy analysis function 132...dose distribution database with energy analysis data 133...receiving device dosimeter with energy analysis function 134...energy spectrum 135...area of interest 140...work plan update system 155...transportation time calculation device

Claims (9)

a remote-controlled work device that handles a work object in a first area;
a remote-operation dosimeter that measures a dose rate around the remote-operation device;
a dose distribution database that records a dose distribution in the first area;
a first radioactivity concentration estimation device that calculates a first radioactivity concentration from a first area dose rate measured by the remote-operation dosimeter and the dose distribution recorded in the dose distribution database;
a receiving device that receives the work object transported in a second area different from the first area;
a receiving device dosimeter for measuring a dose rate around the receiving device;
a second radioactivity concentration estimation device that calculates a second radioactivity concentration from the second area dose rate measured by the receiving device dosimeter;
an update coefficient calculation device that calculates an update coefficient for approximating the first radioactivity concentration to the second radioactivity concentration;
a third radioactivity concentration estimation device that calculates a third radioactivity concentration in the first area associated with transportation of the work object based on the first area dose rate, the dose distribution recorded in the dose distribution database, and the update coefficient calculated by the update coefficient calculation device; and
a monitoring dose estimation device that estimates a dose rate at a monitoring position from each of the first radioactivity concentration, the second radioactivity concentration, and the third radioactivity concentration. 2. The dose estimation apparatus according to claim 1,
The dose distribution database further records a dose distribution profile calculated from any one of two or more shape profiles, two or more material profiles, and two or more radioactivity concentration profiles, or a combination of any of these. 2. The dose estimation apparatus according to claim 1,
a dose estimation device including a plurality of remote-operated devices and/or a plurality of remote-operated dosimeters, and measuring the first area dose rate by combining a plurality of the remote-operated devices and/or the remote-operated dosimeters. 2. The dose estimation apparatus according to claim 1,
a transportation time calculation device that calculates a transportation time along a transportation route for transporting the work object from the first area to the second area;
The monitoring dose estimation device estimates a dose rate at the monitoring position by also utilizing the transportation time. 2. The dose estimation apparatus according to claim 1,
At least one of the remote work dosimeter and the receiving device dosimeter has a radiation energy analysis function;
The dose distribution database includes radiation energy information. A dose estimation device according to any one of claims 1 to 5;
a work plan updating device that updates a work plan for handling the work object based on the dose rate at the monitoring position estimated by the dose estimation device. A step of determining a first radioactivity concentration from a first measured dose rate measured at time _t0 in a first area where the work object is handled and a pre-recorded dose distribution in the first area;
determining a second radioactivity concentration from a second measured dose rate measured in a second area different from the first area when the work object reaches the second area at time _t1 after time _t0 ;
calculating an update coefficient for approximating the first radioactivity concentration to the second radioactivity concentration;
determining a third radioactivity concentration based on a third measured dose rate measured in the first area at time _t2 after time _t0 , a pre-recorded dose distribution in the first area, and the update coefficient;
a monitoring dose estimation step of estimating a dose rate at a monitoring position from each of the first radioactivity concentration, the second radioactivity concentration, and the third radioactivity concentration. 8. The dose estimation method according to claim 7,
A dose estimation method for estimating a dose rate at the monitoring position by calculating the update coefficient continuously or at predetermined intervals. Each step of the dose estimation method according to claim 7 or 8;
updating a work plan for handling the work object based on the estimated dose rate at the monitoring position and an upper limit of the dose rate to be observed;
presenting the updated new work plan to a worker, and executing work on the work object based on the new work plan.