JP2015137984A - Emission amount estimation apparatus, emission amount estimation method, and emission amount estimation program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly calculate an emission amount after spatial suspended matter is emitted from an emission point.SOLUTION: An emission amount estimation apparatus which estimates an emission amount of spatial suspended matter emitted from an emission point has: a storage unit which stores a plurality of pieces of observational data including relationship between a position of spatial suspended matter and an observation result; and a calculation unit which determines an environmental variable for comparison and an observation position, estimates an emission amount from an emission point on the basis of each piece of observational data, calculates a value of the environmental variable for comparison of the observation position on the basis of the estimated emission amount, evaluates reliability on the basis of a calculation result, compares an evaluated result, and outputs a comparison result.

Description

  The present invention relates to a release amount estimation device, a release amount estimation method, and a release amount estimation program for estimating a release amount of a space suspended substance.

  As a method for estimating the amount of space suspended matter released from the release point into the atmosphere, there is a method described in Patent Document 1. By using the method of Patent Document 1, when a radioactive substance is released due to an accident at a nuclear facility such as a nuclear power plant, or when a harmful substance is released from a facility, the space floating released from the release point The amount of substance released can be estimated.

JP2013-65208A

  With the method described in the above-mentioned Patent Document 1, it is possible to predict the amount of space suspended matter released from the release point, and to increase the accuracy of diffusion prediction. Here, the observation data of the suspended matter can be measured by a plurality of methods and parameters. Emissions can be estimated using observation data in multiple forms (number of observation points, number of countries at the time of observation, observation method, etc.), but there are as many estimation results as the number of observation data. The evaluation of the reliability of the estimation result becomes trial and error and takes time.

  The present invention has been made in view of the above circumstances, and a radioactive substance release amount estimation device and a radioactive substance release amount estimation capable of quickly calculating a release amount after a space suspended substance is released from a release point. It is an object of the present invention to provide a method and a radioactive substance emission estimation program.

  The present invention for solving the above-described problem is a release amount estimation device for estimating the release amount of space suspended matter released from a release point, and includes a plurality of relationships including the relationship between the position of the space suspended matter and the observation result. A storage unit for storing observation data, and determining a comparison environment variable and observation position, estimating the release amount from the release point based on each observation data, and based on the estimated release amount, for the comparison And calculating a value of the environmental variable at the observation position, evaluating reliability based on the calculation result, comparing the evaluated results, and outputting a comparison result.

  Here, it is preferable that the environmental variable is at least one of an air concentration, a soil contamination concentration, and an air dose.

  Moreover, it is preferable that the said calculating part extracts the information with the high measured value resulting from a space suspended material from the said observation data, and estimates the discharge | release amount from the said discharge | release point based on the extracted observation data.

  In addition, the calculation unit identifies observation data with the highest reliability based on the comparison result, and performs a diffusion simulation of the suspended solid matter with the release amount from the release point calculated based on the specified observation data. It is preferable to determine the arrangement of the observation positions based on the distribution of the suspended matter in space.

  In addition, the calculation unit identifies observation data with the highest reliability based on the comparison result, and performs a diffusion simulation of the suspended solid matter with the release amount from the release point calculated based on the specified observation data. It is preferable to calculate the amount of deposition on the seawater surface.

  In addition, the storage unit is a transfer function that specifies a relationship between an observation value of the space suspended material at an observation point calculated in advance based on a diffusion simulation process of the space suspended material and a release amount of the space suspended material. Is stored for each of a plurality of atmospheric information, and the calculation unit inputs the current atmospheric information when the space suspended substance is actually released, and is stored in the storage unit corresponding to the atmospheric information. Using the newly observed observation value at the observation point and the read transfer function, the amount of release of the space suspended matter at the release point based on the newly observed value is estimated. It is preferable to provide a discharge amount estimation unit.

  In addition, the emission amount estimation unit is configured to determine the observation values observed at each of the plurality of different observation points and the plurality of different observation points according to a transfer function read from the storage unit based on the current atmospheric information. It is preferable to estimate the release amount of the space suspended substance that minimizes the total residual value of the estimated observation value.

  Further, the atmospheric information is wind state information, or atmospheric stability information, or a combination thereof, and the storage unit is configured to store the air information for each of the atmospheric information represented by wind state information, atmospheric stability, or a combination thereof. Preferably, the transfer function is stored.

  Further, the calculation unit specifies a relationship between the observation value of the spatial suspended substance at the observation point and the released amount of the spatial suspended substance based on the diffusion simulation process of the suspended particulate matter and the atmospheric information. It is preferable that a transfer function calculating unit that calculates a transfer function to be performed before the space suspended substance is actually released and is stored in the storage unit is preferably provided.

  Further, when the diffusion simulation process is a particle method or a difference method, and the transfer function calculation unit is the difference method, the transfer function is calculated at a predetermined short time interval, and the storage unit is It is preferable to update every calculation.

  In addition, the space suspended material is a radioactive material having a plurality of different nuclides, and the transfer function calculating unit reflects the transfer function reflecting the influence of the radiation dose due to the half-life of the nuclide over time for each nuclide. It is preferable to calculate and store in the storage unit.

  Moreover, it is preferable that the said transfer function calculation part calculates the said transfer function reflecting the influence of the radiation dose from the said nuclide which exists in the ground surface by the influence of at least one of dry deposition or wet deposition.

  The present invention for solving the above-described problem is a release amount estimation method for estimating the release amount of a space suspended material released from a release point, and includes a plurality of relationships including the relationship between the position of the space suspended material and an observation result. Observation data, and determine environmental variables and observation positions for comparison, estimate the release amount from the release point based on each observation data, and based on the estimated release amount, the comparison observation position Is calculated, the reliability is evaluated based on the calculation result, the evaluation result is compared, and the comparison result is output.

  In order to solve the above-described problems, the present invention provides a plurality of observations including the relationship between the position of the spatially suspended matter and the observation result by the release amount estimating device for estimating the released amount of the suspended matter released from the release point. Acquire data, determine environment variables and observation positions for comparison, estimate the release amount from the release point based on each observation data, and based on the estimated release amount, the environment at the observation position for comparison The variable value is calculated, the reliability is evaluated based on the calculation result, the evaluated result is compared, and the comparison result is output.

  According to the present invention, it is possible to quickly calculate the release amount after the space suspended substance is released from the release point.

FIG. 1 is a schematic diagram illustrating a configuration of a release amount estimation system according to the present embodiment. FIG. 2 is a block diagram illustrating a configuration of a discharge amount estimation device of the discharge amount estimation system. FIG. 3 is an explanatory diagram showing an example of a list of observation data. FIG. 4 is a flowchart showing an example of the procedure of the release amount estimation method. FIG. 5 is a diagram illustrating a processing flow of the transfer function calculation unit. FIG. 6 is a diagram illustrating an outline of processing of the transfer function calculation unit. FIG. 7 is a diagram illustrating a processing flow of the discharge amount estimation unit. FIG. 8 is a flowchart showing an example of the procedure of the release amount estimation method. FIG. 9 is a flowchart illustrating an example of the procedure of the release amount estimation method. FIG. 10 is a flowchart illustrating an example of the procedure of the release amount estimation method.

  DESCRIPTION OF EMBODIMENTS Hereinafter, modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by the content described in the following embodiment. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the constituent elements disclosed in the following embodiments can be appropriately combined without departing from the scope of the present invention. Here, in the present embodiment, the description will be made on the case where the space suspended substance is a radioactive substance and the release point is a nuclear facility, but the present invention is not limited to this. Various materials can be used as the space suspended material, and various facilities and points can be used as the release point. For example, various chemical substances can be targeted as the space suspended substance.

  The discharge amount estimation system according to the present embodiment will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating a configuration of a release amount estimation system according to the present embodiment. As shown in FIG. 1, a release amount estimation system (hereinafter referred to as “estimation system”) 10 predicts the diffusion state of radioactive substances released from the nuclear facility 8. The nuclear facility 8 is a facility that holds radioactive substances such as a nuclear power plant. The estimation system 10 predicts the amount of radioactive material released when an accident or the like occurs in the nuclear facility 8. The estimation system 10 of the present embodiment can estimate the diffusion state and the like in addition to the release amount.

  The estimation system 10 includes a plurality of observation devices 12, a weather database 14, and a release amount estimation device (hereinafter referred to as “estimation device”) 16. The observation device 12 is a device that measures a radiation dose (dose rate) or the like at an observation position. The observation apparatus 12 measures the radiation dose, the air concentration, and the soil contamination concentration at the measurement position by measuring the radiation dose and the like. Note that the observation device 12 may use a different device as a measurement device depending on which of the environmental variables (parameters) to be observed, that is, the air dose, the air concentration, or the soil contamination concentration is detected. The observation device 12 includes a device installed at a fixed observation facility (fixed point) and a device mounted on a mobile object such as the airplane 2 or the automobile 4. The observation device 12 installed at the fixed point continuously measures the radiation dose at the installed position. An observation device 12 mounted on a moving body such as an airplane (aircraft) 2 or an automobile 4 moves an observation position with the movement of the moving body, and measures radiation doses at a plurality of positions with one observation device 12. The observation device 12 of the present embodiment is a γ observation device that measures γ rays. Observation devices 12 installed at fixed points are scattered around the nuclear facility 8. The arrangement interval of the observation devices 12 is not particularly limited. For example, the observation devices 12 are arranged at a site boundary of the nuclear facility 8 at intervals of several hundred meters. Moreover, the observation apparatus 12 installed at the fixed point is arranged in a range of 400 km centering on the nuclear facility 8 at an interval of 1 km or more, for example. The observation device 12 outputs the measured dose information (observation dose information) to the estimation device 16. The output method may be output via communication or output via a recording medium. In the estimation system 10, the position where the observation device 12 is arranged becomes the observation position.

  The meteorological database 14 stores meteorological information in a range (observation range) in which the radiation dose including the nuclear facility 8 is observed, specifically, weather, wind speed, wind direction, rainfall, temperature, and the like. The weather database 14 may further predict weather conditions in the observation range based on various conditions. The weather database 14 outputs the weather conditions in the observation range to the estimation device 16. The weather database 14 of the present embodiment is separate from the estimation device 16, but may be integrated.

  FIG. 2 is a block diagram illustrating a configuration of a discharge amount estimation device of the discharge amount estimation system. The estimation device 16 is based on the radiation data (observation data) at the observation position observed by the observation device 12, the weather conditions provided from the weather database 14, various stored information, and the like. Estimate the amount released. The estimation device 16 includes a calculation unit 20, a storage unit 22, an input unit 24, an output unit 26, a communication unit 28, and a medium reading unit 30. The estimation device 16 serves as an acquisition unit from which the input unit 24, the communication unit 28, and the medium reading unit 30 acquire information.

  The calculation unit 20 includes a CPU (Central Processing Unit) as a calculation means and a memory as a storage means, for example, a RAM (Random Access Memory), and executes various programs by executing programs using these hardware resources. Realize the function. Specifically, the arithmetic unit 20 reads a program stored in the storage unit 22 and expands it in a memory, and causes the CPU to execute instructions included in the program expanded in the memory. The arithmetic unit 20 reads / writes data from / to the memory and the storage unit 22 and controls the operation of the communication unit 28 and the like according to the execution result of the instruction by the CPU.

  The calculation unit 20 includes a transfer function calculation unit 20A, a discharge amount estimation unit 20B, a comparison unit 20C, an arrangement selection unit 20D, and a deposition amount calculation unit 20E. The calculation unit 20 executes the programs stored in the storage unit 22 to realize the functions of the above units.

  The transfer function calculator 20A calculates the transfer function before the radioactive substance is actually released. The transfer function calculation unit 20A stores the calculated transfer function in the transfer function data 22F of the storage unit 22.

  The release amount estimation unit 20B acquires the current atmospheric information when the radioactive substance is actually released from the weather database 14, and corresponds to the current atmospheric information among the transfer functions of the radioactive substance calculated for a plurality of atmospheric information. The transfer function to be read is read from the transfer function data 22F of the storage unit 22. The release amount estimation unit 20B estimates the release amount of the radioactive substance at the release point based on the newly observed values using observation data 22E described later and the read transfer function. Note that the observation data is input by the user through the input unit 24, whether acquired from the observation data 22 </ b> E, acquired from the observation device 12 via the communication unit 28, or acquired via the medium reading unit 30. May be used.

  The comparison unit 20C compares the release amount estimated for each observation data by the release amount estimation unit 20B, and calculates a comparison result. Specifically, the comparison unit 20C performs a calculation set for the release amount, calculates a value for comparison, calculates reliability from the calculation result, compares the calculated reliability, and compares Output the result.

  The arrangement selection unit 20D performs processing using the discharge amount specified by the comparison unit 20C and selects the arrangement of the observation positions. The deposition amount calculation unit 20E performs processing using the release amount specified by the comparison unit 20C, and calculates the deposition amount on the sea surface.

  The storage unit 22 includes a nonvolatile storage device such as a magnetic storage device or a semiconductor storage device, and stores various programs and data. The program stored in the storage unit 22 includes a release amount estimation program 22A for executing the functions of a release amount estimation unit 20B for estimating the release amount of a radioactive substance and a comparison unit 20C for comparing the estimation results, and for estimation of the release amount. A transfer function calculation program 22B for executing the function of the transfer function calculating unit 20A for calculating the transfer function to be used, an arrangement selection program 22C for executing the function of the arrangement selecting unit 20D for selecting the arrangement of the observation position, and the amount of deposition on the sea surface And a deposition amount calculation program 22D for executing the function of the deposition amount calculation unit 20E. The transfer function calculation program 22B, the arrangement selection program 22C, and the deposition amount calculation program 22D are programs for calculating data used in the release amount estimation program 22A, and may be included in a part of the release amount estimation program 22A. The program described above may be a so-called difference file (difference program) that can realize the above-described functions in combination with a program that has already been stored.

  The data stored in the storage unit 22 includes observation data 22E and transfer function data 22F. The observation data 22E stores an observation method, parameters to be observed, observation positions, and values measured by the observation device 12. The observation data 22E also includes information necessary for estimating the amount of radioactive material released, such as information on the position (observation position) where the observation device 12 is installed, topographic data of the observation range, and the like.

  FIG. 3 is an explanatory diagram showing an example of a list of observation data. As shown in FIG. 3, the observation data includes three types of observation methods: fixed points, airplanes, and automobiles. The measurement parameters (environment variables) include air dose, air concentration, and soil contamination concentration. measure. Although only six observation data are shown in FIG. 3, the number is not particularly limited.

  The transfer function data 22F is a transfer function that specifies the relationship between the observed value (calculated value) of the radioactive substance at the observation point calculated in advance based on the diffusion simulation process of the radioactive substance and the release amount of the radioactive substance. It is stored for each of a plurality of atmospheric information.

  A part or all of the program and data to be stored in the storage unit 22 in FIG. 2 is stored in another device that can communicate with the communication unit 28 via the network, and downloaded to the storage unit 22 as necessary. It is also good to do. 2 may be stored in a storage medium and read by the medium reading unit 30 as necessary. The program and data stored in the storage unit 22 in FIG.

  The input unit 24 is a device such as a keyboard, mouse, touch panel, etc., on which a user or an operator inputs an operation. The output unit 26 is a device that outputs various information such as characters and graphics. The output unit 26 is a liquid crystal panel, an organic EL (Organic Electro-Luminescence) panel, a display device such as a projector, a printing device, or the like. The communication unit 28 controls transmission / reception of information with other devices including the observation device 12 and the weather database 14 based on a predetermined communication protocol. The medium reading unit 30 reads a program and data from a portable non-transitory storage medium such as an optical disk, a magneto-optical disk, and a memory card.

  Next, the control operation of the estimation system 10 and the estimation device 16, that is, an example of the radioactive substance release amount estimation method of this embodiment will be described. FIG. 4 is a flowchart showing an example of the procedure of the release amount estimation method. In the process illustrated in FIG. 4, the estimation device 16 uses the release amount estimation program 22 </ b> A and the transfer function calculation program 22 </ b> B stored in the storage unit 22, and the calculation unit 20 controls the operation of each unit. This can be realized by performing arithmetic processing on the acquired information. Note that the estimation device 16 may start the processing when detecting information determined to contain a radioactive substance from the observation data supplied from the observation device 12, or start the processing by a user operation. It may be.

  The estimation device 16 determines an environmental variable for comparison and an observation position (step S12). Here, the environmental variable is a parameter that can be calculated based on the release amount, and is a value that can be calculated based on the observation result of the observation device 12 itself or on the observation result. The observation position may be one point or a plurality of points. The environmental variable for comparison and the observation position are information used for reliability evaluation.

  Next, the estimation device 16 specifies observation data (step S14). Here, the estimation device 16 specifies one observation data among a plurality of observation data to be evaluated. When the estimation device 16 identifies the observation data, the estimation device 16 performs a release amount estimation calculation using the observation data (step S16). Thereby, the estimated release amount based on the observation data is calculated. A method for calculating the release amount will be described later.

  After calculating the release amount, the estimation device 16 calculates an environmental variable at the observation position for comparison based on the estimated release amount (step S18). The estimation device 16 performs the diffusion simulation of the radioactive substance based on the release amount, and thereby the value of the environmental variable at the observation position set in step S12 when the release amount of the radioactive substance is released from the release point. calculate.

  After calculating the value of the environment variable at the observation position, the estimation device 16 evaluates the reliability based on the calculation result of the observation data (step S20). The estimation device 16 calculates a reliability measure by comparing the value of the environmental variable at the observation position calculated in step S18 with a reference value. The set observation data can be used as the reference value. As the reference value, one observation data may be used, or a result obtained by calculating a plurality of observation data, for example, an average value may be used.

Estimating device 16, the confidence measure can be used _{Factor2 (Fraction of X p within a} factor of two of X o) and the mean square error. The definition formula of Factor 2 is as follows when the reference value is X ₀ and the calculated value is X _p .

The mean square error is represented by the following equation.

  When the estimation device 16 evaluates the reliability, the estimation device 16 determines whether calculation of all observation data is completed (step S22). When the estimation device 16 determines that all of the observation data has not been calculated (No in step S22), that is, there is observation data that has not been calculated, the estimation device 16 returns to step S14, Processing from step S14 to step S20 is performed.

  When it is determined that the calculation of all observation data has been completed (Yes in step S22), the estimation device 16 compares the reliability evaluation results (step S24) and outputs the comparison results (step S26). This process ends. As comparison results, the reliability evaluation results for each observation data may be displayed in a list, or the observation data having the highest reliability and the evaluation results may be displayed.

  In this way, the estimation device 16 calculates the release amount for each observation data, performs an operation using the release amount, and evaluates the reliability based on the result, thereby improving the reliability of each observation data. Can be determined. Thereby, observation data with high reliability can be calculated by calculation, and observation data that can be used effectively can be determined in a short time. That is, while it is difficult to evaluate the reliability only by the relationship between the observation data and the release amount, the estimation device 16 can automatically output the reliability evaluation result.

  Next, the procedure for estimating the amount of release will be described with reference to FIGS. FIG. 5 is a diagram illustrating a processing flow of the transfer function calculation unit. FIG. 6 is a diagram illustrating an outline of processing of the transfer function calculation unit according to the present embodiment. FIG. 7 is a diagram illustrating a processing flow of the discharge amount estimation unit. The estimation device 16 estimates the release amount of the radioactive substance released at the release point by using the observation value obtained from the observation device 12 and the transfer function matrix stored in the transfer function data 22F of the storage unit 22. .

  First, the transfer function calculation unit 20A receives an input of atmospheric information (see reference numeral 401 in FIG. 6) (step S101). The atmospheric information is wind state information, atmospheric stability, or a combination thereof. The wind state information is information on a wind direction or a wind speed or a combination thereof. In this embodiment, it is assumed that the wind state information indicates 16 directions of the wind direction, and the atmospheric stability is information expressed numerically with respect to three levels of stability such as static, dynamic, and turbulent. That is, in this embodiment, the atmospheric information indicates 16 × 3 = 48 types of atmospheric information. The wind state information may indicate a further stepwise wind speed, the wind speed may be three stages of large, medium, and small, and the air information may indicate any of 16 × 3 × 3 = 144 air information. . The wind state information and the atmospheric stability may be other numbers, orientations, and number of steps, and can be determined as appropriate.

Next, the transfer function calculation unit 20A assumes that the unit release amount Q (t _i ) of the radioactive substance is released at one time t _i (for example, i = 2) having a plurality of consecutive times, and the time t _i Information on (i = 2) is acquired (step S102). Radioactive material is material discharged from the factory into the air. When the time _t i (i = 2) in the actual unit discharge amount from the discharge point Q _{(t i)} is released, the unit discharge amount of each successive times Q _{(t i)} is represented by the following formula (1) (See reference numeral 402 in FIG. 6). It is assumed that the radioactive substance of the unit release amount is not released at a time other than the time t _i (i = 2).
Q (t _i ) = [Qt1, Qt2,..., Qtn]
= [0, 1.0, 0,..., 0] (1)
The transfer function calculation unit 20A may accept information at time t _i (i = 2) by input from the user.

The transfer function calculation unit 20A estimates the radiation dose C (ij) at a certain time t _i at the observation point j when the received atmospheric information is received (step S103). Here, j indicates an observation point (j = 1, 2,... N). There are N observation points. Note that an observed value C (ij) at a certain observation point j based on the release of the radioactive substance amount of the unit release amount Q (t _i ) at time t _i (for example, i = 2) is expressed by the following formula (2 ) (See reference numeral 403 in FIG. 6).
C (ij) = [C1, C2,... CN] (2)

The relational expression (linear simultaneous equation) between the unit release amount Q (t _i ) of the radioactive substance at the release point and the observed value C (ij) at the observation point j is expressed by the equation (3) using the transfer function matrix M (ij). ).
C (ij) = M (ij) × Q (t _i ) (3)
Therefore, the observed value C (ij) that can be observed at a certain observation point j when the unit release amount of the radioactive substance is released is Q (t _i ) = [0, 1.0, ... Can be calculated by substituting 0] (see reference numeral 404 in FIG. 6).

Hereinafter, calculation of the transfer function matrix M (ij) in advance by a diffusion simulation (diffusion calculation) by the transfer function calculating unit 20A will be described. Specifically, the transfer function calculation unit 20A uses a particle method simulation (also referred to as a particle diffusion model or a particle method) for diffusion calculation when a radioactive substance having a unit release amount Q (t _i ) is released at time t _i. Do it.

First, the transfer function calculation unit 20A calculates a state in which particles are floating at a spatial position F (x, y, z) having a certain relative positional relationship with the observation point j at time t _i by particle method simulation. (The spatial position F is a position with the emission point as the origin). Then, the transfer function calculating unit 20A obtains an observed value (calculated value) C (ij) at a certain time t _i at a certain observation point j. For example, in the present embodiment, the radiation dose C (ij) at a certain time t _i at a certain observation point j is estimated (radiation dose C (Bq / m ³ )). At this time, the air dose D0 at the observation point j due to one radioactive substance particle is calculated by the equation (4) using the spatial concentration of the radioactive substance by diffusion calculation.
D0 = F (Q, r) (4)
In the formula (4), Q is the radiation dose per unit time (1 Bq (becquerel) / s (second)) according to the nuclide. R represents the distance between the position of the radioactive material (nuclide) and the observation point j due to diffusion.

If T particles are released, the particles are present in the spaces from F1 to FT with a radioactivity (Bq). Therefore, the transfer function calculation unit 20A adds the doses D0 from the respective particles, and obtains the radiation dose C (ij) at a certain time t _i at the observation point j. The above D0 indicates the air dose from the radioactive substance floating in the atmosphere, and the dose D0 from each particle is added to obtain the radiation dose C (ij) at an observation point j at a certain time t _i. However, the air dose D1 from the radioactive material deposited on the ground is calculated, and the dose D1 from each particle deposited on the ground is added to the dose D0 from each particle in the air to obtain a certain time t at the observation point j. The radiation dose C (ij) at _i may be obtained. The transfer function calculating unit 20A considers one or both of the radioactive substance deposited on the ground as a radioactive substance that naturally deposits on the ground (dry deposition) and a radioactive substance that deposits on the ground surface due to rain (wet deposition). Then, the amount of the deposited radioactive material is calculated.

In the above example, the diffusion of the radioactive substance is calculated using the particle method. However, in another embodiment, the calculation may be performed using the difference method. In the case of the difference method, diffusion calculation is performed on the assumption that a radioactive substance having a certain concentration (Bq / m ³ ) exists in a space S surrounded by certain ranges of Δx, Δy, and Δz. There are several known techniques for determining the dose from the difference method, but any difference technique may be used to determine the radiation dose C (ij) at an observation point j at a certain time t _i. . In the difference method, the simplest method is a method of converting a dose from a spatial concentration using a conversion coefficient as shown in Equation (5).
D = KC (5)
In Expression (5), K represents a conversion coefficient (conversion coefficient for converting Bq / m ³ into Sv), and C represents a spatial concentration (Bq / m ³ ). Here, the radioactive substances present in the space S in the difference method are mixed with radioactive substances released at different times. Therefore, when the difference method is used, the concentration of the radioactive substance existing in the space S is divided for each degree of influence due to the difference in the release time, and the observed value (radiation dose) C (ij) at the observation point j is obtained. I can't. Therefore, the transfer function calculation unit 20A obtains an observation value (calculated value of radiation dose) C (ij) at a certain time t _i at a certain observation point j by a difference method at a predetermined short time interval (several time interval). In each case, the transfer function data 22F in the storage unit 22 may be updated.

Then, the transfer function calculation unit 20 </ b> A uses the unit release amount Q (t _i ) of the radioactive substance and the observation point at each time t _i (i = 1, 2,..., N) estimated by the diffusion simulation. The transfer function matrix M (ij) is derived by the above equation (3) using the observed value (calculated value) C (ij) at j (step S104).

  In more detail, the said Formula (3) can be represented like the following formula | equation (6). That is, the relationship between the observed value (calculated value) C (ij) and the released amount Q (ij) at the observation point j is represented by transfer functions (M11, M21,... Mi1), (M21, M22,... Mi2). ), (M13, M23,..., Mi3),..., (M1j, M2j,... Mij) can be expressed as in Expression (6).

The transfer function calculating unit 20A, a plurality of observation points j, repeats the calculation of the radiation dose C (ij) of a plurality of successive respective times t _i, the time each, for each observation point j, equation (6) The transfer function matrix M (ij) used in the above is calculated.

That is, since “C1j = M11 · Q1”, C1j and Q1 are known by estimation and setting, M11 can be calculated. Further, since C1j and Q2 are known by estimation and setting by “C1j = M21 · Q2”, M21 can be calculated. Similarly, from equation (6), M1 can be calculated because C1j and Q2 are known by estimation and setting from “Cij = M21 · Q2”. In this way, the transfer function calculation unit 20A repeatedly estimates the radiation dose C (ij) at a plurality of consecutive times t _i for a plurality of observation points j for each observation point j. A transfer function matrix M (ij) used in Expression (6) is calculated.

  The transfer function calculation unit 20A stores the transfer function matrix M (ij) calculated for certain atmospheric information in the transfer function data 22F of the storage unit 22 (step S105). Further, the transfer function calculating unit 20A indicates that the wind state information indicates any one of the 16 directions of the wind direction, and the atmospheric stability includes 16 × 3 = 48 ways of atmospheric information indicating the stability in three stages of static, dynamic, and turbulence. The transfer function matrix M (ij) is repeatedly calculated and stored in advance in the transfer function data 22F of the storage unit 22. As described above, the wind state information and the atmospheric stability may be other numbers, orientations, and number of steps, so if there are different numbers of orientations and stability numbers, The transfer function matrix M (ij) is iteratively calculated by that amount. The transfer function matrix M (ij) in each atmospheric state can be calculated in advance before the radioactive substance is actually released by the above processing.

  Next, with reference to FIG. 7, when the radioactive substance is actually released, the processing flow in the case where the release amount estimation device 16 estimates the release amount at the release point using the transfer function matrix M (ij) will be described. To do.

When the estimation device 16 starts the estimation process of the release amount (step S201), the estimation device 16 acquires information of the observation value C (ij) detected at each time t _i determined from each observation device 12, that is, observation data. (Step S202). The transfer function calculating unit 20A, the observed values of the observation device 12 measured every time of detecting the time t _i that are separated time stipulated C (ij), it may be accepted by an input directly from the user. As described above, the relational expression (linear simultaneous equation) between the unit release amount Q (ti) of the radioactive substance at the release point and the observed value C (ij) at the observation point j is expressed by using the transfer function matrix M (ij). It can be expressed as (3) or (6).

  The estimation device 16 acquires information of the weather database 14 by the emission amount estimation unit 20B and inputs the current atmospheric information (step S203). The estimation device 16 reads the transfer function matrix M (ij) stored in association with the current atmospheric information from the transfer function data 22F (step S204).

  The estimation device 16 uses the emission amount estimation unit 20B to obtain the residual of the following equation (7) using the obtained observation value C (ij) from each observation device 12 and the read transfer function matrix M (ij). A unit emission amount Q (ti) = [Qt1, Qt2,..., Qtn] that minimizes the norm π is estimated (step S205). In equation (7), the variable N indicates the number of observation points j (k = 1,..., N).

That is, the observation point j is a, b, in some cases three places of c (N = 3), _C1j the equation (6) at the observation point _{j a a = M11 a · Q1} + M21 a · Q2 +, ..., + Mi1 a・ Qi
C2j _a = M12 _a · Q1 + M22 _a · Q2 +, ..., + Mi2 _a · Qi
...
Cij _a = M1j _a · Q1 + M2j _a · Q2 +, ..., + Mij _a · Qi
And
_C1j from the equation (6) at the observation point _{j b b = M11 b · Q1} + M21 b · Q2 +, ..., + Mi1 b · Qi
C2j _b = M12 _b · Q1 + M22 _b · Q2 +, ..., + Mi2 _b · Qi
...
Cij _b = M1j _b · Q1 + M2j _b · Q2 +, ..., + Mij _b · Qi
And
At the observation point j _c , C1j _c = M11 _c · Q1 + M21 _c · Q2 +,..., + Mi1 _c · Qi
C2j _c = M12 _c · Q1 + M22 _c · Q2 +, ..., + Mi2 _c · Qi
...
Cij _c = M1j _c · Q1 + M2j _c · Q2 +, ..., + Mij _c · Qi
So that
C1j _a = M11 _a · Q1 + M21 _a · Q2 +, ..., + Mi1 _a · Qi
C1j _b = M11 _b · Q1 + M21 _b · Q2 +, ..., + Mi1 _b · Qi
...
C1j _c = M11 _c · Q1 + M21 _c · Q2 +, ..., + Mi1 _c · Qi
Using,
{(M11 _a · Q1 + M21 _a · Q2 +,..., + Mi1 _a · Qi) −C1j _a } ²
{(M11 _b · Q1 + M21 _b · Q2 +,..., + Mi1 _b · Qi) −C1j _b } ²
...
{(M11 _c · Q1 + M21 _c · Q2 +,..., + Mi1 _c · Qi) −C1j _c } ²
.., Qi is calculated such that the unit emission amount Q (ti) = Q1, Q2,. That is, the emission amount estimation unit 20B estimates an emission amount that minimizes the residual norm π (total residual value) between the observed value and the calculated value. The release amount estimation device 16 outputs the estimated release amount to, for example, a monitor.

  Through the above processing, the estimation device 16 estimates the release amount at the release point using the transfer function matrix corresponding to the atmospheric information at the time when the radioactive substance is released among the transfer function matrices calculated in advance for each atmospheric information. To do. Therefore, the time for calculating the transfer function matrix is shortened, and the release amount can be estimated quickly.

In addition, the amount Dd (Bq / m ² / s) per unit time for dry deposition of the radioactive substance (nuclide) described above can be calculated by Expression (8). Further, the amount Dw (Bq / m ² / s) per unit time during which the radioactive substance is wet-deposited can be calculated by the equation (9). If the transfer function matrix M (ij) is calculated based on the simulation result of the observation value at the observation point j in consideration of the air dose from the dry or wet deposition radioactive material, the radiation dose can be estimated with higher accuracy. A transfer function matrix M (ij) can be calculated.

Dd = CVg (8)
Dw = ∫ΛCdz (9)

In the formulas (8) and (9), C represents the concentration (Bq / m ³ ) of the radioactive substance. Moreover, in Formula (8), Vg has shown the deposition rate (cm / s). Generally, Vg = 0.3 (cm / s) is used. In Equation (9), Λ represents a cleaning coefficient (1 / s), z represents a vertical direction, and can be represented by Equation (10).
Λ = aP ^b (10)
P is the precipitation intensity (mm / hr), and a and b are parameters (generally values are a = 1E-4, b = 0.5).

  Further, in calculating the transfer function matrix M (ij), the transfer function calculating unit 20A takes into account the difference in half-life for each nuclide of the radioactive substance, and reflects the effect of the half-life for each nuclide. M (ij) may be calculated and stored in the transfer function data 22F of the storage unit 22. Here, the relational expression (linear simultaneous equation) between the unit release amount Q (ti) of the radioactive substance at the release point and the observed value C (ij) at the observation point j when the above-mentioned half-life is not taken into consideration is the transfer function matrix M Using (ij), it could be expressed as in equation (3). On the other hand, the relational expression (linear simultaneous equation) between the unit release amount Q (ti) of the radioactive substance at the release point and the observed value C ′ (ij) at the observation point j when considering the half-life is the observed value C ( Since ij) can be expressed as equation (11), equation (12) is obtained.

C (ij) = C ′ (ij) exp (−λt) (11)
C ′ (ij) exp (−λt) = M (ij) × Q (t _i ) (12)
In equations (11) and (12), t represents time (s), and λ represents a decay constant (1 / s).

推定装置１６は、上記式に基づいた連立方程式を残差ノルムπが最小となるように解くことでも、各時刻の放出量ｑ_ｉを算出することができる。 Further, the transfer function of the release time (i) with respect to the observation time and the observation point (k) is Φ _ki , the observation value at the observation point (k) is f _k, and the release amount at the release time (i) is q _i. When the observation time and the number of observation points are N and the number of emission time divisions is M, the residual norm π can be expressed by the following equation.

The estimation device 16 can also calculate the emission amount q _i at each time by solving the simultaneous equations based on the above equations so that the residual norm π is minimized.

  Here, as described above, the space suspended substance is not limited to a radioactive substance, and may be a chemical substance contained in smoke discharged from a factory such as a chemical plant. In this case, the release amount estimation system 10 may install a large number of observation devices 12 at 100 or more locations around the chemical plant. The release amount estimation device 16 calculates a transfer function matrix M (ij) based on the observation values observed in 100 or more observation devices 12, stores the transfer function matrix M (ij) in the transfer function data 22F, and actually performs an accident or the like. The release amount of the chemical substance at the release point when the chemical substance is released by may be estimated. Alternatively, the gas emission amount may be estimated using the gas concentration data observed by the observation device 12.

  Further, the release amount estimation system 10 may specify the release point in addition to the release amount by the release amount estimation device 16. In this case, the discharge amount estimation device 16 calculates the residual total value (π) for each discharge point, and the point where the calculated residual total value (π) is the smallest is the most reliable as the point of the discharge point. Judge that the degree is high. Accordingly, it is possible to obtain the release location and the release amount in a short calculation time without specifying the release location by repeated calculation.

  Moreover, since the said effect can be acquired, although it is preferable for the discharge | emission amount estimation apparatus 16 to calculate and memorize | store a transfer function for every atmospheric | air information beforehand, and to use the memorize | stored transfer function, it is not limited to this. Various methods can be used as a method of estimating the release amount.

  Next, another example of the release amount estimation method will be described with reference to FIG. FIG. 8 is a flowchart showing an example of the procedure of the release amount estimation method. Of the processing procedures shown in FIG. 8, the same processing procedures as the processing procedures shown in FIG.

  When the estimation device 16 determines the environmental variable for comparison and the observation position (step S12), the estimation device 16 specifies the observation data (step S14). Here, the estimation device 16 specifies one observation data among a plurality of observation data to be evaluated. When the estimation device 16 specifies the observation data, it performs data extraction processing (step S40). Specifically, the estimation device 16 evaluates the parameters (air dose, air concentration, soil contamination concentration) used for calculating the release amount in the observation data at each observation point and each time, and some data is obtained. Extract. Specifically, a measured value that is equal to or smaller than a predetermined value, for example, one tenth of the peak or a value that is one digit smaller than the peak is removed from the observation data. In the extraction process, data of observation points with small measurement values may be removed, or time zones with low measurement values may be removed. When the estimation device 16 performs the extraction process on the observation data, the estimation device 16 performs the emission amount estimation calculation using the observation data obtained by extracting the data (step S16). The subsequent processing is the same as the processing shown in FIG.

  As described above, the estimation apparatus 16 can reduce the calculation load and process highly reliable data by extracting the data. In other words, the larger the value of the observation data, the smaller the measurement error of observation. Thereby, this embodiment can make the precision of estimation of discharge | release amount higher by using only data with a big value.

  Moreover, the estimation apparatus 16 can also perform various processes using the comparison result of discharge amount. FIG. 9 is a flowchart illustrating an example of the procedure of the release amount estimation method. The estimation apparatus 16 can implement the process shown in FIG. 9 by executing the process in the arrangement selecting unit 20D. The estimation device 16 reads the amount of comparison release (step S302). Here, the discharge amount of the comparison result to be read is the discharge amount of the evaluation result with the highest reliability. When the estimation device 16 reads the release amount, it uses the release amount of the comparison result to calculate the soil contamination concentration and calculate the soil contamination distribution (step S304). The estimation device 16 can calculate the distribution of the soil contamination concentration by performing a diffusion simulation based on the release amount.

  After calculating the soil contamination distribution, the estimation device 16 determines whether or not there is an observation point in a portion with a high concentration (step S306). The estimation device 16 divides the area where the soil contamination distribution is calculated into areas, and determines whether there is an area where the observation point is not installed in an area where the soil contamination concentration is higher than the threshold value. If the estimation device 16 determines that there is an observation point (Yes in step S306) and that there is data in a portion with a high density, this processing ends.

  When it is determined that there is no observation point (No in step S306), the estimation device 16 adds an observation point to an area with a high concentration (step S308), acquires the observation data after the addition (step S310), and the observation data Based on the above, the release amount is calculated (step S312), and this process is terminated.

  Thus, the estimation device 16 can further increase the calculation accuracy of the estimation of the emission amount by resetting the observation point (observation position) based on the emission amount of the comparison result.

  The estimation device 16 preferably interpolates the added observation data using the added observation data and the observation data in the vicinity before the installation to generate the observation data before the installation. Thereby, calculation can be performed smoothly.

  Since the estimation device 16 can evaluate the observation point (observation position) using the soil contamination distribution based on the soil contamination concentration, it is possible to perform the evaluation with a parameter with little change. The amount of release can be recalculated with higher accuracy. The parameter calculated in step S304 is preferably calculated as a soil contamination concentration as described above, but is not limited thereto, and the distribution may be calculated by calculating the air concentration or air dose.

  Next, another example of the process using the discharge amount of the comparison result will be described with reference to FIG. FIG. 10 is a flowchart illustrating an example of the procedure of the release amount estimation method. The processing shown in FIG. 10 can be realized by executing processing in the deposition amount calculation unit 20E. The estimation device 16 reads the release amount of the comparison result (step S402), performs a diffusion simulation using the release amount of the comparison result, and calculates the atmospheric concentration (step S404). That is, the air concentration at each position is calculated. After calculating the atmospheric concentration, the estimating device 16 calculates the amount of deposition on the seawater surface based on the calculated atmospheric concentration (step S406), and ends this process.

  The estimation device 16 can evaluate the influence of radioactive substances on the seawater with high accuracy by calculating the deposition amount distribution on the seawater surface using the reliable estimation result of the release amount. In addition, the estimation device 16 estimates the ocean diffusion of radioactive materials (substances to be evaluated) in the ocean, in addition to the amount of radioactive material released from the power plant directly into the seawater. By doing so, the reliability of the evaluation can be increased.

8 Nuclear facilities 10 Release estimation system (estimation system)
12 Observation Device 14 Meteorological Database 16 Emission Estimation Device (Estimation Device)
DESCRIPTION OF SYMBOLS 20 Calculation part 20A Transfer function calculation part 20B Release amount estimation part 20C Comparison part 20D Arrangement selection part 20E Deposition amount calculation part 22 Storage part 22A Release amount estimation program 22B Transfer function calculation program 22C Arrangement selection program 22D Deposition quantity calculation program 22E Observation data 22F transfer function data 24 input unit 26 output unit 28 communication unit 30 medium reading unit

Claims (14)

A release amount estimation device for estimating the release amount of space suspended matter released from a release point,
A storage unit that stores a plurality of observation data including the relationship between the position of the suspended solids and the observation results;
Determine environmental variables and observation position for comparison, estimate the amount of release from the release point based on each observation data, and calculate the value of the environmental variable at the observation position for comparison based on the estimated release amount And a calculation unit that evaluates reliability based on the calculation result, compares the evaluated result, and outputs the comparison result.   The emission amount estimation device according to claim 1, wherein the environmental variable is at least one of an air concentration, a soil contamination concentration, and an air dose.   The said calculating part extracts the information with the high measured value resulting from a space suspended material from the said observation data, and estimates the discharge | release amount from the said discharge | release point based on the extracted observation data, or characterized by the above-mentioned. 2. The discharge amount estimation apparatus according to 2.   The calculation unit identifies observation data with the highest reliability based on the comparison result, performs a diffusion simulation of the suspended solids with the release amount from the release point calculated based on the specified observation data, and The emission amount estimation apparatus according to any one of claims 1 to 3, wherein an arrangement of observation positions is determined based on a distribution of suspended substances.   The calculation unit identifies observation data with the highest reliability based on the comparison result, performs a diffusion simulation of the suspended solids with the release amount from the release point calculated based on the specified observation data, The amount of deposition estimation device according to any one of claims 1 to 3, wherein the amount of deposition on the surface is calculated. The storage unit has a transfer function for specifying a relationship between an observation value of the spatial suspended substance at an observation point calculated in advance based on a diffusion simulation process of the suspended particulate matter and an amount of the released spatial suspended matter, Memorize every air information,
The calculation unit inputs current atmospheric information when the space suspended substance is actually released, reads a transfer function stored in the storage unit corresponding to the atmospheric information, and at the observation point A release amount estimation unit for estimating the amount of release of the space suspended substance at the release point based on the newly observed observation value using the newly observed observation value and the read transfer function is provided. The discharge amount estimation apparatus according to any one of claims 1 to 5.   The emission estimation unit estimates each of the plurality of different observation points based on the observed value observed at each of the plurality of different observation points and a transfer function read from the storage unit based on the current atmospheric information. The release amount estimation device according to claim 6, wherein the release amount of the space suspended matter that minimizes the total residual value of the observed value is estimated.   The atmospheric information is wind state information, or atmospheric stability information, or a combination thereof, and the storage unit is configured to transfer the transfer function for each atmospheric information represented by wind state information, atmospheric stability, or a combination thereof. Is stored, and the release amount estimation device according to claim 6 or 7.   The calculation unit is configured to determine a relationship between an observation value of the space suspended matter at the observation point and a release amount of the space suspended matter based on the diffusion simulation process of the space suspended matter and the atmospheric information. 9. A transfer function calculation unit that calculates a function before the space suspended substance is actually released and stores the function in the storage unit. Release amount estimation device. The diffusion simulation process is a particle method or a difference method,
The transfer function calculation unit, when the difference method is used, calculates the transfer function at a predetermined short time interval, and updates the storage unit each time the calculation is performed. The release amount estimation apparatus described. The space suspended material is a radioactive material having different nuclides,
The transfer function calculating unit calculates, for each nuclide, the transfer function that reflects the influence of the radiation dose due to the half-life of the nuclide over time, and stores the transfer function in the storage unit. The discharge amount estimation apparatus according to 9 or 10.   The transfer function calculation unit calculates the transfer function reflecting the influence of the radiation dose from the nuclide existing on the ground surface due to the influence of at least one of dry deposition and wet deposition. The discharge amount estimation apparatus according to any one of the above. A release amount estimation method for estimating a release amount of space suspended matter released from a release point,
Obtaining a plurality of observation data including the relationship between the position of the suspended matter and the observation results;
Determine environment variables and observation positions for comparison,
Based on the observation data, estimate the release amount from the release point,
Based on the estimated release amount, calculate the value of the environmental variable of the comparative observation position,
Evaluate reliability based on calculation results,
A method for estimating a released amount, comprising comparing the evaluated results and outputting the comparison results. With a release amount estimation device that estimates the release amount of space suspended matter released from the release point,
Obtaining a plurality of observation data including the relationship between the position of the suspended matter and the observation results;
Determine environment variables and observation positions for comparison,
Based on the observation data, estimate the release amount from the release point,
Based on the estimated release amount, calculate the value of the environmental variable of the comparative observation position,
Evaluate reliability based on calculation results,
A release amount estimation program characterized by comparing the evaluated results and outputting the comparison results.

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