JPH0688873A - Method and device for evaluating distribution of radiation dosage rate - Google Patents

Abstract

PURPOSE:To quickly measure and evaluate the distribution of radiation dosage rates in a working space which is in a radiation environment and in which a radiation source changes. CONSTITUTION:By installing radiation detectors 2 around equipment 7 which is a radiation source, the radiation distribution caused by the equipment 7 is measured with the detectors 2. The radiation distribution and the data regarding the structure, material, etc., of the detectors 2 installed to the location for evaluating the distribution of radiation dosage rates are read out from a storage device 5 and, even when the constitution of the equipment 7 changes due to demolition, etc., a signal processor 4 calculates and evaluates the distribution of radiation dosage rates and outputs the calculated and evaluates results through an output device 6 in the form of an output diagram 601. Therefore, the distribution of radiation dosage rates can be evaluated with high accuracy, since the configuration in the working space can be taken into account at the time of measuring and evaluating the radiation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation dose rate distribution evaluation method and apparatus for radiation control of a nuclear facility, and particularly to a change in the radiation dose rate distribution due to the progress of dismantling of a nuclear facility. The present invention relates to a radiation dose rate distribution evaluation method and apparatus capable of performing quick and highly accurate evaluation.

[0002]

2. Description of the Related Art For example, in a nuclear power plant, work such as decontamination of nuclear reactor equipment and demolition of building concrete occurs with the dismantling of a decommissioned reactor. Most of these operations are in a radiation environment field, and it is necessary to plan a work process that optimizes the radiation exposure of workers and the cost of dismantling the decommissioning furnace. In order to plan this work process, it is necessary to obtain an accurate radiation dose rate distribution at the work place quickly and with high accuracy.

Conventionally, as a device for measuring the radiation dose rate distribution at the work site of a nuclear facility, there is, for example, the one described in JP-A-60-165570. In this conventional technique, the correlation between the radiation source intensity at the measurement target evaluation point and the radiation dose rate caused by the radiation source is obtained in advance, the radiation source intensity is calculated from the radiation dose rate measurement value, and this calculation result The radiation dose rate distribution is evaluated based on the shielding data.

[0004]

In the above-mentioned conventional technique, the radiation dose rate distribution is obtained by previously obtaining the correlation between the radiation source intensity and the radiation dose rate caused by the radiation source. This presupposes that the equipment configuration of the radiation source does not change. In other words, it is premised on the case of periodic inspections of nuclear power plants, and is suitable for evaluating work sites where the radiation dose rate distribution changes little. Therefore,
An accurate radiation dose rate distribution can be obtained even when applied to a location where the composition of the radiation source changes drastically with the progress of demolition and the attenuation / scattering amount of radiation fluctuates as the demolition progresses. There is a problem that you can not. Also, since a radiation dose rate meter is used for the radiation detector, when the nuclide intensity ratio of the radiation source in the equipment changes, the correlation between the radiation source intensity and the radiation dose rate due to the radiation source changes. Another problem is that That is, since the correlation is different from the correlation obtained in advance, an accurate radiation dose rate distribution cannot be obtained.

A first object of the present invention is to rapidly measure and evaluate the radiation dose rate distribution of a work place that constitutes equipment including a radiation source, along with the decommissioning of a nuclear power plant decommissioning furnace, and The object of the present invention is to provide a radiation dose rate distribution evaluation method and apparatus capable of obtaining an accurate radiation dose rate distribution even when the intensity ratio of the nuclide of the radiation source in the device changes.

A second object of the present invention is to provide a method and apparatus for planning / supporting a decommissioning work process, which optimizes the radiation dose and demolition cost of a demolition workman from the radiation dose rate distribution. To provide.

[0007]

The first object is to monitor the nuclide inventory in the equipment by the first means, monitor the dose rate of the equipment by the second means, and monitor these results.
This is achieved by obtaining the radiation dose rate distribution for each equipment configuration change from a database (third means) that stores plant information such as the structure, shape, and material of the equipment of the nuclear facility.

The above-mentioned second object is achieved by the fourth means having a database of the radiation dose rate distribution, which is the result obtained by the invention for achieving the first object, and the work contents in decommissioning the decommissioning nuclear facility. This is achieved by planning and supporting the work process.

[0009]

The amount of radiation shielding / scattering by a device changes depending on the density distribution of the structure and material of the device and the radioactivity intensity and distribution of nuclides present in the device. Therefore, in order to accurately obtain the radiation dose rate distribution, the radioactivity intensity and nuclides existing in the equipment are grasped, and the radiation shielding / scattering amount due to the equipment structure and material is identified for each radioactivity nuclide. There is a need to.

In the present invention, the first means simultaneously determines the type and intensity of radioactivity. That is, the radiation energy distribution is measured. For example, the first means is arranged around the device. Currently, the design of nuclear facilities is performed by a computer, and various information such as the structure and material of the equipment installed in the nuclear facility is stored in the computer as a database. Therefore, using this database (third means), the radiation dose rate distribution is obtained for each device configuration change.

The radioactivity intensity existing in the equipment is measured for each nuclide, and a response function Rij based on the radiation absorption distribution of the equipment with respect to the nuclide is obtained from plant information such as the shape, structure and material of the equipment. From the radiation count rate distribution Ci of the nuclide obtained by measurement,

[0012]

[Equation 5]

The radioactivity distribution Aj existing in the equipment is evaluated by. In addition, the radiation dose rate distribution Di is the radioactivity distribution Aj
And the response function R′ij obtained by removing the information on the measurement efficiency from the response function Rij and the dose rate conversion coefficient α,

[0014]

[Equation 6]

It can be obtained by

The first to measure the nuclide inventory in the equipment
The means is generally large-scale equipment, and if all of the means are arranged around the equipment of the nuclear facility, the equipment cost and installation time increase significantly. In order to avoid this problem, a second means for measuring the dose rate is installed around the device. This second means is not capable of discriminating and measuring the energy of radiation, but between the first and second means,
The following expression 7 holds.

[0017]

[Equation 7]

Further, it is possible to evaluate the type and intensity of radioactivity obtained by the first means from the result obtained by the second means by using the fact that the nuclide intensity ratios in the equipment of one system are almost equal. Become. That is, the number of the first means arranged around the equipment of each system of the nuclear facility can be reduced, and the first object can be achieved with a simple device configuration.

Next, how to obtain the response function Rij will be described. Radiation includes α, β, γ, X-rays and neutron rays. Generally, non-destructive and measurable are γ rays and X rays. As a method of evaluating the response function Rij in this γ-ray, for example, the equipment group is divided into several minute volumes, each of which is regarded as a point source, and the attenuation of the radioactivity is exponential attenuation and the inverse square of the distance. There is a method of evaluating by attenuation and approximating the amount of scattering by a build-up factor (point attenuation nuclear integration method). When γ-rays of energy E are emitted from the minute element of volume dv, the response function dR from dv at an arbitrary point is evaluated by the following expression 8.

[0020]

[Equation 8]

The response function Rij can be obtained by integrating this with respect to all the minute elements. From the above, the first object can be achieved with a simple device configuration.

Next, the fourth means will be described. The external exposure of workers at nuclear facilities can be evaluated by the radiation dose rate distribution at the work site, work time, work content, and work method. In addition, since the radiation dose and working time of nuclear facilities are regulated by law, it is possible to plan and support an optimized work process based on work costs if the radiation dose of workers is obtained in advance. Become. Therefore, by linking a database related to radiation work such as work content and work method with the radiation dose rate distribution data of the work place of the nuclear facility obtained by the first to third means, the dose rate, exposure dose, and work cost are optimized. By solving the optimization problem, it is possible to plan and support this work process.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. First, the overall configuration and operation of a radiation dose rate distribution measuring (evaluating) apparatus according to an embodiment of the present invention will be described.

FIG. 1 is a conceptual diagram of a radiation dose rate distribution measuring (evaluating) device. A radiation detector 2 (shown by ●) is two-dimensionally arranged around a device 7 which can be a radiation source which is one of the influencing factors of the radiation dose rate distribution in the radiation dose rate distribution evaluation place 1 in a nuclear facility. A plurality (eight in the illustrated example) are arranged. A plurality of radiation detectors 2 are thus arranged around the device 7 to detect the radiation emitted from the device 7 which is a radiation source. The radiation signal detected by the radiation detector 2 is transmitted to the signal processing device 4 by the signal transmitter 3.

The signal processing device 4 evaluates and identifies the radioactivity intensity and the nuclide existing in the equipment 7, and from the magnetic storage device 5 connected to the signal processing device 4, the radiation dose rate distribution evaluation place of the nuclear facility. The data of the structure, material, arrangement, etc. of the equipment 7 existing in 1 is called, the attenuation / scattering amount of radiation in the equipment 7 is evaluated for each nuclide, and the radiation for each nuclide existing in the equipment 7 obtained previously is evaluated. The radiation dose rate distribution at the radiation dose rate distribution evaluation place 1 is obtained by performing a calculation evaluation together with the activity intensity.

The arithmetic processing method will be described later. The radiation dose rate distribution obtained here is colorized according to intensity, overwritten on the cross-sectional view of the constituent devices in the dose rate distribution evaluation place 1, and output by the output device 6 on a screen or as a drawing. An output example 601 of the output device 6 is shown together with FIG.

In general, the radiation dose rate distribution is defined as the γ-ray energy emitted by the radiation source, the intensity of the radiation source and the distribution shape of the radiation source,
Interaction between radiation source and radiation detector (radiation shielding,
Attenuation, scattering). A method of measuring and a method of evaluating the factors that determine the radiation dose rate will be described with reference to FIGS. 2 and 3.

FIG. 2 is a block diagram of the radiation dose rate distribution measuring (evaluating) apparatus according to this embodiment (detailed configuration diagram of the signal processing apparatus shown in FIG. 1). The signal processing apparatus 4 outputs the radiation detection signal. The measuring instruments 8 and 9 for processing and the arithmetic processing unit 4a for arithmetically processing the measurement result.

The radiation dose rate distribution evaluation place 1 has a radioactive substance (not shown) inside the device 7 which affects the radiation dose rate distribution. This radioactive material emits radiation. Radiation detectors 201 and 202 arranged around the device 7 measure the radiation transmitted through the device 7. The radiation that can penetrate a substance such as the device 7 is γ-ray.

The radiation detector 201 is capable of simultaneously measuring the type and intensity of radioactivity, and NaI
A (Tl) scintillation detector, a high-purity Ge semiconductor detector, or the like can be used. On the other hand, the radiation detector 20
2 is for measuring the dose rate, and an ionization chamber, a PN junction type Si semiconductor detector or the like can be used. Detector 20
A collimator 10 that removes radiation from outside the measurement region, that is, radiation that interferes (background radiation) is disposed at 1. Although the background radiation is deleted also in the detector 202, although illustration is omitted,
A similar collimator is provided.

The γ-ray emitted from the device 7 is the radiation detector 2
01, the detection signal is input to the γ-ray energy distribution measuring device 8 by the signal transmitter 3 shown in FIG.
The line energy distribution measuring device 8 obtains the γ-ray energy distribution in the region where the radiation detector 201 in the device 7 is expected. This γ-ray energy distribution is a count value distribution for γ-ray energy, and γ-ray emitting nuclides emit γ-rays of a fixed energy for each nuclide, so by analyzing this γ-ray energy distribution Can be identified.

An example of the method of analyzing the γ-ray energy distribution will be shown below. The γ-ray energy distribution measuring device 8 has a data storage address corresponding to the γ-ray energy, and the radiation dose (count value) of the γ-ray energy corresponding to the data storage address is stored. That is, if the number of count values, which is the content of the data storage address, is superior to the statistical fluctuation, it means that the γ-ray energy of the data storage address is measured.
Therefore, a table of the γ-ray energy emitted by the radiation source is prepared for each radiation source, and the nuclide can be identified by determining the presence or absence of the count value of the contents of the data storage address with respect to the contents of the γ-ray table. The intensity can be known from the count value.

The γ rays emitted from the device 7 are also detected by the radiation detector 202. The detection signal is similarly input to the γ-ray gross count value measuring device 9 by the signal transmitter 3, and the γ-ray gross count value measuring device 9 detects the γ-rays in the region expected by the radiation detector 202 in the device 7. Get the gross count. The surface dose rate of the device 7 can be obtained by multiplying the gamma ray gross count value by the dose rate conversion coefficient of the radiation detection 202. Further, the radiation detector 201 and the radiation detector 202
The following relational expression 9 is established during the period.

[0034]

[Equation 9]

In addition to the above relationship being established, it is assumed that the nuclide intensity ratios in the equipment of one system are almost equal. That is, if the structure and material of the equipment of one system are the same at different measurement locations, the shapes of the measured radioactivity distributions will be similar. This means that the height of the radioactivity distribution is entirely changed according to the dose rate, and the radiation detector 20
From the result obtained in 2, it is possible to evaluate the type and intensity of radioactivity obtained by the radiation detector 201. That is, the number of the radiation detectors 201, which are expensive and large-scale measuring instruments, can be reduced, and the system configuration becomes simple.

The shape of the radioactive substance existing in the device 7 causes an error in the above radiation measurement. However, the equipment 7 of the nuclear facility has an overwhelmingly large number of cylindrical pipe groups, most of the radioactive materials are distributed in a plane on the inner surface of the equipment 7, and
Since it can be assumed that the minute regions expected by the radiation detectors 201 and 202 are uniform, the error due to the shape of the radioactive substance can be ignored.

When the output information of the γ-ray energy distribution measuring instrument 8 and the γ-ray gross count measuring instrument 9 obtained by the above method is passed to the arithmetic processing section 4a, the arithmetic processing section 4a will detect the radioactivity in the equipment 7. Radiation dose rate distribution evaluation place 1 by image processing from nuclear type intensity and surface dose rate data and plant information such as equipment 7 of a nuclear facility held in the magnetic storage device 5 connected to the signal processing device 4. In addition to creating a cross-sectional view of the device configuration inside, the radiation dose rate distribution in the radiation dose rate distribution evaluation location 1 is obtained by performing arithmetic processing using the method described below, and the radiation dose rate distribution is displayed on the cross-sectional view of the device configuration. Overwriting is performed, and the result is output from the output device 6.

Next, the method of evaluating the radiation dose rate distribution and the work process will be described with reference to FIG. FIG. 3 is a flowchart showing the evaluation procedure. The nuclide of the radioactive substance existing inside the device 7 can be known by the method of referring to the nuclide table of the γ-ray energy distribution measuring instrument 8 described above. However, the amount of radioactivity (intensity) existing inside the device 7
In order to quantify the number of nuclei, it is necessary to know the structure and material of the device 7. This is because when the γ-ray passes through the device 7, the amount of transmission and the amount of scattering change depending on the structure and material of the device 7. In order to accurately grasp the transmission amount and the scattering amount, in this embodiment, the amount determined by the counting efficiency and geometric efficiency of the radiation detector 201, the γ-ray energy emitted by the nuclide, and the structure and material of the device 7 is used. Evaluate a certain response function Rij. This is performed by extracting the structure / material of the device 7 from a database (magnetic storage device 5) of design drawings and the like and calculating it by the arithmetic processing unit 4a. How to obtain the response function Rij will be described below.

Radiation includes α, β, γ, X-rays and neutron rays. Generally, non-destructive and measurable are γ rays and X rays. As a method of evaluating the response function Rij in this γ-ray, for example, the equipment group is divided into several minute volumes, each of which is regarded as a point source, and the attenuation of the radioactivity is exponential attenuation and the inverse square attenuation of distance. There is also a method (point-decay kernel integral method) that evaluates with and approximates the amount of scattering with a build-up factor. When γ-rays of energy E are emitted from the minute element of volume dv, the response function dR from dv at an arbitrary point is evaluated by the following expression 10.

[0040]

[Equation 10]

The response function Rij can be obtained by integrating this with respect to all the minute elements. That is, the structure and material information of the device 7 group is called from the magnetic storage device 5, the device 7 group is divided into meshes, and the above-mentioned arithmetic processing is performed on each mesh (step 1 in FIG. 3). Further, in the actual calculation, it is necessary to divide (i, j) the space through which γ-rays are transmitted, further divide the radiation source into a large number of radiation source elements, and implement the discretization of γ-ray energy.

Therefore, the γ-rays emitted from the equipment 7 are measured around the equipment 7, and the γ-ray energy distribution measuring device 8 obtains the count values of the γ-ray energy (E) and the γ-rays (E) to obtain the γ-rays. By dividing the count value of (E) by the measurement time to obtain the count rate distribution Ci of γ-rays (E) (step 2), the following equation 11

[0043]

[Equation 11]

There is a relation of (2), and by performing the inverse matrix calculation of this equation 11, the radioactivity distribution Aj in the equipment 7 can be obtained (step 3).

The radiation dose rate distribution Di in the radiation dose rate distribution evaluation place 1 is the activity distribution Aj existing in the device 7.
Therefore, the radiation dose rate distribution Di can be obtained by the following equation 12 as in the above calculation method.

[0046]

[Equation 12]

Compared with the response function Rij of the above equation 5,
The difference of the response function R'ij in Expression 6 is only that the measurement efficiency of the radiation detector including the geometric efficiency, which is a factor in radiation measurement, is not included. The influence of this measurement efficiency can be evaluated by the characteristics of the radiation detector used, the shape of the collimator 10 and the installation state of the radiation detector 2 in the device 7. Since these factors are eigenvalues in terms of hardware in radiation measurement, the measurement efficiency can be obtained in advance. From the above, the radiation dose rate distribution can be obtained by measuring the radioactivity intensity of the device 7 (step 4).

Next, a method of evaluating the work process will be described. The external exposure of workers is defined as the product of absorbed dose, quality factor and correction factor. Since the quality factor and the correction factor for γ-rays are constant, it is possible to obtain the dose of the worker by evaluating the absorbed dose. Furthermore, this absorbed dose can be approximately represented by the product of the radiation dose rate at the work place and the work time at that place. That is, the radiation dose of a worker who works in a nuclear facility can be determined by the radiation dose rate of the work place, the work time, the work content, and the work method. Further, the work time and exposure dose of the work in the nuclear facility are regulated by law. For example, the work time is within 10 hours, the exposure dose is 0.15 Sv / year for the eye lens, and 0 for tissues other than the lens. For example, 5 Sv / year. Therefore, if the exposure dose of the worker can be estimated in advance, it is possible to plan an optimized work process including work cost and the like. The contents will be described below.

In the case of a nuclear power plant, the equipment is inspected (periodic inspection) at regular intervals, and it has a database of the operations related to the periodic inspection (work contents, work method, work time, etc.). That is, as long as the work content is determined, it is easy to obtain the work place, work time, and the like. Here, by linking the radiation dose rate distribution data obtained by the above-mentioned method with the work database, the exposure dose of the worker can be evaluated. From the above, the work process can be optimized by solving the problem of optimization of the exposure dose, period and cost with the signal processing device. The work method for dismantling the decommissioning facility at a nuclear facility is an extension of the method for regular inspections, and it is assumed that most work databases are available, so the work process can be optimized even when dismantling the decommissioning plant (steps in Fig. 3). 5).

As described above, since the present invention comprises a simple radioactivity measuring device and a signal processing device such as a computer, the radiation dose rate distribution evaluation place 1
Even if the configuration of the device 7 group in the inside changes, the change information of the device 7 group is input to the database of the plant of the magnetic storage device 5 of the signal processing device 4 by an input means such as a keyboard,
By updating the database, it is possible to easily and accurately cope with the decommissioning of a nuclear power facility whose equipment configuration is changing. Further, since the radiation detector 2 continuously monitors the radiation and the response function Rij is evaluated every time,
The radiation dose rate distribution can be refreshed in a short time,
Even when the radiation dose rate changes drastically like the decommissioning of a nuclear facility, the work process can be supported and corrected quickly.

Furthermore, when dismantling a nuclear facility,
Decontaminate the radioactive substances adhering to the equipment. In this decontamination work, various decontamination methods are used in order to reduce the amount of radioactive waste generated and the cost of waste disposal.
Therefore, it is necessary to accurately evaluate the decontamination effect. Therefore, in the present invention, the γ ray emitted from the device 7 is used as the radiation detector 2
The radioactivity intensity and nuclide existing in the equipment 7 are measured by the signal processing device 4 at a fixed time interval or before and after the start of the decontamination work, and the decontamination effect is accurately evaluated by evaluating the rate of change. can get. If this decontamination effect can be evaluated, the decontamination liquid used for the subsequent decontamination, the decontamination time, etc. can be estimated, and a secondary effect called planning of decontamination work can be obtained.

In the above embodiment, the radiation detector 2 is provided with the collimator 1 in order to remove the influence of background radiation.
0 is set. However, since the normal radiation detector 201 is large, the collimator that shields it is large and heavy, and it is difficult to mount it. Therefore, as shown in FIG.
The movable shutter 11 is provided in front of the radiation detector 201. By controlling the moving shutter 11 to move in the direction of the sin, the γ-rays emitted from the device 7 are moved by the moving shutter 11.
And the γ-ray intensity measured by the radiation detector 201 is sin-modulated (waveform b in FIG. 5). On the other hand, since the background radiation is incident on the radiation detector 201 with a constant intensity (a in FIG. 5), if the sin-modulated radiation signal as shown in FIG. Can be removed.

[0053]

EFFECTS OF THE INVENTION According to the present invention, it is possible to measure and evaluate radioactivity with a simple device configuration by grasping changes in the device configuration of a work place under the radiation environment of a nuclear facility, and to quickly calculate the radiation dose rate distribution. Moreover, it can be evaluated with high accuracy. In addition, it is possible to plan and support an optimized work process.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a radiation dose rate distribution evaluation apparatus according to an embodiment of the present invention.

FIG. 2 is a detailed configuration diagram of the signal processing device shown in FIG.

FIG. 3 is a flowchart showing a procedure for evaluating a radiation dose rate distribution.

FIG. 4 is a diagram showing an example of a modification of the installation state of the radiation detector.

FIG. 5 is a graph showing sin modulation of γ rays.

[Explanation of symbols]

1 ... Radiation dose rate distribution evaluation place, 2 ... Radiation detector, 3
... signal transmitter, 4 ... signal processing device, 4a ... arithmetic processing unit,
5 ... Magnetic storage device, 6 ... Output device, 7 ... Equipment, 8 ... γ-ray energy distribution measuring device, 9 ... γ-ray gloss count value measuring device, 1
0 ... Collimator, 11 ... Moving shutter.

Claims (12)

[Claims] 1. A method for measuring and evaluating a radiation dose rate distribution of a work place in a radiation environment, wherein a radiation absorption distribution of a nuclide with respect to a device existing in a radiation dose distribution measurement region and radiation emitted from the device itself. A radiation dose rate characterized by evaluating a radioactivity distribution based on a count rate distribution, and obtaining a radiation dose rate distribution by using a distribution obtained by removing information on measurement efficiency from the radiation absorption distribution and a dose rate conversion coefficient. Distribution evaluation method. 2. A method for measuring and evaluating a radiation dose rate distribution of a work place in a radiation environment, wherein a response function Rij based on a radiation absorption distribution of a nuclide in a device existing in a radiation dose distribution measurement region and the device itself. From the radiation count rate distribution Ci emitted from the From the response function R'ij obtained by evaluating the radioactivity distribution Aj from the above and removing the information regarding the measurement efficiency from the response function Rij and the dose rate conversion coefficient α, the following equation 2 A radiation dose rate distribution evaluation method, characterized by obtaining a radiation dose rate distribution Di from the above. 3. A method for measuring and evaluating a radiation dose rate distribution of a work place in a radiation environment, in which radiation caused by a device serving as a radiation source is measured to evaluate the radiation energy distribution, and the radiation energy distribution is calculated from the radiation energy distribution. The nuclide of the radioactivity Ai existing in the equipment is identified, and the response function Rij based on the radiation absorption distribution for each identified nuclide is determined from the plant data such as the structure, material, and shape of each equipment existing in the radiation dose distribution measurement region. A method for evaluating radiation dose rate distribution, characterized by obtaining. 4. The number of detectors for measuring radiation energy distribution is reduced by reducing the intensity ratios of nuclides existing in one-system equipment existing in the radiation dose distribution measurement region to be equal in claim 3. A radiation dose rate distribution evaluation method, characterized in that the radiation data for each minute is supplemented by a detector capable of measuring the dose rate. 5. A method for measuring and evaluating a radiation dose rate distribution of a work place under a radiation environment, wherein the radiation dose rate distribution Di obtained in claim 2 and data such as work contents in the radiation environment are measured. A work process evaluation method characterized by planning and supporting work processes. 6. A device for measuring and evaluating a radiation dose rate distribution in a work place under a radiation environment, wherein a response function Rij based on a radiation absorption distribution of a nuclide in a device existing in a radiation dose distribution measurement region and the device itself. Means for obtaining the radiation count rate distribution Ci emitted from Means for evaluating the radioactivity distribution Aj from the above, and the response function Ri
Response function R'i with information on measurement efficiency removed from j
Using j and the dose rate conversion coefficient α, the following equation 4 And a means for obtaining the radiation dose rate distribution Di from the radiation dose rate distribution evaluation apparatus. 7. A device for measuring and evaluating a radiation dose rate distribution of a work place in a radiation environment, a means for measuring radiation resulting from a device serving as a radiation source, and a radiation energy distribution thereof. Based on the means for identifying the nuclide of radioactivity Ai existing in the equipment from the distribution and the plant data such as the structure, material and shape of each equipment existing in the radiation dose distribution measurement area, based on the radiation absorption distribution for each identified nuclide A radiation dose rate distribution evaluation apparatus comprising: a means for obtaining a response function Rij. 8. The number of detectors for measuring radiation energy distribution is reduced by reducing the intensity ratios of nuclides existing in one-system equipment existing in the radiation dose distribution measurement region to be equal to each other. A radiation dose rate distribution evaluation device, comprising means for supplementing radiation data for a minute amount with a detector capable of measuring a dose rate. 9. An apparatus for measuring and evaluating a radiation dose rate distribution of a work place under a radiation environment, wherein the radiation dose rate distribution Di obtained in claim 6 and data such as work contents in the radiation environment are measured. A work process evaluation device characterized by planning and supporting work processes. 10. A method for evaluating a radiation dose rate distribution at a dismantling work place when a configuration of a radiation source changes as the reactor dismantling work progresses at the time of decommissioning a reactor Dose rate from the remaining radiation source equipment at the demolition work site after removing a certain radiation source equipment from the radiation detection data by the reactor and the pre-stored structural data of the equipment that constitutes the decommissioning target reactor A radiation dose rate distribution evaluation method characterized by calculating a distribution. 11. An apparatus for evaluating a radiation dose rate distribution at a dismantling work place when a radiation source equipment configuration changes as the reactor dismantling work progresses at the time of decommissioning a nuclear reactor, the radiation installed at the dismantling work place. Detector, the dismantling work place after removing a radiation source device from a database in which structural data of the devices constituting the reactor to be dismantled is stored in advance, and a detection signal of the radiation detector and accumulated data in the database The radiation dose rate distribution evaluation apparatus according to claim 1, further comprising: a calculation unit that calculates and obtains a radiation dose rate distribution by the remaining radiation source equipment. 12. A radiation dose rate distribution evaluation apparatus according to claim 11, and solving the problem of optimization of the radiation dose rate distribution by the radiation dose rate distribution evaluation apparatus and the exposure dose of workers, work period, and work cost. A reactor dismantling work planning / supporting device, comprising: