JP2022096115A - Radioactive contamination measuring system - Google Patents

Abstract

To provide a radioactive contamination measuring system capable of measuring accurately surface contamination of inspection objects with various surface shapes.SOLUTION: The radioactive contamination measuring system includes: a radiation detector assembly using two or more radiation detectors; a shape measurement unit that measures a surface shape of an object to be inspected; and a controller that executes determination processing whether or not an amount of surface contamination is within a permissible value of a detection result. Each of the radiation detectors includes multiple sensitive planes and a drive system that can move independently. The controller executes a positioning control for each of the radiation detectors so that a distance from the surface shape is within an allowable distance range, and after completing the positioning control, executes the determination processing based on the detection results acquired from each of the radiation detectors.SELECTED DRAWING: Figure 7

Description

The present disclosure relates to an apparatus for measuring surface contamination of inspection objects having different shapes with high accuracy, and particularly to an apparatus for measuring radioactive contamination using a plurality of radiation detectors.

There is a prior art technique using a plurality of radiation detectors for detecting surface contamination by radioactive substances of an inspection object (see, for example, Patent Document 1). In the radiation detector according to Patent Document 1, a plurality of scintillator blocks having the same configuration (material, shape, size, etc.) are laminated to form a three-dimensional laminated scintillator, and a configuration excellent in mass productivity is realized.

In the three-dimensional arrangement in Patent Document 1, a plurality of scintillator blocks are laminated in the height direction (z direction) in order to specify the incident position of radiation, and are arranged in a straight line in the z direction. Further, it has a configuration in which a plurality of scintillator blocks arranged in a straight line in the z direction are arranged in parallel in the x direction and the y direction.

As a result, the radiation detector in Patent Document 1 is excellent in position decomposition performance in the depth direction (z direction).

Japanese Unexamined Patent Publication No. 2013-140024

However, the prior art has the following problems.
According to the Ionizing Radioactivity Hazard Prevention Regulations, when handling radiation whose dose rate at the boundary of the site exceeds a certain value, a controlled area should be set up and an inspection for contamination by radiation should be performed when the goods are taken out of the controlled area. Is stipulated. Therefore, radioactive contamination measuring devices are used in nuclear facilities.

Consider the case where the radiation detector according to Patent Document 1 is used as the radioactive contamination measuring device. In this case, the detection accuracy should be improved for the inspection target having a certain distance from the radiation detector, that is, for the sensitive surface of the radiation detector in the xy plane and for the flat detection target. Is possible.

However, as articles to be taken out from the controlled area, long objects such as ladders, scaffolding materials, and scaffolding pipes are also objects to be inspected, and the surface shape is not always flat. Therefore, for an inspection object having various surface shapes that are not flat, in a radiation detector having a fixed shape of the detector sensitive surface as in Patent Document 1, the inspection object has a radiation detector sensitive surface. It was difficult to get close to it, and it was difficult to measure the surface contamination of the inspection object with high accuracy.

The present disclosure has been made to solve the above-mentioned problems, and is a radioactive contamination measuring device capable of measuring the surface contamination of an inspection object having various surface shapes with high accuracy and speed. The purpose is to get.

The radioactive contamination measuring device according to the present disclosure includes a radiation detector aggregate using two or more radiation detectors for detecting the amount of surface contamination of the inspection object by radioactive substances, and a shape for measuring the surface shape of the inspection object. Each of the radiation detectors is equipped with a measuring unit and a controller that executes a determination process of whether or not the surface contamination amount is within the permissible value from the detection results of the radiation detectors, and each of the radiation detectors has a plurality of sensitive surfaces. In addition to having, it has a drive system that can move independently in the same movement axis direction common to all radiation detectors, and the controller has a drive system that can move independently from the surface shape based on the measurement result by the shape measurement unit. Positioning control is executed for each of the radiation detectors via the drive system so that the distance between the two is within the allowable distance range, and based on the detection results obtained from each of the radiation detectors after the positioning control is completed. It executes the determination process.

According to the present disclosure, it is possible to obtain a radioactive contamination measuring device capable of measuring surface contamination of an inspection object having various surface shapes with high accuracy and speed.

It is explanatory drawing which showed the schematic shape of the radiation detector in Embodiment 1 of this disclosure. It is explanatory drawing about the inspection in the case of using one radiation detector in Embodiment 1 of this disclosure. In Embodiment 1 of this disclosure, it is explanatory drawing concerning the inspection in the case where the radiation detectors shown in FIG. 1 (b) are arranged in a matrix. It is a figure which showed three configuration examples which arranged a plurality of radiation detectors which concerns on Embodiment 1 of this disclosure. It is a figure which showed two inspection methods in the case of arranging a plurality of radiation detectors in a matrix in Embodiment 1 of this disclosure. It is explanatory drawing which showed the specific structure about one radiation detector in Embodiment 1 of this disclosure. It is a figure for demonstrating the whole structure of the radioactive contamination measuring apparatus of this disclosure. It is explanatory drawing which shows typically the series process by the radioactive contamination measuring apparatus which concerns on Embodiment 1 of this disclosure. It is explanatory drawing which summarized the series procedure which quantitatively obtains the surface contamination state by the radioactive substance of the inspection object by the radioactive contamination measuring apparatus in Embodiment 1 of this disclosure. It is a conceptual diagram which shows the driving state of each of the plurality of radiation detectors in Embodiment 1 of this disclosure.

Hereinafter, preferred embodiments of the radioactive contamination measuring apparatus of the present disclosure will be described with reference to the drawings.

Embodiment 1.
First, the features that the radioactive contamination measuring apparatus according to the present disclosure should have will be described.
If the object to be inspected is a simple lump shape, it is possible to inspect the entire surface of the object to be inspected by bringing the radiation detector close to the top, bottom, left, right, front and back. However, many inspection objects taken out of the controlled area are not limited to a lump shape, but have a shape having an inner surface such as a U shape.

Further, in order to bring the radiation detector close not only to the upper surface but also to both side surfaces and the front and rear surfaces, it is necessary to install the radiation detection device on both side surfaces and the front and back surfaces. Therefore, the examination results are summarized below regarding the structure and inspection method of the radiation detector that can quickly inspect the entire surface of the object to be inspected except the bottom surface.

(1) Structure of Radiation Detector FIG. 1 is an explanatory diagram showing a schematic shape of the radiation detector according to the first embodiment of the present disclosure. Specifically, FIG. 1A shows a schematic shape of the current plastic scintillation detector, which is a general radiation detector 110. Further, FIG. 1B shows a schematic shape of a radiation detector having a three-dimensional sensation surface, which is the radiation detector 10 according to the first embodiment.

As shown in FIG. 1A, the sensitive surface 111 of a general radiation detector 110 is a simple two-dimensional plane. In order to inspect the entire surface of the object to be inspected by the radiation detector 110 having one sensory surface 111, the radiation detector 110 is to be inspected from a plurality of directions (usually, six directions of up and down, left and right, and front and back). It is necessary to get close to things.

In order to realize such an operation, a plurality of driving devices and an articulated robot for moving the radiation detector 110 are required. However, as the number of drive devices increases, the device becomes large, and even if several articulated robots are used, if the surface shape of the object to be inspected is complicated, it takes a lot of time to scan the entire surface. It takes and is not realistic.

As a solution to this, the radiation detector 10 according to the first embodiment has a schematic shape as shown in FIG. 1 (b). Specifically, a three-dimensional structure is adopted in which the five surfaces of the rectangular parallelepiped radiation detector 10 are the sensitive surfaces 11. As a result, by bringing the radiation detector 10 close to the shape of the inspection object from one direction, the radiation detector 10 does not change its direction, and there are five sensitive surfaces on all surfaces except the bottom surface of the inspection object. 11 can be brought closer.

(2) Inspection method By using the radiation detector 10 having the sensitive surface 11 of the three-dimensional structure, it is possible to simultaneously inspect a plurality of surfaces. FIG. 2 is an explanatory diagram regarding an inspection when one radiation detector 10 is used in the first embodiment of the present disclosure. FIG. 2 illustrates a case where the inspection object 1 has an L-shape. In this case, the radiation detector 10 simultaneously inspects two surfaces of the L-shaped inspection object 1 by using the sensation surface 11 provided on the bottom surface and the sensation surface 11 provided on the left side surface. be able to.

Next, FIG. 3 is an explanatory diagram regarding an inspection when the radiation detectors 10 shown in FIG. 1 (b) are arranged in a matrix in the first embodiment of the present disclosure. FIG. 3 shows a cross section in which the surface of the object to be inspected 1 has a complicated shape and the surface of the object to be inspected is inspected by the radiation detectors 10 arranged in a matrix. The radiation detectors 10 arranged in a matrix are shown as a radiation detector assembly 100.

As shown in FIG. 3, a large number of radiation detectors 10 are arranged in a matrix, and the radiation detector 10 is moved (inserted) to an appropriate position according to the shape of the inspection object 1 to move (insert) the radiation detector 10. Can be quickly inspected on both the inner surface and the outer surface of the inspection object 1 without scanning along the surface of the inspection object 1. In FIG. 3, the arrow D1 shown as the direction of the double-headed arrow corresponds to the same moving axis direction common to all the radiation detectors 10.

FIG. 4 is a diagram showing three configuration examples in which a plurality of radiation detectors 10 according to the first embodiment of the present disclosure are arranged. FIGS. 4 (a) to 4 (c) show the following configurations, respectively. In FIG. 4, in the three-dimensional space defined by the X-axis, the Y-axis, and the Z-axis orthogonal to each other, the radiation detector is assumed to have the same movement axis direction for all the radiation detectors 10 as the Z-axis direction. 10 exemplifies the case where 10s are arranged in a matrix in the XY plane defined by the X-axis and the Y-axis.

FIG. 4 (a): Radiation detectors 10 are arranged in a matrix and the inspection object 1 is inspected at one time. FIG. 4 (b): Radiation detectors 10 are arranged in a matrix and divided into two or more times to perform radiation. Configuration for inspecting the inspection target 1 while moving the detector 10 FIG. 4 (c): Radiation detectors 10 are arranged in a row, divided into rows, and the inspection target 1 is inspected while the radiation detector 10 is moved. Configuration to be

In any configuration, with the plurality of radiation detectors 10 stopped, each radiation detector 10 is moved in the z direction according to the surface shape of the object 1 to be inspected, and one measurement is performed. Then, in the configuration of FIG. 4B or FIG. 4C, in order to perform the second and subsequent inspections, the plurality of radiation detectors 10 are moved to the initial positions and then moved to the next inspection position. The operation of moving each radiation detector 10 in the z direction according to the surface shape of the inspection object 1 is repeated as many times as necessary.

The larger the number of radiation detectors 10, the shorter the inspection time, but the higher the cost. Therefore, the optimum arrangement configuration of the radiation detector 10 is selected from the viewpoint of cost-performance according to the size of the inspection object 1, the number of inspections, and the like.

FIG. 5 is a diagram showing two inspection methods in the case where a plurality of radiation detectors 10 are arranged in a matrix in the first embodiment of the present disclosure. FIGS. 5 (a) and 5 (b) show the following inspection methods, respectively.
FIG. 5A: An inspection method in which small radiation detectors 10 are arranged in a matrix and each detector is counted independently (hereinafter referred to as inspection method 1).
FIG. 5 (b): An inspection method in which small radiation detectors 10 are arranged in a matrix, two or more adjacent detectors are grouped, and the counts for each group are added by an addition amplifier 101 (hereinafter, inspection method). 2)

When the inspection method 2 is adopted, the resolution of the contamination site detection is lower than that of the inspection method 1, but the inspection time is faster than that of the inspection method 1 by using the addition result. It will be possible to change. Therefore, an appropriate inspection method is selected according to the inspection resolution and inspection speed required for the inspection object 1.

Next, a configuration of a small radiation detector 10 adopted in the first embodiment, and a specific configuration of a radioactive contamination measuring device configured as a radiation detector assembly 100 using a plurality of radiation detectors 10. The function will be described in detail with reference to the drawings.

FIG. 6 is an explanatory diagram showing a specific configuration of one radiation detector 10 according to the first embodiment of the present disclosure. One radiation detector 10 shown in FIG. 6 includes a sensitive surface 11, a bumper sensor 12, a distance sensor 13, and a signal processing unit 14, and the drive guide 15 is driven to move up and down in the z direction. It is a possible configuration.

The sensory surface 11 is provided on a total of five surfaces, four side surfaces and a bottom surface of the detector body having a rectangular parallelepiped shape. The bumper sensor 12 is a sensor that outputs as an ON / OFF signal whether or not the distance to the inspection object 1 is within a preset distance. The distance sensor 13 is a sensor that outputs the distance to the inspection object 1 as an analog value.

The signal processing unit 14 is provided on the upper surface of the detector main body, receives the total amount of signals detected by the sensory surfaces provided on the five surfaces via photomultiplier tubes (not shown), and converts them into optical signals. And output.

In the matrix-shaped radiation detector 10 in the present disclosure, a plurality of radiation detectors 10 are integrated by arranging one radiation detector 10 shown in FIG. 6 in a matrix shape to form a radiation detector assembly 100. It is configured so that each radiation detector 10 can move up and down individually in the z direction. Here, the z direction corresponds to the same moving axis direction common to all the radiation detectors 10.

FIG. 7 is a diagram for explaining the overall configuration of the radioactive contamination measuring apparatus of the present disclosure. As shown in FIG. 1, the radioactive contamination measuring device according to the first embodiment is configured to include a plurality of radiation detectors 10, a driving unit 20, a shape measuring unit 30, a controller 40, and a transport mechanism 50. There is.

Each configuration of FIG. 7 will be described.
The shape measuring unit 30 measures the surface shape of the inspection object 1 which is the object of measuring the amount of radioactive contamination. The shape measuring unit 30 can measure various surface shapes by using a known three-dimensional shape recognition method.

Specific examples of the three-dimensional shape recognition method include the following.
<Method 1: TOF (Time of Flight) method>
In method 1, the distance to the inspection object 1 is calculated by irradiating the inspection object 1 with a laser pulse, measuring the time until the reflected light returns from the inspection object 1, and multiplying the measured time by the speed of light. It is something to recognize.

<Method 2: Optical cutting method (triangulation method)>
Method 2 irradiates the inspection object 1 with a line laser and recognizes the position of the inspection object 1 by the principle of triangulation based on the position where the reflected light is formed from the inspection object 1.

<Method 3: Image processing (pattern projection method)>
In the method 3, a striped pattern is projected onto the inspection object 1, the state of each projected stripe is imaged by four cameras, and the amount of deformation of the striped pattern deformed by the surface shape of the inspection object 1 is used. The three-dimensional shape of the inspection object 1 is obtained.

<Method 4: Image processing (stereo camera)>
In the method 4, the inspection object 1 is photographed by two cameras having the same focal length, and the distance to the inspection object is recognized by the parallax of the two captured images.

Therefore, the shape measuring unit 30 can measure the surface shape of the inspection object 1 from the recognition result (measurement result) by any one of the methods 1 to 4 or the combination of a plurality of recognition results (measurement results). ..

The controller 40 can output a measurement command for measuring the surface shape of the inspection object 1 to the shape measuring unit 30, and can receive the surface shape measured by the shape measuring unit 30 as a response. ..

The drive unit 20 drives the plurality of radiation detectors 10 in the z direction by driving the drive guides 15 provided on the plurality of radiation detectors 10 based on the movement command from the controller 40.

The controller 40 outputs a measurement command to each radiation detector 10 that has completed the movement according to the surface shape of the inspection object 1, and receives the detection result as a response. Then, the controller 40 quantitatively determines the amount of surface contamination of the inspection object 1 by the radioactive substance based on the detection results obtained from the plurality of radiation detectors 10. That is, the controller 40 executes a determination process of whether or not the surface contamination amount is within the permissible value from the detection results obtained from each of the radiation detectors.

FIG. 8 is an explanatory diagram schematically showing a series of treatments by the radioactive contamination measuring apparatus according to the first embodiment of the present disclosure. As shown in FIG. 8, the controller 40 can move the inspection object 1 to the shape measurement area Z1 and the inspection area Z2 by driving the transport mechanism 50. Although the inspection object 1 is moved in the direction of the arrow D2 in FIG. 8, it is also possible to set the shape measurement area Z1 and the inspection area Z2 as overlapping areas.

First, the controller 40 conveys the inspection object 1 to the shape measurement area Z1, outputs a measurement command to the shape measurement unit 30, and in response, outputs the surface shape data specified by the shape measurement unit 30. Receive.

Next, the controller 40 conveys the inspection object 1 whose surface shape has been specified to the inspection area Z2. Further, the controller 40 uses a plurality of radiation detectors 10 to quantitatively determine the amount of surface contamination of the inspection object 1 by the radioactive substance.

FIG. 9 is an explanatory diagram summarizing a series of procedures for quantitatively determining the surface contamination state of the inspection object by the radioactive contamination measuring device according to the first embodiment of the present disclosure. FIG. 1 shows a series of processes after the inspection object 1 has been moved to the inspection area Z2. Further, each figure in step 1, step 2, and step 4 of FIG. 1 shows a cross-sectional view.

In step 1, the controller 40 stops each of the plurality of radiation detectors 10 at a desired position close to the surface shape of the inspection object 1 based on the surface shape data received from the shape measuring unit 30. Calculate the target position in the z direction. Further, the controller 40 outputs a movement command to the drive unit 20 to bring the radiation detector assembly 100 including the plurality of radiation detectors 10 closer to the inspection object 1 as a whole.

In step 2, the controller 40 further moves each of the plurality of radiation detectors 10 individually toward the target position and stops them within an allowable distance range. At this time, the controller 40 utilizes the detection results of the bumper sensor 12 and the distance sensor 13 shown in FIG. 6 to perform positioning control for stopping each radiation detector 10 within the allowable distance range. It can be carried out. As a result, each of the plurality of radiation detectors 10 can be inserted along the surface shape of the inspection object 1.

Next, in step 3, the controller 40 outputs a measurement command to each radiation detector 10 after the positioning control in the z direction for each radiation detector 10 is completed, and the surface contamination state by the radioactive substance. The measurement process of is executed, and the detection result is received as the response.

FIG. 10 is a conceptual diagram showing each driving state of the plurality of radiation detectors 10 according to the first embodiment of the present disclosure. 10 (a) to 10 (e) show a state in which each of the plurality of radiation detectors 10 is inserted along the surface shape of the object 1 to be inspected in the z direction after the positioning control is completed. It is shown as a conceptual diagram of a state in which the object 1 is looked down. Further, FIG. 10 (f) shows a cross-sectional view in the cross section shown in FIG. 10 (e).

Further, in FIGS. 10 (a) to 10 (e), the squares of the squares indicate the respective radiation detectors 10. Further, among the squares of the square, the square surrounded by the thick line frame indicates the radiation detector 10 that performs detection only by the sensitive surface 11 arranged on the side surface, and is inside the square surrounded by the thick line frame. The gray part indicates the inspection object 1.

Further, the numbers in the square indicate the maximum height of the inspection object 1 in the area of the bottom surface of each radiation detector 10. As can be seen from the comparison between FIGS. 10 (e) and 10 (f), the smaller the numerical value of the maximum height, the more the radiation detector 10 is inserted downward in the z direction and positioned. ..

The technical features of the radioactive contamination measuring device according to the first embodiment described above can be summarized as follows.
Feature 1: Radiation detector assembly in which radiation detectors 10 having a plurality of sensitive surfaces 11 (for example, 5 of the 6 rectangular parallelepiped surfaces excluding the signal extraction portion) are arranged in a matrix. The point to prepare 100. That is, a point of using a radiation detector assembly 100 using two or more radiation detectors 10 having a plurality of sensitive surfaces 11.
-Characteristic 2: In the radiation detector assembly 100, the individual radiation detectors 10 are configured to be independently movable in the z direction. That is, it has a drive system that can move independently in the same moving axis direction common to all the radiation detectors 10.
-Characteristic 3: The point of measuring the surface shape of the inspection object 1.

-Characteristic 4: Based on the measurement result, the insertion position (stop target position) of each radiation detector 10 is calculated so as to fit the surface shape of the inspection object 1.
-Feature 5: A point of performing positioning control for moving each radiation detector 10 to a calculated stop target position.
-Feature 6: A point in which radiation measurement by a plurality of radiation detectors 10 is collectively performed using a radiation detector assembly 100.

By providing the above-mentioned features 1 to 6, the radioactive contamination measuring device according to the first embodiment can realize the following remarkable effects.
-Effect 1: Acceleration of measurement Radiation from the inspection object 1 having a complicated shape can be measured quickly.
In particular, a plurality of radiation detectors 10 can be arranged side by side along the surface shape of the inspection object 1 and measured collectively. Further, by bringing the radiation detector 10 having the plurality of sensitive surfaces 11 close to the inspection object 1 from one direction, the sensitive surfaces 11 of the radiation detector 10 are brought close to all the surfaces other than the surfaces opposite to the approaching direction. be able to.

Therefore, it is not necessary to scan the radiation detector 10 along the surface of the inspection object 1, and it is possible to collectively measure almost all the surfaces of the inspection object 1 having a complicated surface shape. It becomes.
-Effect 2: Optimization of cost performance If the size of each radiation detector 10 constituting the radiation detector assembly 100 is reduced, the radiation detector 10 can be brought closer to the inspection object 1. As a result, the distance between the sensitive surface 11 and the surface of the inspection object 1 becomes shorter, so that the measurement time can be shortened.

Further, if there is a margin in the measurement time, it is possible to make the radiation detector assembly 100 smaller and perform measurement a plurality of times while moving the measurement site. In this way, by optimizing the size of the individual radiation detector 10 and the size of the radiation detector assembly 100 according to the needs, the cost performance can be easily optimized.

Finally, a derivative technique based on the radioactive contamination measuring apparatus described in the first embodiment will be described.
Derived Technique 1: Cross-sectional shape of each radiation detector 10 In the first embodiment described above, the case where the radiation detector 10 is a polygon and the cross-sectional shape is a quadrangle has been described as an example, but the radiation detection according to the present disclosure has been described. The cross-sectional shape of the vessel 10 may be other than a quadrangle, and may be a polygon, a circle, or the like. The difficulty of manufacturing, the degree of accessibility to the inspection object 1, and the like differ depending on the cross-sectional shape, but in either case, the same effect can be obtained.

Derivative technique 2: Number of sensible surfaces 11 The number of sensible surfaces (which surface of the detector is to be the sensible surface) is determined by the shape of the inspection object 1.
(1) When a complicated shape (inspection object with unevenness or inspection object that requires measurement inside the donut shape) is to be inspected, it is necessary to use five faces of a rectangular parallelepiped. ..
(2) On the other hand, when it is not necessary to measure the ceiling surface of the inspection object 1 and the bottom surface of the recess, it is not necessary to make the bottom surface of the rectangular parallelepiped the sensitive surface 11.
(3) When the inspection object 1 has no unevenness on the surface such as a cylinder or a rectangular parallelepiped, the sensitive surface 11 can be narrowed down to one or two surfaces.

Derivative technology 3: Size of each radiation detector 10 The distance between the radiation detector 10 and the inspection object 1 (plane) is determined from the required specifications of the measurement time, but individual radiation detection is performed according to the required distance. The size of the vessel 10 is decided.

Derivative technique 4: Grouping of individual radiation detectors 10 As the size of each radiation detector 10 is reduced, it becomes easier to approach the inspection object 1. However, since the radiation dose incident on the radiation detector 10 is reduced, the error due to the fluctuation of the counting rate becomes large.

As a countermeasure, the identification of the contaminated place (positional resolution) becomes worse when there is contamination, but as explained in FIG. 5 above, a plurality of radiation detectors 10 are grouped and their outputs are added. If measures are taken to increase the counting rate, the fluctuation error can be reduced. Therefore, the number of radiation detectors to be grouped can be determined by the optimum value of the position resolution and the amount of error.

Derived technique 5: Size of radiation detector assembly 100 When the inspection object 1 is measured at one time, the size should be such that the radiation detector assembly 100 can cover the entire surface of the inspection object 1. Is required. On the other hand, if the measurement time is sufficient or if the cost of the device is to be reduced, the radiation detector assembly 100 is made smaller as described in FIGS. 4 (b) and 4 (c) above. By measuring multiple times, it is possible to measure a large inspection object 1. The radiation detector assembly 100 is defined as a combination of two or more radiation detectors 10.

Derived technique 6: Direction to move (insert) the radiation detector 10 It is most natural to insert the radiation detector 10 from top to bottom because the load on the drive system is reduced, but the insertion direction is Not limited to the vertical direction. However, when the radiation detector 10 is inserted from below, sideways, or diagonally, the surface opposite to the insertion direction and the bottom surface cannot be measured, but the other surfaces can be measured.

Derivative Technique 7: Shape Recognition of Inspection Object 1 The outline of three specific examples of the three-dimensional shape recognition method has been described in the first embodiment, but in the radioactive contamination measuring apparatus according to the present disclosure, the outline is described. Various techniques capable of measuring the surface shape can be applied. For example, the application of various techniques such as 3D scanner, image processing, and contact detection can be considered.

Derivative technique 8: Inspection of the surface opposite to the insertion direction With the method described in the first embodiment, the surface opposite to the insertion direction of the radiation detector 10 cannot be measured. However, when the radiation detector 10 is inserted from above, the surface of the transport mechanism 50 on which the inspection object 1 is mounted is made of a substance (net, film, etc.) having a low radiation shielding effect, and the transport mechanism 50 is configured. By placing the radiation detector 10 at the bottom, it is conceivable to measure the bottom surface of the inspection object 1.

Further, it is also conceivable to measure once, then turn the inspection object 1 upside down and measure again with the bottom surface facing the top surface.

1 Inspection object, 10 Radiation detector, 11 Sensitive surface, 12 Bumper sensor, 13 Distance sensor, 14 Signal processing unit, 15 Drive guide, 20 Drive unit, 30 Shape measurement unit, 40 Controller, 50 Conveyance mechanism, 100 Radiation Detector assembly (matrix-like radiation detector), 101 adder amplifier.

Claims (4)

An aggregate of radiation detectors using two or more radiation detectors that detect the amount of surface contamination caused by radioactive substances in the inspection target, and
A shape measuring unit that measures the surface shape of the object to be inspected,
A controller for executing a determination process of whether or not the surface contamination amount is within the permissible value from each detection result of the radiation detector is provided.
Each of the radiation detectors has a plurality of sensitive surfaces, and also has a drive system that can move independently with respect to the same moving axis direction common to all the radiation detectors, and the controller. Performs positioning control via the drive system for each of the radiation detectors so that the distance from the surface shape is within the allowable distance range based on the measurement result by the shape measuring unit. A radioactive contamination measuring device that executes the determination process based on the detection results acquired from each of the radiation detectors after the positioning control is completed. A transport mechanism for moving the inspection object is further provided in the shape measurement area for measuring the surface shape of the inspection object by the shape measurement unit and the inspection area for executing the positioning control.
The controller
By moving the inspection object to the shape measurement area via the transport mechanism and outputting a measurement command to the shape measurement unit, the shape measurement unit responds to the surface shape of the surface shape in response to the measurement command. Get the measurement result,
After acquiring the measurement result of the surface shape, the inspection object is moved to the inspection area via the transport mechanism.
Based on the measurement result of the surface shape, the positioning control is executed by outputting a movement command to each of the radiation detectors.
By outputting a measurement command to each of the radiation detectors after the positioning control is completed, the determination process is performed based on the detection results obtained from each of the radiation detectors as a response to the measurement command. The radioactive contamination measuring device according to claim 1. In a three-dimensional space defined by the X-axis, Y-axis, and Z-axis that are orthogonal to each other, when the same movement axis direction is the Z-axis direction,
The radioactive contamination according to claim 1 or 2, wherein the radiation detector assembly is configured by arranging the radiation detectors in a matrix in an XY plane defined by the X-axis and the Y-axis. measuring device. With respect to the radiation detectors arranged in the matrix, two or more adjacent radiation detectors are grouped, and an adder amplifier for adding the counts of the radiation detectors is further provided for each group.
The radioactive contamination measuring device according to claim 3, wherein the controller executes the determination process using the addition result obtained for each of the groups as the detection result.

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