JPH0688874A - Contamination inspecting device - Google Patents

Abstract

PURPOSE:To shorten the inspecting time and decontaminating time of the title device so as to prevent the spreading of contamination, such as cross- contamination, etc. CONSTITUTION:The device inspects an object 20 to be inspected for surface contamination by moving a radiation detector 10 on the surface of the object 20 and monitoring the output of the detector 10. The device is provided with a decontaminating wiping mechanism 13 which moves on the surface of the object 20 following the detector 10 at least when the detector 10 moves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pollution inspection device for inspecting and decontaminating a transportation container used for transporting radioactive waste such as returned waste in a facility for handling reprocessed waste. .

[0002]

2. Description of the Related Art Radioactive waste transported from overseas to reprocessing facilities is stored in a dedicated waste transport container. FIG. 5A shows an example of the waste transport container. The waste transport container 1 is configured to accommodate a plurality of closed containers 2a to 2d in which wastes are enclosed.

In order to reuse the waste transport container 1, it is necessary to confirm that the waste transport container 1 is not radioactively contaminated, and if it is contaminated, decontaminate the contaminated site. There is.

Therefore, conventionally, the waste transportation container 1 after use is used.
In contrast, the inside surface of the waste transport container is scanned with a radiation detector to inspect for radioactive contamination. Decontamination work was performed such as moving to a location and wiping the entire inner surface of the waste transport container in a separate process.

[0005]

However, in the above-mentioned conventional contamination inspection apparatus, the contamination inspection and the decontamination work are separate steps, and the waste transportation container in which the radioactivity concentration above the specified level is detected is concerned. Had to carry out decontamination work again, there is a drawback that a long working time is required when contamination is detected.

The present invention has been made in view of the above circumstances, and the contamination inspection and the decontamination work can be performed in the same step to shorten the inspection time, and the decontamination work can be selectively performed. Therefore, it is an object of the present invention to provide a contamination inspection device capable of shortening the decontamination time and preventing the spread of contamination such as cross contamination on a non-contaminated portion.

[0007]

In order to achieve the above object, the contamination inspection apparatus of the present invention moves a radiation detector along the surface of an object to be inspected, and monitors the radiation detector output at that time. The apparatus for inspecting the surface of the object for contamination is provided with a decontamination wiping mechanism that follows the surface of the object after the radiation detector moves at least when the radiation detector moves. I decided.

[0008]

In the contamination inspection apparatus of the present invention, when the radiation detector moves along the surface of the object to be inspected, the decontamination wiping mechanism moves following the object surface after the radiation detector moves. To do. Therefore, for example, when contamination is detected from the output of the radiation detector, by driving the decontamination wiping mechanism that follows the radiation detector and passes through the contaminated location, only the contaminated location is driven. Can be selectively decontaminated.

[0009]

EXAMPLES Examples of the present invention will be described below.

FIG. 1 shows a functional block of a pollution inspection device according to an embodiment of the present invention. The contamination inspection apparatus of this embodiment includes a radiation detector 10 made of a scintillation detector such as plastic or ZnS, and the radiation detector 10 is driven by a detector driving unit 11 so that the waste transportation container (not shown in FIG. 1). It is possible to move on the surface (shown).

The radiation detector 10 is equipped with a wiping mechanism 12 capable of performing a wiping operation with a filter paper. The wiping mechanism 12 is attached to the radiation detector 10 at a position following the radiation detector 10.
Therefore, the wiping mechanism 12 can move to the same position on the surface of the waste transport container on which the radiation detector 10 has moved, following it thereafter.

The wiping mechanism 12 is driven and wiped by a wiping drive unit 13. The wiping drive unit 13 retracts the wiping mechanism 12 to a position where it does not come into contact with the inner surface of the container during radiation concentration measurement, and when a decontamination command is received from a sequencer described later, the wiping mechanism 12 is removed.
It has the function of bringing the filter paper surface into contact with the inner surface of the container for decontamination.

The radiation detection signal detected by the radiation detector 10 is input to the measuring section body 14. The measuring section main body 14 forms a control center of the apparatus main body together with the sequencer 15. The measuring unit main body 14 and the sequencer 15 are shown in FIG.
The operation based on the operation flow of 1.

The measuring unit main body 14 manages the operation of the entire apparatus and gives a measurement start command to the sequencer 15 when receiving a measurement start signal from the outside. Further, the radioactivity concentration is measured based on the radiation detection signal from the radiation detector 10, and when the measured radioactivity concentration exceeds a specified value, a decontamination instruction is output to the sequencer 15.

The sequencer 15 also includes a detector driving section 11
Also, a sequence program relating to the operation of the wiping drive unit 13 is stored, and each program is activated by a measurement start command and a decontamination command input from the measurement unit main body 14.

In the contamination inspection apparatus of this embodiment, the radiation detector 10, the detector driving unit 11, the wiping mechanism 12, and the wiping driving unit 13 constitute one unit, and the unit is inside the waste transport container 20. To move. FIG. 2 shows the mechanical positional relationship of the unit parts.

The detector driving unit 11 rotates the rotary body 22 about the rotary shaft 21, moves the rotary body 22 in the axial direction, and controls the rotary shaft 21 to be in a vertical state and a horizontal state. It has a function. Rotor 2 of detector drive unit 11
2, the radiation detector 10 is fixed in a state perpendicular to the rotation shaft 21.

A wiping drive unit 13 is held on the side surface of the radiation detector 10 via a support arm 23 whose longitudinal direction is oriented in the axial direction of the detector drive unit 11. And
The wiping mechanism 12 to which the filter paper is attached is held by the wiping drive unit 13 so as to be able to expand and contract in the direction orthogonal to the rotation axis 21.

The radiation detector 10 and the wiping mechanism 12 are
The support arms 23 are spaced apart by the length of the support arm 23, but when scanning the surface of the waste transport container 20,
Make sure that the radiation detector 10 passes through the inspection point before the wiping mechanism 12. For example, in the case shown in FIG. 2, it is moved upward. This causes the wiping mechanism 12 to move behind the radiation detector 10 so as to follow the radiation detector 10 with a delay from the radiation detector 10 by a time corresponding to the length of the support arm 23. Next, the operation of the present embodiment configured as described above will be described with reference to the flowchart of FIG.

When a measurement start signal is input from the outside, the detector drive unit 11 is controlled to move the radiation detector 10 to the measurement start point on the inner surface of the waste transport container 20 and measure the radioactivity concentration at that position. . Then, the measured radioactivity concentration (count value) is compared with a preset standard value.
When the inner surface of the container is contaminated, the contamination density at the contaminated portion becomes extremely high as shown in FIG.

As a result of the comparison, if the count value is smaller than the specified value, it is not contaminated and the radiation detector 10 is moved to the next measurement point. Further, as a result of the comparison, when the count value is larger than the specified value and it is determined that there is contamination, a decontamination command is output from the measurement unit main body 14 to the sequencer 15.

Here, the moving direction of the measuring point by the radiation detection 10 is stored in the sequence program, and as described above, the radiation detector 10 always precedes the wiping mechanism 12, and the wiping mechanism 12 detects the radiation. The wiping mechanism 12 passes the measurement position after the device 10 is followed and a predetermined time has elapsed.

Therefore, the sequence program driven by the decontamination command waits until the wiping mechanism 12 reaches the detected contaminated portion and drives the wiping drive unit 13. When the wiping mechanism 12 faces the contaminated portion, the wiping drive unit 13 brings the retracted wiping mechanism 12 into contact with the contaminated portion on the inner surface of the container to perform the wiping operation with the filter paper.

When the radiation detector 10 has scanned the entire measurement range, the decontamination work is also completed.
In the case of the waste transport container 20, since there is almost no surface contamination, the possibility that the final measurement point is contaminated is extremely low, so the decontamination work will be completed when the scanning is completed.

As described above, according to this embodiment, the wiping mechanism 12 that follows the measurement position after the radiation detector 10 is interlocked with the movement of the radiation detector 10 along the container surface.
Since the above is provided, the contamination inspection and the decontamination work can be performed in the same process, and the inspection time can be significantly shortened. In addition, since the decontamination work is performed by selecting only the areas with high contamination density, it is possible to shorten the decontamination time, and wipe the areas with high contamination density by wiping the areas with low contamination density. You can avoid cross contamination. The present invention can also be applied to the inspection of the outer surface of the waste transport container 20.
It can be applied to other than the above.

Further, in the above embodiment, the radiation detector 10 and the wiping drive unit 13 are separated by the support arm 23, but they can be replaced with another structure, for example, a telescopic arm. The present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention.

[0027]

As described in detail above, according to the present invention, the contamination inspection and the decontamination work can be carried out in the same process to shorten the inspection time, and the decontamination work can be selectively performed to remove the decontamination work. Shortening of dyeing time and cross contamination such as non-contamination
A pollution inspection device capable of preventing the spread of pollution can be provided.

[Brief description of drawings]

FIG. 1 is a functional block diagram of a pollution inspection device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a unit portion put in a container of the contamination inspection device shown in FIG.

FIG. 3 is an operation explanatory view of the contamination inspection device shown in FIG.

FIG. 4 is a diagram showing a relationship between a contamination location and a contamination density in the contamination inspection device shown in FIG.

FIG. 5 is a perspective view of a waste transport container.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Radiation detector, 11 ... Detector drive part, 12 ... Wiping mechanism, 13 ... Wiping drive part, 14 ... Measuring part main body, 15
… Sequencer, 20… Waste transport container.

Claims (1)

[Claims] 1. A contamination inspection apparatus that moves a radiation detector along a surface of an object to be inspected and monitors an output of the radiation detector at that time to inspect for contamination of the surface of the object. A contamination inspection apparatus comprising a decontamination wiping mechanism that moves along the surface of an object after the radiation detector has moved when the instrument is moved.