JPH0641978B2 - Radioactive contamination inspection device - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention is a radioactive contamination inspection for measuring the radioactive contamination level of various solids generated in a facility that handles radioactive substances and is generated in the radiation controlled area. Regarding the device.

[Technical background of the invention and its problems] Generally, in a facility that handles radioactive substances, various solid materials such as paper, metal, and waste used in the control area are stored in a certain container. When the solid matter contained in this container is carried out of the radiation controlled area, the radioactive contamination level is measured, and only those whose radioactive contamination level is within a certain standard are carried out of the radiation controlled area. If the radioactive contamination level is higher than a certain level, it will be stored in the facility.

Conventionally, such measurement of the radioactive contamination level is mainly performed manually, and there is a problem that this measurement requires a lot of time and labor.

Further, conventionally, the measurement of this radioactive contamination level mainly measures the surface contamination by beta ray measurement, so in the case of a container containing a mixture of various radioactive contaminants, the container It is not possible to judge which part contains the radioactively contaminated substance, etc.
Also, if a radioactively contaminated substance is contained near the center of the container thickness, this beta ray measurement shows the presence of the radioactive contaminant because the solid object itself blocks the radiation. I can't. Therefore, radioactive pollutants may be discharged to the external mirror and cause environmental pollution. Furthermore, even if non-radioactive pollutants are contained in the same container, they must be stored together with the radioactive pollutant in the facility in order to store the whole container. However, there is a problem in that the storage amount may increase.

[Object of the Invention] The present invention has been made in response to such a conventional situation, and can reduce labor and efficiency of work in measuring a radioactive contamination level, and at the same time, carry out radioactive pollutants to an external environment. An object of the present invention is to provide a radioactive contamination inspecting device that does not cause environmental pollution, stores non-radioactive pollutants in the facility, and does not increase the storage amount in the facility.

[Summary of the Invention] That is, the present invention relates to a radioactive contamination inspecting apparatus for measuring the radioactive contamination level of a solid material housed in a container. A shield container having a plurality of radiation detectors, the plurality of radiation detectors arranged in the container transfer passage inside the shield container so as to face each other with a movable gap, and the container is movable along the container transfer passage. A radioactive contamination inspecting device, comprising: a container moving device for guiding.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, details of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the radioactive contamination inspection device of the present invention. In the figure, reference numeral 1 indicates a lead shield container. A container transfer passage 2 is formed in the center of the inside of the shielding container 1, and the container transfer passage 2 includes a container transfer rail 3, a container transfer stand 4, and a container transfer pulse motor 5. A moving device 6 and a weight measuring device 7 are arranged. An inlet door 8a and an outlet door 8b are arranged at both ends of the container transfer passage 2, and door opening / closing motors 9a and 9b are provided above the respective doors 8a and 8b.
Are arranged. Further, in the vicinity of the central portion of the container transfer passage 2, the radiation detectors 10a and 10b composed of six NaI detectors arranged in a line in a direction perpendicular to the container transfer direction of the container transfer passage 2 in a horizontal direction. Of the radiation detectors 10a and 10b, the radiation detector 10a arranged above is connected to the radiation detector moving motor 11. A television camera 12 is arranged above the entrance door 8a outside the shielding container 1.

In the radioactive contamination inspection device configured as described above, the second
The radioactive contamination level is measured according to the configuration shown in the block diagram shown in the figure. That is, the solid material to be measured for the radioactive contamination level is stored in the predetermined container 13
First, the inlet door opening / closing motor 9a is driven to open the inlet door 8a, and the predetermined container 13 is placed on the container transfer table 4 in the shielded container 1. Next, the entrance door opening / closing motor 9a is driven again to close the entrance door 8a. At this time, the radioactive contamination inspecting apparatus recognizes the measurement target of the radioactive contamination level by the television camera 12. After that, the radioactive contamination inspection device is controlled by an external control (not shown), and the measurement is performed automatically.

The weight of the container 13 accommodated in the shielded container 1 is first measured by the weight measuring device 7, and then the container transfer pulse motor 5 is driven to move the container transfer rail 3 and the container transfer table 4 together with the radiation detector 10a. It is transferred to the middle of 10b. The ends of the container 13 are the radiation detectors 10a and 10b.
When the pulse motor 5 for transferring the container is stopped, the gamma dose is measured by the radiation detectors 10a and 10b for a preset time.
When this measurement is completed, the container transfer pulse motor 5 is again used.
Is driven, the container 13 is further moved by 10 cm, and gamma ray measurement is performed again by the radiation detectors 10a and 10b. In this way, the gamma ray measurement is repeated 10 times every 10 cm. The height of the radiation detector 10a is adjusted by the detector moving motor 11 according to the size of the container measured at this time. The data of the radioactive contamination level measurement of the container 13 measured in this way is guided to an external data processing device (not shown) and processed, and then outside the radiation controlled area depending on the level of the radioactive contamination level of the container 13. What can be shipped to
The door is moved toward the exit door 8b, the door opening / closing motor 9b is driven, and the exit door 8b is opened. After this, the workers are carried out to outside the radiation controlled area. If the radioactive contamination level is higher than a certain standard, it is returned toward the entrance door 8a, the door opening / closing motor 9a is driven, and the entrance 8a is opened and returned to the radiation controlled area.

On the other hand, the measured data is output as shown in FIG. 3, for example. In the figure, the squares that are divided vertically and horizontally indicate the parts of the container 13 that are 10 cm square, and the numbers shown in the squares indicate the measured radiation dose in units of microcurie and the dots shown in the squares. The pattern by
The density indicates the amount of radiation measured. The numbers and letters shown in the lower part of the figure represent the measurement conditions, the radioactivity concentration of the measurement analysis result, the maximum surface dose rate, and the like.

As a result of measuring the radioactive contamination level in this way, the container 13 returned to the radiation controlled area because the radioactive contamination level was above a certain standard, the container 13 in which the radioactive contamination level was measured It can be seen whether a part contains a substance with a high level of radioactive contamination. Therefore, in some cases, only the substance having a high level of radioactive contamination is stored in the container 13
By taking out from the inside, the substance contained in the other container 13 may be able to be carried out to the outside of the radiation controlled area.

That is, in the radioactive contamination inspection device configured as described above, since the radioactive contamination level of various solids carried out from the radiation controlled area can be measured fully automatically, the labor saving and efficiency of this work are greatly reduced. In addition to the above, the measurement of the radioactive contamination level of the solid material contained in the container shows the part of the container and the degree of the radioactive contamination level of the substance contained in the container. Therefore, the container 13
Only solid substances with high radioactivity level can be removed from inside, and other solid substances with low radioactivity level can be carried out to outside of the radiation controlled area. Therefore, solid substances having a low level of radioactive contamination are not unnecessarily stored in the radiation controlled area, and the amount of stored substances can be reduced. Also,
In the present embodiment, since the radioactive contamination level is measured by gamma ray measurement, it is possible to detect a solid substance having a high radioactive contamination level existing in the vicinity of the central portion of the container 13, and the radioactive contamination level is high. It is also possible to prevent solid objects from being carried out of the radiation controlled area.

Although the radioactive contamination level is measured by gamma ray measurement in the present embodiment, the present invention is not limited to this embodiment, and the radiation detectors 10a, 10b are not limited thereto.
It is of course possible to measure the surface contamination by beta ray measurement by exchanging the.

[Advantages of the Invention] As described above, the radioactive contamination inspecting apparatus of the present invention can measure the radioactive contamination level of the solids carried out from the radiation controlled area in a fully automatic manner. In addition to being able to improve efficiency, substances with high radioactive contamination levels will be carried out of the radiation control area, will not cause external environmental pollution, and low radioactive contamination level substances mixed with high radioactive contamination level substances are unnecessary. Moreover, it is stored in the radiation controlled area, and the storage amount does not increase.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the radioactive contamination inspection device of the present invention, and FIG. 2 is a block diagram showing the configuration of FIG.
FIG. 3 is an explanatory view showing an example of the ejection pattern of the measurement result. 1 ... Shielded container 2 ... Container transfer passage 6 ... Container moving device 10a, 10b ... Radiation detector 13 ... Container

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukio Yuki 4-1 Ukishimacho, Kawasaki-ku, Kawasaki-shi, Kanagawa Nihon Nuclear Power Company Limited (72) Inventor Yukio Yoshimura 4 Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa No. 1 Inside the Research Institute of Japan Nuclear Power Company (72) Inventor Mikio Wada 1-1-1 Shibaura, Minato-ku, Tokyo Inside Toshiba Head Office

Claims (1)

[Claims] 1. A radioactive contamination inspecting apparatus for measuring a radioactive contamination level of a solid contained in a container, the shielding container having a container transfer passage that shields radiation from the outside and moves the container inside. A plurality of radiation detectors that are arranged opposite to each other in the container transfer passage inside the shield container with a movable distance therebetween, and a container moving device that guides the container movably along the container transfer passage. And a radioactive contamination inspecting device.