JP2006106010A - Body surface contamination monitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a body surface contamination monitor capable of detecting radioactive contamination of the whole body surface of a subject with a constitution where the number of radiation detectors required for the body surface contamination monitor is reduced and the apparatus constitution is simplified. <P>SOLUTION: The body surface contamination monitor comprises a case formed of a plurality of disassemblable plate materials; a detecting section formed by bundling plastic scintillation fibers for detecting the existence of radioactivity in a plate shape and fixing it to the case; and a measuring means for measuring the activity detected from the detecting section. The body surface contamination monitor detects the radioactive contamination of the whole body surface of the subject. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a radiation detection apparatus for confirming that a body surface is not radioactively contaminated when an operator who enters a management area at a nuclear facility such as a nuclear power plant leaves the management area, and It relates to body surface contamination monitors using this, especially radiation detection devices that can be quickly installed at sites where radioactive contamination may have occurred, such as criticality accidents, and determine the presence or absence of radioactive contamination of the human body. And a body surface contamination monitor using the same.

FIG. 6 shows a configuration example of a conventional body surface gate monitor. The body surface gate monitor 7 shown in FIG. 1 includes a front detector housing portion 8, a rear detector housing portion 9, a side detector housing portion 10, and a head detector housing portion 11. Radiation detectors 81 to 86 are accommodated in the front detector housing portion 8 facing the front surface of the subject 2b entering the gate monitor, and the rear detector housing portion 9 facing the rear surface of the subject 2b The radiation detectors 91 to 96 are accommodated. Further, the left and right side detector housing portions 10 facing the left and right side surfaces of the subject 2b accommodate the radiation detectors 101 to 108.
Note that the left and right side detector housing portions 10 are attached to the revolving door as shown in FIG. 6C with respect to the left and right entrances of the body surface gate monitor 7. Further, the radiation detectors 111 to 113 are accommodated in the head detector accommodating portion 11 that moves up and down according to the height of the subject 2b.

  In such a body surface gate monitor 7, when an operator entering the gate monitor stops at a measurement position and becomes ready for measurement, the radiation density of the whole body surface of the operator is measured by each radiation detector. When the surface contamination density exceeds a predetermined threshold, a warning is issued to the radiation manager (see, for example, Patent Document 1).

JP-A-8-248134 (pages 3-4, FIG. 9)

  However, the above-described conventional body surface contamination monitor requires a large number of radiation detectors in order to measure the radioactive contamination distribution on the entire body surface of the subject.

  As described above, since the conventional body surface contamination monitor requires a plurality of radiation detectors, the configuration of the entire measuring apparatus becomes large, and it is difficult to move and install in response to radioactive contamination such as a criticality accident. there were.

  The present invention has been made in view of the above problems, and provides a radiation detection device capable of detecting radioactive contamination of the entire body surface of a subject with a simple configuration, and a body surface contamination monitor. By reducing the amount of radiation detectors required for the system, it is possible to simplify the equipment configuration, and to obtain a body surface contamination monitor that can be moved and installed in response to radioactive contamination in critical accidents, etc. Objective.

  The body surface contamination monitor according to the present invention includes a housing composed of a plurality of disassembleable plates, a detection unit fixed to the housing by bundling plastic scintillation fibers for detecting the presence or absence of radioactivity in a plate shape, Measuring means for measuring the radioactivity detected from the detection unit.

  The body surface contamination monitor according to the present invention includes a housing composed of a plurality of disassembleable plates, a detection unit fixed to the housing by bundling plastic scintillation fibers for detecting the presence or absence of radioactivity in a plate shape, Since the measuring means for measuring the radioactivity detected from the detection unit is provided, it is possible to obtain a body surface contamination monitor capable of detecting radioactive contamination of the entire body surface of the subject with a simple configuration. .

Embodiment 1 FIG.
FIG. 1 is a layout view showing an example of a body surface contamination monitor to which the first embodiment of the present invention is applied.
In the figure, reference numeral 1 denotes a detection unit in which plastic scintillation fibers 1a are bundled in a plate shape, and this detection unit 1 is arranged around the subject to detect the presence or absence of radioactivity on the body surface of the subject. This constitutes a radiation detection apparatus.
The plastic scintillation fiber 1a has low rigidity and can be bent to some extent.
2a is a subject to be examined for radioactive contamination.
Reference numeral 3 denotes a housing for fixing the detection unit 1, in which a subject 2 a enters and the presence or absence of radioactive contamination on the body surface is measured.
4a is a measuring device such as an amplifier.

For example, the plastic scintillation fiber 1a can be placed around the subject 2a by attaching the plastic scintillation fiber 1a to the wall surface of the case 3 and the subject 2a entering the case 3.
Thereby, even if a radioactive substance is attached to any part of the body surface of the subject 2a, the radiation emitted from the subject 2a passes through the plastic scintillation fiber 1a, thereby directly detecting the presence or absence of radioactivity. can do.

For example, when a radioactive substance is attached to the back of the subject 2a, the plastic scintillation fiber 1a is also arranged on the back surface of the subject 2a, so that it is directly shielded by the subject 2a itself. Can detect radiation.
If the detection unit 1 does not surround the subject 2a, specifically, if the plastic scintillation fiber 1a is not disposed on the back surface of the subject 2a, it adheres to the body surface of the subject 2a. Since the radiation from the radioactive substance cannot enter the detection unit unless it passes through the subject 2a itself, the intensity of the radiation is attenuated, and the accuracy of detecting radioactive contamination on the body surface of the subject 2a is high. descend.

FIG. 2 is a diagram for explaining a more specific configuration of the detection unit 1 in FIG.
The plastic scintillation fiber 1a is obtained by processing a plastic scintillator, which is a substance that emits fluorescence when radiation is incident, into an optical fiber.
When radiation enters the plastic scintillation fiber 1a, it emits fluorescence. Since this plastic scintillation fiber 1a is an optical fiber, this light is detected by a photodetector 5 attached to one end of the plastic scintillation fiber.
The output signal from the photodetector 5 is measured by the measuring device 4a.
The radiation detection mechanism described above is the same at any position on the plastic scintillation fiber 1a. That is, it is possible to detect whether radiation is incident on any position on the plastic scintillation fiber 1a.

  Since the plastic scintillation fiber 1a can be bent, the plastic scintillation fiber 1a can be bent in an annular shape or arranged along the housing as shown in FIG. Thereby, the radiation emitted in the 2π direction from the inside of the plastic scintillation fibre 1a can be detected by one plastic scintillation fibre 1a.

  Since the plastic scintillation fiber 1a is soft and can be bent, the plastic scintillation fiber 1a is continuously provided at a movable portion in the above-described body surface contamination monitor, for example, the base portion of the door where the subject 2a enters and exits. There is no problem even if it is arranged.

  By bundling a plurality of plastic scintillation fibres 1a in a plate shape, it is possible to increase the area of the detection section and improve the sensitivity. Further, by bundling the plastic scintillation fibers 1a in a plate shape, it is possible to detect radiation emitted not only in the circumferential direction but also in the longitudinal direction.

  Even if a plurality of plastic scintillation fibres 1a are used, they are bundled into a plastic scintillation fiber 1a plate and connected to one optical detector 5, so that they can enter all plastic scintillation fibers 1a with only one measuring device 4a. Can be detected.

Embodiment 2. FIG.
FIG. 3 is a layout view showing an example of a body surface contamination monitor to which the second embodiment of the present invention is applied.
In the figure, reference numeral 1 denotes a detection unit in which plastic scintillation fibers 1a are bundled in a plate shape.
2a is a subject to be examined for radioactive contamination.
Reference numeral 3 denotes a housing for fixing the detection unit 1, in which a subject 2 a enters and measures the presence or absence of radioactive contamination on the body surface.
4a is a measuring device such as an amplifier.

  As shown in FIG. 3, a plurality of radiation detectors, which are bundled in a plate shape with plastic scintillation fibers 1a and arranged in a ring shape along the casing 3, are arranged in the vertical direction to detect light for each bundle of scintillation fibers 1a. The measuring instrument 4a is attached.

  By measuring the incident radiation for each bundle of scintillation fibers 1a, it is possible to measure the contamination distribution on the body surface in the height direction of the subject 2a.

  By visualizing the radiation intensity detected for each bundle of scintillation fibers 1a and visually showing which part of the subject 2a is contaminated with body surface radiation as shown in FIG. A good body surface contamination monitor can be obtained.

Embodiment 3 FIG.
FIG. 5 is a layout diagram showing an example of a body surface contamination monitor and parts to which the third embodiment of the present invention is applied.
In the figure, reference numeral 1 denotes a detection unit in which plastic scintillation fibers 1a are bundled in a plate shape.
2a is a subject to be examined for radioactive contamination.
3a is a housing for fixing the detection unit 1, and the subject 2a enters the case, and measures the presence or absence of radioactive contamination on the body surface.
4a is a measuring device such as an amplifier. Moreover, 1c winds up the plastic scintillation fiber 1c at the time of disassembly in order to transfer the body surface contamination monitor.
3b is a part obtained by disassembling a portion constituting the housing 3a of the body surface contamination monitor.

By arranging the plastic scintillation fiber 1a constituting the detection unit 1 in an annular shape, it is possible to detect radiation radiated from the inside where the plastic scintillation fiber 1a is disposed by one detection unit.
Even when a plurality of plastic scintillation fibers 1a are bundled in a plate shape and are used, a single measuring device 4a is sufficient to insert them into one photodetector.
As a result, as the body surface contamination monitor, the number of radiation detectors necessary for detecting the radioactive contamination on the body surface of the subject 2a without leaking can be reduced, and the device configuration can be simplified.

  In order to obtain the distribution of radioactive contamination on the body surface in the height direction of the subject 2a, even when a plurality of bundles of plastic scintillation fibers 1a are arranged in layers, it is only necessary to measure the number of divisions in the height direction Compared with the number of radiation detectors required to obtain the same performance in the conventional body surface contamination monitor, the equipment configuration can be greatly simplified.

  By simplifying the equipment configuration of the body surface contamination monitor, it is possible to reduce the strength of the housing that holds the radiation detector.

  From the above, the number and weight of each part constituting the body surface contamination monitor can be greatly reduced, and it can be easily carried in and installed at a site where radiological contamination such as a criticality accident is a concern. it can.

  By using the plastic scintillation fiber 1a for the detection unit, a portable body surface contamination monitor can be obtained.

As described above, according to the present invention, the presence or absence of radioactivity on the body surface of the subject is detected by arranging the detection unit in which plastic scintillation fibers are bundled in a plate shape around the subject. Because I configured
Even if radioactive contaminants adhere to the body surface of the subject, not only can this be detected, but since plastic scintillation fibers are used, the subject should be bent in a ring and wrapped around It becomes easy to arrange and install, and it is possible to easily carry in and install on site such as criticality accidents.

In addition, a radiation detection device configured to detect the presence or absence of radioactivity on the body surface of the subject by arranging a detection unit in which plastic scintillation fibers are bundled in a plate shape around the subject, and
Since it has a measuring means for measuring the radioactivity detected from the radiation detection device,
The structure of the body surface contamination monitor can be simplified, and the strength of the housing required to reduce the need to hold each device is also reduced. For example, the housing itself for attaching a plastic scintillation fiber is also reduced. It can be simplified.
Therefore, for example, it is possible to install nita on body surface contamination in a simplified building such as a barrack, and there is an effect that it can be easily carried and installed on the site such as a criticality accident.

5 is a diagram showing an example of the arrangement of a body surface contamination monitor according to Embodiment 1. FIG. 4 is a diagram for explaining a specific configuration of a detection unit according to Embodiment 1. FIG. It is a figure which shows an example of arrangement | positioning of the body surface contamination monitor in Embodiment 2. FIG. It is a figure which shows an example of the result display of the body surface contamination monitor in Embodiment 2. FIG. It is a figure which shows an example of the body surface contamination monitor and components in Embodiment 3. It is the schematic of the radiation imaging device in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a Plastic scintillation fiber, 2a Subject, 3a housing | casing, 3b Part of housing | casing 4a Measuring device, 5 photodetectors, 6 Examples of output screens, 7 Body surface gate monitor.

Claims (2)

A housing composed of a plurality of members that can be dismantled;
A detection unit that is fixed to the casing by bundling plastic scintillation fibers for detecting the presence or absence of radioactivity in a plate shape;
A body surface contamination monitor, comprising: measuring means for measuring the radioactivity detected from the detection unit. The body surface contamination monitor according to claim 1, wherein a plurality of detection units are arranged in a vertical direction of the housing.

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