JPH0664151B2 - Pollution monitor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a pollution monitor device for measuring the concentration of radioactive contaminants on the surface of an object to be measured in a nuclear power plant, a facility handling radioactive substances, or the like.

(Prior Art) A conventional contamination monitoring device includes a gas flow detector that detects β-rays or γ-rays emitted from the surface of the measured object in order to measure the radioactive contamination concentration on the surface of the measured object. Alternatively, a large and flat radiation detector such as a plastic detector has been used. FIG. 2 shows a schematic configuration diagram of a conventional pollution monitor. In the figure, a pollution monitor 20 is composed of a large flat plate radiation detector 9, a shield 10 that shields the intrusion of external radiation, and an object to be measured 1 installed in the shield 10. The radiation detector 9 includes a scintillator 91, a photodetector (photomultiplier tube) 7, and a light guide 92. Further, 4 is a radioactive substance attached to the surface of the DUT 1, and 5 is radiation emitted from this radioactive substance.

(Problems to be Solved by the Invention) However, when the unevenness of the surface is severe like the DUT 1, the flat plate radiation detector 9 is brought as close as possible to the DUT 1 and the distance to the DUT 1 is increased. However, due to the unevenness of the DUT 1, it is difficult to approach the object over a certain distance. Because of this, the long range β
Unlike rays and γ rays, α rays and the like having a short range do not reach the radiation detector 9 and there is a problem that the detection thereof is difficult.

The present invention has been made in view of the above points, and an object thereof is to effectively solve the problems of the prior art, to provide a pollution monitoring device having a simple configuration and improving its measurement performance.

(Means for Solving the Problems) In order to achieve such an object, the present invention is a scintillator cloth-like member formed in a cloth shape and provided to cover or wrap the object to be measured, This scintillator cloth-like member and a dark room for accommodating the object to be measured, and the scintillator cloth-like material when radiation from radioactive contaminants of the object to be measured which is arranged on the inner wall of the dark room enters the scintillator cloth-like member. It is characterized by including a photodetector for detecting the light emitted by the member and an arithmetic circuit for arithmetically processing the output from the photodetector.

(Operation) By the technical means configured in this manner, the scintillator cloth-like member covers the measurement object or wraps the measurement object, and when the scintillator cloth-like member is in close contact with or close to the measurement object, the α-ray with a short range is obtained. Can be sufficiently detected, the configuration is simple, and the detection performance is improved.

(Example) Next, the Example of this invention is described in detail based on drawing.

FIG. 1 shows a schematic configuration diagram of an embodiment of the present invention. In the figure, parts having the same functions as those in FIG. 2 are designated by the same reference numerals. The pollution monitoring device 30 mainly includes the DUT 1 and the scintillator cloth-like member 2, a dark room 3 for accommodating the DUT 1 and the scintillator cloth-like member 2, and a plurality of light guides arranged on the inner wall of the dark room 3. 92 and a plurality of photodetectors 7 and an arithmetic circuit 8 for arithmetically processing the outputs of the photodetectors 7. Reference numeral 6 denotes light emitted from the scintillator cloth-like member 2.

The scintillator cloth-like member 2 has flexibility such that scintillation fibers or the like are woven into cloth, glass scintillator or the like is woven into cloth like ordinary glass fiber, or plastic scintillator or the like is finely cut. It is formed into a cloth by joining with an adhesive or the like.

Therefore, the scintillator cloth-like member 2 covers the object to be measured 1 or wraps the object to be measured 1 to measure the distance from the radioactive substance 4 of the object to be measured 1 to the range of α rays of about 5c.
It is easy to get close or close within m. The photodetector 7 is, in this embodiment, 10 photomultiplier tubes arranged on the inner wall of the dark room 3.

With such a configuration, the radiation 5 emitted from the radioactive substance 4 attached to the DUT 1 is detected by the scintillator cloth-like member 2 and converted into light. This light is guided by the light guide 92 to the photodetector 7 arranged on the inner wall of the dark room 3 and detected by the photodetector 7, and the output from the photodetector 7 is arithmetically processed by the arithmetic circuit 8. .

That is, the radiation 5 is converted into light very close to the radioactive substance 4, and the light is counted by the photodetector 7, so that the object 1 to be measured has unevenness, but has a short range α.
It becomes easier to detect lines and the like, and the measurement performance is improved.

(Effects of the Invention) As described above, according to the present invention, a scintillator cloth-like member which is formed in a cloth shape and is provided so as to wrap the object to be measured, the scintillator cloth-like member, and the object to be measured. A dark room for accommodating and a photodetector arranged on the inner wall of the dark room for detecting light emitted from the scintillator cloth-like member when radiation from radioactive contaminants of the object to be measured enters the scintillator cloth-like member. And the arithmetic circuit for arithmetically processing the output of the photodetector, it is possible to effectively solve the problem of the prior art that it is difficult to detect α-rays from an object to be measured with severe irregularities. . Also,
There is an effect that the measurement performance can be improved without complicating the structure of the pollution monitor.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of a conventional pollution monitoring device. 1: Object to be measured, 2: Scintillator cloth member, 3: Dark room, 4: Radioactive substance, 7: Photodetector, 30: Contamination monitor device.

Claims (1)

[Claims] 1. A contamination monitor for measuring the concentration of radioactive contaminants on the surface of an object to be measured, the scintillator being formed in a cloth shape and provided so as to cover or wrap the object to be measured. A cloth-like member, a dark room for accommodating the scintillator cloth-like member and the object to be measured, and radiation from a radioactive contaminant of the object to be measured which is disposed on the inner wall of the dark chamber and is incident on the scintillator cloth-like member. A contamination monitoring device comprising: a photodetector for detecting light emitted from the scintillator cloth-like member; and an arithmetic circuit for arithmetically processing an output from the photodetector.