JPH01195395A - Mobile radiation measuring instrument - Google Patents

Abstract

PURPOSE:To safely and surely measure the radiation on a vertical or ceiling wall surface with the remote control by providing wall surface attractors, a driving mechanism which drives a device longitudinally and transversely, and an analyzer which analyzes measured data from a radiation measurer. CONSTITUTION:A mobile radiation measuring instrument is provided with wall surface attractors 4 which attracts the device to the wall surface, a driving mechanism 2 which drives a vehicle body 1 longitudinally and transversely, and an analyzer 5 which analyzes measured data from a radiation measurer 3. Both sides of a caterpillar tread consisting of an endless body 8 stretched around wheels 7a, 7b, 7c, and 7d are rotated and driven to advance the vehicle body, and the driving force to right or left wheels from a motor is cut off by a clutch to turn the vehicle body 1 right or left. Therefore, the vehicle body is controlled forward or backward without steering devices. Thus, the radiation on the vertical or intrapipe wall surface which is difficult to measure in a conventional method is safely and surely measured.

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention is useful for measuring the amount of radioactive contamination of reactor structural materials and separating them according to the degree of radioactive contamination when disposing of a nuclear reactor. The present invention relates to a radiation measuring device, and particularly to a self-propelled radiation measuring device that is self-propelled by remote control by an operator.

``Prior art'' In general, when disposing of a nuclear reactor, in order to efficiently separate the reactor structural materials according to the degree of radioactive contamination,
It is necessary to measure the amount of radioactivity in the reactor structures. However, since these structures are large and have various shapes, it is difficult to measure them. For example, a nuclear reactor structure has vertical walls and inner wall surfaces of the ceiling, so it is not possible to use the normal hanging method. Therefore, in the past, scaffolding was installed inside the reactor containment vessel to measure the amount of radioactivity.

``Problem to be solved by the invention'' By the way, with the conventional radioactivity equipment mentioned above, each time a scaffold was set up inside the reactor to measure the amount of radioactivity inside the reactor structure, the work was difficult. It was dangerous at the same time. In particular, since the reactor structure has a complex shape, scaffolding work required skill.

The object of the present invention has been made in view of the above-mentioned drawbacks, and is a self-propelled radiation therapy system that can easily measure the amount of radioactivity without building scaffolding inside a large and complex nuclear reactor structure. The purpose of this invention is to provide a measuring device.

"Means for Solving the Problems" The self-propelled radiation measuring device according to the present invention uses a radiation measuring device and a device in order to run on various wall surfaces with its own blade and measure radiation without requiring a scaffold. It has a wall suction device that adsorbs to the wall and a drive mechanism that drives the device back and forth and left and right.The radiation measuring device can be freely adsorbed to the wall and can be moved vertically by remote control from the analyzer that analyzes the measurement data from the radiation measuring device. It is configured to measure radiation on walls or ceiling walls.

"Function" As described above, since the self-propelled radiation measuring device according to the present invention is equipped with an electromagnet in a part of the vehicle body, it is possible to self-propel along an arbitrarily inclined magnetic wall surface and measure radiation.

"Example" An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a side view of a self-propelled radiation measuring device showing an embodiment of the present invention. In the figure, the self-propelled radiation measuring device includes a vehicle body 1, a drive mechanism 2 that drives the vehicle body 1 back and forth, left and right, a radiation measuring device 3 mounted on the vehicle body 1, and a wall adsorption device that attaches the device to the wall. The radiation measuring device 4 includes an analyzer 5 for analyzing measurement data from the radiation measuring device 3, and a cable 6 for exchanging measurement data between the radiation measuring device 3 and the analyzer 5.

Here, the drive mechanism 2 includes wheels 7a, 7b, and 7c provided symmetrically on both sides of the vehicle body l.

It is composed of a caterpillar consisting of an endless body 8 stretched over a shaft 7d, a motor 9 for rotationally driving part or all of the wheels mentioned above, and the like. Further, the caterpillar can rotate one or both sides of the vehicle body 1 by means of a clutch (not shown). Therefore, if both sides of the caterpillar are driven to rotate, the vehicle will move forward, and if the clutch cuts off the drive from the motor to either the left or right, the vehicle will move toward the direction where the drive is cut off.
rotates. Therefore, the forward or backward direction of the vehicle body can be controlled without using a steering device. Current is supplied to the motor 9 on the vehicle body 1 via the cable 6. Further, when the vehicle body 1 is to be moved backward, the motor 9 may be reversed, or the wheels may be reversed via gears. Further, in order to reduce the weight of the vehicle, power is supplied to the motor 9 from the outside via the cable 6.

The radiation measuring device 3 uses sodium iodide (Nal), for example.
A radiation detector can be suitably used. G here
Since the e(Li) detector requires cooling with liquid nitrogen, it is not suitable for mounting on a self-propelled vehicle body. In contrast,
Although the resolution of sodium iodide (NaI) radiation detectors is slightly inferior, they do not require cooling and are lightweight and portable, making them suitable for mounting on self-propelled vehicles.

FIG. 2 is an enlarged schematic diagram showing the Nal radiation detector 3 and preamplifier 10. In the figure, a NAL radiation detector 3, a photomultiplier 10, and a preamplifier 11 are mounted on the vehicle body 1, and the measurement results from the NAL radiation detector 3 are sent to an analyzer 12 (not shown) via a data transfer cable 6. It is sent, analyzed and recorded.

Here, the T-rays from the reactor vessel are detected by the Nal radiation detector 3.
and generates photons. The generated photons are converted into photoelectrons by the photomultiplier tube 10 and converted into pulse signals. The pulse signal is amplified by a preamplifier 11 and then sent to an analyzer 12 via a cable 6, where the dose rate is measured.

Next, the specific operation of the self-propelled radiation measuring device configured as above will be explained. First, a self-propelled radiation measuring device is attached to the inner wall surface of the iron reactor containment vessel (PCV, RPV) 13, and while radiation (mainly T-rays) is measured by the NAL radiation detector 3, the caterpillar is driven to move forward. let

At this time, the self-propelled radiation measuring device does not fall because it is attracted to the inner wall surface of the reactor containment vessel (PCV, RPV) 13 by the magnetic force of the wall adsorber 4. Furthermore, when the self-propelled radiation measuring device is to turn right, it is sufficient to stop the right side of the caterpillar and drive only the left side. Further, when the vehicle body 1 is to be moved backward, the motor 9 may be reversed, or the wheels may be reversed via gears. Here, the strength of the magnetic force of the wall suction unit 4 may be sufficient as long as it can support the weight of the self-propelled radiation measuring device.

As described above, since the self-propelled radiation measuring device of the present invention moves the vehicle body l using caterpillars, it can move smoothly even if there are some irregularities in the reactor containment vessel 13.

In addition, since it is adsorbed to the wall surface by the wall suction device 4, it is possible to measure not only a vertical wall surface but also a ceiling portion without falling.

FIG. 3 is an explanatory diagram showing how the self-propelled radiation measuring device of the present invention is used. In the figure, an analyzer 12 is installed in a reactor containment vessel made of iron, and an operator operates a self-propelled radiation measuring device from below. Since the reactor containment vessel has a lower opening, piping opening, or upper opening, the self-propelled radiation measuring device must be operated while avoiding these openings.

Furthermore, since the reactor containment vessel is very large, when measuring at high places, the length of the cable becomes long and the weight increases, so the suction force of the wall suction device 4 must also be increased.

In the embodiment, a case has been described in which the data measured by the self-propelled radiation measuring device is amplified and then transferred to the analyzer via a cable, but the data is not limited to this and may be transferred to the analyzer wirelessly. When transmitting data to the analyzer wirelessly in this way, there is no need to take the weight of the cable into consideration, so there is no risk of the vehicle body falling even if the magnetic force of the wall adsorber 4 remains constant.

"Effects of the Invention" As explained in detail above, according to the self-propelled radiation measuring device of the present invention, the measuring person can operate from below by remote control without setting up dangerous scaffolding inside the reactor structure. Radiation can be measured. Therefore, it is difficult to measure vertical walls and mirror panels (ceiling inner wall surfaces) using conventional techniques.
Alternatively, it is possible to reliably and safely perform radiation measurements on pipe inner wall surfaces, etc. that are too large for humans to enter.

Furthermore, it becomes possible to measure radiation in areas with high radiation dose rates that cannot be directly measured by a human holding a measuring device in hand.

[Brief explanation of the drawing]

FIG. 1 is a side view of a self-propelled radiation measuring device showing an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the schematic configuration of the radiation measuring device of the present invention, and FIG. 3 is a self-propelled type of radiation measuring device of the present invention. FIG. 2 is an explanatory diagram showing how the radiation measuring device is used. 1... Vehicle body, 2... Drive mechanism, 3... Radiation measuring device, 4... Wall suction device, 5... Analyzer , 6... Cable, 7 a, 7 b, 7 c, 7 d-... Wheel, 8... Endless body, 9... Motor, 10. ...Photomultiplier tube, 11 ...Preamplifier, 12 ...Analyzer, 13 ...Reactor containment vessel. Applicant Japan Atomic Energy Corporation Agent
Patent attorney Umeo Yamauchi Fig. 1 Detection section of the miller Fig. 3 Dan

Claims (1)

[Claims] The radiation measuring device comprises: a radiation measuring device; a wall suction device for adhering the device to a wall surface; a drive mechanism for driving the device back and forth and left and right; and an analyzer for analyzing measurement data from the radiation measuring device. A self-propelled radiation measurement device that measures radiation on vertical walls or ceiling walls of reactor containment vessels, etc., by remote control from an analyzer.