JP2000039476A - Goods survey meter - Google Patents

Abstract

(57) [Summary] To provide an article survey meter that reduces the time and labor burden of an operator when measuring contamination of a large article by a radioactive substance. A radiation detector moving means for supporting and easily moving the radiation detector mounted on a movable carriage, and a radiation detector incorporating a large-area plastic scintillator are provided. ing. The radiation detector moving means includes a moving means main body 41 on a gantry 45 of the carriage and 1
A pair of up / down movement arms 42, a horizontal movement arm 43, a holding arm 44, and a holding member 3 having a handle 2 or the like as input means are provided. The radiation detector 1 is horizontally moved by the rotation of the moving means main body 41 and the horizontal movement arm 43, and is vertically moved by the rotation of the vertical movement arm 42. The radiation detector 1 can be easily moved with a small input to the handle 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an article survey meter for measuring contamination of a surface of a large article used by a radioactive substance handling facility or the like by the radioactive substance.

[0002]

2. Description of the Related Art An article survey meter is used to determine whether the surface of an article used in a facility handling radioactive materials or the like is contaminated by a radioactive substance.
The sensitive area of the radiation detector used in the prior art article survey meter is as small as about φ50 mm, and the operator measures the article survey meter by hand when using it. Therefore, the work efficiency is low, and in particular, when measuring surface contamination of a large article such as a cylinder or a switchboard, there is a problem that a burden is increased in both time and labor of an operator.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide an article survey meter which has good working efficiency, can reduce working time, and reduces the burden on the operator. That is.

[0004]

According to the present invention, there is provided an article survey meter for measuring the contamination of the surface of a large article used by a radioactive substance handling facility or the like by a radioactive substance, comprising a radiation detector having a large sensitive area. Input means for inputting a direction in which the radiation detector is moved, and detector moving means for supporting the weight of the radiation detector and moving the radiation detector in accordance with an input from the input means. Item 1)).

The work area can be shortened due to the large sensitive area, and the detector moving means is employed, so that the heavy radiation detector can be easily moved by operating the input means with a small force. According to the first aspect of the present invention, there is provided a sensitive surface inclination angle adjusting means for adjusting the inclination of the sensitive surface of the radiation detector and a means for locking the inclination angle (the invention of the second aspect).

[0006] The locking means makes it easier to measure a plane having an arbitrary inclination. Further, in the invention of claim 1, the moving speed of the radiation detector is indicated by the background value (the invention of claim 3). By instructing the moving speed, corresponding to the background value,
It becomes possible to measure the actual measurement count value that can secure the required accuracy.

Further, in the first aspect of the present invention, the radiation shield of the radiation detector is adjusted by the background value (the fourth aspect of the present invention). By adjusting the radiation shield in accordance with the background value, it is possible to set the actually measured count value at which the required accuracy can be secured to a low level, so that the measurement time can be reduced.

Further, in the invention of claim 1, the position of the sensitive part of the radiation detector is displayed on the surface of the radiation detector (the invention of claim 5). The position indication of the sensitive part of the radiation detector facilitates the alignment, and the surface of the article to be measured can be measured accurately and quickly.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an article survey meter according to the present invention will be described with reference to an embodiment. FIG.
1 is a perspective view showing a configuration of an embodiment of an article survey meter according to the present invention.

Although not shown in FIG. 1, the entire article survey meter includes a movable cart on casters. FIG. 1 shows a portion mounted on a gantry 45 on a trolley. The radiation detector 1 incorporates a plastic scintillator having a sensitive area larger than that of the prior art, for example, 300 mm × 100 mm, and has a thickness of 10 mm.
Including the radiation shield of mm lead, the total weight is 50kg. In order to support and easily move such a radiation detector 1, a radiation detector moving means is provided.

The radiation detector moving means is a main body of the radiation detector moving means on the gantry 45 (in FIG. 1, a moving means main body).
41, a pair of vertical movement arms 42, and a horizontal movement arm
43, a holding arm 44, and a holding member 3 having a handle 2 as input means. The moving means main body 41 mounted on the gantry 45 can rotate left and right, and moves the radiation detector 1 largely left and right. The pair of up / down moving arms 42 project from one side surface of the moving means main body 41 and can rotate up and down to move the radiation detector 1 up and down. A horizontal movement arm 43 is attached to the upper end of the arm 42, and moves the radiation detector 1 left and right by rotating left and right. By the combined operation of the rotation of the arm 43 and the rotation of the moving means main body 41, the radiation detector 1 is horizontally moved. Therefore, the range of horizontal movement of the radiation detector is determined by the combined operation of the rotation of the horizontal movement arm 43 and the rotation of the moving means main body 41. A detector holding arm (holding arm in FIG. 1) 44 is attached to the tip of the horizontal movement arm 43 in a hanging shape, and the radiation detector 1 is attached to the lower end of the detector holding arm 44 via the holding member 3. Have been. The holding member 3 has a handle 2 as input means for inputting a direction in which the radiation detector 1 is to be moved, and a "measurement" indicating that measurement is being performed.
A display lamp 31, a "contamination" display lamp 32 for displaying surface contamination when detected, and a buzzer 33 for notifying the contamination by voice are provided. Also, the detector holding arm 44
Has a built-in strain gauge (not shown) for detecting the force input to the handle 2.

The radiation detector moving means includes a moving means main body 41, a vertical moving arm 42, and a horizontal moving arm.
A mechanism for keeping the direction of the radiation detector 1 constant with respect to the rotation of 43 is incorporated.
Even if the radiation detector 1 is moved by rotating the arm 42 and the arms 42 and 43, the direction of the radiation detector 1 can always be kept constant.

Further, the surface of the radiation detector 1 is provided with a highly visible color band indicating the sensitive portion, and the radiation detector 1 is fixed with the cart of the article survey meter fixed.
Indicate the range in which the contamination state can be measured.
When measuring the contamination state of radioactive substances in an article using such an article survey meter, the worker moves the article survey meter to the side of the article to be measured, and after fixing the cart at an appropriate position, first, , A background value (hereinafter abbreviated as BG value) at that location. It is necessary to measure the BG value because the BG value in the environment where the article survey meter is used is not constant,
This is because the operator needs to adjust the counting time, in other words, the moving speed of the radiation detector 1 according to the BG value of the use environment. The measurement of the BG value is performed in a state where the sensitive surface of the radiation detector 1 faces downward to avoid the influence from the article to be measured. Based on the measured BG values, an arithmetic unit built in the moving means main body 41 calculates the moving speed of the radiation detector 1 and displays the calculated value on the display 41 of the moving means main body 41.
Indicate in 1 to inform the operator. Usually this speed is
It is about 30 mm / sec. As the BG value increases, the moving speed decreases, and as the BG value decreases, the moving speed increases.

Further, depending on the magnitude of the measured BG value, it is effective to add a radiation shield of the radiation detector 1 to reduce the influence of the BG value. When the influence of the BG value is reduced, the optimum movement speed of the radiation detector 1 can be increased, so that the workability is improved. Subsequently, the operator brings the sensitive part of the radiation detector 1 close to the object to be measured by a predetermined distance with the handle 2, and based on the instruction value of the moving speed of the radiation detector 1 displayed on the display unit 411. Then, a force is applied to the handle 2 in the direction in which the radiation detector 1 is to be moved. The radiation detector moving means described above moves the radiation detector 1 by this force, and measurement of surface contamination is performed. During the measurement,
The "measurement" display lamp 31 is turned on, and at the same time, "measurement" is also displayed on the display section 411 of the moving means main body 41. When a contamination state is detected as a result of the measurement, the "contamination" display lamp 32 is turned on, "contamination" is displayed on the display section 411 and its data are also displayed, and the buzzer 33 emits an alarm sound. .

If the entire surface to be measured by one movement cannot be measured, the carriage is moved by the width that can be measured by one measurement, and the same measurement is performed again. This operation is repeated as necessary to measure the entire surface. As described above, according to the present invention, the worker can freely move the radiation detector 1 close to the object to be measured and move the radiation detector 1 in a desired direction with a small force.

When the surface of the object to be measured is a curved surface or an inclined surface, the sensitive surface of the radiation detector 1 can be inclined by twisting the handle 2 so that the object to be measured and the radiation detector 1 can be tilted. Can be made substantially constant over the entire sensitive portion of the radiation detector 1. The adjustment range of the tilt of the sensitive surface can be adjusted up to 90 degrees left and right, assuming that the case where the sensitive surface is facing directly below is 0 degree. Therefore, it is possible to handle from a horizontal plane to both right and left vertical planes. Normally, it is not necessary to tilt more than this, but it is also possible to tilt further if necessary. Although not shown, a means for locking the inclination is also provided, and the locking of the locking means can prevent the inclination of the sensitive surface from being changed by the moving operation. In actual measurement,
Because most horizontal or vertical measurements are taken, 0 ° and 90 °
It is effective to lock only the degree.

As is clear from the above description, according to this embodiment, the state of surface contamination of a large article by radioactive substances can be accurately measured with excellent work efficiency while reducing the time and labor burden on the operator. can do.

[0018]

According to the present invention, there is provided an article survey meter for measuring the contamination of the surface of a large article used by a radioactive substance handling facility or the like with a radioactive substance, comprising a radiation detector having a large sensitive area, and a radiation detector. Input means for inputting the direction in which the detector is moved, and detector moving means for supporting the weight of the radiation detector and moving the radiation detector in accordance with the input from the input means, so that the work time is reduced. The heavy radiation detector can be easily moved simply by operating the input means. Therefore,
It is possible to provide an article survey meter which has a high work efficiency, can shorten the work time, and reduces the burden on the worker (the invention of claim 1).

According to the first aspect of the present invention, since the sensitive surface inclination angle adjusting means for adjusting the inclination of the sensitive surface of the radiation detector and the means for locking the inclination angle are provided, the radiation detector has an arbitrary inclination. The measurement of the plane becomes easier. Therefore,
It is possible to provide an article survey meter with higher working efficiency and less burden on the operator (the invention of claim 2).

Further, in the first aspect of the present invention, since the moving speed of the radiation detector is indicated by the background value, it is possible to measure an actually measured count value corresponding to the background value and capable of securing necessary accuracy. Therefore, the contamination state can always be measured accurately (the invention of claim 3). Further, in the invention of claim 1,
Since the radiation shield of the radiation detector is adjusted according to the background value, the measured count value for ensuring the required accuracy can be set to a low level, so that the measurement time can be reduced. Therefore, it is possible to always measure at the optimum work efficiency while securing the required accuracy (the invention of claim 4).

Furthermore, according to the first aspect of the present invention, since the position of the sensitive part of the radiation detector is displayed on the surface of the radiation detector, the positioning of the radiation detector is facilitated, and the surface of the article to be measured is easily detected. Can be measured accurately and quickly. Therefore, the measurement becomes more accurate and the working efficiency is further improved (the invention of claim 5).

[Brief description of the drawings]

FIG. 1 is a perspective view showing the structure of an embodiment of an article survey meter according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Radiation detector 2 Handle 3 Holding member 31 Display lamp during measurement 32 Contamination display lamp 33 Buzzer 41 Main body of moving means 411 Display section 42 Arm for vertical movement 43 Arm for horizontal movement 44 Detector holding arm 45 Stand

Claims (5)

[Claims] 1. An article survey meter for measuring contamination of a surface of a large article used by a radioactive substance handling facility or the like by a radioactive substance, comprising: a radiation detector having a large sensitive area; and a moving direction of the radiation detector. An article survey meter comprising: input means for inputting; and detector moving means for supporting the weight of the radiation detector and moving the radiation detector in accordance with an input from the input means. 2. The article according to claim 1, further comprising a sensitive surface inclination angle adjusting means for adjusting the inclination of the sensitive surface of the radiation detector, and means for locking the inclination angle. Survey meter. 3. The article survey meter according to claim 1, wherein the moving speed of the radiation detector is indicated by a background value. 4. The article survey meter according to claim 1, wherein the radiation shield of the radiation detector is adjusted by a background value. 5. The radiation detector according to claim 1, wherein the position of the sensitive part of the radiation detector is displayed on a surface of the radiation detector.
Item survey meter according to 1.