KR102057189B1 - A method of detecting radioactive materials using unmanned aircraft - Google Patents

Abstract

A method of detecting a radioactive material using an unmanned aerial vehicle, the method comprising: (a) rotating a radiometer at a constant rotational speed while being mounted on an unmanned aerial vehicle; (b) average radiation in each particular direction with each radiation dose measured from the particular direction from each particular direction, with all directions directed to the radiometer as it is divided evenly into a plurality of specific directions Counting rate is calculated; (C) The radioactive material detection method comprising the step of calculating the moving distance of the unmanned aerial vehicle by inputting the average radiation coefficient of each specific direction calculated in step (b) as a variable of a predetermined formula.

Description

A method of detecting radioactive materials using unmanned aircraft

The present invention relates to a method for detecting a radioactive material using an unmanned aerial vehicle. Specifically, while the unmanned aerial vehicle is flying in the air, the radiation dose is measured while rotating at a constant rotational speed while the radiometer is mounted on the unmanned aerial vehicle, and measured If the radiation dose exceeds a constant reference radiation coefficient, the unmanned aerial vehicle performs the calculations set automatically to move in the specific direction in which the radiation dose is measured, and when the unmanned aerial vehicle moves in a specific direction and arrives where radioactive material is located It relates to a radioactive material detection method that can detect the location of the radioactive material by transmitting the current position information of the aircraft.

An unmanned aerial vehicle, such as a drone, is an aircraft that is not piloted, and can fly autonomously in automatic or semi-automatic format according to a pre-programmed route, or are equipped with artificial intelligence to perform its mission at its own discretion. Commonly referred to as aircraft. Unmanned aerial vehicles are equipped with various equipments depending on the field of application, and are being applied to various fields such as surveillance, reconnaissance, guidance of precision attack weapons, geological survey, construction, agriculture, mining, security, or public field.

Since the Fukushima nuclear power plant accident, the importance of radioactive detection methods has emerged in preparation for events such as explosions of nuclear power plants, terrorism using radioactive materials, and leakage and loss of radioactive materials.

Radioactive materials are not directly detectable by human senses. Therefore, in the past, people have directly explored radioactive materials using special equipment such as radiation detectors. This not only consumes a lot of time and money, but also carries the risk of human exposure to radioactive material. Recently, a technology for detecting radioactive material using a drone or a mobile robot equipped with a radiometer has been developed.

Conventional unmanned radioactive material detection technology includes the first method of detecting by mounting a radiometer on the drone, and the second method of detecting the position of the radioactive material at a specific position.

In the first technique, a drone equipped with a radiometer is effective for detecting radioactive material in a wide range of areas, but there is a limit to searching for the detailed location of radioactive material with a single radiometer. ) Manpower resources are consumed because of the detailed location search.

As a second technique, there is a method in which a Compton camera or the like is used as a method of detecting the position and direction of a radioactive material at a position where radiation is measured. Such a detection method is advantageous for the detailed search of the radioactive material at a fixed location, but requires expensive equipment and has limitations in locating radioactive materials in a wide area. Again, human resources are consumed because people have to search for detailed location.

Therefore, there is a need for a method of detecting radioactive material by using a relatively low-cost radiometer to move the drone to the point where the radioactive material is located by automatic control.

(Patent Document 1) KR10-1733542 B

In order to solve the problems according to the prior art described above, in the event of a nuclear power plant accident, terrorism using radioactive materials, leakage or loss of radioactive materials, an unmanned aerial vehicle such as a drone automatically measures radiation while radioactive materials are positioned. It is intended to provide a way to detect where radioactive materials are located by allowing them to be controlled and moved automatically.

Radioactive material detection method according to the present invention for solving the above problems, (a) the radiometer 200 is rotated at a constant rotation speed in a state mounted on the unmanned aerial vehicle (100); (b) In the state in which all the directions to which the radiation meter 200 faces according to rotation are divided evenly into a plurality of specific directions, each of the respective radiation doses measured by the radiation meter 200 from each specific direction Calculating an average radiation coefficient in a specific direction of the; (c) calculating the moving distance of the unmanned aerial vehicle 100 by inputting the average radiation coefficient in each specific direction calculated in step (b) as a variable of a predetermined equation.

Preferably, after the step (a), (a-1) the step of calculating the average radiation coefficient in all directions by the radiation dose measured by the radiation meter 200 during one rotation of the radiation meter 200 is further If the average radiation coefficient in all directions in the step (a-1) exceeds a predetermined reference radiation coefficient, step (b) proceeds.

Preferably, the average radiation coefficient in all directions in step (a-1) is calculated by Equation 1 below.

[Equation 1]

는 모든 방향의 평균방사선계수율, T는 방사선 계측기(200)의 1회전에 걸리는 시간, Q(t)는 방사선 계측기(200)의 1회전 동안 모든 방향에서 측정된 방사선량이다.In Equation 1

Is the average radiation coefficient in all directions, T is the time taken for one revolution of the radiometer 200, Q (t) is the radiation dose measured in all directions during one revolution of the radiometer 200.

Preferably, in the step (b), the average radiation coefficient in the specific direction is calculated by Equation 2 below.

[Formula 2]

는 i방향의 평균방사선계수율, i는 모든 방향 중 소정의 특정 방향, t_i는 i방향에서 방사선 계측기(200)가 방사선량을 측정한 시간, Q(t)는 i방향에서 t시간 동안 측정된 방사선량이다.In Equation 2,

Is the average radiation coefficient in the i direction, i is the predetermined specific direction among all directions, t _i is the time when the radiation meter 200 measures the radiation dose in the i direction, and Q (t) is measured during the t time in the i direction. Radiation dose.

Preferably, all of the directions are evenly divided in four of the particular directions.

Preferably, in step (c), the moving distance of the unmanned aerial vehicle 100 is calculated by Equation 3 and Equation 4 below.

[Equation 3]

는 4개의 특정 방향 중 무인항공기(100)를 중심으로 대칭되는 2개의 특정 방향 중 어느 한 특정 방향의 평균방사선계수율,

는

에 해당되는 특정 방향에 무인항공기(100)를 중심으로 대칭되는 다른 한 특정 방향의 평균방사선계수율이다.In Equation 3, d _x is the moving distance in the horizontal direction of the unmanned aerial vehicle 100, a _n is the moving distance constant in the nth movement of the unmanned aerial vehicle 100,

Is the average radiation coefficient of any one of two specific directions symmetric about the unmanned aerial vehicle 100 of the four specific directions,

Is

The average radiation coefficient of one specific direction is symmetrical about the unmanned aerial vehicle 100 in a specific direction corresponding to.

[Equation 4]

는

및

에 해당되는 2개의 특정 방향을 제외한 나머지 2개의 특정 방향 중 어느 한 특정 방향의 평균방사선계수율,

는

에 해당하는 특정 방향에 무인항공기(100)를 중심으로 대칭되는 다른 특정 방향의 평균방사선계수율이다.In Equation 4, d _y is the moving distance in the front and rear direction of the unmanned aerial vehicle 100, a _n is the moving distance constant in the nth movement of the unmanned aerial vehicle 100,

Is

And

Average radiation coefficient in any one of the two specific directions, except for two specific directions,

Is

Average radiation coefficient of the other specific direction is symmetric about the unmanned aerial vehicle 100 in a specific direction corresponding to.

Preferably, (d) when both of the following Equation 5 and Equation 6 are satisfied, the unmanned aerial vehicle 100 is stopped in the GPS device 300 mounted on the unmanned aerial vehicle 100 while the unmanned aerial vehicle 100 is stopped. Further comprising the step of transmitting the GPS location information.

[Equation 5]

[Equation 6]

,

,

및

는 상기 수식 3 및 수식 4의 설명에 따른다.In Equations 5 and 6, C is a predetermined reference value,

,

,

And

Follows the description of Equations 3 and 4.

As a problem solving means described above, an unmanned aerial vehicle equipped with a low-cost radiometer may be used to automatically move to a place where radioactive material is located, thereby drastically reducing the cost and time for precise radioactive material detection.

In addition, the use of the present invention in various radiological disaster centers, radioactive material handling facilities, etc., where it is difficult to introduce a radioactive material detection technology using an unmanned aerial vehicle, can easily and effectively cope with various radioactive material related accidents at low cost.

1 is a flow chart for a radioactive material detection method according to the present invention.
2 is a perspective view showing a state in which the radiometer is rotated in the state mounted on the unmanned aerial vehicle.
3 is a diagram illustrating a state in which all directions are equally divided into four specific directions while the radiometer mounted on the unmanned aerial vehicle is rotated.
4 and 5 are diagrams showing experimental results.

Hereinafter, preferred embodiments of the method according to the present invention will be described with reference to the accompanying drawings. In this process, the thickness of the lines or the size of the components shown in the drawings may be exaggerated for clarity and convenience of description. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or convention of a user or an operator. Therefore, the definitions of these terms should be made based on the contents throughout the specification.

A description with reference to FIGS. 1 to 3.

The detection apparatus used in the radioactive material detecting method according to the present invention includes an unmanned aerial vehicle 100, a radiation measuring instrument 200 mounted on the unmanned aerial vehicle 100, and a GPS device 300 mounted on the unmanned aerial vehicle 100. .

The unmanned aerial vehicle 100 may be an aircraft that is flying unmanned, preferably a drone. The unmanned aerial vehicle 100 may be provided with a motor 120 that provides a constant rotational force, the radiation measuring instrument 200 is connected to the motor 120 can be rotated at a constant rotational speed. The GPS device 300 transmits the location information of the unmanned aerial vehicle 100 when predetermined conditions to be described below are met.

The radiation shield 220 is positioned on the outer surface of the radiation meter 200 to minimize the influence on the radiation meter 200 due to radiation generated outside a specific angle.

S100: all directions of the rotating radiation meter 200 is directed Average radiation coefficient  Calculation

The radiation meter 200 is rotated at a constant rotational speed in a state where it is mounted on the unmanned aerial vehicle 100. While the radiometer 200 is rotated, the radiation dose from all directions to which the radiometer 200 is directed is measured.

The average radiation coefficient in all directions toward which the rotating radiometer 200 is directed is calculated by Equation 1 below.

[Equation 1]

는 모든 방향의 평균방사선계수율, T는 방사선 계측기(200)의 1회전에 걸리는 시간, Q(t)는 모든 방향에서 방사선 계측기(200)의 1회전 동안 측정된 방사선량이다.In Equation 1

Is the average radiation coefficient in all directions, T is the time taken for one revolution of the radiometer 200, Q (t) is the radiation dose measured during one revolution of the radiometer 200 in all directions.

S200: all directions of Mean radiation coefficient  Prescribed Reference Radiation Coefficient  compare

The predetermined reference radiation coefficient is preset as an acceptable radiation coefficient. If the average radiation coefficient in all directions is below the predetermined reference radiation coefficient, the radiation dose from all directions is continuously measured to calculate the average radiation coefficient in all directions.

S300: in a number of specific directions Average radiation coefficient  Calculation

When the average radiation coefficient in all directions exceeds a predetermined reference radiation coefficient, all directions are divided evenly into a plurality of specific directions. When looking at the unmanned aerial vehicle 100 positioned below the top of the unmanned aerial vehicle 100, the radiation measuring apparatus 200 mounted on the unmanned aerial vehicle 100 is divided into a plurality of specific directions evenly in a circular state that is drawn while rotating. do.

3 illustrates a state in which all directions are divided into four specific directions.

The average radiation coefficient in the specific direction is calculated by Equation 2 below.

[Formula 2]

는 i방향의 평균방사선계수율, t_i는 i방향에서 방사선 계측기(200)가 방사선량을 측정한 시간, Q(t)는 i방향에서 t시간 동안 측정된 방사선량이다.In Equation 2, i is a predetermined specific direction divided evenly among all directions,

Is the average radiation coefficient in the i direction, t _i is the time the radiation meter 200 measured the radiation dose in the i direction, Q (t) is the radiation dose measured for t hours in the i direction.

S400: many specific directions Average radiation coefficient  Prescribed conditions Are you satisfied part

The average radiation coefficient of a particular direction is calculated in a number of specific directions evenly divided from all directions.

In an embodiment of the present invention, which is divided equally into four specific directions from all directions, the average radiation coefficient in four specific directions is inputted as a variable of a predetermined equation, the predetermined reference value and the comparative evaluation are as follows. Equation 5 and 6 are made.

[Equation 5]

[Equation 6]

,

,

및

는 후술할 수식 3 및 수식 4의 설명에 따른다.In Equations 5 and 6, C is preset to a predetermined reference value,

,

,

And

Follows the description of Equations 3 and 4 to be described later.

S500: calculation of moving distance of unmanned aerial vehicle 100

When the average radiation coefficient in a plurality of specific directions in the step S400 is higher than the predetermined reference value set in advance, that is, the formula 5 and 6 does not satisfy the absolute value of the values entered in Equations 5 and 6, unmanned The aircraft 100 is moved. There is still a concentration of radiation from a particular direction, which is not close to the location of the radioactive material.

In one embodiment of the present invention in which all directions are equally divided into four specific directions, the moving distance calculation of the unmanned aerial vehicle 100 is based on Equations 3 and 4 below.

[Equation 3]

는 4개의 특정 방향 중 무인항공기(100)를 중심으로 대칭되는 2개의 특정 방향 중 어느 한 특정 방향의 평균방사선계수율,

는

에 해당되는 특정 방향에 무인항공기(100)를 중심으로 대칭되는 다른 한 특정 방향의 평균방사선계수율이다.In Equation 3, d _x is the moving distance in the horizontal direction of the unmanned aerial vehicle 100, a _n is the moving distance constant in the nth movement of the unmanned aerial vehicle 100,

Is the average radiation coefficient of any one of two specific directions symmetric about the unmanned aerial vehicle 100 of the four specific directions,

Is

The average radiation coefficient of one specific direction is symmetrical about the unmanned aerial vehicle 100 in a specific direction corresponding to.

[Equation 4]

는

및

에 해당되는 2개의 특정 방향을 제외한 나머지 2개의 특정 방향 중 어느 한 특정 방향의 평균방사선계수율,

는

에 해당하는 특정 방향에 무인항공기(100)를 중심으로 대칭되는 다른 특정 방향의 평균방사선계수율이다.In Equation 4, d _y is the moving distance in the front and rear direction of the unmanned aerial vehicle 100, a _n is the moving distance constant in the nth movement of the unmanned aerial vehicle 100,

Is

And

Average radiation coefficient in any one of the two specific directions, except for two specific directions,

Is

Average radiation coefficient of the other specific direction is symmetric about the unmanned aerial vehicle 100 in a specific direction corresponding to.

The moving distance of the unmanned aerial vehicle 100 may be adjusted through the moving distance constant a _n . For example, the first movement may be set to 50 cm, the second movement to 40 cm, the third movement to 30 cm, the fourth movement to 20 cm, and the movement after the fourth time exceeds 10 cm.

After moving by the calculated movement distance, step S300 is performed again.

S600: unmanned aerial vehicle (100) Stop moving  And unmanned aerial vehicle 100 location information transmission

If the average radiation coefficients in a plurality of specific directions in step S400 is input to Equation 5 and Equation 6, the absolute value of my value is lower than the predetermined predetermined reference value, that is, the equation 5 and Equation 6, the unmanned aerial vehicle The 100 is stopped and the GPS position information of the unmanned aerial vehicle 100 is transmitted to the predetermined place through the GPS device 300 in the stopped state. Similar radiation doses from all directions are measured when the unmanned aerial vehicle 100 is close to the location of the radioactive material.

Experimental Example

It demonstrates with reference to FIG. 4 and FIG.

The effectiveness of the radioactive material detection method according to the present invention was evaluated by two experiments using the MCNP6 code, one of Monte Carlo radiation transport analysis codes.

Experimental Example Case A is a case where the radioactive material of Co-60 having a total radioactivity of 877 μCi is located at -5 cm <x <5 cm & 190 cm <y <200 cm.

Experimental Example Case B is a case where a Co-60 radioactive material having a total radioactivity of 1.77 mCi is located at 150 cm <x <160 cm & 150 cm <y <160 cm.

The radioactive material detection method according to the present invention was applied using a drone located 50 cm above the ground.

-

)을 평가하였으며, 본 발명에 따른 방사성물질 탐지방법에 따른 시뮬레이션을 수행하였다. 방사선 계측 효율은 10%로 가정하였으며, 소정의 기준방사선계수율은 620#/s로 가정하였다. The average radiation coefficient in four specific directions from the rotatable radiation meter 200 with θ = 45 ^o (

-

), And the simulation according to the radioactive material detection method according to the present invention was performed. The radiation measurement efficiency was assumed to be 10%, and the predetermined reference radiation coefficient was assumed to be 620 # / s.

In addition, a _n is set to 50 cm (n = 1), 40 cm (n = 2), 30 cm (n = 3), 20 cm (n = 4), 10 cm (n> 4), and the predetermined reference value C is Set to 0.05 (5%). According to the set criteria, the above-described step S300 was performed at the position (x = 0 cm, y = 0 cm).

As shown in Figure 4 and 5, through the radioactive material detection method according to the invention it was shown that the drone moves precisely to the place where the radioactive material, the radioactive material detection method according to the present invention It can be seen that it can be efficiently applied to precise search.

In the present specification, the present invention has been described with reference to the embodiments shown in the drawings so that those skilled in the art can easily understand and reproduce the present invention, which is merely exemplary, and those skilled in the art can make various modifications and equivalents from the embodiments of the present invention. It will be appreciated that embodiments are possible. Therefore, the protection scope of the present invention will be defined by the claims.

100: unmanned aerial vehicle
120: motor
200: radiation meter
220: radiation shield
300: GPS device

Claims (7)

(a) rotating the radiation meter 200 at a constant rotational speed while being mounted on the unmanned aerial vehicle 100;
(b) In the state in which all the directions to which the radiation meter 200 faces according to rotation are divided evenly into a plurality of specific directions, each of the respective radiation doses measured by the radiation meter 200 from each of the specific directions Calculating an average radiation coefficient in a specific direction of the;
(c) calculating the moving distance of the unmanned aerial vehicle 100 by inputting the average radiation coefficient in each specific direction calculated in step (b) as a variable of a predetermined formula;
All the directions are divided equally into four specific directions,
In the step (c), the moving distance of the unmanned aerial vehicle 100 is calculated by the following equation 3 and the following radioactive material detection method:

[Equation 3]

In Equation 3, d _x is the moving distance in the horizontal direction of the unmanned aerial vehicle 100, a _n is the moving distance constant in the nth movement of the unmanned aerial vehicle 100,

Is the average radiation coefficient of any one of two specific directions symmetric about the unmanned aerial vehicle 100 of the four specific directions,

Is

Average radiation coefficient in one specific direction is symmetrical about the unmanned aerial vehicle 100 in a specific direction corresponding to the.

[Equation 4]

In Equation 4, d _y is the moving distance in the front and rear direction of the unmanned aerial vehicle 100, a _n is the moving distance constant in the nth movement of the unmanned aerial vehicle 100,

Is

And

Average radiation coefficient in any one of the two specific directions, except for two specific directions,

Is

Average radiation coefficient of the other specific direction is symmetric about the unmanned aerial vehicle 100 in a specific direction corresponding to.
The method of claim 1,
After the step (a),
(A-1) further comprising the step of calculating the average radiation coefficient in all directions by the radiation dose measured on the radiation meter 200 during one rotation of the radiation meter 200,
And (b) if the average radiation coefficient in all directions in step (a-1) exceeds a predetermined reference radiation coefficient.
The method of claim 2,
Mean radiation coefficient in all directions in the step (a-1) is calculated by the following formula 1 Radioactive material detection method:

[Equation 1]

In Equation 1

Is the average radiation coefficient in all directions, T is the time taken for one revolution of the radiometer 200, Q (t) is the radiation dose measured in all directions during one revolution of the radiometer 200.
The method of claim 3, wherein
In the step (b), the average radiation coefficient of the specific direction is calculated by the following formula 2 radioactive material detection method:

[Formula 2]

In Equation 2,

Is the average radiation coefficient in the i direction, i is the predetermined specific direction among all directions, t _i is the time when the radiation meter 200 measures the radiation dose in the i direction, and Q (t) is measured during the t time in the i direction. Radiation dose.
delete delete The method of claim 1,
(d) When both of the following Equation 5 and Equation 6 conditions are satisfied, the GPS location information of the unmanned aerial vehicle 100 in the GPS device 300 mounted on the unmanned aerial vehicle 100 while the unmanned aerial vehicle 100 is stopped. Radioactive material detection method further comprises the step of transmitting:

[Equation 5]

[Equation 6]

In Equations 5 and 6, C is a predetermined reference value,

,

,

And

Follows the description of Equations 3 and 4.

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